Guide for Building and Classing High Speed Craft

GUIDEFORBUILDING ANDCLASSING

HIGH-SPEED CRAFT

OCTOBER 2001

American Bureau of ShippingIncorporated by Act of the Legislature ofthe State of New York 1862

Copyright 2001American Bureau of ShippingABS Plaza16855 Northchase DriveHouston, TX 77060 USA

Foreword

This Guide has been prepared to update the requirements of the ABS “Guide for Building and ClassingHigh-Speed Craft October 1990”. An attempt has been made to update the Guide to incorporate currentdesign practice and various types of hull design, e.g. catamarans, hydrofoils. The new Section 5/1 “CraftIntended to Carry Passengers” has also been developed in response to the needs from high-speed passengercraft industry and operators.

The Guide specifies machinery requirements and hull construction requirements based on three differentmaterials, namely, steel, aluminum alloys and fiber reinforced plastics (FRP) which are considered to bebroadly applied in the design of high-speed craft. The construction requirements are contained in a singlebooklet while the material requirements are published in two separate booklets, “Rule Requirements forMaterials and Welding Part 2” for steel and “Requirements for Materials and Welding Part 2 - Aluminumand Fiber Reinforced Plastics (FRP)”. These two booklets specify the requirements for these materials asapplicable, welding (metals) and connections (FRP).

This Guide becomes effective immediately after publication in February 1997 and supersedes the 1990version mentioned above.

Foreword to the 2001 Edition

This edition of the Guide has been published in October 2001, and the following changes have been madefrom the original version:

− Part 1, Section 3, titled “Surveys After Construction” has been removed as a consequence of theconsolidated version of the ABS Rule Requirements for Survey After Construction – Part 7, 2001being issued effective 1 January 2001. *

− The latest editions of the ABS Rule Requirements for Materials and Welding – Part 2 are applicable.

− Corrigenda/editorial items have been incorporated into the current edition.

* The PDF file of this booklet is available for download on the ABS website at:www.eagle.org/rules/downloads.html.

GUIDE FOR BUILDING AND CLASSING

HIGH-SPEED CRAFT

Contents

PART

1 Classification and Testing

2 Rule Requirements for Materials and Welding - Chapters1, 2, 3 and 4 (published as a separate booklet, 2001*)

Requirements for Materials and Welding, - Aluminum,- Fiber Reinforced Plastics (FRP) - Sections 4 and 5 (published as a separate booklet, 1997)

3 Hull Construction and Equipment

4 Machinery Equipment and Systems

5 Specialized Craft and Services

* The PDF file of this booklet is available for downloading on the ABS Website atwww.eagle.org/rules/downloads.html.

PART 1

Contents

Classification and Testing

SECTION

1 Scope and Conditions of Classification2 Testing and Trials During Construction - Hull

PART 1 SECTION 1|1 Scope and Conditions of Classification

PART 1 SECTION 1

Scope and Conditions of Classification

1/1.1 Classification

1/1.1.1 ProcessThe Classification process consists of a) thedevelopment of rules, guides, standards and othercriteria for the design and construction of marine craftand structures, for materials, equipment andmachinery, b) the review of design and survey duringand after construction to verify compliance with suchrules, guides, standards or other criteria, c) theassignment and registration of class when suchcompliance has been verified, and d) the issuance of arenewable Classification certificate, with annualendorsements, valid for five years.

The Rules, Guides, and standards are developedby Bureau staff and passed upon by committees madeup of naval architects, marine engineers, shipbuilders,engine builders, steel makers and by other technical,operating and scientific personnel associated with theworldwide maritime industry. Theoretical researchand development, established engineering disciplines,as well as satisfactory service experience are utilizedin their development and promulgation. The Bureauand its committees can act only upon such theoreticaland practical considerations in developing Rules,Guides and standards.

For classification, the craft are to comply withboth the hull and the machinery requirements of theRules and Guides.

1/1.1.2 Certificates and Reportsa Plan review and surveys during and after

construction are conducted by the Bureau to verify toitself and its committees that a craft, structure, item ofmaterial, equipment or machinery is in compliancewith the Rules, Guides, standards or other criteria ofthe Bureau and to the satisfaction of the attendingsurveyor. All reports and certificates are issuedsolely for the use of the Bureau, its committees, itsclients and other authorized entities.

b The Bureau will release information fromreports and certificates to the Port State to assist inrectification of deficiencies during port state controlintervention. Such information includes text ofconditions of classification, survey due dates, andcertificate expiration dates. The Owner will beadvised of any request and/or release of information.

c The Bureau will release certain information tothe craft’s hull underwriters and P&I clubs forunderwriting purposes. Such information includestext of overdue conditions of classification, surveydue dates, and certificate expiration dates. TheOwners will be advised of any request and/or releaseof information. In the case of overdue conditions ofclassification, the Owners will be given theopportunity to verify the accuracy of the informationprior to release.

1/1.1.3 Representations as to ClassificationClassification is a representation by the Bureau as tothe structural and mechanical fitness for a particularuse or service in accordance with its Rules, Guidesand standards. The Rules of the American Bureau ofShipping are not meant as a substitute for theindependent judgment of professional designers,naval architects and marine engineers nor as asubstitute for the quality control procedures ofshipbuilders, engine builders, steel makers, suppliers,manufacturers and sellers of marine vessels,materials, machinery or equipment. The Bureau,being a technical society, can only act throughSurveyors or others who are believed by it to beskilled and competent.

The Bureau represents solely to the vessel Owneror client of the Bureau that when assigning class itwill use due diligence in the development of Rules,Guides and standards, and in using normally appliedtesting standards, procedures and techniques as calledfor by the Rules, Guides, standards or other criteria ofthe Bureau for the purpose of assigning andmaintaining class. The Bureau further represents tothe vessel Owner or other client of the Bureau that itscertificates and reports evidence compliance onlywith one or more of the Rules, Guides, standards orother criteria of the Bureau in accordance with theterms of such certificate or report. Under nocircumstances whatsoever are these representations tobe deemed to relate to any third party.

1/1.1.4 Scope of ClassificationNothing contained in any certificate or report is to bedeemed to relieve any designer, builder, Owner,manufacturer, seller, supplier repairer, operator, otherentity or person of any warranty express or implied.Any certificate or report evidences compliance onlywith one or more of the Rules, Guides, standards orother criteria of American Bureau of Shipping and is


issued solely for the use of the Bureau, itscommittees, its clients or other authorized entities.Nothing contained in any certificate, report, plan ordocument review or approval is to be deemed to be inany way a representation or statement beyond thosecontained in 1/1.1.3. The validity, applicability andinterpretation of any certificate, report, plan ordocument review or approval are governed by theRules, Guides and standards of American Bureau ofShipping who shall remain the sole judge thereof. TheBureau is not responsible for the consequencesarising from the use by other parties of the Rules,Guides, standards or criteria of the American Bureauof Shipping, without review, plan approval andsurvey by the Bureau.

The term "approved" shall be interpreted to meanthat the plans, reports or documents have beenreviewed for compliance with one or more of theRules, Guides, standards, or other criteria of theBureau.

The Guide is published on the understanding thatresponsibility for stability and trim, for reasonablehandling and loading, as well as for avoidance ofdistributions of weight which are likely to set upabnormally severe stresses in vessels does not restupon the Committee. Speed is to be appropriatelyreduced with increasing sea conditions in order tolimit dynamic hull responses.

1/1.2 Suspension and Cancellation of Class

1/1.2.1 Termination of ClassificationThe continuance of the Classification of any craft isconditional upon the Guide requirements forperiodical, damage and other surveys being dulycarried out. The Committee reserves the right toreconsider, withhold, suspend, or cancel the class ofany craft or any part of the machinery fornoncompliance with the Guide, for defects reportedby the Surveyors which have not been rectified inaccordance with their recommendations, or fornonpayment of fees which are due on account ofClassification, Statutory and Cargo Gear Surveys.Suspension or cancellation of class may take effectimmediately or after a specified period of time.

1/1.2.2 Notice of SurveysIt is the responsibility of the Owner to ensure that allsurveys necessary for the maintenance of class arecarried out at the proper time. The Bureau will giveproper notice to an Owner of upcoming surveys. Thismay be done by means of a letter, a quarterly vesselstatus or other communication. The non-receipt ofsuch notice, however, does not absolve the Ownerfrom his responsibility to comply with surveyrequirements for maintenance of class.

1/1.2.3 Special NotationsIf the survey requirements related to maintenance ofspecial notations are not carried out as required, thesuspension or cancellation may be limited to thosespecial notations only.

1/1.2.4 Suspension of Class Includes:a Class is suspended for any use, operation,

loading condition or other application of any craft forwhich it has not been approved and which affects ormay affect classification or the structural integrity,quality or fitness for a particular use or service.

b If the periodical surveys required formaintenance of class are not carried out by the duedate and no Rule allowed extension has been granted,class will be suspended.

c If recommendations issued by the Surveyor arenot carried out within their due dates, class will besuspended.

d Class is suspended for any damage, failure,deterioration or repair that has not been completed asrecommended.

e If proposed repairs as referred to in 1/3.1.1have not been submitted to the Bureau and agreedupon prior to commencement, class may besuspended.

1/1.2.5 Cancellation of Classa If the circumstances leading to suspension of

class are not corrected within the time specified, thevessel's class will be canceled.

b A vessel's class is canceled immediately whena vessel proceeds to sea without having completedrecommendations which were required to be dealtwith before leaving port.

1/1.3 Classification Symbols

1/1.3.1 Class NotationCraft which have been built to the satisfaction of theSurveyors to the Bureau to the full requirements ofthis Guide, or equivalent, where approved by theCommittee for unrestricted ocean service, will beclassed and distinguished in the Record by thesymbols !!!!A1 HSC !!!!AMS indicating compliancewith the hull and machinery requirements of theGuide.

1/1.3.2 Special RequirementsCraft which have been built to the satisfaction of theSurveyors to the Bureau to the requirements ascontained in this Guide for special types of craft andwhich are approved by the Committee for restrictedservice will be classed and distinguished in theRecord by the symbols !!!!A1 HSC followed by theappropriate notation, namely Passenger Craft (A),Passenger Craft (B), Ro/Ro Passenger Craft (A),Ro/Ro Passenger Craft (B), Cargo Craft; the (A)


and (B) indicate a craft defined as a Category APassenger Craft, a Category B Passenger Craftrespectively in accordance with the InternationalCode of Safety for High Speed Craft. The notation“Cargo Craft” defines a vessel that is certified inaccordance with the IMO International Code ofSafety for High Speed Craft.

1/1.3.3 Special Purpose CraftSpecial purpose craft, which have been built to thesatisfaction of the Surveyors to the Bureau toarrangements and scantlings approved for theparticular purpose, where approved by the Committeefor the particular service will be classed anddistinguished in the Record by the symbols !!!!A1HSC followed by a description of the service forwhich special modifications to the Rules have beenapproved, e.g. Government Service etc.

1/1.3.4 Service Limitationsa Geographical Limitation Craft which have

been built to the satisfaction of the Surveyors to theBureau to special modified requirements for arestricted service, where approved by the Committeefor that particular service, will be classed anddistinguished in the Record by the symbols andnotations as described in 1/1.3.1, 1/1.3.2 and 1/1.3.3above, but the symbols and notations will either befollowed by or have included in them the appropriaterestricted service, e.g., Gulf of Mexico Service,Philippines Inter-Island Service, Coastal ServiceLess than 25 Miles, Harbor Service, etc.

b Significant Wave Height Craft which havebeen designed and built for limited service operationwith a significant wave height less than 4 m (13 ft)will be distinguished in the Record by the specialcomment. Specific significant wave height to be usedin the design is to be clearly indicated in operatingmanual for restriction of service.

1/1.3.5 Craft not Built under SurveyCraft not built under survey to this Bureau, but whichare submitted for classification, will be subjected to aspecial classification survey. Where foundsatisfactory and thereafter approved by theCommittee, they will be classed and distinguished inthe Record by the symbols and special notations asdescribed in 1/1.3.1 to 1/1.3.4 above, but the symbol!!!! signifying the survey during construction will beomitted.

1/1.3.6 Equipment SymbolThe symbol placed after the symbols of

classification, thus; !!!!Al , will signify that theequipment of anchors and cables of the craft is incompliance with the requirements of the Guide orwith the requirements corresponding to the servicelimitation noted in the craft’s classification, whichhave been specially approved for the limited service.

1/1.3.7 !!!!AMS SymbolsMachinery constructed and installed to thesatisfaction of the Surveyors to the Bureau to the fullrequirements of the Guide, when found satisfactoryafter trial and approved by the Committee, will beclassed and distinguished in the Record by thesymbols !!!!AMS.

1/1.3.8 AMS SymbolsMachinery which has not been constructed andinstalled under survey to this Bureau, but which issubmitted for classification, will be subjected to aspecial classification survey. Where foundsatisfactory and thereafter approved by theCommittee, the machinery will be classed anddistinguished in the Record by the symbols AMS.The symbol !!!! signifying the survey duringconstruction will be omitted.

1/1.3.9 ACCU or ABCU SymbolsThe automatic and remote-control systems are to bein accordance with the applicable requirements ofSection 4/11.

1/1.5 Application

1/1.5.1 Application LimitsThis Guide is applicable to high speed craft forcommercial or governmental use constructed of steel,

aluminum, or FRP and having LV / not less than2.36 (1.30) where L is as defined in 3/1.1 and V is asdefined in 3/8.1.1. Applicable craft type and lengthare as follows:

Vessel Type Applicable LengthMono-hull < 130 m (427 ft.)Multi-hull < 100 m (328 ft.)Surface Effects Ship (SES) < 90 m (295 ft.)Hydro Foil < 60 m (197 ft.)


The criteria contained in this Guide are meant to beapplicable to those features that are permanent innature and can be verified by plan review,calculation, physical survey or other appropriatemeans. Any statement in this Guide regarding anyother feature is to be considered as guidance to thedesigner, builder, owner, et al.

1/1.5.2 Direct Analysesa Required Analyses Direct analyses are

required in particular cases to demonstrate theadequacy of the structural design. When the length ofcraft constructed of steel or aluminum exceeds 61m(200 feet), when the length of craft constructed ofFRP exceeds 50m (164 feet) or when the operatingspeed (V) exceeds 50 knots, the design of the mainsupporting members of the hull (e.g. web frames anddeep girders supporting stiffened plating) is to bedemonstrated by the performance of suitable directanalyses.

Similarly for vessel designs having the length orspeed values exceeding the mentioned ones, asuitable direct analysis is to be performed todemonstrate the adequacy of the hull girder strength.(See also 3/6.1.1b and 3/6.3.1.)

The direct analyses are to be performed using anacceptable finite element method computer program.The extent of, and boundary conditions applied to,the analytical model(s) are to be appropriate to reflectadequately the behavior of the structure. The loads tobe applied to the structural model are to be based onconsideration of the design values; deck cargo andsimilar internal loads in the hull (accounting fordynamic effects as appropriate); the external pressureloads (see 3/8) and distribution specified in thisGuide; and appropriate wave induced hull girderbending moment and shear force effects. (Forexample see 3/6.1.)

b Supplementary Analyses In addition to thedirect analyses required in a above, the Bureau mayrequire the performance of additional direct analysesto demonstrate and document the adequacy of otherfeatures of the hull structural design, which areconsidered to be within the scope of classification.The need to provide such analyses can arise: in the

case of novel designs; where structural displacementis expected to influence (more than usually) structuralresponse; where hull propulsion or steering systemload transmission in the hull needs to be speciallyaddressed; to demonstrate the efficiency of novelconnection details on hull strength; etc.

For types of behavior or loading effects which arenot within the scope of classification of the vessel tobe classed, the Bureau will upon request provideadvice on what it feels constitutes an appropriateanalysis. Such analyses include those for vibrationand docking arrangements.

c Analysis Scope and Documentation Thescope, details and manner of documenting theanalyses are to be agreed with the Bureau before theanalyses are done.

1/1.5.3 Design by TestingWhere it is intended to use physical testing (e.g. tankmodel testing, etc.) as the primary or supplementarybasis of design, the details of such testing and theprocedures to be followed to establish design valuesare to be agreed to by the Bureau, prior to theperformance of the testing.

1/1.5.4 Alternativesa General The Committee is at all times ready to

consider alternative arrangements and scantlingswhich can be shown, through either satisfactoryservice experience or a systematic analysis based onsound engineering principles, to meet the overallsafety and strength standards of the Guide.

b National Standards The Committee willconsider special arrangements or details of hull,equipment or machinery which can be shown tocomply with standards recognized in the country inwhich the craft is registered or built, provided theyare not less effective.

c Other Rules The Committee will consider hull,equipment or machinery built to the satisfaction of theSurveyors to the Bureau in accordance with the plansthat have been approved to the Rules of anotherrecognized classification society with verification ofcompliance by the Bureau. A notation will be enteredin the Record indicating that classification hasincorporated the provisions of this subparagraph.Submission of plans is to be in accordance with1/1.11.

1/1.5.5 Novel FeaturesCraft which have novel features of design in respectof the hull, machinery or equipment to which theprovisions of this Guide are not directly applicablemay be classed, when approved by the Committee, onthe basis that this Guide insofar as applicable hasbeen complied with and that special consideration hasbeen given to the novel features based on the bestinformation available at the time.


1/1.5.6 Effective Date of Rule Changea Six Month Rule Changes to the Guide are to

become effective on the date specified by the Bureau.In general, the effective date is not less than sixmonths from the date of their publication. However,the Bureau may bring into force individual changesbefore that date if necessary or appropriate.

b Implementation of Rule Changes In general,until the effective date, plan approval for designs willfollow prior practice unless review under the latestGuide is specifically requested by the party signatoryto the application for classification. If one or morevessels are to be constructed from plans previouslyapproved, no retroactive application of the latestGuide changes will be required except as may benecessary or appropriate for all contemplatedconstruction.

1/1.7 Regulations

1/1.7.1 GeneralWhile the Guide covers the requirements for theclassification of new craft, the attention of Owners,designers, and builders is directed to the regulationsof international, governmental and other authoritiesdealing with those requirements in addition to or overand above the classification requirements.

1/1.7.2 International Conventions or CodesWhere authorized by the Administration of a countrysignatory thereto and upon request of the Owners of aclassed craft or one intended to be classed, theBureau will survey a new or existing craft forcompliance with the provisions of InternationalConventions or Codes including the following, andcertify thereto in the manner prescribed in theConvention or Code.

International Convention on Load Lines, 1966.International Convention for the Safety of Life at Sea,

1974, as amended.International Code for Safety for High Speed Craft

(HSC Code).International Convention on Tonnage Measurement

of Ships, 1969.International Convention for the Prevention of

Pollution from Ships, 1973/78, as amended.

1/1.7.3 International Code of Safety for HighSpeed Craft

Where authorized by the Administration of a countrysignatory to the SOLAS convention, and upon requestof the Owners of an existing craft or a craft underconstruction, the Bureau will review plans and surveythe craft for compliance with the provisions of theCode and certify thereto in the manner prescribed inthe Code. Builders and owners are advised thatAdministrations may have special interpretations ofthe requirements as given in the International Code ofSafety for High Speed Craft and they should contactthe Administration as to this at an early stage in thedesign.

1/1.7.4 Governmental RegulationsWhere authorized by a government agency and uponrequest of the owners of a classed craft or oneintended to be classed, the Bureau will survey andcertify a new or existing craft for compliance withparticular regulations of that government on theirparticular regulations of that government on theirbehalf.

1/1.9 IACS AuditThe International Association of ClassificationSocieties (IACS) conducts audits of processesfollowed by all its member societies to assess thedegree of compliance with the IACS Quality SystemCertification Scheme requirements. For this purpose,auditors from IACS may accompany ABS personnelat any stage of the classification or statutory workwhich may necessitate the auditors having access tothe craft or access to the premises of the manufactureror shipbuilder.

In such instances, prior authorization for theauditor's access will be sought by the local ABSoffice.

1/1.11 Submission of PlansHull and machinery plans, as required below, are tobe submitted to the Bureau for review and approval.Plans from designers and shipbuilders shouldgenerally be submitted in triplicate, one copy to bereturned to those making the submission, one copyfor the use of the Surveyor where the craft is beingbuilt, and one copy to be retained in the ABSTechnical office for record. Manufacturers plans areto be submitted in quadruplicate where construction isto be carried out at a plant other than that of theshipbuilder. However, additional copies may berequired when the required attendance of theSurveyor is anticipated at more than one location. Allplan submissions originating from manufacturers areunderstood to be made with the cognizance of theshipbuilder. A fee may be charged for the review ofplans for which there is no contract of classification.


1/1.11.1 Hull PlansPlans showing the arrangements, scantlings, details ofprincipal parts of the hull structure, and weldingdetails of each craft to be built under survey are to besubmitted and approved before construction iscommenced. These plans are to include suchparticulars as the design draft, displacement anddesign speed. Where provision is to be made for anyspecial type of cargo or for any exceptionalconditions of loading, particulars of the weights andof their distribution are also to be given. In generalthe following plans are to be submitted for review orreference.

Anchor handling arrangementsBottom construction, floors, girders, inner bottom

plating, etc.Bow framingCapacity planCraft SpecificationsDamage Control planDeck plansFraming planGeneral ArrangementHatches and hatch-closing arrangementsHull port and framing detailsLines and body planMachinery casings, engine and main auxiliary

foundationsMidship sectionMiscellaneous nontight bulkheads which are used as

structural supportsOperating manual and where applicable, maintenance

manual (see 3/6.9)Pillars and girdersScantling profile and decksShaft strutsShaft tunnelsShell expansionStemStern frame and rudderStern framingSuperstructure and deckhouses, and their closing

arrangementsThrough-hull penetrations for thrusters, stabilizers,

exhausts, and sea valvesVentilation systems on weather decksWatertight and deep-tank bulkheadsWatertight doors and framingWeathertight doors, framing, and sill heightsWelding Schedule and details, bonding details (FRP)Window and framing details

1/1.11.2 Machinery Plans and DataPlans and data required to be submitted to the Bureaufor review and approval are listed in 4/1.11.

1/1.11.3 Additional PlansWhere certification under 1/1.7.2 or 1/1.7.3 isrequested, submission of additional plans andcalculations may be required.

1/1.11.4 FRP Building Process Description andQuality Manual

For FRP structure, the builder is to submit a processdescription of the construction before the constructioncommences. Details of the information to besubmitted are given in Section 2/5.

1/1.13 Conditions for Surveys after Construction

1/1.13.1 Damage, Failure and Repaira Examination and Repair Damage, failure,

deterioration or repair to hull, machinery orequipment, which affects or may affect classification,is to be submitted by the Owners or theirrepresentatives for examination by a Surveyor at firstopportunity. All repairs found necessary by theSurveyor are to be carried out to the Surveyor’ssatisfaction.

b Repairs Where repairs to hull, machinery orequipment, which affect or may affect classification,are planned in advance to be carried out, a completerepair procedure including the extent of proposedrepair and the need for Surveyor's attendance is to besubmitted to and agreed upon by the Bureaureasonably in advance. Failure to notify the Bureau,in advance of the repairs, may result in suspension ofthe craft’s classification until such time as the repairis redone or evidence submitted to satisfy theSurveyor that the repair was properly carried out.Note: The above applies also to repairs during voyage.

The above is not intended to include maintenanceand overhaul to hull, machinery and equipment inaccordance with the recommended manufacturer'sprocedures and established marine practice and whichdoes not require Bureau approval; however, anyrepair as a result of such maintenance and overhaulswhich affects or may affect classification is to benoted in the ship's log and submitted to the Surveyoras required by 1/1.11.1a.

c Representation Nothing contained in thissection or in a rule or regulation of any governmentor other administration, or the issuance of any reportor certificate pursuant to this section or such a rule orregulation, is to be deemed to enlarge upon therepresentations expressed in 1/1.1.1 through 1/1.1.4hereof and the issuance and use of any such reports orcertificates are to be governed in all respects by1/1.1.1 through 1/1.1.4 hereof.


1/1.13.2 Notification and Availability for SurveyThe Surveyors are to have access to classed craft atall reasonable times. For the purpose of SurveyorMonitoring, monitoring Surveyors shall also haveaccess to classed craft at all reasonable times. Suchaccess may include attendance at the same time as theassigned Surveyor or during a subsequent visitwithout the assigned Surveyor. The Owners or theirrepresentatives are to notify the Surveyors on alloccasions when a craft can be examined in dry dockor on a slipway.

The Surveyors are to undertake all surveys onclassed craft upon request, with adequate notification,of the Owners or their representatives and are toreport thereon to the Committee. Should theSurveyors find occasion during any survey, torecommend repairs or further examination,notification is to be given immediately to the Ownersor their representatives in order that appropriateaction may be taken. The Surveyors are to availthemselves for every convenient opportunity forcarrying out periodical surveys in conjunction withsurveys of damages and repairs in order to avoidduplication of work.

1/1.13.3 Attendance at Port State RequestIt is recognized that Port State authorities legally mayhave access to a craft. In cooperation with PortStates, ABS Surveyors will attend on board a classedcraft when so requested by a Port State, and uponconcurrence by the craft's master will carry out asurvey in order to facilitate the rectification ofreported deficiencies or other discrepancies thataffect or may affect classification. ABS Surveyorswill also cooperate with Port States by providinginspectors with background information, if requested.Such information includes text of conditions of class,survey due dates, and certificate expiration dates.

Where appropriate, the vessel's flag state will benotified of such attendance and survey.

1/1.15 FeesFees in accordance with normal ABS practice will becharged for all services rendered by the Bureau.Expenses incurred by the Bureau in connections withthese services will be charged in addition to the fees.Fees and expenses will be billed to the partyrequesting that particular service.

1/1.17 Disagreement

1/1.17.1 GuideAny disagreement regarding either the properinterpretation of the Guide, Rules, or translation ofthis Guide from the English language edition, is to bereferred to the Bureau for resolution.

1/1.17.2 SurveyorsIn case of disagreement between the Owners orbuilders and the Surveyors regarding the material,workmanship, extent of repairs, or application of theGuide relating to any craft classed or proposed to beclassed by this Bureau, an appeal may be made inwriting to the Committee, who will order a specialsurvey to be held. Should the opinion of the Surveyorbe confirmed, the expense of this special survey is tobe paid by the party appealing.

1/1.19 Limitation of LiabilityThe combined liability of American Bureau ofShipping, its committees, officers, employees, agents,or subcontractors for any loss, claim, or damagearising from its negligent performance ornonperformance of any of its services or from breachof any implied or express warranty of workmanlikeperformance in connection with those services, orfrom any other reason, to any person, corporation,partnership, business entity, sovereign, country ornation, will be limited to the greater of a) $100,000 orb) an amount equal to ten times the sum actually paidfor the services alleged to be deficient.

The limitation of liability may be increased up toan amount twenty-five times that sum paid forservices upon receipt of Client's written request at orbefore the time of performance of services and uponpayment by Client of an additional fee of $10.00 forevery $1,000.00 in the limitation.

PART 1 SECTION 2|1 Testing and Trials During Construction-Hull

PART 1 SECTION 2

Testing and Trials During Construction-Hull

1/2.1 Tank, Bulkhead and Rudder TightnessTesting

1/2.1.1 GeneralAfter all hatches and watertight doors are installed,penetrations including pipe connections are fitted andbefore cement work or ceiling is applied over joints,all tanks and watertight bulkheads or flats are to betested and proven tight. Refer to Table 1/2.1 forspecific test requirements. Close visual examinationcombined with non-destructive testing may beaccepted in certain areas where specially approved, asan alternative to hose testing.

1/2.1.2 Hydrostatic TestingUnless air testing has been approved as an alternative,tanks are to be tested with a head of water to theoverflow or to the highest point to which the contentsmay rise under service conditions, whichever ishigher. This may be carried out before or after thevessel is launched. Special coatings may be appliedbefore hydrostatic testing provided all welding atjoints and penetrations is visually examined to thesatisfaction of the Surveyor before special coating isapplied.

Sliding watertight doors are to be tested with ahead of water equivalent to the height of the bulkheaddeck or freeboard deck at the maker’s works.

1/2.1.3 Air TestingWhere permitted in Table 1/2.1, air testing orcombined air testing and hydrostatic testing by anapproved procedure may be accepted unless thespecified test is deemed necessary by the Surveyor.Where air testing is adopted, all boundary welds,erection joints, and penetrations including pipeconnections are to be examined under the approvedtest procedure with a suitable leak indicator solutionprior to the application of special coatings. Air testpressure differential should normally be 0.137 bar(0.14 kgf/cm2, 2 psi). Means are to be provided toprevent accidental overpressuring of tanks duringtesting. Air-pressure drop testing, i.e. checking forleaks by monitoring drop in pressure, is not anacceptable substitute for required hydrostatic orair/soap testing.

1/2.1.4 Hose TestingHose testing is to be carried out under simultaneousinspection of both sides of the joint. The pressure inthe hose is not to be less than 2.06 bar (2.1 kgf/cm2,30 psi).

1/2.2 Tank Tests for Structural AdequacyIn order to demonstrate the structural adequacy,representative hydrostatic testing of tanks may berequired in connection with the approval of thedesign. In general this would include at least one tankof each type of new or unusual vessel or tank design.

1/2.3 Anchor Windlass TrialsEach anchor windlass is to be tested under normalworking conditions to demonstrate satisfactoryoperation. Each required anchor handling unit,independently, is to be tested for braking, clutchfunctioning, power lowering, hoisting, and properriding of the chain through the hawsepipe, over thewildcat (chain wheel), through the chain pipe, andstowing in the chain locker. Also, it is to bedemonstrated that the windlass is capable of liftingeach anchor with 82.5m (45 fathoms) length of chainsubmerged and hanging free. Where the availablewater depth is insufficient, the proposed test methodwill be specially considered.

1/2.4 Bilge System TrialsAll elements of the bilge system are to be tested todemonstrate satisfactory pumping operation,including emergency suctions and all controls. Uponcompletion of the trials, the bilge strainers are to beopened, cleaned and closed up in good order.

1/2.5 Steering TrialsRefer to Section 4/8.8.2 for the technical details ofthe steering trials.

1/2.6 Construction Welding and FabricationFor surveys of hull construction welding andfabrication, refer to Section 2/3 and the ABS "Rulesfor Nondestructive Inspection of Hull Welds".

1/2.7 Hull Castings and ForgingsFor surveys in connection with the manufacture andtesting of hull castings and forgings, refer to Section2/1.

PART 1 SECTION 2|2 Testing and Trials During Construction-Hull

1/2.8 PipingFor surveys in connection with the manufacture andtesting of piping, refer to Section 4/6.

TABLE 1/2.1Initial Tank, Bulkhead andRudder Tightness Testing

Requirements

Item Test Method

Double Bottom Tanks Hydro Test *Deep Tanks Hydro Test *Forepeak & Afterpeak Tanks Hydro Test *Ballast Tanks, Cargo Craft Hydro Test *Forepeak Dry Space Hose Test *Duct Keels Hydro Test *Shaft Tunnels (clear of deep

tanks)Hose Test

Chain Lockers (aft of fore peakbulkhead)

To be filled with water

Hawse Pipes Hose TestWeathertight Hatchcovers &

Water/Weathertight ClosingAppliances

Hose Test

Watertight Bulkheads & Flats Hose Test *Void Space Boundaries Required

to be WatertightHose Test *

Double Plate Rudders and Skegs Hydro Test *

Note: Air test or combined air and hydrostatic testing may beaccepted for those items marked (*) under the conditionsspecified in 1/2.1.3. Such test may also be considered forother items where hydrotest is impracticable.

PART 2

Materials and Welding

The independent booklets, “Rule Requirements for Materials and Welding – Part 2” for steels,irons, bronzes, etc. and “Requirements for Materials and Welding Part 2 - Aluminum, - FiberReinforced Plastics (FRP)” are to be referred to. Each booklet consists of the followingChapters/Sections:

Rule Requirements for Materials and Welding

CHAPTER*1 Materials for Hull Construction and Equipment2 Materials for Equipment3 Materials for Machinery, Boilers, Pressure Vessels and Piping4 Welding and Fabrication

Part A - Hull ConstructionPart B - Boilers, Unfired Pressure Vessels, Piping and Engineering StructuresPart C - Weld Test

Appendices*1 List of Destructive and Nondestructive Tests Required in Sections 2/1 and 2/2,

and Responsibility for Verifying2 Requirements for Approval of Filler Metals3 Application of ABS Filler Metals to ABS Steels

Requirements for Materials and Welding - Aluminum- Fiber Reinforced Plastics (FRP)

SECTION

4 Materials for Hull Construction - Aluminum5 Materials for Hull Construction - Fiber Reinforced Plastics (FRP)

Appendix2/E Aluminum Welding in Hull Construction

* The original Sections 1 through 3 have been replaced by Chapters 1 through 4. Also,the original Appendices 2/A through 2/C have been replaced by the Appendices 1through 3, with Appendix 2/D having been removed.

PART 3

Contents

Hull Construction and Equipment

SECTION

1 Definitions2 General3 Subdivision and Stability4 Keels, Stems, and Shaft Struts5 Rudders6 Primary Hull Strength8 Design Pressures9 Plating

10 Internals12 Hull Structural Arrangement14 Arrangement, Structural Details and Connections18 Protection of Deck Openings20 Bulwarks, Rails, Ports, Portlights, Windows, and Ventilators21 Protective Coatings22 Equipment23 Welding, Forming, and Weld Design24 Fire Safety Measures

Appendices3/A Guidelines in Calculating Bending Moment and Shear Force in Rudders and

Rudder Stocks3/B Guidance on Torsional Analysis of the cross Deck Structure of a Multi-Hull

Craft3/C Guidance on First Ply Failure Analysis on FRP Sandwich Panels

PART 3 SECTION 1|1 Definitions

PART 3 SECTION 1

Definitions

The following definitions of terms are to beunderstood (in the absence of other specifications)where they appear in the Guide.

3/1.1 LengthL is the distance in meters or feet on the summer loadline, or if applicable, the design load waterline in thedisplacement mode, from the fore side of the stem tothe centerline of the rudder stock. For use with theGuide, L is not to be less than 96% and need not begreater than 97% of the length on the summer loadline, The forward end of L is to coincide with theforeside of the stem on the waterline on which L ismeasured.

3/1.3 BreadthB is the greatest molded breadth in meters or feet.

3/1.5 DepthD is the molded depth in meters or feet, measured atthe middle of the length L, from the molded keel lineto the top of the freeboard deck beams at the side ofthe craft. On craft with rabbeted keel construction, Dis to be measured from the rabbet line, In cases wherewatertight bulkheads extend to a deck above thefreeboard deck and are to be recorded in the Record aseffective to that deck, D is to be measured to thebulkhead deck,

3/1.7 Draft for Scantlingsd is the draft, in meters or feet, measured at the middleof the length L from the molded keel or the rabbet lineat its lowest point to the estimated summer loadwaterline or the design load waterline in thedisplacement mode, whichever is greater.

3/1.9 Freeboard DeckThe freeboard deck is normally the uppermostcontinuous deck having permanent means forweathertight closing of all openings in its weatherportions, and below which all openings in the craftside are equipped with permanent means for watertightclosure. In cases where a craft is designed for aspecial draft considerably less than that correspondingto the least freeboard obtainable under theInternational Load Line Regulations, the freeboarddeck for the purpose of the Rules may be taken as thelowest actual deck from which the draft can beobtained under those regulations.

3/1.11 Bulkhead DeckThe bulkhead deck is the highest deck to whichwatertight bulkheads extend and are made effective.

3/1.13 Strength DeckThe strength deck is the deck which forms the top ofthe effective hull girder at any part of its length. SeeSection 3/6.

3/1.15 Superstructure DeckA superstructure deck is a deck above the freeboarddeck to which the side shell plating extends or ofwhich the sides are fitted inboard of the hull side notmore than 4% of the breadth, B. Except whereotherwise specified the term superstructure deck whereused in the Guide refers to the first such deck abovethe freeboard deck

3/1.16 SuperstructureA superstructure is an enclosed structure on the mainweather deck having side plating as an extension of theshell plating, or not fitted inboard of the hull side morethan 4% of the breadth B.

3/1.17 DeckhousesA deckhouse is an enclosed structure above thefreeboard deck, having side plating set inboard of thehull side-shell plating more than 4% of the breadth Bof the craft.

3/1.18 DisplacementThe displacement ∆, is the mass displacement of thevessel in the design condition in metric tons (longtons), unless otherwise specifically noted.

3/1.19 Gross TonnageThe measurement of the internal volume of spaceswithin the craft as defined by the InternationalConvention on Tonnage Measurement of Ships, 1969.

3/1.20 Significant Wave HeightSignificant wave height is the average height of theone-third highest observed wave heights over a givenperiod.


3/1.21 SpeedSpeed is the design speed in knots with the craftrunning ahead at the maximum continuous rated shaftrpm and at the summer load waterline. Operationalspeed is 90% of design speed.

3/1.22 Rabbet Line (Fiber Reinforced Plastic)The rabbet line is the line intersection between theoutside of a craft’s bottom and a craft’s keel. Wherethere is no keel, the rabbet line is the bottom of thecraft.

3/1.23 AdministrationThe government of the state whose flag the craft isintended to fly.

3/1.25 Passenger CraftAny craft which carries more than twelve passengers.See also 5/1.3.

3/1.27 Cargo CraftAny craft other than a passenger craft, which iscapable of maintaining the main functions of safetysystems of unaffected spaces after damage in any onecompartment on board.

3/1.29 PassengerA passenger is every person other than the master andmembers of the crew or other persons employed orengaged in any capacity on board a craft on thebusiness of that craft, and a child under one year ofage.

3/1.31 Place of RefugeAny naturally or artificially sheltered area which maybe used as shelter by a craft under conditions likely toendanger its safety.

3/1.33 Fiber-Reinforced Plastic (FRP)

FRP consists of two basic components: a glass-filament or other material fiber reinforcement and aplastic, or resin, in which the reinforcing material isimbedded.

3/1.33.1 ReinforcementReinforcement is a strong, inert material bonded intothe plastic to improve its strength, stiffness and impactresistance. Reinforcements are usually fibers of glass(a lime-alumina-silicate composition having a lowalkali content) or other approved material such asaramid or carbon fiber, in a woven or non-wovenform, with a strong adhesive bond to the resin.

a Strand A bundle of continuous filamentscombined in a single, compact unit.

b Roving A band or ribbon of parallel strandsgrouped together.

c Yarn A twisted strand or strands suitable forweaving into a fabric.

d Binder A polyester applied in small quantitiesto fibers to hold them together in mat form.

e Coupling Agent An active water solublechemical that allows resin to adhere to glass,

f Chopped-strand Mat A blanket of randomlyoriented chopped-glass strands held together withbinder.

g Woven Roving A coarse fabric woven fromrovings.

h Cloth A fabric woven from yarni Peel-Ply An "E" glass fabric that does not have

any coupling agent applied, used as a protectivecovering on a laminate being prepared for a secondarybond to keep foreign particles from adhering to thesurface.

j Uni-directional A woven or non-wovenreinforcement with substantially more fibers in oneprincipal axis of the reinforcing ply.

k Double Biased A woven or non-wovenreinforcement with fibers primarily at + 45° to theprincipal axes of the reinforcing ply.

l Knitted or Stitched Fabrics Two or more layersof unidirectional fabrics that are stitched together.

m Bi-axial Fabric A stitched or knittedreinforcement with fibers primarily in the principalaxis of the reinforcing ply.

n Tri-axial Fabric A stitched or knittedreinforcement with fibers running in one principal axisof the ply and in addition, with fibers running at + and-45° to the warp.

o Ply Principal Axes The two principal axes of areinforcing ply are the axis that is parallel to the warpand the axis that is parallel to the fill.

p Warp The roving or yarn running lengthwise inwoven fabric (in the “roll direction”).

q Fill, Weft or Woof The roving or yarn runningat right angles to the warp in a woven fabric.

r “E” glass A family of glass reinforcementmaterial of aluminoborosilicate composition andhaving high electrical resistivity.

s “S” glass A family of glass reinforcementmaterial of magnesium aluminosilicate compositionthat contains a higher silicon content and provideshigher strength and stiffness properties than “E” glass.

t Kevlar An aramid fiber reinforcement.u Carbon Fiber A reinforcement material made

of mostly carbon produced by the pyrolysis of organicprecursor fibers in an inert environment.

3/1.33.2 ResinResin is a highly reactive synthetic that in its initialstage is a liquid, but upon activation is transformedinto a solid.

a Accelerator A material that, when mixed withresin, speeds the cure time.


b Additive A substance added to anothersubstance, usually to improve properties, such asplasticizers, initiators, light stabilizers and flameretardants.

c Catalyst or Initiator A material that is used toactivate resin, causing it to harden.

d Crazing Hairline cracks, either within or on thesurface of resin, caused by mechanical or thermalstresses.

e Cure To change resin from a liquid to a solid.f Cure time The time required for resin to change

from a liquid to a solid after a catalyst has been added.g Exothermic Heat The heat given off as the

result of the action of a catalyst on resin.h Filler A material added to resin to modify its

working properties or other qualities, or to lower costs.i Gel A partially cured resin in a semi-solid state

similar to gelatin in consistency.j Gel Time The time required to change a

flowable, liquid resin into a nonflowing gel.k Inhibitor A material that retards activation or

initiation of resin, thus extending shelf life orinfluencing exothermic heat or gel time.

l Polymerization The reaction that takes placewhen resin is activated or initiated.

m Pot Life The length of time that a catalyzedresin remains workable.

n Shelf Life The length of time that anuncatalyzed resin maintains its working propertieswhile stored in a tightly sealed, opaque container.

o Tack The degree of stickiness of the resin.p Thixotropy The property or phenomenon,

exhibited by some resins, of becoming jelly-like at restbut becoming fluid again when stirred or agitated.This facilitates the application of the resin to inclinedor vertical surfaces.

q Polyester Resin A thermosetting resin that isformed by combining saturated and unsaturatedorganic acids. Such as otrhophthalic and isophthalicacids.

r Vinylester Resin A thermosetting resin thatconsists of a polymer chain and an acrylate ormethacrylate termination.

s Epoxy A resin that contains one or more of theepoxide groups.

3/1.33.3 LaminateA laminate is a material composed of successivebonded layers, or plies, of resin and fiber or otherreinforcing substances.

a Bi-directional Laminate A laminate havingessentially the same strength and elastic properties inthe two in plane principal axes. Bi-directionallaminates may be constructed of bi-axial, double bias,tri-axial, mat or unidirectional reinforcing layers, or acombination of any of these.

b Uni-directional Laminate A laminate withsubstantially more of the fibers in the plane of thelaminate oriented in one of the two principal axis ofthe laminate plane so that the mechanical propertiesalong that axis are appreciably higher than along theother natural axis.

c Sandwich Laminate A laminate consisting oftwo fiber reinforced plastic skins attached to a non-structural or structural core (see 3/1.33.4Encapsulation),

d Barcol Hardness A measurement of thehardness of a laminate and thereby the degree ofcompletion of the cure.

e Delamination The separation of the layers ofmaterial in a laminate.

f Gel Coat The first resin applied to mold whenfabricating a laminate to provide a smooth protectivesurface for the laminate.

g Layup The process of applying to a mold thelayers of resin and reinforcing materials that make up alaminate. These materials are then compressed ordensified with a roller or squeegee to eliminateentrapped air and to spread resin evenly. Also adescription of the component materials and geometryof a laminate.

h Peel Ply A partially impregnated, lightlybonded layer of glass, cloth or woven roving used toprotect a laminate in anticipation of secondarybonding, providing a clean, fresh bonding surface.

i Secondary Bonding The practice of bondingfresh material to a cured or partially cured laminate.

j Verified Minimum Mechanical Property Themechanical properties, in 2/5, of laminates differingfrom the basic, verified by the appropriate test(s) listedin Table 2/5.1.

k Laminate Principal Axes The two principalaxes of a square or rectangular plate panel are for theapplication of this Guide those perpendicular andparallel to the plate panel edges.

1 Vacuum Bagging A method used to apply auniform pressure over an area by applying a vacuum tothat area.

m Resin Impregnation A process of constructionfor large layers of fabric that consists of running a rollof fabric through a resin bath to completely saturatethe fabric.

n Resin Transfer Molding A closed mold methodthat mechanically pumps resin through dry fabricpreviously placed in the mold.

o Resin Infusion A method of FRP constructionthat uses a vacuum (from a vacuum bag) to pullcatalyzed resin through dry fabric.

p Primary Bond The bond that is formed betweentwo laminated surfaces when the resin on both surfaceshas not yet cured.

q Secondary Bond The bond that is formedbetween two laminated surfaces when the resin on oneof the two surfaces has cured.


r Post Cure The act of placing a laminate in anautoclave and raising the temperature to assist in thecure cycle of the resin.

s Autoclave A large oven used in post curinglarge laminated parts.

3/1.33.4 EncapsulationThe containment of a core material such as softwoods,plywood, balsa, PVC (cross linked), or linear polymerwithin FRP laminates. The cores may be structurallyeffective or ineffective.

a Bedding Putty Material used to adhere the corematerial to the FRP skins.

b Scores Slits cut into the core material to aid informing the core to complex shapes.

3/1.35 UnitsThese Rules are written in three systems of units SIunits, MKS units and US customary units. Eachsystem is to be used independently of any othersystem.

The format of presentation in the Guide of thethree systems of units is as follows:

SI units (MKS units, US customary units)

unless indicated otherwise.

PART 3 SECTION 2|1 General

PART 3 SECTION 2

General

3/2.1 MaterialsThis Guide is intended for welded craft constructed ofsteel, welded craft constructed of aluminum, and fiberreinforced plastic (FRP) craft; complying with therequirements of section 2/1, 2/4, and 2/5 respectively.The use of materials other than those specified in 2/1,2/4, and 2/5 and the corresponding scantlings will bespecially considered.

3/2.1.1 Selection of Material Grade

For craft 61 m (200 ft) and over in length, steelmaterials are not to be lower grades than thoserequired by Table 3/2.1b for the material class givenin Table 3/2.1a for the particular location.

3/2.1.2 Note for the Users

The attention of users is drawn to the fact that, whenfatigue loading is present, the effective strength ofhigher-strength steel in a welded construction may notbe greater than that of ordinary-strength steel.Precautions against corrosion fatigue may also benecessary.

3/2.3 WorkmanshipAll workmanship is to be of commercial marinequality and acceptable to the Surveyor. Welding is tobe in accordance with the requirements of Sections2/3, 2/E and 3/23.

3/2.5 Design

3/2.5.1 ContinuityCare is to be taken to provide structural continuity.Changes in scantlings are to be gradual. Strengthmembers are not to change direction abruptly. Whereprimary structural members terminate at anotherstructural member, tapering of the primary membermay be required beyond the other structural member.Stanchions and bulkheads are to be aligned to providesupport and to minimize eccentric loading. Majorappendages outside the hull and strength bulkheads insuperstructures are to be aligned with major structuralmembers within the hull

3/2.5.2 OpeningsThe structural arrangements and details are to be inaccordance with Section 3/14. In general, majoropenings such as doors, hatches, and large vent ductsare to be avoided in the hull in close proximity to thegunwale. Corners of openings in strength structuresare to have generous radii. Compensation may berequired for openings.

3/2.5.3 Bracketsa Steel Brackets Where brackets are fitted having

thicknesses as required by Table 3/2.1 and faces atapproximately 45 degrees with the bulkhead deck orshell and the bracket is supported by a bulkhead, deckor shell structural member, the length of eachmember, l, may be measured at a point 25% of theextent of the bracket beyond the toe of the bracket asshown in Figure 3/2.1. The minimum overlap of thebracket arm along the stiffener is not to be less thanobtained from the following equation.

x = 1.4y +30 mm x = 1.4y + 1.2 in.

x = length of overlap along stiffener in mm or in.y = depth of stiffener in mm or in.

Where a bracket laps a member, the amount ofoverlap generally is to be 25.5 mm (1 in.).

b Aluminum Brackets Aluminum brackets areto comply with 3/2.5.3a except that the thicknessesgiven in Table 3/2.1 are to be multiplied by 1.45 forthe same length of face.

3/2.5.4 Structural Design DetailsThe designer is to give consideration to the following:

a The thickness of internals in locationssusceptible to rapid corrosion.

b The proportions of built-up members to complywith established standards for buckling strength.

c The design of structural details such as notedbelow, against the harmful effects of stressconcentrations and notches:

1 Details of the ends, the intersections ofmembers and associated brackets.

2 Shape and location of air, drainage orlightening holes.

3 Shape and reinforcement of slots or cut-outs for internals.


4 Elimination or closing of weld scallops inway of butts, “softening” of bracket toes,reducing abrupt changes of section orstructural discontinuities.

d Proportions and thickness of structuralmembers to reduce fatigue response due to engine,propeller or wave-induced cyclic stresses, particularlyfor higher-strength steels.Standard construction details based on the aboveconsiderations are to be indicated on the plans or in abooklet submitted for review and comment.

3/2.5.5 Termination of Structural MembersUnless permitted elsewhere in the Guide, structuralmembers are to be effectively connected to theadjacent structures in such a manner to avoid hardspots, notches and other harmful stressconcentrations. Where members are not required tobe attached at their ends, special attention is to begiven to the end taper, by using soft-toed concavebrackets or by a sniped end of not more than 30°.Bracket toes or sniped ends are to be kept within 25mm (1.0 in.) of the adjacent member and the depth atthe toe or snipe end is generally not to exceed 15 mm(0.60 in.). Where a strength deck or shell longitudinalterminates without end attachment it is to extend intothe adjacent transversely framed structure or stop at alocal transverse member fitted at about one transverseframe space beyond the last floor or web thatsupports the longitudinal.

3/2.7 Effective width of platingThe section modulus and moment of inertia ofstiffening members are provided by the member and aportion of the plating to which it is attached. Theeffective width is as given in the following sub-sections. The section modulus and moment of inertiaof a shape, bar, fabricated section, or layed-upmember not attached to plating is that of the memberonly.

3/2.7.1 FRP LaminatesWhere the plating is an FRP single-skin laminate, themaximum effective width of plating for floors,frames, beams and bulkhead stiffeners is not toexceed either the stiffening member spacing or thewidth obtained from the following equation,whichever is less. See Figure 3/2.2.

w = 18t + b

where:w = effective width of plating in mm or in.t = thickness of single skin plating in mm or in.b = net width of stiffening member in mm or in.,

but not more than 18t

Where the plating is an FRP sandwich laminate with aflexurally and compressively ineffective (balsa, crosslinked PVC, or linear polymer) core, t in the aboveequation is the thickness of a single skin laminatehaving the same moment of inertia per unit width asthe two skins of the sandwich about the neutral axisof the sandwich, excluding the core.

For a stiffening member along an opening, themaximum effective width of plating is equal to eitherone-half the stiffening member spacing or the widthobtained from the following equation, whichever isless.

w = 9t + b

where w, t and b are as defined above.

3/2.7.2 Steel and Aluminum Platinga Primary Structural Members The effective

width of plating for deep supporting members is toequal to the lesser of either one half the sum ofspacing on each side of the member, 0.33 time theunsupported span, l, or 750mm (30 in). For girdersand webs along hatch openings the effective width ofplating is to be half of that obtained from the above.Due account is to be taken in regards to platebuckling, see 3/9.1.1

b All Other Structural Members The maximumeffective width of plating is equal to either one-halfthe sum of spacing on each side of the member or thewidth obtained from the following equation,whichever is less.

Steel Members: w = 80t

Aluminum Members: w = 60t

w = effective width of plating in mm or in.t = thickness of single skin plating in mm or in.

For a stiffening member along an opening, themaximum effective width of plating is one-half of theeffective width given above.


TABLE 3/2.1aMaterial Class of Structural Members

Structural memberWithin 0.4LAmidships

Outside 0.4LAmidships

Material Class (1)

or GradeMaterial Class

or GradeShellBottom plating including keel plateBilge strakeSide platingSheer strake at strength deck (5)

Class IIClass III (2),(3)

Class IClass III (3)

Grade A(7)/AHClass II (4)


DecksStrength deck plating (6)

Stringer plate in strength deck (5)

Strength deck plating within line ofhatches, and exposed to weather ingeneral

Class IIClass III (3)

Class I


Grade A(7)/AH

Longitudinal BulkheadLowest strake in single bottom vesselsUppermost strake including that of the

top wing tank

Class I

Class II

Grade A(7)/AH

Grade A(7)/AH

Other Structures in GeneralExternal continuous longitudinal

members (excluding longitudinal hatchcoamings) and bilge keels

Stern frames, rudder horns, rudders,and shaft brackets

Strength members not referred to inabove categories and above localstructures

Class II

–

Grade A(7)/AH

Grade A(7)/AH

Class I

Grade A(7)/AH

Notes1 Special consideration will be given to vessels in restricted service.

2 May be class II in vessels with a double bottom over the full breadth B.3 Single strakes required to be of material class III or E/EH are to have breadths not less than

800 + 5L mm (31.5 + 0.06L in.), but need not exceed 1800 mm (71 in.).4 May be class I outside 0.6L amidships.5 A radius gunwale plate may be considered to meet the requirements for both the stringer

plate and the sheerstrake, provided it extends a suitable distance inboard and vertically. Forformed material see 2-4-1/3.13

6 Plating at the corners of large hatch openings, is to be specially considered.7 ASTM A36 steel otherwise tested and certified to the satisfaction of ABS may be used in

lieu of Grade A for a thickness up to and including 12.5 mm (0.5 in.) for plate and up to andincluding 40 mm (1.57 in.) for sections.


TABLE 3/2.1bMaterial Grades

Material ClassThickness tmm (in.) I II III

t ≤ 15 (t ≤ 0.60) A(2), AH A, AH A, AH

15 < t ≤ 20 (0.60 < t ≤ 0.79) A, AH A, AH B, AH

20 < t ≤ 25 (0.79 < t ≤ 0.98) A, AH B, AH D, DH

25 < t ≤ 30 (0.98 < t ≤ 1.18) A, AH D, DH D (1), DH

30 < t ≤ 35 (1.18 < t ≤ 1.38) B, AH D, DH E, EH

35 < t ≤ 40 (1.38 < t ≤ 1.57) B, AH D, DH E, EH

40 < t ≤ 51 (1.57 < t ≤ 2.00) D, DH E, EH E, EH

Notes1 Grade D, of these thicknesses, is to be normalized.

2 ASTM A36 steel otherwise tested and certified to thesatisfaction of ABS may be used in lieu of Grade A for athickness up to and including 12.5 mm (0.5 in.) for plateand up to and including 40 mm (1.57 in.) for sections.

FIGURE 3/2.1Bracket

TABLE 3/2.1Brackets (Steel)

ThicknessLength of Face f, mm Millimeters Width of Flange, mm

Plain FlangedNot exceeding 305 5.0 --- --Over 305 to 455 6.5 5.0 38Over 455 to 660 8.0 6.5 50Over 660 to 915 11.0 8.0 63Over 915 to 1370 14.0 9.5 75

ThicknessLength of Face f, in. Inches Width of Flange, in.

Plain FlangedNot exceeding 12 3/16 -- --Over 12 to 18 1/4 3/16 1 ½Over 18 to 26 5/16 1/4 2Over 26 to 36 7/16 5/16 2 ½Over 36 to 54 9/16 3/8 3


FIGURE 3/2.2Effective Width of FRP Plating

PART 3 SECTION 3|1 Subdivision and Stability

PART 3 SECTION 3

Subdivision and Stability

3/3.1 GeneralCraft of the following categories are to havesubdivision and stability in accordance with thecriteria as shown.

3/3.3 Criteria

3/3.3.1 Intact StabilityAll craft which have a length of 24 m (79 ft) or overas defined in the International Convention on LoadLines are to have intact stability guidance as requiredby Regulation 10 of the International Convention onLoad Lines. Following criteria may be used forclassification purposes:

a For all cargo craft ≥ 500 GT making voyagesthat are no more than 8 hours at operational speedfrom a place of refuge and having design speedsgreater than 3.7∇ 1/6m/sec (7.19∇ 1/6 knots, 3.97∇ 1/6

knots) – IMO International Code of Safety for High-Speed Craft – Chapter 2

b For all passenger craft making voyages that areno more than 4 hours at operational speed from aplace of refuge and having design speeds greater than3.7∇ 1/6m/sec (7.19∇ 1/6 knots, 3.97∇ 1/6 knots) – IMOInternational Code of Safety for High-Speed Craft –Chapter 2

c Other craft of all sizes – IMO ResolutionA167/A206 with A562

where∇ = the volumetric displacement of the vessel in

the design condition in m3 (m3, ft3)GT = the gross tonnage as defined in 3/1.19

In case the above criteria are not applicable to aparticular craft, the intact stability will be reviewedby the Bureau in accordance with other recognizedcriteria appropriate to the craft's type, size, andintended service.

3/3.3.2 Subdivision and Damage StabilityCraft of applicable size, type, and service are to havesubdivision and damage stability as required by theInternational Code of Safety for High-Speed Craft, orthe International Convention for the Safety of Life atSea, 1974, as amended as follows:

a Passenger craft making voyages that are nomore than 4 hours at operational speed and havingdesign speeds greater than 3.7∇ 1/6m/sec (7.19∇ 1/6

knots, 3.97∇ 1/6 knots) – IMO International Code ofSafety for High-Speed Craft – Chapter 2

b Other passenger craft – SOLAS RegulationII-1/4 through 8

c Cargo craft ≥ 500 GT making voyages that areno more than 8 hours at operation speed and havingdesign speeds greater than 3.7∇ 1/6m/sec (7.19∇ 1/6

knots, 3.97∇ 1/6 knots) – IMO International Code ofSafety for High-Speed Craft – Chapter 2

d Other cargo craft ≥ 500 GT – SOLASRegulation II-1/25-1 through 25-8

3/3.5 Review Procedures

3/3.5.1 Administration ReviewWhen the craft is issued an International Load LineCertificate, Passenger Ship Safety Certificate, CargoShip Safety Construction Certificate, or High SpeedCraft Safety Certificate by the flag Administration orits agent other than the Bureau, such Certificate willbe accepted as evidence that the craft has subdivisionand stability in accordance with the above criteria.

Where the Administration undertakes the reviewof subdivision and stability and the Bureau is issuingthe above Certificate, the acceptance of subdivisionand stability by the Administration will be requiredbefore the certificate is issued.

3/3.5.2 Bureau ReviewIn all other cases the information and calculations forsubdivision and stability are to be submitted to theBureau for review. Where the intact stability criteriaare not applicable to a particular craft, the review willbe in accordance with other recognized criteriaacceptable to the Bureau.

PART 3 SECTION 4|1 Keels, Stems, and Shaft Struts

PART 3 SECTION 4

Keels, Stems, and Shaft Struts

3/4.1 Materials

3/4.1.1 Ordinary Strength SteelsThe requirements in the following subsections arebased upon ordinary strength steel. For higherstrength steels and aluminum alloys see 3/4.1.3.

3/4.1.3 High Strength Steels and AluminumAlloys

Unless otherwise specified, the required sectionmodulus and inertia for high strength steels andaluminum alloys are as follows:

SM = SMs QI = Is Es / Eo

SM,I = required section modulus and inertia.Unless specifically stated otherwise,the properties about the minor axis(axis perpendicular to h or w) are to beused.

SMs, Is = Section modulus and inertia obtainedfrom the dimensions given for ordinarystrength steel.

Q = as defined in 3/6.1.1aEs = 2.06 x 105 N/mm2 (21 x 103 kgf/mm2,

30 x 106 psi)Eo = modulus of the material being

considered in N/mm2 (kgf/mm2, psi)

Use of materials other than steel or aluminum will bespecially considered.

3/4.1.5 Fiber Reinforced PlasticFor fiber reinforced plastic hulls, keels and skegs areto have proportions as indicated in Figure 3/14.10and Figure 3/14.11.

3/4.2 Keels

3/4.2.1 Bar KeelsWhere bar keels are fitted the thickness and depth isnot to be less than obtained from the followingequations.

t = 0.625L + 12.5 mm t = 0.0075L + 0.50 in.h = 1.46L + 100 mm h = 0.0175L + 4 in.

t = thickness in mm or in.h = depth in mm or in.

L = length of craft in m or ft as defined inSection 3/1

Thicknesses and depths other than given above areacceptable provided the section modulii and momentsof inertia about the transverse horizontal axis are notless than given above, nor h/t more than 4.5.

3/4.2.2 Plate KeelsThe thickness of the steel plate keel throughout thelength of the craft is to be not less than the bottomshell required in 3/9.

3/4.4 Stems

3/4.4.1 Bar StemsWhere bar stems are fitted the thickness and depth isnot to be less than obtained from the followingequations.

t = 0.625L + 6.35 mm t = 0.0075L + 0.25 in.w = 1.25L + 90 mm w = 0.015L + 3.5 in.

t = thickness in mm or in.w = width in mm or in.L = length of craft in m or ft as defined in

Section 3/1

This thickness and width is to be maintained betweenthe keel and design load waterline. Above thedesigned load waterline they may be graduallyreduced until the area at the head is 70% of thatobtained from the equations.

Thicknesses and widths other than given aboveare acceptable provided the section modulii andmoments of inertia about the longitudinal axis are notless than above, nor w/t more than 5.5. The thicknessof the bar stem in general should also not be less thantwice the shell thickness.

3/4.4.3 Plate StemsWhere plate stems are used, they are not to be less inthickness than the bottom shell plating required in3/9.1 and 3/9.3, where s is the frame spacing, or 610mm (24 in.) if greater. Plate stems are to be suitablystiffened.

PART 3 SECTION 4|2 Keels, Stems, and Shaft Struts

3/4.6 Stern FramesCraft that are fitted with stern frames, shoe pieces,rudder horns, and rudder gudgeons are to meet theapplicable requirements in 3/4 of the Rules forBuilding and Classing Steel Vessels.

3/4.18 Shaft Struts

3/4.18.1 GeneralTail-shaft (propeller-shaft) struts where provided maybe of the V or I type. The thickness of the strut barrelor boss is to be at least one-fifth the diameter of thetail shaft. The length of the strut barrel or boss is tobe adequate to accommodate the required length ofpropeller-end bearings. The following equations arefor solid struts having streamline cross-sectionalshapes. For struts other than ordinary strength steelsee 3/4.1. For hollow section and non-streamlinedstruts, the equivalent cross sectional area, inertia, andsection modulus (about the major axis) are not to beless than required by 3/418.2 and 3/418.3. For astreamlined cross-section strut, the inertia about thelongitudinal axis is wt3/25 and the section modulusabout the same axis is wt2/12.5.

3/4.18.2 V Struta Width The width of each streamlined section

strut arm is not to be less than obtained from thefollowing equation.

w = 2.27d

w = width of strut (major axis) in mm or in.d = required diameter of ABS Grade 2 tail shaft

in mm or in. (see Section 4/7)

b Thickness The thickness of each streamlinedsection strut arm is not to be less than obtained fromthe following equation.

t = 0.365d

t = thickness of strut (minor axis) in mm or in.d = required diameter of ABS Grade 2 tail shaft

in mm or in.

Where the included angle is less than 45 degrees, theforegoing scantlings are to be specially considered.

3/4.18.3 I Struta Width The width of the streamlined section

strut arm is not to be less than obtained from thefollowing equation.

w1 = 3.22d

w1 = width of strut (major axis) in mm or in.d = diameter of tail shaft in mm or in.

b Thickness The thickness of the streamlinedsection strut arm is not to be less than obtained fromthe following equation.

t1 = 0.515d

t1 = thickness of strut (minor axis) in mm or in.d = diameter of tail shaft in mm or in.

3/4.18.4 Strut LengthThe length of the longer leg of a V strut or the leg ofan I strut, measured from the outside perimeter of thestrut barrel or boss to the outside of the shell plating,is not to exceed 10.6 times the diameter of the tailshaft. Where this length is exceeded, the width andthickness of the strut are to be increased, and the strutdesign will be given special consideration. Wherestrut length is less than 10.6 x required tailshaftdiameter, the section modulus of the strut may bereduced in proportion to the reduced length, providedthe section modulus is not less than 0.85 x Guiderequired section modulus.

PART 3 SECTION 5|1 Rudders

PART 3 SECTION 5

Rudders

3/5.1 General

3/5.1.1 ApplicationThis section applies to flat plate and foil profile spaderudders. Rudders having other profiles or withspecial arrangements for increasing rudder force, suchas fins, flaps, steering propellers or other means ofsteering will be subject to special consideration.Where rudders are fitted on horns or shoepieces, theyare to comply with 3/5 of the Rules for Building andClassing Steel Vessels. The surfaces of rudder stocksin way of exposed bearings are to be of non-corrosivematerials. Special consideration will be given toaluminum rudder stocks and fiber reinforced plasticrudders and rudder stocks. Material specifications areto be listed on the plans.

3/5.1.2 Rudder and Rudder Stock MaterialsRudders, rudder stocks, coupling bolts, and keys areto be made from material in accordance with therequirements of Section 2/1. Material tests forcoupling bolts and torque transmitting keys need notbe witnessed by the Surveyor. The surfaces of rudderstocks in way of exposed bearings are to be ofnoncorrosive material.

Material factors for castings and forgings used forthe stock (Ks), bolts (Kb), and coupling flange (Kf),are to be obtained from the following equation.

K = (ny/Y)e

ny = 235 N/mm2 (24 kgf/mm2, 34000 psi)Y = Specified minimum yield strength of the

material in N/mm2 (kgf/mm2, psi) but is notto be taken as greater than 0.7U or 450N/mm2 (46 kgf/mm2, 65000 psi) whicheveris lesser.

U = minimum tensile strength of material used inN/mm2 (kgf/mm2, psi)

e = 1.0 for Y ≤ 235 N/mm2 (24 kgf/mm2, 34000psi)

= 0.75 for Y > 235 N/mm2 (24 kgf/mm2, 34000psi)

3/5.1.3 Expected TorqueThe torque considered necessary to operate therudder in accordance with 4/8.8.2 is to be indicatedon the submitted rudder or steering gear plan. See4/8.1.3 and 3/5.2.2c.

3/5.2 Design Loads

3/5.2.1 Rudder ForceWhere the rudder profile can be defined by a

single quadrilateral, the rudder force is to be obtainedfrom the following equation. Where the rudder angleφ, exceeds 35°, the rudder force, CR, is to beincreased by a factor of 1.74 sin (φ).

CR = nCSKTAV2 kN (tf, Ltf)

CR = rudder force.A = total projected area of rudder in m2 (ft2)KT = 1.463 ahead, 1.682 ahead behind fixed

propeller nozzle.= 1.063 astern (1.2 for flat sided rudders

astern), 1.22 astern behind fixed propellernozzle (1.38 for flat sided rudders asternbehind fixed propeller nozzle).

CS = Speed coefficient.= 1.0 for Vd < 20 knots;

= 159 0 0466

3

. .−

V

∆ where Vd ≥ 20 knots,

but need not exceed 1.0 and is not to betaken less than 0.45.

V = Vd for the ahead condition but is not to betaken as less than Vmin.

= Va for the astern condition but is not to betaken as less than 0.5Vd or 0.5Vmin,whichever is greater.

Vd = the maximum speed in knots with the craftrunning ahead at the maximum continuousrated shaft rpm and at the summer loadwaterline.

Va = maximum astern speed in knots.Vmin = ( ) 320+dV∆ = maximum craft displacement in metric tons

(long tons)n = 0.132 (0.0135, 0.0132)


FIGURE 3/5.1Rudder

3/5.2.2 Rudder Torque for Scantlingsa General The torque to be used for the rudder

scantlings is to be as defined in 3/5.2.2b below.b Rudder Blades The rudder torque for both the

ahead and astern conditions is to be determined fromthe following equation.

QR = CRr kN-m (tf-m, Ltf-ft)

QR = rudder torque.CR = rudder force as calculated in 3/5.2.1r = c(α-Af/A) (but not less than 0.1c for ahead

condition)c = mean breadth of rudder area in m (ft) from

Fig. 3/5.1α = 0.33 ahead, 0.66 astern.Af = Area of rudder blade situated forward of the

centerline of the rudder stock in m2 (ft2).A is as defined in 3/5.2.1.

c Trial Conditions The above values of QR areintended for the design of rudders and should not bedirectly compared with the torques expected duringthe trial (see 3/5.1.3) or the rated torque of steeringgear (see 4/8.1.3).

3/5.3 Rudder Stocks

3/5.3.1 Upper Rudder StocksThe upper rudder stock is that part of the rudder stockabove the neck bearing or above the top pintle. At theupper bearing or tiller, the upper stock diameter is notto be less than obtained from the following equation:

S N Q Ku R s= 3 mm (in)

S = Upper stock required diameter.Nu = 42.0 (89.9, 2.39)

QR = Total rudder torque as defined in 3/5.2.2 inkN-m (tf-m, Ltf-m)

Ks = Material factor for upper rudder stock asdefined in 3/5.1.2

3/5.3.2 Lower Rudder StocksThe lower rudder stock diameter is to be determinedusing the given rudder force and torque in 3/5.2.Bending moments, shear forces and reaction forcesare to be determined from 3/5.3.3, and 3/5.7.3.

The lower rudder stock diameter is not to be lessthan obtained from the following equation.

( )( )S S M Ql R= +1 4 326 mm (in)

S = upper stock required diameter from 3/5.3.1in mm (in.)

Sl = lower stock required diameter.M = bending moment at the station of the rudder

stock considered in kN-m (tf-m, Ltf-ft)QR = rudder torque from 3/5.2.2 in kN-m (tf-m,

Ltf-ft)

Where the diameter at the neck bearing differs fromthe diameter of the upper bearing or tiller, a gradualtransition is to be provided between the differentdiameter stocks.

3/5.3.3 Bending MomentsThe bending moment on the rudder and rudder stockmay be determined in accordance with Appendix 3/Aor in accordance with the following equations.

M Cn R n= ! kN-m (Ltf-ft)

M CA

As R c= 1 ! kN-m (Ltf-ft)

Mn = bending moment at neck bearing.Ms = bending moment at section under

consideration.! n = distance from center of neck bearing to the

centroid of rudder area, m (ft)! c = distance from section under consideration to

the centroid of rudder area, A1, m (ft)A1 = area below section under consideration, m2

(ft2)CR and A are as defined in 3/5.2.1

3/5.5 Rudder Couplings

3/5.5.1 Flange CouplingsRudder couplings are to be supported by an amplebody of metal worked out from the rudder stock. Thematerial outside the bolt holes is not to be less thantwo thirds the diameter of the bolt. Suitable means of


locking the nuts are to be provided. The diameter ofthe bolts and the flange thicknesses are not to be lessthan obtained from the following equations.

a Horizontal Couplings There are to be at leastsix coupling bolts in horizontal couplings, and thediameter of each bolt is not to be less than obtainedby the following equation.

( )d d K nrKb s b s= 0 62 3. mm (in)

db = bolt diameter.n = total number of bolts in coupling.r = mean distance in mm (in) of the bolt centers

from the center of the system of bolts.ds = required diameter of stock in way of

coupling, S or Sl from 3/5.3.1 or 3/5.3.2 asthe case may be in mm (in)

Kb = material factor for bolts as defined in 3/5.1.2Ks = material factor for stock as defined in 3/5.1.2

Coupling flange thickness is not to be less than thelesser of the following equations.

t d K Kf b f b= mm (in) t df b= 0 9. mm (in)

Kf = material factor for flange as defined in3/5.1.2

db = required bolt diameter calculated for anumber of bolts not exceeding 8.

b Vertical Couplings There are to be at least eightcoupling bolts in vertical couplings and the diameterof each bolt is not to be less than obtained from thefollowing equation.

( )d d K nKb s b s= 0 81. mm (in)

n = total number of bolts.ds, Kb, Ks as defined above.

In addition, the first moment of area of the boltsabout the center of the coupling is not to be less thangiven by the following equation.

m = 0.00043ds3 mm3 (in3)

m = first moment of area.ds = diameter as defined in 3/5.5.1a

Coupling flange thickness is not to be less than db.

3/5.5.2 Tapered Stock Couplingsa Taper Ratio Tapered stocks secured to the

rudder casting by a nut on the end of the stock are tohave a length of taper in the casting generally not lessthan 1.5 times the diameter of the stock at the top ofthe rudder. Couplings without hydraulic arrangementsfor mounting and dismounting the coupling are tohave a taper on diameter of 1/8 to 1/12. For couplings

with hydraulic arrangements for mounting anddismounting the coupling (mounting with oil injectionand hydraulic nut) the taper on the diameter is to be1/12 to 1/20, and the push-up oil pressure and thepush up length will be specially considered uponsubmission of calculations in each case.

b Keying Where the stock is keyed to the ruddercasting, torsional strength equivalent to that of therequired upper stock diameter is to be provided. Thetop of the keyway is to be located well below the topof the rudder. For higher strength materials, shear andbearing areas of keys and keyways are to be based onthe lesser strength properties of the key and thematerials in which keyways are cut, as appropriate.

c Locking Nut The nut is to be proportioned inaccordance with the following and is to be fitted withan effective locking device. (See Figure 3/5.2).

external thread diameter dg ≥ 0.65 do

length of nut hn ≥ 0.6 dg

outer diameter of nut dn ≥ 1.2du or 1.5dg

whichever is greater

FIGURE 3/5.2Tapered Couplings

3/5.5.3 Keyless CouplingsHydraulic and shrink fit keyless couplings will bespecially considered upon submittal of detailedpreloading and stress calculations and fittinginstructions. The calculated torsional holding capacityis to be at least 2.0 times the transmitted torque basedon the steering gear relief valve setting. Preload stressis not to exceed 70% of the minimum yield strengthof the rudder stock housing or the rudder stockmaterials.


3/5.9 Double Plate Rudder

3/5.9.1 StrengthThe section modulus and web area of the ruddermainpiece are to be such that the following stressesare not exceeded.

In calculating the section modulus of the rudder,the effective width of side plating is to be taken as notgreater than twice the athwartship dimension of therudder. Generous radii are to be provided at abruptchanges in section, and in way of openings, includingthose with cover plates.

Moments and reaction forces are to be as given in3/5.3.3.

bending stress σb 110 N/mm2

(11.2 kgf/mm2,16000 psi)

shear stress τ 50 N/mm2

(5.1 kgf/mm2,7300 psi)

equivalentstress σ σ τe

2 2b 3= + 120 N/mm2

(12.2 kgf/mm2,17000 psi)

The mainpiece of the rudder is to be formed bythe rudder side plating (but not more than theeffective width indicated above) and verticaldiaphragms extending the length of the rudder or theextension of the rudder stock or a combination ofboth.

The section modulus at the bottom of the rudder isnot to be less than one-third the required sectionmodulus of the rudder at the top of the rudder or atthe center of the lowest pintle.

3/5.9.2 Rudder platinga Side, Top and Bottom Plating The plating

thickness is not to be less than obtained from thefollowing equation.

( )t s k d k C A Q kR= + × +.0055 1 2 3β mm (in)

k1 = 1.0 (1.0, 0.305)k2 = 0.1 (0.981, 10.7)k3 = 2.5 (2.5, 0.1)d = Summer loadline draft of the ship in m (ft)CR = Rudder force according to 3/5.2 in kN (tf,

Ltf)A = Rudder area in m2 (ft2)s = smaller unsupported dimension of plating in

mm (in)b = greater unsupported dimension of plating in

mm (in)

β = ( )11 0 5 2. .− s b ; maximum 1.0 for b/s ≥ 2.5

Q = material factor for rudder plating as definedin 3/6.1.1a

The thickness of the rudder side or bottom plating isto be at least 2 mm (0.08 in.) greater than thatrequired by 3/9.1.2a for deep tank plating inassociation with a head h measured to the summerload line.

b Diaphragm Plates Vertical and horizontaldiaphragms are to be fitted within the rudder,effectively attached to each other and to the sideplating. Vertical diaphragms are to be spacedapproximately 1.5 times the spacing of horizontaldiaphragms. Openings are in general not to be morethan 0.5 times the depth of the web.

The thickness of diaphragm plates is not to be lessthan 70% of the required rudder side plate thicknessor 8 mm (0.31 in.) whichever is greater. Welding is tobe in accordance with Section 2/3A and 3/23. Whereinaccessible for welding inside the rudder, it isrecommended that diaphragms be fitted with flat barsand the side plating be connected to these flat bars bycontinuous welds or by 75 mm (3 in.) slot weldsspaced at 150 mm (6 in.) centers. The slots are to befillet welded around the edge, and filled with asuitable compound.

c Watertightness The rudder is to be watertightand is to be tested in accordance with Table 1/2.1.

3/5.10 Single Plate Rudders

3/5.10.1 Mainpiece DiameterThe mainpiece diameter is calculated according to3/5.3.2. The lower third may be tapered down to 0.75times stock diameter at the bottom of the rudder.

3/5.10.2 Blade ThicknessThe blade thickness is not to be less than obtainedfrom the following equation.

tb = 0.0015sV + 2.5 mm

tb = 0.0015sV + 0.1 in

s = spacing of stiffening arms in mm (in), not toexceed 1000 mm (39 in.)

V = speed as defined in 3/5.2.13/5.10.3 ArmsThe thickness of the arms is not to be less than theblade thickness obtained in 3/5.10.2. The sectionmodulus of each set of arms about the axis of therudder stock is not to be less than obtained from thefollowing equation.

SM = .0005 sCl2V2 cm3

SM = .0000719 sCl2V2 in3

Cl = horizontal distance from the aft edge of therudder to the centerline of the rudder stockin m (ft)

s, V are as defined in section 3/5.10.2.


3/5.11 Rudder Stops

Strong and effective rudder stops are to be fitted.Where adequate positive stops are provided withinthe gear, structural stops will not be required. Seealso 4/8.

3/5.13 Supporting and Anti-Lifting Arrangements

3/5.13.1 Rudder Stock Bearingsa Bearing Surfaces The bearing surface Ab for

rudder stocks, shafts and pintles is not to be less thanobtained from the following equation.

Ab = 1000 P/qa mm2 Ab = 2240 P/qa in2

Ab = projected area of bearing surface = dllb

where dl is the outer diameter of the linerand lb is the bearing length not to be takengreater than 1.2d.

P = Bearing reaction force in kN (tf, Ltf) .SeeAppendix 3/A.1.4.

qa = allowable surface pressure asindicated in Table 3/5.2 depending on bearingmaterial in N/mm2 (kgf/mm2, psi)

b Bearing Clearance With metal bearingsclearance is not to be less than db/1000 + 1.0 mm,(db/1000 + .04 in) on the diameter. If non-metallicbearing material is applied, the bearing clearance is tobe specially determined considering the material'sswelling and thermal expansion properties. Thisclearance is in no case to be taken less than 1.5 mm(0.06 in) on the diameter or the bushing

manufacturer’s recommended running clearance. Forspade rudders with a rudder stock diameter of 400mm(15.75 in.) or less, the clearances on the diameter arenot to be less than given below:

StockDiameter,mm (in.)

MetallicBushing,mm (in.)

SyntheticBushing 1,mm (in.)

400 (15.75) 1.15 (0.045) 1.15 (0.045) + E2

300 (11.81) 0.85 (0.033) 0.85 (0.033) + E200 (7.87) 0.78 (0.031) 0.78 (0.031) + E100 (3.94) 0.75 (0.030) 0.75 (0.030) + E

Notes:1. The bushing manufacturer’s recommended

running clearance may be used as an alternativeto these clearances.

2. E = expansion allowance provided by bushingmanufacturer, mm (in.).

3/5.13.2 Rudder Carrier and Anti Lifting DevicesEffective means are to be provided for supporting theweight of the rudder assembly. At least half of therudder carrier holding-down bolts are to be fittedbolts. Alternatively, other effective means ofpreventing horizontal movement of the rudder may bespecially considered. Means are also to be providedto prevent accidental unshipping, lifting or unduemovement of the rudder which may cause damage tothe steering gear. See Appendix 3A for guidance.

TABLE 3/5.2Bearing Pressure

qaƒ

Bearing Material N/mm2 kgf/mm2 psi

lignum vitae 2.5 0.25 360

white metal, oil lubricated 4.5 0.46 650

synthetic material with hardness between 60 and 70 Shore D* 5.5 0.56 800

steel§, bronze and hot-pressed bronze-graphite materials 7.0 0.71 1000

ƒ Higher values than given in the table may be taken if they are verified by tests.§ Stainless and wear-resistant steel in an approved combination with stock liner.* Indentation hardness test at 23°C and with 50% moisture, according to a recognized standard. Synthetic

bearing materials to be of approved type.

PART 3 SECTION 6|1 Primary Hull Strength

PART 3 SECTION 6

Primary Hull Strength

3/6.1 Longitudinal Hull Girder Strength- Monohulls

The equations are, in general, valid for craft havingbreadths, B, not greater than twice their depths, D, asdefined in 3/1.

3/6.1.1 Section Modulusa All craft The required hull girder section

modulus SM at amidships is to be not less than givenby the following equation:

SM = C1C2L2B(Cb+0.7)K3K4CQ cm2m (in.2ft)

where:

C1 = 30.67 – 0.98L 12 ≤ L < 18 m= 22.40 – 0.52L 18 ≤ L < 24 m= 15.20 – 0.22L 24 ≤ L < 35 m= 11.35 – 0.11L 35 ≤ L < 45 m= 6.40 45 ≤ L < 61 m= 0.0451L + 3.65 L ≥ 61 m

C1 = 30.67 – 0.299L 40 ≤ L < 59 ft= 22.40 – 0.158L 59 ≤ L < 79 ft= 15.20 – 0.067L 79 ≤ L < 115 ft= 11.35 – 0.033L 115 ≤ L < 150 ft= 6.40 150 ≤ L < 200 ft= 0.0137L + 3.65 L ≥ 200 ft

C2 = 0.01 (0.01, 1.44 x 10-4)L = length of craft in m or ft as defined in Section

3/1B = breadth in m of ft as defined in Section 3/1V = maximum speed for the specified sea state, in

knotsCb = block coefficient at design draft, based on the

length, L, measured on the design loadwaterline. Cb is not to be taken as less than0.45 for L < 35m (115 ft) or 0.6 for L ≥ 61m(200 ft). Cb for lengths between 35m (115 ft)and 61m (200ft) is to be determined byinterpolation.

K3 = (0.70 + 0.30

V

L+

1 20

3 64

.

.) SI/MKS units,

(0.70 + 0.30 V

L+

0 66

2 01

.

.

) US Units;

K3 is not to be taken less than 1.K4 = 1.0 for craft in Unrestricted Ocean Service.

= 0.9 for craft in restricted serviceC = 1.0 for steel craft, 0.90 for aluminum craft

and 0.80 for fiber-reinforced plastic craftQ for steel

= 1.0 for ordinary strength steel= 0.78 for grade H32 steel= 0.72 for grade H36 steel

Q for aluminum= 0.9 + q5 but not less than Qo

q5 = 115/σy , (12/σy , 17000/σy )Qo = 635/(σy +σu), (65/(σy + σu), 92000/(σy +σu ))σy = minimum yield strength of welded aluminum

in N/mm2 (kgf/mm2, psi)σu = minimum ultimate strength of welded

aluminum in N/mm2 (kgf/mm2, psi)Q for fiber reinforced plastic

= 400/σu, (41/σu, 58000/σu )σu = minimum ultimate tensile or compressive

strength whichever is less, verified byapproved test results, in N/mm2 (kgf/mm2,psi). See 2/5.5. Strength properties in thelongitudinal direction of the craft are to beused.

b Craft 61 m (200 ft.) in Length and Over Inaddition to meeting the above criteria in 3/6.3.1a, craftof 61 m (200 ft.) in length or greater are to complywith the following requirements.

1 Sign Convention of Bending Moment andShear Force The sign convention of bending momentand shear force is as shown in Figure 3/6.1.

FIGURE 3/6.1Sign Convention


2 Wave Bending Moment Amidships The wavebending moment, expressed in kN-m (tf-m, Ltf-ft), maybe obtained from the following equations.

Mws = -k1C1L2B(Cb + 0.7) x 10-3 Sagging Moment

Mwh = +k2C1L2BCb x 10-3 Hogging Moment

k1 = 110 (11.22, 1.026)k2 = 190 (19.37, 1.772)

C1, L, B, and Cb are as defined in 3/6.1.1a3 Section Modulus The required hull-girder

section modulus for 0.4L amidships is to be obtainedfrom the following equation.

SMM K CQ

ft

p

= 3 cm2m (in2ft)

K3, C, and Q are as defined in 3/6.1.1aIn the case of restricted ocean service, considerationmay be given to a seakeeping analysis based on craftspeed and sea state to determine Mws and Mwh. In suchcases K3 and Fs are to be taken as 1.0

Mt = Msw+MwFs

Msw = maximum still-water bending moment in thehogging condition and the sagging conditionin kN-m (tf-m, Ltf-ft), generally Msw is not tobe taken less than 0.5 Mws.

Mw = maximum wave induced bending moment inkN-m (tf-m, Ltf-ft) as determined in3/6.1.1(b)(2)

fp = 17.5 kN/cm2, (1.784 tf/cm2, 11.33ltf/in2)Fs = restriction factor based on significant wave

height as shown in Table 3/6.1

Table 3/6.1 Service Factor, Fs

Area ofOperation

Significant Wave Height m (ft) Fs

UnrestrictedService

h1/3 ≥ 4.0 (13.0) 1.00

RestrictedService

3.5 ≤ h1/3 ≤ 4.0 (11.5 ≤ h1/3 ≤ 13.0) 0.80

2.0 ≤ h1/3 ≤ 3.5 (8.5 ≤ h1/3 ≤ 11.5) 0.700.5 ≤ h1/3 ≤ 2.5 (1.5 ≤ h1/3 ≤ 8.5) 0.50

c Planing and Semi-planing Craft Where the craftspeed exceeds 25 knots, the hull-girder sectionmodulus is also to be not less than obtained by thefollowing equations, whichever is greater:

( )SML

CY Y C Qw

F cg= − −∆

2

128 178 50 cm2m

(in2ft)

or

( )S ML

CY Y C Qw

cg A= − −∆

2

7 8 1 2 8 5 0 cm2m

(in2ft)

where:

∆ = maximum craft displacement in metric tons(long tons)

Lw = length of craft on design waterline in m (ft.)YF = vertical acceleration at forward end, generally

taken as 1.2ncg, however where L is greaterthan 61 meters, or where Vk is greater than 35knots, it is to be determined by model testsand submitted for review.

ncg = as defined in 3/8.1.1C2 = 1320 SI and MKS units or 8380 US unitsYcg = vertical acceleration at longitudinal center of

gravity, average 1/10 highest accelerations, ing’s. Where Ycg is not submitted by thedesigner, it is to be taken as not less than0.6ncg, where ncg is as given in 3/8.1.1a.However, where L is greater than 61 m (200ft), or where Vk is greater than 35 knots, thevertical acceleration is to be determined bymodel tests and submitted for review.

YA = vertical acceleration at aft end. In general,this is to be taken as 0, however where L isgreater than 61 meters, or where Vk is greaterthan 35 knots, it is to be determined by modeltests and submitted for review.

C = coefficient given in 3/6.1.1aQ = material coefficient given in 3/6.1.1aWhere displacement and speed vary with loadingcondition, calculation above is to be performed for allpossible combinations of displacement and speed.

3/6.1.2 Extension of Midship Section ModulusWhere the still-water bending moment envelope is notsubmitted or where 3/6.1.1a or 3/6.1.1c govern, thescantlings of all continuous, or effectively developed,longitudinal material is to be maintained within the0.4L amidships and gradually tapered beyond.

Where the scantlings are based on the envelopecurve of still-water bending moments, items includedin the hull-girder section modulus amidships are to beextended as necessary to meet the hull-girder sectionmodulus required at the location being considered.

The envelope curve of Mws and Mwh may beobtained by multiplying the midship value by thedistribution factor M in Figure 3/6.2.


FIGURE 3/6.2Distribution Factor M

3/6.1.3 Moment of InertiaThe hull-girder moment of inertia, I, at amidships is tobe not less than given by the following equation:

K

SM

Q

LI = cm2m2 (in2ft2)

where:I = required hull girder inertia, in cm2m2 (in2ft2)SM = required hull girder section modulus in

3/6.1.1,a b or c, whichever is greatest, incm2m (in2ft)

K = factor dependent on material and service asgiven in Table 3/6.2

L and Q are as defined in 3/6.1.1.a.

Table 3/6.2 Factor, KSteel Aluminum FRP

(ABS BasicLaminate)1

Restricted ServiceL < 90 m

40 13.33 1.8

Unrestricted ServiceL < 90 m

50 13.33 1.8

Unrestricted ServiceL > 90 m

33.3 11.1 1.5

Note: For fiber reinforced plastic laminates that are greater thanthe ABS basic laminate (as defined in Part 2, Section 5) thevalue of K can be adjusted by the ratio of Eo/Eb whereEo = the elastic modulus of the actual hull laminate,

in N/mm2 (kgf/mm2, psi)Eb = 6890 N/mm2 (703 kgf/mm2, 1 × 106 psi)

3/6.1.4 Section Modulus and Moment of InertiaCalculation

a Items Included in the Calculation In general,the following items may be included in the calculationof the section modulus and moment of inertia providedthey are continuous or effectively developed withinmidship 0.4L, have adequate buckling strength, andare gradually tapered beyond the midship 0.4L.

Deck plating (strength deck and other effectivedecks)Shell and inner bottom platingDeck and bottom girdersPlating and longitudinal stiffeners of longitudinalbulkheads

All longitudinals of deck, sides, bottom, andinner bottom

b Effective Areas Included in the Calculation Ingeneral, the net sectional areas of longitudinal strengthmembers are to be used in the hull girder sectionmodulus calculations, except that small isolatedopenings need not be deducted provided the openingsand the shadow area breadths of other openings in anyone transverse section do not reduce the sectionmodulus by more than 3%. The breadth or depth ofsuch openings is not to be greater than 25% of thebreadth or depth of the member in which it is locatedwith a maximum of 75 mm (3 in.) for scallops. Theshadow area of an opening is the area forward and aftof the opening enclosed by the lines tangential to thecorners of the opening intersecting each other to forman included angle of 30 degrees.

c Section Modulus to the Deck or Bottom Thesection modulus to the deck or bottom is obtained bydividing the moment of inertia by the distance fromthe neutral axis to the molded deck at side amidshipsor baseline, respectively. Where a long deckhouse orsuperstructure is considered as part of the hull girder,the section modulus to the deck is obtained bydividing the moment of inertia by the distance fromthe neutral axis to the top of the bulwark, deckhouse orsuperstructure.

3/6.1.5 Hull Girder Shear Strength Calculation- For Craft 61m (200 ft.) in Length andOver

a General The nominal total shear stresses due tostill-water and wave-induced loads are to be based onthe maximum algebraic sum of the shear force in still-water, Fsw , and the wave indicated shear force, Fw , atthe location being considered. The thickness of theside shell is to be such that the nominal total shearstress as obtained by 3/6.1.5c are not greater than11.0/Q kN/cm2 (1.122/Q tf/cm2, 7.122/Q Ltf/in.2)where Q is as defined in 3/6.1.1a. Consideration isalso to be given to the shear buckling strength of theside shell plating.

b Wave Shear Forces The envelopes ofmaximum shearing forces induced by waves Fw asshown in Figures 3/6.3 and 3/6.4 may be obtainedfrom the following equations.

Fwp = +kF1C1LB(Cb + 0.7) x 10-2 For positive shear force

Fwn = -kF2C1LB(Cb + 0.7) x 10-2 For negative shearforce

Fwp, Fwn = maximum shearing force induced by wavein kN (tf, Ltf)

k = 30 (3.059, 0.2797)F1 = distribution factor as shown in Figure 3/6.3F2 = distribution factor as shown in Figure 3/6.4C1, L, B, and Cb are as defined in 3/6.1.1a


FIGURE 3/6.3Distribution Factor F1

FIGURE 3/6.4Distribution Factor F2

c Shear Strength For craft without continuouslongitudinal bulkheads, the nominal total shear stress fs

in the side shell plating may be obtained from thefollowing equation.

fs = (Fsw + FsFw)m/2tsI

fs = nominal total shear stress in kN/cm2 (tf/cm2,Ltf/in.2)

I = moment of inertia of the hull girder section incm4 (in.4) at the section under consideration

m = first moment in cm3 (in.3), about the neutralaxis, of the area of the effective longitudinalmaterial between the horizontal level atwhich the shear stress is being determinedand the vertical extremity of effectivelongitudinal material, taken at the sectionunder consideration.

ts = thickness of the side shell plating in cm (in.)at the position under consideration.

Fsw = hull-girder shearing force in still-water in kN(tf, Ltf)

Fw = Fwp or Fwn as specified by 3/6.1.4b,depending upon loading.

Fs is as defined in 3/6.1.1b

d Hull-girder Shear Strength - FRP Craft Hull-girder shear strength will be specially considered onfiber reinforced plastic craft over 61m (200ft.) inlength.

e Craft of unusual proportion Craft havingunusual proportions will be specially considered.

3/6.1.6 Hull Girder Torsional LoadsTorsional calculations may be required for craft withlarge deck openings. Racking load calculations maybe required for craft with tall superstructures.

3/6.3 Primary Hull Strength - Twin-HulledCraft

3/6.3.1 Longitudinal Hull Girder StrengthThe longitudinal strength requirements for twin-hulledcraft are as given in 3/6.1. With the followingmodifications

i B is to be taken as the sum of the waterlinebreadths of each hull.

ii For craft less than 61m (200ft) longitudinalshear strength need not be considered unless they haveunusual or highly concentrated loads. For craft over61m (200ft) the shear strength will be speciallyconsidered.

iii Items as listed in 3/6.1.3 may be included inthe longitudinal strength calculation for the total crosssection of the hulls, with the addition of the cross deckbridging structure.

3/6.3.3 Transverse and Torsional BendingMoments and Shear Force

The transverse primary bending moments and shearforce for the hull bridging structure (i.e. crossstructure) are obtained from the following equations:

Mtb = K1∆Bcln kN-m (kgf-m, ft-lbs)

Mtt = K2∆Ln kN-m (kgf-m, ft-lbs)

Qt = K1∆n kN (kgf, lbs)

Mtb = design transverse bending moment actingupon the cross structure connecting the hulls.

Mtt = design torsional moment acting upon thecross structure connecting the hulls.

Qt = design vertical shear force acting upon thecross structure connecting the hulls.

K1 = 2.5 (0.255, 0.255)K2 = 1.25 (0.1275, 0.1275)∆ = craft displacement in tonnes (kg, lbs).Bcl = distance in meters or feet between the hull

centerlines.L = length of craft in meters or feet as defined in

3/1.1.n = vertical acceleration at the craft’s center of

gravity, see 3/8.1.1


3/6.3.4 Catamaran and SES Transverse andTorsional Section Modulus and ShearArea

The required transverse section modulus and sheararea for catamarans and surface effect craft areobtained from the following equations:

SMtb = Mtb/σa cm2m (in2ft)

SMtt = Mtt/σab cm2m (in2ft)

Ast = Qt/τa cm2 (in2)

SMtb= required section modulus of the crossstructure

SMtt= required torsional section modulus of thecross structure

Ast = required shear area of the cross structureMtb = design transverse bending moment acting

upon the cross structure connecting the hulls.Mtt = design torsional moment acting upon the

cross structure connecting the hulls.Qt = design vertical shear force acting upon the

cross structure connecting the hulls.σa = 0.66σy, tensile or compressive stress.τa = 0.38σy, shear stress.σab = 0.75σy, combined or von Mises stress.σy = minimum yield stress of the material, for

aluminum the yield stress is to be for theunwelded condition.

3/6.3.5 Items included in Transverse Moment ofInertia and Section Modulus Calculation

The following items may be included in the calculationof the transverse section modulus and moment ofinertia provided that are continuous or effectivelydeveloped over the entire breadth of the cross structureor wet deck, and have adequate buckling strength:

Deck plating, main deck and bottom shell of wet deckTransverse stiffeners on wet deckTransverse bulkheads or web frames which span the

wet deckTransverse girders or box beamsContinuous transom plating and horizontal stiffeners

attached

In general, the effective sectional area of the deckfor use in calculating the section modulus is to excludehatchways and other large openings in the deck.

Superstructures and house tops are generally not tobe included in the calculation of sectional properties ofthe cross structure. Craft having unusual configurationor large bracketed overhead “bent” type structures willbe specially considered

See appendix 3/B for guidance on calculating theoffered torsion strength of the craft.

3/6.3.6 Craft With More Than Two HullsTransverse and Torsional Strength of craft with morethan two hulls will be specially considered.

3/6.4 Strength Considerations for HydrofoilBorne Craft

3/6.4.1 Longitudinal StrengthThe craft’s weight curve showing full load, light ship,and partial load if more severe is to be submitted. Thesupport reactions for each of the hydrofoils are to beshown. The resulting shear and bending momentdiagrams, as derived from these curves, are to besubmitted for approval.

Hull deflection under the condition of maximumbending moment is not to exceed 1/200 of the distancebetween the forward and aft foil attachment points.

3/6.4.2 Calculation of Loads from HydrofoilAppendages

The maximum forces transmitted by any hydrofoil tothe craft structure is given by the following equations:

FL = CUCLV2AP

FD = CUV2(CDFAFF + CDSAFS) + (Wetted surface drag)

FL = maximum lift force on craft exerted byhydrofoil in kgf (lbs). This force is assumedto act perpendicular to the plane of the foil.

FD = maximum drag force on craft exerted byhydrofoil plus strut in kgf (lbs). This force isassumed to act directly aft from the center ofthe foil.

CU = 13.847 (2.835)CL = peak coefficient of lift for the foil selected.CDF = peak coefficient of drag for the foil selected.CDS = peak coefficient of drag for the strut section

selected.V = maximum craft speed in knots.AP = plan view area of foil in m2 or ft2

AFF = frontal area of foil in m2 or ft2

AFS = frontal area of strut in m2 or ft2

Total drag of foil and the strut (or similar appendage)is the drag term as shown above, plus the frictionaldrag of skin friction coefficient, as a function ofwetted surface and Reynolds number.

The bending moment of the foil and appendagethat acts on its attachment to the hull is to becalculated and compared to the strength of theconnection. A safety factor of 2.0 against themaximum combined lift and drag loads is theminimum acceptance criteria. Calculations forbending moment, stiffness, and shear are to be carriedout and submitted by the designer.


Additionally, calculations supporting the “Fail-Safe” performance of each foil attachment structureare to be submitted.

Watertight integrity of the shell is to be maintainedin the event of a collision of hydrofoil appendageswith a solid object underwater. A design safety factorof 3.0 against the yield strength or 2.0 against theultimate strength of the foil strut bearing are to be usedto assess the strength of the foil for the collisioncondition.3/6.5 Effective DecksTo be considered effective for use in calculating thehull girder section modulus, the thickness of the deckplating is to comply with the requirements of Section3/9. The deck areas are to be maintained throughoutthe midship 0.4L and may be gradually reduced to onehalf their midship value at 0.15L from the ends. Onlythat portion of deck which is continuous through thetransverse structure may be considered effective.

3/6.9 Operating ManualCraft are to be furnished with an operating manualproviding guidance on;

a loading conditions on which the design of thecraft has been based, including cargo loading ondecks, loading ramps, and double bottoms.

b permissible limits of still-water bendingmoments and shear forces, for craft 61m (200 ft.) inlength or greater.

c maximum operational speeds for the various sea-states (significant wave heights) in which the craft isintended to operate.

d other operational limits as applicable such asdistance from place of refuge.

PART 3 SECTION 8|1 Design Pressures

PART 3 SECTION 8

Design Pressures

3/8.1 Monohulls

3/8.1.1 Bottom Structure Design PressureThe minimum bottom design pressure is to be thegreater of a or b as given in the following equations,for the location under consideration. Bottomstructure design pressures are dependent upon theservice in which the craft operates. The bottompressure herein calculated applies to hull bottomsbelow the chines or the turn of the bilge.

a Bottom Slamming Pressure

Dcgww

bcg FnBL

Np ]1[1 +

∆= kN/m2 (tf/m2, psi)

Dcg

xxxx

wwbxx Fn

BL

Np

−−

+∆

=ββ

70

70]1[1 kN/m2

(tf/m2, psi)

for craft less than 61m (200ft), pbxx may be taken as:

vDcgww

bxx FFnBL

Np ]1[1 +


b Hydrostatic Pressure

p N F H dd s= +3 ( ) kN/m2 (tf/m2, psi)

pbcg = bottom design pressure at LCG, kN/m2

(tf/m2, psi)pbxx = bottom design pressure at any section clear

of LCG, kN/m2 (tf/m2, psi)pd = bottom design pressure based on hydrostatic

forces, kN/m2 (tf/m2, psi)ncg = average of the 1/100 highest vertical

accelerations at LCG, corresponding to thesea state, in g’s. g’s are the dimensionlessratio of the acceleration to gravitationalacceleration at sea level (9.8 m/s2, 32.2ft/s2). Can be determined by the followingequation:

∆−

+=

223/1

2)(

]50[0.112 w

cgw

cgBV

B

hNn βτ g’s

nxx = average of the 1/100 highest verticalaccelerations, at any section clear of LCG, ing’s. Can be determined by the followingequation:

nxx = ncgKv

N1 = 0.1 (.01, .069)N2 = 0.0078 (0.0078, 0.0016)N3 = 9.8 (1.0, 0.44)∆ = displacement at design waterline in kg or lbsLw = craft length on the waterline with the vessel

at the design displacement and in thedisplacement mode, in m or ft

Bw = maximum waterline beam, in m or ftH = wave parameter, 0.0172L + 3.653m

(0.0172L + 11.98ft)h1/3 = significant wave height, m (ft) for the sea

state being considered, generally not to betaken as less than Lw/12 except for restrictedservice operation as given in Table 3/8.1.

τ = running trim at V, in degrees, but generallynot to be taken less than 4° for craft L<50m(165 ft), nor less than 3° for L <125m(410ft). Special consideration will be givento designers values predicted from modeltests.

βcg = deadrise at LCG, degrees, generally not tobe taken less than 10° nor more than 30°.

βxx = deadrise at any section clear of LCG, indegrees, not to be taken less than 10° orgreater than 50°

V = craft design speed in knots, generallymaximum speed in calm water; consideringservice needs to limit vertical accelerations,design service speeds may vary withsignificant wave height provided guidance isgiven in Operating Manual.

FD = design area factor given in Figure 3/8.1 forgiven values of AD and AR. Generally not tobe taken less than 0.40.

KV = vertical acceleration distribution factor givenin Figure 3/8.2.

FV = vertical acceleration distribution factor givenin Figure 3/8.3.

AD = design area, cm2 (in2). For plating it is theactual area of the shell plate panel but not tobe taken as more than 2s2. For longitudinals,stiffeners, transverses and girders it is theshell area supported by the longitudinal


stiffener, transverse or girder; for transversesand girders the area used need not be takenless than 0.33l2.

AR = reference area, cm2 (in2), 6.95∆/d cm2

(1.61∆/d in2)s = spacing of longitudinals or stiffeners, in cm

or in.l = length of unsupported span of internals. See

3/10.1.2a.d = stationary draft, in m or ft, vertical distance

from outer surface of shell measured atcenterline to design waterline at middle ofdesign waterline length, but generally not tobe taken as less than 0.04L.

Table 3/8.1

Area of Operation Significant Wave Height, m(ft) Fs

Unrestrictedservice

h1/3 ≥ 4.0 (13.0) 1.00

Restricted service 3.5 ≤ h1/3 ≤ 4.0 (11.5 ≤ h1/3 ≤ 13.0) 0.802.5 ≤ h1/3 ≤ 3.5 (8.5 ≤ h1/3 ≤ 11.5) 0.700.5 ≤ h1/3 ≤ 2.5 (1.5 ≤ h1/3 ≤ 8.5) 0.50

3/8.1.2 Side and Transom Structure, DesignPressure

The side design pressure, Ps is to be not less thangiven by the equations:

a Slamming Pressure

Dcg

xxxx

wwsxx Fn

BL

Np

−−

+∆

=ββ

70

70)1(1 kN/m2

(tf/m2, psi)


p N F H d ys s= + −3 ( ) kN/m2 (tf/m2, psi)

c Fore End

p F C N V Lsf s F= + +028 022 015 04 0632. ( . . tan )( . sin . )α β

kN/m2 (tf/m2)

p F C N V Lsf s F= + +092 022 015 04 03332. ( . . tan )( . sin . )α β

psi

N1, N3, ∆, Lw, V, nxx, βcg, H, d, and FD are as definedin 3/8.1.1.

Bw = maximum waterline beam, in m or ftβxx = deadrise at any section clear of LCG,

degrees, not to be taken less than 10° andnot greater than 70°

psxx = side design pressure at any section clear ofLCG, in kN/m2 (tf/m2, psi)

ps = side design pressure due to hydrostaticforces, in kN/m2 (tf/m2, psi), but is not to betaken less than the following:

= 0.05N3L kN/m2 (tf/m2, psi) at or below L/15above the base line or at any height abovebase line forward of 0.125L from the stem.

= 0.033N3L kN/m2 (tf/m2, psi) above L/15above the base line, aft of 0.125L from thestem.

psf = side design pressure for forward of 0.125Lfrom the stem.

y = distance above base line, m or ft, of locationbeing considered.

L = craft length as defined in Section 3/1.1,generally not to be taken less than 30m (98ft.)

Fs = factor as given in table 3/8.1CF = 0.0125L for L < 80m (0.00381L for L < 262

ft)= 1.0 for L ≥ 80m (262 ft)

α = flare angle, the angle between a vertical lineand the tangent to the side shell plating,measured in a vertical plane at 90° to thehorizontal tangent to the side shell.

β = entry angle, the angle between a longitudinalline, parallel to the centerline and thehorizontal tangent to the side shell.

3/8.3 Hydrofoils, Air Cushion Vehicles, SurfaceEffect Craft, and Multi-hull Craft

3/8.3.1 Bottom Structure Design PressureThe minimum bottom design pressure is to be thegreater of a or b as given in the following equations,for the location under consideration. Bottomstructure design pressures are dependent upon theservice in which the craft operates. The bottompressure herein calculated applies to hull bottomsbelow the chines or the turn of the bilge forcatamarans, trimarans or other multihulled craft,surface effect ship, and foil-borne craft. Twin hullbottom of surface effect ships shall be considered ascatamaran hulls for purpose of calculation of thebottom slamming pressure.

a Bottom Slamming Pressure

Dcgwhw

bcg FnBNL

Np ]1[1 +


Dcg

xxxx

whwbxx Fn

BNL

Np

−−

+∆

=ββ

70

70]1[1 kN/m2

(tf/m2, psi)



p N F H dd s= +3 ( ) kN/m2 (tf/m2, psi)

pbcg, pbxx, N1, N2, N3, ∆, Lw, V, ncg, FD, nxx, βxx, βcg, H,d, and FD are as defined in 3/8.1.1.

ncg = average of the 1/100 highest verticalaccelerations at LCG, corresponding to thesea state, in g’s. Can be determined by thefollowing equation:

∆−

+=

223/1

2)(

]50[0.112 h

cghw

cgBNV

NB

hNn βτ

g’s

Bw = maximum waterline beam of one hull in m orft.

Nh = number of hulls

3/8.3.2 Side and Transom Structure, DesignPressureThe side design pressure, Ps is to be not less thangiven by the equations:

a Slamming Pressure

Dcg

xxxx

whwsxx Fn

BNL

Np

−−

+∆

=ββ

70

70)1(1 kN/m2

(tf/m2, psi)


p N F H d ys s= + −3 ( ) kN/m2 (tf/m2, psi)

c Fore End

p FC N V Lsf s F= + +028 022 015 04 0632. ( . . tan )( . sin . )α β

kN/m2 (tf/m2)

p FC N V Lsf s F= + +092 022 015 04 03332. ( . . tan )( . sin . )α β

psi

N1, N3, ∆, Lw, V, nxx, βcg, H, d, and FD are as definedin 3/8.1.1. Nh is as defined in 3/8.3.1

Bw = maximum waterline beam, in m or ftβxx = deadrise at any section clear of LCG,

degrees, not to be taken less than 10° andnot greater than 70°

psxx = side design pressure at any section clear ofLCG, in kN/m2 (tf/m2, psi)

ps = side design pressure due to hydrostaticforces, in kN/m2 (tf/m2, psi), but is not to betaken less than the following:

= 0.05N3L kN/m2 (tf/m2, psi) at or below L/15above the base line or at any height abovebase line forward of 0.125L from the stem.

= 0.033N3L kN/m2 (tf/m2, psi) above L/15above the base line, aft of 0.125L from thestem.

psf = side design pressure for forward of 0.125Lfrom the stem.

y = distance above base line, m or ft, of locationbeing considered.

L = craft length as defined in Section 3/1.1Fs = factor as given in table 3/8.1CF = 0.0125L for L < 80m (0.00381L for L < 262

ft)= 1.0 for L ≥ 80m (262 ft)

α = flare angle, the angle between a vertical lineand the tangent to the side shell plating,measured in a vertical plane at 90° to thehorizontal tangent to the side shell.

β = entry angle, the angle between a longitudinalline, parallel to the centerline and thehorizontal tangent to the side shell.

3/8.3.3 Wet Deck or Cross StructureThe wet deck design pressure is to be determined bythe greater of the following equations:

[ ] DW

Axxb

wdwdwhwwd F

H

GnH

WLBNLNp

−+

+

∆= 1)2(33.0

1

kN/m2 (tf/m2, psi)

p p Fwd bxx D= 0 20. kN/m2 (tf/m2, psi)

∆, Lw, ncg, pbxx, and FD are as defined in 3/8.1.1N1 = 0.10 (0.010, 0.069)Bw = waterline beam of one hull in m or ft.Nh = number of hullsLwd = length of wet deck, overall, in m or ft.Wwd = width of wet deck between hull sides in m or

ft.Hb = 1.0 for catamarans or hull borne surface

effect ship= 0.0 for cushion-borne surface effect ship.

GA = vertical distance, in m or ft., from lightestdraft waterline to underside of wet deck, atdesign point in question.

Hw = ]146

][[5L

L

V

Lncg +

or h1/3 (from 3/8.1.1)

whichever is greater, in m or ft.

3/8.4 Deck Design Pressures - All CraftThe design pressures, Pd, are to be as given in Table3/8.2.

3/8.5 Superstructures and Deckhouses - AllCraft

The design pressures, Pd, are to be as given in Table3/8.3.


3/8.6 Bulkhead Structure, Design Pressure - AllCraft

3/8.6.1 Tank BoundariesThe design pressure for tank boundaries is to be notless than given by the following equation:

pt = N3h kN/m2 (tf/m2, psi)

N3 = as defined in 3/8.1.1.h = greatest of the following distances in m or ft

from lower edge of plate panel or center ofarea supported by stiffener, to:

1 A point located above the top of the tank, ata distance of two-thirds the height from thetop of the tank to the top of the overflow.

2 A point located at two-thirds of the distanceto the main weather deck.

3 A point located above the top of the tank,not less than the greater of the following:

a. 0.01L + 0.15 m (0.01L + 0.5 ft)b. 0.46 m (1.5 ft)

Where L is the craft length as defined in3/1.1

The heights of overflows are to be clearlyindicated on the plans submitted for approval.

Pressurized tanks will be subject to specialconsideration.

3/8.6.2 Watertight BoundariesThe design pressure for watertight boundaries is to benot less than given by the following equation:

pw = N3h kN/m2 (tf/m2, psi)

N3 = as defined in 3/8.1.1.h = distance in m or ft from the lower edge of

plate panel or the center of area supportedby the stiffener to the bulkhead deck atcenterline.

Table 3/8.2 Deck Design Pressures, pd

Location kN/m2 tf/m2 psi

Exposed freeboard deck, and superstructure deck for 0.25Lfrom forward

0.20L + 7.6 0.020L + 0.77 0.0088L + 1.10

Freeboard deck inside enclosed superstructures, exposedsuperstructure deck aft of 0.25L forward, internal decks

0.10L + 6.1 0.010L + 0.62 0.0044L + 0.88

Enclosed accommodations decks 5.0 0.50 0.71

Concentrated deck cargo loads1 ( )W n x x1 0 5+ . ( )W n x x1 0 5+ . ( )W n x x1 0 5+ .

Enclosed store rooms, machinery spaces, etc. ( )c h n x x1 0 5+ . ( )c h n x x1 0 5+ . ( )c h n x x1 0 5+ .

Note:1) Concentrated deck cargo loads are in kN, tf, and Ltf respectively.W = deck cargo load in kN/m2 (tf/m2 or psi)nxx = average vertical acceleration at the location under consideration as defined in 3/8.1.1c = 7.04 (0.715, 0.02)h = height of enclosed store room, machinery space, etc., in m or ft.L = craft length as defined in 3/1.1

Table 3/8.3 Superstructures and Deckhouses Design Pressures

Location L = 12.2m (40 ft.) & less L > 30.5m (100 ft)

kN/m2 (tf/m2, psi) kN/m2 (tf/m2, psi)

Superstructure and Deckhouse Front Plating 24.1 (2.46, 3.5) 37.9 (3.87, 5.50)

Superstructure and Deckhouse Front Stiffeners 24.1 (2.46, 3.5) 24.1 (2.46, 3.5)

Superstructure and Deckhouse Aft End and House Side Plating 10.3 (1.05, 1.5) 13.8 (1.41, 2.0)

Superstructure and Deckhouse Aft End and House Side Stiffeners 10.3 (1.05, 1.5) 10.3 (1.05, 1.5)

House Tops, Forward, Plating and Stiffeners 6.9 (0.70, 1.0) 8.6 (0.88, 1.25)

House Tops, Aft, Plating and Stiffeners 3.4 (0.35, 0.5) 6.9 (0.70, 1.0)

Note: For craft between 12.2 and 30.5m (40 and 100ft), design pressure is to be obtained by interpolation.L = craft length as defined in 3/1.1

PART 3 SECTION 9|1 Plating

PART 3 SECTION 9

Plating

3/9.1 Aluminum or Steel

3/9.1.1 GeneralThe bottom shell is to extend from the keel to thechine or upper turn of bilge. In general the side shellis to be of the same thickness from its lower limit tothe gunwale.

3/9.1.2 ThicknessThe thickness of the shell, deck or bulkhead plating isto be not less than obtained by the followingequations, whichever is greater:

a Lateral Loading

t spk

a

=1000σ

mm t spk

a

=σ

in

s = the spacing, in mm or in., of the shell, deck,superstructure, deckhouse or bulkheadlongitudinals or stiffeners.

p = design pressure in kN/m2(tf/m2, psi) given inSection 3/8

k = plate panel aspect ratio factor, given inTable 3/9.1

σa = design stress, in N/mm2 (kgf/mm2, psi),given in Table 3/9.2

b Buckling Strength1 Elastic Buckling Stress

σ EbmE

t

s=

0 92

. N/mm2 (kgf/mm2, psi)

σE = elastic buckling stress in N/mm2 (kgf/mm2,psi).

m = 4.0 for longitudinally framed shell and deckplating.

= Cs

l2

2 2

1+

, for transversely framed

shell and deck plating.E = for steel; 2.06 x 105 N/mm2 (21,000

kgf/mm2, 30 x 106 psi)for aluminum; 6.9 x 104 N/mm2 (7,000kgf/mm2,10 x 106 psi)

tb = thickness of plating in mm or in.s = shorter side of plate panel in mm or in.l = longer side of plate panel in mm or in.

C2 = 1.21 where stiffeners are T-sections or anglebars

= 1.10 where stiffeners are bulb plates= 1.05 where stiffeners are flat bars

2 Critical Buckling Stress The critical bucklingstress in compression, σc, is determined asfollows:

σc = σE when σE ≤ 0.5σy

= σσσy

y

E

14

−

when σE>0.5σy

σy = yield stress of material, in N/mm2 (kgf/mm2,psi).

σE = elastic buckling stress calculated in3/9.1.2b(1)

3 Calculated Compressive Stress Thecompressive stresses are given in the followingformula

σ as w swc

F M M y

I=

+5

( ) N/mm2 (kgf/mm2,

psi)

σa = working compressive stress in panel beingconsidered, N/mm2 (kgf/mm2, psi), butgenerally not less than the following:

A

Rp SM

SMf N/mm2 (kgf/mm2, psi)

Fs = as given in Table 3/8.1c5 = 105 (105 , 322,560)Mw = wave bending moment as given in

3/6.1.1b(3), kN-m (tf-m, Ltf-ft)Msw = still water bending moment as given in

3/6.1.1b(2), kN-m (tf-m, Ltf-ft)y = vertical distance in m or ft from the neutral

axis to the considered location.I = moment of inertia of the hull girder, cm4

(in4).fp = 175 N/mm2 (24 kgf/mm2, 34,000 psi).SMR = hull girder section modulus as required in

3/6, cm2m (in2ft)SMA = section modulus of the hull girder at the

location being considered, cm2m (in2ft)


4 Permissible Buckling Stress The designbuckling stress, σc, of plate panels (as calculatedin 3/9.1.1b(2)) is to be such that:

σc ≥ σa

c Minimum Thickness The thickness of shellplating, decks and bulkheads is to be not less thanobtained from the following equations:

1 Bottom Shell

0.244.0 += KLts mm

08.0009.0 += KLts in.

0.170.0 += Ltal mm

04.0015.0 += Ltal in.

ts = required thickness for steel craft, not to betaken less than 3.5mm (0.14 in.)

tal = required thickness for aluminum craft, not tobe taken less than 4.0mm (0.16 in.)

L = craft length as defined in 3/1.1K = (ny/y)e

ny = 235 N/mm2 (24 kgf/mm2, 34,000 psi)y = specified minimum yield strength of the

material, in N/mm2 (kgf/mm2, psi), but is notto be taken greater than 0.7U or 510 N/mm2

(52 kgf/mm2, 74,400 psi), whichever is lessU = minimum tensile strength of the material

used, in N/mm2 (kgf/mm2, psi)e = 1.0 for y ≤ 235 N/mm2 (24 kgf/mm2, 34,000

psi)= 0.75 for y > 235 N/mm2 (24 kgf/mm2,

34,000 psi)2 Side Shell

0.240.0 += KLts mm

08.0009.0 += KLts in.

t Lal = +0 62 10. . mm

t Lal = +0 013 0 04. . in.ts, tal, and L are as defined in 3/9.1.2(c)(1). However,ts is not to be taken less than 3.0 mm (0.12 in.) and tal

is not to be taken less than 3.5mm (0.14 in.).3 Strength Deck

0.140.0 += KLts mm

04.0009.0 += KLts in.

t Lal = +0 62 10. . mm


is not to be taken less than 3.5mm (0.14 in.).4 Lower Decks, W.T. Bulkheads, Deep TankBulkheads

0.135.0 += KLts mm

04.0007.0 += KLts in.

t Lal = +052 10. . mm


is not to be taken less than 3.5mm (0.14 in.).5 Shell Reinforcement The thickness of theshell plating is to be increased 50% in way ofskegs, shaft struts, howse pipes etc. Bowthruster tube thickness is to be equivalent to thesurrounding shell thickness.

d Wheel Loading Where provision is to bemade for the operation or stowage of vehicles havingrubber tires, and after all other requirements are met,the thickness of steel deck plating is to be not lessthan obtained from the following equation. Requireddeck thickness for aluminum decks will be subject tospecial consideration.

+=

211.1 xxn

WkKnt mm (mm, in)

k = 8.05 (25.2, 1)K = as given in Figure 3/9.1n = 1.0 where l/s > 2.0 and 0.85 where l/s = 1.0.

For intermediate values of l/s, n is to beobtained by interpolation.

W = static wheel load in kN (tf, Ltf)nxx = average vertical acceleration at the location

under consideration as defined in 3/8.1.1a = wheel imprint dimension, in mm or in,

parallel to the longer edge, l, of the platepanel, and in general the larger wheelimprint dimension.

b = wheel imprint dimension, in mm or in,perpendicular to the longer edge, l, of theplate panel, and in general the lesser wheelimprint dimension.

s = spacing of deck beams or deck longitudinalsin mm or in.

l = length of the plate panel in mm or in.

For wheel loading, the strength deck plating thicknessis to be not less than 110% of that required by theabove equation, and platform deck plating thicknessis to be not less than 90% of that required by theabove equation.

Where the wheels are close together, specialconsideration will be given to the use of the combinedimprint and load. Where the intended operation issuch that only the larger dimension of the wheelimprint is perpendicular to the longer edge of theplate panel, b above may be taken as the larger wheelimprint dimension, in which case a is to be the lesserone.


FIGURE 3/9.1 Wheel Loading Curves of "K"

TABLE 3/9.1 - Aspect Ratio Coefficient for Isotropic Plates

l/s k k1

> 2.0 0.50 0.0282.0 0.497 0.0281.9 0.493 0.0271.8 0.487 0.0271.7 0.479 0.0261.6 0.468 0.0251.5 0.454 0.0241.4 0.436 0.0241.3 0.412 0.0211.2 0.383 0.0191.1 0.348 0.0171.0 0.308 0.014

Note: s = shorter edge of plate panel in mm or in.l = longer edge of plate panel in mm or in.

TABLE 3/9.2 - Design Stresses, σσσσa, Aluminum and Steel Plating

Design Stress, σa,Bottom and Side Shell Below Bulkhead

Deck with Slamming Pressure0.90σy

Bottom and Side Below Bulkhead DeckHydrostatic Pressure

0.40σy

Side Shell above Bulkhead Deck -Slamming Pressure

0.90σy

Side Shell above Bulkhead Deck - SeaPressure

0.50σy

Deck Plating - Strength Deck 0.60σy

Deck Plating - Lower Decks 0.60σy

Wet Deck Plating 0.90σy

Bulkheads - Tank Boundary 0.60σy

Bulkheads - Watertight 0.90σy

Superstructure and Deckhouses - Front,Sides, Ends, Tops

0.60σy

Note: σy = yield strength of steel or of welded aluminum in N/mm2 (kgf/mm2, psi)


3/9.3 Fiber Reinforced Plastic

3/9.3.1 GeneralThe shell, decks and bulkheads may be either singleskin or sandwich construction. Where both are used,a suitable transition is to be obtained between themwith a minimum 12: 1 taper ratio.

The bottom shell is to extend to the chine or upperbilge turn. A suitable transition is to be obtainedbetween the bottom and side shell plating. The shellthickness in way of the keel is to be 50% greater andin way of shaft struts and skegs is to be 100% greaterthan the thickness required by 3/9.3.3 equations a orb, as applicable. For this purpose, pressure Pb asobtained from 3/8.1.1 or 3/8.3.1 and actual framespacing at the location of the member are to be usedfor equation a. Suitable framing reinforcement is tobe provided in way of shaft struts. Bow thruster tubethickness is to be equivalent to the surrounding shellthickness.

The shell, deck or bulkhead laminates may be bi-directional (having essentially same strength andelastic properties in the two in-plane principal axes ofthe shell, deck or bulkhead) or uni-directional (havingdifferent strength or elastic properties in the twoprincipal axes of the shell, deck or bulkhead panels).Bonding angles or tapes are to have essentially samestrength and elastic properties as the plating laminatebeing bonded, and are in general to be in accordancewith 3/14.

3/9.3.2 Fiber ReinforcementThe basic laminate given in 2/5 or other approvedlaminate of glass, aramid or carbon fiber in mat,woven roving, cloth, knitted fabric or non-woven uni-directional reinforcing plies may be used. Equivalentstrength and thickness of other than E-glass baselaminate is to be assessed in a laminate stackprogram on the basis of first ply failure, see Appendix3/C for guidance. For the shell and deck a sufficientnumber of plies are to be layed-up with the warp inthe 0° (longitudinal) axis. Warp and fill directionsare to be aligned parallel to the respective edges ofthe shell and deck panels as closely as practicable.Depending on the directionality and fiber orientationof these plies, other plies may be required orpermitted in the 90° (transverse) axis; reinforcingplies in other axes such as + 45° (diagonal) may alsobe used, when approved.

Where the strength and stiffness in the twoprincipal axes of the panel are different, panelbending in each of the panel principal axes is to beconsidered. See 3/9.3.3b and 3/9.3.4b.

3/9.3.3 Single Skin Laminatea With Essentially Same Properties in 0°°°° and

90°°°° Axes The thickness of the shell, deck orbulkhead plating is to be not less than given by thefollowing equations:

1 All Plating

t scpk

a

=1000σ

mm t scpk

a

=σ

in

2 All Plating

t scpk

k E F

= 1

2

3

1000 mm t sc

pk

k E F

= 1

2

3 in

3 Strength deck and shell

( )t k c L q= +3 1 10 26. mm

( )t k c L q= +3 1 10 0031. in.

L is generally not to be taken less than 12.2m (40 ft).

4 Strength deck and bottom shell

ts

k E

SM

SMb

uc

c

R

A

=0 6. σ

in mm or in.

s = the spacing of the shell or deck longitudinalsor superstructure, deckhouse or bulkheadstiffeners in mm or in., it is always to be thelesser dimension of the unsupported platepanels.

c = factor for plate curvature in the directionparallel to s, given by (1-A/s), but is not tobe taken less than 0.70.

A = distance in mm or in. measuredperpendicular from the chord length, s, tothe highest point of the curved plate arcbetween the panel edges.

p = design pressure given in Section 3/8k or k1= coefficient varying with plate panel aspect

ratio as given in Table 3/9.1kb = 2.5 with longitudinal framing

= 2.5 with transverse framing and panel aspectratio of 1.0

= 1.0 with transverse framing and panel aspectratio of 2.0 to 4.0

σa = design stress given in Table 3/9.4k2 = for bottom plating; 0.015 for patrol boats

and similar service craft, 0.01 for other craft.= for side plating; 0.020 for patrol boats and

similar service craft, 0.015 for other craft.= for superstructures and deckhouse fronts;

0.025= for other plating; 0.010

EF = flexural modulus of laminate, in N/mm2

(kgf/mm2, psi), in the direction parallel to s.q1 = 170/F (17.5/F, 25,000/F)L = craft length in m or ft as defined in 3/1.1


c1&k3 = factor for service and location, given inTable 3/9.3

Ec = compressive modulus of elasticity in N/mm2

(kgf/mm2, psi)F = minimum flexural strength of laminate, in

N/mm2 (kgf/mm2, psi)σuc = minimum compressive strength of laminate

in N/mm2 (kgf/mm2, psi)SMR = required hull-girder section modulus given

in Section 3/6SMA = proposed hull-girder section modulus of

midship section.

TABLE 3/9.3 - Fiber Reinforced Plastic Factor c1

and k3

c1 k3

mm (in.)BottomShell

Side Shell& Deck

Unrestricted Service3.2 (0.125) 1.1 1.0

Restricted Service5.7 (0.225) 1.2 1.0

TABLE 3/9.4 - Design Stresses for FRP, σσσσa

Bottom Shell 0.33σu

Side Shell 0.33σu

Decks 0.33σu

Superstructure and Deckhouses -Front, Sides, Ends, and Tops

0.33σu

Tank Bulkheads 0.33σu

Watertight Bulkheads 0.50σu

For single skin laminates:σu = minimum flexural strength, in N/mm2 (kgf/mm2,

psi)For sandwich laminates:σu = for shell or deck outer skin, minimum tensile

strength, in N/mm2 (kgf/mm2, psi)σu = for shell or deck inner skin, minimum

compressive strength, in N/mm2 (kgf/mm2, psi)σu = for bulkheads, lesser of tensile or compressive

strength, in N/mm2 (kgf/mm2, psi)Note: σu is to be verified from the approved test results.See 2/5.5

b With Different Properties in 0°°°° and 90°°°° AxesFor laminates with different strength and elasticproperties in the 0° and 90° axes where the strength isless or the stiffness greater in the panel directionperpendicular to s, the thickness is to be also not lessthan given by the following equations:

1. t scpks

as

=1000σ

mm

t scpks

as

=σ

in

2. t scpk E

El

al

l

s

=1000

4

σ mm

t scpk E

El

al

l

s

=σ

4 in

s, c, and p as defined in 3/9.3.3ks, kl = coefficient for plate panel aspect ratio,

given in Table 3/9.5σas = design stress, given in Table 3/9.4, based on

strength properties in the direction parallelto s.

Es = flexural modulus of laminate, in N/mm2

(kgf/mm2, psi) in the direction parallel to s.σal = design stress, given in Table 3/9.4, based on

strength properties in the directionperpendicular to s.

El = flexural modulus of laminate, in N/mm2

(kgf/mm2, psi) in the directionperpendicular to s.

TABLE 3/9.5 Aspect Ratio Coefficient forOrthotropic Plates

(l/s) E Es l/4 ks kl

> 2.0 0.500 0.3422.0 0.497 0.3421.9 0.493 0.3421.8 0.487 0.3421.7 0.479 0.3421.6 0.468 0.3421.5 0.454 0.3421.4 0.436 0.3421.3 0.412 0.3381.2 0.383 0.3331.1 0.348 0.323

< 1.0 0.308 0.308

3/9.3.4 Sandwich Laminatea Laminate with essentially same bending

strength and stiffness in 0°°°° and 90°°°° axes In generalthe outer and inner skins are to be similar in lay-upand in strength and elastic properties. Specialconsideration will be given where this is not the case.In general, single skin laminate is to be used in wayof the keel and in way of hull appendages such asshaft struts, skegs and rudders and in way of deckfittings, bolted connections, and other areas ofconcentrated local loads.


The section modulus and moment of inertia aboutthe neutral axis of a strip of sandwich panel, 1 cm (1in.) wide are to be not less than given by thefollowing equations:

1.( )

SMsc pk

oao

=×

2

56 10 σ cm3

( )SM

sc pko

ao

=2

6σ in3

2.( )

SMsc pk

iai

=×

2

56 10 σ cm3

( )SM

sc pki

ai

=2

6σ in3

3.( )

tcEk

pkscI

25

13

10120 ××= cm4

( )tcEk

pkscI

2

13

12= in4

s, c, p, k, k1 and k2 as defined in 3/9.3.3

SMo = required section modulus, in cm3 or in3, toouter skin.

SMi = required section modulus, in cm3 of in3, toinner skin.

I = required moment of inertia, in cm4 or in4

σao = design stress, for outer skin, given inTable 3/9.4, based on strength of outerskin in direction parallel to s.

σai = design stress, for inner skin, given inTable 3/9.4, based on strength of innerskin in direction parallel to s.

Etc = 0.5(Ec + Et)Ec = mean of compressive modulii of inner and

outer skins, in N/mm2 (kgf/cm2, psi)Et = mean of tensile modulii of inner and outer

skins, in N/mm2 (kgf/cm2, psi)

b Laminates with different bending strengthand stiffness in 0°°°° and 90°°°° axes Where the strengthis less or the stiffness greater in the directionperpendicular to s, the section modulus and momentof inertia about the neutral axis of a strip of sandwich,1 cm (1 in.) wide are also to be not less than given bythe following equations:

1. In direction parallel to s

( )SM

sc pko

s

aso

=×

2

56 10 σcm3

( )SM

sc pko

s

aso

=2

6σin3

2. In direction parallel to l

( )SM

sc pk E

Eol

alo

l

s

=×

2

56 10 σcm3

( )SM

sc pk E

Eol

alo

l

s

=2

6σ in3


( )SM

sc pki

s

asi

=×

2

56 10 σ cm3

( )SM

sc pki

s

asi

=2

6σ in3

4. In direction parallel to l

( )SM

sc pk E

Eil

ali

l

s

=×

2

56 10 σ cm3

( )SM

sc pk E

Eil

ali

l

s

=2

6σ in3


( )I

sc pk

k Es

=×

3

1

52120 10

cm4

( )I

sc pk

k Es

=3

1

212 in4

s, c, p, k1, k2 and Etc as defined in 3/9.3.3

SMo = required section modulus, in cm3 or in3,to outer skin.

SMi = required section modulus, in cm3 or in3,to inner skin.

kl, ks = modified coefficient for plate panelaspect ratio, given in Table 3/9.5.

σaso = design stress, for outer skin, given inTable 3/9.4 based on strength propertiesin direction parallel to s.


σalo = design stress, for outer skin, given inTable 3/9.4 based on strength propertiesin direction perpendicular to s.

σasi = design stress, for inner skin, given inTable 3/9.4 based on strength propertiesin direction parallel to s.

σali = design stress, for inner skin, given inTable 3/9.4 based on strength propertiesin direction perpendicular to s.

Es = 0.5 (Ets + Ecs)El = 0.5 (Etl + Ecl)Ets, Ecs = respectively mean of tensile modulii of

inner and outer skins, and mean ofcompressive modulii of inner and outerskins, in N/mm2 (kgf/cm2, psi) indirection parallel to s.

Etl, Ecl = respectively mean of tensile modulii ofinner and outer skins, and mean ofcompressive modulii of inner and outerskins, in N/mm2 (kgf/cm2, psi) indirection parallel to l.

c Shear Strength The thickness of core andsandwich laminate is to be not less than given by thefollowing equation. Special consideration will begiven where cores differing from those in 2/5 areproposed. See also 3/9.3.4e for minimum thicknessof skin.

d d pso c+=

2 1000

ντ

mm d d pso c+ =

2

ντ

in.

do = overall thickness of sandwich, excluding gelcoat, in mm or in.

dc = thickness of core, in mm or in.ν = coefficient varying with plate panel aspect

ratio, given in Table 3/9.6, Where the elasticproperties of the skins are different in theprincipal axes, ν is to be taken not less than0.5.

s = lesser dimension of plate panel, in mm or in.p = design pressure in kN/m2 (tf/m2, psi) as

defined in Section 3/8.τ = design stress, in N/mm2 (kgf/mm2, psi) as

shown in Table 3/9.7.

Where cores are scored to facilitate fitting, thescores are to be filled with putty or resin.

The density of polyvinyl chloride foam cores inthe shell plating is to be not less than given in thefollowing table:

Location Density

kg/m3 (lbs/ft3)

MinimumDensity

kg/m3 (lbs/ft3)

Bottom forward of0.4LWL; V≥ 25 kts

4dc (6.4dc) 120 (7.5)

Bottom forward of0.4LWL; V< 25 kts

4dc (6.4dc) 100 (6.25)

elsewhere; V ≥ 25 kts 3dc (4.8dc) 100 (6.25)

elsewhere; V < 25 kts 3dc (4.8dc) 80 (5.00)

Side forward 0.4LWL 2.5dc (4.0dc) 100 (6.25)

elsewhere 2.0dc (3.2dc) 80 (5.0)

TABLE 3/9.6 - Coefficient νννν for FRP SandwichPanels Shear Strength

Plate Panel Aspect Ratiol/s

ν

> 2.0 0.5002.0 0.5001.9 0.4991.8 0.4991.7 0.4941.6 0.4901.5 0.4841.4 0.4781.3 0.4661.2 0.4551.1 0.4371.0 0.420

s = shorter edge of plate panel, in mm or in.l = longer edge of plate panel, in mm or in.

Note: Values of ν less than 0.5 may be used only where theinner and outer skins have essentially the same strength andelastic properties in the 0° and 90° axes.

TABLE 3/9.7 Core Shear Design Strength

Core Material Design Core Shear Strength

Balsa Wood 0.3τu

PVC* 0.4τu

* may be taken as 0.55τu where sheer elongationexceeds 40%.

τu = minimum core shear strength, in N/mm2

(kgf/mm2, psi)

d Skin Stability The skin buckling stress σc givenby the following equation, is in general to be not lessthan 2.0 σai and 2.0 σao

σ c s cc ccE E G= ⋅ ⋅0 63.

Es = compressive modulus of skins, in N/mm2

(kgf/mm2, psi) in 0° and 90° in-plane axis ofpanel.

Ecc = compressive modulus of core, in N/mm2

(kgf/mm2, psi) perpendicular to skins.


Gcc = core shear modulus, in N/mm2 (kgf/mm2,psi) in the direction parallel to load.

e Minimum Skin Thickness After all otherrequirements are met, the skin thicknesses oflaminates complying with basic laminaterequirements of 2/5 are in general to be not less thangiven by the following equations.

tos=0.35k3 (C1 + 0.26L) mmtos= 0.35k3 (C1 + 0.0031L) in.

tis=0.25k3 (C1 + 0.26L) mmtis= 0.25k3 (C1 + 0.0031L) in.

where:tos = thickness of outer skin in mm or in.tis = thickness of inner skin in mm or in.k3, C1= factors for service and location, given in

Table 3/9.3L = craft length in m (ft), as defined in 2.1,

generally not to be taken as less than 12.2 m(40 ft).

f Wheel Loading Special consideration will begiven to the required thickness where provision ismade for the operation or stowage of vehicles havingrubber tires after all other requirements are met.

PART 3 SECTION 10|1 Internals

PART 3 SECTION 10

Internals

3/10.1 Aluminum and Steel

3/10.1.1 GeneralStructural arrangements and details are to be inaccordance with Sections 3/12 and 3/14. Reference is tobe made to 1/1.5.2 regarding the requirement to performdirect analysis to verify the design of the main supportingstructural components, which for example support theplating and plating stiffeners. The scantlings obtained bythe application of the equation in this section are to beconsidered minimum values. The purposes of directanalysis are to confirm the adequacy of the formula basedscantlings, or to provide the basis for increasing the initialscantlings to the values required based on allowable stresslimits.

3/10.1.2 Strength and Stiffnessa Section Modulus The ends of members are to be

effectively attached to the supporting structure. Thesection modulus of each longitudinal, stiffener, transverseweb, stringer and girder is to be not less than given by thefollowing equation:

SMpsl

a

=×83 3 2.

σ cm3 SM

psl

a

=×144 2

σ in3

where:

p = design pressure in kN/m2 (tf/m2, psi), given in3/8.1

s = spacing in m or ft, of longitudinal, stiffener,transverse web or girder, etc.

l = length, in m or ft, of the longitudinal, stiffener,transverse web or girder, between supports;where bracketed end connections are supportedby bulkheads, l may be measured onto thebracket, the distance given on Fig. 3/2.1,provided both bracket arms are about the samelength. Where transverse members span chinesor "knuckles", l is to be measured as shown inFigures 3/10.1 and 3/10.2.

σa = design stress, in N/mm2 (kgf/mm2, psi) as givenin Table 3/10.1

Stiffeners without end attachments are permitted onwatertight bulkheads provided the section modulus isincreased by 50%.

TABLE 3/10.1 - Design Stress, σσσσa

Location Steel andAluminum

FRP

Bottom Longitudinals - SlammingPressure

0.65σy1 /

0.55σy2

0.33σu

Bottom Longitudinals - SeaPressure

0.30σy 0.33σu

Side Longitudinals - SlammingPressure

0.60σy 0.40σu

Side Longitudinals - Sea Pressure 0.50σy 0.40σu

Deck Longitudinals - StrengthDecks

0.33σy 0.40σu

Deck Longitudinals - Other Decks 0.40σy 0.40σu

Bottom Transverse - SlammingPressure

0.80σy 0.33σu

Bottom Transverses - Sea Pressure 0.50σy 0.33σu

Side Transverses - SlammingPressure

0.80σy 0.33σu

Side Transverses - Sea Pressure 0.50σy 0.33σu

Deck Transverses - Strength Deck 0.75σy 0.33σu

Deck Transverses - Other Decks 0.75σy 0.33σu

Watertight Bulkheads 0.75σy 0.50σu

Tank Bulkheads 0.60σy 0.33σu

Superstructure and Deckhouse 0.70σy 0.33σu

σy = minimum yield strength, unwelded condition inN/mm2 (kgf/mm2, psi). For aluminum, minimum yieldstress, welded condition in N/mm2, (kgf/mm2, psi)

σu = ultimate tensile strength in N/mm2 (kgf/mm2, psi)

Notes:1) Craft less than 50m (164 ft) in length.2) Craft equal to and greater than 50m (164 ft) in length.

b Moment of Inertia The moment of inertia of eachlongitudinal, stiffener, transverse web, stringer or girder,including the plating to which it is attached, is to be notless than given by the following equation:

Ipsl

K E=

260 3

4

cm4 Ipsl

K E=

54 3

4

in4


p, s, and l are as given in 3/10.1.2.

K4 = 0.0015 for shell and deep tank girders, stringersand transverse webs, constructed of steel.

= 0.0011 for deck girders and transversesconstructed of steel.

= 0.0021 for shell and deep tank stringers andtransverse webs constructed of aluminum.

= 0.0018 for deck girder and transversesconstructed of aluminum.

E = tensile or compressive modulus, in N/mm2

(kgf/mm2, psi) representative of the basic valueused in the moment of inertia calculation.

3/10.1.3 BucklingThe moment of inertia of the deck or shell longitudinaltogether with attached plating is not to be less than tosatisfy the following criteria:

a Elastic Buckling Stress

σ EaEI

C Al=

32

N/mm2 (kgf/mm2, psi)

σE = ideal elastic buckling stress in N/mm2 (kgf/mm2,psi)

E = 2.06 x 105 N/mm2 (21,000 kgf/mm2, 30 x 106 psi)for steel

Ia = moment of inertia, cm4 (in4) of longitudinaltogether with attached plating.

C3 = 1000 (1000, 144)A = cross-sectional area in cm2 (in2)of longitudinal

together with attached plating.l = span of longitudinal in m or ft

b Critical Buckling Stress The critical bucklingstress in compression, σc, is determined as follows:

σc = σE when σE ≤ 0.5σy

= σσσy

y

E

14

−

when σE>0.5σy

σy = minimum yield strength, N/mm2 (kgf/mm2, psi)σE = ideal elastic buckling stress calculated in

3/10.1.3a

c Calculated Compressive Stress

σ as w ws

a

cF M M

Iy=

+5 N/mm2 (kgf/mm2, psi)

σa = working compressive stress in panel beingconsidered, N/mm2 (kgf/mm2, psi), but generallynot less than the following:

CSM

SMR

A1 N/mm2 (kgf/mm2, psi)

c5 = 105 (105, 322,560)Fs is as given in Table 3/8.1.Mw = wave bending moment as given in 3/6.1.1b(3),

kN-m (tf-m, Ltf-ft)Msw = still water bending moment as given in

3/6.1.1b(2), kN-m (tf-m, Ltf-ft)y = vertical distance in m or ft from the neutral axis

to the considered location.I = moment of inertia of the hull girder, cm4 (in4)C1 = 175 N/mm2 (17.84 kgf/mm2, 25,380 psi)SMR = hull girder section modulus as required in 3/6,

cm2m (in2ft)SMA = section modulus of the hull girder at the location

being considered, cm2m (in2ft)

d Design Buckling Stress The design buckling stress,σc, of the shell or deck longitudinal is to be such that:

σc ≥ βσa

β = 1.0 for web plating of stiffeners (local buckling)= 1.1 for stiffeners

3/10.1.4 ThicknessThe thickness of the webs and face bars of structuralmembers is not to be less than determined by thefollowing equations:

a Webs

td

Cw y

d

=σσ

mm (in.)

t = total required thickness in mm or in.dw = depth of the web in mm or in.C = 70 for steel members

= 50 for aluminum membersσy = minimum yield strength of steel or aluminum in

the unwelded condition, N/mm2 (kgf/mm2, psi)σd = for steel members; 235 N/mm2 (24 kgf/mm2,

34,000 psi)= for aluminum members; 127.6 kN/mm2 (12.76

kgf/mm2, 18,500 psi)


The web thickness is also not to be less than thefollowing:

tpsl

dw a

= 1000

2 τ mm

awd

pslt

τ2

144= in.

t = total required thickness in mm or in.p = design pressure in kN/m2 (tf/m2, psi) as given in

Section 3/8s = width of shell or deck supported by the member

in m or ftl = length of member in m or ftdw = depth of the web in mm or in.τa = design shear stress in N/mm2 (kgf/mm2, psi)

b Face Bars and Flat Bars

td

Cw y

d

=σσ

mm (in.)

t = total required thickness in mm or in.dw = depth of the flat bar or unsupported width of face

bar in mm or in.C = 12 for steel members

= 9 for aluminum membersσy = minimum yield strength of steel or aluminum in

the unwelded condition, N/mm2 (kgf/mm2, psi)σd = for steel members; 235 kN/mm2 (24 kgf/mm2,

34,000 psi)= for aluminum members; 127.6 kN/mm2 (12.76

kgf/mm2, 18,500 psi)

3/10.1.5 AttachmentsThe lug weld attachment of the longitudinals to thetransverse webs are to have total weld throat area not lessthan the following equations:

apsl

wa

= 1000

τ mm2

aw

psla

τ144= in2

aw = tw x lw

tw = weld throat in mm or in.lw = total length of weld in mm or in.p = design pressure in kN/m2 (tf/m2, psi) as given in

Section 3/8s = width of shell or deck supported by the member

in m or ftl = length of member in m or ftτa = design shear stress in N/mm2 (kgf/mm2, psi)

Table 3/10.2 Design Stress ττττa

Location Aluminum Steel

Bottom Primary Members - SlammingPressure

0.75τyw 0.75τy

Bottom Primary Members - SeaPressure

0.50τyw 0.50τy

Side Primary Members - SlammingPressure

0.50τyw 0.50τy

Side Primary Members - Sea Pressure 0.50τyw 0.50τy

Deck Primary Members 0.50τyw 0.50τy

τyw = minimum shear yield strength, welded conditionτy = minimum shear, unwelded condition

FIGURE 3/10.1Transverse Side Frame

FIGURE 3/10.2Transverse Side Frame


3/10.1.6 Direct Analysis - Design Stresses

a General This section relates to design stresseswhen direct analysis is performed to verify the selecteddesign scantlings in accordance with 3/10.1.1.

b Equivalent Stress The total equivalent stress (σe)obtained from conventional finite element analysis is to bebased on the following equation:

σe = (σx2 + σy

2 - σxσy + 3τ xy

2) 1/2

Where σx and σy are the direct (membrane) stresses

respectively in the x and y coordinate directions of theelements, and τxy is the in-plane shearing stress.

σe is to be less than or equal to the following design stress:

steel: 0.833 σy

aluminum: 0.833 σyw

FRP: 0.367 σu

where σy , σyw , and σu are defined in association withTable 3/10.1.

c Buckling Stresses Checking Reference is to bemade to 3/10.1.3 on checks to be made when the directstress is compressive. Checks of buckling stress in case ofshearing stress are also to be performed and documentedwhen they control the design of structural elements.

3/10.3 Fiber Reinforced Plastic

3/10.3.1 GeneralThe requirements for fiber reinforced plastic apply to craftof up to 61m (200ft) in length. Special consideration willbe given to craft of greater length than this. The structuralarrangements and details are to be in accordance withSection 3/12 and 3/14. Laminates may be bi-directionalor uni-directional. Bonding angles or tapes are to complywith 3/14.

3/10.3.2 Fiber ReinforcementThe basic laminate given in 2/5, or other approvedlaminates of glass, aramid, or carbon fiber, in mat, wovenroving, cloth, knitted fabric, or non-woven uni-directionalreinforcing plies may be used. The plies are in general tobe layed-up parallel to the direction of the internal. Thestrength of the laminate in a direction perpendicular to thedirection of the internal is in general not to be less than25% of the warp strength except for the uni-directionalcaps of the flange or crown of the internal members. Inway of continuous longitudinal members, the sectionmodulus and moment of inertia of transverse members areto be attained by the shell or deck plating and that part of

the transverse member that is continuous over thelongitudinal member.

Where higher strength or higher modulus plies are used inthe flange or crown of the internal, it may be advisable toprovide similar higher strength, higher modulus local pliesin the shell or deck plating, in the direction parallel to theinternal to balance the strength and stiffness of the highstrength and high modulus plies in the flange or crown ofthe internal.

3/10.3.3 Strength and Stiffnessa Section Modulus The section modulus of each

longitudinal, stiffener, transverse web and girder includingthe plating to which it is attached is to be not less thangiven by the following equation:

SMpsl

a

=×83 3 2.

σ cm3 SM

psl

a

=×144 2

σ in3

p, s, l and σa are as defined in 3/10.1.2.

Where the shell, deck or bulkhead plating, and the websand flange and crown of the member are of differentstrength or elastic property plies, consideration is to begiven to the effect of the different modulii plies incalculating the moment of inertia and section modulus; therequired section modulus is to be considered for eachdifferent strength laminate of the member. For uni-directional laminates, strengths and modulii in thedirection parallel to the member are to be used.

b Moment of Inertia The moment of inertia of eachlongitudinal, stiffener, transverse web, stringer or girder,including the plating to which it is attached, is to be notless than given by the following equation:

Ipsl

K E=

260 3

4

cm4 Ipsl

K E=

54 3

4

in4

where p, s and l are as given in 3/10.1.2

K4 = 0.005 for shell and deep tank girders, stringersand transverse webs.

= 0.004 for deck girders and transverses.= 0.010 for all other members.

E = tensile or compressive modulus, in N/mm2

(kgf/mm2, psi) representative of the basic valueused in the moment of inertia calculation.

c Shear Area The web area, A, of the member is tobe not less than given by the following equation:

τpsl

A5.7= cm2

τpsl

A108= in2


where p, s, and l are as given in 3/10.1.2

A = net web area in cm2 or in2 at location beingconsidered.

τ = design shear stress in N/mm2 (kgf/mm2, psi) to betaken not greater than 0.4τu

τu = lesser of ultimate shear strength in N/mm2

(kgf/mm2, psi) in either warp or fill of the weblaminate.

3/10.3.4 ProportionsThe thickness of webs and flanges are to be in accordancewith 3/14.

3/10.5 Stanchions

3/10.5.1 GeneralSupports under stanchions are to be of sufficient strengthto distribute the loads effectively. Stanchions above are tobe arranged directly over stanchions below whereverpossible; where this is not possible, effective means are tobe provided for transmitting the loads to the supportsbelow. Stanchions in double bottoms and under the topsof deep tanks are to be metal and solid in cross section.Stanchions are in general not to be used in the bottom ordouble bottom structures where subject to high impactloads in service.

3/10.5.2 Stanchion LoadThe load on a stanchion is to be obtained from thefollowing equation:

W = pbs kN or tf W = 0.064pbs Ltf

W = load in kN (tf, Ltf)b = mean breadth in m rr ft of area supported.s = mean length in m or ft of area supported.p = design pressure in kN/m2 (tf/m2, psi) given in

Section 3/8. Where a stanchion supports two ormore decks, p is to be the design pressure for thedeck at the top of the stanchion plus the sum ofthe design pressures for all complete decks andone-half the design pressure for all decks ordeck-house above the deck being directlysupported.

3/10.5.3 Permissible LoadThe load a stanchion may carry is to be equal to or greaterthan the load on the stanchion obtained in 3/10.5.2. Thispermissible load is to be obtained from the followingequations:

a. Ordinary Strength Steel Stanchions

Wa = (12.09 - 0.0444l/r) A kNWa = (1.232 - 0.00452l/r) A tfWa = (7.83 - 0.345l/r) A Ltf

b. Aluminum-Alloy Stanchions

Wa = (10.00 - 0.0582l/r) Aσy /165 kNWa = (1.02 - 0.00593l/r) Aσy /17 tfWa = (6.49 - 0.452l/r) Aσy /24000 Ltf

where:

Wa = permissible load in kN (tf, Ltf)r = least radius of gyration of stanchion in cm or in.A = area of stanchion in cm2 or in2

l = unsupported length of stanchion in m or ftσy = minimum yield strength of aluminum in kN/m2

(tf/m2, psi) in the unwelded condition

The adoption of aluminum test values higher than given inPart 2, Section 4 will be subject to special consideration.

3/10.5.4 FRP Stanchions FRP stanchions will be subject to special consideration.

3/10.5.5 Support by BulkheadsBulkheads supporting girders or bulkheads fitted in lieu ofstanchions are to be stiffened to provide support not lesseffective than required for stanchions.

PART 3 SECTION 12|1 Hull Structural Arrangement

PART 3 SECTION 12

Hull Structural Arrangement

3/12.1 Structural Arrangement - All Materials

3/12.1.1 Framing, Webs, Girders, and Non-tightStructural Bulkheads

a General The shell, main weather, or freeboarddeck, and the sides and tops of long superstructuresare in general to be longitudinally framed; dependingon craft length, speed and structural stability, craftmay also be transversely framed.

Bulkheads, partial bulkheads or web frames are tobe arranged in the main hull and in longsuperstructures or deckhouses to provide effectivetransverse rigidity. They are to be provided also inthe main hull under the ends of superstructures ordeckhouses.

Longitudinal frames are to be supported bytransverse web frames, transverse bulkheads or othertransverse structure. Longitudinals are in general tobe continuous in way of transverse supportingmembers except at transverse bulkheads where theymay be intercostal provided continuity of strength andend fixity are maintained. Depending on craft lengthand details, special consideration will be given tolongitudinals being intercostal at transverse webs.With transverse framing, deck and bottom girders areto be provided. Girders may be intercostal attransverse bulkheads provided continuity of strengthis maintained and end fixity is provided.

Transverses are to be arranged as continuous webrings and girders are to be aligned with stiffeners atbulkheads. Alternative arrangements that providefixity at the ends of transverses and girders will bespecially considered.

Engines are to be supported and secured bysubstantial girders, suitably stiffened, supportedagainst tripping and supported at bulkheads.Foundations for auxiliary machinery are to providefor secure attachment of the equipment and are to beeffectively attached to the hull structure.

A substantial foundation and seating is to beprovided for the anchor winch or windlass.

b Attachments and stiffening At supportingmembers, the attachment of all internal structuralmembers is to provide end fixity, and effective loadtransmission. Special consideration will be given toreduced end fixity where the alternative structure hasequivalent strength.

The webs of all members are to be effectivelyattached to the shell, deck or bulkhead plating, totheir supporting members and to face bars.

3/12.1.2 Watertight Bulkheadsa Collision bulkhead Craft having a length, as

defined in Section 3/1, of or exceeding 15m (50ft) areto be provided with a collision bulkhead fitted notless than 0.05L, and for passenger craft not more than0.08L, abaft the stem at the design load waterline.The bulkheads are to be intact except for approvedpipe penetrations, and are to extend to the mainweather deck preferably in one plane. In craft havinglong superstructures at the forward end, the bulkheadsare to be extended weathertight to the superstructuredeck. Provided the extensions are not less than 0.05Labaft the stem at the design load waterline they neednot be fitted directly over the collision bulkhead; insuch cases, the part of the deck forming the step is tobe weathertight. Special consideration will be givento the arrangements of collision bulkheads forgovernmental service craft such as patrol boats,search and rescue craft etc.

b Engine Room The engine room is to beenclosed by watertight bulkheads extending to themain weather deck.

c Chain Locker Chain lockers located abaft ofcollision bulkheads and extending into forepeak tanksare to be watertight.

3/12.1.3 TanksThe arrangements of all integral tanks, their intendedservice, and the heights of the overflow pipes are tobe indicated clearly on the drawings submitted forapproval.

Where potable water tanks are fitted, water closetsare not to be installed on top of the tanks nor are soillines to run over the tops of the tanks. Pipescontaining non-potable liquids are not to be runthrough the tanks. Attention is directed to theregulations of national authorities that might governthe location, construction or design of such tanks.

Baffle or swash plates are to be provided.Scantlings of pressurized tanks will be subject to

special consideration.All tanks and void spaces are to be accessible for

inspection and repair.

PART 3 SECTION 12|2 Hull Structural Arrangement

3/12.1.4 Shell PlatingThe bottom shell plating is to extend to the chine orupper turn of bilge. Increases in thickness oradditional stiffening are required in way of sea inletboxes, propeller blades, skegs, shaft struts and hawsepipes.

Where a bow thruster tube is fitted it is to be notless than the surrounding shell thickness.

3/12.1.5 DecksWhere a deck is stepped or has a break, suitablescarphing or brackets are to be provided at the sideshell.

Decks passing into superstructures within the 0.5Lamidships are to be increased in way of the break.

3/12.1.6 Means of EscapeAt least two means of escape to the main weatherdeck are to be provided from the main hull spaces.They are to be as far apart as practicable, and are tobe operable from both sides.

3/12.1.7 Double Bottomsa Passenger Craft For passenger craft that are

on international voyages that operate more than fourhours at operational speed from a port of refuge are tobe fitted with a double bottom in accordance with 5/5of the Rules for Building and Classing Steel Vessels.

b Cargo Craft Cargo craft that are oninternational voyages that are more than eight hoursat operational speed from a port of refuge are to befitted with double bottoms. The inner bottoms are tobe fitted fore and aft between the peaks or as nearthereto as practicable. Where, for special reasons indesign, it may be desired to omit the double bottom,the arrangements are to be clearly indicated on theplans when first submitted for approval. A doublebottom need not be fitted in way of deep tanksprovided the safety of the ship in the event of bottomdamage is not thereby impaired. It is recommendedthat the inner bottom be arranged to protect the bilgesas much as possible and that it be extended to thesides of the craft. The scantlings of the doublebottom are to be fitted in accordance with 3/8, 3/9,and 3/10.

3/12.3 Structural Arrangements - AdditionalRequirements for Steel and AluminumAlloys

3/12.3.1 Shell PlatingThe bottom shell plating is to extend to the chine orupper turn of bilge. In general the side shell is to beof the same thickness from its lower limit to thegunwale. Increases in thickness are required in wayof skegs shaft struts hawse pipes etc. Bow thrustertube is to be equivalent to the surrounding shellthickness.

3/12.3 Structural Arrangements - AdditionalRequirements for Fiber ReinforcedPlastic Hulls

3/12.3.1 TanksIn fiber reinforced plastic construction, non-integraltanks are to be used whenever possible. Whenintegral tanks are used they are to be of single skinconstruction, the only exception is the tank topplating can be of sandwich construction. No stiffenerswithin integral tanks are to penetrate the tankboundaries. No gasoline tanks, or tanks containingpetroleum products with flash points less than 60°C(150°F) are to be fitted integrally. The design andarrangements of oil fuel tanks is to be such that thereis no exposed horizontal section at the bottom thatcould be exposed to a fire. Other fire protectionarrangements for oil fuel tanks will be speciallyconsidered. For details of fire protectionrequirements see 3/24.

All internal surfaces of FRP tanks are to becovered with chopped strand mat weighing at least600 g/m2 (2 oz/ft2). This covering is to be in additionto the scantlings required by this Guide. A suitablecoating is to be applied to this covering to prevent thecontents of the tank from impregnating thesurrounding laminates. The sides, tops, and baffles ofintegral tanks are to have all connections taped onboth sides. Fresh water tanks are to be coated with anon-toxic and non-tainting coat of resin that isrecommended by the resin manufacturer for potablewater tanks. Where outfit items are to be laminatedto the tank surface, the heavy coating of resin is to beapplied afterwards and the laminated brackets sealedto prevent the ingress of moisture. The scantlings ofintegral oil fuel and water tanks are to be inaccordance with 3/9 and 3/10. Integral tanks are tobe tested in accordance with Table 1/2.1.

PART 3 SECTION 14|1 Arrangement, Structural Details and Connections

PART 3 SECTION 14

Arrangement, Structural Details andConnections3/14.1 Structural Details

3/14.1.1 Aluminum and Steela General Structural details are to be designed

and constructed to minimize hard spots, notches andother structural discontinuities. Openings in webs,girders and other structural internal members are tobe arranged clear of concentrated loads or areas ofhigh stresses; slots in transverses and girders forlongitudinals or beams in such locations are to befitted with collars. Care is to be taken to ensurestructural continuity; sharp corners and abruptchanges in section are to be avoided; toes of bracketsand ends of members are not to terminate on platingwithout attachment to an adjacent member, unlessspecially approved.

b Longitudinals Deck, bottom and inner bottomlongitudinals are in general to be continuous unlessspecially approved otherwise, but in way ofbulkheads they may be intercostal provided continuityof strength and end fixity are maintained by the endbrackets. The ends of all internal structural membersare to provide end-fixity and load transmission to thesupporting member. Departures from this may beconsidered where the alternative structure hasequivalent strength.

c Girders and Transverses Girders andtransverses are to have depths not less than twice thedepth of slots for longitudinals and beams or otheropenings. Transverses are to be arranged ascontinuous web rings, girders are to be aligned withstiffeners at bulkheads, alternative arrangements thatprovide fixity at the ends of transverses and girderswill be specially considered.

d Openings Access and lightening holes withsuitably radiuses corners are to be arranged asnecessary and clear of areas of load concentration orhigh stresses. Their depths and lengths are generallynot to exceed respectively, 0.5 and 0.75 the depth ofthe members. Air and limber holes are to be arrangedto eliminate air pockets and avoid any accumulationof water or other liquids. In general limber holes areto be not less than 40 mm (1 1/2 in.) radius nor morethan 1/3 the depth of the member.

e Bi-metallic Connections In aluminumconstruction, where bi-metallic connections areunavoidable, suitable insulation is to be provided.

Where in direct contact with aluminum, wood is to besuitably coated, see Section 3/21.

3/14.1.2 Fiber Reinforced Plastica General Structural continuity is to be

maintained and where changes in thickness orstructural section occur, they are to be gradual toprevent notches, hard spots and other structuraldiscontinuities. The requirements of d, and e, belowand of 3/14.3 and 3/14.5 are for the basic laminategiven in 2/5; special consideration will be givenwhere other laminates or resins are used. The ends ofall internal structural members are to provide end-fixity and load transmission to the supportingmember, departures from this may be consideredwhere the alternative structure has equivalentstrength.

b Changes in Laminate Thickness A gradualtaper is to be used for all changes in laminatethickness. Where the construction changes fromsandwich laminate to a solid laminate, the thicknessof the core material is in general, to be reduced by agradual taper of not less than 2:1.

c Openings Holes and Raw Edges Access andlightening holes with suitably radiuses corners, are tobe arranged as necessary and clear of areas of loadconcentration or high stresses. Their depths andlengths are generally not to exceed, respectively, 0.5and 0.75 the depths of the members. Air and limberholes are to be arranged to eliminate air pockets andavoid any accumulation of water or other liquids. Ingeneral they are to be not less than 40 mm (1 1/2 in.)radius not more than 1/3 the depth of the member.All exposed edges of FRP single-skin laminates are tobe sealed with resin. Edges of sandwich panels andedges of holes in sandwich panels are to be sealedwith resin-impregnated mat. Ferrules installed insandwich panels or stiffeners for drains or wirepenetrations are to be set in bedding compound. Allhatch openings are to be supported by a system oftransverse and longitudinal stiffeners.

d Piping and Wiring in Foam Piping or wiringpassing through foam-filled spaces is to be installedin plastic tubing to facilitate removal andreplacement. The ends of the plastic tubing are to bejoined to adjacent structure with resin impregnatedmat. See Figure 3/14.1


Figure 3/14.1 Piping or Opening throughFoam Filled Space

e Stiffeners1 General Stiffeners, frames, girders, deck

beams, bulkhead stiffeners, etc. used to support FRPpanels may be entirely of FRP, FRP laid overnonstructural cores or forms, or composites of FRP orother approved structural materials such as plywoodor wood.

2 Stiffeners without effective Cores or withNonstructural Cores Stiffeners without cores or withcores not indicated in Table 2/5.1 (i.e., Balsa Woodand PVC) are to conform to Figure 3/14.2, and thethickness of the crown and web of the stiffeners is tobe not less than obtained from the followingequations:

t1 = w/20 mm or in. t = h/30 mm or in.

t1 = thickness of stiffener crown in mm or in.t = thickness of stiffener webs in mm or in.w = width of stiffener crown in mm or in.h = height of stiffener webs in mm or in.

Where the stiffeners are of laminates with propertiesdiffering from the basic laminate, the thickness is tobe modified by the factor:

7.7C

E

E = compressive modulus of proposed laminatein kg/cm2 or psi.

C = ultimate compressive strength of proposedlaminate in kg/cm2 or psi.

Figure 3/14.2 Proportions of Stiffeners

Where approved polyvinylchloride, balsa, or otherapproved core material is used, thicknesses less thangiven above may be accepted provided the bucklingstresses of the stiffener skins comply with thebuckling stress criteria in 3/9.3.4d are met.

Hat-section stiffeners constructed by laying FRPover premolded FRP forms (Figure 3/14.3) are toconform with Figure 3/14.2 and the above equations;the premolded forms may be considered structurallyeffective if their physical properties are at least equalto those of the overlay laminates.

Figure 3/14.3 Premolded FRP Form

Premolded stiffeners bonded to the laminates withFRP angles, flanges or tapes (Figure 3/14.4) are alsoto conform to Figure 3/14.2 and the above equations.The thickness of each bonding angle flange or tape isto be not less than the thickness of the webs of thestiffener, and the legs of the bonding angle, flange ortape are to be of equal length in accordance withSection 3/14.5. Joints in premolded stiffeners are tobe scarphed and spliced or otherwise reinforced tomaintain the full strength of the stiffeners.


Figure 3/14.4 Premolded Stiffener

The thickness may be less than obtained from theabove equation if these members are suitablystiffened and provided with adequate lateral stability.The required minimum flange or tape laps onto suchmembers, as shown in Figure 3/14.2, if greater than50 mm (2 in.), need not exceed 10t.

f Girders and Longitudinal Frames Girders andlongitudinal frames are to be continuous throughfloors and web frames. Except in way of integral-tank end bulkheads, girders and longitudinal framesare also to be continuous through transversebulkheads. Where such members are intercostal,attention is to be given to minimizing structuraldiscontinuities

An acceptable type of continuous girder andlongitudinal-frame FRP connection is shown inFigure 3/14.5. The laps of the connections onto thesupporting structure are to be not less than the over-all widths of the structural members includingflanges, and the thicknesses of the connections are tobe not less than the thicknesses of the structural-member flanges or tapes.

Figure 3/14.5 Connection ofLongitudinals to Transverses

g Engine Foundations The engine beds are tobe of thicknesses and widths appropriate to theholding-down bolts, are to be set in mat putty or resinputty to assure uniform bearing against the girders,and are to be bolted through the webs of the girders.Figure 3/14.6 shows several typical, acceptableengine foundations.

Figure 3/14.6 Engine Foundations


h Deck Fittings Deck fittings such as cleats andchocks are to be bedded in sealing compound orgasketed, through-bolted, and supported by eitheroversize washers or metal, plywood or wood backingplates. Where washers are used, the laminate in wayof the fittings is to be increased at least 25% inthickness.

i Through Hull Penetrations Generally allthrough hull penetrations are to be formed by solidFRP laminates. When sandwich construction is usedfor the hull, the core material is to be completelysealed off from the through hull penetration. Allthrough hull penetrations are to be taped on bothsides of the penetration.

k Boundary Angles, Flanges or Tapes1 FRP to FRP Secondary bonding of FRP

components by means of double boundary angles,flanges or tapes is to be in accordance with 2/5.Typical boundary angles for FRP components areshown in Figure 3/14.7. At the end connections ofsandwich laminates the core shear strength is to beeffectively developed. The thickness of eachboundary angle, flange or tape having similar strengthto the members being connected is to be not less thanobtained from the following:

Single-skin to Single-skin One-half the thicknessof the thinner of the two laminates being joined.

Sandwich to Sandwich The greater of the meanthicknesses of the skins of the sandwich panels beingattached.

Sandwich to Single Skin Either one-half thethickness of the single-skin laminate or the meanthickness of the skins of the sandwich panel beingattached, whichever is less.

The thickness of each FRP-to-FRP boundary anglealso is to be not less than obtained from the followingequation:

t = 0.105L + 1.11 mm t = 0.00133L + 0.044 in

Where:

L = length, in m or ft, as defined in 3/1.1; need notbe taken as more than 46.6 m (153 ft).

The width of each flange, not including end taper is tobe not less than 10 times the thickness given aboveand including the end taper, 13 times the thicknessgiven above, and in general not less than 50mm (2in.)

Figure 3/14.7 Boundary Angles for FRPComponents

2 Plywood or Wood to FRP Plywoodbulkheads are to be bedded in foam, a slow-curingpolyester putty, a microballoon-and-resin mixture, orother approved material. Boundary angles of FRP areto be applied over fillets made of the beddingmaterial. The nominal size, w, of each fillet is to be9.5 mm to 12.5 mm (0.375 in. to 0.50 in.) Theboundary angles are to be at least equal in thicknessto one-half the thickness of the laminate, and thewidth of each flange is to be as shown in Figure3/14.8. Secondary bonding of these angles to FRP isto be in accordance with 2/5.

Figure 3/14.8 Boundary AnglesConnecting Plywood or Wood To FRP

3/14.3 Welded and Mechanical Connections3/14.3.1 Steel and Aluminum

a General Components may be fastened byeither welding or rivets. For welding see Sections3/23, 2/3 and 2/4.

b Expanding Rivets Rivets of the expandingtype (blind or "pop" rivets) may be used for lightlyloaded connections where lack of accessibilityprohibits the use of through fastenings. Such rivetsare not to be used for joining components having atotal thickness exceeding 12.5 mm (0.50 in.), and arenot to be used for joining decks to hulls except astemporary or unstressed fastenings installed for thesake of convenience or speed during assembly.

c Conventional Rivets Conventional rivets,where used, are to be subject to special consideration,and are to be of the cold-driven type. Washers,essentially of the same material as the rivets, are to beinstalled under both the heads and the points.


3/14.3.2 Fiber Reinforced Plastica General Components may be fastened with

bolts, machine screws, or self-tapping screws. Wheremachine screws or self-tapping screws are used, theyare not to have countersunk heads. Shanks of allthreaded fastenings are to be long enough to passthrough the joints. Where watertight joints arerequired, suitable sealants or bedding compounds areto be used in addition to the fastenings. Mechanicalfastenings are to be of material suitable for the serviceintended and are to be either galvanically compatiblewith the materials being fastened or provided with thenecessary insulation. Brass fastenings are not to beused. Non corrosion-resistant fastenings are to begalvanized. Fastenings used with aluminum alloysare to be austenitic corrosion-resistant (stainless) steelor suitable aluminum alloy. Sizes and specificationsare to be indicated on the submitted plans. Thediameter of a fastening is not to be less than thethickness of the thinner component being fastened,with a minimum diameter of 6 mm (0.24 in.)

b Bolts and Machine Screws Bolts or machinescrews are to be used where accessibility permits.The diameter of each fastener is to be at least equal tothe thickness of the thinner component beingfastened. Bolts and machine screws less than 6.5 mm(0.25 in.) in diameter are not to be used. Where d isthe fastener diameter, fastener centers are to bespaced at a minimum of 3d apart and are to be set infrom edges of laminates a minimum of 3d.

Generally in fiber reinforces plastic constructionall bolted connections are to be made through solidfiber reinforces plastic inserts. Where this is notpossible, all low density core material is to bereplaced with a structurally effective insert.Diameters of fastening holes are not to exceedfastening diameters by more than 0.4 mm (0.0156 in.)

Washers or backing plates are to be installedunder all fastening heads and nuts that otherwisewould bear on laminates. Washers are to measure notless than 2.25d in outside diameter and 0.1d inthickness. Nuts are to be either of the self-lockingtype, or other effective means are to be provided toprevent backing off.

Care is to be taken to ensure that the nut or othercomponent into which the bolt is screwed are ofmaterials having the same mechanical properties.Where materials of different strength are used, this isto be considered in determining the length of threadengagement between members.

Bolted connections are, in general, to be bondedalong all mating surfaces using an accepted structuraladhesive, applied in accordance with themanufacturer’s requirements.

In general, all structural, bolted connections are touse threads of bolts in accordance with therequirements in the following table.

Location Pitch1

Watertight connections below design waterline 10d

Connections in hull above design waterline todeck

15d

Hull to deck connections, bonded with approvedstructural adhesive

15d

Connections in deckhouses 20d

Deckhouse to deck connection, bonded withapproved structural adhesive

15d

Minimum distance between reeled lines of bolts 3d

Notes: 1. d is the diameter of the bolt.2. Internal boundary sealing angle is to beprovided.

All structural, single line, bolted connectionswithout adhesive bonding are to be in accordancewith the requirements in the following table.

Location Pitch1

Manhole covers to fuel tanks 6d

Manhole covers to water tanks 8d

Covers to void tanks/cofferdams 10d

Bolted access hatches in decks 10d

Bolted watertight door frames 8d

Window frames 8d

Note: 1. d is the diameter of the bolt

Bolt holes are to be drilled, without unduepressure at breakthrough, having a diametrictolerance of two percent of the bolt diameter. Wherebolted connections are to be made watertight, the holeis to be sealed with resin and allowed to cure beforethe bolt is inserted. In areas of high stress or whereunusual bolting configurations, on the basis ofequivalence with the above requirements, areproposed, testing may be required.

c Self-tapping Screws In general no self-tappingscrews are to be used in fiber reinforced plasticconstruction. Self-tapping screws having straightshanks may be used for non-structural connectionswhere lack of accessibility prohibits the use ofthrough fastenings. Where used, self-tapping screwsare to have coarse threads.

3/14.3.3 Backing Bars and Tapping PlatesThe requirements for backing plates and bars will beindividually considered, on the basis of the loadingimposed, details of which are to be indicated on thesubmitted plans. Metal plates and bars are to besuitably protected against corrosion. Tapping platesmay be encapsulated within the laminate, laminatedto or bolted to the structure. Tapping plate edges orcorners are to be suitably rounded.


3/14.5 Deck-to-Hull Joints

3/14.5.1 Weather JointsThe connection is to develop the strength of the deckand shell laminate, whichever is stronger, by either abolted or bonded connection.

Figure 3/14.9Deck-to-Hull Weather Joints

Where flanges are used, the hull flanges are to beequal in thickness and strength to the hull laminatesand the deck flanges are to be equal in strength andthickness to the deck laminates. Where bolts are usedto develop the required strength of the connection, thefaying surfaces are to be set in bedding compound,polyester putty, or other approved material.Minimum widths of overlaps, minimum boltdiameters, and maximum bolt spacing are to be inaccordance with Table 3/14.1. Intermediate valuesmay be obtained by interpolation.

FRP bonding angles, where used, are to haveflanges of the same strength and of at least one-halfthe thickness of single skin hull or deck laminate. Onsandwich laminates, they are to have the samestrength and thickness as the skin of a sandwichlaminate, based on the thicker of the two laminatesbeing connected. The widths of the flanges are to bein accordance with the widths of overlaps in Table3/14.1.

Table 3/14.1 Deck-to-Hull Joints

Metric Units:Bolt Spacing (mm)Length

of Craft(m)

MinimumWidth ofOverlap(mm)

MinimumBolt

Diameter(mm)

UnrestrictedService

RestrictedService

9 63.5 6.50 152.5 228.5

12 75.0 7.75 165.0 241.5

15 87.5 9.00 177.5 254.0

18 100.0 10.25 190.5 266.5

21 112.5 11.50 203.0 279.5

24 125.0 12.75 216.5 292.0

27 137.5 14.00 228.5 305.0

30 150.0 15.25 241.5 317.5

33 162.5 16.50 254.0 330.0

36 175.0 17.75 266.5 343.0

Inch UnitsBolt Spacing (in.)Length

of Craft(ft )

MinimumWidth ofOverlap

(in.)

MinimumBolt

Diameter(in.)

UnrestrictedService

RestrictedService

30 2.5 0.25 6.0 9.0

40 3.0 0.30 6.5 9.5

50 3.5 0.35 7.0 10.0

60 4.0 0.40 7.5 10.5

70 4.5 0.45 8.0 11.0

80 5.0 0.50 8.5 11.5

90 5.5 0.55 9.0 12.0

100 6.0 0.60 9.5 12.5

110 6.5 0.65 10.0 13.0

120 7.0 0.70 10.5 13.5

Each joint is to be protected as shown in Figure3/14.15 by a guard, molding, fender, or rail cap ofmetal, wood, rubber, plastic, or other approvedmaterial. The size and ruggedness of this protectivestrip are to be consistent with the severity of theservice for which the craft is intended. The strip is tobe installed in such a manner that it may be removedfor repair or replacement without endangering theintegrity of the deck-to-hull joint.

3/14.5.2 Interior JointsInterior decks are to be connected to the hull byshelves, stringers, or other structural members onboth sides by FRP tapes. The connection is toeffectively develop the strength of the interior deck.

3/14.7 Shell Details

3/14.7.1 KeelsPlate keels are to be not less than shown in Figure3/14.10a and 3/14.10b, and vertical keels or skegs areto be not less than shown in Figure 3/14.11. Keels orskegs are to be adequate for docking loads, which areto be provided by the designer.


Figure 3/14.10a Plate Keel in One-PieceHull

Figure 3/14.10b Plate Keel in HullMolded in Halves

Figure 3/14.11 Vertical Keel or Skeg

3/14.7.2 Chines and TransomsChines and transoms are to be not less than shown inFigure 3/14.12.

Figure 3/14.12 Chine or Transom

PART 3 SECTION 18|1 Protection of Deck Openings

PART 3 SECTION 18

Protection of Deck Openings

3/18.1 General

All openings in decks are to be framed to provideefficient support and attachment for the ends of thedeck beams. The proposed arrangement and detailsfor all hatchways are to be submitted for approval.

3/18.3 Position of Deck Openings

For the purpose of this Guide, two positions of deckopenings are defined as follows:

Position 1 Upon exposed freeboard and raisedquarter decks, and upon exposedsuperstructure decks situated forward ofa point located a quarter of the craftlength from the forward perpendicular.

Position 2 Upon exposed superstructure deckssituated abaft a quarter of the craft lengthfrom the forward perpendicular.

3/18.5 Hatchway Coamings, CompanionwaySills and Access Sills

3/18.5.1 Coaming and Sill HeightsThe heights above deck of the coamings, the sills ofcompanionways and access openings, are to be notless than given in Table 3/18.1. Where hatch coversare made of steel or other equivalent material andmade tight by means of gaskets and clamping devices,these heights may be reduced, or the coamingsomitted entirely, provided that the safety of the craftis not thereby impaired in any sea conditions. Sealingarrangements are to be weathertight if coaming isfitted, and watertight for flush covers.

3/18.7 Enclosed SuperstructuresSuperstructures are to meet the followingrequirements to be considered enclosed.Superstructures with openings which do not fullycomply with these requirements are to be consideredas open superstructures. See also 3/20.3.4

3/18.7.1 Closing AppliancesAll openings in the bulkheads of enclosedsuperstructures are to be provided with efficientmeans of closing, so that in any sea conditions waterwill not penetrate the craft. Opening and closingappliances are to be framed and stiffened so that the

whole structure, when closed, is equivalent to theunpierced bulkhead.

Doors for access openings into enclosedsuperstructures are to be of steel or other equivalentmaterial, permanently and strongly attached to thebulkhead. The doors are to be provided with gasketsand clamping devices, or other equivalentarrangements, permanently attached to the bulkheador to the doors themselves, and the doors are to be soarranged that they can be operated from both sides ofthe bulkhead.

Portlights in the end bulkheads of enclosedsuperstructures are to be of substantial constructionand provided with efficient inside deadlights. Alsosee 3/20.7 and 3/20.8

The location and means of the closing appliancesfor windows are to be in accordance with 3/20.8

3/18.7.2 Sills of Access OpeningsExcept as otherwise provided in this Guide, the heightof the sills of access openings in bulkheads at theends of enclosed superstructures is to be at least 380mm (15 in.) above the deck. See Table 3/18.1 forrequired sill heights.

3/18.7.3 Means of AccessSuperstructures are not to be regarded as enclosedunless access is provided for the crew to reachmachinery and other working spaces inside thesesuperstructures by alternate means which areavailable at all times when bulkhead openings areclosed.

3/18.9 Hatchways Closed by Covers of Steel andFitted with Gaskets and ClampingDevices

3/18.9.1 Strength of CoversThe maximum allowable stress and deflection underdesign load, w, and the minimum top plate thicknessare as follows:

maximum allowable stress = 0.235σu

maximum allowable deflection = 0.0028stop plate thickness = 0.01s; but not less than

6.0mm (0.24in.)


Position 1w= 0.097L + 7.45 kN/m2

w= 0.0099L + 0.76 tf/m2

w= 0.61L + 158.0 lbf/ft2

Position 2w= 0.0709L + 5.65 kN/m2

w= 0.00725L + 0.576 tf/m2

w= 0.450L + 118.5 lbf/ft2

w = design load in kN/m2 (tf/m2, lbf/ft2)L = length of craft in m or ft as defined in

Section 3/1, but is not to be taken less than24 m (79 ft).

s = stiffener spacing in mm or in.σu = minimum ultimate tensile strength in N/mm2

(kgf/mm2, psi)

3/18.9.2 Means for Securing WeathertightnessThe means for securing and maintainingweathertightness is to be such that the tightness canbe maintained in any sea condition. The covers are tobe hose tested in position under a water pressure of atleast 2.1 bar (2.1 kgf/cm2, 30 psi) at the time ofinstallation.

3/18.9.3 Flush Hatch CoversWhere flush hatch covers are fitted on the freeboarddeck within the forward one-fourth length, and thecraft is assigned a freeboard less than Type-B underthe International Convention on Load Lines 1966, theassumed loads on flush hatch covers are to beincrease 15% over that indicated in 3/18.9.1.

3/18.11 Hatchways Closed by Portable Covers inLower Decks or within Fully EnclosedSuperstructures

3/18.11.1 GeneralThe following scantlings are intended forconventional type covers. Those for covers of specialtypes are to be specially considered.

3/18.11.3 Steel CoversThe thickness of the plating for steel covers is not tobe less than required for lower decks as obtainedfrom 3/9.1. A stiffening bar is to be fitted around theedges as required to provide the necessary rigidity topermit the covers being handled without deformation.The effective depth of the framework is normally tobe not less than 4% of its unsupported length. Thestiffeners in association with the plating to which theyare attached are to have section modulus, SM, asdetermined by the following equation.:

SM = 7.8hsl2 cm3 SM = 0.0041hsl2 in.3

h = 'tween-deck height in m or fts = spacing of the stiffeners in m or ftl = length of the stiffener in m or ft

3/18.11.4 Wheel LoadingWhere provision is to be made for the operation andstowage of vehicles having rubber tires, the thicknessof the hatch cover plating is to be in accordance withthe Rules for Building and Classing Steel Vesselsunder 90m (295 ft) in Length, section 3/18.11.4

3/18.13 Hatchways within Open Superstructures

Hatchways within open superstructures are to beconsidered as exposed.

3/18.15 Hatchways within Deckhouses

Hatchways within deckhouses are to have coamingsand closing arrangements as required in relation tothe protection afforded by the deckhouse from thestandpoint of its construction and the means providedfor the closing of all openings into the house.

3/18.17 Machinery Casings

3/18.17.1 ArrangementMachinery-space openings in Position 1 or 2 are to beframed and efficiently enclosed by casings of amplestrength, and wherever practicable, those in freeboarddecks are to be within superstructures or deckhouses.Casings are to be of material similar to that of thesurrounding structure. Openings in exposed casingsare to be fitted with doors complying with therequirements of 3/18.7.1; the sills are to be inaccordance with 3/18.5.1 for companionways. Otheropenings in such casings are to be fitted withequivalent covers, permanently attached. Stiffenersare to be spaced at not more than 760 mm (30 in.)

3/18.17.3 Scantlings

The scantlings of exposed casings are to be similar tothose obtained for superstructures and deckhouses inaccordance with the applicable requirements ofSections 3/8, 3/9 and 3/10.

The scantlings of casings within enclosedsuperstructures or deckhouses will be speciallyconsidered.


3/18.19 Miscellaneous Openings in Freeboard andSuperstructure Decks

3/18.19.1 Manholes and ScuttlesManholes and flush scuttles in Position 1 or 2 withinsuperstructures other than enclosed superstructuresare to be closed by substantial covers capable ofbeing made watertight. Unless secured by closelyspaced bolts, the covers are to be permanentlyattached.

3/18.19.2 Other OpeningsOpenings in freeboard decks other than hatchways,machinery-space openings, manholes and flushscuttles are to be protected by an enclosedsuperstructure, or by a deckhouse or companionwayof equivalent strength and weathertightness. Any suchopening in an exposed superstructure deck or in thetop of a deckhouse on the freeboard deck which givesaccess to a space below the freeboard deck or a spacewithin an enclosed superstructure is to be protectedby an efficient deckhouse or companionway.Doorways in such deckhouses or companionways areto fitted with doors complying with the requirementsgiven in 3/18.7.1.

3/18.19.3 Escape OpeningsThe closing appliances of escape openings are to bereadily operable from each side.

TABLE 3/18.1Coaming and Sill Heights

L equal to or over 24 meters (79 feet) in length

Position 1 Position 2Hatch Coamings 600 mm (23.5 in.) 450 mm (17.5 in.)

CompanionwaySills

600 mm (23.5 in.) 380 mm (15 in.)

Access Sills 380 mm (15 in.) 380 mm (15 in.)

L under 24 meters (79 feet) in length

Position 1 Position 2Hatch CoamingsandCompanionways

450 mm (17.5 in.) 300 mm (12 in.)

Access Sills 380 mm (15 in.) 300 mm (12 in.)

Note:1 Coaming and sill heights may be reduced on craft

which have freeboard in excess of the minimumgeometric freeboard and/or a superstructure deck withheight of deck in excess of the standard height of asuperstructure.

2 For craft with L<24m, the coaming/sill height shouldbe as indicated above, unless otherwise specificallyrequested by Flag Administration.

PART 3 SECTION 20|1 Bulwarks, Rails, Ports, Portlights, Windows, and Ventilators

PART 3 SECTION 20

Bulwarks, Rails, Ports,Portlights, Windows, and Ventilators

3/20.1 Bulwarks and Guard Rails

3/20.1.1 Location and HeightsBulwarks or guard rails or a combination of both, arein general to be provided on exposed decks, and onexposed tops of superstructures and deckhouses.

The height of bulwarks and guard rails onexposed freeboard and superstructure decks is to be atleast 1 m (39.5 in.) Where this height would interferewith the normal service or operation of a craft, alesser height may be approved if adequate protectionis provided. Where approval of a lesser height isrequested, justifying information is to be submitted.

In exposed areas not traversed in the normaloperation of the craft, where it is not practical to fitbulwarks or guard rails, hand or grab rails may beconsidered.

3/20.1.2 Strength of BulwarksBulwarks are to be of ample strength for their heightand location, suitably stiffened at the top, and ifnecessary at the bottom, and supported by efficientstays or brackets.

Stays or brackets on the main weather deck are tobe spaced not more than 1.83 m (6.0 ft).

Openings in bulwarks are to be smooth-edged,with well-rounded corners.

3/20.1.3 Spacing of Guard Railsa Fixed, removable or hinged stanchions are to

be fitted at approximately 1.5 m (5 ft) apart.b At least every third stanchions is to be

supported by a bracket or stay.c The opening below the lowest course is not to

exceed 230 mm (9 in.) The distance between theremaining courses is not to be more than 380 mm (15in.)

d For craft with rounded gunwales, stanchionsare to be placed on the flat of the deck.

3/20.3 Freeing Ports

3/20.3.1 Basic AreaWhere bulwarks on freeboard decks form wells,ample provision is to be made for rapidly freeing thedecks of water and for draining them. The minimumfreeing-port area on each side of the craft for each

well 20 m (66 ft) or less in length is to be obtainedfrom the following equation:

A = 0.7 + 0.035l m2 A = 7.6 + 0.115l ft2

Where the bulwark length exceeds 20 m (66 ft):

A = 0.07l m2 A = 0.23l ft2

A = freeing-port area in m2 or ft2

l = bulwark length in m or ft but need notexceed 0.7L.

The minimum area for each well on superstructuredecks is to be one half of the area obtained from theabove equations.

If a bulwark is more than 1.2 m (3.9 ft) in height, thefreeing-port area is to be increased by 0.004 m2 permeter (0.04 ft2 per foot) of length of well for each 0.1m (1 ft) difference in height. If a bulwark is less than0.9 m (3 ft) in height, the freeing-port area may bedecreased by the same ratio. Craft receiving freeboardassignment are to have freeing port area inaccordance with the International Convention onLoad Lines.

3/20.3.2 Trunks, Deckhouses, and HatchwayCoamings

Where a craft is fitted with a trunk on the freeboarddeck, and open rails are not fitted in way of the trunkfor at least one-half its length, or where continuous orsubstantially continuous hatchway side coamings arefitted or long deckhouse exist between detachedsuperstructures, the minimum area of freeing-portopenings is to be obtained from the following table:

Breadth of trunk, deckhouseor hatchway in relation to

breadth of craft

Area of freeing portsin relation to totalarea of bulwarks

40% or less 20%75% or more 10%

The area of freeing ports at intermediate breadths isto be obtained by linear interpolation.


3/20.3.3 Superstructure DecksWhere bulwarks on superstructure decks form wells,the bulwarks are to comply with 3/20.3.1 except thatthe minimum freeing-port area on each side of thecraft for each well is to be one-half of the areaobtained in 3/20.3.1 and 3/20.3.2.

3/20.3.4 Open SuperstructuresIn craft having superstructures that are open at eitherend or both ends, adequate provisions for freeing thespaces within such superstructures are to be provided;the arrangements will be subject to special approval.

3/20.3.5 Details of Freeing PortsThe lower edges of the freeing ports are to be as nearthe deck as practicable. Two-thirds of the requiredfreeing-port area is to be provided in the half of thewell nearest the lowest point of the sheer curve.Freeing-port openings are to be protected by rails orbars in such a manner that the maximum clear verticalor horizontal space is 230 mm (9 in.). Where shuttersare fitted, ample clearance is to be provided toprevent them from jamming. Hinges are to have pinsand bearings of corrosion resistant material and ingeneral, the hinges are to be located at the top of theshutter. If the shutters are equipped with securingappliances, the appliances are to be of approvedconstruction.

3/20.5 Cargo, Gangway, or Fueling Ports

3/20.5.1 ConstructionCargo, gangway, or fueling ports in the sides of craftare to be strongly constructed and capable of beingmade thoroughly watertight. Where frames are cut inway of such ports, web frames are to be fitted on thesides of the openings, and suitable arrangements areto be provided for the support of the beams over theopenings. Thick shell plates or doublers are to befitted as required to compensate for the openings. Thecorners of the openings are to be well rounded.Waterway angles and scuppers are to be provided onthe decks in way of ports in cargo spaces below thefreeboard deck or in cargo spaces within enclosedsuperstructures to prevent the spread of any leakagewater over the decks.

Indicators showing whether the ports in the sideshell below the freeboard or superstructure deck aresecured closed or open are to be provided on thenavigation bridge.

3/20.5.2 LocationThe lower edges of cargo, gangway, or fueling-portopenings are not to be below a line parallel to thefreeboard deck at side having as its lowest point thedesigned load waterline or upper edge of theuppermost load line.

3/20.6 Bow Doors and Inner DoorsWhere steel bow doors of the visor or side-openingtype are fitted leading to complete or long forwardenclosed superstructure, bow doors and inner doorsare to meet the requirements of this subsection. Hullsupporting structure in way of the bow doors is to beable to withstand the loads imposed by the bow doorssecuring and supporting devices without exceedingthe allowable stresses for those devices, both given inthis subsection. Special consideration will be givento bow doors constructed of materials other thansteel.

3/20.6.1 ArrangementAs far as practicable, bow doors and inner doors areto be arranged so as to preclude the possibility of thebow door causing structural damage to the inner dooror to the collision bulkhead in the case of damage toor detachment of the bow door.

a Bow Doors Bow doors are to be situatedabove the freeboard deck except that where awatertight recess fitted for arrangement of ramps orother related mechanical devices is located forward ofthe collision bulkhead and above the deepestwaterline, the bow doors may be situated above therecess.

b Inner Doors An inner door is to be fitted inthe extension of the collision bulkhead required by3/12.1.2a. A vehicle ramp made watertight andconforming to 3/12.1.2a in the closed position may beaccepted for this purpose.

3/20.6.2 Securing, Locking and Supporting ofDoors

a Definitions1 Securing device A device used to keep the

door closed by preventing it from rotating aboutits hinges or its pivoted attachments to the ship.

2 Supporting device A device used to transmitexternal or internal loads from the door to asecuring device and from the securing device tothe ship’s structure, or a device other than asecuring device, such as a hinge, stopper orother fixed device, that transmits loads from thedoor to the ship’s structure.

3 Locking device A device that locks a securingdevice in the closed position.

b Securing and Supporting devices1 Bow Doors Means are to be provided to

prevent lateral or vertical movement of the bowdoors when closed. Means are also to beprovided for mechanically fixing the door in theopen position.

Means of securing and supporting the doorare to maintain equivalent strength and stiffnessof the adjacent structure.


a Clearance and packing The maximumdesign clearance between the door andsecuring/supporting devices is not to exceed 3mm (0.12 in.). Where packing is fitted, it is tobe of a comparatively soft type and thesupporting forces are to be carried by the steelstructure only.

b Visor Door Arrangement The pivotarrangement is to be such that the visor is selfclosing under external loads. The closingmoment, My, as defined in 3/20.6.6a3a is notto be less than Myo as given by the followingequation.

M Wc a b F Fyo x z= + + +01 2 2 2 2.

Where W, a, b, c, Fx and Fz are as defined in3/20.6.6.

In addition, the arrangement of the door isto be such that the reaction forces of pin orwedge supports at the base of the door doesnot act in the forward direction when the dooris loaded in accordance with 3/20.6.6a3d.

c Securing and Locking arrangementSecuring devices are to be provided with amechanical locking arrangement (self lockingor separate arrangement), or are to be of thegravity type.1 Operation Securing devices are to be

simple to operate and readily accessible.The opening and closing systems as well asthe securing and locking devices are to beinterlocked in such a way that they can onlyoperate in the proper sequence.a Hydraulic securing devices Where

hydraulic securing devices are applied, thesystem is to be mechanically lockable inthe closed position. In the event of a lossof hydraulic fluid, the securing devices areto remain locked.

The hydraulic system for securing andlocking devices is to be isolated from otherhydraulic circuits when in the closedposition.

b Remote Control Where bow doors andinner doors give access to a vehicle deck,an arrangement for remote control from aposition above the freeboard deck is to beprovided allowing closing and opening ofthe doors and associated securing andlocking of the securing and lockingdevices for every door. The operatingpanels for operation of doors are to beaccessible to authorized persons only. Anotice plate giving instructions to theeffect that all securing devices are to beclosed and locked before leaving harbor isto be placed at each operating panel and is

to be supplemented by warning indicatorlights as indicated in 3/20.6.2c2a

2 Indication/Monitoringa Indicators The indicator system is to be

designed on the fail safe principle and inaccordance with the following:1 Location and Type Separate indicator

lights are to be provided on thenavigation bridge to show that the bowdoor and inner door are closed and thattheir locking devices are properlypositioned.

The indication panel on thenavigation bridge is to be equipped witha mode selection function “harbor/seavoyage”, arranged so that an audible andvisible alarm is given if in the sea voyagecondition, the bow door or inner door isnot closed, or any of the securing devicesis not in the correct position.

Indication of the open/closed positionof every door and every securing andlocking device is to be provided at theoperating panels.

2 Indicator lights Indicator lights are tobe designed so that they cannot bemanually turned off. The indicationpanel is to be provided with a lamp testfunction.

3 Power Supply The power supply for theindicator system is to be independent ofthe power supply for operating andclosing the doors.

4 Protection of Sensors Sensors are to beprotected from water, ice formation andmechanical damage.

b Water Leakage Protection A drainagesystem is to be arranged in the areabetween the bow door and ramp and in thearea between the ramp and inner doorwhere fitted. The system is to be equippedwith an audible alarm function to thenavigation bridge for water level in theseareas exceeding 0.5m (1.6 ft.) above thecar deck level.

A water leakage detection system withaudible alarm and television surveillanceare to be arranged to provide an indicationto the navigation bridge and to the enginecontrol room of leakage through the innerdoor.

c Door surveillance Between the bow doorand the inner door a television surveillancesystem is to be fitted with a monitor on thenavigation bridge and in the engine controlroom. The system is to monitor theposition of doors and a sufficient numberof their securing devices.


3/20.6.3 Tightnessa Bow Doors Bow doors are to be so fitted as

to ensure tightness consistent with operationalconditions and to give effective protection to theinner doors.

b Inner Doors Inner doors forming part of theextension of the collision bulkhead are to beweathertight over the full height of the cargo spaceand arranged with fixed sealing supports on the aftside of the doors.

3/20.6.4 Bow Door ScantlingsBow doors are to be framed and stiffened so that thewhole structure is equivalent to the unpiercedbulkhead when closed.

a Primary Structure Scantlings of primarymembers are to be designed so that the allowablestresses indicated in 3/20.6.7a are not exceeded whenthe structure is subjected to the design loads indicatedin 3/20.6.6a1.

b Secondary Stiffeners Secondary stiffeners areto be supported by primary members constituting themain stiffening of the door. The section modulus,SM, of secondary stiffeners is to be as required by3/10.1.2. In addition, stiffener webs are to have a netsectional area not less than that obtained from thefollowing equation:

A = VQ/10 cm2 (A = VQ cm2, A = VQ/6.5 in2)

whereV = shear force in kN (tf, Ltf) in the stiffener

calculated using the uniformly distributedexternal pressure Peb given in 3/20.6.6a1

Q = as defined in 3/6.1.1a.c Plating The thickness of bow door plating is

to be not less than that required for side shell platingat the same location.

d Securing and Supporting Devices Scantlingsof securing and supporting devices are to be designedso that the allowable stresses indicated in 3/20.6.7aare not exceeded when the structure is subjected tothe design loads indicated in 3/20.6.6a2. All loadtransmitting elements in the design load path from thedoor through securing and supporting devices into theship structure, including welded connections, are tomeet the strength standards required for securing andsupporting devices. Where fitted, threaded bolts arenot to carry support forces, and the maximum tensilestress in way of the threads is not to exceed theallowable stress given in 3/20.6.7c.

In determining the required scantlings, the door isto be assumed to be a rigid body. Only those activesupporting and securing devices having an effectivestiffness in the relevant direction are to be includedand considered when calculating the reaction forceson the devices. Small or flexible devices such ascleats intended to provide load compression of the

packing material are not to be included in thecalculations.

1 Bearing Pressure The bearing pressure onsteel to steel bearings is to be calculated bydividing the design force by the projectedbearing area, and is not to exceed the allowablestress given in 3/20.6.7b.

2 Redundancy In addition to the aboverequirements, the arrangement of the securingand supporting devices is to be designed withredundancy such that in the event of failure ofany single securing or supporting device, thestresses in the remaining devices do not exceedthe allowable stresses indicated in 3/20.6.7a bymore than 20% under the above loads.

3 Visor Door Securing and Supporting DevicesSecuring and supporting devices, excluding thehinges, are to be capable of resisting the verticaldesign force given in 3/20.6.6a3c withoutstresses exceeding the allowable stresses in3/20.6.7a.

Two securing devices are to be provided atthe lower part of the door, each capable ofproviding the full reaction force required toprevent opening of the door without stressesexceeding the allowable stresses indicated in3/20.6.7a. The opening moment, Mo, to bebalanced by this force is as given in3/20.6.6a3b.

4 Side-opening Door Thrust Bearing A thrustbearing is to be provided in way of girder endsat the closing of the two doors, and is to preventone door from shifting towards the other oneunder the effect of unsymmetrical pressure.Securing devices are to be fitted to securesections thrust bearing to one another.

e Visor Door Lifting Arms and SupportsWhere visor type bow doors are fitted, calculationsare to be submitted verifying that lifting arms andtheir connections to the door and ship structure areadequate to withstand the static and dynamic forcesapplied during the lifting and lowering operationsunder a wind pressure of at least 1.5 kN/m2 (0.15tf/m2, 0.014 Ltf/ft2)

3/20.6.5 Inner Door ScantlingsScantlings of inner doors are to meet the requirementsof this paragraph. In addition, where inner doors areused as vehicle ramps, scantlings are not to be lessthan required for vehicle decks.

a Primary Structure Scantlings of primarymembers are to be designed so that the allowablestresses indicated in 3/20.6.7a are not exceeded whenthe structure is subjected to the design loads indicatedin 3/20.6.6b1.


b Securing and Supporting Devices Scantlingsof securing and supporting devices are to be designedso that the allowable stresses indicated in 3/20.6.7aare not exceeded when the structure is subjected tothe design loads indicated in 3/20.6.6b. Where fitted,threaded bolts are not to carry support forces, and themaximum tensile stress in way of the threads is not toexceed the allowable stress given in 3/20.6.7c.

The bearing pressure on steel to steel bearings isto be calculated by dividing the design force by theprojected bearing area, and is not to exceed theallowable stress given in 3/20.6.7b.

3/20.6.6 Design Loadsa Bow Doors

1 External Pressure The design externalpressure, Peb, is to be taken as indicated by thefollowing equation. Peb for craft engaged inrestricted service will be specially considered.

( )( )P nc V kLeb d= + +0 22 015 0 4 0 62

. . tan . sin .β α kN/m2 (tf/m2, Ltf/ft.2)

wheren = 2.75 (0.280, 0.0256)c = 0.0125L for craft having L < 80 m (260 ft.)

= 1.0 for other craftL = length of craft as defined in 3/1.1 in m or

ft.β = flare angle at the point to be considered,

defined as the angle between a vertical lineand the tangent to the side shell platingmeasured in a vertical plane normal to thehorizontal tangent to the shell plating. SeeFigure 3/20.1a.

α = entry angle at the point to be considered,defined as the angle between a longitudinalline parallel to the centerline and thetangent to the shell plating in a horizontalplane. See Figure 3/20.1a.

k = 1.0 (1.0, 0.305)Vd = craft design speed as defined in 3/5.2.1

2 External Forces The design external forcesconsidered in determining scantlings ofsecuring and supporting devices of bow doorsare not to be taken less than those given by thefollowing equations.

Fx = PemAx

Fy = PemAy

Fz = PemAz

whereFx = the design external force in the

longitudinal direction in kN (tf, Ltf)

Fy = the design external force in thehorizontal direction in kN (tf, Ltf)

Fz = the design external force in thevertical direction in kN (tf, Ltf)

Ax = area in m2 (ft.2) of the transversevertical projection of the doorbetween the levels of the bottom ofthe door and the upper deck orbetween the bottom of the door andthe top of the door, whichever is less.

Ay = area in m2 (ft.2) of the longitudinalvertical projection of the doorbetween the levels of the bottom ofthe door and the upper deck orbetween the bottom of the door andthe top of the door, whichever is less.

Az = area in m2 (ft.2) of the horizontalprojection of the door between thelevels of the bottom of the door andthe upper deck or between the bottomof the door and the top of the door,whichever is less.

Pem = bow door pressure, Peb, determinedusing αm and βm in place of α and β.

βm = flare angle measured at a point on thebow door l/2 aft of the stem line on aplane h/2 above the bottom of thedoor as shown in Figure 3/20.1b.

αm = entry angle measured at the samepoint as βm. See Figure 3/20.1b.

h = height in m (ft.) of the door betweenthe levels of the bottom of the doorand the upper deck or between thebottom of the door and the top of thedoor, whichever is less.

l = length in m (ft.) of the door at aheight h/2 above the bottom of thedoor.

3 Visor Door Load Casesa Closing Moment For visor doors, the

closing moment, My is to be taken asindicated by the following equation:

My = Fxa + Wc - Fzb kN-m (tf-m, Ltf-ft.)

whereFx and Fz are as defined in 3/20.6.6a2W = weight of the visor door in kN (tf, Ltf)a = vertical distance in m (ft.) from the

visor pivot to the centroid of thetransverse vertical projected area of thevisor door. See Figure 3/20.2.

b = horizontal distance in m (ft.) fromvisor pivot to the centroid of thehorizontal projected area of the visordoor. See Figure 3/20.2.


c = horizontal distance in m (ft.) from thevisor pivot to the center of gravity of thevisor. See Figure 3/20.2.

b Opening Moment The opening moment,Mo, is to be taken as indicated by thefollowing equation:

Mo = Wd + 5Axa kN-m

(Wd + 0.5Axa tf-m, Wd + 0.047Axa Ltf-ft.)

whered = vertical distance, in m (ft.), from the

hinge axis to the center of gravity of thedoor.

W, Ax and a are as indicated above.c Vertical design Force The vertical design

force is to be taken as Fz-W where Fz is asdefined in 3/20.6.6a2 and W is as defined in3/20.6.6a3a.

d Combined Load Case 1 The visor doorsare to be evaluated under a load of Fx, Fz andW acting simultaneously with Fx and Fz

acting at the centroid of their respectiveprojected areas.

e Combined Load Case 2 The visor doorsare to be evaluated under a load of 0.7Fy

acting on each side separately together with0.7Fx, 0.7Fz and W. Fx, Fy and Fz are to betaken as acting at the centroid of theirrespective projected areas.

4 Side-Opening Door Load Casesa Combined Load Case 1 Side opening

doors are to be evaluated under a load of Fx,Fy, Fz and W acting simultaneously with Fx,Fy and Fz acting at the centroid of theirrespective projected areas.

b Combined Load Case 2 Side openingdoors are to be evaluated under a load of0.7Fx, 0.7Fz and W acting on both doorssimultaneously and 0.7Fy acting on eachdoor separately.

b Inner Doors1 External Pressure The design external

pressure is to be taken as the greater of Pei orPh as given by the following equations.

Pei = 0.45L kN/m2 (0.046L1 tf/m2,

0.0042L1 Ltf/ft.2)

Ph = 10h kN/m2 (1.0h tf/m2,0.029h Ltf/ft.2)

whereL is as defined in 3/1.1.h = the distance in m or ft. from the load

point to the top of the cargo space.2 Internal Pressure The design internal

pressure, Pi is to be taken as not less than 25kN/m2 (2.5 tf/m2, 0.23 Ltf/ft2)

3/20.6.7 Allowable Stressesa Primary Structure and Securing and

Supporting Devices The following stresses are notto be exceeded under the loads indicated above.

Shear Stress: τ = 80/Q N/mm2

(8.2/Q kgf/mm2, 11600/Q psi)

Bending Stress: σ = 120/Q N/mm2

(12.2/Q kgf/mm2,17400/Q psi)

Equivalent Stress

s ( σ τ2 23+ ):

σe = 150/Q N/mm2

(15.3/Q kgf/mm2, 18000/Q psi)

where Q is as defined in 3/6.1.1a.

b Steel Securing and Supporting DevicesBearing Stress For steel to steel bearings in securingand supporting devices, the nominal bearing pressureis not to exceed 0.8σf, where σf is the yield stress ofthe bearing material.

c Tensile stress on threaded bolts The tensilestress in threaded bolts is not to exceed 125/Q N/mm2

(12.7/Q kgf/mm2, 18,000/Q psi).

3/20.6.8 Operating and Maintenance ManualThe following information is to be submitted forreview:

a Manual An operating and maintenance manualfor the bow door and inner door is to be provided onboard and is to contain the following:

main particulars and design drawingsservice conditions, e.g. service area

restrictions, acceptable clearances forsupports

maintenance and function testingregister of inspections and repairs

b Operating Procedures Documented operatingprocedures for closing and securing the bow door andinner door are to be kept on board and posted at anappropriate location.

3/20.7 Portlights

3/20.7.1 ConstructionPortlights fitted below the main weather deck or insuperstructure and house side plating are to be ofsubstantial construction and provided with steel,aluminum or other approved material insidedeadlights, permanently attached and arranged to becapable of being closed and secured watertight.Except in way of the machinery space, portlights maybe of the hinged opening type, with hinge pins of non-corrosive material. Where vessels are subject todamaged stability requirements of 3/3.3.2, portlightsfound to be situated below a final damage equilibrium


waterline are to be of the non opening type. Portlightframes are to be of steel or other approved materialand are to be attached to the hull by through bolts orequivalent. Lower edges of portlights are not to bebelow a line parallel to the main weather deck at sidehaving its lowest point at a distance above the designwaterline either 2.5% of the craft breadth or 500 mm(19.5 in.) whichever is greater.

In craft limited in service range and weatherconditions, consideration will be given to theomission of deadlights depending on the type andthickness of the portlight.

The thickness of portlights of tempered ortoughened monolithic safety glass is to be not lessthan given in Table 3/20.1. Consideration will also begiven to laminated glass, acrylic and polycarbonateglazing materials based upon equivalent flexuralstrength and stiffness. See Table 3/20.3 for glazingmechanical properties.

TABLE 3/20.1Thickness of Tempered or Toughened Monolithic

Glass Portlights

a Rounded Portlights

Location General LimitedServiceCraft

Side shell below main weatherdeck

0.050d 0.040d

Superstructure or deckhouse onmain weather deck

0.033d 0.033d

Deckhouses above main weatherdeck

0.025d 0.025d

Notes: d is to be taken as the diameter between inner edgesof the portlight frame in mm or in.For calculation of required thickness on limitedservice craft, d is not to be taken less than 250mm(10in.)

b Rectangular Portlights

Location General LimitedServiceCraft

Side shell below main weatherdeck

0 091. s K 0 0 7 3. s K

Superstructures or deckhouseson main weather deck

0 0 6 0. s K 0 0 6 0. s K

Deckhouses above mainweather deck

0 0 4 5. s K 0 0 4 5. s K

Note: K is to be taken from Table 3/20.2; s is the shortpanel dimension and l is the long windowdimension.

3/20.7.2 TestingAll portlights are to be hose tested after installation.

3/20.8 Windows

3/20.8.1 ConstructionWindows to spaces within enclosed superstructureand deckhouses are to be fitted with strong steel,aluminum or other approved material deadlightcovers. Windows should generally not be fitted in theend bulkheads of superstructures or deckhouses inPosition 1. Window frames are to be of steel or otherapproved material and are to be attached by throughbolts or equivalent.

Windows on the second tier above the freeboarddeck may not require deadlight depending upon thearrangement of the craft. Window frames are to bemetal or other approval material, and effectivelysecured to the adjacent structure. Windows are tohave a minimum of a 1/4” radius at all corners. Theglazing is to be set into the frames in a suitable,approved packing or compound. Specialconsideration to be given to angled house fronts.

The thickness of the window is not to be less thanthat obtained from a, b, or c below, whichever isgreater.

a.

t spk

a

=1000σ

(mm) t spk

a

=σ

(in.)

b.

t spk

E= 13

20 (mm) t s

pk

E= 13

0 02. (in.)

c. Minimum tempered monolithic glassthicknesses:

t = 9.5mm (0.37in.) for front windowst = 6.5mm (0.25in.) for side and endwindows.

t = required window thickness, in mm (in.)s = lesser dimension of window in mm or in.p = pressure head for window location as

determined by 3/8.5k = factor given in Table 3/20.2k1 = factor given in Table 3/20.2σa = 0.30σf

σf = material flexural strength; see Table3/20.3

E = material flexural modulus; see Table3/20.3

3/20.8.2 TestingAll windows are to be hose tested after installation


TABLE 3/20.2

l/s k k1

>5 .750 .142

5 .748 .142

4 .741 .140

3 .713 .134

2 .610 .111

1.8 .569 .102

1.6 .517 .091

1.4 .435 .077

1.2 .376 .062

1 .287 .044

l = greater dimension of window panel, in mmor in.

s = lesser dimension of window panel, in mm orin.

TABLE 3/20.3

Glazing FlexuralStrength

Flexural Modulus

TemperedMonolithic

119 MPa(17,200 psi)

73,000 MPa(10,600,000 psi)

LaminatedGlass

69 Mpa (10,000 psi)

2,620 MPa(380,000 psi)

Polycarbonate* 93 MPa(13,500 psi)

2,345 MPa(340,000 psi)

Acrylic(PMMA) *

110 Mpa (16,000 psi)

3,000 MPa(435,000 psi)

* Indicated values are for reference. Aging effectsare to be considered for design.

3/20.9 Ventilators

3/20.9.1 Coaming ConstructionVentilators on exposed freeboard decks,superstructure decks, or deckhouses are to havecoamings of steel or equivalent material. Coamingplate thicknesses for steel are to be obtained from thefollowing equation:

t = 0.01d + 5.5 mm t = 0.01d + 0.22 in.

t = thickness of coaming in mm or in.d = diameter of ventilator in mm or in. but not

less than 200 mm (7.5in.)

The maximum steel coaming plate thickness requiredis 10 mm (0.40 in.). The coamings are to beeffectively secured to the deck. Coamings which aremore than 900mm (35.5 in.) high and which are notsupported by adjacent structures are to haveadditional strength and attachment. Ventilatorspassing through superstructures other than enclosedsuperstructures are to have substantially constructedcoamings of steel or equivalent material at thefreeboard deck. Coaming plate thickness of materialother than steel will be specially considered.

3/20.9.2 Coaming HeightVentilators in Position 1 are to have coamings at least900 mm (35.5 in.) high. Ventilators in Position 2 areto have coamings at least 760 mm (30 in.) high. Fordefinitions of Position 1 and Position 2, see 3/18.3.Coaming heights may be reduced on craft which havefreeboard in excess of the minimum geometricfreeboard and/or a superstructure deck with height ofdeck in excess of the standard height of asuperstructure.

3/20.9.3 Means for Closing VentilatorsExcept as provided below, ventilator openings are tobe provided with efficient, permanently attachedclosing appliances. In craft measuring 24 m (79 ft) ormore in length (as defined in the InternationalConvention on Load Lines, 1966) ventilators inPosition 1, the coamings of which extend to morethan 4.5 m (14.8 ft) above the deck and in Position 2,the coamings of which extend to more than 2.3 m (7.5ft) above the deck, need not be fitted with closingarrangements.

These coaming height requirements may bemodified in craft measuring less than 24 m (79 ft) inlength.


Figure 3/20.1a

Entry and Flare Angles

Figure 3/20.1b

Definition of ααααm and ββββm


Figure 3/20.2

Visor Type Bow Door

PART 3 SECTION 21|1 Protective Coatings

PART 3 SECTION 21

Protective Coatings

3/21.5 Protection of Steel

3/21.5.1 All SpacesUnless otherwise approved, all steel work is to besuitably coated with paint or equivalent.

3/21.5.2 Salt Water Ballast SpaceTanks or holds for salt water ballast are to have acorrosion-resistant hard type coating such as epoxy orzinc on all structural surfaces. Where a long retentionof salt water is expected due to the type of craft orunit, special consideration for the use of inhibitors orsacrificial anodes may be given.

3/21.5.3 Oil SpacesTanks intended for oil need not be coated.

3/21.6 Protection of Aluminum

3/21.6.1 GeneralAluminum alloys intended for hull construction are tobe used generally only under conditions that will notinduce excessive corrosion. Where exposure toenvironment that would induce excessive corrosion isexpected, suitable coatings, tapes, sacrificial anodes,impressed-current systems or other corrosionprevention measures are to be used. When tapes areused for corrosion protection, they are to be non-wicking and non-water absorbing. Grease containinggraphite is not to be used with aluminum, instead,zinc or other suitable base grease is to be used.

3/21.6.2 CoatingsCoatings are to be applied in accordance with themanufacturer’s instructions, and are to be precededby appropriate cleaning and possibly chemicalconversion of surfaces as may be required inaccordance with the manufacturer’srecommendations. Coatings are to be free fromvoids, scratches or other imperfections that arepotential sites for localized corrosion.

The composition of coatings is to be compatiblewith aluminum. Coatings containing copper, lead,mercury or other metals that can induce galvanic orother forms of corrosion are not to be used. Zincchromate coatings may be used. Insulating coatingsintended to prevent galvanic corrosion are not tocontain graphite or other conducting materials.

3/21.6.3 Faying Surfaces - Aluminum toAluminum

Aluminum faying surfaces that will be exposed toweather, seawater, or other corrosive environment areto be suitable coated to minimize crevice corrosion inway of the faying surfaces.

3/21.6.4 Faying Surface between Aluminum andother Metals

a Hull Suitable means are to be taken to avoiddirect contact of faying surfaces of aluminum to othermetals. When such faying surfaces occur in hullconstruction, suitable non-wicking and non-waterabsorbing insulation tapes or coatings are to be used.Other types of joints between aluminum and othermetals may be approved in certain applications.

b Piping Suitable means, such as special pipehangers, are to be used to avoid conductiveconnections between aluminum hulls and non-aluminum metal piping systems. Wherewatertightness is required, such as when piping passesthrough bulkheads, decks, tanktops, and shell, specialfittings will be required to maintain isolation betweendissimilar metals.

c Bearing Areas Bearing areas such as enginebeds, pump foundations, propeller shafts, rudder andother appendages of metals other than aluminum areto be suitable isolated by such means as non-metallicbearing casing, non-conductive packing (notcontaining graphite or other conductors) or suitabletapes and coatings. Alternative methods forminimizing corrosion at these locations will bespecially considered. Wicking-type tapes or water-absorbing packing materials such as canvas shouldnot be used. The metals used for such applicationsare to be selected to minimize galvanic effects;stainless steels are to be considered. The use ofcopper-base alloys such as brass or bronze isgenerally not recommended where galvanic corrosionis of concern, and these materials may only be usedwhen specially approved. In those cases where theuse of dissimilar metals cannot be avoided, or wheregalvanic corrosion is of concern, such as in wet tanks,a suitable sacrificial anode or impressed currentsystem should be installed.

PART 3 SECTION 21|2 Protective Coatings

3/21.6.5 Faying Surface between Aluminum andNon-metals

Aluminum in contact with wood or insulating-typematerial is to be protected from the corrosive effectsof the impurities in these materials by a suitablecoating or covering. Concrete used with aluminum isto be free of additives for cold weather pouring.Preformed glass insulation is recommended forpiping insulation. Any adhesives which may be usedto connect insulation to aluminum are to be free ofagents that would be corrosive to aluminum.Foaming agents harmful to aluminum, such as freon,are not to be used for insulating foams. Areas wheredirt or soot are likely to collect and remain forprolonged periods are to be protected from pittingcorrosion by the use of coatings or other suitablemeans.

3/21.6.6 Corrosion of Wet SpacesSuitable means are to be used to avoid arrangementsthat could induce crevice corrosion in wet spaces. Inbilge spaces, chain lockers, and similar locationswhere exfoliation corrosion may be of concern,appropriate materials suitably heat treated forresistance to this form of corrosion are to beemployed.

3/21.6.7 Service at Elevated TemperaturesFor service temperatures of 66°C (150°F) or above,only aluminum alloys and filler metals speciallydesignated for service at these temperatures are to beused.

3/21.6.8 Cathodic Protection for CorrosionPrevention

For application where corrosion is of concern,consideration is to be given to the use of sacrificialanode or impressed current systems of corrosioncontrol. Details of sacrificial anodes andarrangements are to be submitted for review. Anodesare to be in accordance with ASTM or otherrecognized standard. When impressed currentsystems are used, adequate precautions are to betaken that the negative voltage is not excessive.

3/21.6.9 Stray Current ProtectionPrecautions are to be taken when in dock to preventstray currents from welding power or other sourcesfrom adversely affecting the aluminum. Wheneverpossible, the cathodic protection system of the craftshould be in place and operating when the craft is inthe water. A.C. power sources are to be insulatedfrom the hull. For battery and other D.C. powersources, grounding is to be avoided if possible.Where safety considerations require grounding to thehull, the negative pole is to be connected to the hull.

3/21.6.10 Bi-material JointsSuch joints, when used, may be required to beappropriately painted, coated, wrapped or protectedby other methods to prevent galvanic corrosion.Where aluminum is to be joined to other materials,each faying surface is to be suitably coated tominimize corrosion. In addition, when one or bothsides of an aluminum or steel connection to dissimilarmetal joints are exposed to weather, sea water, or wetspaces, a minimum of 0.5mm (0.02 in.) of suitableinsulation is to be installed between faying surfacesand extended beyond the edge of the joint. Non-welded oil or water stops are to be of plasticinsulation tape or equivalent which would provide asuitably corrosion resistant system.

3/21.8 Protection of Fiber Reinforced Plastic

3/21.8.1 GeneralCured gel-coat resins and lay-up resin are to be highlyresistant to water and other liquid absorption;appropriate materials, lay-up, and lay-up proceduresare to be used and manufacturer’s recommendationsfollowed to attain this. Care is to be taken in the useof laminates containing carbon fibers so that they arenot close to or do not induce galvanic corrosion withmetal fittings.

3/21.8.2 TanksIn water, fuel oil, or other approved tanks, the resinsused are to be compatible with the contents of thetanks; the contents of the tanks are not to affect thecured properties of the tank laminate. The curedlaminate is to be highly resistant to absorption of theliquid, and is not to have harmful, deleterious, orundesirable effects on the contents of the tank. Thetank is generally to be gel-coated on the inside. Seealso 3/12.3.1.

3/21.8.3 Cathodic ProtectionCathodic protection is to be provided where shaftstruts, propeller shafts, propellers, rudders, fittings,etc. are constructed of manganese bronze, brass,stainless steel or mild steel. Details of the sacrificialanodes and arrangements are to be submitted forreview. Anodes are to be in accordance with ASTMor other recognized standard.

PART 3 SECTION 22|1 Equipment

PART 3 SECTION 22

Equipment3/22.1 General

All craft are to have a complete equipment of anchors

and chains. The letter placed after the symbols of

classification in the Record, thus: !!!!A1 , willsignify that the equipment of the craft is incompliance with the requirements of the Guide, orwith requirements corresponding with the servicelimitation noted in the craft’s classification, whichhave been specially approved for the particularservice.

Cables which are intended to form part of theequipment are not to be used as deck chains when thecraft is launched. The inboard ends of the cables ofthe bower anchors are to be secured by efficientmeans. Anchors and their cables are to be connectedand positioned, ready for use. Where three anchorsare given in Table 3/22.1, the third anchor is intendedas a spare bower anchor and is listed for guidanceonly; it is not required as a condition of classification.Means are to be provided for stopping each cable as itis paid out, and the windlass should be capable ofheaving in either cable. Suitable arrangements are tobe provided for securing the anchors and stowing thecables.

3/22.3 Calculation of EN

3/22.3.1 Monohullsa Basic Equation The basic Equipment Number

(EN) is to be obtained from the following equationfor use in determining required equipment.

EN = + +k mBh nA∆2 3

k = 1.0 (1.0, 1.012)m = 2 (2, 0.186)n = 0.1 (0.1, 0.00929)∆ = molded displacement in metric tons (long

tons) at the summer load waterline.B = molded breadth as defined in 3/1.3 in m or fth = a + h1 + h2 + h3 + . . . as shown in Figure

3/22.1. In the calculation of h, sheer, camberand trim may be neglected.

a = freeboard, in m (ft), from the summer loadwaterline amidships.

h1, h2, h3...= height in m (ft), on the centerline ofeach tier of houses having a breadth greaterthan B/4.

A = profile area in m2 (ft2) of the hull,superstructure and houses above the summer

load waterline which are within L (see 3/1.1).Superstructures or deckhouses having abreadth at any point no greater than 0.25Bmay be excluded. Screens and bulwarks morethan 1.5 m (4.9 ft) in height are to be regardedas parts of houses when calculating h and A.

b Craft of Unrestricted Ocean Service HavingEN of 205 and Above For craft of unrestricted oceanservice having an EN of 205 or above in accordancewith 3/22.3.1, the calculated EN is to be used inassociation with Table 3/22.1.

c Craft having EN less than 205 For craft ofunrestricted ocean service having a basic EN less than205 calculated in accordance with 3/22.3.1a, the ENfor use with Table 3/22.1 may be calculated inaccordance with the following equation.

Equipment Number ( )= + + +∑k m Ba bh nA∆2 3

Where k, m, n, ∆, B, a and A are as defined in3/22.3.1a above and;

b = breadth in m or ft of the widest superstructureor deckhouse on each tier.

h = the height in m or ft of each tier of deckhouseor superstructure having a width of B/4 orgreater. In the calculation of h, sheer, camberand trim may be neglected. See Figure 3/22.1.

3/22.3.2 Multi-Hulled CraftAnchors and chains are to be not less than given inTable 3/22.1 and the numbers, weights and sizes ofthese are to be based on the equipment numberobtained from the following equation. Specialconsideration will be given where anchoring andmooring conditions are specified.

EN = [ ] [ ]( ) nAhaBBamk ++++∆ ∑113/2 2

k, ∆, m, n and A are as defined in 3/22.3.1. B, B1, a,a1, h1, h2, h3, Σh are shown in Figure 3/22.1b


FIGURE 3/22.1 - Effective Heights of Deckhousesa Monohulls

b Multi-Hulled Craft


3/22.5 Craft of Unrestricted Service

The equipment, weight and size of all craft inunrestricted service is to be in accordance with Table3/22.1 in association with the EN calculated in 3/22.3

3/22.7 Restricted Service CraftCraft intended for restricted service (see 1/1.3.4) andhaving their own moorage are to have one anchor ofthe tabular weight and one-half the tabulated length ofanchor chain in Table 3/22.1. Alternatively, twoanchors of one-half the tabular weight with the totallength of anchor chain listed in Table 3/22.1 may befitted provided both anchors are positioned and readyfor use and the windlass is capable of heaving ineither anchor. These craft are to have adequatetowing arrangements so that the craft can be towed inthe worst intended conditions. In the areas of thetowing arrangements where the towing cable issusceptible to chafing there is to be sufficient radiusto prevent the cable from being damaged when underload.

3/22.9 Materials and Tests

Material and testing for anchors and chains on craftare to be in accordance with the requirements of 2/1for the respective sizes of anchors and chains. See2/1.11 through 2/1.13. Materials and tests for wirerope are to be in accordance with a national or otherrecognized standard.

3/22.11 Anchor Types

3/22.11.1 GeneralAnchors are in general to be of the stockless type.The weight of the head of a stockless anchor,including pins and fittings, is not to be less than three-fifths of the total weight of the anchor.

3/22.11.2 High Holding Power Anchors (HHP)Where the anchor has a proven holding power of notless than two times that of an ordinary stocklessanchor and has been tested in accordance with 2/1.11a weight reduction of 25% from the weight specifiedin Table 3/22.1 will be given. For HHP anchors anappropriate notation will be made in the Record.

3/22.11.3 Super High Holding Power Anchors(SHHP)

Where the anchor has a proven holding power of notless than four times that of an ordinary stocklessanchor and has been tested in accordance with 2/1.11a weight reduction of 50% from the weight specifiedin Table 3/22.1 will be given. For SHHP anchors anappropriate notation will be made in the Record.

3/22.13 Windlass or Winch

3/22.13.1 GeneralThe windlass is to be of good and substantial makesuitable for the size of intended anchor cable. Thewinch is to be well bolted down to a substantial bed,and deck beams below the windlass are to be of extrastrength and additionally supported. Where wireropes are used in lieu of chain cables, winchescapable of controlling the wire rope at all times are tobe fitted.

Construction and installation of all windlasses andwinches used for anchoring are to be carried out inaccordance with the following requirements, to thesatisfaction of the Surveyor. In general, the design isto conform to an applicable standard or code ofpractice. As a minimum, standards or practices are toindicate strength, performance and testing criteria.

The manufacturer or builder is to submit inaccordance with 4/1.11, the following, as applicable:

a Plans1 Arrangement and details of the windlass or

winch, drums, brakes, shaft, gears,coupling bolts, wildcat, sheaves, pulleysand foundation.

2 Electric one line diagram.3 Piping system diagrams.4 Control arrangements.

Plans or data are to show complete details includingpower ratings, working pressures, welding details,material specifications, pipe and electric cablespecifications, etc.

b Calculations Detailed stress calculations forthe applicable system components listed in a1 above.The calculations are to be based on the breakingstrength of the chain or wire rope; are to indicatemaximum torque or load to which the unit will besubjected and also show compliance with eitherapplicable sections of the Rules such as 4/3.29 of theRules for Building and Classing Steel Vessels for thegears and shafts, or to other recognized standard orcode of practice.

3/22.13.2 Support StructureThe windlass or winch is to be well bolted down to asubstantial foundation. The stresses in the structuressupporting the windlass are not to be exceed the yieldpoint of the material under the following load appliedin the direction of the chain:

With cable stopper: 45% of B.S.Without cable stopper: 80% of B.S.

B.S. = minimum breaking strength of the chain asindicated in Tables 2/1.9 and 2/1.10.


An independent cable stopper and its components areto be adequate for the load imposed. Thearrangements and details of the cable stopper are tobe submitted for review.

3/22.15 Trial

See 1/2.3

3/22.17 Hawse Pipes

Hawse pipes are to be of ample size and strength;they are to have full rounded flanges and the leastpossible lead, in order to minimize the nip on thecables; they are to be securely attached to thickdoubling or insert plates by continuous welds the sizeof which are to be in accordance with Section 3/23for the plating thickness and type of joint selected.When in position they are to be thoroughly tested forwatertightness by means of a hose in which the waterpressure is not to be less than 2.06 bar (2.1 kgf/cm2,30 psi). Hawse pipes for stockless anchors are toprovide ample clearances; the anchors are to beshipped and unshipped so that the Surveyor may besatisfied that there is no risk of the anchor jamming inthe hawse pipe. Care is to be taken to ensure a fairlead for the chain from the windlass to the hawsepipes and to the chain pipes.


TABLE 3/22.1Equipment for Self-propelled Ocean-going CraftSI, Metric Units

The weight per anchor of bower anchors given in Table 3/22.1 is for anchors of equal weight. The weight ofindividual anchors may vary 7% plus or minus from the tabular weight provided that the combined weight of allanchors is not less than that required for anchors of equal weight. The total length of chain required to be carried onboard, as given in Table 3/22.1, is to be reasonably divided between the two bower anchors. Where three anchorsare given in Table 3/22.1, the third anchor is intended as a spare bower anchor and is listed for guidance only; it isnot required as a condition of classification.

Stockless BowerAnchors

Chain Cable Stud Link Bower Chain

DiameterEquipmentNumeral

EquipmentNumber*

Number Mass perAnchor,

kg

Length, m Normal-StrengthSteel (Grade 1),

mm

High-StrengthSteel (Grade 2),

mm

Extra High-Strength Steel(Grade 3), mm

UA1 30 2 75 192.5 12.5 - -UA2 40 2 100 192.5 12.5 - -UA3 50 2 120 192.5 12.5 - -UA4 60 2 140 192.5 12.5 - -UA5 70 2 160 220 14 12.5 -

UA6 80 2 180 220 14 12.5 -UA7 90 2 210 220 16 14 -UA8 100 2 240 220 16 14 -UA9 110 2 270 247.5 17.5 16 -

UA10 120 2 300 247.5 17.5 16 -

UA11 130 2 340 275 19 16 -UA12 140 2 390 275 20.5 17.5 -

U6 150 2 480 275 22 19 -U7 175 2 570 302.5 24 20.5 -U8 205 3 660 302.5 26 22 20.5U9 240 3 780 330 28 24 22

U10 280 3 900 357.5 30 26 24

U11 320 3 1020 357.5 32 28 24U12 360 3 1140 385 34 30 26U13 400 3 1290 385 36 32 28U14 450 3 1440 412.5 38 34 30U15 500 3 1590 412.5 40 34 30

U16 550 3 1740 440 42 36 32U17 600 3 1920 440 44 38 34U18 660 3 2100 440 46 40 36U19 720 3 2280 467.5 48 42 36U20 780 3 2460 467.5 50 44 38

U21 840 3 2640 467.5 52 46 40U22 910 3 2850 495 54 48 42U23 980 3 3060 495 56 50 44U24 1060 3 3300 495 58 50 46U25 1140 3 3540 522.5 60 52 46

U26 1220 3 3780 522.5 62 54 48U27 1300 3 4050 522.5 64 56 50U28 1390 3 4320 550 66 58 50U29 1480 3 4590 550 68 60 52U30 1570 3 4890 550 70 62 54


TABLE 3/22.1 (Continued)SI, Metric Units


Chain Cable Stud Link Bower Chain**


EquipmentNumber*

Number Mass perAnchor,

kg

Length, m Normal-StrengthSteel (Grade 1),

mm


mm

Extra High-Strength Steel(Grade 3), mm

U31 1670 3 5250 577.5 73 64 56U32 1790 3 5610 577.5 76 66 58U33 1930 3 6000 577.5 78 68 60U34 2080 3 6450 605 81 70 62U35 2230 3 6900 605 84 73 64

U36 2380 3 7350 605 87 76 66U37 2530 3 7800 632.5 90 78 68U38 2700 3 8300 632.5 92 8.1 70U39 2870 3 8700 632.5 95 84 73U40 3040 3 9300 660 97 84 76

U41 3210 3 9900 660 100 87 78U42 3400 3 10500 660 102 90 78U43 3600 3 11100 687.5 105 92 81U44 3800 3 11700 687.5 107 95 84U45 4000 3 12300 687.5 111 97 87

U46 4200 3 12900 715 114 100 87U47 4400 3 13500 715 117 102 90U48 4600 3 14100 715 120 105 92U49 4800 3 14700 742.5 122 107 95U50 5000 3 15400 742.5 124 111 97

U51 5200 3 16100 742.5 127 111 97U52 5500 3 16900 742.5 130 114 100U53 5800 3 17800 742.5 132 117 102U54 6100 3 18800 742.5 120 107U55 6500 3 20000 770 124 111

U56 6900 3 21500 770 127 114U57 7400 3 23000 770 132 117U58 7900 3 24500 770 137 122U59 8400 3 26000 770 142 127U60 8900 3 27500 770 147 132U61 9400 3 29000 770 152 132

U62 10000 3 31000 770 137U63 10700 3 33000 770 142U64 11500 3 35500 770 147U65 12400 3 38500 770 152U66 13400 3 42000 770 157U67 14600 3 46000 770 162

* For intermediate values of equipment number use equipment complement in sizes and weights given for the lower equipment number in thetable.

** Wire ropes may be used in lieu of chain cables for both anchors on craft having an Equipment Number less than 150.The wire is to have a breaking strength not less than the grade 1 chain of required size and a length of at least 1.5 times the chain it is

replacing.Between the wire rope and anchor, chain cable of the required size having a length of 12.5 m (41.0 ft), or the distance between anchor

in stored position and winch, whichever is less, is to be fitted.For craft having a very small Equipment Number, nylon rope may be specially considered.


TABLE 3/22.1Equipment for Self-propelled Ocean-going CraftUS Units

The weight per anchor of bower anchors given in Table 3/22.1 is for anchors of equal weight. The weight ofindividual anchors may vary 7% plus or minus from the tabular weight provided that the combined weight of allanchors is not less than that required for anchors of equal weight. The total length of chain required to be carried onboard, as given in Table 3/22.1, is to be reasonably divided between the two bower anchors. Where three anchorsare given in Table 3/22.1, the third anchor is intended as a spare bower anchor and is listed for guidance only; it isnot required as a condition of classification.


Chain Cable Stud Link Bower Chain**


EquipmentNumber*

Number Massper

Anchor,pounds

Length, fathoms Normal-StrengthSteel (Grade 1),

inches


inches

Extra High-Strength Steel

(Grade 3),inches

UA1 30 2 165 105 1/2 - -UA2 40 2 220 105 1/2 - -UA3 50 2 265 105 1/2 - -UA4 60 2 310 105 1/2 - -UA5 70 2 350 120 9/16 1/2 -

UA6 80 2 400 120 9/16 1/2 -UA7 90 2 460 120 5/8 9/16 -UA8 100 2 530 120 5/8 9/16 -UA9 110 2 595 135 11/16 5/8 -

UA10 120 2 670 135 11/16 5/8 -

UA11 130 2 750 150 3/4 11/16 -UA12 140 2 860 150 13/16 11/16 -

U6 150 2 1060 150 7/8 3/4 -U7 175 2 1255 165 15/16 13/16 -U8 205 3 1455 165 1 7/8 13/16U9 240 3 1720 180 1 1/8 15/16 7/8

U10 280 3 1985 195 1 3/16 1 15/16

U11 320 3 2250 195 1 1/4 1 1/8 15/16U12 360 3 2510 210 1 5/16 1 3/16 1U13 400 3 2840 210 1 7/16 1 1/4 1 1/8U14 450 3 3170 225 1 1/2 1 5/16 1 3/16U15 500 3 3500 225 1 9/16 1 5/16 1 3/16

U16 550 3 3830 240 1 5/8 1 7/16 1 1/4U17 600 3 4230 240 1 3/4 1 1/2 1 5/16U18 660 3 4630 240 1 13/16 1 9/16 1 7/16U19 720 3 5020 255 1 7/8 1 5/8 1 7/16U20 780 3 5420 255 2 1 3/4 1 1/2

U21 840 3 5820 255 2 1/16 1 13/16 1 9/16U22 910 3 6280 270 2 1/8 1 7/8 1 5/8U23 980 3 6740 270 2 3/16 1 15/16 1 3/4U24 1060 3 7270 270 2 5/16 2 1 13/16U25 1140 3 7800 285 2 3/8 2 1/16 1 13/16

U26 1220 3 8330 285 2 7/16 2 1/8 1 7/8U27 1300 3 8930 285 2 1/2 2 3/16 2U28 1390 3 9520 300 2 5/8 2 5/16 2U29 1480 3 10120 300 2 11/16 2 3/8 2 1/16U30 1570 3 10800 300 2 3/4 2 7/16 2 1/8


TABLE 3/22.1 (Continued)US Units


Chain Cable Stud Link Bower Chain


EquipmentNumber*

Number Massper

Anchor,pounds

Length, fathoms Normal-StrengthSteel (Grade 1),

inches


inches

Extra High-Strength Steel

(Grade 3),inches

U31 1670 3 11600 315 2 7/8 2 1/2 2 3/16U32 1790 3 12400 315 3 2 5/8 2 5/16U33 1930 3 13200 315 3 1/16 2 11/16 2 3/8U34 2080 3 14200 330 3 3/16 2 3/4 2 7/16U35 2230 3 15200 330 3 5/16 2 7/8 2 1/2

U36 2380 3 16200 330 3 7/16 3 2 5/8U37 2530 3 17200 345 3 9/16 3 1/16 2 11/16U38 2700 3 18300 345 3 5/8 3 3/16 2 3/4U39 2870 3 19200 345 3 3/4 3 5/16 2 7/8U40 3040 3 70500 360 3 7/8 3 5/16 3

U41 3210 3 21800 360 3 15/16 3 7/16 3 1/16U42 3400 3 23100 360 4 3 9/16 3 1/16U43 3600 3 24500 375 4 1/8 3 5/8 3 3/16U44 3800 3 25800 375 4 1/4 3 3/4 3 5/16U45 4000 3 27100 375 4 3/8 3 7/8 3 7/16

U46 4200 3 28400 390 4 1/2 3 15/16 3 7/16U47 4400 3 29800 390 4 5/8 4 3 9/16U48 4600 3 31100 390 4 3/4 4 1/8 3 5/8U49 4800 3 32400 405 4 3/4 4 1/4 3 3/4U50 5000 3 33900 405 4 7/8 4 3/8 3 7/8

U51 5200 3 35500 405 5 4 3/8 3 7/8U52 5500 3 37200 405 5 1/8 4 1/2 3 15/16U53 5800 3 39200 405 5 1/8 4 5/8 4U54 6100 3 41400 405 4 3/4 4 1/4U55 6500 3 44000 420 4 7/8 4 3/8

U56 6900 3 47400 420 5 4 1/2U57 7400 3 50700 420 5 1/8 4 5/8U58 7900 3 54000 420 5 3/8 4 3/4U59 8400 3 57300 420 5 5/8 5U60 8900 3 60600 420 5 3/4 5 1/8U61 9400 3 63900 420 6 5 1/8

U62 10000 3 68000 420 5 3/8U63 10700 3 72500 420 5 5/8U64 11500 3 78000 420 5 3/4U65 12400 3 85000 420 6U66 13400 3 92500 420 6 1/8U67 14600 3 101500 420 6 3/8

* For intermediate values of equipment number use equipment complement in sizes and weights given for the lower equipment number in thetable.

** Wire ropes may be used in lieu of chain cables for both anchors on craft having an Equipment Number less than 150.The wire is to have a breaking strength not less than the grade 1 chain of required size and a length of at least 1.5 times the chain it is

replacing.Between the wire rope and anchor, chain cable of the required size having a length of 12.5 m (41.0 ft), or the distance between anchor

in stored position and winch, whichever is less, is to be fitted.For craft having very small Equipment Numbers, nylon rope may be specially considered.

PART 3 SECTION 23|1 Welding, Forming and Weld Design

PART 3 SECTION 23

Welding, Forming, and Weld Design

3/23.1 Fillet Welds

3/23.1.1 GeneralFillet welds may be made by an approved manual,semi automatic or automatic process. The sizes offillet welds are subject to approval in each case, andare to be indicated on detail drawings or on a separatewelding schedule. When terminating an aluminumweld, either continuous or intermittent, crater fillingby back stepping is recommended to provide a soundending for each fillet.

3/23.1.2 Tee ConnectionsIn general, the required size and spacing of the filletsis to be as given in 3/23.1.3. Special considerationwill be given where there is a substantial differencebetween the thickness of members being connected.Where the opening between members exceeds 1.0mm (0.04 in.) and is not greater than 5mm (0.1875in.), the size of the fillets is to be increased by theamount of the opening. Spacing between platesforming tee joints is not to exceed 5 mm (0.1875 in.).

3/23.1.3 Fillet Sizes and SpacingTee connections are to be formed by continuous orintermittent fillet welds on each side, the leg size, w,of the fillet welds is to be obtained from the followingequations:

w t Cs

lp= × × +15. mm

w t Cs

lp= × × +0 06. in

w = the size of the weld leg in mm or in.l = the actual length of the weld fillet, clear of

crater, in mm or in. See Figure 3/23.1.s = the distance between centers of weld fillets,

in mm or in. See Figure 3/23.1.tp = thickness of the thinner of the two members

being joined in mm or in.C = weld factor given in Table 3/23.1.

w is not to be taken less than 0.3tp or 3.5 mm(0.14in.), whichever is greater.

The throat thickness of the fillet is to be not lessthan 0.7w.

In calculating weld factors, the leg length ofmatched fillet weld is to be taken as the designated

leg length or 0.7tp + 2.0mm (0.7tp + 0.08 in.)whichever is less.

Where it is intended to use continuous filletwelding, the leg size of fillet welds is to be obtainedfrom the above equations taking s/l equal to 1.

For intermittent welding with plate thickness lessthan 7 mm (0.28 in.) welds are to be staggered.

3/23.1.4 Fillet Weld Arrangementsa Intersections Where beams, stiffeners, frames,

etc, are intermittently welded and pass through slottedgirders, shelves or stringers, there is to be a pair ofmatched 75mm (3 in.) intermittent welds on each sideof each such intersection and the beams, stiffenersand frames are to be efficiently attached to thegirders, shelves and stringers.

b Unbracketed End Attachments Unbracketedbeams, frames, etc. and stiffeners of watertight andtank bulkheads and superstructure and house frontsare to have double continuous welds for length ateach end equal to the depth of the member but notless than 75mm (3 in.).

c Bracketed End Attachments Frames, beams,stiffeners etc. are to be lapped onto the bracket alength not less than 1.5 times the depth of themember, and are to have continuous fillet welds allaround. Lapped end connections of longitudinalstrength members are also to have a throat size, t,such that the total effective area of the lap welding isnot less than the area of the member being attached.

d Lapped Joints Lapped joints are generally tohave a width of overlap not less than twice thethickness of thinner plate plus 25 mm (1 in.) withwelds on both edges of the sizes required by 3/23.1.3.

e Plug Welds or Slot Welds Plug welds or slotwelds are to be specially approved for particularapplications. When approved, an appropriatedemonstration that adequate weld penetration andsoundness is achieved is to be made to the Surveyor’ssatisfaction. When used in the attachment of doublersand similar applications, plug or slot welds may bespaced at 16 times the doubler thickness, but notmore than 300 mm (12 in.) between centers in bothdirections. In general, elongated slot welds arerecommended. For closing plates on rudders, slotsare to be 75mm (3 in.) in length spaced at 150 mm (6in.) between centers. The periphery of the plugs orslots are to be fillet welded, of fillet size, w, generallynot less than 0.70 times the plate thickness. Plugsand slots are not to be filled with welded deposit.


3/23.3 Bi-material JointsTechniques required for joining two differentmaterials will be subject to special consideration.The use of explosion bonding may be considereddepending on the application and the mechanical andcorrosive properties of the joint.

3/23.7 AlternativesThe foregoing are considered minimum requirementsfor welding in hull construction, but alternativemethods, arrangements and details will be consideredfor approval.

FIGURE 3/23.1


TABLE 3/23.1Weld Factor C

Aluminum SteelFloors, Bottom Transverses, and Bottom Girders to Shell

At Bottom forward 3L/8, V> 25 knots 0.25 0.25At Bottom forward L/4, V<= 25 knots 0.18 0.16In way of propellers and shaft struts 0.25 0.25 DCIn machinery space 0.20 0.20Elsewhere 0.16 0.14

Floors, Bottom Transverses and Bottom Girders to Inner Bottom or Face BarIn machinery space 0.25 DC 0.25 DCTo Inner bottom elsewhere 0.14 0.12To face plate elsewhere 0.14 0.12

Floors and Bottom Transverse to Bottom Girders 0.30 DC 0.30 DCBottom Girders to Bulkheads and Deep Transverses or Floors 0.30 DC 0.30 DCEnd Attachments - single bottom construction 0.50 DC 0.50 DCFrames to Shell

At Bottom forward 3L/8, V>25 knots 0.25 DC 0.25 DCAt Bottom forward L/4, V<=25 knots 0.18 0.16In way of propellers and shaft struts 0.25 DC 0.25 DCElsewhere 0.14 0.12End Attachments 0.50 DC 0.50 DC

Girders, Transverses and StringersTo Shell (transverse) 0.16 0.14To Deck and Bulkheads Clear of Tanks 0.16 0.14To Deck and Bulkheads In way of Tanks 0.18 0.16To Face Bar 0.14 0.12End Attachments 0.50 DC 0.50 DC

Beams and StiffenersTo Deck 0.14 0.12To Tank Boundaries and House Fronts 0.14 0.12To Watertight Bulkheads, House Side and Ends 0.14 0.12End Attachments 0.50 DC 0.50 DC

Engine Foundations to Plating and Face Bar 0.50 DC 0.50 DCBulkheads and Tank Boundaries

Non-Tight, Internal 0.16 0.14Weathertight, or exposed 0.38 DC 0.38 DCTank 0.40 DC 0.40 DC

DecksNon-tight, Internal 0.25 0.25Weathertight 0.38 DC1 0.38 DC1

Strength Deck 0.38 DC1 0.38 DC1

RuddersDiaphragms to Side Plating 0.30 0.30Vertical Diaphragms to Horizontal Diaphragms, clear of Mainpiece 0.50 DC 0.50 DCHorizontal Diaphragm to Vertical 0.50DC 0.50 DCMainpiece Diaphragm 0.50 DC 0.50DC

Shaft Brackets to boss and doubler Full Penetration Full PenetrationNotes: DC = double continuous

1 = Where plate thickness is less than 12.5mm (0.50 in.), upper weld to be continuous, lower weld maybe intermittent as required by welding beams or stiffeners to tank boundaries.

PART 3 SECTION 24|1 Fire Safety Measures

PART 3 SECTION 24

Fire Safety

3/24.1 General

3/24.1.1 SOLAS ApplicationFor classification purposes, the fire and safetymeasures contained in the International Conventionfor the Safety of Life at Sea, 1974 (1974 SOLAS) asamended, are applicable to crafts of type, size andservice coming under that Convention. This includesthe IMO International Code of Safety for High SpeedCraft (HSC Code).

This section does not relax the requirements inother sections of the Rules.

Gross tonnage is to be taken as defined in 3/1.19.

3/24.1.2 RegulationRegulation means the regulation contained in 1974SOLAS as amended. An abbreviated notation isused, e.g. Regulation II-2/4.2 means Regulation 4.2of Chapter II-2.

3/24.3 Passenger CraftFor passenger craft as defined in 1.1 through 1.4 ofthe HSC Code, the requirements in 7.1 through7.6HSC Code are applicable. See also Section 5/1 ofthis Guide.

For all passenger craft subject to 1974 SOLAS asamended, the requirements in Part B (Regulations 23through 41) Chapter II-2 are applicable. See alsoSection 5/5 of the Rules for Building and ClassingSteel Vessels.

3/24.5 Cargo CraftFor cargo craft as defined in 1.1 through 1.4 of theHSC Code, the requirements in 7.1 through 7.6 HSCCode are applicable.

For all cargo craft subject to 1974 SOLAS asamended, the requirements in Part C (Regulations 42through 54) Chapter II-2 are applicable.

3/24.7 Review Procedures

3/24.7.1 Administration ReviewWhen the craft is issued a Passenger Ship SafetyCertificate, Cargo Ship Safety Equipment Certificate,Cargo Ship Safety Construction Certificate, or HighSpeed Craft Safety Construction Certificate by theflag Administration or its agent other than the Bureau,such Certificate will be accepted as evidence that the

craft is in accordance with the applicable criteria in1974 SOLAS as amended.

Where the Administration undertakes any part ofthe review and the Bureau is issuing aboveCertificate, the acceptance by the Administration willbe required before the certificate is issued.

Compliance with the Rule requirements inaddition to those in 1974 SOLAS as amended is to beverified by the Bureau.

3/24.7.2 Bureau ReviewIn all other cases, the required information and plansare to be submitted to the Bureau for review.

3/24.9 The Review of Craft Constructed of FiberReinforced Plastic (FRP)

FRP fire-restricting divisions may be consideredprovided they meet the required tests for fire-restricting materials and fire-resisting divisions, orcomply with an acceptable fire risk assessment. FRPdivisions may also be considered on the basis oflocation with regard to diminished fire risk andenhanced fire detection/extinguishing means.

PART 3 APPENDIX 3/A|1 Guidelines in Calculating Bending Moment and Shear Force in Rudders andRudder Stocks

PART 3 APPENDIX 3/A

Guidelines in Calculating Bending Momentand Shear Force in Rudders and RudderStocksBending moments, shear forces and reaction forces of rudders, stocks and bearings may be calculated according tothis Appendix for the types of rudders indicated. Moments and forces on rudders of different types or shapes thanthose shown are to be calculated using alternative methods and will be specially considered.

3/A.1 Spade Rudders

3/A.1.1 Ruddera Shear Force Lateral shear force at a horizontal

section of the rudder z meters (feet) above the bottomof lR is given by the following equation.

V zzC

Ac

z

lc cR

lR

u l( ) ( )= + −

2

kN (tf, Ltf)

V(z) = lateral shear force at the section of therudder under consideration.

z = distance from the bottom of lR to thehorizontal section under consideration in m(ft)

CR = rudder force as defined in 3/5.2.1 in kN (tf,Ltf)

A = rudder blade area in m2 (ft2)cl, cu, and lR are dimensions as indicated in Figure

3/A.1 in m (ft).

b Bending moment Bending at a horizontalsection z meters (feet) above the baseline of therudder is given by the following equation.

M zz C

Ac

z

lc cR

lR

u l( ) ( )= + −

2

2 3kN-m (tf-m,

Ltf-ft)

M(z) = bending moment at the horizontal section ofthe rudder under consideration.

z, CR, A, cl, cu and lR are as defined in 3/A.1.1a.

3/A.1.2 Lower Stocka Shear Force Lateral shear force at any section

of the lower stock between the top of the rudder andthe neck bearing is given by the following equation.

V Cl R= kN (tf, Ltf)

Vl = transverse shear force in the lower stock.CR = rudder force as defined in 3/A.1.1a

b Bending Moment at Neck Bearing Thebending moment in the rudder stock at the neckbearing is given by the following equation.

M C ll c c

c cn R lR u

l u

= ++

+

( )

( )

2

31 kN-m (tf-m, Ltf-ft)

Mn = bending moment at the neck bearing of therudder stock.

CR = rudder force as defined in 3/A.1.1acl, cu, ll and lR are dimensions as indicated in Figure

3/A.1 in m (ft).

3/A.1.3 Moment at Top of Upper Stock TaperThe bending moment in the upper rudder stock at thetop of the taper is given by the following equation.

M C ll c c

c c

l l l z

lt R lR l u

l u

u R l t

u

= ++

+

×

+ + −

( )

( )

2

3 kN-m (tf-m, Ltf-f)

Mt = bending moment at the top of the upperrudder stock taper.

zt = distance from the rudder baseline to the topof the upper rudder stock taper in m (ft)

CR = rudder force as defined in 3/A.1.1a

PART 3 APPENDIX 3/A|2 Guidelines in Calculating Bending Moment and Shear Force in Rudders andRudder Stocks

cl, cu, ll, lu and lR are dimensions as indicated inFigure 3/A.1 in m (ft).

3/A.1.4 Bearing Reaction ForcesReaction forces at the bearings are given by thefollowing equations.

PM

lun

u

= − kN (tf, Ltf)

P CM

ln Rn

u

= + kN (tf, Ltf)

Pu = reaction force at the upper bearing.Pn = reaction force at the neck bearing.Mn = bending moment at the neck bearing as

defined in 3/A.1.1bCR = rudder force as defined in 3/A.1.1alu is as indicated in Figure 3/A.1 in m (ft).

FIGURE 3/A.1Spade Rudder

PART 3 APPENDIX 3/B|1 Guidance on Torsional Analysis of the Cross Deck Structure of a Multi-Hull Craft

PART 3 APPENDIX 3/B

Guidance on Torsional Analysis of theCross Deck Structure of a Multi-Hull Craft

This appendix gives guidance on the torsional analysis of a standard cross deck structure (constructed of aluminumor steel similar to Figure 3/B.1) of a multi-hulled craft. The torsional analysis includes the determination of thecraft’s torsional moment of inertia and section modulus, and the maximum stress that is acting on each element. Thetorsional analysis of cross decks that are of advanced design or material other than steel or aluminum will bespecially considered.

FIGURE 3/B.1Typical Geometry of Centerline Section of Cross Deck

3/B.1 Torsional Moment of Inertia

The offered torsional moment of inertia of the crossdeck structure can be determined by the followingformula:

J k L k xt ii

n

c i ii

n

= − × += =∑ ∑( ) ( )

1

2 2

1

Jt = torsional moment of inertia.

ki = element stiffness, 3

12

i

i

L

EI

xi = longitudinal distance from forwardperpendicular in cm or in.

n = total number of elements in the cross deckstructure.

Lc = center of torsional rotation,

k x

k

i ii

n

ii

n=

=

∑

∑1

1

,

in cm or in.E = modulus of elasticity of the material, kN/m2

or psi.Ii = moment of inertia of the element being

considered.Li = span of cross structure, in cm or in., see

Figure 3/B.2

PART 3 APPENDIX 3/B|2 Guidance on Torsional Analysis of the Cross Deck Structure of a Multi-Hull Craft

FIGURE 3/B.2Span of Cross Structure

3/B.2 Torsional Section Modulus

The offered torsional section modulus of the crossstructure is determined by the lesser of the followingequations:

ZJ

ytt= Z

J

d ytt

cs

=−( )

Zt = torsion section modulus in cm3 or in3

ÿ = neutral axis of the cross deck structure.dcs = depth of cross deck, see figure 3/B.1

3/B.3 Maximum Stress on Each Element

3/B.3.1 DeflectionThe total amount that each element deflects can bedetermined by the following formula:

δ i

tt c

c ii

n

M x

x k

i

i

=

=∑

2

2

1

δi = deflection of each member in cm or in.Mtt = design torsional moment acting upon the

transverse structure connecting the hulls asdetermined 3/6.13.2 in kN-m or ft-lbs.

xci = xi - Lc in cm or in.xi, Lc, and ki are as defined in 3/B.1

3/B.3.2 Bending MomentThe bending moment that is acting on each element isdetermined by the following formula:

BMP L

ii i=2

BMi = bending moment that is acting on theelement under consideration in kN-cm, or in-lbs.

Pi = δiki , force that is acting on the element inkN or lbs.

Li = as defined in 3/B.1δi = as defined in 3/B.3.1ki = as defined in 3/B.10

3/B.3.3 Maximum StressThe maximum stress that is applied on each elementcan be determined by the following formula:

σ ii

i

BM

SM=

σi = maximum stress that is acting upon theelement in kN/m2 or psi.BMi = bending moment as defined in 3/B.3.2SMi = section modulus of the element beingconsidered in cm3 or in3

PART 3 APPENDIX 3/C|1 Guidance on First Ply Failure Analysis on FRP Sandwich Panels

PART 3 APPENDIX 3/C

Guidance on First Ply Failure Analysis onFRP Sandwich Panels

This appendix gives guidance on determining the offered section modulus of the inner and outer skins of an FRPsandwich laminate using first-ply failure analysis. First-ply failure analysis is done by determining the critical strainin which the first ply of the laminate will fail.

3/C.1 Offered Section Modulus of the Inner andOuter Skins of an FRP Laminate

3/C.1.1 Critical StrainThe critical strain of each ply can be determined bythe following equation:

[ ]εσ

critai

ai i ii E y y t

=− + 1

2

εcriti = critical strain of ply under consideration.σai = strength of ply under consideration in kN/m2

(kgf/m2, psi);= σt for a ply in the outer skin.= σc for a ply in the inner skin.

Eai = modulus of ply under consideration in kN/m2

(kgf/m2, psi);= Et for a ply in the outer skin.= Ec for a ply in the inner skin.

ÿ = distance from bottom of panel to the neutralaxis in cm or in.

yi = distance from the bottom of the panel to theply under consideration in cm or in.

ti = thickness of ply under consideration in cm orin.

σt = tensile strength of ply being considered.σc = compressive strength of ply being

considered.Et = tensile modulus of ply being considered.Ec = compressive modulus of ply being

considered.

3/C.1.2 Failure MomentThe failure moment of each ply in the laminate can bedetermined by the following equation:

( )FM E t y yi ai i i= −ε min

2

Eai, ti, ÿ, and yi are as defined in 3/C.1.1

FMi = portion of the total failure moment that eachply is to carry in kN-cm or in-lbs.

εmin = the smallest critical strain that is acting on anindividual ply.

3/C.1.3 Offered Section ModulusThe offered section modulus of the inner and outerskins of the laminate can be determined by thefollowing equations:

SM

FM

o

ii

n

to

= =∑

1

σ

SM

FM

i

ii

n

ci

= =∑

1

σ

SMo = offered section modulus of the outer skin incm3 or in3

SMi = offered section modulus of the inner skin incm3 or in3

FMi = as defined in 3/C.1.2n = total number of plies in the laminate.σto = tensile strength of outer skin, to be

determined by mechanical testing. Aweighted average of the individual plies ofthe tensile strengths of the outer skin may beused for preliminary estimations.

σci = compressive strength of inner skin, to bedetermined by mechanical testing. Aweighted average of the individual plies ofthe compressive strengths of the inner skinmay be used for preliminary estimations.

PART 4

Contents

Machinery Equipment and Systems

SECTION

1 Conditions of Classification of Machinery3 Gas Turbines4 Internal Combustion Engines and Reduction Gears5 Electrical Installations6 Pumps and Piping Systems7 Propulsion Shafting, Propellers, Waterjets and Lift Devices8 Steering9 Fire Extinguishing Systems

11 Shipboard Control and Monitoring Systems

PART 4 SECTION 1|1 Conditions of Classification of Machinery

PART 4 SECTION 1

Conditions of Classification of Machinery

4/1.1 General

The provisions of Section 1/1, Scope and Conditions ofClassification, are applicable to the classification ofmachinery.

4/1.2 Certification on Basis of an ApprovedQuality Assurance Program

Upon application, consideration will be given to theacceptance of standardized mass-produced machineryand machinery components without test and inspectionof individual units by the Surveyor subject to approvalof the manufacturer's quality assurance program.

4/1.5 Shipboard Automatic or Remote Controland Monitoring Systems

Shipboard automation, remote control and monitoringsystems are to comply with Section 4/11, as applicable.

4/1.11 Machinery Plans & Data

The following plans and data, as applicable for eachcraft to be built under survey, are to be submitted andapproved before construction is commenced inaccordance with 1/1.9. The sizes, dimensions, weldingand other details, make and size of standard approvedappliances are to be shown on the plans as clearly andfully as possible.

GeneralDetails of dead ship start arrangements (see 4/1.23)Description of all automatic trips that may affect the

craft’s propulsion system

Automation and Remote Control SystemsA list of electrical, pneumatic or hydraulic

equipment associated with the particular systemsincluding the data listed in 4/11.1.4a

A list of all major components installed within theparticular equipment (i.e., control console, etc.)and the data as required in 4/11.1.4a.

Certificates or test reports attesting to the suitabilityof the particular equipment in compliance withthe environmental criteria set forth in 4/11.3.7and 4/11.3.8, as applicable. For equipment thathave been already certified by the Bureau andprovided their certification remains valid, thesubmission of a copy of pertinent certificate willsuffice. (see 4/11.3.8b)

Plans showing the location of control andmonitoring stations, controlled equipment andpiping/cable runs, etc.

Arrangements and details of the control consolesand panels including plan views and elevationdetails, installation details and wiring data aslisted in 4/11.1.4e

A list of all cables connecting equipment associatedwith the systems (see 4/11.1.4f)

A complete operational description of the automaticor remote control and monitoring systems (see4/11.1.4g)

A simplified one-line diagram (electrical and piping)of all power and automatic or remote control andmonitoring systems (see 4/11.1.4h)

A schematic diagram of all control, alarm, displayand safety systems.

For computer-based systems, the following is to beincluded:

Overall description and specification of thesystems and equipment.

Block diagrams for the computer hardwareshowing interfacing between the workstations, input/output (I/O) units, localcontrollers, traffic controllers, datahighways, etc.

Logic flow chart or ladder diagrams.Description of the alarm system indicating

the ways it is acknowledged, displayedon the monitor or mimic display board,etc.

Description of the system redundancy andback-up equipment, if any.

Description of the data communicationprotocol including anticipated dataprocess response delays.

Description of the system' security protocolto prevent unauthorized programchanges which may compromise theintegrity of the automatic or remotesystems.

Description of the system with regard to thedegree of independence or redundancyprovided for the control systemsalarm/display systems and safetysystems.

Description of system's task priorities.


Where applicable, description of UPS(uninterruptable power supply) and theircapacities including system's powerconsumption.

Equipment ratings and environmentalparameters.

Installation methods (electrical, pneumatic andhydraulic) (see 4/11.1.4k)

A matrix chart for each of the systems indicating theinformation listed in 4/11.1.4l upon activation ofa given alarm or safety action:

Boilers, Pressure Vessels and Heat ExchangersArrangements and details of boilers, pressure

vessels and heat exchangers required bySection 4/2 of the Rules for Building andClassing Steel Vessels

Plans and data for hydraulic and pneumatic powercylinders as required by 4/6.69.2b

Electrical SystemsOne line diagrams for the following electrical

systems containing the information specified in4/5A1.1.2

Power supply and distributionLighting including navigating lightsInternal communicationGeneral emergency alarmFire detection and alarmSteering gear controlIntrinsically-safe equipmentEmergency generator startingSemiconductor converters for propulsion

Short-circuit data (see 4/5A1.3)Protective device coordination study (see 4/5A1.5)Electric-plant load analysis (see 4/5A1.7)Booklet of standard wiring practices and details (see

4/5B1.1)General arrangement plan of electrical equipment

showing the location of the equipment listed in4/5B1.3

Location of splices and cable boxes together withinformation of their services

Hazardous area plan (see 4/5B1.5)List of all equipment in hazardous areas (see

4/5B1.5)Details of electrical components as required by 4/5C

Fire SafetyArrangement and details of control station for

emergency closing of openings and stoppingmachinery

Details and location of fireman’s outfitsDetails of fire extinguishing appliancesFire control plans (see 4/9.1.7)Plans of the following systems:

Fire main systemFoam smothering systemFire detection systems

Fixed gas extinguishing systemFixed water spraying system

Other fire extinguishing arrangements

Gas TurbinesPlans and particulars as required by Section 4/3 of

the Rules for Building and Classing SteelVessels

Additionally, details of the manufacturer’s proposedautomatic safety devices in accordance with4/3.7.

Internal Combustion EnginesPlans and particulars as required by Section 4/4 of

the Rules for Building and Classing SteelVessels

Lift DevicesDetails and material specifications of force

transmitting partsDesign basis stress calculations for the propellers,

impellers, shafting, gears, belt drives,couplings, keys, bearings, and controlmechanism (see 4/7.38)

Piping SystemsDiagrammatic plans of the following piping systems

containing the information specified in 4/6.3.2Ballast systemBilge systemCompressed air systems (including starting

air systems and control systems)Cooling water systemsDeck drains and scuppersExhaust gas systemsEssential Fresh water service systemsFuel oil filling, transfer and service systemsHydraulic power piping systemsLubricating oil systemsPotable water systemSanitary systemEssential Sea water service systemsSteam systemVent, sounding and overflow pipingSystems conveying toxic liquids, liquids with

a flash point below 60C (140F), orflammable gases

All Group I piping systems not coveredabove unless it is part of anindependently manufactured unit (suchas air conditioning or refrigeration) thatdoes not form part of a ship’s pipingsystem

A booklet of standard piping practices and details(see 4/6.3.3)

Plans of molded or built-up flexible expansion jointsin seawater piping systems over 150 mm (6 in.),including details of the reinforcementarrangements (see 4/6.7.4)


Specifications for plastic pipes and components,including thermal and mechanical propertiesand chemical resistance (see 4/6.15, 4/6.17.6and 4/6.23.4))

Drawings of non-standard valves and fittingsshowing details of construction, materials andbasis for pressure rating (see 4/6.19.1b and4/6.21.3)

Valve operating systems for all remote-controlledvalves

PropellersFor all propellers (air or water), a propeller plan

giving design data and characteristics of thematerial

For skewed propellers or propeller blades of unusualdesign, a detailed stress analysis as required by4/7.23.2 or 4/7.25.2

For controllable pitch propellers, plans of thepropeller hub, propeller blade flange and bolts,internal mechanisms, hydraulic piping controlsystems, and instrumentation and alarmsystems; also strength calculations for theinternal mechanism

Detailed stress calculations and fitting instructionsfor keyless propeller connections

Reduction GearsArrangements, details and data as required by

Section 4/3 of the Rules for Building andClassing Steel Vessels

ShaftingDetailed plans with material specifications of the

propulsion shafting, couplings, coupling bolts,propulsion shafting arrangement, tailshaftbearings and lubrication system, if oil-lubricated,

Calculations for flexible couplings anddemountable couplings (see 4/4.19 and4/7.10.7)

Shaft alignment and vibration calculations ifrequired by 4/7.16

Detailed preloading and stress calculations andfitting instructions for non-fitted coupling bolts(see 4/7.10.3)

Steering GearGeneral arrangements of the main and auxiliary

steering gears and steering compartmentAssembly of upper rudder stock, tiller, tie rod,

rudder actuators, etc.Construction details of all torque-transmitting

components such as tiller, tiller pin,tiller/rudder stock interference fit mechanism,tie rod, rudder actuator, etc., including bill ofmaterials, welding procedures, and non-destructive testing, as applicable

Control system incorporating schematic electricalcontrol logic diagram, instrumentation, alarmdevices, etc. and including bill of materials

Design calculations for torque-transmittingcomponents such as tiller, tie rod, rudderactuator, etc.

Details of electrical power supply to power unitsand to steering gear control, includingschematic diagram of motor controllers, feedercables, and feeder cable electrical protection

Rated torque of main steering gearSchematic hydraulic piping plan incorporating

hydraulic logic diagram and including bill ofmaterials, typical pipe to pipe joint details, pipeto valve joint details, pipe to equipment jointdetails, pressure rating of valves and pipefittings, and pressure relief valve settings

Steering VanesDetails and material specifications of force

transmitting partsAirfoil analysis including vane freestream

characteristics (lift and drag characteristics)Control system arrangements

Thrusters (Steerable, Athwartship)Drawings and data as per 2.4 of the Guide for

Thrusters and Dynamic Positioning Systems

WaterjetsDetails and material specifications of force

transmitting partsDesign basis stress calculations for the impellers,

shafting, steering mechanism and reversingmechanism (see 4/7.36.3)

Calculations or test results to substantiate thesuitability and strength of the pressure andsuction housing (see 4/7.36.5)

Windlass or WinchArrangements, details and stress calculations for the

windlass or winch, drums, brakes, shaft, gears,coupling bolts, wildcat, sheaves, pulleys andfoundation

Control arrangementsElectric one-line diagram including power ratings

and cable specificationsPiping system diagram including working pressures,

welding details, material specifications and pipespecifications

4/1.15 Machinery Space

Machinery spaces are to be arranged so as to provideaccess to all machinery and controls as necessary foroperation or maintenance.


4/1.17 Definitions

For the purpose of machinery installations, electricalinstallations, periodically unattended machinery spaces,fire protection, fire detection and fire extinction, thefollowing terms are defined:

4/1.17.1 Category A Machinery SpacesMachinery spaces of Category A are those spaces andtrunks to such spaces that contain: internal combustionmachinery used for main propulsion; internalcombustion machinery used for purposes other thanmain propulsion where such machinery has anaggregate total power output of not less than 375 kW(500 HP); oil fired equipment such as an incinerator,waste disposal unit, etc.; or any oil fuel units.

4/1.17.2 Machinery SpacesMachinery spaces are Category A spaces and all otherspaces containing propelling machinery, internalcombustion engines, boilers, generators, majorelectrical equipment, refrigerating, stabilizing,ventilation and air conditioning machinery, similarspaces and trunks to such spaces.

4/1.17.3 Oil Fuel UnitAn oil-fuel unit is any equipment, such as pumps, filtersand heaters, used for the preparation and delivery offuel oil to oil-fired boilers (including incinerators),internal combustion engines or gas turbines at apressure of more than 1.8 bar (1.8 kgf/cm2, 26 psi).

4/1.17.4 Accommodation SpacesAccommodation spaces are those spaces used for publicspaces, corridors, lavatories, cabins, offices, hospitals,cinemas, games and hobbies rooms, barber shops,pantries containing no cooking appliances and similarspaces.

4/1.17.5 Public SpacesPublic spaces are those portions of the accommodationswhich are used for meeting halls, dining rooms,lounges, and similar permanently enclosed spaces.

4/1.17.6 Service SpacesService spaces are those spaces used for galleys,pantries containing cooking appliances, lockers, mailand specie rooms, storerooms, workshops other thanthose forming part of the machinery spaces, similarspaces and trunks to such spaces.

4/1.17.7 Cargo SpacesCargo spaces are all spaces, other than special categoryspaces, used for cargo and trunks to such spaces.

4/1.17.8 Special Category SpacesSpecial category spaces are those enclosed spacesintended for the carriage of motor vehicles with fuel in

their tanks for their own propulsion, into and fromwhich such vehicles can be driven, and to whichpassengers have access, including spaces intended forthe carriage of cargo vehicles.

4/1.17.9 Sources of IgnitionSources of ignition are considered to include a flame,arc, spark and electrical equipment, machinery andother equipment having hot surfaces with the potentialof causing a non-intentional explosion or fire whenexposed to an explosive or flammable atmosphere ormaterial.

4/1.17.10 Vital SystemsVital systems are those systems neccessary for thecraft’s survivability and safety including:

a Systems for fill, transfer, and service of fueloil.

b Fire-main systems, including emergency firepump

c Other required fire-extinguishing and detectionsystems.

d Bilge systems, including emergency bilgesuction

e Ballast systems.f Steering systems and steering control systems.g Propulsion systems and their necessary

auxiliaries (fuel oil, lube oil, cooling water,starting system, etc.) and control systems.

h Systems for transfer and control of cargoi Ship’s service and emergency electrical

generation systems and their auxiliaries (fueloil, lube oil, cooling water, starting system,etc.) and control systems.

j Venting and sounding systemsk Engine room ventilation systemsl Other required ventilation systemsm Controllable pitch propeller systems including

controlsn Electrical power and lighting systemso Systems used for navigationp Required communication and alarm systemsq Hydraulic systems for anchor windlass/winchr Systems necessary due to special

characteristics or special service of a crafts Any other system identified by the Bureau as

crucial to the survival of the craft or to theprotection of the personnel aboard.

4/1.17.11 Cargo CraftCargo craft is any craft which is not a passenger craft.

4/1.19 Astern Power

Astern power is to be provided in sufficient amount tosecure proper control of the ship in all normalcircumstances. The astern power of the main propelling


machinery is to provide for continuous operation asternat 70% of the ahead rpm at rated speed. For mainpropulsion systems with reversing gears, controllablepitch propellers or electric propulsion drive, runningastern is not to lead to overload of the propulsionmachinery.

4/1.21 Inclinations

All main propulsion machinery and all auxiliarymachinery essential to the propulsion and safety of thecraft, including the emergency source of power, is to bedesigned to operate when the craft is upright and wheninclined at any angle of list up to and including 15°either way under static conditions and 22.5° underdynamic conditions (rolling) either way andsimultaneously inclined dynamically (pitching) 7.5° bybow or stern. Lower angles may be specially acceptedtaking into consideration the type, size and serviceconditions of the craft.

4/1.23 Dead Craft Start

Means are to be provided to ensure that the machinerycan be brought into operation from a dead craftcondition (e.g. a condition under which the mainpropulsion plant, and auxiliaries are not in operationdue to an absence of power and normal starting energysources are depleted) without external aid.

4/1.25 Machinery Equations

The equations for rotating parts of the machinery in thefollowing sections are based upon strengthconsiderations only. Their application does not relievethe manufacturer from responsibility for the presence ofdangerous vibrations in the installation at speeds withinthe operating range. See also 4/7.16.

4/1.27 Machinery Space Ventilation

Machinery spaces are to be ventilated so as to ensurethat when machinery is operating at full power in allweather conditions, including heavy weather, anadequate supply of air is maintained for operation of themachinery and safety of the personnel.

4/1.29 Engineers' Alarm

Engineers’ alarms are required on craft of 500 grosstons and over, which are intended for internationalvoyages. An engineers' alarm is to be operable from themain propulsion control station. It is to be audible inthe engineers' accommodations. See 4/5A9.3.

4/1.31 Automatic Trips

A description of all automatic trips that may affect thecraft’s propulsion system is to be submitted for review.

4/1.33 Thrusters

Compliance with the Sections 2 and 4 of ABS'sseparately published, "Guide for Certification ofThrusters and Dynamic Positioning Systems" isrequired as a condition for Class for main propulsionthrusters and is optional for propulsion-assist thrusters,athwartship thrusters, and dynamic positioningthrusters.

4/1.35 Boilers, Pressure Vessels and Turbines

When fitted, boilers and pressure vessels are to bedesigned and constructed in accordance with Section4/2 of the Rules for Building and Classing SteelVessels. Turbines are to comply with Section 4/3 of theRules for Building and Classing Steel Vessels.

4/1.37 Sea Trial

4/1.37.1 GeneralA final underway trial is to be made of all machinery,including the steering gear, anchor windlass and groundtackle. The entire installation is to be operated in thepresence of the Surveyor to demonstrate its reliabilityand capability to function satisfactorily under operatingconditions and its freedom from harmful vibrationswithin the operating range. The ability of themachinery to reverse the direction of thrust of thepropeller from maximum ahead speed and bring thecraft to rest is to be demonstrated on sea trials to thesatisfaction of the Surveyor.

All automatic controls, including trips which mayaffect the craft's propulsion system, are to be testedunderway or alongside the pier, to the satisfaction of theSurveyor.

See also 4/4.23 and 4/8.8.2.

4/1.37.2 Residual FuelThe viscosity of the fuel used on the sea trial will beentered in the classification report.

4/1.39 Units

These Rules are written in three systems of units, i.e., SIunits, MKS units and US customary units. Each systemis to be used independently of any other system. Theformat presentation in the Rules of the three systems ofunits is as follows;

SI units (MKS units, US customary units) unlessindicated otherwise.

PART 4 SECTION 3|1 Gas Turbines

PART 4 SECTION 3

Gas Turbines

4/3.1 General

All gas turbines of 100 kW (135 horsepower) andover and associated reduction gears are to beconstructed and installed in accordance with Section4/3 of the Rules for Building and Classing SteelVessels.

Gas turbines of less than 100 kW (135horsepower) and associated reduction gears are to beconstructed and equipped in accordance with goodcommercial practice, and will be accepted subject to asatisfactory performance test conducted to thesatisfaction of the Surveyor after installation.

All gas turbines are also to meet the requirementsin this Section.

4/3.3 Piping Systems

Piping systems for gas turbines are to comply with theapplicable requirements in Section 4/6 in addition tothis Section.

4/3.5 Pressure Vessels and Heat Exchangers

Pressure Vessels and heat exchangers associated withgas turbine are to be in accordance with theapplicable requirements of Section 4/2 of the Rulesfor Building and Classing Steel Vessels.

4/3.7 Automatic Safety Devices

Details of the manufacturer’s proposed automaticsafety devices to guard against hazardous conditionsarising in the event of malfunction in the turbineinstallation are to be provided together with thefailure mode and effect analysis.

4/3.9 Fuel Oil Systems

In addition to 4/6.49, 4/6.51 and 4/6.55, fuel oilsystems for gas turbines are to comply with thefollowing:

4/3.9.1 Pumps, Heater and StrainersThere are to be at least two independent fuel oilservice pumps, each of sufficient capacity to supplyturbines at full power and arranged that one may beoverhauled while the other is in service.. Oil heatersare to be similarly installed in multiples.

Oil strainers are to be installed in the suction anddischarge lines and are to be either of the duplex type

or other approved filter which is capable of beingcleaned without interrupting the oil supply. Wherestrainers are fitted in parallel to enable cleaningwithout disrupting the oil supply, means are to beprovided to minimize the possibility of a strainerunder pressure being opened inadvertently. Strainersare to be provided with suitable means for ventingwhen being put into operation and beingdepressurized before being opened. Valves or cockswith drain pipes led to a safe location are to be usedfor this purpose.

4/3.9.2 Pressure PipingOil pressure piping between the service pumps andthe gas turbines is to be so located as to be readilyobservable and is to have a relief valve fitted whichwill discharge into the suction line or back into thetank. Piping between the service pumps and the gasturbine is to be of extra-heavy seamless or electricresistance welded (ERW) steel, except that, if shut-offvalves are fitted between the pumps and the turbines,short flexible connections of appropriate materialmay be used between the valves and the turbines.

High pressure fuel oil piping is to be shielded orotherwise protected to avoid, as far as practicable, oilspray or oil leakages onto hot surfaces withtemperatures in excess of 220C (428F), intomachinery air intakes or other sources of ignition.

4/3.9.3 Drainage of Excess FuelProvision is to be made to drain all excess fuel oil,particularly fuel which might reach the interior of thejet pipe or exhaust system after a false start or afterstopping, to a safe position so as to avoid a firehazard.

4/3.9.4 Low Flash Point Fuel For Gas TurbinesFuel with a flash point below 43C (109F), but not lessthan 35C (95F), may be permitted for gas turbineinstallations provided the arrangements for thestorage, distribution and utilization of the fuel aresuitable with regard to the hazard of fire andexplosion which the use of such fuel may entail, thesafety of the craft and persons on board is preserved.The arrangements are to comply with the followingprovisions:

PART 4 SECTION 3|2 Gas Turbines

a Tanks for the storage of such fuel are to belocated outside any machinery space and at a distanceof not less than 760 mm (30 in.) inboard from theshell side and bottom plating and from decks andbulkheads.

b Arrangements are to be provided to preventoverpressure in any fuel tank or in any part of the oilfuel system, including the filling pipes. Any reliefvalves and air or overflow pipes are to discharge to asafe position and are to terminate with approvedflame arresters.

c The spaces in which fuel tanks are located areto be mechanically ventilated, using exhaust fansproviding not less than six air changes per hour. Thefans are to be such as to avoid the possibility ofignition of flammable gas-air mixtures. Suitable wiremesh guards are to be fitted over inlet and outletventilation openings. The outlets for such exhaustsare to be discharged to a safe position. ‘NoSmoking’ signs are to be posted at a the entrances tosuch spaces.

d Earthed electrical distribution systems are notto be used, with the exception of earthed intrinsicallysafe circuits.

e Suitable certified safe type electrical equipmentis to be used in all spaces where fuel leakage couldoccur, including the ventilation system. Onlyelectrical equipment and fittings essential foroperational purposes are to be fitted in such spaces.See 4/5B7.3.

f A fixed vapor detection system is to be installedin each space through which fuel lines pass, withalarms provided at the continuously manned controlstation.

g Every fuel tank is, where necessary, to beprovided with “savealls” or gutters which would catchany fuel which may leak from such tank.

h Craft-to-shore fuel connections are to be ofclosed type and are to be provided with suitablyearthing arrangements to be used during bunkeringoperations. ‘No Smoking’ and ‘No Naked Lights’signs are to be posted in the vicinity of the bunkeringstation.

i Each space containing a non-integral fuel tank isto be fitted with a fire-detection systems complyingwith 4/9.23 and a fire extinguishing systemcomplying with 4/9.25.

4/3.11 Starting Arrangements

Starting arrangements for gas turbine installations areto be capable of providing an equivalent number ofstarts as that required for diesel engines in 4/4.15.

4/3.13 Exhaust Systems

Exhaust systems are to comply with 4/6.63. Inaddition, gas turbine exhausts are to be located andarranged so that hot exhaust gases are directed awayfrom walkways and other areas to which personnelhave access.

4/3.15 Turbine Enclosures

Where an acoustic enclosure is fitted whichcompletely surrounds the gas turbine and the high-pressure oil pipes, a fire detection and extinguishingsystem is to be provided for the acoustic enclosure.

4/3.17 Turbines Driving Generators

Gas turbines driving generators are also to complywith 4/5C2.15.

PART 4 SECTION 4|1 Internal Combustion Engines and Reduction Gears

PART 4 SECTION 4

Internal Combustion Enginesand Reduction Gears

4/4.1 General

4/1.1 Construction and InstallationInternal combustion engines of 100 kW (135horsepower (hp)) and over and associated reductiongears are to be constructed in accordance withSection 4/4 the "Rules for Building and ClassingSteel Vessels" and installed in accordance with thefollowing requirements, to the satisfaction of theSurveyor. Engines of less than 100 kW (135 hp) andassociated reduction gears are to be constructed andequipped in accordance with good commercialpractice, and will be accepted subject to satisfactoryperformance test conducted to the satisfaction of theSurveyor after installation.

For engines driving generators, see also 4/5C2.17.

4/4.1.3 Piping SystemsIn addition to requirements for specific system in thissection, piping systems are to comply with theapplicable requirements in Section 4/6.

4/4.1.5 Pressure Vessels and Heat ExchangersPressure vessels and heat exchangers are to be inaccordance with the applicable requirements ofSection 4/2 of the "Rules for Building and ClassingSteel Vessels".

4/4.1.7 Torsional Vibration StressesRefer to 4/7.16.

4/4.1.11 Crankcase Ventilationa General Provision is to be made for

ventilation of an enclosed crankcase by means of asmall breather or by means of a slight suction notexceeding 25.4 mm (1 in.) of water. Crankcases arenot to be ventilated by a blast of air. Otherwise, thegeneral arrangements and installation are to be suchas to preclude the possibility of free entry of air to thecrankcase.

b Piping Arrangement Crankcase ventilationpiping is not to be directly connected with any otherpiping system. Crankcase ventilation pipes from eachengine are normally to be led independently to theweather and fitted with corrosion resistant flamescreens; however, crankcase ventilation pipes from

two or more engines may lead to a common oil mistmanifold.

Where a common oil mist manifold is employed,the vent pipes from each engine are to be ledindependently to the manifold and fitted with acorrosion resistant flame screen within the manifold.The arrangement is not to violate the enginemanufacturer’s recommendations for crankcaseventilation. The common oil mist manifold is to beaccessible at all times under normal conditions andeffectively vented to the weather. Where venting ofthe manifold to the weather is accomplished by meansof a common vent pipe, the location of the manifoldis to be as close as practicable to the weather suchthat the length of the common vent pipe is no greaterthan one deck height. The clear open area of thecommon vent pipe is not to be less than the aggregatecross-sectional area of the individual vent pipesentering the manifold, and the outlet to the weather isto be fitted with a corrosion resistant flame screen.The manifold is also to be fitted with an appropriatedraining arrangement.

4/4.1.13 Warning NoticesSuitable warning notices are to be attached in aconspicuous place on each engine and are to cautionagainst the opening of a hot crankcase for a specifiedperiod of time after shutdown based upon the size ofthe engine, but not less than 10 minutes in any case.Such notice is also to warn against restarting anoverheated engine until the cause of overheating hasbeen remedied.

4/4.1.15 BedplateThe bedplate or crankcase is to be of rigidconstruction, oiltight, and provided with a sufficientnumber of bolts to secure the same to the ship'sstructure. The structural arrangements for supportingand securing the main engines are to be submitted forapproval. Refer to 3/7.11 for structural requirements.For welded construction see also Section 2/3.

4/4.1.17 Engine Air Intake SystemsEngine air intakes are to be provided with filters toprotect against damage from foreign matter.


4/4.3 Fuel Oil Pumps and Oil Heaters

4/4.3.1 Transfer pumpsRefer to 4/6.51.

4/4.3.3 Booster pumpsA stand-by fuel-oil booster pump is to be providedfor main engines having independently driven boosterpumps. For main engines having attached fuelpumps, a complete pump may be carried as a spare inlieu of the standby pump. For multiple engines usingidentical attached fuel pumps, only one completepump needs to be carried as a spare. A spare fuel oilbooster pump will not be required where it can beproven through a FMEA that the vessel is capable ofsafely returning to a port of refuge under allconditions.

4/4.3.5 HeatersWhen fuel oil heaters are required for main engineoperation, at least two heaters of approximately equalsize are to be installed. The combined capacity of theheaters is to be not less than required to supply themain engine(s) at full power.

4/4.5 Fuel oil Pressure Piping

Pipes from booster pumps to injection systems are tobe at least standard seamless steel. Pipes conveyingheated oil are to be at least standard seamless orelectric-resistance-welded steel. ERW pipe is to bestraight seam and fabricated with no filler metal (e.g.,ABS Grade 2 or 3 ERW). Valves and fittings may bescrewed in sizes up to and including 60 mm O.D. (2in. N.P.S.), but screwed unions are not to be used onpressure lines in sizes 33 mm O.D. (1 in.) and over.Valves are to be so constructed as to permit packingunder pressure.

4/4.7 Fuel oil Injection System

4/4.7.1 GeneralStrainers are to be provided in the fuel oil injectionpump suction line.

For main propulsion engines, the arrangement isto be such that the strainers may be cleaned withoutinterrupting the fuel supply to the engine. However,where multiple engines are provided, a dedicatedsimplex strainer may be fitted for each engineprovided the craft can maintain at least one-half of thedesign speed or 7 knots, whichever is less, whileoperating with one engine temporarily out of serviceuntil its strainer can by cleaned.

For auxiliary engines the arrangement is to besuch that the strainers may be cleaned without undueinterruption of power necessary for propulsion.Multiple auxiliary engines, each fitted with a separatestrainer and arranged such that change over to a

standby unit can be accomplished without loss ofpropulsion capability, will be acceptable for thispurpose.

Where strainers are fitted in parallel to enablecleaning without disrupting the oil supply, means areto be provided to minimize the possibility of astrainer being opened inadvertently. Strainers are tobe provided with suitable means for venting whenbeing put in operation and being depressurized beforebeing opened. trainers are to be so located that in theevent of leakage oil cannot be sprayed on to theexhaust manifold or surfaces with temperatures inexcess of 220C (428F).

The injection lines are to be of seamless drawnpipe. Fittings are to be extra heavy. The materialused may be either steel or nonferrous as approved inconnection with the design. Also refer to 4/6.51.4.

4/4.7.3 Shielding of High Pressure Fuel OilPiping

On all main and auxiliary engines having a cylinderbore of 250 mm (10 in.) and above, the high pressurefuel oil injection piping is to be effectively shieldedand secured to prevent fuel or fuel mist from reachinga source of ignition on the engine or its surroundings.Suitable arrangements are to be made for drainingany oil-fuel leakage and for preventing contaminationof lubrication oil by fuel oil. If flexible hoses areused for shielding purpose, these are to be of anapproved type. When the peak to peak pressurepulsation in return piping exceeds 19.7 bar (20kgf/cm2, 285 psi), shielding of this piping is alsorequired.

4/4.9 Lubricating Oil Systems

4/4.9.1 GeneralThe following requirements are applicable for mainand auxiliary diesel engines and for reduction gearsassociated with diesel propulsion. See also 4/1.21and 4/6.59.

4/4.9.3 Low Oil Pressure Alarms, Temperatureand Level Indicators

An alarm device with audible and visual signals forfailure of the lubricating oil system is to be fitted.Pressure and temperature indicators are to be installedin lubricating oil systems indicating that the propercirculation is being maintained.

4/4.9.5 Drain PipesLubricating oil drain pipes from the sump to the draintank are to be submerged at their outlet ends.

No interconnection is to be made between thedrain pipes from the crankcases of two or moreengines.


4/4.9.7 Lubricating Oil PumpsIn cases where forced lubrication is used forpropulsion engines, one independently driven standbypump is to be provided in addition to the necessarypumps for normal operation. Where the size anddesign of an engine is such that lubrication beforestarting is not necessary and an attached lubricatingpump is normally used, an independently drivenstandby pump is not required if a complete duplicateof the attached pump is carried as a spare. Formultiple engines using identical attached lubricating-oil pumps, only one complete pump needs to becarried as a spare. A spare lube oil pump will not berequired where it can be proven through a FMEA thatthe vessel is capable of safely returning to a port ofrefuge under all conditions.

4/4.9.9 FiltersOil filters are to be provided. In the case of mainpropulsion engines which are equipped with full-flow-type filters, the arrangement is to be such thatthe strainers may be cleaned without interrupting theoil supply. However, where multiple engines areprovided, a dedicated simplex strainer may be fittedfor each engine provided the craft can maintain atleast one-half of the design speed or 7 knots,whichever is less, while operating with one enginetemporarily out of service until its filter can bycleaned.

For auxiliary engines the arrangement is to besuch that the filters may be cleaned without undueinterruption of power necessary for propulsion.Multiple auxiliary engines, each fitted with a separatefilter and arranged such that change over to a standbyunit can be accomplished without loss of propulsioncapability, will be acceptable for this purpose.

The arrangement of the valving is to be such as toavoid release of debris into the lubricating-oil systemupon activation of the relieving mechanism.

Where filters are fitted in parallel to enablecleaning without disrupting the oil supply, means areto be provided to minimize the possibility of a filterunder pressure being opened inadvertently. Filtersare to be provided with suitable means for ventingwhen being put in operation and being depressurizedbefore being opened. Filters are to be so located thatin the event of leakage, oil cannot be sprayed ontosurfaces with temperatures in excess of 220C (428F).

4/4.9.13 Lubricating-Oil Systems for ReductionGears

Where a reduction gear is driven by a single engineand a common lubricating-oil system is used for boththe engine and gear, the requirements in 4/4.9.1through 4/4.9.9 are applicable.

Where a reduction gear is driven by more thanone engine and any other case where a separatelubricating-oil system is provided for the reductiongear, the following requirements are applicable.

a Pumps Two lubricating-oil pumps are to beprovided, at least one of which is to be independentlydriven. The capacity of each pump is to be sufficientfor continuous operation of the main propulsion plantat its maximum rated power.

b Coolers One or more lubricated-oil coolerswith means for controlling the oil temperature is to beprovided together with two separate cooling waterpumps, at least one of which is to be independentlydriven. The coolers are to have sufficient capacity tomaintain the required oil temperature while the mainpropulsion plant is operating continuously at itsmaximum rated power.

c Indicators Indicators are to be fitted by whichthe pressure and temperature of the water inlet and oiloutlet may be determined. Gravity tanks are to befitted with a low level alarm and a sight glass is to befitted in the overflow line to the sump. Pressuresystems are to be fitted with a low pressure alarm.Sump and gravity tanks are to be provided withsuitable gauges for determining the level of oil withinthe tank.

d Filters A filter is to be provided in thelubricating-oil piping to each reduction gear. Therequirements in 4/4.9.9 are applicable.

4/4.11 Cooling Water Systems

4/4.11.1 GeneralMeans are to be provided to ascertain the temperatureof the circulating water at the return from each engineand to indicate that the proper circulation is beingmaintained. Drain cocks are to be provided at thelowest point of all jackets. For relief valves, see4/6.7.9.

4/4.11.3 Sea SuctionsAt least two independent sea suctions are to beprovided for supplying water to the engine jackets orto the heat exchangers, except that for multihull craftclassed with restricted service, special considerationmay be given. The sea suctions are to be located asto minimize the possibility of blanking off the coolingwater. For multiple engine installations fitted withindividual sea suctions for each engine, two means ofsupplying cooling water to each engine may beomitted where it can be proven through a FMEA thatthe vessel is capable of safely returning to a port ofrefuge under all conditions.


4/4.11.5 StrainersWhere seawater is used for direct cooling of theengines, unless other equivalent arrangements arespecially approved, suitable strainers are to be fittedbetween the sea valves and the pump suctions. Thestrainers are to be either of the duplex type orotherwise arranged so they can be cleaned withoutinterrupting the cooling water supply.

4/4.11.7 Circulating Water PumpsThere are to be at least two means for supplyingcooling water to main and auxiliary engines,compressors, coolers, reduction gears, etc. One ofthese means is to be independently driven and mayconsist of a connection from a suitable pump ofadequate size normally used for other purposes, suchas a general service pump, or in the case of fresh-water circulation one of the craft’s fresh-waterpumps. Where, due to the design of the engine, theconnection of an independent pump is impracticable,the independently driven stand-by pump will not berequired if a complete duplicate of the attached pumpis carried as a spare. For multiple propulsion enginesusing identical attached pumps, only one completepump needs to be carried as a spare. Multipleauxiliary engine installations utilizing attached pumpsneed not be provided with spare pumps. A sparecooling water pump will not be required where it canbe proven through a FMEA that the vessel is capableof safely returning to a port of refuge under allconditions.

4/4.15 Starting Systems

4/4.15.1 Starting Air SystemsThe design and construction of all air receivers are tobe in accordance with the applicable requirements ofSection 4/2 of the Rules for Building and ClassingSteel Vessels. The piping system is to be inaccordance with the applicable requirements ofSection 4/6 of these Rules. The air receivers are to beso installed as to make the drain connections effectiveunder extreme conditions of trim. Compressed airsystems are to be fitted with relief valves and eachcontainer which can be isolated from a relief valve isto be provided with a suitable fusible plug to relievethe pressure in case of fire. Connections are also tobe provided for cleaning the air container and pipelines.

All discharge pipes from starting air compressorsare to be led directly to the starting air receivers, andall starting pipes from the air receivers to main orauxiliary engines are to be entirely separate from thecompressor discharge piping system.

4/4.15.3 Starting Air CapacityCraft having main engines arranged for air startingare to be provided with at least two starting-aircontainers of approximately equal size. The totalcapacity of the starting-air containers is to besufficient to provide, without recharging thecontainers, at least the number of starts stated below.

If other compressed air systems, such as controlair, are supplied from starting air containers, thecapacity of the containers is to be sufficient forcontinued operation of these systems after the airnecessary for the required number of consecutivestarts has been used.

a Diesel Propulsion The minimum number ofconsecutive starts (total) required to be provided fromthe starting-air containers is to be based upon thearrangement of the engines and shafting systems asindicated in the following table.

Single Screw Craft Multiple Screw Craft

One enginecoupled to

shaftdirectly

or thru

reductiongear

Two or moreengines

coupled toshaft thruclutch andreduction

gear

One enginecoupled toeach shaft

directlyor

thrureduction

gear

Two or moreengines

coupled toeach shaftthru clutch

andreduction

gearReversible

Engines12 16 16 16

Non-reversibleEngines

6 8 8 8

For arrangements of engine and shafting systemswhich differ from those indicated in the table, thecapacity of the starting-air containers will be speciallyconsidered based on an equivalent number of starts.

b. Diesel-electric Propulsion The minimumnumber of consecutive starts required to be providedfrom the starting-air containers is to be determinedfrom the following equation.

S = 6 + G(G-1)

whereS = total number of consecutive startsG = number of engines driving the propulsion

generators but the value of G need notexceed 3.

4/4.15.5 Starting Air CompressorsFor craft having internal-combustion enginesarranged for air starting, there are to be two or moreair compressors, at least one of which is to be drivenindependently of the main propulsion unit, and thetotal capacity of air compressors drivenindependently of the main propulsion unit is to be notless that 50% of the total required.


The total capacity of the air compressors is to besufficient to supply within one hour the quantity ofthe air need to satisfy 4/4.15.3 by charging thereceivers from atmospheric pressure. The capacity isto be approximately equally divided between thenumber of compressors fitted, excluding anemergency compressor where fitted.

The arrangement for dead craft air starting is to besuch that the necessary air for the first charge can beproduced on board without external aid. See 4/1.23.

4/4.15.7 Protective Devices for Starting-air MainsIn order to protect starting air mains againstexplosions arising from improper functioning ofstarting valves, an isolation non-return valve orequivalent is to be installed at the starting air supplyconnection to each engine. Where engine boresexceed 230 mm (9 1/16 in.), a bursting disc or flamearrester is to be fitted in way of the starting valve ofeach cylinder for direct reversing engines having amain starting manifold or at the supply inlet to thestarting-air manifold for nonreversing engines.

The above requirement is applicable to engineswhere the air is directly injected into the cylinder. Itis not intended to apply to engines utilizing air startmotors.

4/4.15.9 Electrical Startinga Main Engine Where the main engine is

arranged for electric starting, at least two separatebatteries ( or separate set of batteries) are to be fitted.The arrangement is to be such that the batteries (or setof batteries) cannot be connected simultaneously inparallel. Each battery (or set) is to be capable ofstarting the main engine when in cold and ready tostart conditions. The combined capacity of thebatteries is to be sufficient without recharging toprovide within 30 minutes the number of starts ofmain engines as required for air starting in 4/4.15.3,and if arranged also to supply starting for auxiliaryengines the number of starts required in b. See also c.

b Auxiliary Engine Electric startingarrangements for auxiliary engines are to have at leasttwo separate batteries (or separate set of batteries) ormay be supplied by separate circuits from the mainengine batteries when such are provided. Where oneauxiliary engine is arranged for electric starting, onebattery (or set) may be accepted in lieu of twoseparate batteries (or sets). The capacity of thebatteries for starting the auxiliary engines is to besufficient for at least three starts for each engine.

c Other Requirements The starting batteries (orset of batteries) are to be used for starting and forengine’s own control and monitoring purpose only,When the starting batteries are used for engine’s owncontrol and monitoring purpose, the aggregatecapacity of the batteries is to be sufficient forcontinued operation of such system in addition to the

required number of starting capacity. Provisions areto be made to maintain continuously the stored energyat all times. See also 4/5A3.17 and 4/5B2.7.

4/4.15.11 Hydraulic StartingHydraulic oil accumulators for starting the mainpropulsion engines are to have sufficient capacitywithout recharging for starting the main engines asrequired in 4/4.15.3.

4/4.17 Engine Exhaust SystemsEngine exhaust systems are to comply with 4/6.63. Inaddition, propulsion engines with bores exceeding200 mm (7.87 in.) are to be fitted with a means todisplay the exhaust gas temperature of each cylinder.

4/4.19 Couplings

4/4.19.1 Flexible Shaft CouplingsDetails of the various components of flexiblecouplings for main propulsion machinery and ship'sservice generator sets are to be submitted forapproval. Flexible couplings with elastomer or springtype flexible members and which represent the solesource of transmitting propulsive power in a line shafton a single screw craft are to be provided withtorsional limit capacity (coupling will lock beyond itslimit) or positive means of locking the coupling.Operation of the craft with a locked coupling may beat reduced power provided warning notices are postedat the control station.

4/4.19.3 Flanged Couplings and Coupling BoltsRefer to 4/7.10.5, for flanged couplings.

Elongation for auxiliary machinery coupling boltsmade of steel having an ultimate tensile strength over690 N/mm2 (70 kgf/mm2, 100,000 psi) will be subjectto special consideration. Also refer to 4/7.10.1 and4/7.10.3.

4/4.21 Testing of Pumps Associated with Engineand Reduction Gear Operation

Pumps associated with engine and reduction gearoperation (oil, water, fuel) utilized with engineshaving bores exceeding 300 mm (11.8 in.) are to beprovided with certificates issued by the Surveyor.The following tests are to be conducted to theSurveyor's satisfaction:

4/4.21.1 Pumps Hydrostatic TestsIndependently-driven pumps are to be hydrostaticallytested to 4 bar (4 kgf/cm2, 57 psi) but not less than1.5P, where P is the maximum working pressure inthe part concerned.


4/4.21.3 Capacity TestsTests of pump capacities are to be conducted to thesatisfaction of the Surveyor with the pump operatingat design conditions. Capacity tests will not berequired for individual pumps produced on aproduction line basis, provided the Surveyor issatisfied from periodic inspections and themanufacturer's quality assurance procedures that thepump capacities are acceptable.

4/4.23 Trial

Before final acceptance, the entire installation is to beoperated in the presence of the Surveyor todemonstrate its ability to function satisfactorily under

operating conditions and its freedom from harmfulvibration at speeds within the operating range. Seealso 4/1.37.

For conventional propulsion gear units above1120 kW (1500 HP) a record of gear-tooth contact isto be made at the trials. To facilitate the survey ofextent and uniformity of gear-tooth contact, selectedbands of pinion or gear teeth on each meshing are tobe coated beforehand with copper or layout dye. See1/3.9.1b.

The gear-tooth examination for conventional gearunits 1120 kW (1500 HP) and below and all epicyclicgear units will be subject to special consideration.The gear manufacturer's recommendations will beconsidered.

PART 4 SECTION 5||||1 Electrical Installations -- General

PART 4 SECTION 5

Electrical Installations

This Section consists of the following parts:

General “General” for descriptions and requirements applicable to systems, installations, machinery andequipment in general.

Part A “Systems” for specific requirements necessary for initial planning and basic design of electricalsystems.

Part B “ Installations” for specific requirements necessary for the subsequent outfitting, selection of themachinery/equipment, etc.

Part C “Machinery and Equipment” for requirements for procured equipment.Part D “Specialized Installations” for supplemental requirements for high voltage system, electric

propulsion system and system of less than 75 kW.Part E “Specialized Vessels and Services” for supplemental requirements for installations in special-

category spaces.

General

4/5.1 Applications

Electrical apparatus and wiring systems are to beconstructed and installed to the satisfaction of theSurveyor in accordance with this Section. Thefollowing are minimum requirements for classificationpurposes. Consideration will be given, however, toarrangements or details which can be shown to complywith other recognized standards, provided they are notless effective.For craft having an aggregate generator capacity notexceeding 75 kW, the requirements contained in 4/5D3are to be complied with. Electrical installations inmachinery spaces with gasoline engines will bespecially considered.For passenger craft, see Section 5/1.

4/5.3 Definition

The following definitions apply for the purpose of thisSection.

4/5.3.1 Earthed Distribution SystemA system in which one pole of a single phase system orthe neutral point of a three phase system is earthed butthe earthing connection does not normally carrycurrent.

4/5.3.2 Essential ServicesServices essential for the navigation, steering andmaneuvering, or for special characteristics (e.g. special

services) of the craft, or for the safety of human life.

4/5.3.3 Explosion-proof (Flameproof) EquipmentExplosion-proof equipment is an equipment:

a Having an enclosure capable of:1 Withstanding an explosion within it of a

specified flammable gas or vapor, and2 Preventing the ignition of the specified

flammable gas or vapor in the atmospheresurrounding the enclosure by sparks, flashesor explosions of the gas or vapor within, and

b Operates at such an external temperature that asurrounding flammable atmosphere will not be ignited.Where explosion-proof equipment is required by thisGuide, equipment certified as being flameproof asdefined in IEC Publication 79 or other recognizedstandard may be accepted.

4/5.3.4 Hazardous Area (Hazardous Location)An area where flammable or explosive vapor, gas, ordust, or explosives may normally expected toaccumulate.

4/5.3.5 Hull-return SystemA system in which insulated conductors are providedfor connection to one pole or phase of the supply, thehull of the craft or other permanently earthed structurebeing used for effecting connections to the other poleor phase.


4/5.3.6 Intrinsically-safeA circuit or part of a circuit is intrinsically-safe whenany spark or any thermal effect produced in the testconditions prescribed in a recognized standard (such asIEC Publication 79-11) is incapable of causing ignitionof the prescribed explosive gas atmosphere.

a Category “ia” Apparatus which is incapable ofcausing ignition in normal operation, or with a singlefault, or with any combination of two faults applied,with the following safety factors:

- in normal operation: 1.5- with one fault: 1.5- with two faults: 1.0

Above safety factors are applied to the current, voltage,or their combination as specified in 10.4.1 of IECPublication 79-11.

4/5.3.7 Increased SafetyType of protection applied to electrical apparatus thatdoes not produce arcs or sparks in normal service, inwhich additional measures are applied so as to giveincreased security against the possibility of excessivetemperatures and of the occurrence of arc and sparks.See IEC Publication 79-7.

4/5.3.8 Non-Periodic Duty RatingA rating at which the machine is operated continuouslyor intermittently with varying the load and speed withinthe permissible operating range. The load and speedvariations include the overloads applied frequently,which may be greatly exceed the full load rating of themachine.

4/5.3.9 Non-sparking FanA fan consisting of a combination of impeller andhousing which are unlikely to produce sparks by staticelectricity or by entry of foreign objects in both normaland abnormal conditions.

4/5.3.10 Periodic Duty RatingA rating at which the machine is operated repeatedly oncycle of sequential loading with starting, electricbraking, no-load running, rest and de-energized periodswhere applicable. The time for the duration ofoperating cycle (duty cycle) is to be 10 minutes and theratio (i.e., cyclic duration factor) between the period ofloading (including starting and electric braking) and theduty cycle is to be one of the values of 15%, 25%,40%, or 60%.

4/5.3.11 Portable ApparatusPortable apparatus is any apparatus served by a flexiblecord.

4/5.3.12 Pressurized EquipmentEquipment having an enclosure in which positivepressure is maintained to prevent against the ingress ofexternal atmosphere and complying with therequirements in 4/5B7.3.3.

4/5.3.13 Semi-enclosed SpaceA space limited by decks and/or bulkheads in such amanner that the natural conditions of ventilation in thespace are notably different from those obtained on opendeck.

4/5.3.14 Separate CircuitA circuit which is independently protected by a circuitprotection device at the final sub-circuit and isdedicated to a single load.

4/5.3.15 Short CircuitA short circuit is an abnormal connection through anegligible impedance, whether made accidentally orintentionally, between two points of different potentialin a circuit.

4/5.3.16 Short-time RatingA rating at which the machine is operated for a limitedperiod which is less than that required to reach thesteady temperature condition, followed by a rest andde-energized period of sufficient duration to re-establish the machine temperature within 2 oC (3.6 oF)of the coolant.

4/5.5 Plans and Data to Be Submitted

See 4/5A1, 4/5B1, 4/5C1 and 4/5D2.3.

4/5.7 Standard Distribution System

The following are recognized as standard systems ofdistribution. The distribution systems differing fromthese will be specially considered.

- Two-wire direct current- Three-wire direct current- Two-wire single-phase alternating current- Three-wire three-phase alternating current*- Four-wire three-phase alternating current

* Three-wire single-phase A.C. may be used inconjunction with this system for lighting.

However, the electrical distribution voltagesthroughout the craft are not to exceed:

- 500 V for power, cooking, heating and otherpermanently connected equipment; and

- 250 V for lighting, internal communications andreceptacle outlets.


Subject to the acceptance by the Administration,high voltage systems as outlined in 4/5D1 may beacceptable for propulsion systems.

4/5.9 Voltage and Frequency Variations

Electrical appliances supplied from the main oremergency systems other than battery supplied are tobe so designed and manufactured that they are capableof being operated satisfactorily under the normallyoccurring variations in voltage and frequency. Unlessotherwise stated, the variations from the rated valuemay be taken from the Table 4/5.1. Any special system,e.g. electronic circuits, which cannot operatesatisfactorily within the limit shown in the Table is tobe supplied through a stabilized supply.

4/5.11 Materials

All electrical equipment is to be constructed of durableand flame-retardant materials. Materials are to beresistant to corrosion, moisture, high and lowtemperatures, and are to have other qualities necessaryto prevent deterioration in the ambient conditions theequipment may be expected to encounter.

4/5.13 Insulation Material

For the purpose of these requirements insulatingmaterial is designated as follows.

4/5.13.1 Class A InsulationMaterials or combinations of materials such as cotton,silk and paper when suitably impregnated or coated orwhen immersed in a dielectric liquid such as oil. Othermaterials or combinations of materials may be includedin this class if, by experience or accepted tests, they canbe shown to be capable of operation at 105 oC (221 oF).

4/5.13.2 Class B InsulationMaterials or combinations of materials such as mica,glass fiber, etc., with suitable bonding substances.Other materials or combinations of materials, notnecessarily inorganic, may be included in this class if,by experience or accepted tests, they can be shown tobe capable of operation at 130 oC (266 oF).

4/5.13.3 Class E InsulationMaterials or combinations of materials which, byexperience or accepted tests, can be shown to becapable of operation at 120 oC (248 oF) (materialspossessing a degree of thermal stability allowing themto be operated at a temperature 15 oC (27 oF) higherthan Class A materials).

4/5.13.4 Class F InsulationMaterials or combinations of materials such as mica,glass fiber, etc., with suitable bonding substances.Other materials or combinations of materials, notnecessarily inorganic, may be included in this class if,by experience or accepted tests, they can be shown tobe capable of operation at 155 oC (311 oF).

4/5.13.5 Class H InsulationMaterials or combinations of materials such as siliconeelastomer, mica, glass fiber, etc., with suitable bondingsubstances such as appropriate silicone resins. Othermaterials or combinations of materials may be includedin this class if, by experience or accepted tests, they canbe shown to be capable of operation at 180 oC (356 oF).

4/5.13.6 Insulation for Temperature Above 180 oC(356 oF)Materials or combination of materials which byexperience or accepted tests can be shown to becapable of satisfactory operation at temperature over180 oC (356 oF) will also be considered: supportingbackground experience or report of tests conducted inaccordance with a recognized standard ascertainingtheir suitability for the intended application andtemperature operation are to be submitted for review.

4/5.15 Degree of Protection for Enclosure

The designation to indicate the degree of protectionconsists of the characteristic letters IP followed by twonumerals (the "characteristic numerals") indicatingconformity with conditions stated in Tables 4/5.2 and4/5.3. The test and inspection for determining thedegree of protection may be carried out in accordancewith IEC Publication 529 by the manufacturer whosecertificate of tests will be acceptable and is to besubmitted upon request from the Bureau. Type ofenclosure required for protection of equipment is to besuitable for the intended location. See 4/5B2.1.1 forselection of protective enclosure for electricalequipment based on location condition. Equipment incompliance with recognized national standards willalso be considered.

4/5.17 Temperature RatingsWith the exception of equipment associated withcontrol and monitoring systems described in 4/11, inthe following requirements an ambient temperature of40 oC (104 oF) has been assumed for locations outsideof boiler and engine rooms while 45 oC (113 oF) hasbeen assumed as the ambient temperature for the latterspaces; however, electric rotating machines in boilerand engine rooms are to be rated for an ambienttemperature of 50 oC (122 oF). Where the ambienttemperature is in excess of these values, theequipment's total rated temperature is not to beexceeded. Where equipment has been rated on ambient


temperatures less than those contemplated,consideration will be given to the use of suchequipment, provided the total temperature for which theequipment is rated will not be exceeded. For equipmentassociated with control and monitoring systemsdescribed in 4/11, refer to 4/11.3.7e2.

4/5.19 Clearances and Creepage Distances

The distances between live parts of different potentialand between live parts and the case or other earthedmetal, whether across surfaces or in air, are to beadequate for working voltage having regard to thenature of the insulating material and the conditions ofservice. See 4/5C4.11.6 and 4/5D1.1.4 for additionalrequirements for switchboard and high voltage systems.

4/5.21 Service Trial

4/5.21.1 Electrical Installation for Craft ServicesAll auxiliary apparatus is to be tried under workingconditions. Each generator is to be run for a time

sufficient to show satisfactory operation, and paralleloperation with all possible combinations is to bedemonstrated. Each auxiliary motor necessary to theoperation of the craft is to be run for a time sufficient toshow satisfactory performance at such load as canreadily be obtained. All main switches and circuitbreakers are to be operated but not necessarily at fullload. The operation of the lighting system, heaters, etc.,is to be demonstrated satisfactorily. The entireinstallation is to operate to the satisfaction of theSurveyor and the drop in voltage on any part of theinstallation is not to exceed 6 %. See 4/5B3.1.3.

4/5.21.2 Communication FacilitiesSatisfactory operation of the interior communicationssystem required by 4/5A8 is to be demonstrated to theSurveyor during sea trials. Particular attention is to begiven to demonstrating that the voice communicationsystems required by 4/5A8 provide the capability ofcarrying on a conversation while the craft is beingnavigated.


TABLE 4/5.1 Voltage & Frequency Variations[See 4/5.9]

Quantity in PermanentOperation Variation

Frequency ± 5 %Voltage + 6 %, - 10 %

TABLE 4/5.2 Degree of Protection- indicated by the first characteristic numeral[See 4/5.15]

Degree of Protection

FirstCharacteristic

Numeral

Short Description Definition

0

1

2

3

4

5

6

Non - protected

Protected against solidobjects greater than 50 mm (2in.)

Protected against solidobjects greater than 12 mm(0.5 in.)

Protected against solidobjects greater than 2.5 mm(0.1 in.)

Protected against solidobjects greater than 1 mm(0.04 in.)

Dust protected

Dust-tight

No special protection

A large surface of the body, such as a hand (but noprotection against deliberate access). Solid objectexceeding 50 mm (2 in.) in diameter.

Fingers or similar objects not exceeding 80 mm (3.15 in.) inlength. Solid objects exceeding 12 mm (0.5 in.) in diameter.

Tools, wires, etc. of diameter or thickness greater than 2.5mm (0.1 in.). Solid objects exceeding 2.5 mm (0.1 in.) indiameter

Wires or strips of thickness greater than 1 mm (0.04 in.).Solid objects exceeding 1 mm (0.04 in.) in diameter.

Ingress of dust is not totally prevented, but dust does notenter in sufficient quantity to interfere with satisfactoryoperation of the equipment

No ingress of dust

[Designation]The degree of protection is designated as shown in the following examples:When it is required to indicate the degree of protection by only one characteristic numeral which shows either degree ofprotection against foreign bodies and electrical shock or against liquid, the omitted numeral is to be replaced by the letter X. Examples:

(1) IP56 The first characteristic numeral of "5".The second characteristic numeral of "6".


TABLE 4/5.2 Degree of Protection(continued) - indicated by the first characteristic numeral

[See 4/5.15]

(2) IPX5 Degree of protection against only liquid.(3) IP2X Degree of protection against only foreign bodies and electrical shock.

TABLE 4/5.3 Degree of Protection- indicated by the second characteristic numeral[See 4/5.15]

Degree of Protection

SecondCharacteristic

Numeral

ShortDescription

Definition

0

1

2

3

4

5

6

7

8

Non - protected

Protected against drippingwater

Protected against drippingwater when tilted up to 15deg.

Protected against sprayingwater

Protected against splashingwater

Protected against water jets

Protected against heavy seas

Protected against the effectsof immersion

Protected against submersion

No special protection.

Dripping water (vertically falling drops) is to have noharmful effect.

Vertically dripping water is to have no harmful effect whenthe enclosure is tilted at any angle up to 15 deg. from itsnormal position.

Water falling as spray at an angle up to 60 deg. from thevertical is to have no harmful effect.

Water splashed against the enclosure from any direction isto have no harmful effect.

Water projected by a nozzle against the enclosure from anydirection is to have no harmful effect.

Water from heavy seas or water projected in powerful jetsis not to enter the enclosure in harmful quantities.

Ingress of water in a harmful quantity is not to be possiblewhen the enclosure is immersed in water under definedconditions of pressure and time.

The equipment is suitable for continuous submersion inwater under conditions which are to be specified by themanufacturer.

Note.- Normally this will mean that the equipment ishermetically sealed. However, with certain types ofequipment, it can mean that water can enter but only in sucha manner that it produces no harmful effects.

See Designation & examples in Table 4/5.2.

PART 4 SECTION 5|7 Electrical Installations -- Part A. Systems

Part A. Systems

4/5A1 Plans and Data to be Submitted

4/5A1.1 Wiring

4/5A1.1.1 SystemsOne line diagrams for the following electrical systemsare to be submitted for review.

- Power Supply and Distribution- Lighting including Navigation Light- Internal Communication- General Emergency Alarm- Fire Detection and Alarm- Steering Gear Control- Intrinsically-safe Equipment- Emergency Generator Starting

4/5A1.1.2 Data for Wiring SystemsThe one line diagrams are to show the circuitdesignation, type and size of cables, cable grouping andbanking, trip setting and rating of the circuit protectiondevices, the location of electrical equipmentaccompanied by list of components, complete feederlist, rated load current for each branch circuit. The oneline diagram for power supply and distribution systemsis to indicate the following components details.

Note:For craft having a length of 61 m (200 ft) and over, a voltagedrop calculation for the longest run of each cable size is to beincluded.

Generator: kW or kVA rating, voltage, ratedcurrent, frequency, number ofphases, power factor

Batteries: type, voltage, capacity, conductorprotection (when required)

Motors: kW rating, remote stops (whenrequired)

Transformers: kVA rating, rated voltage andcurrent on primary and secondaryside, connection method

The one line diagram for power supply and distributionsystems is also to include a list of sequential start ofmotors and equipment having emergency tripping orpreferential tripping features.

4/5A1.3 Short-circuit Data

In order to establish that the protective devices on themain and emergency switchboards have sufficientshort-circuit breaking and making capacities, data areto be submitted giving the maximum calculated short-circuit current in symmetrical r.m.s. and asymmetricalpeak values available at the main bus bars together with

the maximum allowable breaking and makingcapacities of the protective device. Similar calculationsare to be made at other points in the distribution systemwhere necessary to determine the adequacy of theinterrupting capacities of protective devices.

4/5A1.5 Protective Device Coordination

A protective device coordination study is be submittedfor review. This protective device coordination studyis to consist of an organized time-current study of allprotective devices in series from the utilizationequipment to the source for all circuit protectiondevices having different setting or time-currentcharacteristics for long-time delay tripping, short-timedelay tripping, and instantaneous tripping, whereapplicable. Where an overcurrent relay is provided inseries and adjacent to the circuit protection device, theoperating and time-current characteristics of the relayare to be considered for coordination. See 4/5A5.1.5.

4/5A1.7 Load Analysis

An electric-plant load analysis is to be submitted forreview. The electric-plant load analysis is to cover alloperating conditions of the craft, such as normal seagoing, harbor in/out, and emergency operations.

4/5A2 Craft Service Main Source of Power

4/5A2.1 Power Supply by Generator

4/5A2.1.1 Number of GeneratorsCraft using electricity for craft's service power or lightare to be provided with at least two electric generatorsfor the craft service electrical demand.

4/5A2.1.2 Capacity of GeneratorsThe capacity of the generating sets is to be such that inthe event of any one generating set being stopped it willstill be possible without recourse to the emergencysource of power to supply those services necessary toprovide normal operational conditions of propulsionand safety, preservation of the cargo and minimumcomfortable conditions of habitability which are toinclude at least adequate services for cooking, heating,domestic refrigeration, mechanical ventilation, sanitaryand fresh water.

4/5A2.1.3 Starting from Dead Craft ConditionThe generating sets are to be such that with any onegenerator or its primary source of power out ofoperation, the remaining generating sets are capable ofproviding the electrical services necessary to start themain propulsion plant from a dead craft condition. Theemergency source of electrical power may be used forthe purpose of starting from a dead craft condition if its


capability either alone or combined with that of anyother source of electrical power is sufficient to provideat the same time those services required to be suppliedby 4/5A3.3.2 to 4/5A3.3.3.

4/5A2.1.4 Power Supplied by Propulsion GeneratorFor craft propelled by electric power and having two ormore constant voltage propulsion generators, the craft'sservice electric power may be derived from this sourceand additional craft's service generators need not befitted provided that with one propulsion generator outof service, a speed of 7 knots or one-half of the designspeed whichever is the lesser can be maintained. See4/5D2.17.4 to 4/5D2.17.6 for details of propulsiongenerator.

4/5A2.1.5 Fuel Capacity for Generator PrimeMoverWhere the fuel for any craft's service generator primemover differs from the fuel for the main propulsionplant, adequate fuel capacity for that craft's servicegenerator prime mover with adequate margins is to beprovided for the longest anticipated run of the craftbetween fueling ports.

4/5A2.3 Generator Driven by Propulsion Unit

4/5A2.3.1 Shaft Generator as a Main Source ofPowerA generator driven by a main propulsion unit (shaftgenerator) which is intended to operate at a constantspeed, e.g. a system where craft speed and direction arecontrolled only by varying propeller pitch, may beconsidered to be one of the generators required by4/5A2.1.1.

4/5A2.3.2 Non-constant Speed Shaft GeneratorShaft generator installations which do not comply withthe criteria in 4/5A2.3.1 may be fitted in addition to theabove required generators provided that an alternativesource of electrical power can be brought on lineautomatically within 45 seconds whenever the voltageor frequency of the shaft generator deviates, for anyreason, beyond the prescribed limits.

4/5A2.5 Sizing of A.C. Generator

In selecting the capacity of an alternating-currentgenerating plant, particular attention is to be given tothe starting current of motors forming part of thesystem. Under normal sea going condition of the craftwith one generator held in reserve as a standby, theremaining generator sets operating in parallel andinitially carrying minimum load necessary for operatingthe craft are to have sufficient capacity with respect tothe largest idle motor on the craft so that the motor canbe started and the voltage drop occasioned by its

starting current will not cause any already runningmotor to stall or control equipment to drop out.

4/5A3 Emergency Source of Power

4/5A3.1 General

A self-contained emergency source of electrical poweris to be provided.

4/5A3.1.1 LocationThe emergency source of electrical power, associatedpower transformer, if any, transitional source ofemergency power, emergency switchboard, emergencylighting switchboard, and the fuel oil tank foremergency generator prime mover are to be locatedabove the waterline in the final condition of damage asreferred to in Section 3/3 (see also 4/1.21), outside themachinery casing, and are to be readily accessible fromthe open deck. They are not to be located forward ofthe collision bulkhead.

4/5A3.1.2 Separationa Machinery Space of Category A The location of

the emergency source of electrical power, associatedpower transformer, if any, the transitional source ofemergency power, the emergency switchboard and theemergency lighting switchboard in relation to the mainsource of electrical power, associated transformingequipment, if any, and the main switchboard is to besuch that a fire or other casualty in the space containingthe main source of electrical power, power transformer,if any, and the main switchboard, or in any machineryspace of category A will not interfere with the supply,control and distribution of emergency electrical power.As far as practicable the space containing theemergency source of electrical power, associatedtransforming equipment, if any, the transitional sourceof emergency electrical power and the emergencyswitchboard including trunks to such spaces are not tobe contiguous to the boundaries of machinery spaces ofcategory A or those spaces containing the main sourceof electrical power, associated transforming equipment,if any, and the main switchboard.

b Machinery Space Other Than Category ASpaces containing emergency sources of power are tobe separated from machinery spaces (as defined in4/1.17.2) other than Category A machinery spaces, by aboundary insulated to a level of not less than A-15 forbulkheads and decks and A-0 for the overhead fromany such space (including trunks to such spaces).Where the emergency sources of power is a generatorthe above is not intended to preclude the location of theemergency generator in the same space as its primemover regardless of size.


c Alternative Arrangement Where it can beshown that the arrangements of the spaces containingthe emergency source of power in relation to machineryspace of category A are in compliance with therequirements of the governmental authority of thecountry whose flag the craft flies, either of thefollowing may be considered in lieu of 4/5A3.1.2a:

1 Contiguous boundaries insulated to A-60 withthe insulation extending at least 450 mm (18in.) beyond the boundary of the spacecontaining the emergency source of power.

2 Separation by a cofferdam having dimensionsas required for ready access and extending atleast 150 mm (6 in.) beyond the boundaries ofthe space containing the emergency source ofpower. Except for cables feeding serviceslocated in the machinery space or thosespaces containing main source of electricalpower, associated transformer or converter, ifany, and main switchboard, emergencyelectric cables are not to be installed in suchcofferdams unless the cofferdam is insulatedto A-60.

4/5A3.1.3 Alternative to Emergency Source ofPowerWhere the main source of electrical power is located intwo or more compartments which are not contiguous,each of which has its own self-contained systems,including power distribution and control systems,completely independent of each other and such that afire or other casualty in any one of the spaces will notaffect the power distribution from the others, or to theservices required by 4/5A3.3, the requirements of4/5A3.1, 4/5A3.1.1 and 4/5A3.5.4 may be consideredsatisfied without an additional emergency source ofelectrical power, provided that:

a There is at least one generating set, meeting therequirements of Table 4/1.1 and each of sufficientcapacity to meet the requirements of 4/5A3.3, in eachof at least two non-contiguous spaces;

b The arrangements required by a in each suchspace are equivalent to those required by 4/5A3.5.2,4/5A3.9 and 4/5A3.15 so that a source of electricalpower is available at all times to the services requiredby 4/5A3, and

c The generator sets referred to in a and their self-contained systems are installed in accordance with4/5A3.1.1.

4/5A3.3 Emergency Services

4/5A3.3.1 GeneralThe electrical power available is to be sufficient tosupply all those services that are essential for safety inan emergency, due regard being paid to such servicesas may have to be operated simultaneously and forequipment which can be shown as not being required in

actual service to draw their rated loads. In the lattercase supporting details are to be submitted. Theemergency source of electrical power is to be capable,having regard to starting currents and the transitorynature of certain loads, of supplying simultaneously atleast the following services for the period specified in

4/5A3.3.2 to 4/5A3.3.10, if they depend upon anelectrical source for their operation.

4/5A3.3.2 Lighting Systems and Navigation Lighta Emergency Lighting for 12 hours

1 At the stowage positions of life-savingappliances;

2 At all escape routes such as alleyways,stairways, exits from accommodation andservice spaces, embarkation points, etc.;

3 In the public spaces, if any;4 In the machinery spaces and main emergency

generating spaces, including their controlpositions;

5 In control stations;6 At the stowage positions for fireman' s outfits,

and7 At the steering gear.

b For period of 12 hours:Navigation lights and other lights required bythe International Regulation for PreventingCollisions at Sea in force.

4/5A3.3.3 Communication System, Radio,Navigation Aid, and Fire Alarm Systems and FireExtinguishing Remote ControlsFor a period of 12 hours:

a Electrical internal communication equipment forannouncements during evacuation;

b The navigational equipment as required byChapter 13 of the IMO International Code of Safety forHigh-speed Craft. Where such provision isunreasonable or impracticable, the Administration maywaive this requirement for craft of less than 5,000 GT;

c Fire-detection and general alarm system andmanual fire alarms;

d Remote control devices of fire-extinguishingsystems, if electrical, and

e Craft radio facilities and other loads as set out in14.12.2 of the IMO International Code of Safety forHigh-speed Craft.

4/5A3.3.4 Emergency Fire PumpFor period of 12 hours, one of the fire pumps requiredby 4/9.15.2 if dependent upon the emergency generatorfor its source of power.

4/5A3.3.5 Steering GearSteering gear to comply with 4/5A6.5 if powered fromthe emergency source , for a period of 10 minutescontinuous operation.


4/5A3.3.6 Emergency Control and MonitoringSystemsEmergency control monitoring systems as required by4/11.3.6a2.

4/5A3.3.7 Emergency Sprinkler and DrencherPumpFor period of 12 hours, the sprinkler pump anddrencher pump, if fitted.

4/5A3.3.8 Emergency Bilge Pump and ControlsFor period of 12 hours, the emergency bilge pump andall the equipment essential for the operation ofelectrically powered remote controlled bilge valves.

4/5A3.3.9 Signaling Lamps and WhistleFor a period of 4 hours of intermittent operation:

a The daylight signaling lamps, if they have noindependent supply from their own accumulatorbattery, and

b The craft's whistle, if electrically driven.

4/5A3.3.10 Craft on Short Duration VoyagesIn a craft engaged regularly in voyages of shortduration, where an adequate standard of safety isattained, a lesser period than the 18 hour periodspecified in 4/5A3.3.2a, 4/5A3.3.2b, 4/5A3.3.3, and

4/5A3.3.4 but not less than 5.

4/5A3.5 Power Supply

4/5A3.5.1 GeneralThe emergency source of electrical power may beeither a generator or an accumulator battery inaccordance with 4/5A3.5.2 or 4/5A3.5.3 below:

4/5A3.5.2 GeneratorWhere the emergency source of electrical power is agenerator, it is to be:

a Driven by a prime mover with an independentsupply of fuel, having a flashpoint (closed cup test) of

not less than 43 oC (110 oF)*, and

* Fuel with a lower flashpoint, but not lower than 35°C, may beused in gas turbines only subject to compliance with theprovisions specified in 4/3.9.

b 1) Started automatically upon failure of the mainsource of electrical power supply andconnected automatically to the emergencyswitchboard - then, those services referred toin 4/5A3.7 are to be connected automaticallyto the emergency generator as quickly as issafe and practicable subject to a maximum of45 seconds, or

2) Provided with a transitional source ofemergency electrical power as specified in4/5A3.7 unless an emergency generator isprovided capable both of supplying theservices referred to in 4/5A3.7 of beingautomatically started and supplying therequired load as quickly as is safe andpracticable subject to a maximum of 45seconds, and

c An adequate fuel capacity for the emergencygenerator prime mover is to be provided.

4/5A3.5.3 Accumulator BatteryWhere the emergency source of electrical power is anaccumulator battery it is to be capable of:

a Carrying the emergency electrical load withoutrecharging while maintaining the voltage of the batterythroughout the discharge period within 12% above orbelow its nominal voltage;

b Automatically connecting to the emergencyswitchboard in the event of failure of the main sourceof electrical power, and

c Immediately supplying at least those servicesspecified in 4/5A3.7.

4/5A3.5.4 Emergency Generator for Non-emergency ServicesProvided that suitable measures are taken forsafeguarding independent emergency operation underall circumstances, the emergency generator may beused, exceptionally, and for short periods, to supplynon-emergency circuits during blackout situation, deadcraft situation and routine use for testing. See also4/5A3.9.5.

4/5A3.7 Transitional Source of Power

The transitional source of emergency electrical powerwhere required by 4/5A3.5.2.b2 is to consist of anaccumulator battery which is to operate withoutrecharging while maintaining the voltage of the batterythroughout the discharge period within 12% above orbelow its nominal voltage and be of sufficient capacityand is to be so arranged as to supply automatically inthe event of failure of either the main or the emergencysource of electrical power at least the followingservices if they depend upon an electrical source fortheir operation:

1 For a period of half an hour, the lighting requiredby 4/5A3.3.2. For this transitional phase, the requiredemergency electric lighting, in respect of the machineryspace and accommodation and service spaces may beprovided by permanently fixed, individual,automatically charged, relay operated accumulatorlamps, and

2 All services required by 4/5A3.3.3a through4/5A3.3.3d and 4/5A3.3.9.


3 With respect to the watertight doors:a Power to operate the watertight doors, but not

necessarily simultaneously, unless anindependent temporary source of storedenergy is provided. The power sourceshould have sufficient capacity to operateeach door at least three times, i.e. closed -open - closed, against an adverse list of 15°,and

b Power to the control, indication and alarmcircuits for the watertight doors for half anhour.

4/5A3.9 Emergency Switchboard

4/5A3.9.1 GeneralThe emergency switchboard is to be installed as near asis practicable to the emergency source of electricalpower.

4/5A3.9.2 Emergency Switchboard for GeneratorWhere the emergency source of electrical power is agenerator, the emergency switchboard is to be locatedin the same space unless the operation of theemergency switchboard would thereby be impaired.

4/5A3.9.3 Accumulator BatteryNo accumulator battery fitted in accordance with4/5A3.5.3 or 4/5A3.7 is to be installed in the samespace as the emergency switchboard. An indicator is tobe mounted on the main switchboard or in themachinery control room to indicate when thesebatteries are being discharged.

4/5A3.9.4 Interconnector Feeder BetweenEmergency and Main SwitchboardsThe emergency switchboard is to be supplied duringnormal operation from the main switchboard by aninterconnector feeder which is to be protected at themain switchboard against overload and short circuit.The interconnector feeder is to be disconnectedautomatically at the emergency switchboard uponfailure of the main source of electrical power. Wherethe system is arranged for feedback operation, theinterconnector feeder is also to be protected at theemergency switchboard against short circuit. Inaddition, the circuit protection device at the emergencyswitchboard on the interconnector feeder is to trip toprevent overloading of the emergency generator.

4/5A3.9.5 Disconnection of Non-emergency CircuitsFor ready availability of the emergency source ofelectrical power, arrangements are to be made wherenecessary to disconnect automatically non-emergencycircuits from the emergency switchboard so thatelectrical power is to be available automatically to theemergency circuits.

4/5A3.11 Arrangements for Periodic Testing

Provision is to be made to enable the periodic testing ofthe complete emergency system and is to include thetesting of automatic starting arrangements.

4/5A3.13 Craft Intended to Carry Passengers

See 5/1.13.

4/5A3.15 Starting Arrangements for EmergencyGenerator Sets

4/5A3.15.1 Cold ConditionsEmergency generating sets are to be capable of beingreadily started in their cold condition at a temperatureof 0 oC (32 oF). If this is impracticable, or if lowertemperatures are likely to be encountered, heatingarrangements are to be provided for ready starting ofthe generating sets.

4/5A3.15.2 Number of StartsEach emergency generator that is arranged to beautomatically started is to be equipped with approvedstarting devices with a stored energy capability of atleast three consecutive starts. Unless a secondindependent means of starting is provided, the sourceof stored energy is to be protected to preclude criticaldepletion by automatic starting system, i.e., theautomatic starting system is only allowable forconsumption of the stored energy source to a level thatwould still provide the capability for starting theemergency generator upon intervention by a personnel.In addition, a second source of energy is to be providedfor an additional three starts within 30 minutes unlessmanual starting can be demonstrated to be effective tothe Surveyor.

4/5A3.15.3 Charging of Stored EnergyThe stored energy is to be maintained at all times, asfollows:

a Electrical and hydraulic starting systems are to bemaintained from the emergency switchboard;

b Compressed air starting systems may bemaintained by the main or auxiliary compressed airreceivers through a suitable non-return valve or by anemergency air compressor which, if electrically driven,is supplied from the emergency switchboard;

c All of these starting, charging and energy storingdevices are to be located in the emergency generatorspace; these devices are not to be used for any purposeother than the operation of the emergency generatingset. This does not preclude the supply to the airreceiver of the emergency generating set from the mainor auxiliary compressed air system through the non-return valve fitted in the emergency generator space.


4/5A3.15.4 Manual StartingWhere automatic starting is not required as per4/5A3.5.2b2, manual (hand) starting is permissible,such as manual cranking, inertia starters, manuallycharged hydraulic accumulators, or power chargecartridges, where they can be demonstrated as beingeffective to the Surveyor.When manual (hand) starting is not practicable, therequirements of 4/5A3.15.2 and 4/5A3.15.3 are to becomplied with except that starting may be manuallyinitiated.

4/5A3.17 Cargo Craft Less Than 500 GT HavingElectrical Plants of 75 kW and Above

4/5A3.17.1 GeneralThese requirements are intended for cargo craft lessthan 500 GT having electrical plants of an aggregatecapacity of 75 kW and above. The emergency sourceof electrical power is to be self-contained and readilyavailable. 4/5A3.1.1, 4/5A3.1.2, 4/5A3.5 through4/5A3.13 and 4/5A3.19 are also applicable. Where thesource of electrical power is a battery, see 4/5B2.7 forthe installation. For emergency lighting, a relay-controlled, battery-operated lanterns is acceptable.

4/5A3.17.2 CapacityThe emergency source of electrical power is to becapable of supplying simultaneously at least thefollowing services for the period as specified herein:

a Emergency lighting for 6 hours for:1 At the stowage positions of life-saving

appliances;2 At all escape routes such as alleyways,

stairways, exits from accommodation andservice spaces, embarkation points, etc.;

3 In the public spaces, if any;4 In the machinery spaces and main emergency

generating spaces, including their controlpositions;

5 In control stations;6 At the stowage positions for fireman' s outfits,

and7 At the steering gear;

b Navigation lights and other lights required by theInternational Regulation for Preventing Collisions atSea in force.

c For 6 hours, craft radio facilities and other loadsas set out in 14.12.2 of the IMO International Code ofSafety for High-speed Craft.

d For 6 hours, electrical internal communicationequipment for announcements during evacuation.

4/5A3.19 Requirements by the GovernmentalAuthority

Attention is directed to the requirements of thegovernmental authority of the country, whose flag thecraft flies, for the emergency services and theaccumulator batteries required in various types ofcraft.

4/5A4 Distribution System

4/5A4.1 Craft Service Distribution System

4/5A4.1.1 GeneralCurrent-carrying parts with potential to earth are to beprotected against accidental contact.For recognized standard distribution systems, see 4/5.7.Separate feeders are to be provided for essential andemergency services.During normal operation these consumers may beconnected to the same power-bus directly or viadistribution boards or group starters, but should beseparated by removable links or other approved means.Each power-bus should be able to supply all equipmentnecessary to maintain the control of propulsion,steering control, navigation, lighting and ventilation,and allow starting of the largest essential electric motorat any load. See 4/5C15.2.Where loss of a particular essential service would causeserious risk to the craft, the service should be fed by atleast two independent circuits fed in such a way that nosingle failure in the electrical supply or distributionsystems would effect both supplies.For cargo craft, in order to minimize the probability ofcompromising the craft’s safety due to failure of anessential service, partial reduction in the capabilityfrom normal operation may be accepted; additionally,non-duplicated consumers of essential servicesconnected to the emergency switchboard directly or viadistribution boards may be accepted.Automatic load-dependent disconnection of non-essential consumers may be allowed.

4/5A4.1.2 Method of DistributionThe output of the craft's service generators may besupplied to the current consumers by way of eitherbranch system, meshed network system, or ring mainsystem. The cables of a ring-main or other loopedcircuit (e.g. interconnecting section boards in acontinuous circuit) are to be formed of conductorshaving sufficient current-carrying and short-circuitcapacity for any possible load and supplyconfiguration.


Distribution systems should be so arranged that thefeeders from the main and emergency sources areseparated both vertically and horizontally as widely aspracticable.

4/5A4.1.3 Through-feed ArrangementsThe size of feeder conductors is to be uniform for thetotal length, but may be reduced beyond anyintermediate section board and distribution board,provided that the reduced size section of the feeder isprotected by an overload device.

4/5A4.1.4 Motor Control CenterFeeder cables from the main switchboard or any sectionboard to the motor control centers are to have acontinuous current-carrying capacity not less than100% of the sum of the nameplate ratings of all themotors supplied. The over-current protective device isto be in accordance with 4/5A5.1.3.

4/5A4.1.5 Motor Branch CircuitA separate circuit is to be provided for each fixedmotor having a full-load current rating of 6 amperes ormore and the conductors are to have a carrying capacityof not less than 100% of the motor full-load currentrating. No branch circuit is to have conductors less than1.5 mm2 wire. Circuit-disconnecting devices are to beprovided for each motor branch circuit and to be inaccordance with 4/5B2.13.2 and 4/5C4.17.2.

4/5A4.1.6 Power Supply Through Transformersand Converters

a Continuity of Supply Where transformers orconverters are an essential part of the propulsion orcraft service electrical supply system, the system is tobe so arranged as to ensure at least the same continuityof the supply as required by 4/5A2.1.2 for generators.

b Arrangements Each required transformer is tobe located as a separate unit with separate enclosure orequivalent, and is to be served by separate circuits onthe primary and secondary sides. Each of the secondarycircuits is to be provided with a multipole isolatingswitch. A circuit breaker provided in the secondarycircuit in accordance with 4/5A5.15.1 will beacceptable in lieu of multipole isolating switch.

4/5A4.1.7 Ventilation SystemVentilation fans for cargo space are to have feedersseparate from those for accommodations.

4/5A4.1.8 Heating AppliancesEach heater is to be connected to a separate finalsubcircuit. However, a group of up to 10 heaters whosetotal current does not exceed 16 A may be connected toa single final subcircuit.

4/5A4.1.9 Circuits for Bunker or Cargo SpaceAll lighting and power circuits terminating in a bunkeror cargo space are to be provided with a multiple poleswitch outside the space for disconnecting suchcircuits.

4/5A4.3 Hull Return System

4/5A4.3.1 GeneralThe hull return system is not to be used for power,heating, or lighting except that the following systemsmay be used:

1 impressed current cathodic protective systems;2 limited and locally earthed systems, provided

that any possible resulting current does notflow directly through any hazardous areas, or

3 insulation level monitoring devices, providedthe circulation current does not exceed 30 mAunder all possible conditions.

Current-carrying parts with potential to earth are to beprotected against accidental contact.

4/5A4.3.2 Final Subcircuits and Earth WiresWhere the hull return system is used, all finalsubcircuits, i.e., all circuits fitted after the lastprotective device, are to consist of two insulated wires,the hull return being achieved by connecting to the hullone of the busbars of the distribution board from whichthey originate. The earth wires are to be in accessiblelocations to permit their ready examination and toenable their disconnection for testing of insulation.

4/5A4.5 Earthed Distribution Systems

System earthing is to be effected by means independentof any earthing arrangements of the non-current-carrying parts. Means of disconnection is to beprovided in the neutral earthing connection of eachgenerator so that the generator may be disconnected formaintenance. In distribution systems with neutralearthed or for generators intended to be run withneutrals interconnected, the machines are to bedesigned to avoid circulating currents exceeding theprescribed value. Transformer neutral is not to beearthed unless all corresponding generator neutrals aredisconnected from the system (e.g. during shoresupply).

4/5A4.7 External or Shore Power SupplyConnection

4/5A4.7.1 GeneralWhere arrangements are made for the supply ofelectricity from a source on shore or other externalsource, a termination point is to be provided on thecraft for the reception of the flexible cable from theexternal source. Fixed cables of adequate rating are tobe provided between the termination point and the main


or emergency switchboard. Means for disconnectingthe external or shore power supply are to be providedat the receiving switchboard. See 4/5A5.11 for theprotection of external or shore power supply circuit.

4/5A4.7.2 Earthing TerminalAn earth terminal is to be provided for connecting thehull to an external earth.

4/5A4.7.3 IndicatorsThe external supply connection or shore connection isto be provided with a pilot lamp and a voltmeter (andfrequency meter for A.C.) at main or emergencyswitchboard to show energized status of the cable.

4/5A4.7.4 Polarity or Phase SequenceMeans are to be provided for checking the polarity (forD.C.) or the phase sequence (for three-phase A.C.) ofthe incoming supply in relation to the craft's system.

4/5A4.7.5 Information PlateAn information plate is to be provided at or near theconnection box giving full information on the system ofsupply and the nominal voltage (and frequency if A.C.)of the craft's system and the recommended procedurefor carrying out the connection.

4/5A4.7.6 Securing of Trailing CableProvision is to be made for securing the trailing cableto a framework to absorb stress on the electricalterminals by catenary tension of the cable.

4/5A5 Circuit Protection System

4/5A5.1 System Design

4/5A5.1.1 GeneralElectrical installations are to be protected againstaccidental overload, including short circuit, byautomatic protective devices for :

a Continued supply to remaining essential circuitsin the event of a fault.

b Minimizing the possibility of damage to thesystem and fire.Three-phase, three-wire alternating current circuits areto be protected by a triple-pole circuit breaker withthree overload trips or by a triple-pole switch with afuse in each phase. All branch circuits are to beprotected at distribution boards only and any reductionin conductor sizes is to be protected. Dual-voltagesystems having a earthed neutral are not to have fusesin the neutral conductor, but a circuit breaker whichsimultaneously opens all conductors may be installedwhen desired. In no case is the dual-voltage system toextend beyond the last distribution board.

Additionally, when a protective device is a fuse, it is tobe placed on the load side of the disconnect switchserving the protected circuit.

4/5A5.1.2 Protection Against Short-circuita Protective Devices Protection against short-

circuit is to be provided for each non-earthed conductorby means of circuit breakers or fuses.

b Rated Short-circuit Breaking Capacity Therated short-circuit breaking capacity of every protectivedevice is not to be less than the maximum availablefault current at that point. For alternating current(A.C.), the rated short-circuit breaking capacity is notto be less than the root mean square (r.m.s.) value ofthe A.C. component of the prospective short-circuitcurrent at the point of application. The circuit breakeris to be able to break any current having an A.C.component not exceeding its rated breaking capacity,whatever the inherent direct current (D.C.) componentmay be at the beginning of the interruption.

c Rated Short-circuit Making Capacity The ratedshort-circuit making capacity of every switching deviceis to be adequate for maximum peak value of theprospective short-circuit current at the point ofinstallation. The circuit breaker is to be able to makethe current corresponding to its making capacitywithout opening within a time corresponding to themaximum time delay required.

4/5A5.1.3 Protection Against Overloada Circuit Breakers Circuit breakers or other

mechanical switching devices for overload protectionare to have a tripping characteristics (overload-triptime) adequate for the overload capacity of all elementsin the system to be protected and for any discriminationrequirements.

b Fuses The fuse of greater than 320 amperes isnot to be used for overload protection.

c Rating Fuse ratings and rating (or settings, ifadjustable) of time-delay trip elements of circuitbreakers are not to exceed the rated current capacity ofthe conductor to be protected as listed in Table 4/5C.10except as otherwise permitted for generator, motor, andtransformer circuit protection in 4/5A5.3, 4/5A5.13 and4/5A5.15. If the standard ratings or settings of overloaddevices do not correspond to the rating or the settingallowed for conductors, the next higher standard ratingor setting may be used provided it does not exceed150% of the allowable current carrying capacity of theconductor. Except as otherwise permitted for motor andtransformer branch-circuit protection, adjustable-tripcircuit breakers of the time-delay or instantaneous typeare to be set to operate at not more than 150% of therated capacity of the conductor to be protected.

d Indication The rating or setting of the overloadprotective device for each circuit is to be permanentlyindicated at the location of the protective device.


4/5A5.1.4 Cascade System (Back-up Protection)a General Where a circuit breaker does not have a

short circuit breaking and/or making capacity at leastequal to the maximum prospective short-circuit currentat the point where it is installed, it is to be backed-upby fuse or by a circuit breaker on the generator side,having at least the necessary short-circuit rating for theavailable fault at the point of application. Theupstream circuit breaker or fuse is to be specificallyapproved for back-up combinations with thedownstream circuit breaker and maximum fault ratingfor the combinations is to be provided. Cascadingarrangements exclude generator circuit breakers.

b Application Downstream circuit breakers havingshort circuit ratings less than the short circuit currentavailable at the point of application, will be speciallyconsidered for non-essential circuits and for essentialcircuits where automatic transfer to a duplicate circuitis utilized. The same fuse or circuit breaker may back-up more than one circuit breaker when essentialservices are not involved.

4/5A5.1.5 Coordinated TrippingCoordinated tripping is to be provided betweengenerator, bus tie, bus feeder and feeder protectivedevices. See also 4/5A5.3.2 and 4/5A5.7.1. Except forcascade system (backup protection) in 4/5A5.1.4, thecoordinated tripping is also to be provided betweenfeeder and branch-circuit protective devices foressential services. Continuity of service to essentialcircuits under short-circuit conditions is to be achievedby discrimination of the protective devices as follows:

a The tripping characteristics of protective devicesin series is to be coordinated.

b Only the protective device nearest to the fault isto open the circuit except for cascade system (back-upprotection) as specified in 4/5A5.1.4a.

c The protective devices are to be capable ofcarrying, without opening, a current not less than theshort-circuit current at the point of application for atime corresponding to the opening of the breaker,increased by the time delay required for discrimination.

4/5A5.3 Protection for Generators

4/5A5.3.1 GeneralGenerators of less than 25 kW not arranged for paralleloperation may be protected by fuses. Any generatorsarranged for parallel operation and all generators of 25kW and over are to be protected by a trip-free circuitbreaker whose trip settings are not to exceed thethermal withstand capacity of the generator. The long-time over-current protection is not to exceed 15%above either the full-load rating of continuous-ratedmachines or the overload rating of special-ratedmachines. The shutting down of the prime mover is tocause the tripping of the craft’s service generatorcircuit breaker.

4/5A5.3.2 Trip Setting for CoordinationThe instantaneous and short-time overcurrent trips ofthe generators are to be set at the lowest values ofcurrent and time which will coordinate with the tripsettings of feeder circuit breakers. See also 4/5A5.1.5.

4/5A5.3.3 Load-shedding ArrangementsIn order to safeguard electrical power supply foressential services, load-shedding arrangements todisconnect non-essential services are to be provided inthe following cases.

a Where one generating set is normally used tosupply the required load, but where the possibility exitsthat due to the switching on of additional loads,whether manually or automatically initiated, the totalload exceeds the rated generator capacity.

b Where in case of failure of one of the parallelrunning generators, the total load exceeds theconnected capacity of the remaining generator(s).

4/5A5.3.4 Emergency GeneratorThe emergency generator is also to comply with4/5A5.1, 4/5A5.3, 4/5A5.5 and 4/5A5.7 whereapplicable. See also 4/5A3.9.

4/5A5.5 Protection for Alternating-current (A.C.)Generators

4/5A5.5.1 Short-time Delay TripShort-time delay trip are to be provided with circuitbreakers for A.C. generator. For generators with acapacity of less than 200 kW having prime movers suchas diesel engines or gas turbines which operateindependently of the electrical system, considerationwill be given to omission of short-time delay trips ifinstantaneous and long time delay trips are provided.

4/5A5.5.2 Parallel OperationWhere A.C. generators are arranged for paralleloperation with other A.C. generators, the followingprotective devices are to be provided.

a Instantaneous Trip Instantaneous trips are to beinstalled and set in excess of the maximum short-circuitcontribution of the individual generator where three ormore generators are arranged for parallel operation.

b Reverse Power Protection A time-delayedreverse active power protection or other devices whichprovide adequate protection is to be provided. Thesetting of protective devices is to be in the range 2% to6% of the rated power for turbines and in the range 8%to 15% of the rated power for diesel engines. A fall of50% in the applied voltage is not to render the reversepower protection inoperative, although it may alter thesetting to open the breaker within the above range.

c Undervoltage Protection Means are to beprovided to prevent the generator circuit breaker fromclosing if the generator is not generating, and to openthe same when the generator voltage collapses.


In the case of an undervoltage release provided for thispurpose, the operation is to be instantaneous whenpreventing closure of the breaker, but is to be delayedfor discrimination purposes when tripping a breaker.

4/5A5.7 Protection for Direct Current (D.C.)Generators

4/5A5.7.1 Instantaneous TripD.C. generator circuit breakers are to be provided withan instantaneous trip set below the generator maximumshort-circuit current and are to coordinate with the tripsettings of feeder circuit breakers supplied by thegenerator.

4/5A5.7.2 Parallel Operationa Reverse Current Protection D.C. generators

arranged for parallel operation with other D.C.generators or with an accumulator battery are to beprovided with instantaneous or short-time delayedreverse current protection. The setting of the protectiondevices is to be within the power range specified by4/5A5.5.2b. When the equalizer connection isprovided, the reverse current device is to be connectedon the pole opposite to the equalizer connection wherethe series compound winding for the generator isconnected. Reverse current protection is to be adequateto deal effectively with reverse current conditionsemanating from the distribution system (e.g., electricdriven cargo winches).

b Generator Ammeter Shunts Generator ammetershunts are to be so located that the ammeters indicatetotal generator current.

c Undervoltage Protection Requirements for A.C.generator in 4/5A5.5.2c are also applicable to D.C.generator.

4/5A5.9 Protection for Accumulator Batteries

Accumulator (storage) batteries, other than enginestarting batteries, are to be protected against overloadand short circuits by devices placed as near aspracticable to the batteries but outside of the batteryrooms, lockers or boxes, except that the emergencybatteries supplying essential services are to have shortcircuit protection only. Fuses may be used for theprotection of emergency lighting storage batteriesinstead of circuit breakers up to and including 320amperes rating. The charging equipment, exceptconverters, for all batteries with a voltage more than20% of the line voltage is to be provided with reversecurrent protection.

4/5A5.11 Protection for External or Shore PowerSupply

4/5A5.11.1 GeneralWhere arrangements are made for the supply ofelectricity from a source on shore or other externalsource, permanently fixed cables from the externalsupply or shore connection box to the main oremergency switchboard are to be protected by fuses orcircuit breakers located at the connection box.

4/5A5.11.2 Interlocking ArrangementWhere the generator is not arranged for paralleloperation with the external or shore power supply, aninterlocking arrangement is to be provided for thecircuit breakers or disconnecting devices betweengenerator and the external or shore power supply inorder to safeguard from connecting unlike powersources to the same bus.

4/5A5.13 Protection for Motor Branch Circuits

4/5A5.13.1 GeneralTrip elements of circuit breaker for starting and forshort-circuit protection are to be in accordance with4/5A5.13.2 or 4/5A5.13.3 except that circuit breakershaving only instantaneous trips may be provided as partof the motor control center. Where circuit breakershaving only instantaneous trips are provided, the motorrunning protective device is to open all conductors, andthe motor controller is to be capable of opening thecircuit without damage to itself resulting from a currentup to the setting of the circuit breaker. Circuit-disconnecting devices are to be provided for eachmotor branch circuit and to be in accordance with4/5B2.13.2 and 4/5C4.17.2.

4/5A5.13.2 Direct-current Motor Branch CircuitsThe maximum fuse rating or the setting of the time-delay trip element is to be 150% of the full-load ratingof the motor served. If that rating or setting is notavailable, the next higher available rating or settingmay be used.

4/5A5.13.3 Alternating-current Motor BranchCircuitsThe maximum fuse rating or setting of the trip elementis to be the value stated below. If that rating or settingis not available, the next higher available rating orsetting may be used.


Type of MotorRating or Settingin % Motor Full-

load Current

Squirrel-cage and SynchronousFull-voltage, Reactor or Resistor-starting

250

Autotransformer Starting 200Wound Rotor 150

When fuses are used to protect polyphase motorcircuits, it is to be arranged to protect against single-phasing.The setting of magnetic instantaneous trips for short-circuit protection only is to exceed the transient currentinrush of the motor, and to be the standard valuenearest to, but not less than, 10 times full-load motorcurrent.

4/5A5.13.4 Motor Running ProtectionRunning protection is to be provided for all motorshaving a power rating exceeding 0.5 kW except thatsuch protection is not to be provided for steering gearmotors (see 4/5A6.3). The running protection is to beset between 100% and 125% of the motor rated current.

4/5A5.13.5 Protection for UndervoltageThe motor controller for motors having power ratingexceeding 0.5 kW is to provide protection against lowvoltage. Undervoltage release is to be provided oncontrollers for auxiliaries which are essential to theoperation of the propulsion equipment where theautomatic restart after a voltage failure is nothazardous. Otherwise undervoltage protection is to beused. The use of controllers of the undervoltage releasetype is to be limited to avoid excessive starting currentwhen a group of motors with undervoltage releasecontrollers are restarted automatically upon regainingthe voltage.

4/5A5.15 Protection for Transformer Circuits

4/5A5.15.1 Setting of Overcurrent DeviceEach power and lighting transformer feeder is to beprotected by an overcurrent device rated or set at avalue not more than 125% of rated primary current.When a transformer is provided with an overcurrentdevice in the secondary circuit rated or set at not morethan 125% of rated secondary current, the feederovercurrent device may be rated or set at a value lessthan 250% of the rated primary current.

4/5A5.15.2 Parallel OperationWhen the transformers are arranged for paralleloperation, means are to be provided to disconnect thetransformer from the secondary circuit. Where power

can be fed into secondary windings, short-circuitprotection (i.e., short-time delay trips) is to be providedin the secondary connections.

4/5A5.17 Protection for Meters, Pilot Lamps, andControl Circuits

Indicating and measuring devices are to be protected bymeans of fuses or current limiting devices. For devicessuch as voltage regulators where interruption of thecircuit may have serious consequences, fuses are not tobe used. If fuses are not used, means are to be providedto prevent fire in unprotected part of installation. Fusesare to be placed as near as possible to the tapping fromthe supply.

4/5A6 Systems for Steering Gear

4/5A6.1 Power Supply Feeder

Each electric or electrohydraulic steering gear is to beserved by at least two exclusive circuits fed directlyfrom the main switchboard; however, one of thecircuits may be supplied through the emergencyswitchboard. An auxiliary electric or electrohydraulicsteering gear associated with a main electric orelectrohydraulic steering gear may be connected to oneof the circuits supplying this main steering gear. Thecircuits supplying an electric or electrohydraulicsteering gear are to have adequate rating for supplyingall motors, control systems and instrumentation whichare normally connected to them and operatedsimultaneously. The circuits are to be separatedthroughout their length as widely as is practicable.

4/5A6.3 Protection for Steering Gear Circuit

4/5A6.3.1 Short Circuit ProtectionEach steering gear feeder is to be provided with short-circuit protection which is to be located at the main oremergency switchboard. Long term overcurrentprotection is not to be provided for steering gearmotors.

a Direct Current (D.C.) Motors For D.C. motors,the feeder circuit breaker is to be set to tripinstantaneously at not less than 300% and not morethan 375% of the rated full-load current of the steeringgear motor, except that the feeder circuit breaker on theemergency switchboard may be set to trip at not lessthan 200%.

b Alternating Current (A.C.) Motors For A.C.motors, the protection against excess current, includingstarting current, if provided, is to be for not less thantwice the full load current of the motor or circuit soprotected, and is to be arranged to permit the passageof the appropriate starting currents.


c Fuses as Motor-feeder Protection The use offuses instead of circuit breakers for steering gear motorfeeder short circuit protection is not permitted.

4/5A6.3.2 Undervoltage ReleasePower unit motor controllers and other automatic motorcontrollers are to be fitted with undervoltage release.

4/5A6.5 Emergency Power Supply

Where the rudder stock is required by 3/5.3.1 to beover 230 mm (9 in.) diameter using Ks = 1.0 in way ofthe tiller, excluding strengthening for navigation in ice,an alternative power supply, sufficient at least to supplythe steering gear power unit and also its associatedcontrol system and rudder angle indicator, is to beprovided automatically, within 45 seconds either fromthe emergency source of electrical power or from anindependent source of power located in the steeringgear compartment. The steering gear power unit underalternative power supply is to be capable of moving therudder from 15 degrees on one side to 15 degrees onthe other side in not more than 60 seconds with thecraft at the design draft while running at one half themaximum speed ahead or 7 knots whichever is thegreater. This independent source of power is to be usedonly for this purpose. The alternative power supply isto have a capacity for at least 10 minutes of continuousoperation. See 4/5A3.3.5.

4/5A6.7 Controls, Instrumentation, and Alarms

See 4/8.6.

4/5A7 Lighting and Navigation Light Systems

4/5A7.1 Lighting System

4/5A7.1.1 Main Lighting SystemA main electric lighting system is to provideillumination throughout those parts of the craftnormally accessible to and used by passengers or crew.It is to be supplied from the main source of electricalpower.

4/5A7.1.2 System Arrangementa Main Lighting System The arrangement of the

main electric lighting system is to be such that a fire orother casualty in spaces containing the main source ofelectrical power, associated transforming equipment, ifany, the main switchboard and the main lightingswitchboard, will not render the emergency electriclighting system required by 4/5A3.3.2 of this Sectionor 5/1.13.3a1 or 5/1.13.3b1 inoperative.

b Emergency Lighting System The arrangementof the emergency electric lighting system is to be suchthat a fire or other casualty in spaces containing the

emergency source of electrical power, associatedtransforming equipment, if any, the emergencyswitchboard and the emergency lighting switchboardwill not render the main electric lighting systemrequired by 4/5A7.1.1 inoperative.

4/5A7.1.3 Lighting Circuitsa Machinery Space and Accommodation Space

In spaces such as :

- public spaces;- main machinery spaces;- galleys;- corridors;- stairways leading to boat-decks;

there are to be more than one final sub-circuit forlighting, one of which may be supplied from theemergency switchboard, in such a way that failure ofany one circuit does not leave these spaces in darkness.

b Cargo Spaces Fixed lighting circuits in cargospaces are to be controlled by multipole-linkedswitches situated outside the cargo spaces. Means areto be provided on the multipole linked switches toindicate the live status of circuits.

4/5A7.1.4 Protection for Lighting CircuitsLighting circuits are to be protected against overloadand short circuit. Overload protective devices are to berated or set at not more than 30 amperes. Theconnected load is not to exceed the lesser of the ratedcurrent carrying capacity of the conductor or 80% ofthe overload protective device rating or setting. Thecontrol switches are to be rated for the load controlled.

4/5A7.3 Navigation Light System

4/5A7.3.1 FeedersThe masthead, side and stern lights are to be separatelyconnected to a distribution board reserved fornavigation light, placed in an accessible position onbridge, and is connected directly or throughtransformers to the main or emergency switchboard.These lights are to be fitted with duplicate lamps orother dual light sources and are to be controlled by anindicator panel. Provision is to be made on the bridgefor the navigation lights to be transferred to analternative supply. See 4/5A3.3.2b for power supply.

4/5A7.3.2 Navigation Light IndicatorEach navigation light as listed in 4/5A7.3.1 is to beprovided with an indicator panel which gives audibleand/or visual warning automatically in the event ofextinction of the light. If an audible device is used, it isto be connected to a separate source of supply, forexample a primary or accumulator (storage) battery. Ifa visual signal is used which is connected in series withthe navigation light, means are to be provided to


prevent the extinction of the navigation light due tofailure of the visual signal. A means for disconnectionof each navigation light circuit is to be provided at theindicator panel.

4/5A7.3.3 ProtectionEach navigation light as listed in 4/5A7.3.1 is to beprotected by a fuse in each insulated pole and providedwith a double-pole switch or alternatively by a double-pole circuit breaker fitted on the distribution board orthe indicator panel referred to above. The rating of thefuses is to be at least twice that of the largest branchfuse and greater than the maximum panel load.

4/5A8 Interior Communication Systems

4/5A8.1 Operating Compartment

At least two independent means are to be provided forcommunicating orders from the operating compartmentto the position in the machinery space or in the controlroom from which the speed and direction of thrust ofthe propellers are controlled. Appropriate means ofcommunication are to be provided to any otherpositions from which the main propulsion machinerymay be controlled. See 4/5A3.3.3a for power supply.

4/5A8.3 Voice Communications

4/5A8.3.1 Propulsion and Steering Gear ControlStationsA common talking means of voice communication andcalling is to be provided between the operatingcompartment, main propulsion control station (iffitted), and the steering gear compartment so that thesimultaneous talking among these spaces is possible atall times and the calling to these spaces is alwayspossible even if the line is busy

4/5A8.3.2 ElevatorWhere an elevator is installed, a telephone is to bepermanently installed in all cars and connected to acontinuously manned area. The telephone may besound powered, battery operated or electricallypowered from the emergency source of power.

4/5A8.3.3 Independence of Power Supply CircuitFinal subcircuit for power supply to these voicecommunication systems is to be independent of otherelectrical systems and control, monitoring, and alarmsystems. See 4/5A3.3.3a for power supply.

4/5A8.5 Public Address System

A public address system is to be provided. This systemis to cover all areas where passengers and crew haveaccess, escape route, and places of embarkation into

survival craft. The system should be such that floodingor fire in any compartment does not render other partsof the system inoperable.

4/5A8.7 Emergency and Interior-communicationSwitchboard

Emergency and interior-communication switchboards,when fitted, are to comply with the applicable parts of4/5C4 and attention is directed to the requirements ofthe governmental authority whose flag the craft flies.

4/5A9 Manually Operated Alarms

4/5A9.1 General Emergency Alarm System

Each craft over 100 GT is to be fitted with a generalemergency alarm. The general emergency alarmsystem is to be capable of sounding the generalemergency alarm signal consisting of seven or moreshort blasts followed by one long blast on the craft'swhistle or siren and additionally on an electricallyoperated bell or klaxon or other equivalent warningsystem, which is to be powered from the craft's mainsupply and the emergency source of electrical powerrequired by 4/5A3, as appropriate. The system is becapable of operation from the operating compartmentand, except for the craft's whistle, also from otherstrategic points. The system is to be audible throughoutall the accommodation and normal crew workingspaces and open decks, and its sound pressure level isto be at least 10 dB(A) above ambient noise levelsunder way in normal cruise operation. The alarm is tocontinue to function after it has been triggered until it ismanually turned off or is temporarily interrupted by amessage on the public address system.

4/5A9.3 Engineers' Alarm

An engineer's alarm operable from the main propulsioncontrol station is to be provided on craft of 500 GTand over. It is to be audible in all the accommodationsand if provided, in the engineers' accommodation. See4/5A3.3.9 for power supply.

4/5A9.5 Refrigerated Space Alarm

Fan and diffuser rooms serving subfreezingcompartments are to be provided with a device capableof activating an audible and visual alarm in a mannedcontrol center and operable from within the latter spacefor the protection of personnel. See 4/5A3.3.9 forpower supply.


4/5A9.7 Elevator

A device which will activate an audible and visualalarm in a manned control center is to be provided inall cars. Such alarm system is to be independent ofpower and control systems of the elevator. See4/5A3.3.9 for power supply.

4/5A10 Fire Protection and Fire Detection Systems

4/5A10.1 Emergency Stop

4/5A10.1.1 Ventilation Systema General All electrical ventilation systems are to

be provided with means for stopping the motors in caseof fire or other emergency. These requirements do notapply to closed re-circulating systems within a singlespace. For passenger craft, the ventilation fans of eachzone in the accommodation spaces are to be capable ofbeing independently control from a continuously

manned control station. See also 4/9.5.1.

b Machinery Space Ventilation The mainmachinery-space ventilation is to be provided withmeans for stopping the ventilation fans, which is to belocated in the passageway leading to, but outside of thespace, or in a centralized fire-fighting location.

c Ventilation Other Than Machinery Space Acontrol station for all other ventilation systems is to belocated in a centralized fire-fighting location oroperating compartment, or in an accessible positionleading to, but outside of the space ventilated.

4/5A10.1.2 Fuel Oil UnitsSee 4/6.49.3 and 4/9.5.3 for emergency tripping andemergency stop for fuel oil units.

4/5A10.3 Fire Detection and Alarm System

See 7.7.1 through 7.7.3 and 7.8.3 of the IMOInternational Code of Safety for High-speed Craft and

4/11.3.18c.

PART 4 SECTION 5|21 Electrical Installations -- Part B. Installations

Part B. Installation

4/5B1 Plans and Data to be Submitted

4/5B1.1 Booklet of Standard Details

A booklet of the standard wiring practices and detailsincluding such items as cable supports, earthing details,bulkhead and deck penetrations, cable joints andsealing, cable splicing, watertight and explosion-proofconnections to equipment, earthing and bondingconnections, etc., as applicable, is to be submitted.Where cable penetration methods for A- or B-classdecks or bulkheads are shown, an evidence of approvalby an Administration signatory to 1974 SOLAS asamended is also to be submitted.

4/5B1.3 Arrangement of Electrical Equipment

A general arrangement plan showing the location of atleast the following electrical equipment is to besubmitted for review.

- Generator, Essential Motor, and Transformer- Battery- Switchboard, Battery Charger, and MotorController- Emergency Lighting Fixture- General Emergency Alarm Device and AlarmActuator- Detector, Manual Call Point and Alarm Panel forFire Detection and Alarm System- Certified-safe Type Equipment

Where cable splices or cable junction boxes areprovided, locations of the splices and cable junctionboxes together with the information of their servicesare also to be submitted for review.

4/5B1.5 Electrical Equipment in Hazardous Areas

A plan showing hazardous areas is to be submitted forreview together with the following:

- A list of intended electrical equipment in theindicated hazardous areas, including a descriptionof the equipment, applicable degree of protectionand ratings. See 4/5B7.3.- For intrinsically-safe systems, also wiring plans,installation instructions with any restrictionsimposed by the certification agency.- Detail of installation for echo sounder, speed log,and impressed current cathodic protection systemwhere located in these areas.

When the selection of the equipment has beenfinalized, a list identifying all equipment in thehazardous areas, their degree of protection, rating,manufacturer's name, model number and evidence ofcertification is to be submitted. An approved copy ofthis list/booklet is to be maintained on board for futurereference. See 1/3.3.1k5 and 4/5B7.1.4.

4/5B2 Equipment Installation and Arrangement

4/5B2.1 General Consideration

4/5B2.1.1 Equipment LocationElectrical equipment is to be so placed or protected asto minimize the probability of mechanical injury ordamage from the accumulation of dust, oil vapors,steam or dripping liquids. Equipment liable to generatearc is to be ventilated or placed in a compartmentventilated to avoid accumulation of flammable gases,acid fumes and oil vapors. See Table 4/5B.1 forrequired degree of protection for various locations.

4/5B2.1.2 Protection from Bilge WaterAll generators, motors and electric couplings are to beso arranged that they cannot be damaged by bilgewater; and, if necessary, a watertight coaming is to beprovided to form a well around the base of suchequipment with provision for removing water from thewell.

4/5B2.1.3 AccessibilityThe design and arrangement of electrical apparatus isto provide accessibility to parts requiring inspection oradjustment. Armature and field coils, rotors andrevolving fields are to be removable and where airducts are used, there are to be means of access.

4/5B2.1.4 Special Requirements for Non-metallicCraftThe following is applicable to non-metallic craft.

a In order to minimize the risk of fire, structuraldamage, electrical shock and radio interference due tolightning strike or electrostatic discharge, all metalparts of the craft are to be bonded together, in so far aspossible in consideration of galvanic corrosion betweendissimilar metals, to form a continuous electricalsystem, suitable for the earth return of electricalequipment and to connect the craft to the water whenwaterborne. The bonding of isolated componentsinside the structure is not generally necessary, except infuel tanks. A lightning protection system consisting of acopper spike, a conductor of a minimum cross-sectionper 4/5B2.1.4b and a grounding plate of not less than450 cm2 (1 ft2) is to be installed. The spike is toproject at least 150 mm (6 in.) above the uppermostpart of the craft, the conductor is to run clear of metalobjects and as straight as practicable, and the


grounding plate is to be located so that it is immersedunder all conditions of heel. Metallic rudders may beused as grounding plates.

b Primary conductors provided for lightningdischarge currents are to have a minimum cross-sectionof 50 mm2 in copper or equivalent surge-carryingcapacity in aluminum.

c Metallic pipes capable of generating electrostaticdischarges, due to the flow of liquids and gases are tobe bonded so as to be electrically continuousthroughout their length and are to be adequatelyearthed.

d Secondary conductors provided for theequalization of static discharges, bonding ofequipment, etc., but not for carrying lightningdischarges are to have a minimum cross-section of 5mm2 copper or equivalent surge current carryingcapacity in aluminum.

e The electrical resistance between bonded objectsand the basic structure is not to exceed 0.05 ohmexcept where it can be demonstrated that a higherresistance will not cause a hazard. The bonding path isto have sufficient cross-sectional area to carry themaximum current likely to be imposed on it withoutexcessive voltage drop.

f Each pressure refueling point is to be providedwith a means of bonding the fueling equipment to thecraft.

4/5B2.3 Generators

All generators are to be located with their shafts in afore-and-aft direction on the craft and are to operatesatisfactorily in accordance with the inclinationrequirements of 4/1.21. Where it is not practicable tomount the generators with the armature shafts in thefore-and-aft direction, their lubrication will requirespecial consideration. Provision is to be made toprevent oil or oil vapor from passing into the machinewindings.

4/5B2.5 Craft Service Motors

4/5B2.5.1 GeneralMotors for use in the machinery space above the floorplate or spaces where subject to mechanical injury, ordripping of oil or water are to have an enclosure of atleast IP22 protection in accordance with Table 4/5B.1.However where they are protected by drip covers, theymay have an enclosure of the lower protection gradethan IP22. The motors having a protection enclosure ofIP22 or lower are to be installed at a location highenough to avoid bilge water. Motors below the level ofthe floor plates are to have an enclosure of at least IP44protection. Where motors intended for service at seaare not mounted with the rotor shafts in the fore-and-aftdirection, the type of bearing and lubrication willrequire special consideration.

4/5B2.5.2 Pump MotorsMotors for operating plunger and close-coupled pumpsare to have the driving end entirely enclosed ordesigned to prevent leakage from entering the motor.

4/5B2.5.3 Motors on Weather DecksMotors for use on weather decks are to have anenclosure of at least IP56 protection or are to beenclosed in watertight housings.

4/5B2.5.4 Motors Below DecksMotors below decks are to be installed at a location asdry as practicable and away from steam, water, and oilpiping.

4/5B2.7 Accumulator Batteries

4/5B2.7.1 GeneralThe following requirements are applicable topermanently installed power, control and monitoringstorage batteries of acid or alkaline types. Batteries areto be so arranged that the trays are accessible andprovided with not less than 254 mm (10 in.) headroom.Where a relief valve is provided for dischargingexcessive gas due to overcharge, arrangements are tobe made for releasing the gas to the weather deck awayfrom any source of ignition.Accumulator batteries are not to be located in crewaccommodation.

4/5B2.7.2 Battery Installation and Arrangementsa Large Batteries Large storage batteries, those

connected to a charging device with an output of morethan 2 kW, are to be installed in a room assigned to thebattery only, but may be installed in a deck locker ifsuch a room is not available. No electrical equipment isto be installed in the battery rooms unless essential forthe operational purposes and certified safe for batteryroom atmosphere (See 4/5B7.1).

b Moderate-size Batteries Batteries of moderatesize, those connected to a charging device with a poweroutput of 0.2 kW up to and including 2 kW, may beinstalled in the battery room or may be installed inbattery lockers or deck boxes in the emergencygenerator room, machinery space or other suitablelocation. Cranking batteries are to be located as closelyas possible to the engine or engines served.

c Small Batteries Small batteries are to beinstalled in a battery box and may be located asdesired, except they are not to be located in sleepingquarters unless hermetically sealed.

d Battery Trays Trays for batteries are to bechocked with wood strips or equivalent to preventmovement and each tray is to be fitted withnonabsorbent insulating supports on the bottom andwith similar spacer blocks at the sides or withequivalent provision to secure air-circulation space allaround each tray.


e Identification of Battery Types Lead-acidbatteries and alkaline batteries, when placed in thesame battery compartment, are to be effectivelyidentified as to type and segregated.

4/5B2.7.3 Ventilationa Battery Rooms Battery rooms are to be

ventilated to avoid accumulation of flammable gas.Natural ventilation may be employed if ducts are rundirectly from the top of the battery room to the open airabove.If natural ventilation is impractical, mechanical exhaustventilation is to be provided with fan intake at the topof the room. Fans are to be of non-sparkingconstruction in accordance with 4/5B7.7 and capable ofcompletely changing the air in the battery room in notmore than two minutes. Alternatively, a lesserventilation rate may be considered, provided thatsatisfactory calculations are submitted substantiatingthat adequate ventilation is available to maintain theflammable gases within the battery room to a levelbelow the lower explosive limit (L.E.L.) at themaximum battery charging current. Where theventilation rate is based on low hydrogen emissiontype batteries, a warning notice to this effect is to beprovided in a visible place in the battery room.Openings for air inlet are to be provided near the floor.

b Battery Lockers Battery lockers are to beventilated, if practicable, similarly to battery rooms bya duct led from the top of the locker to the open air orto an exhaust ventilation duct. Louvers or equivalentare to be provided near the bottom for entrance of air.

c Deck Boxes Deck boxes are to be provided witha duct from the top of the box, terminating in a gooseneck, mushroom head or equivalent to prevent entranceof water. Holes for air inlet are to be provided on atleast two opposite sides of the box. The entire deckbox, including openings for ventilation, is to beweathertight to prevent entrance of spray or rain.

d Small Battery Boxes Boxes for small batteriesrequire no ventilation other than openings near the topto permit escape of gas.

4/5B2.7.4 Protection from CorrosionThe interiors of battery rooms, including the structuralparts and shelves therein, as well as ventilation inletsand outlets are to be painted with corrosion-resistantpaint. Shelves in battery rooms or lockers for acidbatteries are to have a watertight lining of sheet leadnot less than 1.6 mm (1/16 in.) on all sides. For alkalinebatteries the shelves are to be similarly lined with steelnot less than 0.8 mm (1/32 in.) thick. Alternatively, abattery room may be fitted with a watertight lead pan,steel for alkaline batteries, over the entire deck, carriedup not less than 152 mm (6 in.) on all sides. Deckboxes are to be lined in accordance with the abovealternative method. Boxes for small batteries are to belined to a depth of 76 mm (3 in.) consistent with themethods described above.

4/5B2.9 Switchboard

Switchboards are to be so arranged as to give easyaccess as may be needed to apparatus and equipment,without danger to personnel. Switchboards are to belocated in a dry place so as to provide a clear workingspace of at least 914 mm (36 in.) at the front of theswitchboard and a clearance of at least 610 mm (24 in.)at the rear which may be reduced to 457 mm (18 in.) inway of stiffeners or frames except that, forswitchboards which are enclosed at the rear and arefully serviceable from the front, clearance at the rearwill not be required unless necessary for cooling.Switchboards are to be secured to a solid foundation.They are to be self-supported, or be braced to thebulkhead or the deck above. In case the last method isused, means of bracing is to be flexible to allowdeflection of the deck without buckling the assemblystructure.

4/5B2.11 Distribution boards

4/5B2.11.1 Location and ProtectionDistribution boards are to be located in accessiblepositions and not in such spaces as bunkers,storerooms, cargo holds or compartments allottedalternately to passengers or cargo. Distribution boardsare to have approved non-combustible non-hygroscopicenclosures. Metal enclosures and all exposed metalparts in non-metallic enclosures are to be earthed to thecraft's structure. All cases are to be of adequatemechanical strength.

4/5B2.11.2 Switchboard-type Distribution boardsDistribution boards of the switchboard type, unlessinstalled in machinery spaces or in compartmentsassigned exclusively to electric equipment andaccessible only to authorized personnel, are to becompletely enclosed or protected against accidentalcontact and unauthorized operation.

4/5B2.11.3 Safety-type PanelsIf the method of operation demands the handling ofswitches by persons unfamiliar with electricalequipment, the distribution board is to be of the safetytype; this type of distribution board is to be used forcontrolling branch lighting circuits. Dead front typepanels are to be used where voltage to earth is in excessof 55 volts D.C. or 55 volts A.C. r.m.s. betweenconductors.

4/5B2.13 Motor Controllers and Control Centers

4/5B2.13.1 Location and InstallationMotor control centers are to be located in a dry place.Clear working space is to be provided around motorcontrol centers to enable doors to be fully opened andequipment removed for maintenance and replacement.Motor control centers are to be secured to a solidfoundation, be self-supported, or be braced to thebulkhead.


4/5B2.13.2 Disconnecting Arrangementsa Device Means are to be provided for

disconnecting the motor and controller from all supplyconductors, except that a manually operated switch orcircuit breaker may serve as both controller anddisconnecting means (see 4/5C4.17.2).

b Location The disconnecting device may be inthe same enclosure with the controller, or may be in aseparate enclosure, and is to be externally operated.The branch-circuit switch or circuit breaker on thepower-distribution board or switchboard may serve asthe disconnect device if in the same compartment withthe controller.

c Locking Means If the disconnecting device isnot within sight of both motor and controller, or if it ismore than 15.25 m (50 ft) from either, it is to bearranged for locking in the open position. Where aremote control is required for a motor, this lockingdevice is not to be provided for the local start or stopswitch at the machine side and is to be provided at thefeeder circuit breaker for such motor.

d Identification Plate The disconnect switch, ifnot adjacent to the controller, is to be provided with anidentification plate.

e Open and Close Indications The disconnectdevice is to indicate by a position of the handle, orotherwise, whether it is open or closed.

4/5B2.13.3 Indicating-light CircuitsWhere indicating-light circuits are employed, theirpotential is to be limited to 150 volts if the opening ofthe foregoing disconnecting devices does not de-energize the indicating circuit.

4/5B2.15 Resistors for Control Apparatus

The resistor is to be protected against corrosion eitherby rust-proofing or embedding in a protective material.Resistors are to be located in well-ventilatedcompartments and are to be mounted with ampleclearances, about 305 mm (12 in.) to prevent excessiveheating of adjacent craft's structure or dangerousoverheating of unprotected combustible material. Thearrangement of the electrical equipment and wiringlocated within these spaces is to be such as to preventtheir exposure to ambient temperatures in excess of thatfor which they have been designed.

4/5B2.17 Lighting Fixtures

Lighting fixtures are be so arranged as to preventtemperature rises which could damage the cables andwiring, and to prevent surrounding material frombecoming excessively hot.

4/5B2.19 Heating Equipment

Electric radiators, if used, are to be fixed in positionand be so constructed as to reduce fire risks to aminimum. Electric radiators of the exposed-elementtype are not to be used.

4/5B2.21 Magnetic Compasses

Precautions are to be taken in connection withapparatus and wiring in the vicinity of the magneticcompass to prevent disturbance of the needle fromexternal magnetic fields.

4/5B2.23 Portable Equipment and OutletsPortable equipment are not to be used in hazardousareas nor are portable lights to be used for berth lightsin passenger accommodations or crew’s quarters.

4/5B2.25 Receptacles and Plugs of DifferentRatings

Receptacles and plugs of different electrical ratings arenot to be interchangeable. In cases where it is necessaryto use 230 volts portable equipment, the receptacles fortheir attachment are to be of a type which will notpermit attaching 115 volts equipment.

4/5B3 Cable Installation

4/5B3.1 General Considerations

4/5B3.1.1 Continuity of CablingElectric cables are to be installed in continuous lengthsbetween terminations at equipment or in cable junctionboxes. See 4/5B3.33. However, approved splices willbe permitted at interfaces of new construction modules,when necessary to extend existing circuits for a craftundergoing repair or alteration, and in certain cases toprovide for cables of exceptional length (See4/5B3.29).

4/5B3.1.2 Choice of CablesThe rated operating temperature of the insulatingmaterial is to be at least 10 oC (18 oF) higher than themaximum ambient temperature likely to exist, or to beproduced, in the space where the cable is installed.

4/5B3.1.3 Cable Voltage Drop for New InstallationThe cross-sectional area of conductors are to be sodetermined that the drop in voltage from the main oremergency switchboard bus-bars to any and every pointof the installation when the conductors are carrying themaximum current under normal steady conditions ofservice, will not exceed 6% of the nominal voltage. Forsupplies from batteries with a voltage not exceeding 55V this figure may be increased to 10%.


The above values are applicable under normal steadyconditions. Under special conditions of short duration,such as motor starting, higher voltage drops may beaccepted provided the installation is capable ofwithstanding the effects of these higher voltage drops.

4/5B3.1.4 Restricted Location of CablingCables and wiring are to be installed and supported insuch a manner as to avoid chafing or other damage.Cables are to be located with a view to avoiding, as faras practicable, spaces where excessive heat and gasesmay be encountered, also spaces where they may beexposed to damage, such as exposed sides ofdeckhouses. Cables are not to be installed in the bilgearea unless protected from bilge water.

4/5B3.1.5 Means of Drainage from CableEnclosuresWhere cables are installed in a cable draw box andhorizontal pipes or the equivalent used for cableprotection, means of drainage are to be provided.

4/5B3.1.6 High Voltage CablesCables serving systems above 1 kV are not to bebunched with cables serving systems of 1 kV andbelow.

4/5B3.3 Insulation Resistance for New Installation

Each power and each light circuit is to have aninsulation resistance between conductors and betweeneach conductor and earth of not less than the followingvalues.

Up to 5 amperes load 2 meg ohms10 amperes load 1 meg ohm25 amperes load 400,000 ohms50 amperes load 250,000 ohms100 amperes load 100,000 ohms200 amperes load 50,000 ohmsOver 200 amperes load 25,000 ohms

If the above values are not obtained, any or allappliances connected to the circuit may bedisconnected for this test.

4/5B3.5 Protection for Electric-magnetic Induction

4/5B3.5.1 Multiple Conductor CablesAll phase conductors of alternating-current cables areto be contained within the same sheath in order toavoid overheating due to induction by use of multipleconductor cables.

4/5B3.5.2 Single Conductor CablesSingle conductor cables may be used for powertransmission provided the following arrangements arecomplied with;

a Cables are supported on non-fragile insulators;b There are to be no magnetic materials between

cables of a group; andc Where single conductor cables are run in

bunches, each group of cables is to comprise 360electrical degrees, and where run for considerablelength, individual cables are to be transposedthroughout the length in order to cancel out anypossible effects of magnetic interference.

Additionally, single conductor cables may be usedwhen carrying negligible current (for control circuits,etc.). See 4/5C7.1.5 for armor.

4/5B3.5.3 Non-shielded Signal CablesExcept for fiber optic cables, non-shielded signalcables for automation and control systems essential forthe safe operation of the craft which may be affectedby electromagnetic interference are not to be run in thesame bunch with power or lighting cables.

4/5B3.7 Joints and Sealing

Cables not having a moisture-resistant insulation are tobe sealed against the admission of moisture by methodssuch as taping in combination with insulatingcompound or sealing devices. Cables are to be installedin such a manner that stresses on the cable are nottransmitted to the conductors. Terminations and jointsin all conductors are to be so made as to retain theoriginal electrical, flame retarding and, wherenecessary, fire resisting properties of the cable.Terminal boxes are to be secured in place and themoisture-resistant jacket is to extend through the cableclamp. Enclosures for outlets, switches, and similarfittings are to be flame and moisture-resistant and ofadequate mechanical strength and rigidity to protect thecontents and to prevent distortion under all likelyconditions of service. See also 4/5B3.17.1 and4/5B3.29.

4/5B3.9 Support and Bending

4/5B3.9.1 SupportWhere cables are run in groups, they are to besupported in metal hangers arranged as far aspracticable to permit painting of the surroundingstructure without undue disturbance to the installation.Single-cable runs may be supported by metal clipsscrewed directly to deck or bulkhead except onwatertight bulkheads. Power supply cables grouped in asingle hanger are to be limited preferably to two banks.Supports for cables are to be spaced less than 610 mm(24 in.) apart in both the horizontal and vertical


directions. Cables supported by clips or straps on theunder side of beams are to be run on backing plates,cable racks or the equivalent. Metal supports are to bedesigned to secure cables without damage to insulationor armor and are to be so arranged that the cable willbear over a length of at least 12.7 mm (0.5 in.). Plasticcable straps are not to be used for cable support butmay be used with a combination of metallic cablestraps for retaining cables.

4/5B3.9.2 Bending RadiusFor bending radius requirements, see Table 4/5B.2.

4/5B3.11 Cable Run in Bunches

4/5B3.11.1 Reduction of Current RatingWhere cables which may be expected to operatesimultaneously are laid close together in a cable bunchin such a way that there is an absence of free aircirculation around them the following reduction factoris to be applied to the current rating obtained fromTable 4/5C.10:

Number of cables in one bunch Reduction factorone to six 1.0seven to twelve 0.85

Bunches of more than twelve cables will be subject tospecial consideration based on the type and service ofthe various cables in the bunch.

4/5B3.11.2 Clearance and SegregationA clearance is to be maintained between any two cablebunches of at least the diameter of the largest cable ineither bunch. Otherwise, for the purpose of determiningthe number of cables in the bunch the total number ofcables on both sides of the clearance will be used.

4/5B3.11.3 Cable of Lower ConductorTemperatureThe current rating of each cable in a bunch is to bedetermined based on the lowest conductor temperaturerating of any cable in the bunch.

4/5B3.13 Deck and Bulkhead Penetrations

Where cables pass through watertight, firetight, orsmoke-tight bulkheads or decks, the penetrations are tobe made through the use of approved stuffing tubes,transit devices, or pourable materials which willmaintain the watertight, firetight, or smoke-tightintegrity of the bulkheads or decks. Additionally, eachsuch stuffing tube, transit device, or pourable materialis to be of a character so as not to damage the cablephysically or through chemical action or through heatbuild-up. When cables pass through non-watertightbulkheads where the bearing surface is less than 6.4

mm (0.25 in.), the holes are to be fitted with bushingshaving rounded edges and a bearing surface for thecable of at least 6.4 mm (0.25 in.) in length. Wherecables pass through deck beams, or similar structuralparts, all burrs are to be removed in way of the holesand care is to be taken to eliminate sharp edges. Wherecable conduit pipe or equivalent is carried throughdecks or bulkheads, arrangements are to be made tomaintain the integrity of the water or gas tightness ofthe structure. Cables are not to pass through a collisionbulkhead.

4/5B3.15 Mechanical Protection

4/5B3.15.1 Metallic ArmorElectric cables installed in locations liable to damageduring normal operation of the craft are to be providedwith braided metallic armor and otherwise suitablyprotected from mechanical injury as appropriate for thelocation. See also 4/5B7.1.3 for cables in hazardousareas.4/5B3.15.2 Conduit Pipe or Structural ShapesWhere cables are installed in locations in way ofhatches, tank tops, open decks subject to seas, andwhere passing through decks, are to be protected bysubstantial metal shields, structural shapes, pipe orother equivalent means. All such coverings are to be ofsufficient strength to provide effective protection to thecables. When expansion bends are fitted they are to beaccessible for maintenance. Where cables are installedin metal piping or in a metal conduit system, suchpiping and systems are to be earthed and are to bemechanically and electrically continuous across alljoints.

4/5B3.17 Emergency and Essential Feeders

4/5B3.17.1 LocationCables and wiring serving essential services oremergency power, lighting, internal communications orsignals are to be so far as practicable be routed clear ofgalleys, laundries, machinery spaces and their casingand other high fire risk areas. Cables connecting firepumps to the emergency switchboard are to be of a fireresistant type where they pass through high fire riskareas. Cables are to be run in such a manner as topreclude damage by heating of the bulkheads that maybe caused by a fire in an adjacent space.

4/5B3.17.2 Requirements by the GovernmentalAuthorityAttention is directed to the requirements of thegovernmental authority of the country, whose flag thecraft flies, for the installation of emergency circuitsrequired in various types of craft.


4/5B3.19 Mineral Insulated Cables

At all points where mineral-insulated metal-sheathedcable terminates, an approval seal is to be providedimmediately after stripping to prevent entrance ofmoisture into the mineral insulation. In addition, theconductors extending beyond the sheath are to beinsulated with an approved insulating material. Whenmineral-insulated cable is connected to boxes orequipment, the fittings are to be approved for theconditions of service. The connections are to be inaccordance with the manufacturers installationrecommendation.

4/5B3.21 Fiber Optic Cables

The installation of fiber optic cables is to be inaccordance with the manufacturer's recommendationsto prevent sharp bends where the fiber optic cablesenter the equipment enclosure. Consideration is to begiven to the use of angled stuffing tubes. The cables areto be installed so as to avoid abrading, crushing,twisting, kinking or pulling around sharp edges.

4/5B3.23 Battery Room

Where cables enter battery rooms, the holes are to bebushed as required for watertight bulkheads in4/5B3.13. All connections within battery rooms are tobe resistant to the electrolyte. Cables are to be sealed toresist the entrance of electrolyte by spray or creepage.The size of the connecting cable is to be based oncurrent-carrying capacities given in Table 4/5C.10 andthe starting rate of charge or maximum discharge rate,whichever is the greater, is to be taken intoconsideration in determining the cable size.

4/5B3.25 Paneling and Dome Fixtures

Cables may be installed behind paneling, provided allconnections are accessible and the location ofconcealed connection boxes is indicated. Where a cablestrip molding is used for cable installation on theincombustible paneling, it is to be of incombustiblematerial. Dome fixtures are to be installed so that theyare vented or they are to be fitted with fire-resistantmaterial in such a manner as to protect the insulatedwiring leading to the lamps and any exposed woodworkfrom excessive temperature.

4/5B3.27 Sheathing and Structural Insulation

Cables may be installed behind sheathing, but they arenot to be installed behind nor imbedded in structuralinsulation; they are to pass through such insulation atright angles and are to be protected by a continuouspipe with a stuffing tube at one end. For deckpenetrations this stuffing tube is to be at the upper end

of the pipe and for bulkhead penetrations it is to be onthe uninsulated side of the bulkhead. For refrigerated-space insulation the pipe is to be of phenolic or similarheat-insulating material joined to the bulkhead stuffingtube or a section of such material is to be insertedbetween the bulkhead stuffing tube and the metallicpipe.

4/5B3.29 Splicing of Electrical Cables

4/5B3.29.1 Basis of ApprovalReplacement insulation is to be fire resistant and is tobe equivalent in electrical and thermal properties to theoriginal insulation. The replacement jacket is to be atleast equivalent to the original impervious sheath and isto assure a watertight splice. Splices are to be madeusing an approved splice kit which contains thefollowing:

- Connector of correct size and number- Replacement insulation- Replacement jacket- Instructions for use

In addition, prior to approval of a splicing kit, it will berequired that completed splices be tested for fireresistance, watertightness, dielectric strength, etc. to thesatisfaction of the Surveyor. This requirement may bemodified for splice kits which have had such testsconducted and reported on by an independent agencyacceptable to the Bureau.4/5B3.29.2 InstallationAll splices are to be made after the cable is in place andare to be accessible for inspection. The conductorsplice is to be made using a pressure type buttconnector by use of a one-cycle compression tool. See4/5B7.1.3 for splices in hazardous area.

4/5B3.29.3 ProtectionSplices may be located in protected enclosures or inopen wireways. Armored cables having splices will notbe required to have the armor replaced provided thatthe remaining armor has been earthed in compliancewith 4/5B4.9 or provided the armor is made electricallycontinuous. Splices are to be so located such thatstresses (as from the weight of the cable) are notcarried by the splice.

4/5B3.31 Splicing of Fiber Optic Cables

Splicing of fiber optic cables is to be made by means ofapproved mechanical or fusion methods.

4/5B3.33 Cable Junction Box

Except for propulsion cables, junction boxes may beused in the installation of electric cables aboard thecraft provided the plans required by 4/5B1.3 for


junction boxes are submitted and the followingrequirements are complied with.

1 The design and construction of the junctionboxes are to comply with 4/5C6.7 as well assubparagraph 2. below.

2 The junction boxes are to be suitable for theenvironment in which they are installed, i.e., explosion-proof in hazardous areas, watertight or weathertight ondeck, etc.

3 Separate junction boxes are to be used forfeeders and circuits of different rated voltage levels.Each junction box is to be appropriately identified asregards the rated voltage of the feeders and circuits itcontains.

4 The junction boxes for emergency feeders andcircuits are to be separate from those used for normalcraft service feeders and circuits.

5 The junction boxes for control and alarm circuitsare to be separate from those for power circuits. Also,where separate means of control is required (e.g.steering gear), the junction boxes for such circuits areto be separated.

6 Cables are to be supported, as necessary, withinjunction boxes so as not to put stress (as from theweight of the cable) on the cable contact mountings,The connections are to be provided with locking typeconnections.In addition to the above, the applicable requirements in4/5B3 and 4/5C7 regarding cable installation andapplication details are to be complied with.

4/5B4 Earthing

4/5B4.1 General

Exposed metal parts of electrical machines orequipment which are not intended to be live but whichare liable under fault conditions to become live are tobe earthed unless the machines or equipment are:

1 supplied at a voltage not exceeding 55 V D.C. or55 V A.C. r.m.s. between conductors; auto-transformers are not to be used for the purpose ofachieving this voltage; or

2 supplied at a voltage not exceeding 250 V A.C.r.m.s. by safety isolating transformers supplying onlyone consuming device; or

3 constructed in accordance with the principle ofdouble insulation,

4/5B4.3 Permanent Equipment

The metal frames or cases of all permanently installedgenerators, motors, controllers, instruments and similarequipment are to be permanently earthed through ametallic contact with the craft's structure.

Alternatively, they are to be connected to the hull by aseparate conductor in accordance with 4/5B4.5. Whereoutlets, switches and similar fittings are of non-metallicconstruction, all exposed metal parts is to be earthed.

4/5B4.5 Connections

4/5B4.5.1 GeneralAll earthing conductors are to be of copper or othercorrosion resistant material and is to be protectedagainst damage. The nominal cross-sectional area ofevery copper earthing conductor is to be not less thanthat required by Table 4/5B.3.

4/5B4.5.2 Earthed Distribution SystemEarthing conductors in earthed distribution system areto comply with 4/5B4.5.1, except that the earthingconductor in line C4 of Table 4/5B.3 is to be A/2.

4/5B4.5.3 Connection to Hull Structure.All connection of an earth-continuity conductor orearthing lead to the craft's structure is to be made in anaccessible position and is secured by a screw of brassor other corrosion-resistant material having crosssectional area equivalent to the earth-continuityconductor or earthing lead but not less than 4 mm (0.16in.) in diameter. The earth connection screw is to beused for this purpose only. See 4/6.7.12 for control ofstatic electricity.

4/5B4.7 Portable Cords

Receptacle outlets operating at 55 volts D.C. or 55volts A.C. r.m.s. or more are to have a earthing pole.

4/5B4.9 Cable Metallic Covering

All metal sheaths, armor of cable and mineral-insulatedmetal-sheathed cable are to be electrically continuousand are to be earthed to the metal hull at each end ofthe run except that final subcircuits may be earthed atthe supply end only. All metallic coverings of powerand lighting cables passing through hazardous area orconnected to equipment in such an area are to beearthed at least at each end. See also 4/11.3.7.e3.

4/5B4.11 Lightning Earth Conductors

Each wooden mast or topmast is to be fitted withlightning earth conductors. They need not be fitted tosteel masts.


4/5B7 Equipment and Installation in HazardousArea

4/5B7.1 General Consideration

4/5B7.1.1 GeneralElectrical equipment and wiring are not to be installedin hazardous area unless essential for operationalpurposes.

4/5B7.1.2 Lighting CircuitsAll switches and protective devices for lighting fixturesin hazardous area are to interrupt all poles or phasesand are to be located in a non-hazardous area. Theswitches and protective devices for lighting fixtures areto be suitably labeled for identification purposes.

4/5B7.1.3 Cables InstallationCables in hazardous areas are to be armored ormineral-insulated metal-sheathed. Where these cablespass through boundaries of such locations, they are tobe run through gastight fittings. No splices are allowedin hazardous areas except in intrinsically-safe circuits.

4/5B7.1.4 Permanent Warning PlatesPermanent warning plates are to be installed in thevicinity of hazardous areas in which electricalequipment is installed, such as pump room, to advisepersonnel carrying out maintenance, repair or surveysof availability of the booklet/list of equipment inhazardous areas referenced in 4/5B1.5, if required fortheir use.

4/5B7.3 Certified-safe and Pressurized TypeEquipment and Systems

4/5B7.3.1 Installation ApprovalElectrical equipment in hazardous areas is to be of atype suitable for such locations. Where permitted bythe Guide, electrical equipment of certified safe type,such as explosion-proof type and intrinsically-safeelectrical instruments, circuitry and devices, will beapproved for installation provided such equipment hasbeen type-tested and certified by a competentindependent testing laboratory as explosion-proof orintrinsically-safe and provided that there is nodeparture in the production equipment from the designso tested and approved.

4/5B7.3.2 Intrinsically-safe Systema Separation Intrinsically-safe systems are to be

completely separated and independent of all otherelectric systems. Intrinsically-safe cables are to haveshielded conductors or to be installed a minimum of 50mm (2 in.) from other electric cables and are not tooccupy an enclosure (such as a junction box or terminalcabinet) with non-intrinsically-safe circuits.

b Physical Barrier When intrinsically-safecomponents are located by necessity within enclosuresthat contain non-intrinsically-safe systems, such ascontrol consoles and motor starters, such componentsare to be effectively isolated in a sub-compartment byphysical barriers having a cover or panel secured bybolts, locks, allen-screws, or other approved methods.The physical barrier is not intended to apply to thesource of power for the intrinsically-safe circuitinterface.

c Nameplate The sub-compartment is to have anidentifying nameplate indicating that the equipmentwithin is intrinsically-safe and that unauthorizedmodification or repairs are prohibited.

d Replacement Unless specifically approved,replacement equipment for intrinsically-safe circuits isto be identical to the original equipment.

4/5B7.3.3 Pressurized EquipmentPressurized equipment is to consist of separately-ventilated enclosures supplied with positive-pressureventilation from a closed-loop system or from a sourceoutside the hazardous areas, and provision is to bemade such that the equipment cannot be energized untilthe enclosure has been purged with a minimum of tenair changes and required pressure is obtained.Ventilating pipes are to have a minimum wall thicknessof 3 mm (0.12 in. or 11 gage). In the case of loss ofpressurization, power is to be automatically removedfrom the equipment, unless this would result in acondition more hazardous than the created by failure tode-energized the equipment. In this case, in lieu ofremoval of power, an audible and visual alarm is to beprovided at a normally manned control station.Pressurized equipment in compliance with IECPublication 79-2, NFPA 496 or other recognizedstandard will also be acceptable.

4/5B7.5 Paint Stores

4/5B7.5.1 GeneralElectrical equipment in paint stores and in ventilationducts serving such spaces where permitted by4/5B7.1.1 is to comply with the requirements for groupIIB class T3 in IEC Publication 79.The following type of equipment will be acceptable forsuch spaces.

a intrinsically-safe defined by 4/5.3.6b explosion-proof defined by 4/5.3.3c pressurized defined by 4/5.3.12d increased safety defined by 4/5.3.7e other equipment with special protection

recognized as safe for use in explosive gas atmospheresby a national or other appropriate authority


4/5B7.5.2 Open Area Near Ventilation OpeningsIn the areas on open deck within 1 m (3.3 ft) ofventilation inlet or within 1 m (3.3 ft) (if natural) or 3m (10 ft) (if mechanical) of exhaust outlet, electricalequipment and cables where permitted by 4/5B7.1.1are to be in accordance with 4/5B7.1.2, 4/5B7.1.3 and4/5B7.3.1.

4/5B7.5.3 Enclosed Access SpacesThe enclosed spaces giving access to the paint storemay be considered as non-hazardous, provided that:

a the door to the paint store is gastight with self-closing devices without holding back arrangements,

b the paint store is provided with an acceptable,independent, natural ventilation system ventilated froma safe area, and

c warning notices are fitted adjacent to the paintstore entrance stating that the store contains flammableliquids.

4/5B7.7 Non-sparking Fans

4/5B7.7.1 Design Criteriaa Air Gap The air gap between the impeller and

the casing is to be not less than 10% of the shaftdiameter in way of the impeller bearing but not lessthan 2 mm (0.08 in.). It need not be more than 13 mm(0.5 in.).

b Protection Screen Protection screens of notmore than 13 mm (0.5 in.) square mesh are to be fittedin the inlet and outlet of ventilation ducts to prevent theentrance of object into the fan casing.

4/5B7.7.2 Materialsa Impeller and its Housing Except as indicated in

4/5B7.7.2c below, the impeller and the housing in wayof the impeller are to be made of alloys which arerecognized as being spark proof by appropriate test.

b Electrostatic Charges Electrostatic charges bothin the rotating body and the casing are to be preventedby the use of antistatic materials. Furthermore, theinstallation on board of the ventilation units is to besuch as to ensure the safe bonding to the hull of theunits themselves.

c Acceptable Combination of Materials Testsreferred to in 4/5B7.7.2a above are not required forfans having the following combinations:

1 Impellers and/or housings of nonmetallicmaterial, due regard being paid to theelimination of static electricity;

2 Impellers and housings of non-ferrousmaterials;

3 impellers of aluminum alloys or magnesiumalloys and a ferrous (including austeniticstainless steel) housing on which a ring ofsuitable thickness of non-ferrous materials isfitted in way of the impeller;

4 Any combination of ferrous (includingaustenitic stainless steel) impellers andhousings with not less than 13 mm (0.5 in.)tip design clearance.

d Unacceptable Combination of Materials Thefollowing impellers and housings are considered assparking-producing and are not permitted:

1 Impellers of an aluminum alloy or magnesiumalloy and a ferrous housing, regardless of tipclearance;

2 Housing made of an aluminum alloy or amagnesium alloy and a ferrous impeller,regardless of tip clearance;

3 Any combination of ferrous impeller andhousing with less than 13 mm (0.5 in.) designtip clearance.

4/5B7.7.3 Type TestType tests on the finished product are to be carried outusing an acceptable national or international standard.The tests need not to be witnessed by the Surveyor forindividual fans produced on a production line basis,provided the Surveyor is satisfied from periodicinspections and the manufacturer's quality assuranceprocedures that the fans are being satisfactorily testedto appropriate standards. See also 4/1.3.


Table 4/5B.1 Minimum Degree of Protection[See 4/5B2.1.1]

(1) (2) (3) EQUIPMENT - : Not recommended to be installedSwitchboards, Distribution boards, Motor Control Center,and Controller (See 4/5B2.9 to 4/5B2.13)

Generators (See 4/5B2.3)Example Condition Motors (See 4/5B2.5)

of of Transformers, ConvertersLocation Location Lighting fixtures (See 4/5B2.17)

Heating appliances(See 4/5B2.19)

Accessories (*2)REMARKS

Dry Accommodation space Danger of touching live parts IP20 - IP20 IP20 IP20 IP20 IP20

Dry Control Rooms only IP20 - IP20 IP20 IP20 IP20 IP20

Control rooms (Operating

compartment)

Danger of dripping liquid

and/or moderate mechanical

damage

IP22 - IP22 IP22 IP22 IP22 IP22

Machinery spaces above

floor plates

IP22 IP22 IP22 IP22 IP22 IP22 IP44

Steering gear rooms IP22 IP22 IP22 IP22 IP22 IP22 IP44

Refrigerating machinery

rooms

IP22 - IP22 IP22 IP22 IP22 IP44

Emergency machinery rooms IP22 IP22 IP22 IP22 IP22 IP22 IP44

General store rooms IP22 - IP22 IP22 IP22 IP22 IP22

Pantries IP22 - IP22 IP22 IP22 IP22 IP44

Provision rooms IP22 - IP22 IP22 IP22 IP22 IP22

Bathrooms & Showers Increased danger of - - - - IP34 IP44 IP55

Machinery spaces below

floor plates

liquid and/or mechanical

damage

- - IP44 - IP34 IP44 IP55

(*1)

Closed fuel oil or lubricating

oil separator rooms

IP44 - IP44 - IP34 IP44 IP55

(*1)

Ballast pump rooms Increased danger of IP44 - IP44 IP44 IP34 IP44 IP55

Refrigerated rooms liquid and mechanical - - IP44 - IP34 IP44 IP55

Galleys and Laundries damage IP44 - IP44 IP44 IP34 IP44 IP44

Open decks Exposure to heavy seas IP56 - IP56 - IP55 IP56 IP56

Bilge wells Exposure to submersion - - - - IPX8 - IPX8

Notes:(*1) Socket outlets are not to be installed in machinery spaces below the floor plates, enclosed fuel and lubricating oilseparator rooms or spaces requiring certified safe type equipment(*2) "Accessory" includes switches, detectors, junction boxes, etc. Accessories, which are acceptable for use in hazardousareas, are limited by the condition of the areas. Specific requirements are given in the Guide. See 4/5B2.23.


Table 4/5B.2 Minimum Bending Radii of Cables[See 4/5B3.9.2]

Cable Construction Overall diameterof cable (D)

Minimum internalbending radius (timesoverall diameter D)

Insulation Outer Covering

Thermoplastic andMetal-sheathed armored

or braidedAny 6

elastomeric Other 25 mm (1 in.) and less 4finish Exceeding 25 mm (1 in.) 6

Mineral Hard metal-sheathed Any 6

TABLE 4/5B.3 Size of Earth-continuity Conductors andEarthing Connections[See 4/5B4.5]

Type of earthing connectionCross-sectional areaof associated currentcarrying conductor

(A)

Minimum cross-sectional area ofcopper earthing connection

Earth-continuity conductor A1 A ≤ 16 mm2 A

in flexible cable or A2 16 mm2 < A ≤ 32 mm2 16 mm2

flexible cord A3 A > 32 mm2 A/2

For cables having an insulated earth-continuity conductor

B1a A ≤ 1.5 mm2 1.5 mm2

B1b 1.5 mm2 < A ≤ 16 mm2 A

Earth-continuity conductor B1c 16 mm2 < A ≤ 32 mm2 16 mm2

incorporated in fixed cable B1d A > 32 mm2 A/2

For cables with bare earth wire in direct contact with the lead sheath

B2a A ≤ 2.5 mm2 1 mm2

B2b 2.5 mm2 < A ≤ 6 mm2 1.5 mm2

C1aA ≤ 2.5 mm2

Stranded earthing connection :1.5 mm2 for A ≤ 1.5 mm2

A for A > 1.5 mm2

Separate fixed earthing C1b Unstranded earthing connection: 2.5 mm2

conductor C2 2.5 mm2 < A ≤ 8 mm2 4 mm2

C3 8 mm2 < A ≤ 120 mm2 A/2

C4 A > 120 mm2 70 mm2 (See note 1)

[NOTE](1) For earthed distribution systems, the size of earthing conductor need not exceed A/2. (2) Conversion Table for mm2 to circular mils:

mm2 circ. mils mm2 circ. mils mm2 circ. mils mm2 circ. mils

1 1,973 2.5 4,933 6 11,841 70 138,147

1.5 2,960 4 7,894 16 31,576 120 236,823

PART 4 SECTION 5|33 Electrical Installations -- Part C. Machinery and Equipment

Part C. Machinery andEquipment

4/5C1 Plans and Data to Be Submitted

4/5C1.1 Generators and Motors of 100 kW andOver

Drawings showing assembly, seating arrangements,terminal arrangements, shafts, coupling, coupling bolts,stator and rotor details are to be submitted for reviewtogether with data for complete rating, class ofinsulation, designed ambient temperature, temperaturerise, weights and speeds for rotating parts. Plans to besubmitted for generator prime movers are given in4/3.17 and 4/4.3 of the “Rules for Building andClassing Steel Vessels”.

4/5C1.3 Generators and Motors Below 100 kW

Complete rating, class of insulation, and degree ofenclosure.

4/5C1.5 Switchboards, Distribution Boards, etc. forEssential or Emergency Services

For switchboards, distribution boards, battery chargers,motor control centers, controllers for essential servicesor emergency services, drawings showing arrangementsand details, front view, and installation arrangementsare to be submitted for review together with data forprotective device rating and setting, type of internalwiring, and size and rated current carrying capacity(together with short-circuit current data) of bus barsand internal wiring for power circuit. In addition, aschematic or logic diagram with a written description,giving the sequence of events and system operatingprocedures for electrical power supply management onswitchboards, and sequential or automatic changeoverof the motors are also to be submitted for review.

4/5C2 Rotating Machines

4/5C2.1 General

4/5C2.1.1 ApplicationsAll rotating electrical machines of 100 kW and over areto be constructed and tested in accordance with thefollowing requirements to the satisfaction of theSurveyor. All rotating electrical machines below 100kW are to be constructed and equipped in accordancewith good commercial practice, and will be acceptedsubject to a satisfactory performance test conducted tothe satisfaction of the Surveyor after installation.

4/5C2.1.2 Certification on Basis of an ApprovedQuality Assurance Program

See 4/1.3.

4/5C2.1.3 Referencesa Inclination For the requirements covering

inclination for design condition, see 4/1.21.b Insulation Material For the requirements

covering insulation material, see 4/5.13.c Capacity of Generators For requirements

covering main generator capacity, see 4/5A2.1.2 and4/5A2.5. For requirements covering emergencygenerator capacity, see 4/5A3.3.1.

d Power Supply by Generators For requirementscovering power supply by main or emergencygenerator, see 4/5A2.1.2 and 4/5A3.5.2 respectively.

e Protection for Generator Circuits Forrequirements covering protection for generator, see4/5A5.3, 4/5A5.5 and 4/5A5.7.

f Protection for Motor Circuits For requirementscovering protection for motor branch circuit, see4/5A5.13.

g Installation For requirements coveringinstallation, see 4/5B2.3 for generators and 4/5B2.5 formotors.

h Protection Enclosures and its Selection Forrequirements covering degree of the protection and theselection of equipment, see 4/5.15 and 4/5B2.1respectively.

4/5C2.3 Testing and Inspection

4/5C2.3.1 Applicationsa Machines of 100 kW and Over All rotating

machines of 100 kW and over are to be tested inaccordance with Table 4/5C.1 in the presence of andinspected by the Surveyor, preferably at the plant of themanufacturer.

b Machines Below 100 kW For machines of lessthan 100 kW, the tests may be carried out by themanufacturer whose certificate of tests will beacceptable and is to be submitted upon request from theBureau.

4/5C2.3.2 Special Testing ArrangementsIn cases where all of the required tests are not carriedout at the plant of the manufacturer, the Surveyor is tobe notified and arrangements are to be made so that theremaining tests will be witnessed.

4/5C2.5 Insulation Resistance Measurement

The resistance is to be measured before thecommencement of the testing and after completion ofthe testing for all circuits. Circuits or groups of circuitsof different voltages above earth are to be testedseparately. This test is to be made with at least 500


volts D.C. and the insulation resistance in megohms ofthe circuits while at their operating temperatures is tobe normally at least equal to:

Rated Voltage of the Machine(Rating in kVA/100) + 1000

The minimum insulation resistance of the fields ofmachines separately excited with voltage less than therated voltage of the machine is to be of the order ofone-half to one megohm.4/5C2.6 Overload and Overcurrent Capability

4/5C2.6.1 A.C. GeneratorsA.C. generators are to be capable of withstanding acurrent equal to 1.5 times the rated current for not lessthan 30 seconds.

4/5C2.6.2 A.C. Motorsa Overcurrent Capacity Three phase motors,

except for commutator motors, having rated outputs notexceeding 315 kW and rated voltages not exceeding 1kV are to be capable of withstanding a current equal to1.5 times the rated current for not less than 2 minutes.For three-phase and single phase motors having ratedoutputs above 315 kW the overcurrent capacity is to bein accordance with the manufacturer’s specification.

b Overload Capacity Three-phase inductionmotors are to be capable of withstanding for 15seconds, without stalling or abrupt change in speed, anexcess torque of 60 % of their rated torque, the voltageand frequency being maintained at their rated values.

c Overload Capacity for Synchronous MotorsThree phase synchronous motors are to be capable ofwithstanding an excess torque as specified below for 15seconds without falling out of synchronism, theexcitation being maintained at the value correspondingto the rated load.

Synchronous (wound rotor)induction motors:

35% excess torque

Synchronous (cylindricalrotor) motors:

35% excess torque

Synchronous (salient pole)motors:

50% excess torque

When automatic excitation is used, the limit of torquevalues are to be the same as with the excitationequipment operating under normal conditions.4/5C2.7 Dielectric Strength of Insulation

4/5C2.7.1 ApplicationThe dielectric test voltage is to be successively appliedbetween each electric circuit and all other electriccircuits and metal parts earthed and for direct-current(D.C.) rotating machines between brush rings ofopposite polarity. Interconnected polyphase windingsare to be considered as one circuit. All windings exceptthat under test are to be connected to earth.

4/5C2.7.2 Standard Voltage TestThe insulation of all rotating machines is to be testedwith the parts completely assembled and not with theindividual parts. The dielectric strength of theinsulation is to be tested by the continuous applicationfor 60 seconds of an alternating voltage having afrequency of 25 to 60 Hz and voltage in Table 4/5C.2.

4/5C2.7.3 Direct Current TestA standard voltage test using a direct current sourceequal to 1.7 times the required alternating-currentvoltage will be acceptable.

4/5C2.9 Temperature Ratings

4/5C2.9.1 Temperature Risesa Continuous Rating Machines After the machine

has been run continuously under a rated load untilsteady temperature condition has been reached, thetemperature rises are not to exceed those given in Table4/5C.3.

b Short-time Rating Machines After the machinehas been run at a rated load during the rated time,followed by a rest and de-energized period of sufficientduration to re-establish the machine temperatureswithin 2 oC (3.6 oF) of the coolant, the temperaturerises are not to exceed those given in Table 4/5C.3. Atthe beginning of the temperature measurement,temperature of the machine is to be within 5 oC (8 oF)of the temperature of the coolant.

c Periodic Duty Rating Machines The machinehas been run at a rated load for the designed load cycleto be applied and continued until obtaining thepractically identical temperature cycle . At the middleof the period causing the greatest heating in the lastcycle of the operation, the temperature rises are not toexceed those given in Table 4/5C.3.

d Non-periodic Duty Rating Machines After themachine has been run continuously or intermittentlyunder the designed variations of the load and speedwithin the permissible operating range until reachingthe steady temperature condition, the temperature risesare not to exceed those given in Table 4/5C.3.

e Insulation Material Above 180 oC (356 oF )Temperature rises for insulation materials above 180 oC(356 oF) will be considered in accordance with4/5.13.6.

4/5C2.9.2 Ambient TemperatureThese final temperatures are based on an ambienttemperature of 50 oC (122 oF). Where provision ismade for insuring an ambient temperature beingmaintained at 40 oC (104 oF) or less, as by air coolingor by locating the machine outside of the boiler andengine rooms, the temperature rises of the windingsmaybe 10 oC (18 oF) higher. The ambient temperatureis to be taken in at least two places within 1.83 m (6 ft)


of the machine under test and by thermometers havingtheir bulbs immersed in oil contained in an open cup.

4/5C2.11 Construction and Assemblies

4/5C2.11.1 Enclosure, Frame and PedestalsMagnet frames and pedestals may be separate but are tobe secured to a common foundation.

4/5C2.11.2 Shafts and CouplingsRotating shaft, hollow shaft, and coupling flange withbolts are to comply with 4/4.19, 4/7.4 and 4/7.10 of thisGuide.

4/5C2.11.3 Circulating CurrentsMeans are to be provided to prevent circulatingcurrents from passing between the journals and thebearings, where the design and arrangement of themachine is such that damaging current may beexpected. Where such protection is required, a warningplate is to be provided in a visible place cautioningagainst the removal of such protection.

4/5C2.11.4 Rotating ExcitersRotating exciters are to conform to all applicablerequirements for generators.

4/5C2.11.5 Insulation of WindingsArmature and field coils are to be treated to resist oiland water.

4/5C2.11.6 Protection Against Cooling WaterWhere water cooling is used, the cooler is to be soarranged to avoid entry of water into the machine,whether through leakage or from condensation in theheat exchanger.

4/5C2.11.7 Moisture-condensation PreventionWhen the weight of the rotating machine, excluding theshaft, is over 455 kg (1000 lb), it is to be provided withmeans to prevent moisture condensation in the machinewhen idle. Where steam-heating coils are installed forthis purpose, there are to be no pipe joints inside thecasings. See item 7 in Table 4/5C.7 for space heaterpilot lamp for alternating-current generators.

4/5C2.11.8 Terminal ArrangementsTerminals are to be provided at an accessible positionand protected against mechanical damage andaccidental contact for earthing, short-circuit ortouching. Terminal leads are to be secured to the frameand the designation of each terminal lead are to beclearly marked. The ends of terminal leads are to befitted with connectors. Cable glands or similar are to beprovided where cable penetrations may compromise theprotection property of terminal enclosures.

4/5C2.11.9 NameplatesNameplates of corrosion-resistant material are to beprovided in an accessible position of the machine andare to indicate at least the information as listed in Table4/5C.4a.

4/5C2.13 Lubrication

Rotating machines are to have continuous lubrication atall running speeds and all normal working bearingtemperatures, with the craft's inclinations specified in4/1.21. Unless otherwise approved, where forcedlubrication is employed, the machines are to beprovided with means to shut down their prime moversautomatically upon failure of the lubricating system.Each self-lubricating sleeve bearing is to be fitted withan inspection lid and means for visual indication of oillevel or an oil gauge.

4/5C2.15 Gas Turbines for Generators

Gas-turbine prime movers driving generators are tomeet the applicable requirements in Section 4/3 of the“Rules for Building and Classing Steel Vessels Rules”and in addition are to comply with the followingrequirements.

4/5C2.15.1 Operating GovernorAn effective operating governor is to be fitted on primemovers driving main or emergency electric generatorsand is to be capable of automatically maintaining thespeed within the following limits. Special considerationwill be given when an installation requires differentcharacteristics.

a Momentary Speed Variations The momentaryspeed variations, when running at full load (equal torated output), is to be within 10% of the rated speedwhen:

1 The full load of the generator is suddenlythrown off, and

2 50% of the full load of the generator issuddenly thrown on followed by the remaining50% load after an interval sufficient to restorethe speed to steady state.

3 The speed is to return to within 1% of the finalsteady state speed in no more than 5 seconds.

b Speed Variations in Steady State The steadystate speed variation is to be within 5% of the ratedspeed at any loads between no load and the full load.

4/5C2.15.2 Overspeed GovernorIn addition to the normal operating governor anoverspeed governor is to be fitted which will trip theturbine throttle when the rated speed is exceeded bymore than 15%. Provision is to be made for handtripping. See 4/5C2.13 for pressure-lubricatedmachines.


4/5C2.15.3 Power Output of Gas TurbinesTo satisfy the requirements of 4/5A2.1. the requiredpower output of gas turbine prime movers for craft'sservice generator sets is to be based on the maximumexpected inlet air temperature.

4/5C2.17 Diesel Engines for Generators

Diesel-engine prime movers are to meet the applicablerequirements in Section 4/4 and in addition are tocomply with the following requirements.

4/5C2.17.1 Operating GovernorAn effective operating governor is to be fitted on primemovers driving main or emergency electric generatorsand is to be capable of automatically maintaining thespeed within the following limits. Special considerationwill be given when an installation requires differentcharacteristics.

a Momentary Speed Variations The momentaryspeed variations, when running at full load (equal torated output), is to be within 10% of the rated speedwhen:

1 The full load of the generator is suddenlythrown off, and

2 50% of the full load of the generator issuddenly thrown on followed by the remaining50% load after an interval sufficient to restorethe speed to steady state.

3 The speed is to return to within 1% of the finalsteady state speed in no more than 5 seconds.

4 Where the electrical power system is designedwith an associated load management system,the application of load in multiple steps of lessthan 50% of full load will be given specialconsiderations.

b Speed Variations in Steady State The steadystate speed variation is to be within 5% of the ratedspeed at any loads between no load and the full load.

4/5C2.17.2 Overspeed GovernorIn addition to the normal operating governor eachauxiliary diesel engine having a maximum continuousoutput of 220 kW and over is to be fitted with aseparate overspeed device so adjusted that the speedcannot exceed the maximum rated speed by more than15%. Provision is to be made for hand tripping. See4/5C2.13 for pressure-lubricated machines.

4/5C2.19 Alternating-current (A.C.) Generators

4/5C2.19.1 Control and Excitation of GeneratorsExcitation current for generators is to be provided byattached rotating exciters or by static exciters derivingtheir source of power from the machine being excited.

4/5C2.19.2 Voltage Regulationa Voltage Regulators A separate regulator is to be

supplied for each A.C. generator. When it is intendedthat two or more generators will be operated in parallel,reactive-droop compensating means are to be providedto divide the reactive power properly between thegenerators.

b Steady Conditions Each A.C. generator forcraft's service driven by its prime mover havinggovernor characteristics complying with 4/5C2.15.1 or4/5C2.17.1 is to be provided with an excitation systemcapable of maintaining the voltage under steadyconditions within plus or minus 2.5% of the ratedvoltage for all loads between zero and rated load atrated power factor. These limits may be increased toplus or minus 3.5% for emergency sets.

c Short Circuit Conditions Under steady-stateshort-circuit conditions, the generator together with itsexcitation system is to be capable of maintaining acurrent of not less than 3 times its rated full loadcurrent for a period of 2 seconds or of such magnitudeand duration as required to properly actuate theassociated electrical protective devices.

4/5C2.19.3 Parallel OperationFor A.C. generating sets operating in parallel, thefollowing requirements are to be complied with. Seealso 4/5A.5.5.2 for protection of A.C. generators inparallel operation.

a Reactive Load Sharing The reactive loads of theindividual generating sets are not to differ from theirproportionate share of the combined reactive load bymore than 10% of the rated reactive output of thelargest generator, or 25% of the rated reactive output ofthe smallest generator, whichever is the less.

b Load Sharing For any load between 20% and100% of the sum of the rated output (aggregate output)of all generators, the load on any generator is not todiffer more than 15% of the rated output in kilowatt ofthe largest generator or 25% of the rated output inkilowatt of the individual generator in question,whichever is the less, from its proportionate share ofthe combined load for any steady state condition. Thestarting point for the determination of the foregoingload-distribution requirements is to be at 75% of theaggregate output with each generator carrying itsproportionate share.

c Facilities for Load Adjustment Facilities are tobe provided to adjust the governor sufficiently fine topermit an adjustment of load not exceeding 5% of theaggregate output at normal frequency.


4/5C2.21 Direct-current (D.C.) Generators

4/5C2.21.1 Control and Excitation of Generatorsa Field Regulations Means are to be provided at

the switchboard to enable the voltage of each generatorto be adjusted separately. This equipment is to becapable of adjusting the voltage of the D.C. generatorto within 0.5% of the rated voltage at all loads betweenno-load and full-load.

b Polarity of Series Windings The series windingsof each generator for two wire D.C. system are to beconnected to negative terminal of each machine.

c Equalizer Connections See 4/5C4.15.3.

4/5C2.21.2 Voltage Regulationa Shunt or Stabilized Shunt-wound Generator

When the voltage has been set at full-load to its ratedvalue, the removal of the load is not to cause apermanent increase of the voltage greater than 15% ofthe rated voltage. When the voltage has been set eitherat full-load or at no-load, the voltage obtained at anyvalue of the load is not to exceed the no-load voltage.

b Compound-wound Generator Compound-wound generators are to be so designed in relation tothe governing characteristics of prime mover, that withthe generator at full-load operating temperature andstarting at 20% load with voltage within 1% of ratedvoltage, it gives at full-load a voltage within 1.5% ofrated voltage. The average of ascending anddescending voltage regulation curves between 20%load and full-load is not to vary more than 3% fromrated voltage.

c Automatic Voltage Regulators Craft's servicegenerators which are of shunt type are to be providedwith automatic voltage regulators. However, if the loadfluctuation does not interfere with the operation ofessential auxiliaries, shunt-wound generators withoutvoltage regulators or stabilized shunt-wound machinesmay be used. An automatic voltage regulators will notbe required for the craft's service generators ofapproximately flat-compounded type. Automaticvoltage regulators are to be provided for all servicegenerators driven by variable speed engines used alsofor propulsion purposes, whether these generators areof the shunt , stabilized shunt or compound-woundtype.

4/5C2.21.3 Parallel OperationFor D.C. generating sets operating in parallel, thefollowing requirements are to be complied with. Seealso 4/5A.5.7.2 for protection of D.C. generators inparallel operation.

a Stability The generating sets are to be stable inoperation at all loads from no-load to full-load.

b Load Sharing For any load between 20% and100% of the sum of the rated output (aggregate output)of all generators, the load on any generator is not todiffer more than 12% of the rated output in kilowatt of

the largest generator or 25% of the rated output inkilowatt of the individual generator in question,whichever is the less, from its proportionate share ofthe combined load for any steady state condition. Thestarting point for the determination of the foregoingload-distribution requirements is to be at 75% of theaggregate output with each generator carrying itsproportionate share.

c Tripping of Circuit Breaker D.C. generatorswhich operate in parallel are to be provided with aswitch which will trip the generator circuit breakerupon functioning of the overspeed device.

4/5C3 Accumulator Batteries

4/5C3.1 General

4/5C3.1.1 ApplicationAll accumulator batteries for engine starting, essentialor emergency services are to be constructed andinstalled in accordance with the followingrequirements. Accumulator batteries for services otherthan the above are to be constructed and equipped inaccordance with good commercial practice. Allaccumulator batteries will be accepted subject to asatisfactory performance test conducted to thesatisfaction of the Surveyor after installation.

4/5C3.1.2 Sealed Type BatteriesWhere arrangements are made for releasing gasthrough a relief valve following an overchargecondition, calculations demonstrating compliance withthe criteria in 4/5B2.7.3 under the expected rate ofhydrogen generation are to be submitted together withthe details of installation and mechanical ventilationarrangements.

4/5C3.1.3 Referencesa Emergency Services For requirements covering

emergency services and transitional source of power,see 4/5A3.5.3 and 4/5A3.7 respectively.

b Protection of Batteries For requirementscovering protection of batteries, see 4/5A5.9.

c Battery Installation For requirements coveringbattery installation, ventilation of the battery locationand protection from corrosion, see 4/5B2.7.

d Cable Installation For requirements coveringcable installation in battery room, see 4/5B3.23.

4/5C3.3 Construction and Assembly

4/5C3.3.1 Cells and Filling PlugsThe cells are to be so constructed as to prevent spillingof electrolyte due to an inclination of 40 deg. fromnormal. The filling plugs are to be so constructed as toprevent spilling of electrolyte due to craft's movementssuch as rolling and pitching.


4/5C3.3.2 Crates and TraysThe cells are to be grouped in crates or trays of rigidconstruction equipped with handles to facilitatehandling. For protection from corrosion, see 4/5B2.7.4.The mass of crates or trays are not to exceed 100 kg(220.5 lb).

4/5C3.3.3 NameplateNameplates of corrosion-resistant material are to beprovided in an accessible position of each crate or trayand are to indicate at least the information as listed inTable 4/5C.4b.

4/5C3.5 Engine-starting Battery

Battery systems for engine-starting purposes may be ofthe one-wire type and the earth lead is to be carried tothe engine frame. See also 4/4.15.9 and 4/5A3.15 formain engine starting and starting arrangement ofemergency generator, respectively.

4/5C4 Switchboards, Distribution Boards,Chargers, and Controllers

4/5C4.1 General

4/5C4.1.1 ApplicationsSwitchboards are to provide adequate control of thegeneration and distribution of electric power. Thefollowing equipment are to be constructed and tested inaccordance with the following requirements to thesatisfaction of the Surveyor.

- Switchboards and motor controllers for essentialand emergency services.- Motor control centers whose total connectedmotor rating is 100 kW or more regardless of theirservices, and- Battery chargers and discharging boards foremergency or transitional source of power.Switchboard, distribution board, charger, andcontrollers not covered by the above paragraph areto be constructed and equipped in accordance withgood commercial practice, and will be acceptedsubject to a satisfactory performance test conductedto the satisfaction of the Surveyor after installation.

4/5C4.1.2 Referencesa Inclination For requirements covering

inclination for design condition, see 4/1.21.b Emergency Switchboard For requirements

covering emergency switchboard, see 4/5A3.9.c Circuit Breakers For requirements covering

generator circuit breakers, see 4/5C6.1.d Feeder Protection For requirements covering

feeder protection, see 4/5A5.3 to 4/5A5.17, 4/5A6.3,4/5A7.1.4, and 4/5A7.3.3.

e Hull Return and Earthed Distribution SystemsFor requirements covering hull return system andearthed distribution system, see 4/5A4.3 and 4/5A4.5respectively

f Earthing For requirements covering earthingconnections, see 4/5B4.

g Installation For requirements coveringinstallation, see 4/5B2.9 for switchboard, 4/5B2.11 fordistribution boards, and 4/5B2.13 for motor controllersand control centers.

h Protection Enclosures and its Selection Forrequirements covering degree of the protection and theselection of equipment, see 4/5.15 and 4/5B2.1respectively.

4/5C4.3 Testing and Inspection

4/5C4.3.1 Applicationsa For Essential or Emergency Services All

Switchboards and motor controllers, intended foressential services or emergency services, are to betested in the presence of and inspected by the Surveyor,preferably at the plant of the manufacturer. Fordistribution boards, the tests may be carried out by themanufacturer whose certificate of tests will beacceptable and is to be submitted upon request from theBureau.

b For Non-essential or Non-emergency ServicesFor switchboards, distribution boards, and motorcontrollers of other than essential or emergencyservices, the tests may be carried out by themanufacturer whose certificate of tests will beacceptable and is to be submitted upon request from theBureau.

c Motor Control Centers All motor controlcenters, whose total connected motor rating is 100 kWor more regardless of their services, are to be tested inthe presence of and inspected by the Surveyor,preferably at the plant of the manufacturer.

d Battery Chargers and Discharging BoardWhere a battery charger and discharging board is usedfor emergency source of power or transitional source ofpower, it is to be tested in the presence of and inspectedby the Surveyor, preferably at the plant of themanufacturer. For all other battery chargers anddischarging boards, the tests may be carried out by themanufacturer whose certificate of tests will beacceptable and is to be submitted upon request from theBureau.

e Test Items Tests are to be carried out inaccordance with the requirements in Table 4/5C.5.

4/5C4.3.2 Special Testing ArrangementsIn cases where all of the required tests are not carriedout at the plant of the manufacturer, the Surveyor is tobe notified and arrangements are to be made so that theremaining tests may be witnessed.


4/5C4.5 Insulation Resistance Measurement

The insulation resistance between current-carryingparts (connected together for this purpose of this test)and earth and between current-carrying parts ofopposite polarity is to be measured at a D.C. voltage ofnot less than 500 volts before and after the dielectricstrength tests. The insulation resistance measurement,after the dielectric strength tests, is to be carried outbefore components which have been disconnected forthe dielectric tests are reconnected and the insulationresistance is not to be less than 1 megohm.

4/5C4.7 Dielectric Strength of Insulation

The dielectric strength of the insulation is to be testedfor 60 seconds by an alternating voltage applied inaccordance with Table 4/5C.5 between:

a All live parts and the interconnected exposedconductive parts, and

b Each phase and all other phases connected forthis test to the interconnected exposed conductive partsof the unit.The test voltage at the moment of application is not toexceed 50 % of the values given in Table 4/5C.5. It isto be increased steadily within a few seconds to therequired test voltage and maintained for 60 seconds.Test voltage is to have a sinusoidal waveform and afrequency between 45 Hz and 60 Hz.4/5C4.7.1 Production-line ApparatusStandard apparatus produced in large quantities forwhich the standard test voltage is 2500 volts or less,may be tested for one second with a test voltage 20%higher than the one-minute test voltage.

4/5C4.7.2 Devices with Low Insulation StrengthCertain devices such as potential transformers, havinginherently lower insulation strength are to bedisconnected during the test.


4/5C4.9.1 Enclosures and AssembliesEnclosures and assemblies are to be constructed ofsteel or other suitable incombustible, moisture-resistantmaterials and reinforced as necessary to withstand themechanical, electrical (magnetic) and thermal stresseslikely to be encountered in service and are to beprotected against corrosion. No wood is to be used,except for hardwood for nonconducting hand rails.Insulating materials are to be flame retardant andmoisture resistant. The supporting framework is to beof rigid construction.

4/5C4.9.2 Dead FrontThe dead-front type is to be used. Live-front type is notacceptable regardless of the voltage ratings.

4/5C4.9.3 Mechanical StrengthAll levers, handles, hand wheels, interlocks and theirconnecting links, shafts and bearings for the operationof switches and contactors are to be of such proportionsthat they will not be broken or distorted by manualoperation.

4/5C4.9.4 Mechanical ProtectionThe sides and the rear and, where necessary, the frontof switchboards are to be suitably guarded. Exposedlive parts having voltages to earth exceeding a voltageof 55 volts D.C. or 55 volts A.C. r.m.s. betweenconductors are not to be installed on the front of suchswitchboards. Non-conducting mats or gratings are tobe provided at the front and rear of the switchboard.Drip covers are to be provided over switchboards whensubject to damage by leaks or falling objects.

4/5C4.11 Bus Bars, Wiring and Contacts

4/5C4.11.1 DesignCopper bar is to be used for main and generator bus inthe switchboard. Other materials and combination ofmaterials will be specially considered. Generator busbars are to be designed on a basis of maximumgenerator rating. All other bus bars and bus-barconnections are to be designed for at least 75% of thecombined full-load rated currents of all apparatus theysupply, except that when they supply one unit or anygroup of units in continuous operation, they are to bedesigned for full load.

4/5C4.11.2 Operating Temperature of Bus BarsBus bars are to be proportioned to avoid temperaturewhich will affect the normal operation of electricaldevices mounted on the board.

4/5C4.11.3 Short Circuit RatingCircuit breakers and bus bars are to be mounted, bracedand located so as to withstand the thermal effects andmechanical forces resulting from the maximumprospective short circuit current. Switchboardinstruments, controls, etc., are to be located withrespect to circuit breakers so as to minimize the thermaleffects due to short circuit currents.

4/5C4.11.4 Internal WiringInstrument and control wiring is to be of the strandedtype and is to have heat-resisting and flame-retardinginsulation. Wiring from hinged panels is to be of theextra-flexible type.

4/5C4.11.5 Arrangementa Accessibility The arrangement of bus bars and

wiring on the back is to be such that all lugs are readilyaccessible.


b Locking of Connections All nuts andconnections are to be fitted with locking devices toprevent loosening due to vibration.

c Soldered Connections Soldered connections arenot to be used for connecting or terminating any wire orcable of nominal cross-sectional area of greater than2.5 mm2 (4,933 circ. mils). Soldered connections,where used, are to have a solder contact length at least1.5 times the diameter of the conductor.

4/5C4.11.6 Clearances and Creepage DistancesBare main bus bars, but not including the conductorsbetween the main bus bars and the supply side ofoutgoing units, are to have minimum clearances (in air)and creepage distances (across surfaces) in accordancewith Table 4/5C.6.

4/5C4.11.7 TerminalsTerminals or terminal rows for systems of differentvoltage are to be clearly separated each other and therated voltage is to be clearly marked. Each terminal isto have a nameplate indicating the circuit designationor circuit number.

4/5C4.13 Control and Protective Devices

4/5C4.13.1 Circuit-disconnecting Devicesa Systems Exceeding 55 Volts Distribution

boards, chargers or controllers for distribution tomotors, appliances, and lighting or other branch circuitsare to be fitted with multipole circuit breakers or amultipole switch-fuse combination in each unearthedconductor.

b Systems of 55 Volts and Less For distributionboards, chargers or controllers where voltage to earthor between poles does not exceed 55 volts D.C. or 55volts A.C. r.m.s., the fuses may be provided withoutswitches.

c Disconnect Device The rating of thedisconnecting device is to be coordinated with thevoltage and current requirements of the load. Thedisconnect device is to indicate by position of thehandle, or otherwise, whether it is open or closed.

4/5C4.13.2 Arrangement of Equipmenta Air Circuit Breakers Air circuit breaker contacts

are to be kept at least 305 mm (12 in.) from the craft'sstructure unless insulation barriers are installed.

b Voltage Regulators Voltage regulator elementsare to be provided with enclosing cases to protect themfrom damage.

c Equipment Operated in High TemperatureWhere rheostats or other devices that may operate athigh temperatures are mounted on the switchboard,they are to be naturally ventilated and so located orisolated by barriers as to prevent excessive temperatureof adjacent devices. When this cannot be

accomplished, the rheostat or other device is to bemounted separately from the switchboard.

d Accessibility to Fuses All fuses, except forinstrument and control circuits, are to be mounted on orbe accessible from the front of the switchboard.

e Protective Device for Instrumentation Allwiring on the boards for instrumentation is to beprotected by fuses or current limiting devices, see4/5A5.17.

f Wearing Parts All wearing parts are to beaccessible for inspection and readily renewable.

4/5C4.13.3 MarkingsIdentification plates are to be provided for each pieceof apparatus to indicate clearly its service.Identification plates for feeders and branch circuits areto include the circuit designation and the rating of thefuse or circuit-breaker trip setting required by thecircuit.

4/5C4.15 Switchboards

In addition to 4/5C4.1 to 4/5C4.13 as applicable, theswitchboards for essential or emergency services are tocomply with the following requirements.

4/5C4.15.1 HandrailsInsulated handrail or insulated handles are to beprovided on the front of the switchboard. Similarly,where access to the rear is required, insulated handrailor insulated handles are also to be fitted on the rear ofthe switchboard.

4/5C4.15.2 Main Bus Bar Sub-divisionWhere the total installed electrical power of the maingenerating sets is in excess of 3000 kW or theoperation of the vessel is dependent electricalequipment which is duplicate, the main bus bars are tobe subdivided into at least two parts which are to beconnected by removable links or other approvedmeans. As far as practicable, the connection ofgenerating sets and any other duplicated equipment isto be equally divided between the parts.See 4/5A4.1.1.

4/5C4.15.3 Equalizer Circuit for Direct-current(D.C.) Generators

a Equalizer Main Circuit The current rating of theequalizer main circuit for direct-current (D.C.)generators is not to be less than half of the rated full-load current of the generator.

b Equalizer Bus Bars The current rating of theequalizer bus bars is not to be less than half of the ratedfull-load current of the largest generator in the group.

4/5C4.15.4 Equipment and InstrumentationSee Table 4/5C.7


4/5C4.17 Motor Controllers and Control Centers

In addition to 4/5C4.1 to 4/5C4.13 as applicable, themotor controllers and control centers for essential oremergency services are to comply with the followingrequirements.

4/5C4.17.1 Enclosures and AssembliesThe following materials are acceptable for theenclosures.

- Cast metal, other than die-cast metal, at least 3mm (1/8 in.) thick at every point.- Nonmetallic materials which have ample strength,are noncombustible and nonabsorptive, e.g.laminated phenolic material.- Sheet metal of adequate strength.

Motor control centers are to be constructed so that theyare secured to a solid foundation, be self-supported, orbe braced to the bulkhead.

4/5C4.17.2 Disconnect Switches and CircuitBreakersCircuit-disconnecting devices are to be provided foreach motor branch circuit. For motors rated not morethan 1.5 kW and not more than 250 volts, the startingswitch may serve as a disconnect, provided it has anampere rating not less than twice the rated current ofthe motor. For motors over 1.5 kW rating thedisconnect means is to be a switch with a horsepowerrating not less than the motor rating or a circuit breakerwith an ampere rating at least 115% of motor rating.Disconnect switches and circuit breakers are to becapable of being operated without opening theenclosures in which they are installed.

4/5C4.17.3 Auto-startersAlternating-current (A.C.) motor manual auto-starterswith self-contained auto-transformers are to beprovided with switches of the quick-make-and-breaktype, and the starter is to be arranged so that it will beimpossible to throw to the running position withouthaving first thrown to the starting position. Switchesare to be preferably of the contactor or air-break-type.

4/5C4.19 Battery Chargers

In addition to 4/5C4.1 to 4/5C4.13 as applicable, thebattery chargers for essential or emergency services areto comply with the following requirements.

4/5C4.19.1 Charging CapacityExcept when a different charging rate is necessary andis specified for a particular application, the chargingfacilities are to be such that the completely dischargedbattery can be recharged to 80% capacity within aperiod of at least 10 hours.

4/5C4.19.2 Equipment and InstrumentationAt least the following equipment and instrumentationare to be provided for chargers.

a Power Supply Disconnecting Switch A switchfor disconnecting the power supply to the charger.

b Pilot Lamp A pilot lamp connected at thedownstream side of the power supply disconnectingswitch in the power supply circuit to the charger.

c Charging Voltage Adjuster A means foradjusting the voltage for charging.

d Voltmeter A voltmeter for indicating thecharging voltage to a battery. This voltmeter may alsobe used for indicating the battery discharging voltageby using a selector switch.

e Ammeter An ammeter for indicating chargingcurrent to a battery. This ammeter may also be used forindicating the battery discharging current of batteriesby using a selector switch.

f Discharge Protection An acceptable means, suchas reverse current protection, for preventing a failedbattery charger component from discharging the batteryis to be provided.

4/5C5 Transformers

4/5C5.1 General

4/5C5.1.1 ApplicationsAll transformers which serve for essential oremergency electrical supply are to be constructed andinstalled in accordance with the followingrequirements. Transformers other than the aboveservices, auto-transformers for starting motors orisolation transformers are to be constructed andequipped in accordance with good commercialpractice. All transformers are to be of the dry and aircooled type. The use of liquid immersed typetransformers will be subject to special consideration.All transformers will be accepted subject to asatisfactory performance test conducted to thesatisfaction of the Surveyor after installation.

4/5C5.1.2 Referencesa Power Supply Arrangement For requirements

covering arrangement of power supply throughtransformers to craft's service systems, see 4/5A4.1.6.

b Protection For requirements covering protectionof transformers, see 4/5A5.15.

c Protection Enclosures and its Selection Forrequirements covering selection of the protectionenclosures for location conditions, see 4/5B2.1.1.

4/5C5.1.3 Forced Cooling Arrangement (Air orLiquid) (1997)Where forced cooling medium is used to preclude thetransformer from exceeding temperatures outside itsrated range, monitoring and alarm means are to be


provided and arranged so that an alarm activates whenpre-set temperature conditions are exceeded. Manualor automatic arrangements are to be made to reduce thetransformer load to a level corresponding to the coolingavailable.

4/5C5.3 Temperature Rise

The design temperature rise of insulated windingsbased on an ambient temperature of 40 oC (104 oF) isnot to exceed the values listed in Table 4/5C.8. If theambient temperature exceeds 40 oC (104 oF), thetransformer is to be derated so that the totaltemperature based on the above temperature rises is notexceeded. Temperatures are to be taken by theresistance method of temperature determination.Temperature rises for insulation material above 180 oC(356 oF) will be considered in accordance with4/5.13.6.


4/5C5.5.1 WindingsAll transformer windings are to be treated to resistmoisture, sea atmosphere and oil vapors.

4/5C5.5.2 TerminalsTerminals are to be provided in an accessible position.The circuit designation is to be clearly marked on eachterminal connection. The terminals are to be so spacedor shielded that they can not be accidentally earthed,short-circuited or touched.

4/5C5.5.3 NameplateNameplates of corrosion-resistant material are to beprovided in an accessible position of the transformerand are to indicate at least the information as listed inTable 4/5C.4c.

4/5C6 Other Electric and Electronics Devices

4/5C6.1 Circuit Breakers

4/5C6.1.1 GeneralCircuit breakers are to be constructed and tested tocomply with IEC Publication 157-1 or other recognizedstandard. The tests may be carried out by themanufacturer whose certificate of tests will beacceptable and is to be submitted upon request from theBureau. Circuit breakers of the thermal type are to becalibrated for an ambient-air temperature as providedin 4/5.17.

Note: Where thermal-type breakers are mounted withinenclosures, it is pointed out that the temperature withinthe enclosure may exceed the designated ambient-airtemperature.

4/5C6.1.2 Mechanical PropertyArc-rupturing and main contacts of all open framecircuit breakers are to be self-cleaning.

4/5C6.1.3 IsolationThe electrical system is to be arranged so that portionsmay be isolated to remove circuit breakers whilemaintaining services necessary for propulsion andsafety of the craft, or circuit breakers are to bemounted or arranged in such a manner that the breakermay be removed from the front without disconnectingthe copper or cable connections or without de-energizing the supply to the breaker.

4/5C6.3 Fuses

Fuses are to be constructed and tested to comply withIEC Publication 269 or other recognized standard. Thetests may be carried out by the manufacturer whosecertificate of tests will be acceptable and is to besubmitted upon request from the Bureau. Allcomponents of the fuse are to be resistant to heat,mechanical stresses and corrosive influences whichmay occur in normal use.

4/5C6.5 Semiconductor Converters

4/5C6.5.1 GeneralThe requirements in this subsection are applicable tostatic converters for essential and emergency servicesusing semiconductor rectifying elements such asdiodes, reverse blocking triodes thyristors, etc. Thetests may be carried out by the manufacturer whosecertificate of tests will be acceptable and is to besubmitted upon request from the Bureau. Allsemiconductor converters will be accepted subject to asatisfactory performance test conducted to thesatisfaction of the Surveyor after installation.

4/5C6.5.2 Cooling ArrangementsSemiconductor converters are preferably to be of a dryand air cooled type. Where semiconductor convertersare of a liquid-immersed type, a liquid over-temperature alarm and gas over-pressure protectiondevices are to be provided. If provision is made forbreathing, a dehydrator is to be provided. Wherearrangement for the forced cooling is provided, thecircuit is to be designed that power cannot be appliedto, or retained, on converter stacks unless effectivecooling is maintained.

4/5C6.5.3 AccessibilitySemiconductor converter stacks or semiconductorcomponents are to be mounted in such a manner thatthey can be removed from equipment withoutdismantling the complete unit.


4/5C6.5.4 NameplateA nameplate or identification is to be provided on thesemiconductor converter and is to indicate at least theinformation as listed in Table 4/5C.4d.

4/5C6.7 Cable Junction Boxes

4/5C6.7.1 GeneralThe design and construction of the junction boxes

are to be in compliance with 4/5C6.7.2 or otherrecognized standard. The tests may be carried out bythe manufacturer whose certificate of tests will beacceptable and is to be submitted upon request from theBureau.4/5C6.7.2 Design and ConstructionLive parts are to be mounted on durable flame-retardant moisture-resistant material, of permanentlyhigh dielectric strength and high resistance. The liveparts are to be so arranged by suitable spacing orshielding with flame-retardant insulating material, thatshort-circuit cannot readily occur between conductorsof different polarity or between conductors and earthedmetal. Junction boxes are to be made of flame-retardantmaterial, junction boxes are to be clearly identifieddefining their function and voltage.

4/5C7 Cables and Wires

4/5C7.1 Cable Construction

4/5C7.1.1 GeneralElectric cables are to have conductors, insulation, andmoisture-resistant jackets in accordance with IECPublication 92-353 or IEEE Std. 45. Other recognizedmarine standards will also be considered. The tests maybe carried out by the manufacturer whose certificate oftests will be acceptable and is to be submitted uponrequest from the Bureau. Conductors are to be ofcopper and stranded in all sizes. Conductors are not tobe less than the following in cross sectional size:

- 1.0 mm2 (1,973 circ. mils) for power, lighting andcontrol cables,- 0.5 mm2 (986.5 circ. mils) for essential oremergency signaling and communications cablesexcept for those assembled by the equipmentmanufacturer, and- 0.375 mm2 (739.9 circ. mils) for telephone cablesfor non-essential communication services except forthose assembled by the equipment manufacturer.

See Table 4/5C.10 for current carrying capacity forinsulated copper wires and cables.

4/5C7.1.2 Flame Retardant Propertya Standards All electric cables are to be at least of

a flame retardant type complying with the following:- Cables constructed to IEC Publication 92standards are to comply with the flammabilitycriteria of IEC Publication 332-3.- Cables constructed to IEEE Std. 45 are to complywith the flammability criteria of that standard.- Cables constructed to another recognized marinestandard, where specially approved, are to complywith the flammability criteria of IEEE Std. 45 orother acceptable standards.

Consideration will be given to the special types ofcables such as radio frequency cable, which do notcomply with the above requirements.

b Alternative Arrangement Flame retardantmarine cables which have not passed the above-mentioned bunched cable flammability criteria maybeconsidered provided that the cable is treated withapproved flame retardant material or the installation isprovided with approved fire stop arrangements. Theflame retardancy of communications cables will bespecially considered. When specifically approved, busduct may be used in lieu of cable.

4/5C7.1.3 Fire Resistant PropertyWhen electric cables are required to be fire resistant,they are to comply with the requirements of IECPublication 331.

4/5C7.1.4 Insulation MaterialAll electrical cables for power, lighting,communication, control and electronic circuits are tohave insulation suitable for a conductor temperature ofnot less than 60 oC (140 oF). See Table 4/5C.9 for typesof cable insulation.

4/5C7.1.5 Armor for Single-conductor CablesThe armor is to be nonmagnetic for single-conductoralternating-current cables.

4/5C7.1.6 Fiber Optic CablesFiber optic cables are to be constructed and tested to arecognized fiber optic cable construction standardacceptable to the Bureau. The requirements of flameretardancy for the electrical cables is applicable to thefiber optic cables. The construction of the fiber opticcable which may pass through or enter a hazardous areais to be such that escape of gases to a safe area is notpossible through the cable.

4/5C7.3 (No text)


4/5C7.5 Portable and Flexing Electric Cables

Unless otherwise required in the Guide, cables forportable equipment and cables subject to flexingservice need not be armored.

4/5C7.7 Mineral-insulated Metal-sheathed Cable

Mineral-insulated cable provided with approved fittingsfor terminating and connecting to boxes, outlets andother equipment may be used for any service up to 600volts and may be used for feeders and branch circuits inboth exposed and concealed work, in dry or wetlocations. The moisture-resisting jacket (sheath) ofmineral-insulated metal-sheathed cable exposed tocorrosive conditions is to be made of or protected bymaterials suitable for those conditions.


Table 4/5C.1 Factory Testing Schedulefor Rotating Machines of 100 kW and over

[See 4/5C2.3.1a]

TestFirst unit of

DesignDuplicate Units Spare Rotors

A.C. D.C. A.C. D.C. A.C. or D.C.

Full-load Heat Run including Temperature RiseMeasurement

X (1) X

Saturating Curve X (2) XRunning Light Current at Rated Volts X X(2) &

(3)X (3)

Regulation Test at Operating Temperature XCold Resistance Measurement of InsulatedWindings

X X X X X

Insulated Resistance Measurement of InsulatedWindings

X X X X X

Dielectric Strength Test in accordance with Table4/5C.2

X X X X X

End Play Setting (3) X X X XBearing Temperatures X XMeasurement of Air gap X X X XCommutation Check X XRunning Balance at Rated Speed (4) X X X X XVerification of steady short circuit conditions inaccordance with 4/5C2.19.2c for A.C. Generator`(5)

X

Overload/overcurrent test in accordance with4/5C2.6

X X

Notes(1) On synchronous machine, zero power factor heat run may be taken in lieu of full-load run.(2) On synchronous machine, a no-load V curve may be taken in lieu of this test.(3) Applies only to machines supplied with complete set of bearings.(4) Static balance (machine rated 500 rpm or less) or dynamic balance (over 500 rpm) will be accepted in lieu of the specifiedtest on engine-type machines supplied without shaft and/or bearings, or with incomplete set of bearings.(5) Verification of steady short circuit condition applies to synchronous machines only.


Table 4/5C.2 Dielectric Strength Testfor Rotating Machines[See 4/5C2.7]

Item Machine or Part Test Voltage (A.C .r.m.s)

1 Insulated windings of rotating machines havingrated output less than 1 kVA, and of rated voltageless than 100 V with the exception of those in items4 to 8.

500 V + twice the rated voltage

2 Insulated windings of rotating machines havingrated output less than 10,000 kVA with theexception of those in items 1 and 4 to 8 (See Note2).

1,000 V + twice the rated voltage withminimum of 1,500 V (See Note 1)

3 Insulated windings of rotating machines havingrated output 10,000 kVA or more, and of ratedvoltage (see Note 1) up to 2,000 V with theexception of those in items 4 to 8 (see Note 2).

1,000 V + twice the rated voltage

4 Separately-excited field windings of D.C.machines.

1,000 V + twice the maximum rated circuitvoltage with minimum of 1,500 V (See Note1).

5 Field windings of synchronous generators andsynchronous motors

a) Field windings of synchronous generators Ten times the rated excitation voltage with aminimum of 1,500 V and a maximum of 3,500V.

b) When the machine is intended to be started with thefield winding short-circuited or connected across aresistance of value less than ten times the resistanceof winding.

Ten times the rated excitation voltage with aminimum of 1,500 V and a maximum of 3,500V.

c) When the machine will be started either with:- the field winding connected across resistance of more than ten times of the field winding resistance, or- the field windings on open circuit or without a field dividing switch.

1,000 V + twice the maximum value of thevoltage with a minimum of 1,500 V- between the terminals of the field winding,orbetween the terminals of any section for a sectionalized field winding,which will be occurred under the specifiedstarting conditions (see Note 3).

6 Secondary (usually rotor) windings of inductionmotors or synchronous induction motors if notpermanently short-circuited (e.g., if intended forrheostatic starting)

a) For non-reversing motors or motors reversible fromstandstill only.

1,000 V + twice the open-circuit standstillvoltage as measured between slip-rings orsecondary terminals with rated voltage appliedto the primary windings

b) For motors to be reversed or braked by reversingthe primary supply while the motor is running.

1,000 V + four times the open-circuit standstillsecondary voltage as defined in item 6.aabove.


Table 4/5C.2 Dielectric Strength Test(continued) for Rotating Machines

[See 4/5C2.7]

Item Machine or Part Test Voltage (A.C. r.m.s)

7 Exciters (except as listed below) As for windings to which they are connected.Exception 1 - Exciters of synchronous motors(including synchronous induction motors) ifconnected to earth or disconnected from the fieldwinding during starting

1,000 V + twice the rated exciter voltage with aminimum of 1,500 V.

Exception 2 - Separately excited field windings ofexciters (see Item 4 above).

8 Assembled group of machines and apparatus. A repetition of the tests in items 1 to 7 above isto be avoided if possible. But, if a test on anassembled group of several pieces of newapparatus, each one is made, the test voltage tobe applied to such assembled group is to be80% of the lowest test voltage appropriate forany part of the group (see Note 4).

Note:(1) For two-phase windings having one terminal in common, the rated voltage for the purpose of calculating the test voltageis to be taken as 1.4 times the voltage of each separate phase.(2) High-voltage tests on machines having graded insulation is to be subject to special consideration.(3) The voltage, which is occurred between the terminals of field windings or sections thereof under the specified startingconditions, may be measured at any convenient reduced supply voltage. The voltage so measured is to be increased in theratio of the specified starting supply voltage to the test supply voltage.(4) For windings of one or more machines connected together electrically, the voltage to be considered is the maximumvoltage that occurs in relation to earth.


Table 4/5C.3 Limits of Temperature Rise for Air-CooledRotating Machines[See 4/5C2.9.1]

Ambient Temperature = 50 oC (122 oF)

Temperature Class of InsulationItem Part of Machine Measuring A E B F HNo. Method (Limit of Temperature Rise in oC)

1 A.C. windings of machines havingrated output of 5,000 kVA or more, orhaving a core length of one meter ormore. 1)

Resistance

EmbeddedTemp. Detector.

50

50

60

60

70

70

90

90

115

115

2 a) A.C. windings of machines havingrated output less than 5,000 kVA orhaving a core length less than onemeter.

ThermometerResistance

4050

5565

6070

7590

95115

b) Field windings of A.C. and D.C.machines having excitation other thanthose in items 3 & 4 below.


4050

5565

6070

7590

95115

c) Windings of armatures havingcommutators.


4050

5565

6070

7590

95115

3 Field windings of turbine typemachines having D.C. excitation.

Resistance - - 80 100 -

4 a) Low-resistance field windings of morethan one layer, and compensatingwindings.


5050

6565

7070

9090

115115

b) Single-layer windings with exposedbare or varnished metal surfaces. 2)


5555

7070

8080

100100

125125

5 Permanently short-circuited insulatedwindings.

Thermometer 50 65 70 90 115

6 Permanently short-circuiteduninsulated windings.

The temperature rise of these parts isnot to reach such a value that there is

7 Magnetic core and other parts not incontact with windings.

a risk of injury to any insulating orother material on adjacent parts.

8 Magnetic core and other parts not incontact with windings.

Thermometer 50 65 70 90 115

9 Commutators and slip-rings, open orenclosed. 3)

Thermometer 50 60 70 80 90 4)

(1) The Embedded Temperature Detector method may be used in machines having outputs less than 5,000 kVA or having acore length less than one meter, but the limits of temperature rise given in this item is to be applied.

(2) Also includes multiple-layer field windings provided that the underlayers are each in contact with the circulatingcoolant.

(3) The temperature rises in item 9 are permissible provided that insulation appropriate to the temperature rise is used,except when the commutator or slip-ring is adjacent to windings in which case the temperature rise is not to exceedthat for the winding insulation class. The values of temperature rises given apply only to measurements made by bulbthermometers.

(4) Subject to special consideration in using temperature rises 90 oC (162 oF) in selection of brush grades.

See “Remark” in next page:


Table 4/5C.3 Limits of Temperature Rise for Air-Cooled(continued) Rotating Machines

[See 4/5C2.9.1]

[Remark for Table 4/5C.3](1) The limit of temperature rise in the above Table are based on an ambient temperature of 50 oC (122 oF). For 40 oC (104oF) ambient, the temperature rises may be increased 10 oC (18 oF).(2) If air-to-water heat exchangers are used, the temperature rise will be specified with respect to the temperature of thecooling water at inlet of the cooler. In this case, the temperature rise of the above Table is to be increased by 20 oC (36 oF),but only if the specified inlet water temperature does not exceed 30 oC (86 oF). When commutators of these machines arenot in the enclosed air circuit cooled by water cooler, but are cooled by the ambient cooling air, the permissible temperaturerise above the ambient cooling air is to be the same as for ventilated machine.(3) Where the machine is designed to operate with a coolant at temperature more (or less) then ambient temperature of 50oC (122 oF), the permissible temperature rises may be increased (or decreased) in accordance with the given ambienttemperature. The permissible temperature rises are to be taken to the nearest whole Celsius degrees.

[Conversion Table between Celsius (oC) and Fahrenheit (oF) for Temperature Rise]

Celsius (oC) 50 55 60 65 70 75 80 90 95 100 115 125Fahrenheit (oF) 90 99 108 117 126 135 144 162 171 180 207 225


Table 4/5C.4 Nameplates

a. Rotating Machines [See 4/5C2.11.9]The manufacturer's NameThe manufacturer's serial number (or identification mark)The year of manufactureType of Machine(Generator or motor, etc.)Degree of protection enclosures (by IP code)Class of rating or duty typeThe rated outputThe rated voltageThe rated current and type of current (A.C. or D.C.)The rated speed (r.p.m.) or speed rangeThe class of insulation or permissible temperature riseThe ambient temperature

Number of phase (for A.C. machines)The rated frequency (for A.C. machines)Power factor (for A.C. machines)Type of winding (for D.C. machines)

Exciter voltage (for synchronous machines or D.C. machines with separate excitation)Exciter current at rating (for synchronous machines or D.C. machines with separate excitation)Open-circuit voltage between slip-rings and the slip-ring current for rated conditions (for wounded-rotorinduction machines)

b. Accumulator Battery [See 4/5C3.3.3]The manufacturer's nameThe type designationThe rated voltageThe ampere-hour rating at a specific rate of dischargeThe specific gravity of the electrolyte(in the case of a lead-acid battery, the specific gravity when the battery is fully charged).

c. Transformer [See 4/5C5.5.3]The manufacturer's nameThe manufacturer's serial number (or identification mark)The year of manufactureThe number of phasesThe rated powerThe rated frequencyThe rated voltage in primary and secondary sidesThe rated current in primary and secondary sidesThe class of insulation or permissible temperature riseThe ambient temperature

d. Semiconductor Converter [See 4/5C6.5.4]The manufacturer's nameThe identification number of the equipment


Table 4/5C.5 Factory Testing Schedule for Switchboards,Chargers, Motor Control Centers,and Controllers[See 4/5C4.3.1]

(1) Insulation resistance measurements in accordance with 4/5C4.5(2) Dielectric strength test in accordance with 4/5C4.7 and the Table below(3) Protective device tripping test, such as overcurrent tripping, selective tripping, preferential tripping, etc.(4) Inspection of the assembly including inspection of wiring and, if necessary, electrical operation test.

Standard Test Voltage for Dielectric Strength Test

Rated Insulation Voltage, Dielectric Test VoltageA.C. - r.m.s

Up to and including 12 V 250 Vover 12 V to 60 V inclusive 500 V

over 60 V to 300 V inclusive 2000 Vover 300 V to 690 V inclusive 2500 Vover 690 V to 800 V inclusive 3000 V

over 800 V to 1000 V inclusive 3500 Vover 1000 V to 1500 V inclusive - *

[Note] * : For Direct-current (D.C.) only3500 V

Table 4/5C.6 Clearance and Creepage Distance forSwitchboards, Distribution boards, Chargers,Motor Control Centers and Controllers 1

[See 4/5C4.11.6]

Rated insulation voltage (V) Minimum clearances mm (in.) Minimum creepage distances mm(in.)

Up to 250 15 (19/32) 20 (25/32)From 251 to 660 20 (25/32) 30 (1 3/16)

Above 6602 25 (1) 35 (1 3/8)

[Note]1 The values in this table apply to clearances and creepage distances between live parts as well as between live parts andexposed conductive parts, including earthing.2 For 1 kV to 11 kV systems, see 4/5D1.1.4.


Table 4/5C.7 Equipment and Instrumentationfor Switchboard[See 4/5C4.15.4]

Instrumentation andEquipment

Alternating-current (A.C.) Switchboard Direct-current (D.C.) Switchboard

1. Pilot Lamp A pilot lamp for each generator connectedbetween generator and circuit breaker.See Note 3.

A pilot lamp for each generator connectedbetween generator and circuit breaker.

2. GeneratorDisconnect

A generator switch or disconnecting linksin series with the generator circuit breakerwhich is to disconnect completely allleads of the generator and the circuitbreaker from the buses except the earthlead. See Note 1.

A generator switch, or disconnectinglinks, in series with the circuit breakerwhich will open positive, negative,neutral and equalizer leads, except thatfor 3-wire generators equalizer poles maybe provided on the circuit breaker. For 3-wire generators the circuit breakers are toprotect against a short circuit on theequalizer buses. See Note 1.

3. Field Rheostat A field rheostat for each generator andeach exciter. See Note 2.

A field rheostat for each generator. SeeNote 2.

4. InsulationMonitor andAlarm

A means for continuously monitoring theelectrical insulation level to earth, and anaudible or visual alarm for abnormallylow insulation values. See Note 3.

A means for continuously monitoring theelectrical insulation level to earth, and anaudible or visual alarm for abnormallylow insulation values. See Note 3.

5. Ammeter An ammeter for each generator with aselector switch to read the current of eachphase. See Note 3.

An ammeter for each 2-wire generator.For each 3-wire generator an ammeter foreach positive and negative lead and acenter-zero ammeter in the earthconnection at the generator switchboard.Ammeters are to be so located in thecircuit as to indicate total generatorcurrent.

6. Voltmeter A voltmeter for each generator, with aselector switch to each phase of thegenerator and to one phase of the bus. SeeNote 3.

A voltmeter for each generator withvoltmeter switch for connecting thevoltmeter to indicate generator voltageand bus voltage. For each 3-wiregenerator, a voltmeter with voltmeterswitch for connecting the voltmeter toindicate generator voltage, positive tonegative, and bus voltage positive tonegative, positive to neutral, and neutralto negative. Where permanent provisionsfor shore connections are fitted, onevoltmeter switch to provide also forreading shore-connection voltage,positive to negative

7. Space HeaterPilot Lamp

Where electric heaters are provided forgenerators, a heater pilot lamp is to befitted for each generator.

Where electric heaters are provided forgenerators, a heater pilot lamp is to befitted for each generator.


Table 4/5C.7 Equipment and Instrumentation(continued) for Switchboard

[See 4/5C4.15.4]

Instrumentation andEquipment

Alternating-current (A.C.) Switchboard Direct-current (D.C.) Switchboard

8. Synchroscopeor Lamps

A synchroscope or synchronizing lampswith selector switch for paralleling in anycombination. See Note 3.

Not applicable

9. Prime moverSpeed Control

Control for prime mover speed forparalleling. See Note 3.

Not applicable

10. Wattmeter Where generators are arranged forparallel operation, an indicatingwattmeter is to be fitted for eachgenerator. See Note 3.

Not applicable

11. FrequencyMeter

A frequency meter with selector switch toconnect to any generator. See Note 3.

Not applicable

12. Field Switch A double-pole field switch with dischargeclips and resistor for each generator. SeeNote 2.

Not applicable

13. VoltageRegulator

A voltage regulator. See Note 3.

14. Stator WindingTemperatureIndicator

For alternating current generator above500 kW, a stator winding temperatureindicator is to be fitted for each generatorcontrol panel. See Notes 3 and 4.

For direct current propulsion generatorabove 500 kW, an interpole windingtemperature indicator is to be fitted foreach generator control panel. See Notes3 and 4.

[Notes](1) The switch or links may be omitted when draw-out or plug-in mounted generator breakers are furnished.(2) For generators with variable voltage exciters or rotary amplifier exciters, each controlled by voltage-regulator unit actingon the exciter field, the field switch, the discharge resistor and generator field rheostat may be omitted.(3) Where craft have centralized control systems in accordance with Section 4/11 and the generators can be paralleled fromthe main control station, this equipment may be mounted on the control console.(4) For high voltage systems, see also 4/5D1.11.1c.

Table 4/5C.8 Temperature Rise for Transformers1, 2

[See 4/5C5.3]

Insulation Class Copper Temperature Riseby Resistance

Hottest SpotTemperature Rise

Class A 55 oC(99 oF) 65 oC (117 oF)Class B 80 oC (144 oF) 110 oC (198 oF)Class F 115 oC (207 oF) 145 oC (261 oF)Class H 150 oC (270 oF) 180 oC (324 oF)

[Note]1 Metallic parts in contact with or adjacent to insulation are not to attain a temperature in excess of that allowedfor the hottest-spot copper temperature adjacent to that insulation.2 Temperature rises are based on an ambient temperature of 40C. See 4/5C5.3.


Table 4/5C.9 Types of Cable Insulation[See 4/5C7.1.4]

Insulation Type Designation Insulation Materials Maximum ConductorTemperature

V60, PVC/A Polyvinyl Chloride - General purpose

60 oC (140 oF)

V75, PVC/A Polyvinyl Chloride - Heat resisting

75 oC (167 oF)

R85, XLPE Cross-linked Polyethylene 85 oC (185 o F)E85 Ethylene Propylene Rubber 85 oC (185 oF)M95 Mineral (MI) 95 oC (203 oF) *S95 Silicone Rubber 95 oC (203 oF)

* A maximum conductor temperature of 250 oC (482 oF) is permissible for special applications and standard end fittings maybe used provided the temperature does not exceed 85 oC(185 oF) at the end of fittings. However, when the temperature at theend of fittings is higher than 85 oC (185 oF), special consideration will be given to an appropriate end fitting.


Table 4/5C.10 Maximum Current Carrying Capacity forInsulated Copper Wires and Cables[See 4/5C7.1.1]

Values in amperes45oC (113oF) Ambient750V and Less (A.C. or D.C.)

Conductor Size 1/C TYPE 2/C TYPE 3-4/C TYPE

mm2

103

circmils

V60PVC/A60oC

(140oF)

V75,Heat

Resist.PVC75oC

(167oF)

R85,XLPE,

E8585oC

(185oF)

M95,S9595oC

(203oF)

V60PVC/A60oC

(140oF)

V75,Heat

Resist.PVC75oC

(167oF)

R85,XLPE,

E8585oC

(185oF)

M95,S95

95oC(203oF)

V60PVC/A60oC

(140oF)

V75,Heat

Resist.PVC75oC

(167oF)

R85,XLPE,

E8585oC(185oF)

M95,S95

95oC(203oF)

625 755 894 1006 642 760 855 529 626 704600 736 872 981 626 741 834 515 610 687

1000 662 784 882 563 666 750 463 549 617500 656 778 875 558 661 744 459 545 613

950 641 760 854 545 646 726 449 532 598900 620 734 826 527 624 702 434 514 578850 598 709 797 508 603 677 419 496 558800 576 682 767 490 580 652 403 477 540

400 571 677 761 485 575 647 400 474 533750 553 655 737 470 557 626 387 459 516700 529 628 706 450 534 600 370 440 494650 506 599 674 430 509 573 354 419 472600 481 570 641 409 485 545 337 399 449

300 335 477 565 636 285 405 480 541 235 334 396 445550 455 540 607 387 459 516 319 378 425500 429 509 572 365 433 486 300 356 400

240 290 415 492 553 247 353 418 470 203 291 344 387450 402 476 536 342 405 456 281 333 375400 373 442 498 317 376 423 261 309 349

185 250 353 418 470 213 300 355 400 175 247 293 329350 343 407 458 292 346 389 240 285 321300 312 370 416 265 315 354 218 259 291

150 220 309 367 412 187 263 312 350 154 216 257 288250 278 330 371 236 281 315 195 231 260

120 190 269 319 359 162 229 271 305 133 188 223 251212 251 297 335 213 252 285 176 208 235

95 165 232 276 310 140 197 235 264 116 162 193 217168 217 257 289 184 218 246 152 180 202

70 135 192 228 256 115 163 194 218 95 134 160 179133 188 222 250 160 189 213 132 155 175106 163 193 217 139 164 184 114 135 152

50 105 156 184 208 89 133 156 177 74 109 129 14683.7 140 166 187 119 141 159 98 116 131

35 87 125 148 166 74 106 126 141 61 88 104 11666.4 121 144 162 103 122 138 85 101 113


Table 4/5C.10 Maximum Current Carrying Capacity for(continued) Insulated Copper Wires and Cables

[See 4/5C7.1.1]

Values in amperes45oC (113oF) Ambient750V and Less (A.C. or D.C.)

Conductor Size 1/C TYPE 2/C TYPE 3-4/C TYPE

mm2

103

circmils

V60PVC/A60oC

(140oF)

V75,Heat

Resist.PVC75oC

(167oF)

R85,XLPE,

E8585oC

(185oF)

M95,S9595oC

(203oF)

V60PVC/A60oC

(140oF)

V75,Heat

Resist.PVC75oC

(167oF)

R85,XLPE,

E8585oC

(185oF)

M95,S95

95oC(203oF)

V60PVC/A60oC

(140oF)

V75,Heat

Resist.PVC75oC

(167oF)

R85,XLPE,

E8585oC(185oF)

M95,S95

95oC(203oF)

52.6 105 124 140 89 105 119 74 87 9825 71 101 120 135 60 86 102 115 50 71 84 95

41.7 91 108 121 77 92 103 64 76 8533.1 79 93 105 67 79 89 55 65 74

16 54 76 91 102 46 65 77 87 38 53 64 7126.3 68 81 91 58 69 77 48 57 6420.8 59 70 78 50 60 66 41 49 55

10 40 57 67 76 34 48 57 65 28 40 47 5316.5 51 60 68 43 51 58 36 42 48

6 29 41 49 55 25 35 42 47 20 29 34 3910.4 38 45 51 32 38 43 27 32 36

4 22 32 38 43 19 27 32 37 15 22 27 306.53 28 34 38 24 29 32 20 24 27

2.5 17 24 28 32 14 20 24 27 12 17 20 224.11 21 25 32 18 21 27 15 18 22

1.5 12 17 21 26 10 14 18 22 8 12 15 181.25 15 18 23 13 15 20 11 13 16

1.0 8 13 16 20 7 11 14 17 6 9 11 14

[Notes](1) The values give above have been calculated for an ambient of 45 oC (113 oF) and assume that a conductor temperatureequal to the maximum rated temperature of the insulation is reached and maintained continuously in the case of a group offour cables bunched together and laid in free air.(2) The current rating values give in Table 4/5.C10 (and those derived therefrom) may be considered applicable, withoutcorrection factors, in cable conduits or cable pipes, except as noted in Note 3.(3) For bunched cables, see 4/5B3.11.1(4) These current ratings are applicable for both armored and unarmored cables.(5) If ambient temperature differs from 45 oC (113 oF), the values in Table 4/5.C10 are to be multiplied by the followingfactors.

MaximumConductor

TemperatureAmbient Correction Factor

40oC (104oF) 50oC (122oF) 55oC (131oF) 60oC (140oF) 65oC (149oF) 70oC (158oF)

60oC (140oF) 1.15 0.82 -- -- -- --

75oC (167oF) 1.08 0.91 0.82 0.71 0.58 ---


MaximumConductor

TemperatureAmbient Correction Factor

40oC (104oF) 50oC (122oF) 55oC (131oF) 60oC (140oF) 65oC (149oF) 70oC (158oF)

80oC (176oF) 1.07 0.93 0.85 0.76 0.65 0.53

85oC (185oF) 1.06 0.94 0.87 0.79 0.71 0.61

95oC (203oF) 1.05 0.95 0.89 0.84 0.77 0.71

(6) Where the number of conductors in a cable exceeds 4,, as in control cables, the maximum current carrying capacity ofeach conductor is to be reduced as in the following table.

No. of Conductors % of 3-4/C TYPE Values in Table 4/5.C10

5 - 6 80

7 - 24 70

25 - 42 60

43 and above 50

(7) When a mineral-insulated cable is installed in such a location that its copper sheath is liable to be touched when inservice, the current rating is to be multiplied by the correction factor 0.80 in order that the sheath temperature does notexceed 70 oC (158 oF). (8) Cables being accepted based on approved alternate standard may have current carrying capacity of that standard providedthe cables are in full compliance with that standard.

PART 4 SECTION 5|59 Electrical Installations -- Part D. Specialized Installations

Part D. SpecializedInstallations

4/5D1 High Voltage Systems

4/5D1.1 General

4/5D1.1.1 ApplicationThe following requirements in this sub-section areapplicable to systems with nominal voltage (phase tophase) exceeding 1 kV and up to 11 kV. For systemswith nominal voltages exceeding 11 kV a recognizedstandard will be considered. Unless stated otherwise,high voltage equipment and systems are to complywith the other parts in Section 4/5 for low voltageequipment and systems as well.

4/5D1.1.2 Standard Voltages and FrequencyThe nominal standard voltages/frequenciesrecommended are 3.0 kV, 3.3 kV, 6.0 kV, 6.6 kV, 10kV and 11 kV at 50 or 60 hertz. Othervoltage/frequencies in accordance with a recognizednational standard will be considered provided thatthe entire system is designed to that standard.

4/5D1.1.3 Distribution SystemsThe following distribution systems can be used:

- 3 phase 3 wire with insulated neutral, or- 3 phase 3 wire with earthed neutral.

Earthed neutral systems are permitted only outsidehazardous areas.

4/5D1.1.4 Air Clearance and Creepage Distancea Air Clearance Phase-to-phase air clearances

and phase-to-earth air clearances between non-insulated parts are to be not less than the minimum asspecified below.

Nominal Voltage in kV Minimum airclearance in mm (in.)

1 - 1.1 25 (1.0)3 - 3.3 55 (2.2)6 - 6.6 90 (3.6)10 - 11 120 (4.8)

Where intermediate values of nominal voltages areaccepted, the next higher air clearance is to beobserved. Where necessary, these distances are to beincreased to allow for the electromagnetic forcesinvolved. In the case of smaller distances,appropriate voltage impulse test is to be applied.

b Creepage Distance Creepage distancesbetween live parts and between live parts and earthedmetal parts are to be adequate for the nominal voltageof the system, due regard being paid to thecomparative tracking index of insulating materialsunder moist conditions according to the IECPublication 112 and to the transient overvoltagedeveloped by switching and fault conditions.

4/5D1.3 System Design

4/5D1.3.1 Selective CoordinationSelective coordination is to be in accordance with4/5A5.1.5, regardless of the system neutral earthingarrangement.

4/5D1.3.2 Earthed Neutral Systemsa Current Due to Earth Fault Whatever the

earthing method (resistor or other limiting device), incase of an earth fault the current is not to be greaterthan the full load current of the largest generator onthe switchboard but not less than three times theminimum current required to operate any deviceagainst an earth fault.

b Equipment Electrical equipment is towithstand the earth fault current for the timenecessary to trip the protective device.

c Other Standard or Code Special considerationwill be given to directly earthed neutral or otherproposed earth neutral systems designed to otherrecognized standards or code of practices.

4/5D1.3.3 Neutral DisconnectionEach generator neutral is to be provided with meansfor disconnection.

4/5D1.3.4 Hull Connection of Earthing ResistorsAll earthing resistors are to be connected to the hull.Neutral earth resistors or devices are to beindividually connected to the hull and also bonded toeach other. Additionally, the earth resistors or devicesfor connection of the neutrals to the hull are to beprovided for each section of the system.

4/5D1.3.5 Interconnection of NeutralsGenerators running in parallel may have a commonneutral conductor to earth provided the thirdharmonic content of the wave form is 5% or less.Otherwise, individual resistors are to be provided forneutral connection to earth of each generator.

4/5D1.3.6 Earth Fault DetectionAn earth fault is to be indicated by visual and audiblemeans. Rapid isolation is to be provided unless thesystem is designed to operate continuously with anearth fault.


4/5D1.5 Auxiliary Systems

4/5D1.5.1 Source of SupplyWhere electrical energy or mechanical energy isrequired for the operation of circuit breakers andswitches, a means of storing such energy is to beprovided with a capacity at least sufficient for twoon/off operation cycles of all the components.However, the tripping due to overload or short-circuit, and under-voltage is to be independent of anystored electrical energy sources. This does notpreclude shunt tripping

4/5D1.5.2 Number of Supply SourcesAt least one independent source of supply forauxiliary circuits of each independent section of thesystem is to be provided.

4/5D1.7 Protection

4/5D1.7.1 GeneratorProtection against interwinding faults within thegenerator is to be provided. This is to trip thegenerator circuit breaker and de-excite the generator.

4/5D1.7.2 Power TransformersIf the total connected load of all outgoing circuits ofthe power transformer secondary side exceeds therated load, an overload protection or an overloadalarm is to be fitted. When transformers areconnected in parallel, tripping of the protectivedevices at the primary side is to automatically trip theswitch or protective devices connected at thesecondary side.

4/5D1.7.3 Voltage Transformers for Control andInstrumentationVoltage transformers are to be protected againstshort-circuit by fuses on the primary and secondarysides. Special consideration will be given to omittingfuses on the primary side or to fitting automaticcircuit breakers on the secondary side instead offuses.

4/5D1.7.4 FusesFuses may be used for short-circuit protection but notfor overload protection.

4/5D1.7.5 Low Voltage SystemsLower voltage systems supplied through transformersfrom high voltage systems are to be protected againstovervoltages due to loss of insulation betweenprimary and secondary windings. Direct earthing ofthe lower voltage system or appropriate neutralvoltage limiters may be fitted. Special considerationwill be given to the use of an earthed screen betweenthe primary and secondary windings of high voltagetransformers.

4/5D1.9 Equipment Installation and Arrangement

4/5D1.9.1 Degree of ProtectionThe degree of equipment protection is to be inaccordance with Table 4/5B.1.

4/5D1.9.2 Protective Arrangementsa Interlocking Arrangements Where high-

voltage equipment is not contained in an enclosurebut a room forms the enclosure of the equipment, theaccess doors are to be so interlocked that they cannotbe opened until the supply is isolated and theequipment earthed down.

b Warning Plate At the entrance of such spaces,a suitable marking is to be placed which indicatesdanger of high-voltage and the maximum voltageinside the space. For high-voltage electricalequipment installed outside these spaces, a similarmarking is to be provided.

4/5D1.9.3 Cablesa Runs of Cables High voltage cables are not to

be run through accommodation spaces. If notpracticable, special consideration will be given tosuch installation.

b Segregation High voltage cables are to besegregated from cables operating at lower voltages; inparticular, they are not to be run either in the samecable bunch, the same ducts or pipes, or, in the samebox. Other suitable equivalent arrangement may beaccepted.Higher voltage equipment are not to be combinedwith lower voltage equipment in the same enclosure,unless segregation or other suitable measures aretaken to ensure safe access to lower voltageequipment.

c Installation Arrangements High voltagecables, are to be installed on cable trays or equivalentwhen they are provided with a continuous metallicsheath or armor which is effectively bonded to earth;otherwise they are to be installed for their entirelength in metallic ducting or pipes effectively bondedto earth.

d Termination and Splices Terminations in allconductors of high voltage cables are to be, as far aspracticable, effectively covered with suitableinsulating material. In terminal boxes, if conductorsare not insulated, phases are to be separated fromearth and from each other by substantial barriers ofsuitable insulating materials. Precautions are to betaken to relieve the electrical stresses where cableinsulation is terminated. Terminations and splices areto be of a type compatible with the insulation andjacket material of the cable and are to be providedwith means to earth all metallic shielding components(i.e. tapes, wires, etc.)

e Marking High voltage cables are to be readilyidentifiable by suitable marking.


f Test after Installation After installation, highvoltage cables are to be subjected to a voltage testwith a D.C. voltage of 4 times the rated phase to earthvoltage (Uo) applied for 15 minutes.

4/5D1.11 Machinery and Equipment

4/5D1.11.1 Rotating Machinesa Protection Rotating machines are to have a

degree of protection of at least IP23; for terminal box,IP44, and for motors accessible to unqualifiedpersonnel, IP43.

b Windings Generator stator windings shouldhave all phase ends brought out.

c Temperature Detectors Rotating machines areto be provided with temperature detectors in theirstator windings to actuate a visual and audible alarmin a normally attended position whenever thetemperature exceeds the permissible limit. Ifembedded temperature detectors are used, means areto be provided to protect the circuit againstovervoltage.

d Cooler Water-air heater exchangers of rotatingmachines are to be of the double tube type. In anormally attended position a visual and audible alarmis to be given to monitor water cooler leakage.

e Space Heater Effective means are to beprovided to prevent the accumulation of moisture andcondensation within the machines when they are idle.

f Tests A high voltage test is to be carried outon the individual coils in order to demonstrate asatisfactory withstand level of the interwinding turninsulation to steep fronted switching surges. This testapplies to coils for rotating machines to be used foreither earth or insulated systems. The peak testvoltage is to be that calculated by: Vt = 2.45V,where V is the nominal voltage of the system. Eachcoil is to be subject to at least five impulses.Alternative procedures recommended by themanufacturer will be considered.4/5D1.11.2 Switchgear and ControlgearAssembliesSwitchgear and controlgear assemblies are to beconstructed according to the IEC Publication 298 andthe following additional requirements:

a Protection Switchgear, controlgear assembliesand converters are to have a degree of protection of atleast IP23.

b Mechanical Construction Switchgear shouldbe of metal - enclosed type in accordance with IECPublication 298 or of the insulation - enclosed type inaccordance with IEC Publication 466.

c Configuration The distribution switchboard isto be divided in accordance with 4/5C4.15.2;however, the main bus bars are to be connected bycircuit breakers, switches or switch disconnectors.

d Clearance and Creepage Distances Forclearance and creepage distances, see 4/5D1.1.4.

e Circuit Breakers Circuit breakers are to be ofthe withdrawable type or fitted with equivalent meansor arrangements permitting safe disconnection whilstthe bus bars are live.

f Locking Facilities Withdrawable circuitbreakers and switches are to be provided withmechanical locking facilities in both service anddisconnected positions. For maintenance purposes,key locking of withdrawable circuit breakers,switches and fixed disconnectors are to be possible.Withdrawable circuit breakers when in the serviceposition are to have no relative motion between fixedand moving parts.

g Shutters The fixed contacts of withdrawablecircuit breakers and switches are to be so arrangedthat in the withdrawable position the live contacts areautomatically covered.

h Earthing and Short-circuiting Formaintenance purposes, an adequate number ofearthing and short-circuiting devices is to be providedto enable circuits to be worked upon with safety.

i Tests A power frequency voltage test is to becarried out on high voltage switchgear andcontrolgear assemblies using the following testvoltages in accordance with the procedures of IECPublication 298 or other equivalent standards.

Nominal Voltage (phaseto phase) (kV)

Test Voltage (kV)

2.5 - 3.6 103.6 - 7.2 207.2 - 11 28

Nominal voltage exceeding 1 kV up to voltagesbelow 2.5 kV will be specially considered.4/5D1.11.3 Transformers

a Protection Transformers are to have a degreeof protection of at least IP44. However, wheninstalled in spaces accessible to qualified personnelonly the degree of protection may be reduced toIP2X. For transformers not contained in enclosures,see 4/5D1.9.1.

b Condensation Effective means to preventaccumulation of moisture and condensation within thetransformers (when de-energized) is to be provided.

4/5D1.11.4 Miscellaneous EquipmentEquipment is to comply with the following IECPublication or other recognized standards:

1 Circuit Breakers IEC 562 Switches IEC 2653 Fuses IEC 2824 Contactors IEC 4705 Current Transformers IEC 1856 Voltage Transformers IEC 1867 Relay IEC 255


4/5D1.11.5 Cablesa Standards Cables are to be constructed to IEC

Publication 92-3, 92-354, or other equivalentrecognized standard. See also 4/5C7.1

b Rated Voltage In a system with insulatedneutral, the rated phase to earth voltage (Uo) of thecables is to be not less than the nominal voltage of thesystem. For an earth neutral system, the rated phaseto phase voltage (Un) is to be not less than thenominal voltage of the system. See IEC Publication183.

4/5D2 Electric Propulsion System

4/5D2.1 Application

The following requirements in this sub-section areapplicable to electric propulsion system. The electricpropulsion system complying with other recognizedstandard will be considered. Unless stated otherwise,electric propulsion equipment and systems are tocomply with the applicable requirements in otherparts of Section 4/5 as well.

4/5D2.3 Plans and Data to be Submitted

In addition to the plans and data to be submitted inaccordance with 4/5A1, 4/5B1, and 4/5C1, thefollowing plans and data are to be submitted forreview.

- One line diagrams of propulsion control systemfor power supply, circuit protection, alarm,monitoring, safety and emergency shutdownsystems including list of alarm and monitoringpoints.- Plans showing the location of propulsioncontrols and its monitoring stations.- Arrangements and details of the propulsioncontrol console or panel including schematicdiagram of the system therein.- Arrangements and details of electric coupling.- Arrangements and details of the semiconductorconverters enclosure for propulsion systemincluding data for semiconductor converter,cooling system with its interlocking arrangement.

4/5D2.5 Propulsion Power Supply Systems

4/5D2.5.1 Propulsion Generatorsa Power Supply The power for the propulsion

equipment may be derived from a single generator. Ifa craft service generator is also used for propulsionpurposes, other than for boosting the propulsionpower, such generator and power supply circuits topropulsion systems are also to comply with theapplicable requirements in this subsection. See also4/5A2.1.4.

b Single System If a propulsion system containsonly one generator and one motor and cannot beconnected to another propulsion system, more thanone exciter set is to be provided for each machine.However, this is not necessary for self-exitedgenerators or for multi-propeller propulsion craftwhere any additional exciter set may be common forthe craft.

c Multiple Systems Systems having two or morepropulsion generators, two or more semiconductorconverters, or two or more motors on one propellershaft are to be so arranged that any unit may be takenout of service and disconnected electrically withoutpreventing the operation of the remaining units.

d Excitation Systems Arrangements for electricpropulsion generators are to be such that propulsioncan be maintained in case of failure of an excitationsystem or failure of a power supply for an excitationsystem. Propulsion may be at reduced power undersuch conditions where two or more propulsiongenerators are installed provided such reduced poweris sufficient to provide for a speed of not less than 7knots or 1/2 of design speed whichever is the lesser.

e Features for Other Services If the propulsiongenerator is used for other purposes than forpropulsion, such as dredging, and other specialservices, overload protection in the auxiliary circuitand means for making voltage adjustments are to beprovided at the control board. When propulsionalternating-current generators are used for otherservices for operation in port, the port excitationcontrol is to be provided with a device that is tooperate just below normal idling speed of thegenerator to remove excitation automatically.

4/5D2.5.2 Propulsion Excitationa Excitation Circuits Every exciter set is to be

supplied by a separate feeder. Excitation circuits arenot to be fitted with overload circuit-interruptingdevices except those intended to function inconnection with the protection for the propulsiongenerator. In such cases the field circuit breaker is tobe provided with a discharge resistor unless apermanent discharge resistor is provided.

b Field Circuits Field circuits is to be providedwith means for suppressing voltage rise when a fieldswitch is opened. Where fuses are used for excitationcircuit protection it is essential that they do notinterrupt the field discharge resistor circuit uponrupturing.

c Craft's Service Generator Connection Wherethe excitation supply is obtained from the ship'sservice generators, the connection is to be made to thegenerator side of the generator circuit breaker withthe excitation supply passing through the overloadcurrent device of the breaker.


4/5D2.5.3 Semiconductor ConvertersSemiconductor converter circuits are to be able towithstand the transient overcurrents to which thesystem is subject during maneuvering. Wheresemiconductor converters are connected in parallel,the current for each semiconductor converters is to beequally distributed as far as practicable. If severalelements are connected in parallel and a separate fanis fitted for each parallel branch, arrangements are tobe made for disconnecting the circuit for whichventilation is not available. Where semiconductorconverters are connected in series, the voltagebetween the semiconductor devices are to be equallydistributed as far as practicable. In case of failure ofthe cooling system, an alarm is to be given or thecurrent is to be reduced automatically.

4/5D2.7 Circuit Protection

4/5D2.7.1 SettingOvercurrent protective devices, if any, in the maincircuits are to be set sufficiently high so as not tooperate on overcurrents caused by maneuvering ornormal operation in heavy seas or in floating brokenice.

4/5D2.7.2 Direct-current (D.C.) PropulsionCircuits

a Circuit Protection Direct-current propulsioncircuits are not to have fuses. Each circuit is to beprotected by overload relays to open the field circuitsor by remote-controlled main-circuit interruptingdevices. Provision is to be made for closing circuitbreakers promptly after opening.

b Protection for Reversal of the RotationWhere separately driven D.C. generators areconnected electrically in series, means shall beprovided to prevent reversal of the rotation of agenerator upon failure of the driving power of itsprime mover.

4/5D2.7.3 Excitation CircuitsAn overload protection is not to be provided foropening of the excitation circuit.

4/5D2.7.4 Reduction of Magnetic FluxesMeans are to be provided for selective tripping orrapid reduction of the magnetic fluxes of thegenerators and motors so that overcurrents do notreach values which may endanger the plant.

4/5D2.7.5 Semiconductor Convertersa Overvoltage Protection Means are to be

provided to prevent excessive overvoltages in asupply system to which converters are connected.Visual and audible alarm are to be provided at thecontrol station for tripping of the protective fuses forthese devices.

b Overcurrent Protection Arrangements are tobe made so that the permissible current ofsemiconductor elements cannot be exceeded duringnormal operation.

c Short-circuit Protection Fuses are to beprovided for protection of short-circuit ofsemiconductor converters. Visual and audible alarmare to be provided at the control station for tripping ofthese semiconductor protective fuses. In case ofblown fuse, the respective part of the plants is to betaken out of operation.

d Filter Circuits Fuses are to be provided forfilter circuits. Visual and audible alarm are to beprovided at the control station for tripping of the fuse.

4/5D2.9 Protection for Earth Leakage

4/5D2.9.1 Main Propulsion CircuitsMeans for earth leakage detection are to be providedfor the main propulsion circuit and be arranged tooperate an alarm upon the occurrence of an earthfault. When the fault current flowing is liable to causedamage, arrangements for opening the mainpropulsion circuit are also to be provided.

4/5D2.9.2 Excitation CircuitsMeans are to be provided for earth leakage detectionin excitation circuits of propulsion machines but maybe omitted in circuits of brushless excitation systemsand of machines rated up to 500 kW.

4/5D2.9.3 Alternating-current (A.C.) SystemsAlternating-current propulsion circuits are to beprovided with an earthing detector alarm or indicator.If the neutral is earthed for this purpose, it is to bethrough an arrangement which will limit the current atfull-rated voltage so that it will not exceedapproximately 20 amperes upon a fault to earth in thepropulsion system. An unbalance relay is to beprovided which is to open the generator and motor-field circuits upon the occurrence of an appreciableunbalanced fault.

4/5D2.9.4 Direct-current (D.C.) SystemsThe earthing detector may consist of a voltmeter orlights. Provision is to be made for protection againstsevere overloads, excessive currents and electricalfaults likely to result in damage to the plant.Protective equipment is to be capable of being so setas not to operate on the overloads or overcurrentsexperienced in a heavy seaway or when maneuvering.

4/5D2.11 Electric Propulsion Control

4/5D2.11.1 GeneralFailure of a control signal is not to cause an excessiveincrease in propeller speed. The reference valuetransmitters in the control stations and the control


equipment are to be so designed that any defect in thedesired value transmitters or in the cables between thecontrol station and the propulsion system will notcause a substantial increase in the propeller speed.

4/5D2.11.2 Automatic and Remote ControlSystemsWhere two or more control stations are providedoutside the engine room, or where automatic controlof the propulsion machinery is provided, 4/11.1

through 4/11.7, as applicable, are to be compliedwith. See 4/11.1.2 for propulsion class symbols.

4/5D2.11.3 Testing and InspectionControls for electric propulsion equipment are to beinspected when finished and dielectric strength testsand insulation resistance measurements made on thevarious circuits in the presence of the Surveyor,preferably at the plant of manufacture. Thesatisfactory tripping and operation of all relays,contactors and the various safety devices are also tobe demonstrated.

4/5D2.11.4 Initiation of ControlThe control of the propulsion system can be activatedonly when the delegated control lever is in zeroposition and the system is ready for operation.

4/5D2.11.5 Emergency StopEach control station shall have an emergency stopdevice which is independent of the control lever.

4/5D2.11.6 Prime Mover ControlWhere required by the system of control, means areto be provided at the control assembly for controllingthe prime mover speed and for mechanically trippingthe throttle valve.

4/5D2.11.7 Control Power FailureIf failure of the power supply occurs in systems withpower-aided control (e.g. with electric, pneumatic orhydraulic aid), it is to be possible to restore control ina short time.

4/5D2.11.8 ProtectionArrangements are to be made so that opening of thecontrol system assemblies or compartments will notcause inadvertent or automatic loss of propulsion.Where steam and oil gauges are mounted on themain-control assembly, provision is to be made sothat the steam or oil will not come in contact with theenergized parts in case of leakage.

4/5D2.11.9 InterlocksAll levers for operating contactors, line switches,field switches and similar devices are to beinterlocked to prevent their improper operation.

Interlocks are to be provided with the field lever toprevent the opening of any main circuits without firstreducing the field excitation to zero, except that whenthe generators simultaneously supply power to anauxiliary load apart from the propulsion, the fieldexcitation need only be reduced to a low value.

4/5D2.13 Instrumentation at the Control Station

4/5D2.13.1 Indication, Display and AlarmsThe necessary instruments to indicate existingconditions at all times are to be provided andmounted on the control panel convenient to theoperating levers and switches. Instruments and otherdevices mounted on the switchboard are to be labeledand the instruments provided with a distinguishingmark to indicate full-load conditions. Metallic casesof all permanently installed instruments are to bepermanently earthed. The following instruments,where applicable, are to be provided.

a For A-C Systems Ammeter, voltmeter,indicating wattmeter and field ammeter(*) for eachpropulsion generator and for each synchronousmotor. See also Table 4/11.7.

b For D-C Systems An ammeter for each maincircuit and one or more voltmeters with selectorswitches for reading voltage on each propulsiongenerator and motor. See also Table 4/11.7.

c For Electric Slip Couplings An ammeter forthe coupling excitation circuit.

* Field ammeter is not required for brushless generators.

4/5D2.13.2 Indication of Propulsion System StatusThe control stations of the propulsion systems are tohave at least the following indications for eachpropeller.

a "Ready for Operation" Power circuits andnecessary auxiliaries are in operation.

b "Faulty" Propeller is not controllable.c "Power Limitation" In case of disturbance,

for example, in the ventilators for propulsion motors,in the converters, cooling water supply or loadlimitation of the generators.

4/5D2.15 Equipment Installation andArrangement

4/5D2.15.1 GeneralThe arrangement of bus bars and wiring on the backof propulsion-control assemblies is to be such that allparts, including the connections, are accessible. Allnuts and connections are to be fitted with lockingdevices to prevent loosening due to vibration.Clearance and creepage distance are to be providedbetween parts of opposite polarity and between liveparts and earth to prevent arcing. See 4/5.19,4/5C4.11.6, and 4/5D1.11.2d.


4/5D2.15.2 Accessibility and Facilities for Repairsa Accessibility For purposes of inspection and

repair, provision is to be made for access to the statorand rotor coils, and for the withdrawal andreplacement of field coils. Adequate access is to beprovided to permit resurfacing of commutators andslip-rings, as well as the renewal and bedding ofbrushes.

b Facility for Supporting Facilities shall beprovided for supporting the shaft to permit inspectionand withdrawal of bearings.

c Slip-couplings Slip-couplings are to bedesigned to permit removal as a unit without axialdisplacement of the driving and driven shaft, andwithout removing the poles.

4/5D2.15.3 Semiconductor ConvertersConverters are to be installed away from sources ofradiant energy in locations where the circulation ofair is not restricted to and from the converter andwhere the temperature of the inlet air to air-cooledconverters will not exceed that for which theconverter is designed. Immersed-type converters areto use a non-flammable liquid. Where forced coolingis utilized, the circuit is to be so designed that powercannot be applied to or retained on converters unlesseffective cooling is maintained. Converter stacks areto have at least IP22 protection and mounted in sucha manner that they may be removed withoutdismantling the complete unit.

4/5D2.15.4 Propulsion CablesPropulsion cables are not to have splices or jointsexcept terminal joints and all cable terminals are to besealed against the admission of moisture or air.Similar precautions are to be taken during installationby sealing all cable ends until the terminals arepermanently attached. Cable supports are to bedesigned to withstand short- circuited conditions.They are to be spaced less than 915 mm (36 in.) apartand are to be arranged to prevent chafing of the cable.See 4/5B3.9.1.

4/5D2.17 Machinery and Equipment

4/5D2.17.1 Material TestsThe following materials intended for main propulsioninstallation are to be tested in accordance with the“ABS Requirements for Materials and Welding”:thrust shafts, line shafts, propeller shafts, shafting forpropulsion generators and motors, coupling bolts, andin the case of direct-connected turbine-drivenpropulsion generators, fan shrouds, centering andretaining rings. Major castings or built-up parts suchas frames, spiders and end shields are to be surfaceinspected and the welding is to be in accordance withthe “ABS Requirements for Materials and Welding ”.

4/5D2.17.2 Temperature RatingWhen generators, motors or slip-couplings forelectric propulsion are fitted with an integral fan andwill be operated at speeds below the rated speed withfull-load torque, full-load current, or full-loadexcitation temperature rise limits according to Table4/5C.3 are not to be exceeded.

4/5D2.17.3 Protection Against MoistureCondensation4/5C2.11.7 is applicable for rotating machines andconverters regardless of the weight of the machines.

4/5D2.17.4 Prime Moversa Capability The prime mover rated output are

to have adequate overloading and build-up capacityfor supplying the power which is necessary duringtransitional changes in operating conditions of theelectrical equipment. When maneuvering from fullpropeller speed ahead to full propeller speed asternwith the craft making full way ahead, the primemover is be capable of absorbing a proportion of theregenerated power without tripping due to overspeed.

b Speed Control Prime movers of any type areto be provided with a governor capable ofmaintaining the pre-set steady speed within a rangenot exceeding 5% of the rated full-load speed for loadchanges from full-load to no-load.

c Manual Controls Where the speed control ofthe propeller requires speed variation of the primemover, the governor is to be provided with means forlocal manual control as well as for remote control.For turbines driving A.C. propulsion generators,where required by the system of control, the governoris to be provided with means for local hand control aswell as remote adjustment from the control station.

d Parallel Operation In case of paralleloperation of generators, the governing system is topermit stable operation to be maintained over theentire operational speed range of the prime movers.

e Protection for Regenerated Power Brakingresistors or ballast consumers are to be provided toabsorb excess amounts of regenerated energy and toreduce the speed of rotation of the propulsion motor.These braking resistors or ballast consumers are to belocated external to the mechanical and electricrotating machines. Alternatively, the amount ofregenerated power may be limited by the action of thecontrol system.

4/5D2.17.5 Rotating Machines for PropulsionThe following requirements are applicable topropulsion generators and propulsion motors

a Ventilation and Protection Electric rotatingmachines for propulsion are to be enclosed ventilatedor be provided with substantial wire or mesh screen toprevent personnel injury or entrance of foreignmatter. Dampers are to be provided in ventilating airducts except when recirculating systems are used.


b Fire-extinguishing Systems Electric rotatingmachines for propulsion which are enclosed or inwhich the air gap is not directly exposed are to befitted with fire-extinguishing systems suitable for firesin electrical equipment. This will not be requiredwhere it can be established that the machineryinsulation is self-extinguishing.

c Air Coolers Air cooling systems for propulsiongenerators are to be in accordance with 4/4.11.3 and4/4.11.7.

d Temperature Sensors Stator windings of A.C.machines and interpole windings of D.C. machines,rated above 500 kW, are to be provided withtemperature sensors. See Table 4/11.9.

4/5D2.17.6 Propulsion GeneratorsExcitation current for propulsion generators may bederived from attached rotating exciters, staticexciters, excitation motor-generator sets, or specialpurpose generating units. Power for these excitersmay be derived from the machine being excited orfrom any craft service, emergency, or special purposegenerating units.

4/5D2.17.7 Direct-current (D.C.) PropulsionMotors

a Rotors The rotors of D.C. propulsion motorsare to be capable of withstanding overspeeding up tothe limit reached in accordance with thecharacteristics of the overspeed protection device atits normal operational setting.

b Overspeed Protection An overspeedprotection device is to be provided to preventexcessive overspeeding of the propulsion motors dueto light loads, loss of propeller, etc.

4/5D2.17.8 Electric Couplingsa General Couplings are to be enclosed

ventilated or be provided with wire or mesh screen toprevent personnel injury or the entrance of foreignmaterial. All windings are to be specially treated toresist moisture, oil and salt air.

b Accessibility for Repairs The coupling is to bedesigned to permit removal as a unit without movingthe engine. See also 4/5D2.15.2a.

c Temperature Rating The limits of temperaturerise are to be the same as for alternating-currentgenerators given in Tables 4/5C.2a and 4/5C.3,except that when a squirrel-cage element is used, thetemperature of this element may reach such values asare not injurious. Depending upon the coolingarrangements, the maximum temperature rise mayoccur at other than full-load rating so that heat runswill require special consideration; for this purpose,when an integral fan is fitted, the couplingtemperatures are not to exceed the limits in Tables4/5C.2a and 4/5C.3 when operated continuously at70% of full-load rpm, full excitation and rated torque.Temperature rises for insulation materials above 180

oC (356 oF) will be considered in accordance with4/5.13.6.

d Excitation Excitation is to be provided asrequired for propulsion generators. See 4/5C2.19.1,4/5C2.21.1d, and 4/5D2.17.6.

e Control Equipment Electric-coupling controlequipment is to be combined with the prime moverspeed and reversing control and is to include a two-pole disconnect switch, short-circuit protection only,ammeter for reading coupling current, dischargeresistor and interlocking to prevent energizing thecoupling when the prime mover control levers are inan inappropriate position.

f Nameplates Nameplates of corrosion-resistantmaterial are to be provided in an accessible positionof the electric coupling and are to indicate at least theinformation as listed in Table 4/5D.1a.

4/5D2.17.9 Semiconductor Converters forPropulsion

a General Converter enclosures and other partssubject to corrosion are to be made of corrosion-resistant material or of a material rendered corrosionresistant. Ambient air temperature is to be inaccordance with 4/5.13. In the case of water-cooledconverters, the inlet cooling water temperature is tobe considered at 30 oC (86 oF), unless otherwiseapproved. In all cases, the temperature rise under allconditions is to be limited to such a value as willpermit the converter to meet the specifiedperformance criteria. Schematic and one linediagrams are to be submitted for review.

b Testing and Inspection Semiconductorconverters for propulsion systems are to be tested inthe presence of and inspected by the Surveyor,preferably at the plant of the manufacturer. Duplicateunits of previously tested semiconductor convertersare to be tested only as deemed necessary by theSurveyor to demonstrate successful operation.

c Insulation Test The insulation ofsemiconductor converters is to be tested with all theparts completely assembled not withstanding previoustests carried out by the manufacturer on individualparts. The dielectric strength is to be tested by thecontinuous application for 60 seconds of analternating voltage having a crest value equal to thesq. root of [2] times the specified test voltage and afrequency of 20 to 60 Hz. The standard test voltage isto be twice the normal voltage of the circuit to whichit is applied plus 1000 volts except that where thesecondary circuit operates below 60 volts, the testvoltage is to be 600 volts r.m.s. and where in therange of 60 to 90 volts, the test voltage is to be 900volts r.m.s. The dielectric test voltage is to be appliedbetween each circuit and earthed metal parts.Alternative test procedures will be considered wherethe above requirement could result in damage tosensitive components.


d Design Data The following limiting repetitivepeak voltages are to be used as a base for thesemiconductor device:

- when connected to a supply specifically forpropeller drives: URM = 1.5 U

P;

- when connected to a common main supply:URM = 1.8 U

P (U

P is the peak value of the rated voltage at the

input of the semiconductor converter).

If the semiconductors are connected in series, theabove values may be increased by 10 %.

e Watertight Enclosures Converter units havinga watertight enclosure are to meet successfully theinsulation test specified in 4/5D2.17.9c after beingsubjected to a stream of water from a nozzle not lessthan 25 mm (1 in.) in diameter under a head of 10.5m (35 ft), played on the enclosure for at least 15minutes from a distance of 3 m (10 ft).

f Terminals The alternating current terminalsare to be marked with the letters A.C. The directcurrent terminals are to be marked with a plus (+) onthe positive terminal and a minus (-) on the negativeterminal.

g Nameplates Nameplates of corrosion-resistantmaterial are to be provided in an accessible positionof the semiconductor converter or its enclosure andare to indicate at least the information as listed inTable 4/5D.1b.

4/5D2.17.10 Reactors and Transformers forSemiconductor Converters

a General Interphase reactors and transformersused with semiconductor converters are to conformwith the requirements of 4/5C5.1.1, 4/5C5.1.2c,4/5C5.3, 4/5C5.5.1 and 4/5C5.5.2, and the following.

b Voltage Regulation Means to regulatetransformer output voltage are to be provided to takecare of increase in converter forward resistance and inaddition to obtain the necessary performancecharacteristics of the converter unit in which thetransformer is used.

c High Temperature Alarm Interphase reactorsand transformers used with the semiconductorconverters for main and auxiliary propulsion systemsare to be provided with high temperature alarm at theswitchboard or the propulsion control station. Thesetting value of the alarm is to be determined by theirspecific insulation class and is not to exceed thetemperature corresponding to the limit listed in Table4/5C.8.

4/5D2.17.11 Switchesa General Design All switches are to be

arranged for manual operation and so designed thatthey will not open under ordinary shock or vibration;contactors, however, may be operated pneumatically,

by solenoids, or other means in addition to themanual method which is to be provided unlessotherwise approved.

b Generator and Motor Switches Switches forgenerators and motors are preferably to be of the air-break type but for alternating-current systems, wherethey are to be designed to open full-load current atfull voltage, oil-break switches using nonflammableliquid may be used if provided with leak-proof,nonspilling tanks.

c Field Switches Where necessary, field switchesare to be arranged for discharge resistors unlessdischarge resistors are permanently connected acrossthe field. For alternating-current systems, means areto be provided for de-energizing the excitationcircuits by the unbalance relay and ground relay.

4/5D2.17.12 Propulsion Cablesa Conductors The conductors of cables external

to the components of the propulsion plant, other thancables and interconnecting wiring for computers, dataloggers or other automation equipment requiringcurrents of very small value, are to consist of not lessthan seven strands and have a cross-sectional area ofnot less than 1.5 mm2 (2,960 circ. mils).

b Insulation Materials Ethylene-propylenerubber, cross-linked polyethylene, or silicone rubberinsulated cables are to be used for propulsion powercables except that polyvinyl chloride insulated cablesmay be used where the normal ambient temperaturewill not exceed 50 oC (122 oF).

c Sheath, Jacket and Armor All cables are tohave suitable moisture-resistant jackets and braidedmetallic armor. Impervious metallic sheaths will beconsidered but are not to be used with single-conductor alternating-current cables.

d Inner Wiring The insulation of internal wiringin main control gear, including switchboard wiring,shall be of flame-retardant quality.

e Testing All propulsion cables, other thaninternal wiring in control gears and switchboards, areto be subjected to dielectric and insulation tests in thepresence of the Surveyor.

4/5D2.19 Dock and Sea Trials

Complete tests are to be carried out includingduration runs and maneuvering tests which shouldinclude a reversal of the craft from full speed ahead tofull speed astern, tests for operation of all protectivedevices and stability tests for control. All testsnecessary to demonstrate that each item of plant andthe system as a whole are satisfactory for duty are tobe performed. Immediately prior to trials, theinsulation resistance is to be measured and recorded.


4/5D3. Electrical Plants of Less Than 75 kW

4/5D3.1 GeneralElectrical plants having an aggregate capacity of lessthan 75 kW are to comply with the followingrequirements and the requirements in this Section 4/5,as applicable -- except 4/5.17, 4/5A1.3, 4/5A1.5,4/5A2, 4/5A3, 4/5A4.1.6b, 4/5A5.1.5, 4/5A6.5,4/5A6.7, 4/5A7.3, 4/5A8, 4/5A9.1, 4/5A9.3,4/5A10.3, 4/5B1.1, 4/5B2.9, 4/5C2.15.4,4/5C4.19.2d and .2e, 4/5C7 and 4/5D1.

4/5D3.3 Standard DetailsStandard wiring practices and details including suchitems as cable supports, earthing details, bulkheadand deck penetrations, cable joints and sealing, cablesplicing, watertight and explosion-proof connectionsto equipment, earthing and bonding connections, etc.,as applicable, are to be indicated on the submittedplans or may be submitted in a booklet format.

4/5D3.5 Calculations of Short-circuit CurrentsIn the absence of precise data, the following shortcircuit currents at the machine terminals are to beassumed:

1 Direct Current Systems Ten times the full loadcurrent for generators normally connected (includingspare) for each generator capable of beingsimultaneously connected.

Six times full load current for motorssimultaneously in service

2 Alternating Current Systems Ten times the fullload current for generators normally connected(including spare) for each generator capable of beingsimultaneously connected - symmetrical r.m.s.

Three times full load current of motorssimultaneously in service.

4/5D3.7 Lightning ProtectionFor lightning protection systems, see 4/5B2.1.4a.

4/5D3.9 Temperature RatingsIn the requirements contained in 4/5D3, an ambienttemperature of 40C (140F) has been assumed for alllocations. Where the ambient temperature is inexcess of this value, the total temperature specified isnot to be exceeded. Where equipment has been ratedon ambient temperature less than that contemplated,consideration will be given to the use of suchequipment provided the total temperature for whichthe equipment is rated will not be exceeded.

4/5D3.11 GeneratorsCraft using electricity for propulsion auxiliaries orpreservation of cargo are to be provided with at leasttwo generators. These generators are not to be drivenby the same engine. The capacity of the generating

sets is to be sufficient to carry the necessary loadessential for the propulsion and safety of the craft andpreservation of the cargo with any one generator setin reserve. Craft having only one generator are to beprovided with a battery source to supply sufficientlighting for safety.

4/5D3.13 Emergency Source of Power1 Capacity The emergency source of electrical

power is to have adequate capacity to provideemergency lighting for a period of at least 5 hours.

2 Sources The emergency power source may beany of the following:

a An automatically connected or manuallycontrolled storage battery; or

b An automatically or manually started generator,or

c Relay-controlled, battery-operated lanterns.3 Battery Sources Where the source of electrical

power is a battery connected to a charging devicewith an output of more than 2 kW, the battery is to belocated as near as practicable to but not in the samespace as the emergency switchboard, distributionboard or panel.4/5D3.15 Cable ConstructionCables are to have copper conductors constructed inaccordance with a recognized standard and are to beof the stranded type, except sizes not exceeding 1.5mm2 (16 AWG) may have solid conductors.

4/5D3.17 Switchboards, Distribution Boards andPanels

1 Installation Switchboards, distribution boxespanels and panels are to be installed in dry accessible,and well-ventilated areas. Not less than 610 mm (24in.) clearance is to be provided in front ofswitchboards, distribution boxes panels and panels.When located at the helm or other area adjacent to orpart of an open cockpit or weather deck, they are tobe protected by a watertight enclosure.

2 Instrumentation A voltmeter, ammeter,frequency meter, and voltage regulator are to beprovided for each generator installed. Controlequipment and measuring instruments are to beprovided as necessary to insure satisfactory operationof the generator or generators.

4/5D3.19 Navigating Running Lights

Mast head, port, starboard, and stern lights whenrequired are to be controlled by a running lightindicator panel. A fused-feeder disconnect switch isto be provided; the rating of the fuses is to be at leasttwice that of the largest branch fuse and greater thanthe maximum panel load.


Table 4/5D.1 Nameplates

a. Electric Coupling [See 4/5D2.17.8e]

The manufacturer's nameThe manufacturer's type and frame designationThe outputKind of ratingThe temperature rise at rated load and designambient temperatureThe speed (r.p.m.) at rated loadThe rated voltageThe exciter rated voltageThe Exciting current in amperes at rating

b. Semiconductor Converter [See 4/5D2.17.9g]

The manufacturer's name and addressThe manufacturer's serial numberThe type (silicon, copper oxide, etc.)The rated A.C. voltsThe rated A.C. amperesNumber of phasesFrequencyThe rated D.C. voltsThe rated D.C. amperesThe ambient temperature rangeThe cooling medium

PART 4 SECTION 5|71 Electrical Installations -- Part E. Specialized Vessels and Services

Part E. Specialized Craftand Services

4/5E1 Installations in Special-category Spaces

4/5E1.1 Application

In addition to the foregoing requirements in thisSection, the following requirements are applicable forinstallations in special-category spaces.

4/5E1.3 Ventilation System

4/5E1.3.1 ArrangementThe ventilating system for special-category spaces isto be independent from other ventilation systems andis to be capable of being controlled from a positionoutside the space.

4/5E1.3.2 CapacityAn effective power ventilation system of sufficientcapacity to give at least 10 air changes per hour whilenavigating and 20 air changes per hour at thequayside during vehicle loading and unloadingoperations is to be provided.

4/5E1.3.3 FansExhaust fans are to be of non-sparking construction inaccordance with 4/5B7.7.

4/5E1.3.4 Material and Arrangement of DuctsVentilation ducts including dampers are to be of steel.Ducts serving spaces capable of being sealed are tobe separated for such space.

4/5E1.3.5 Exhaust Inlet and OutletInlet for exhaust ducts are to be located within 450mm (17.75 in.) above the vehicle deck. The outlet isto be sited in a safe position, having regard to thesource of ignition near the outlet.

4/5E1.3.6 Emergency ShutdownArrangements are to be provided to permit a rapidshutdown and effective closure of ventilation systemin case of fire, taking into account the weather andsea conditions. See also 4/5E1.3.1.

4/5E1.3.7 Operating Compartment IndicationMeans are to be provided on the operatingcompartment or other appropriate locations toindicate any loss of the ventilating capacity.

4/5E1.5 Location and Type of Equipment

4/5E1.5.1 Certified Safe Type EquipmentExcept as provided for in 4/5E1.5.2 below, electricalequipment and wiring within the enclosed vehiclespaces referred to in 4/5E1.3.1 are to be increased-safety, explosion-proof, or intrinsically-safe type.

4/5E1.5.2 ArrangementsExcept for a distance within 450 mm (17.75 in.)above a platform that does not have openings ofsufficient size permitting penetration of petroleumgases downward, electrical equipment of a type soenclosed and protected as to prevent the escape ofsparks, e.g. protection degree of IP55 or equivalent.

4/5E1.5.3 Equipment in Ducts from Vehicle SpaceElectrical equipment and wiring installed within anexhaust duct are to be increased-safety, explosion-proof, or intrinsically-safe type.

PART 4 SECTION 6|1 Pumps and Piping Systems

PART 4 SECTION 6

Pumps and Piping Systems

4/6.1 Construction and Installation

4/6.1.1 General RequirementsAll craft are to be provided with the necessary pumpsand piping systems for safe and efficient operation inthe service for which they are intended. Materialsand workmanship are to be in accordance with goodmarine practice and to the satisfaction of theSurveyor. The arrangements and details are tocomply with the following requirements which areapplicable to all oceangoing craft but which may bemodified for craft classed for limited service.

4/6.1.2 Piping GroupsTo distinguish between detail requirements for thevarious systems the piping on shipboard is dividedinto two groups.

Group I in general includes all piping intended forworking pressures or temperatures in various servicesas follows:

Service Pressure Temperaturebar (kgf/cm2, psi) C (F)

Vapor and Gas over 10.3 (10.5, 150) over 343 (650)Water over 15.5 (15.8, 225) over 177 (350)Lubricating Oil over 15.5 (15.8, 225) over 204 (400)Fuel Oil over 10.3 (10.5, 150) over 66 (150)Hydraulic Fluid over 15.5 (15.8, 225) over 204 (400)

Group II includes all piping intended for workingpressures and temperatures below those stipulatedunder Group I. Group II also includes open-endedlines such as drains, overflows, engine exhausts andvents.

4/6.3 Plans and Data to Be Submitted

4/6.3.1 PlansBefore proceeding with the work, plans in accordancewith 4/1.11 are to be submitted, showing clearly thediagrammatic details or arrangement of theequipment.

4/6.3.2 All Piping SystemsThe plans are to consist of a diagrammatic drawing ofeach system accompanied by lists of material givingsize, wall thickness, maximum working pressure andmaterial of all pipes and the type, size, pressure ratingand material of valves and fittings.

4/6.3.3 Booklet of Standard DetailsA booklet of standard piping practices and detailsincluding such items as bulkhead, deck and shellpenetrations, welding details including dimensions,pipe joining details, etc. is to be submitted. Pipewelding details are to comply with Section 2/3.

4/6.4 Material Tests and Inspection

4/6.4.1 Specifications and Purchase OrdersThe appropriate material to be used for the variouspipes, valves and fittings is indicated in this section.The material is to be made in accordance with therequirements of Section 2/2, except that tests ofmaterial for valves, fittings, fluid power cylinders,and Group II piping need not be witnessed by theSurveyor. Where electric resistance welding is used,the requirements of Section 2/3 are also applicable.Copies in duplicate of the purchase orders formaterial requiring test and inspection at the mills orplace of manufacture are to be forwarded to theBureau for the information of the Surveyor.

4/6.4.2 Special MaterialsIf it is desired to use special alloys or other materialsnot covered by the Rules, the use of such materialswill be specially considered for approval.

4/6.5 Definitions

4/6.5.1 Piping/Piping SystemsThe terms piping and piping systems include the pipe,fittings, system joints, method of joining and anyinternal or external liners, coverings and coatingsrequired to comply with the performance criteria. Forexample, if the basic material needs a fire protectivecoating to comply with the fire endurancerequirements, then the piping are to be manufacturedand tested with both the basic material and coatingattached and details are to be submitted to the Bureaufor approval.

4/6.5.2 JointsThe term joint refers to the method of connectingpipes by adhesive bonding, brazing, welding, boltedflanging, threading, etc.


4/6.5.3 FittingsThe term fittings refers to bends, elbows, fabricatedbranch pieces, etc.

4/6.5.4 Positive Closing ValvesPositive closing valves are valves that are capable ofmaintaining a set position under all operatingconditions.

4/6.5.5 Recognized Standard of ConstructionRecognized standards of construction are publishedconstruction standards from organizations, such asbut not limited to the American Society ofMechanical Engineers (ASME), American Society ofTesting and Materials (ASTM), Department ofTransportation (DOT), Japanese Industrial Standard(JIS), German Design Standard (DIN), BritishStandard Code of Practice (BSI), which arerecognized by the Bureau as being acceptablestandards for a specific purpose or service. Eachstandard is to be used independently and in aconsistent manner.

4/6.5.6 Standard or Extra-Heavy PipePipe thickness referred to as Standard or Extra-Heavyare the equivalent of American National StandardsInstitute Schedule 40 and Schedule 80 pipe up to amaximum wall thickness of 9.5 mm (0.375 in.) and12.5 mm (0.5 in.), respectively.

4/6.7 General Installation Details

4/6.7.1 ProtectionPipes, valves and operating rods are to be effectivelysecured and adequately protected from mechanicaldamage. These protective arrangements are to befitted so that they may be removed to enableexamination of the pipes, valves, and operating rodsprotected.

4/6.7.2 Pipes Near SwitchboardsThe leading of pipes in the vicinity of switchboards isto be avoided as far as possible. When such leads arenecessary, care is to be taken to fit no flanges orjoints over or near the switchboards unless provisionis made to prevent any leakage from damaging theequipment.

4/6.7.3 Expansion or Contraction StressesProvision is to be made to take care of expansion orcontraction stresses in pipes due to temperaturechanges or working of the hull. Slip joints of anapproved type may be used in systems and locationswhere possible leakage will not be hazardous.

4/6.7.4 Non-Metallic Expansion JointsMolded expansion fittings of reinforced rubber orother suitable materials may be used in circulatingwater piping systems in machinery spaces. Suchfittings are to be oil resistant. The maximum workingpressure is not to be greater than 1/4 of thehydrostatic bursting pressure of the fitting asdetermined by a prototype test. Manufacturer's nameand the month and year of manufacture are to beembossed or otherwise permanently marked on theoutside edge of one of the flanges or other easilyexamined area of all flexible expansion jointsintended for use in sea water piping systems over 150mm (6 in.). Plans of the molded or built-up flexibleexpansion joints in sea water piping systems over 150mm (6 in.), including details of the internalreinforcement arrangements, are to be submitted forapproval.

4/6.7.5 Bulkhead, Deck or Tank TopPenetrations

Where pipes pass through bulkheads, decks or tanktops, the penetrations are to be made by methodswhich will maintain the watertight, fire-tight orsmoke-tight integrity of the bulkhead, deck or tanktop. Bolted connections are to have the boltsthreaded through the plating and welded connectionsare to be welded on both sides or with full-strengthwelds from one side.

4/6.7.6 Collision-Bulkhead PenetrationsPipes piercing the collision bulkhead are to be fittedwith suitable valves operable from above thebulkhead deck and secured to the bulkhead, generallyinside the forepeak. Cast iron is not to be used forthese valves. The use of nodular iron, also known asductile iron or spheroidal-graphite iron will beaccepted, provided the material has an elongation notless than 12% in 50 mm (2 in.). Tanks forward of thecollision bulkhead are not to be arranged for thecarriage of oil or other liquid substances that areflammable.

4/6.7.8 Sluice Valves and CocksNo valve or cock for sluicing purposes is to be fittedon a collision bulkhead. Sluice valves or cocks maybe fitted only on other watertight bulkheads, whenthey are at all times accessible for examination. Thecontrol rods are to be operable from the bulkheaddeck and are to be provided with an indicator to showwhether the valve or cock is open or closed. Thecontrol rods are also to be properly protected frominjury and their weight is not to be supported by thevalve or cock.


4/6.7.9 Relief ValvesAll systems which may be exposed to pressuresgreater than that for which they are designed are to besafeguarded by suitable relief valves or theequivalent, and pressure containers such asevaporators, heaters, etc., which may be isolated froma protective device in the line are to have suchdevices either directly on the shell or between theshell and the isolation valve.

a Exceptions In pumping systems such as oilpiping and fire main, where ordinarily relief valvesare required at the pump, such valves need not befitted when the system is served only by centrifugalpumps so designed that the pressure delivered cannotexceed that for which the piping is designed.

4/6.7.10 Instrumentsa Temperature Thermometers and other

temperature sensing devices registering throughpressure boundaries are to be provided withinstrument wells to allow for instrument removalwithout impairing the integrity of the pressurizedsystem.

b Pressure Pressure sensing devices are to beprovided with valve arrangements to allow forinstrument isolation and removal without impairingthe pressurized systems' integrity.

4/6.7.11 Hosea Hoses in Vital Systems Hose assemblies may

be installed between two points where flexibility isrequired but are not to be subject to torsionaldeflection (twisting) under normal operatingconditions. In general, hose is to be limited to thelength necessary to provide for flexibility and forproper operation of machinery. Each hose is to bevisible at all times, easily accessible, and confined toone watertight compartment. Burst pressure of thehose is not to be less than four times the relief valvesetting.

Where the use of non-metallic hose is permitted,the hose materials are to be suitable for the intendedservice. Hoses for oil service are to be fire resistantand reinforced with wire braid or other suitablematerial.

b Hoses in Non-vital Systems Flexible metallicand non-metallic hose may be installed throughout insystems such as sanitary drains, potable water, andfresh water cooling for non-vital equipment. Wherehose passes through watertight bulkheads, it is to beconnected to a rigid sleeve of the same material as thebulkhead and the sleeve is to be fitted with either areadily accessible valve at each side of the bulkheador a single valve on one side of the bulkhead with aremote operator capable of operation from above thebulkhead deck.

c Fire-resistant Hoses In order for a non-metallic flexible hose to be considered fire-resistant, aprototype of the hose is to be subjected to a fire testfor at least 30 minutes at a temperature of not lessthan 800C (1472F) while water at the maximumservice pressure is circulated inside. The temperatureof the water at the outlets is not to be less than 80C(176F) during the test. The tested hose is to becomplete with end fittings and no leakage is to berecorded during or after the test. As an alternative,the fire test may be conducted with the circulatingwater at a pressure of at least 5 bar (5.1 kgf/cm2, 72.5psi) and a subsequent pressure test to twice the designpressure.

d Hose Fittings Each hose is to be completewith factory assembled end fittings or factorysupplied end fittings installed in accordance withmanufacturer's procedures. The use of non-metallichoses which are not provided with factory assembledend fittings will be considered for non-combustibleand non-toxic, Group II piping systems under 5.2 bar(5.3 kgf/cm2, 75 psi) in pipe sizes up to 114.3 mmO.D. (4 in. NPS). Such hoses are to be located inaccessible locations and secured by means of at leasttwo stainless-steel hose clamps at each end. Suchclamps are to be at least 12 mm (0.5 in.) wide and arenot to be dependent on spring tension to remainfastened.

4/6.7.12 Control of Static ElectricityPiping systems that are routed through hazardousareas are to be suitably grounded either by welding orbolting the pipes or their supports directly to the hullof the ship or through the use of bonding straps. Ingeneral, the resistance between ground points alongthe length, across joints, and from pipe to ground isnot to exceed 1 megohm. Where bonding straps areused, they are to be clearly visible, protected frommechanical damage and of a type not affected bycorrosive product and paint. Bonding straps arerequired for piping systems which are notpermanently connected to the hull, including pipingsystems which are electrically separated from the hulland pipe connections arranged for removal of spoolpieces.

4/6.7.13 Leakage ContainmentFor areas where leakage may be expected such as oilburners, purifiers, oil drains, valves under day tanks,etc., means of containing the leakage are to beprovided. Where drain pipes are fitted for collectedleakage, they are to be led to a suitable oil drain tanknot forming part of an overflow system.


4/6.7.14 Piping on Aluminum CraftOn a craft with an aluminum hull, the use of steel,copper or other non-aluminum pipes, valves andfittings will require special attention to avoid galvaniccorrosion with dissimilar metals. Piping runs ofmaterial not compatible with aluminum are to beisolated from the hull by suitable isolating brackets orinsulating material. Where non-aluminum pipes passthrough decks, bulkheads, tank tops, and shell plating,they are to be isolated from the vessel’s structure withsuitable insulation.

4/6.8 Pumps

4/6.8.1 GeneralFor self-propelled craft 500 gross tons and above, thefollowing pumps are to meet the test requirements of4/6.8.3 and 4/6.8.5:

Fire pumpBilge pumpBallast pumpHydraulic pumps for steering gear, anchor

windlass and variable pitch propellers

The tests are to be carried out at the manufacturer'splant in the presence of the Surveyor. The capacitytest will not be required nor will the hydrostatic testneed to be witnessed by the Surveyor for individualpumps assembled on a production line basis,provided the Surveyor is satisfied from periodicinspections and the manufacturer's quality assuranceprocedures that the pump capacities are acceptableand that hydrostatic testing is being performed. See4/1.2. For pumps associated with reciprocatinginternal combustion engines and reduction gears, see4/4.21

4/6.8.3 Hydrostatic TestAll pumps are to be hydrostatically tested to 1.5P, butnot less than 3.9 bar (4 kgf/cm2, 57 psi), where P isthe maximum working pressure of the part concerned.When the suction and discharge sides of the pump aretested independently, the pump suction is to be testedto 1.5 times Ps, but not less than 3.9 bar (4 kgf/cm2,57 psi), where Ps is the maximum pressure availablefrom the system at the suction inlet. For steering gearpumps, also see 4/8.5

4/6.8.5 Capacity TestPump capacities are to be checked with the pumpoperating at design conditions (rated speed andpressure head). For centrifugal pumps, the pumpcharacteristic (head capacity) design curve is to beverified to the satisfaction of the Surveyor.

4/6.9 Pressure Tests

4/6.9.1 GeneralIn addition to the testing and inspection of materials,as required in Section 2/2, the following tests on thefabricated piping are to be witnessed by the Surveyorafter bending and the attachment of flanges:

4/6.9.2 Fuel Oil Service SystemPressure lines are to be tested after installation to 1.5times the design pressure of the system but not lessthan 3.4 bar (3.5 kgf/cm2, 50 psi).

4/6.9.3 Fuel Oil Suction and Transfer LinesFuel transfer systems are to be tested after installationto 3.4 bar (3.5 kgf/cm2, 50 psi). Fuel-oil gravity fedsuction lines are to be leak tested such that the testingprocedures reflect the static pressure workingconditions of the suction piping.

4/6.9.4 Starting Air PipingPiping in starting-air systems is to be tested,preferably before installation, to 1.5 times the designpressure of the system.

4/6.9.6 Hydraulic Power PipingAfter fabrication, the hydraulic power piping systemor each piping component is to be tested to 1.5 timesthe design pressure. For steering gear piping tests,see 4/8.8 and for controllable pitch propeller systempiping tests see 4/7.32.1c.1

4/6.9.7 Fixed Oxygen-Acetylene PipingThe piping system is to be tested in the presence ofthe Surveyor to 1.5 times the maximum designpressure and thoroughly purged with air before beingplaced in service. The medium used for pressuretesting of oxygen lines is to be oil-free andnonflammable. Material used externally for leaktesting oxygen lines is to be oil-free and, ifcombustible, is to be applied as a diluted watersolution.

4/6.9.8 All PipingAfter installation all piping is to be tested underworking conditions.

4/6.13 Metallic Pipes

4/6.13.1 Test and Inspection Group I PipingPipes intended for use in Group I piping systems areto be tested in the presence of and inspected by theSurveyor in accordance with Section 2/2 or suchother appropriate material specification as may beapproved in connection with a particular design. See4/6.67.3 for pipe used in hydraulic systems.


4/6.13.2 Steel Pipea Seamless Pipe Seamless-drawn steel pipe may

be used for all purposes.b Welded Pipe Electric resistance welded steel

pipe may be used for temperatures up to 343C(650F). Consideration will be given to the use ofelectric-resistance-welded (ERW) pipe for use above343C (650F) where the material is shown to besuitable for the intended service (i.e. in a non-corrosive environment, where design temperature isbelow the lowest graphitization temperature specifiedfor the material, etc.). Furnace butt-welded pipe up toand including 115 mm O.D. (4 in. NPS) may beused for Group II piping for temperatures up to 232C(450F) but is not to be used for flammable orcombustible fluids.

4/6.13.3 Copper PipeSeamless-drawn and welded copper pipe, unlessotherwise prohibited, may be used for all purposeswhere the temperature does not exceed 208C (406F)and within the limitations specified in the materialspecification.

4/6.13.4 Brass PipeSeamless-drawn brass pipe, unless otherwiseprohibited, may be used where the temperature doesnot exceed 208C (406F). In saltwater systems, onlyalloys with a zinc content of 15% or less whichcontain dezincification inhibitors such as tin,antimony or arsenic are to be used.

4/6.13.5 Aluminum PipeAluminum pipe is not to be used for fuel oil,lubricating oil, hydraulic oil or other flammable orcombustible liquids. Aluminum pipe is also not to beused for bilge piping within the machinery space orfor fire fighting systems.

Aluminum pipe may be used for all other serviceson craft constructed of aluminum or fiber-reinforcedplastic, including vents and sounding pipes from oiltanks.

4/6.13.6 Maximum Allowable Working Pressureand Minimum Thickness

The maximum allowable working pressure and theminimum thickness of pipes are to be determined bythe following equations, with due consideration beinggiven to the reduction in thickness at the outer radiusof bent pipes:

( )( )W

KS t c

D M t c=

−− −

tWD

KS MWC=

++

K = 20 (200, 2)W = maximum allowable working pressure in

bar, kgf/cm2 or psi. See Note 1.

t = minimum thickness of pipe in mm or inSee Note 5.

D = actual external diameter of pipe in mm orin.

S = maximum allowable fiber stress inN/mm2, kgf/mm2 or psi from Table 4/6.1.See Note 2.

M = factor from Table 4/6.1C = allowance for threading, grooving or

mechanical strength= 1.65 mm (0.065 in.) for plain-end steel

or wrought-iron pipe or tubing up to 115mm O.D. (4 in. NPS). See Note 3.

= 0.00 mm (0.000 in.) for plain-end steelor wrought-iron pipe or tubing up to 115mm O.D. (4 in. NPS) used for hydraulicpiping systems. See Note 3.

= 0.00 mm (0.000 in.) for plain-end steelor wrought- iron pipe or tubing 115 mmO.D. (4 in. NPS) and larger. See Note3.

= 1.27 mm (0.05 in.) for all threaded pipe17 mm O.D. ( 3/8 in.) and smaller

= depth of thread h for all threaded pipeover 17 mm O.D. ( 3/8 in.). See Note 4.

= depth of groove for grooved pipe= 0.00 mm (0.000 in.) for plain-end

nonferrous pipe or tubing. See Note 3.

Notes:1 The value of W used in the equations is to be not

less than 8.6 bar (8.8 kgf/cm2, 125 psi), except thatfor suction and other low-pressure piping ofnonferrous material, the actual working pressuremay be applied if a suitable addendum is providedagainst erosion and outside damage. However, inno case is the value of W to be less than 3.4 bar(3.5 kgf/cm2, 50 psi) for use in the equations.

2 Values of S for other materials are not to exceedthe stress permitted by ASME B31.1 Code forPressure Piping, Power Piping .

3 Plain-end pipe or tubing includes those joined byany method in which the wall thickness is notreduced.

4 The depth of thread h may be determined by theequation h = 0.8/n where n is the number ofthreads per inch, or in metric units by the equationh = 0.8n where n is the number of mm per thread.

5 If pipe is ordered by its nominal wall thickness, themanufacturing tolerance on wall thickness is to betaken into account.

4/6.13.7 Working Pressure and Thickness--Alternative Consideration

Consideration will be given to the maximum workingpressure and the minimum thickness of pipingdetermined from criteria of applicable recognizedstandards.


4/6.15 Plastic Pipes

4/6.15.1 GeneralPipes and piping components made of thermoplasticor thermosetting plastic materials, with or withoutreinforcement, may be used in piping systemsreferred to in Table 4/6.4 subject to compliance withthe following requirements. For the purpose of theserequirements “plastic” means both thermoplastic andthermosetting plastic materials, with or withoutreinforcement, such as polyvinyl chloride (PVC) andfiber reinforced plastics (FRP).

4/6.15.2 SpecificationRigid plastic pipes are to be in accordance with arecognized national or international standardacceptable to the Bureau. Specification for the plasticpipe, including thermal and mechanical propertiesand chemical resistance, is to be submitted for reviewtogether with the spacing of the pipe supports.

4/6.15.3 Designa Internal Pressure A pipe is to be designed for

an internal pressure not less than the design pressureof the system in which it will be used. The maximuminternal pressure, Pint, for a pipe is to be the lesser ofthe following:

PPsth

int =4

or PPlth

int .=

2 5

Psth = short-term hydrostatic test failure pressurePlth = long-term hydrostatic test failure pressure (

> 100,000 hours)

The hydrostatic tests are to be carried out under thefollowing standard conditions:

atmospheric pressure = 1 bar (1 kgf/cm2, 14.5 psi)relative humidity = 30%

fluid temperature = 25C (77F)

The hydrostatic test failure pressure may beverified experimentally or determined by acombination of testing and calculation methods,which are to be submitted to the Bureau for approval.

b External Pressure External pressure is to beconsidered for any installation which may be subjectto vacuum conditions inside the pipe or a head ofliquid on the outside of the pipe. A pipe is to bedesigned for an external pressure not less than thesum of the pressure imposed by the maximumpotential head of liquid outside the pipe plus fullvacuum, 1 bar (1 kgf/cm2, 14.5 psi), inside the pipe.The maximum external pressure for a pipe is to bedetermined by dividing the collapse test pressure by asafety factor of 3.

The collapse test pressure may be verifiedexperimentally or determined by a combination of

testing and calculation methods, which are to besubmitted to the Bureau for approval.

c Axial Strength1 The sum of the longitudinal stresses due

to pressure, weight and other dynamicand sustained loads is not to exceed theallowable stress in the longitudinaldirection. Forces due to thermalexpansion, contraction and externalloads, where applicable, are to beconsidered when determininglongitudinal stresses in the system.

2 In the case of fiber reinforced plasticpipes, the sum of the longitudinalstresses is not to exceed one-half of thenominal circumferential stress derivedfrom the maximum internal pressuredetermined according to 4/6.15.3a,unless the allowable longitudinal stressis verified experimentally or by acombination of testing and calculationmethods.

d Temperature The maximum allowableworking temperature of a pipe is to be in accordancewith the manufacturer’s recommendations, but ineach case it is to be at least 20C (36F) lower than theminimum heat distortion temperature of the pipematerial determined according to ISO 75 method A orequivalent. The minimum heat distortion temperatureis not to be less than 80C (176F).

Where low temperature services are considered,special attention is to be given with respect tomaterial properties.

e Impact Resistance Plastic pipes and joints areto have a minimum resistance to impact in accordancewith a recognized national or international standardsuch as ASTM D2444 or equivalent. After the impactresistance is tested, the specimen is to be subjected tohydrostatic pressure equal to the 2.5 times the designpressure for at least one hour.

f Fire Endurance Table 4/6.4 specifies fireendurance requirements for pipes based upon systemand location. Pipes and their associated fittingswhose functions or integrity are essential to the safetyof the craft are to meet the indicated fire endurancerequirements which are described below.

− Level 1 will ensure the integrity of thesystem during a full scale hydrocarbon fireand is particularly applicable to systemswhere loss of integrity may cause outflow offlammable liquids and worsen the firesituation. Piping having passed the fireendurance test specified in 4/6.15.7 for aduration of a minimum of one hour withoutloss of integrity in the dry condition isconsidered to meet Level 1 fire endurancestandard (L1).


− Level 2 intends to ensure the availability ofsystems essential to the safe operation of theship, after a fire of short duration, allowingthe system to be restored after the fire hasbeen extinguished. Piping having passed thefire endurance test specified in 4/6.15.7 for aduration of a minimum of 30 minuteswithout loss of integrity in the dry conditionis considered to meet Level 2 fire endurancestandard (L2).

− Level 3 is considered to provide the fireendurance necessary for a water filled pipingsystem to survive a local fire of shortduration. The system’s functions arecapable of being restored after the fire hasbeen extinguished. Piping having passed thefire endurance test specified in 4/6.15.8 for aduration of a minimum of 30 minuteswithout loss of integrity in the wet conditionis considered to meet Level 3 fire endurancestandard (L3).

Where a fire protective coating of pipes and fittings isnecessary for achieving the fire endurance standardsrequired, the following requirements apply.

1 Pipes are generally to be delivered fromthe manufacturer with the protectivecoating applied, with on-site applicationlimited to that necessary for installationpurposes (i.e., joints). See 4/6.15.4gregarding the application of the fireprotection coating on joints.

2 The fire protection properties of thecoating are not to be diminished whenexposed to salt water, oil or bilge slops.It is to be demonstrated that the coatingis resistant to products likely to come incontact with the piping.

3 In considering fire protection coatings,such characteristics as thermalexpansion, resistance against vibrationsand elasticity are to be taken intoaccount.

4 The fire protection coatings are to havesufficient resistance to impact to retaintheir integrity.

g Flame Spread All pipes, except those fittedon open decks and within tanks, cofferdams, voidspaces, pipe tunnels and ducts are to have low flamespread characteristics. The test procedures in IMOResolution A.653(16), modified for pipes as indicatedin 4/6.15.9, are to be used for determining the flamespread characteristics. Piping materials givingaverage values for all of the surface flammabilitycriteria not exceeding the values listed in ResolutionA.653(16) (surface flammability criteria of bulkhead,wall and ceiling linings) are considered to meet therequirements for low flame spread.

Alternatively, flame spread testing in accordancewith ASTM D635 may be used in lieu of the IMOflame spread test provided such test is acceptable tothe Administration.

h Electrical Conductivity1 Piping conveying fluids with a

conductivity less than 1000 picosiemens per meter are to be electricallyconductive.

2 Regardless of the fluid being conveyed,plastic pipes are to be electricallyconductive if the piping passes througha hazardous area.

3 Where electrically conductive pipe isrequired, the resistance per unit lengthof the pipes and fittings is not to exceed1 × 105 Ohm/m (3 × 104 Ohm/ft). Seealso 4/6.15.4d.

4 If the pipes and fittings are nothomogeneously conductive, theconductive layers are to be protectedagainst the possibility of spark damageto the pipe wall..

i Marking Plastic pipes and other componentsare to be permanently marked with identification inaccordance with a recognized standard. Identificationis to include pressure ratings, the design standard thatthe pipe or fitting is manufactured in accordance with,and the material with which the pipe or fitting ismade.

4/6.15.4 Installation of Plastic Pipesa Supports

1 Selection and spacing of pipe supportsin shipboard systems are to bedetermined as a function of allowablestresses and maximum deflectioncriteria. Support spacing is not to begreater than the pipe manufacturer’srecommended spacing. The selectionand spacing of pipe supports are to takeinto account pipe dimensions,mechanical and physical properties ofthe pipe material, mass of pipe andcontained fluid, external pressure,operating temperature, thermalexpansion effects, loads due to externalforces, thrust forces, water hammer andvibrations to which the system may besubjected. Combination of these loadsis to be checked.

2 Each support is to evenly distribute theload of the pipe and its contents over thefull width of the support. Measures areto be taken to minimize wear of thepipes where they contact the supports.


3 Heavy components in the piping systemsuch as valves and expansion joints areto be independently supported.

4 The supports are to allow for relativemovement between the pipes and theship’s structure, having due regard tothe difference in the coefficients ofthermal expansion and deformations ofthe ship’s hull and its structure.

5 When calculating the thermalexpansion, the system workingtemperature and the temperature atwhich assembling is performed are to betaken into account.

b External Loads When installing the piping,allowance is to be made for temporary point loads,where applicable. Such allowances are to include atleast the force exerted by a load (person) of 980 N(100 kgf, 220 lbf) at mid-span on any pipe more than100 mm ( 4 in.) nominal diameter.

Pipes are to be protected from mechanical damagewhere necessary.

c Plastic Pipe Connections1 The strength of fittings and joints is not

to be less than that of the piping theyconnect.

2 Pipes may be joined using adhesive-bonded, welded, flanged or other joints.

3 Tightening of flanged or mechanicallycoupled joints is to be performed inaccordance with manufacturer’sinstructions.

4 Adhesives, when used for jointassembly, are to be suitable forproviding a permanent seal between thepipes and fittings throughout thetemperature and pressure range of theintended application.

Joining techniques are to be in accordance withmanufacturer’s installation guidelines. Personnelperforming these tasks are to be qualified to thesatisfaction of the Bureau, and each bondingprocedure is to be qualified before shipboard pipinginstallation commences. Requirements for jointbonding procedures are in 4/6.15.6.

d Electrical Conductivity Where electricallyconductive pipe is required by 4/6.15.3h, installationof the pipe is to be in accordance with the following:

1 The resistance to earth (ground) fromany point in the system is not to exceed1 megohm. The resistance is to bechecked in the presence of the Surveyor.

2 Where used, earthing wires or bondingstraps are to be accessible forinspection. The Surveyor is to verifythat they are in visible locations.

e Shell Connections Where plastic pipes arepermitted in systems connected to the shell of the

craft, the valves and the pipe connection to the shellare to be metallic. The side shell valves are to bearranged for remote control from outside the space inwhich the valves are located. For further details ofthe shell valve installation, their connections andmaterial, refer to 4/6.25.

f Bulkhead and Deck Penetrations1 The integrity of watertight bulkheads

and decks is to be maintained whereplastic pipes pass through them.

2 Where plastic pipes pass through fire-resisting divisions, arrangements are tobe made to ensure that the fireendurance is not impaired. Thesearrangements are to be tested inaccordance with IMO Resolution. A754 (18), Recommendation on FireResistance Tests for “A”, “B” and “F”Class Divisions, as amended.

3 If the bulkhead or deck is a fire divisionand destruction by fire of plastic pipesmay cause inflow of liquid from tank, ametallic shut-off valve operable fromabove the bulkhead deck is to be fittedat the bulkhead or deck.

g Application of Fire Protection Coatings Fireprotection coatings are to be applied on the joints,where necessary for meeting the required fireendurance criteria in 4/6.15.3f, after performinghydrostatic pressure tests of the piping system (see4/6.15.10). The fire protection coatings are to beapplied in accordance with the manufacturer’srecommendations, using a procedure approved ineach particular case.

4/6.15.5 Manufacturing of Plastic PipesPreferably, the manufacturer is to have a qualitysystem and be certified in accordance with 4/1.2 orISO 9001. The quality system is to consist ofelements necessary to ensure that pipes andcomponents are produce with consistent and uniformmechanical and physical properties in accordancewith recognized standards and is to include thefollowing tests.

− Samples of pipe are to be tested to determinethe short-term and long-term hydrostaticdesign strength. These samples are to beselected randomly from the productionfacilities.

− For piping required to be electricallyconductive, representative samples of pipeare to be tested to determine electricalresistance per unit length.

− Random samples of pipe are to be tested todetermine the adhesion qualities of thecoating to the pipe.


Where the manufacturer does not have a certifiedquality system, the tests listed above will be requiredusing samples from each batch of pipes beingsupplied for use aboard the craft.

Regardless of whether the manufacturer has acertified quality system, each length of pipe is to betested at the manufacturer’s production facility to ahydrostatic pressure not less than 1.5 times themaximum allowable internal pressure of the pipe in4/6.15.3a.

4/6.15.6 Plastic Pipe Bonding ProcedureQualification

a Procedure Qualification Requirements1 To qualify joint bonding procedures, the

tests and examinations specified hereinare to be successfully completed. Theprocedure for making bonds is toinclude the following:− materials used− tools and fixtures− environmental requirements− joint preparation requirements− cure temperature− dimensional requirements and

tolerances− test acceptance criteria for the

completed assembly2 Any change in the bonding procedure

which will affect the physical andmechanical properties of the joint willrequire the procedure to be requalified.

b Procedure Qualification Testing1 A test assembly is to be fabricated in

accordance with the procedure to bequalified and it is to consist of at leastone pipe-to-pipe joint and one pipe-to-fitting joint. When the test assemblyhas been cured, it is to be subjected to ahydrostatic test pressure at a safetyfactor of 2.5 times the design pressureof the test assembly, for not less thanone hour. No leakage or separation ofjoints is to be allowed. The test is to beconducted so that the joint is loaded inboth longitudinal and circumferentialdirection.

2 Selection of the pipes used for testassembly is to be in accordance with thefollowing:

− When the largest size to be joined is200 mm (8 in.) nominal outsidediameter or smaller, the test assembly isto be the largest pipe size to be joined.

− When the largest size to be joined isgreater than 200 mm (8 in.) nominaloutside diameter, the size of the test

assembly is to be either 200 mm (8 in.)or 25% of the largest piping size to bejoined, whichever is greater.

3 When conducting performancequalifications, each bonder and eachbonding operator are to make up testassemblies, the size and number ofwhich are to be as required above.

4/6.15.7 Tests by the Manufacturer - FireEndurance Testing of Plastic Piping in theDry Condition (For Level 1 and 2)

a Test Method1 The specimen is to be subjected to a

furnace test with fast temperatureincrease similar to that likely to occur ina fully developed liquid hydrocarbonfire. The time/temperature is to be asfollows:

at the end of 5 minutes 945C (1733F)at the end of 10

minutes1033C (1891F)

at the end of 15minutes

1071C (1960F)


1098C (2008F)


1100C (2012F)

2 The accuracy of the furnace control is tobe as follows:

− During the first 10 minutes of the test,variation in the area under the curve ofmean furnace temperature is to bewithin ±15% of the area under thestandard curve.

− During the first 30 minutes of the test,variation in the area under the curve ofmean furnace temperature is to bewithin ±10% of the area under thestandard curve.

− For any period after the first 30 minutesof the test, variation in the area underthe curve of mean furnace temperatureis to be within ±5% of the area underthe standard curve.

− At any time after the first 10 minutes ofthe test, the difference in the meanfurnace temperature from the standardcurve is to be within ±100C (±180F).

3 The locations where the temperaturesare measured, the number oftemperature measurements and themeasurement techniques are to beapproved by the Bureau.

b Test Specimen1 The test specimen is to be prepared with

the joints and fittings intended for use inthe proposed application.


2 The number of specimens is to besufficient to test typical joints andfittings including joints between non-metal and metal pipes and metal fittingsto be used.

3 The ends of the specimen are to beclosed. One of the ends is to allowpressurized nitrogen to be connected.The pipe ends and closures may beoutside the furnace.

4 The general orientation of the specimenis to be horizontal and it is to besupported by one fixed support with theremaining supports allowing freemovement. The free length betweensupports is not to be less than 8 timesthe pipe diameter.

5 Most materials will require a thermalinsulation to pass this test. The testprocedure is to include the insulationand its covering.

6 If the insulation contains, or is liable toabsorb, moisture the specimen is not tobe tested until the insulation has reachedan air dry-condition, defined asequilibrium with an ambient atmosphereof 50% relative humidity at 20±5C(68±9F). Accelerated conditioning ispermissible provided the method doesnot alter the properties of thecomponent material. Special samplesare to be used for moisture contentdetermination and conditioned with thetest specimen. These samples are to beso constructed as to represent the loss ofwater vapor from the specimen havingsimilar thickness and exposed faces.

c Test Condition A nitrogen pressure inside thetest specimen is to be maintained automatically at 0.7± 0.1 bar (0.7 ± 0.1 kgf/cm2, 10 ± 1.5 psi) during thetest. Means are to be provided to record the pressureinside the pipe and the nitrogen flow into and out ofthe specimen in order to indicate leakage.

d Acceptance Criteria1 During the test, no nitrogen leakage

from the sample is to occur.2 After termination of the furnace test, the

test specimen together with fireprotective coating, if any, is to beallowed to cool in still air to ambienttemperature and then tested to themaximum allowable pressure of thepipes as defined in 4/6.15.3a and b .The pressure is to be held for aminimum of 15 minutes withoutleakage. Where practicable, thehydrostatic test is to be conducted onbare pipe (i.e., coverings and insulation

removed) so that any leakage will beapparent.

3 Alternative test methods and/or testprocedures considered to be at leastequivalent including open pit testingmethod, may be accepted in cases wherethe pipes are too large for the testfurnace.

4/6.15.8 Test by Manufacturer - Fire EnduranceTesting of Water-Filled Plastic Piping(For Level 3)

a Test Method1 A propane multiple burner test with a

fast temperature increase is to be used.2 For piping up to and including 152 mm

( 6 in.) O. D., the fire source is toconsist of two rows of 5 burners asshown in Figure 4/6.1. A constant heatflux averaging 113.6 kW/m2 ( 36,000BTU/hr-ft2) ± 10% is to be maintained12.5 ± 1 cm (5 ± 0.4 in.) above thecenterline of the burner array. This fluxcorresponds to a pre-mix flame ofpropane with a fuel flow rate of 5 kg/hr(11 lb/hr) for a total heat release of 65kW (3700 BTU/min.). The gasconsumption is to be measured with anaccuracy of at least ± 3% in order tomaintain a constant heat flux. Propanewith a minimum purity of 95% is to beused.

3 For piping greater than 152 mm (6 in.)O. D., one additional row of burners isto be included for each 51 mm (2 in.)increase in pipe diameter. A constantheat flux averaging 113.6 kW/m2

(36,000 BTU/hr-ft2) ± 10% is still to bemaintained at the 12.5 ± 1 cm (5 ± 0.4in.) height above the centerline of theburner array. The fuel flow is to beincreased as required to maintain thedesignated heat flux.

4 The burners are to be type “Sievert No.2942” or equivalent which produces anair mixed flame. The inner diameter ofthe burner heads is to be 29 mm (1.14in.). See Figure 4/6.1. The burnerheads are to be mounted in the sameplane and supplied with gas from amanifold. If necessary, each burner isto be equipped with a valve in order toadjust the flame height.

5 The height of the burner stand is also tobe adjustable. It is to be mountedcentrally below the test pipe with therows of burners parallel to the pipe’s


axis. The distance between the burnerheads and the pipe is to be maintained at12.5 ± 1 cm (5 ± 0.4 in.) during the test.The free length of the pipe between itssupports is to be 0.8 ±0.05 m (31.5 ± 2in.). See Figure 4/6.2.

b Test Specimen1 Each pipe is to have a length of

approximately 1.5 m (5 ft).2 The test pipe is to be prepared with

permanent joints and fittings intended tobe used. Only valves and straight jointsversus elbows and bends are to be testedas the adhesive in the joint is theprimary point of failure.

3 The number of pipe specimens is to besufficient to test all typical joints andfittings.

4 The ends of each pipe specimen are tobe closed. One of the ends is to allowpressurized water to be connected.

5 If the insulation contains, or is liable toabsorb, moisture the specimen is not tobe tested until the insulation has reachedan air dry-condition, defined asequilibrium with an ambient atmosphereof 50% relative humidity at 20±5C(68±9F). Accelerated conditioning ispermissible provided the method doesnot alter the properties of thecomponent material. Special samplesare to be used for moisture contentdetermination and conditioned with thetest specimen. These samples are to beso constructed as to represent the loss ofwater vapor from the specimen havingsimilar thickness and exposed faces.

6 The pipe samples are to rest freely in ahorizontal position on two V-shapedsupports. The friction between pipe andsupports is to be minimized. Thesupports may consist of two stands, asshown in Figure 4/6.2.

7 A relief valve is to be connected to oneof the end closures of each specimen

c Test Conditions1 The test is to be carried out in a

sheltered test site in order to prevent anydraft influencing the test.

2 Each pipe specimen is to be completelyfilled with dearated water to exclude airbubbles.

3 The water temperature is not to be lessthan 15C (59F) at the start and is to bemeasured continuously during the test.The water is to be stagnant and thepressure maintained at 3 ± 0.5 bar (3.1

± 0.5 kgf/cm2, 43.5 ± 7.25) during thetest.

d Acceptance Criteria1 During the test, no leakage from the

sample(s) is to occur except that slightweeping through the pipe wall may beaccepted.

2 After termination of the burner test, thetest specimen together with fireprotective coating, if any, is to beallowed to cool to ambient temperatureand then tested to the maximumallowable pressure of the pipes asdefined in 4/6.15.3a and b . Thepressure is to be held for a minimum of15 minutes without significant leakage(i.e., not exceeding 0.2 l/min. (0.05gpm)). Where practicable, thehydrostatic test is to be conducted onbare pipe (i.e., coverings and insulationremoved) so that any leakage will beapparent.

4/6.15.9 Tests by Manufacturer - Flame Spreada Test Method Flame spread of plastic piping is

to be determined by IMO Resolution A.653(16)entitled “Recommendation on Improved Fire TestProcedures for Surface Flammability of Bulkhead,Ceiling, and Deck Finish Materials” with thefollowing modifications.

1 Test are to be made for each pipematerial and size.

2 The test sample is to be fabricated bycutting pipes lengthwise into individualsections and then assembling thesections into a test sample asrepresentative as possible of a flatsurface. A test sample is to consist of atleast two sections. The test sample is tobe at least 800 ± 5 mm (31.5 ± 0.2 in.)long. All cuts are to be made normal tothe pipe wall.

3 The number of sections that must beassembled together to form a testsample is to be that which correspondsto the nearest integral number ofsections which makes up a test samplewith an equivalent linearlized surfacewidth between 155 mm (6 in.) and 180mm (7 in.). The surface width isdefined as the measured sum of theouter circumference of the assembledpipe sections that are exposed to theflux from the radiant panel.

4 The assembled test sample is to have nogaps between individual sections.


5 The assembled test sample is to beconstructed in such a way that the edgesof two adjacent sections coincide withthe centerline of the test holder.

6 The individual test sections are to beattached to the backing calcium silicateboard using wire (No. 18recommended) inserted at 50 mm (2 in.)intervals through the board andtightened by twisting at the back.

7 The individual pipe sections are to bemounted so that the highest point of theexposed surface is in the same plane asthe exposed flat surface of a normalsurface.

8 The space between the concaveunexposed surface of the test sampleand the surface of the calcium silicatebacking board is to be left void.

9 The void space between the top of theexposed test surface and the bottomedge of the sample holder frame is to befilled with a high temperature insulatingwool if the width of the pipe segmentsextend under the side edges of thesample holding frame.

4/6.15.10 Testing On Board After InstallationPiping systems are to be subjected to a hydrostatictest pressure of not less than 1.5 times the designpressure to the satisfaction of the Surveyor.

For piping required to be electrically conductive,earthing is to be checked and random resistancetesting is to be conducted to the satisfaction of theSurveyor.

4/6.17 Material of Valves and Fittings

4/6.17.1 GeneralThe physical characteristics of such material are to bein accordance with the applicable requirements ofSection 2/2 or other such appropriate materialspecifications as may be approved in connection witha particular design for the stresses and temperaturesto which they may be exposed. Manufacturers are tomake physical tests of each melt and, upon request,are to submit the results of such tests to the Bureau.

4/6.17.2 Forged or Cast SteelIn any system, forged or cast steel may be used in theconstruction of valves and fittings for all pressuresand temperatures. Consideration is to be given to thepossibility of graphite formation in the followingsteels: Carbon steel above 425C (800F); carbon-molybdenum steel above 468C (875F); chrome-molybdenum steel (with chromium under 0.60%)above 524C (975F).

4/6.17.3 Cast IronFor temperatures not exceeding 232C (450F), castiron of the physical characteristics specified in 2/2.17may be used in the construction of valves and fittings,except in locations for which it is specificallyprohibited elsewhere in the Rules.

4/6.17.4 Ductile (Nodular) IronNodular-iron applications for valves will be speciallyconsidered when the material has an elongation of notless than 12% in 50 mm (2 in.) and where thetemperature does not exceed 343C (650F). See2/2.15.

4/6.17.5 Brass and BronzeBrass or bronze having the physical characteristics asspecified in Section 2/2 may be used in theconstruction of valves and fittings intended fortemperatures up to 208C (406F). For temperaturesgreater than 208C (406F) but not in excess of 288C(550F) high-temperature bronze is to be used and thechemical and physical characteristics are to besubmitted for approval. For use in salt water systems,see also 4/6.13.4.

Valves, fittings and flanges of nonferrous materialmay be attached to nonferrous pipe by an approvedsoldering method. For pressures up to 6.9 bar (7kgf/cm2, 100 psi) and temperatures not exceeding93C (200F) ordinary solder may be used, but forhigher pressures and temperatures the method and thequality of solder to be used will be considered foreach case.

4/6.17.6 PlasticRigid plastic compounds for valves and fittings inplastic piping systems will be considered for Group IIpiping systems. The design pressure and temperaturetogether with the physical characteristics of thematerial verifying compliance with the requirementsof 4/6.15 are to be submitted in all cases.

4/6.19 Valves

4/6.19.1 Generala Standard Valves Valves constructed and

tested in accordance with a recognized standard maybe used subject to compliance with 4/6.19.3.

b Non-Standard Valves All other valves notcertified by the manufacturer as being in accordancewith a recognized standard may be accepted based onevidence verifying their suitability for the intendedservice. Acceptable evidence includes testing oranalysis demonstrating adequacy including bothstructural and material capability aspects. Drawingsof such valves showing details of construction andmaterials are to be submitted for review, as well asbasis for valve pressure rating, such as designcalculations or appropriate burst test data.


4/6.19.2 ConstructionAll valves are to close with a right hand (clockwise)motion of the handwheel when facing the end of thestem and are to be either of the rising-stem type orfitted with an indicator to show whether the valve isopen or closed.

All valves of Group I piping systems havingnominal diameters exceeding 50 mm (2 in.) are tohave bolted, pressure seal, or breech lock bonnets andflanged or welding ends. Welding ends are to be thebutt weld type except that socket weld ends may beused for valves having nominal diameters of 80 mm(3 in.) or less up to and including 39.2 bar (40.0kgf/cm2) pressure rating class (ASME 600 Class), andfor valves having nominal diameters of 65 mm (2.5in.) or less up to and including 98.1 bar (100 kgf/cm2)pressure rating class (ASME 1500 Class).

All cast iron valves are to have bolted bonnets orare to be of the union bonnet type. For cast ironvalves of union bonnet type, the bonnet ring is to beof steel, bronze, or malleable iron.

Stems, discs or disc faces, seats, and otherwearing parts of valves are to be of corrosionresistant materials suitable for intended service.

Valves are to be designed for the maximumpressure to which they will be subjected. The designpressure is to be at least 3.4 bar (3.5 kgf/cm2, 50 psi).Valves used in open systems, such as vent and drainlines, (for example, level gauge and drain cocks) maybe designed for a pressure below 3.4 bar (3.5 kg/cm2,50 psi) subject to the requirements of 4/6.19.1. Largefabricated ballast manifolds which connect linesexceeding 200 mm (8 in.) nominal pipe size may beused when the maximum pressure to which they willbe subjected does not exceed 1.7 bar (1.75 kgf/cm2,25 psi).

All valves for Group I piping systems and valvesintended for use in oil lines are to be constructed sothat the stem is positively restrained from beingscrewed out of the body (bonnet). Plug valves,butterfly valves, and valves employing resilientmaterial will be subject to special consideration.Valve operating systems for all valves which cannotbe manually operated are to be submitted forapproval.

4/6.19.3 Hydrostatic Test and IdentificationAll valves are to be subjected by the manufacturer toa hydrostatic test at a pressure equal to that stipulatedby the American National Standards Institute or otherrecognized standard. They are to bear the trademarkof the manufacturer legibly stamped or cast on theexterior of the valve and the primary pressure ratingat which the manufacturer identifies the valve asmeeting the requirements of the standards.

4/6.21 Pipe Fittings

4/6.21.1 GeneralAll fittings in Group I piping are to have flanged orwelded ends in sizes over 89 mm O.D. (3 in. NPS).Screwed fittings may be used in Group I pipingsystems provided the temperature does not exceed496C (925F) and the pressure does the exceed themaximum pressure indicated below for the pipe size.

Pipe Sizemm O. D. (in. NPS)

Maximum Pressurebar (kgf/cm2, psi)

above 89 (3) not permitted inGroup I piping service

above 60 (2) through 89 (3) 27.6 (28.10, 400)

above 33 (1)through 60 (2)

41.4 (42.2, 600)

above 27 (0.75)through 33 (1)

82.8 (84.4, 1200)

27 (0.75)and smaller

103 (105.5, 1500)

Flared, flareless, and compression fittings may beused for tube sizes not exceeding 60 mm O.D. (2 in.NPS) in Group I piping. In Group II piping, screwedfittings, flared, flareless, and compression tubefittings will be accepted without size limitations.Flared fittings are to be used for flammable fluidsystems except that both flared and flareless fittingsof the non-bite type may be used when the tubingsystem is of steel or nickel-copper or copper-nickelalloys. Only flared fittings are to be used whentubing for flammable fluid systems is of copper orcopper-zinc alloys. See 4/6.67.4 for hydraulicsystems.

4/6.21.2 Hydrostatic Test and IdentificationAll fittings are to be subjected by the manufacturer toa hydrostatic test at a pressure equal to that stipulatedby the American National Standards Institute or otherrecognized standard. They are to bear the trademarkof the manufacturer legibly stamped or cast on theexterior of the fitting and also the primary pressurerating at which the manufacturer guarantees the fittingto meet the requirements of the standards.

4/6.21.3 Non-Standard FittingsFittings which are not certified by the manufacturer asbeing in accordance with a recognized standard maybe accepted based on evidence verifying theirsuitability for the intended service. Acceptableevidence include testing or analysis demonstratingadequacy including both structural and materialcapability aspects. Drawings of such fittings showingdetails of construction, material and designcalculations or test results are to be submitted forreview.


4/6.22 Welded Non-Standard Valves andFittings

Non-Standard steel valves and fittings fabricated bymeans of fusion welding are to comply also with therequirements of Section 2/3. However, after amanufacturer's procedure in the fabrication ofequipment of this kind has been demonstrated by teststo the satisfaction of a Surveyor to the Bureau,subsequent tests on the product need not bewitnessed, but the manufacturer's guarantee that theRules are complied with will be accepted as for othervalves and fittings which conform to standards of theAmerican National Standards Institute or otherrecognized standards.

4/6.23 Flanges

4/6.23.1 GeneralFlanges are to be designed and fabricated inaccordance with a recognized standard. Slip-onflanges from flat plate may be substituted for hubbedslip-on flanges in Group II piping systems.

4/6.23.2 Group I Piping FlangesIn Group I piping, flanges may be attached to thepipes by any of the following methods appropriate forthe material involved:

a Steel Pipe Over 60 mm O.D. (2 in. NPS)steel pipes are to be expanded into steel flanges, orthey may be screwed into the flanges and seal-welded. They may in all cases be attached by fusionwelding in compliance with the requirements of2/3B.9. Smaller pipes may be screwed without seal-welding but oil lines are, in addition, to be expandedinto the flanges in order to insure uniformly tightthreads.

b Nonferrous Pipe In Group I, nonferrous pipesare to be brazed to composition metallic or steelflanges, and in sizes of 60 mm O.D. (2 in. NPS) andunder they may be screwed.

4/6.23.3 Group II Piping FlangesSimilar attachments are also to be used in Group IIpiping. However, modifications are permitted forwelded flanges as noted in 2/3B.9.3 and 2/3B.9.4 andscrewed flanges of suitable material may be used inall sizes.

4/6.23.4 Group II Plastic Piping FlangesRigid plastic compounds for flanges in plastic pipingsystems will be considered for Group II pipingsystems. The design pressure and temperaturetogether with the physical characteristics of thematerial are to be submitted in all cases.

4/6.25 Sea Inlets and Overboard Discharges

4/6.25.1 InstallationPiping connections bolted to the shell plating are tohave the bolt heads countersunk on the outside andthe bolts threaded through the plating. Where areinforcing ring of sufficient thickness is welded tothe inside of the shell, studs may be used.

4/6.25.2 Valve Connections to ShellPipe connections fitted between the shell and thevalves are to be of substantial construction (i.e., pipewall thickness is to be equal to the shell platingthickness but need not be greater than extra heavy)and as short as possible. Wafer type valves are not tobe used for any connections to the vessel's shellunless specially approved. Lug type butterfly valvesused as shell valves are to have a separate set of boltson each end of the valve so that the inboard end maybe disconnected with the valve closed to maintain itswatertight integrity.

4/6.25.3 MaterialsAll shell fittings and valves required by 4/6.27 and4/6.29 are to be of steel, bronze or other approvedductile material. Valves of ordinary cast iron orsimilar material are not acceptable. The use ofnodular iron, also known as ductile iron orspheroidal-graphite iron, will be accepted providedthe material has an elongation not less than 12% in 50mm (2 in.). All pipes to which this subsection refersare to be of steel or other equivalent material, subjectto special approval.

4/6.25.4 Shell ReinforcementOverboard discharges are to have spigots extendingthrough the shell plate and doubling plate where fittedbut need not project beyond the outside surface of thevessel.

4/6.25.5 Common Overboard DischargeIn general, various types of systems which dischargeoverboard are not to be interconnected withoutspecial approval; that is closed pumping systems,deck scuppers, gravity drains, etc. are not to have acommon overboard discharge

4/6.27 Machinery and Pumping Systems

4/6.27.1 Valves RequiredPositive closing valves are to be fitted at the shell ininlet and discharge piping. The controls are to bereadily accessible and are to be provided withindicators showing whether the valves are open orclosed.


4/6.27.2 Sea ChestsThe location of sea chests is to be such as to minimizethe probability of blanking off the suction andarranged so that the valves may be operated from thefloors or gratings. Power-operated sea valves are tobe arranged for manual operation in the event of afailure of the power supply.

Sea chests are to be fitted with strainer plates atthe shell. The strainers are to have a clear area of atleast 1.5 times the area of the sea valves. Efficientmeans are to be provided for clearing the strainers.

4/6.29 Scuppers and Drains

4/6.29.1 Discharges through the ShellDischarges led through the shell either from spacesbelow the freeboard deck or from withinsuperstructures and deckhouses on the freeboard deckfitted with doors complying with the requirements of3/18.7.1 are to be fitted with efficient and accessiblemeans for preventing water from passing inboard.

Normally, each separate discharge is to have oneautomatic non-return valve with a positive means ofclosing it from a position above the freeboard deckexcept as follows.

a Where the vertical distance from the summerloadline to the inboard end of the discharge pipeexceeds 0.01L, the discharge may have two automaticnon-return valves without positive means of closing,provided that the inboard valve is always accessiblefor examination under service conditions. Theinboard valve is to be above the tropical loadwaterline. If this is not practicable, then, provided alocally controlled stop valve is interposed betweenthe two non-return valves, the inboard valve need notbe fitted above the tropical load waterline.

b Where the vertical distance exceeds 0.02L, asingle automatic non-return valve without positivemeans of closing may be accepted provided the valveand discharge outlet are located above the deepestload waterline.

L is defined in Section 3/1.The means for operating the positive-action valve

is to be readily accessible and provided with anindicator showing whether the valve is open orclosed.

4/6.29.2 Scuppers and Discharges below theFreeboard Deck

Scuppers and discharge pipes originating at any leveland penetrating the shell either more than 450 mm(17.5 in.) below the freeboard deck or less than 600mm (23.5 in.) above the summer load waterline are tobe provided with a non-return valve at the shell. Thisvalve, unless required by 4/6.29.1, may be omitted ifthe piping has a wall thickness at least equal to thethickness of the shell plating or extra-heavy pipe,whichever is less.

4/6.29.3 Scuppers from Superstructures orDeckhouses

a Enclosed Cargo Spaces Drainage of enclosedcargo spaces situated on the bulkhead deck or thefreeboard deck is to be provided with the following:

1 Where the summer freeboard is suchthat the deck edge of the space beingdrained is not immersed when the shipheels 5 degrees, the drainage is to be bymeans of a sufficient number ofscuppers of suitable size dischargingdirectly overboard in accordance with4/6.29.1.

2 Where the summer freeboard is suchthat the deck edge of the space beingdrained is immersed when the ship heels5 degrees, the drainage of the enclosedcargo spaces is to be led to a suitablespace, or spaces, of adequate capacity,having a high water level alarm andprovided with suitable arrangements fordischarge overboard. In addition thesystem is to be designed such that;a the number, size and disposition of

the scuppers are to preventunreasonable accumulation of freewater;

b the pumping arrangements are totake into account the requirementsfor any fixed, pressurized, waterspraying, fire extinguishing system;

c water contaminated with oil orother dangerous substances is notdrained to machinery spaces orother spaces where sources ofignition may be present; and

d where the enclosed cargo space isprotected by a carbon dioxide fireextinguishing system the deckscuppers are fitted with means toprevent the escape of thesmothering gas.

b Open Superstructures and DeckhousesScuppers leading from superstructures or deckhousesnot fitted with doors complying with the requirementsof 3/18.7.1 are to be led overboard.

4/6.29.4 Craft Receiving Subdivision LoadlinesFor craft receiving subdivision loadlines, thebulkhead deck is to apply to provisions given in4/6.29.1 when it is higher than the freeboard deck.


4/6.31 Cooler Installations External to the Hull

4/6.31.1 GeneralThe inlet and discharge connections of externalcooler installations are to be in accordance with4/6.25.1 through 4/6.25.3 and 4/6.27.1 except thatwafer type valves will be acceptable.

4/6.31.2 Keel Cooler InstallationsThe positive closing valves required by 4/6.31.1 neednot be provided if the keel (skin) cooler installation isintegral with the hull. To be considered integral withthe hull, the installation is to be constructed such thatchannels are welded to the hull with the hull structureforming part of the channel, the channel material is tobe at least the same thickness and quality as thatrequired for the hull and the forward end of the cooleris to be faired to the hull with a slope of not greaterthan 4 to 1.

If positive closing valves are not required at theshell, all flexible hoses or joints are to be positionedabove the deepest load waterline or be provided withan isolation valve.

4/6.31.3 Grid Cooler InstallationsWhere grid coolers are used, if the shell penetrationsare not fully welded, the penetration is to be encasedin a watertight enclosure.

4/6.33 General Arrangement of Bilge Systems

A pumping system is to be provided in all craftcapable of pumping from and draining anycompartment when the craft is on an even keel andeither upright or listed 5 degrees. For this purposewing suctions will often be necessary, except innarrow compartments at the ends of the craft.Arrangements are to be made whereby water in thecompartment will drain to the suction pipes. Efficientmeans are to be provided for draining water from alltank tops and other watertight flats. Peak tanks, chainlockers and decks over peak tanks may be drained byejectors or hand pumps.

4/6.35 Bilge Pumps

4/6.35.1 Number of Pumpsa Monohull Craft

1 20 m (65 ft) or Greater Each monohullcraft 20m (65 ft) in length or greater isto be provided with two power-drivenbilge pumps, one of which may beattached to the propulsion unit.

2 Under 20 m (65 ft) Each monohullcraft under 20 m (65 ft) in length is tobe provided with at least one fixedpower-driven pump, which may be anattached unit, and one portable handpump.

b Multihull Craft1 20 m (65 ft) or Greater On multihull

craft 20 m (65 ft) in length or greater,each hull is to be provided with at leasttwo power-driven bilge pumps, unlessa bilge pump in one hull is capable ofpumping bilge in the other hull. Atleast one bilge pump in each hull is tobe an independently-driven pump.

2 Under 20 m (65 ft) On multihull craftunder 20 m (65 ft) in length, each hullis to be provided with at least one fixedpower-driven bilge pump, which maybe an attached unit, unless the system isarranged such that a single fixedpower-driven bilge pump is capable oftaking suction from either hull. Ineither case, one portable hand pump isalso to be provided.

c Alternative Arrangement - SubmersiblePumps As an alternative to a or b, an arrangementutilizing submersible pumps may be utilized. See4/6.41.

4/6.35.3 CapacityThe capacity, Q, of each pump is to be in accordancewith the following:

Craft Length, L Minimum Capacity per Pump,Q

Below 20 m (65 ft.) 5.5 m3/hr (25 gpm)(hand pump 5 gpm, 1.13 m3/hr)

20 m (65 ft.) or greaterbut below 30.5 m (100 ft.)

11 m3/hr (50 gpm)

30.5 m (100 ft.) or greaterbut below 45.7 m (150 ft.)

14.33 m3/hr (66.6 gpm)

45.7 m (150 ft.) and greater 5.66 d2/103 m3/hr(16.1 d2 gpm)

whered = required diameter of main bilge line suction,

mm or in. See 4/6.39.5

When more than two pumps are connected to thebilge system, their arrangement and aggregatecapacity are not to be less effective.

4/6.35.4 Centrifugal PumpsWhere centrifugal pumps are installed, suitable meansfor priming are to be provided.

4/6.35.5 Independent Power Bilge PumpsSanitary, ballast and general service pumps may beaccepted as independent power bilge pumps,provided they are of the required capacity and arefitted with the necessary control valves required by4/6.39.1 for pumping bilges. Pumps used forpumping oil or other flammable or combustibleliquids are not to be used as bilge pumps.


4/6.39 Bilge and Ballast Piping

4/6.39.1 GeneralThe arrangement of the bilge and ballast pumpingsystems is to be such as to prevent the possibility ofwater or oil passing into the cargo and machineryspaces, or from one compartment to another, whetherfrom the sea, water ballast or oil tanks. The bilge andballast mains are to have separate control valves atthe pumps.

4/6.39.2 InstallationBilge or ballast pipes, where permitted to passthrough compartments intended for the carriage ofoil, are to be of either steel or wrought iron.

Where bilge pipes in way of deep tanks are notled through a watertight or oiltight tunnel, the bilgelines are to be of steel and extra heavy. Similarly,where ballast pipes in way of deep tanks, other thanballast tanks, are not led through a watertight oroiltight tunnel, the ballast lines are to be of steel andextra heavy. For both bilge and ballast piping, thenumber of joints is to be kept to a minimum and areto be welded or extra heavy flanged. The pipingwithin a deep tank is to be installed to take care ofexpansion. A non-return valve is to be fitted at theopen end of bilge pipes.

4/6.39.3 Manifolds, Cocks and Valvesa General All manifolds, cocks and valves in

connection with the bilge pumping arrangement are tobe in positions which are accessible at all times underordinary circumstances. All valves in the machineryspace controlling the bilge suctions from the variouscompartments are to be of the stop-check type. Ifvalves are fitted at the open ends of pipes, they are tobe of the non-return type.

b Controls for Ballast Tank Valves Ballast tankvalves are to be arranged so they will remain closedat all times except when ballasting. For this purpose,manual screw thread operated valves, positiveholding arrangements for butterfly type valves orother equivalent arrangements may be used. Whereinstalled, remote controlled valves are to be arrangedso they will close and remain closed upon loss ofcontrol power, or will remain in their last position andare provided with a readily accessible manual meansof operation in case of loss of power to the valvecontrol system. Remote control of bilge and ballastvalves is to be clearly marked at the control stationand means are to be provided to indicate whether thevalve is open or closed.

4/6.39.4 StrainersBilge lines in machinery spaces other than emergencysuctions are to be fitted with strainers easilyaccessible from the floor plates and are to havestraight tail pipes to the bilges. The ends of bilge

lines in other compartments are to be fitted withsuitable strainers having an open area of not less thanthree times the area of the suction pipe. In additionstrainers are to be fitted in accessible positionsbetween the bilge manifolds and the pumps.

4/6.39.5 Size of Bilge SuctionsThe least internal diameter of bilge suction pipes is tobe that of the nearest commercial size within 6 mm(0.25 in.) of the diameter determined by the followingequations.

a Main Line For the diameter of main bilge linesuctions and direct bilge suctions to the pumps:

( )d L B D= + +25 168. mm

( )d L B D= + +1 2500 in.

b Branch Lines For the equivalent diameter ofthe combined branch suctions to a compartment:

( )d c B D= + +25 2 16. mm

( )d c B D= + +1 1500 in.

d = internal diameter of pipe in mm or inL = length of craft as defined in Section 3/1

in m or ftB = for monohull craft, breadth of craft as

defined in Section 3/1 in m or ftfor multihull craft, the breadth of a hullat or below the design waterline

c = length of compartment in m or ftD = molded depth to bulkhead or freeboard

deck in m or ft except that, for the mainline, in a craft having an enclosed cargospace on the bulkhead or freeboard deckwhich is internally drained in accordancewith 4/6.29.3a2 and which extends forthe full length of the ship, D is to bemeasured to the next deck above thebulkhead or freeboard deck. Where theenclosed cargo spaces cover a lesserlength, D is to be taken as a moldeddepth to the bulkhead or freeboard deckplus lh/L where l and h are aggregatelength and height respectively of theenclosed cargo spaces.

c Main Line Reduction Where engine roombilge pumps are fitted primarily for drainage withinthe engine room, L may be reduced by the combinedlength of the cargo holds. In such cases, the crosssectional area of the bilge main is not to be less thantwice the required cross sectional area of the engineroom branch lines.


d Alternate Size Requirements For craft below45.7 m (150 ft.) in length the bilge main sizes may bein accordance with the following in lieu of 4/6.39.5a.

Craft Length Minimum Pipe Size (I.D.)

Below 20 m (65 ft.) 25 mm (1 in.)

20 m (65 ft.) or greater butbelow 30.5 m (100 ft.)

32 mm (1.25 in)

30.5 m (100 ft) or greater butbelow 45.7 m (150 ft)

38 mm (1.5 in.)

e Size Limits For craft of 45.7 m (150 ft) inlength or greater, no main suction piping is to be lessthan 63 mm (2.5 in.) internal diameter. For all craft,no branch piping need be more than 100 mm (4 in.)I.D., nor is it to be less than 25 mm (1 in.) I.D..

4/6.39.6 Gravity DrainsGravity drains that penetrate the main machineryspace watertight bulkheads below the freeboard deckand terminate within the main machinery space are tobe fitted with a valve operable from above thefreeboard deck or with quick-acting, self-closingvalves. The valve should preferably be located in themain machinery space. When gravity drains fromother spaces are terminated in cargo holds, the cargohold bilge well is to be fitted with a high level alarm.Gravity drains which terminate in spaces which areprotected by fixed gas extinguishing systems are to befitted with means to prevent the escape ofextinguishing medium.

4/6.40 Emergency Bilge Suctions

An emergency bilge suction is to be fitted for eachmachinery space containing a propulsion primemover. This suction is to be provided from thelargest suitable pump in the engine room except arequired bilge pump. The area of the direct bilgesuction pipe is to be equal to the full suction inlet ofthe pump selected. A suitable overboard dischargeline is to be provided and the means of control of thedirect bilge suction is to be readily accessible and solocated to provide rapid operation. The emergencybilge suction is to be provided with suitable non-return valves.

4/6.41 Submersible Bilge Pumps

In bilge pumping arrangements where a bilge main isnot provided, then, with the exception of the spacesforward of public spaces and crew accommodation, atleast one fixed submersible pumps is to be providedfor each space. In addition, at least one portablepump is to be provided and be supplied from theemergency supply, if electric, for use on individualspaces.

The total capacity, Qt, of the fixed submersiblebilge pumps for each hull is not to be less than 2.4times the pump capacity, Q, determined in 4/6.35.3.

The capacity, Qn, of each submersible pump is notto be less than:

( )Q Q Nn t= −1 m3/hr (gpm), with a minimum of

8 m3/hr (35 gpm)N = number of submersible pumps

4/6.42 Bilge Alarms

Any unattended space for which bilge pumpingarrangements are required is to be provided with abilge alarm.

4/6.43 Vent Pipes

4/6.43.1 GeneralExcept for comparatively small compartments that arenot fitted with a fixed means of drainage, vent pipesare to be fitted to all tanks, cofferdams, voids, tunnelsand compartments which are not fitted with otherventilation arrangements. In all craft the structuralarrangement in double-bottom and other tanks is to besuch as to permit the free passage of air and gasesfrom all parts of the tanks to the vent pipes. Eachtank is to be fitted with at least one vent pipe, whichis to be located at the highest part of the tank. Ventpipes are to be arranged to provide adequate drainageunder normal conditions.

4/6.43.2 HeightWhere air pipes extend above the freeboard orsuperstructure decks, the exposed parts of the pipesare to be of at least Standard thickness; the heightfrom the deck to the point where water may haveaccess below is to be at least 760 mm (30 in.) on thefreeboard deck and 450 mm (17.5 in.) on thesuperstructure deck. Where these heights mayinterfere with the working of the vessel, a lowerheight may be approved, provided that the closingarrangements and other circumstances justify a lowerheight.

As an alternative, the vent pipes may be carriedout through the side of the vessel. The pipe is toextend to a point close to the weather deck and a non-return valve is to be located as close as practicable tothe shell. Other means will be considered providedthey ensure equivalent protection against flooding.

4/6.43.3 SizeVent pipes are to have a minimum internal diameternot less than 38 mm (1.5 in.) and not less than theinternal diameter of the fill line. Where tanks are tobe filled by pump pressure, the aggregate area of thevents in the tank is to be at least 125% of the effectivearea of the filling line, except that when overflows are


fitted, the area of the overflow is to be at least 125%of the effective area of the filling line and the ventsneed not exceed the above minimum size.

Notwithstanding the above, the pump capacityand pressure head are to be considered in the sizingof vents, and overflows; when high capacity and/orhigh head pumps are used, calculations demonstratingthe adequacy of the vent and overflows are to besubmitted.

4/6.43.4 LocationVents for compartments required for subdivision(such as double bottom or wing spaces) are to be ledto above the freeboard or bulkhead deck. Inaddition, vents for ballast tanks, fuel oil tanks, andthose cofferdams adjacent to fuel oil tanks are to beled to the weather. Vents for other tanks mayterminate within the machinery space but are to belocated so as to preclude the possibility ofoverflowing on electrical equipment, engines orheated surfaces.

4/6.43.5 Vent OutletsAll vent and overflow pipes on the open deck are toterminate by way of return bends.

a Fuel Oil Tank Vents Vent outlets from fueloil tanks are to be fitted with corrosion-resistantflame screens having a clear area through the mesh ofnot less than the required area of the vent pipe.

b Weathertight Closure Satisfactory means,permanently attached, are to be provided for closingthe openings of the vent pipes. The means of closingvent pipes is to be weather tight. Closing devices areto be automatic if, while the craft is at its draughtcorresponding to summer loadline, or timber summerload line where assigned, the openings of the air pipessubmerge at angles up to 40 degrees or up to a lesserangle which may be accepted on the basis of stabilityrequirements. Automatic devices are also to be fittedon vents for craft designed for the carriage of deckcargoes which may prevent access to the vents.

4/6.45 Overflow Pipes

Overflow pipes discharging through the side of thecraft are to be located as far above the deepestloadline as practicable and are to be provided withnon-return valves located on the craft's side. Wherethe overflow does not extend above the freeboarddeck, there is to be provided in addition an efficientand accessible means for preventing water frompassing inboard. Such means may consist of a non-return valve located in an accessible position abovethe deepest loadline.

Where it is impracticable to locate the valve in anaccessible position, one non-return valve withpositive means for closing from an accessible positionabove the freeboard or bulkhead deck will be

acceptable, provided there are suitable arrangementsto insure the valve not being closed by unauthorizedpersons and provided a notice is posted in aconspicuous place at the operating station to theeffect that the valve is never to be closed except asmay be required in an emergency.

Overflow pipes from combustible and flammableliquid tanks are to be led to an overflow tank ofadequate capacity or to a storage tank having spacereserved for overflow purposes. An alarm device isto be provided to give warning when the liquidreaches a predetermined level in the overflow tank.The sight glasses are to be fitted only in verticalsections of overflow pipes.

When overflows from the tanks in more than onewatertight subdivision are connected to a commonheader below the freeboard or bulkhead deck, thearrangement is to be such as to prevent fore-and-aftflooding of one watertight bulkhead subdivision fromanother in the event of damage.

4/6.47 Sounding

4/6.47.1 GeneralAll tanks are to be fitted with a suitable means ofdetermining the level of the liquid therein. Suchmeans may be sounding pipes, gauge glasses, or otherapproved level indicating systems or devices.

Compartments, including cofferdams and pipetunnels, which are not readily accessible are to befitted with sounding pipes if the compartment isadjacent to the sea or has pipes carrying liquidspassing through it.

4/6.47.2 Sounding PipesSounding pipes are not to be less than 38 mm (1.5 in.)inside diameter. They are to be led as straight aspossible from the lowest part of the tank orcompartment to the bulkhead deck or to a positionwhich is always accessible. If sounding pipesterminate below the freeboard deck, they are to beprovided with means for closing in the followingmanner:

a Oil Tanks Quick-acting, self-closing gatevalves are required.

b Other Tanks A screw cap secured to the pipewith a chain or a gate valve is required.

Provision is to be made to prevent damaging thecraft's plating by the striking of the sounding rod. Ingeneral sounding pipes are not to pass through bilgewells, but if this is not practicable, the pipe is to be atleast extra-heavy in the bilge well. Sounding pipesfor combustible or flammable fluids are not toterminate in accommodation spaces.


c Ignition of Spillage Sounding pipes for fueloil tanks are not to terminate in any space where therisk of ignition of spillage may exist. In particular,they are not to not terminate in machinery spaces orin close proximity to internal combustion engines,generators, electric equipment or surfaces withtemperatures in excess of 220C (428F) in otherspaces. Where it is impracticable to do otherwise,sounding pipes from fuel oil tanks may terminate inmachinery spaces provided the following are met:

1 The sounding pipes terminate inlocations remote from ignition hazardsor effective precautions such asshielding are taken to prevent fuel oilspillage from coming into contact with asource of ignition; and

2 The terminations of sounding pipes arefitted with quick-acting, self-closinggate valves and with a small diameterself-closing test cock or equivalentlocated below the gate valve is to beprovided for the purpose of ascertainingthat fuel oil is not present in thesounding pipe before the gate valve isopened. Provisions are to be made so asto prevent spillage of fuel oil throughthe test cock from creating an ignitionhazard; and

3 An approved level gauge is provided.For oil tanks other than double bottoms,the oil level gauge may be omittedprovided an overflow system is fitted.The oil level gauge may also be omittedfor craft less than 500 gross tons.

4/6.47.3 Gauge GlassesTanks may be fitted with gauge glasses, provided thegauge glasses are fitted with a valve at each end andadequately protected from mechanical damage.

Gauge glasses for tanks containing flammable orcombustible liquids are to be of the flat glass typehaving approved self-closing valves at each end. Forhydraulic oil tanks located in spaces other thancategory A machinery spaces, cylindrical gaugeglasses with approved self closing valves at each endwill be acceptable provided such spaces do notcontain internal combustion engines, generators,major electrical equipment or piping having a surfacetemperature in excess of 220 C (428F). Gaugeglasses are not to be used for fuel oil with a flashpoint below 43C (109F).

Gauge glasses for tanks integral with the shellwhich are located below the deepest load waterlineare to be of the flat glass type and have approvedself-closing valves at each end.

4/6.47.4 Level Indicating Systems and DevicesWhere a level indicating device or system is providedfor determining the level in a tank containingflammable or combustible liquid, failure of thedevice/system is not to result in the release of thecontents of the tank through the device. If anoverflow is not fitted, means are also to be providedto prevent overfilling of the tank in the event ofmalfuction of the indicating device/system.

4/6.49 Fuel Oil Piping Systems

4/6.49.1 General Arrangementa Tanks As far as practicable, fuel oil tanks are

to be part of the craft’s structure and located outsideof Category A machinery spaces. Where fuel oiltanks, other than double bottom tanks, are necessarilylocated adjacent to or within a Category A machineryspace, at least one of their vertical sides is to becontiguous to the machinery space boundaries, andpreferably have a common boundary with the doublebottom tanks, if fitted. The area of the tank boundarycommon with the machinery spaces is to be kept to aminimum. Where such tanks are situated within theboundaries of a Category A machinery space, they arenot to contain fuel oil having a flash point of 60C(140F) or less and they are to be made of steel orequivalent material.

Tanks containing fuel oil are to be separated frompassenger, crew, and baggage compartments byvapor-proof enclosures or cofferdams which aresuitably ventilated and drained. Fuel oil is not to becarried forward of public spaces and crewaccommodation.

In general, the use of free standing fuel oil tanks isto be avoided. Where permitted, they are to beplaced in an oil tight spill tray of ample size withadequate means of drainage in accordance with4/6.7.13.

b Spillage No fuel oil tank is to be situatedwhere spillage or leakage therefrom can constitute ahazard by falling on heated surfaces. Precautions areto be taken to prevent any oil that may escape underpressure during inspection or maintenance of anypump, filter or heater from coming into contact with asource of ignition as defined in 4/1.17.9.

4/6.49.2 Piping, Valves and FittingsFuel oil pipes, valves and fittings are to be of steel orother approved materials.

4/6.49.3 Oil Heating Arrangementsa Oil Heaters Where heaters are provided in

fuel oil systems they are to be fitted with atemperature control and either a high temperaturealarm or a low flow alarm, except where themaximum temperature of the heating medium doesnot exceed 220C (428F).


Where electric heaters are fitted they are to bearranged to de-energize automatically when the oillevel falls to a predetermined height to ensure that theheating elements are permanently submerged duringoperation. In addition, a safety temperature switchwith a manual reset independent from the automaticcontrol sensor is to be provided to cut off the electricpower supply in order to avoid a surface temperatureof 220C (428F) or above.

b Tanks Unless specially approved otherwise,fuel oil in storage tanks is not to be heated totemperatures within 10C (18F) below flash point ofthe fuel oil.

Where heating arrangements are provided forsettling and service tanks the control and alarmrequirements of 4/6.49.3a are applicable.

c Piping Arrangement As far as practicable, allparts of the oil fuel system containing heated oilunder pressure exceeding 1.8 bar (1.8 kgf/cm2, 26psi) are not to be placed in a concealed position suchthat defects and leakage cannot readily be observed.The machinery spaces in way of such parts of the oilfuel system are to be adequately illuminated.

4/6.49.4 Fuel Oil PurifiersFuel oil purifiers for heated oil are to be placed in aseparate room or rooms reserved for the purifiers andtheir heaters. If it is impracticable to locate thepurifiers in a separate room, special considerationwill be given with regard to location, containment ofpossible leakage and shielding.

4/6.51 Fuel-oil Transfer and Filling

4/6.51.1 GeneralWhere fuel oil transfer arrangements are furnished,two transfer pumps are to be provided and one ofthem is to be independent of the main engine. Thefuel oil pumping arrangements are to be distinct fromthe other pumping systems as far as practicable, andthe means provided for preventing dangerousinterconnection in service are to be thoroughlyeffective. Where daily service fuel oil tanks are filledautomatically or by remote control, means are to beprovided to prevent overflow spillage.

4/6.51.2 Pipes in Oil TanksOil pipes and other pipes, where passing through oiltanks, are to be of wrought iron or steel, except thatother materials may be considered where it isdemonstrated that the material is suitable for theintended service. All packing is to be of acomposition not affected by oil.

4/6.51.3 Control Valves or CocksValves or cocks controlling the various suctions areto be located close to the bulkhead where the suctionsenter the machinery spaces and wherever practicable

directly over the gutterway in way of deep andsettling tanks. Pumps, strainers, etc., requiringoccasional examination are to have drip pans.

4/6.51.4 Valves on Oil TanksWhere pipe lines emanate from oil tanks at such alevel that they will be subjected to a static head of oilfrom the tank, they are to be fitted with positiveclosing valves located at the tank. Where the oilpiping passes through adjacent tanks, the valverequired above may be located where the pipe runexits the adjacent tank(s) provided the piping in theadjacent tanks is extra-heavy and has all weldedconnections.

If the valves are installed on the outside of thetank, they are not to be of cast iron. The use ofnodular iron, also known as ductile iron orspheroidal-graphite iron, may be used provided thematerial has an elongation not less than 12% in 50mm (2 in.). Arrangements are to be provided forclosing them at the valve and for tanks having acapacity of 500 liters (132 US gal.) or greater, from areadily accessible and safe location outside of thecompartment in which the valve is located.

If the positive closing valve required above issituated in a shaft tunnel or pipe tunnel or similarspace, arrangements for closing may be effected bymeans of an additional valve on the pipe or pipesoutside the tunnel or similar space. If such additionalvalve is fitted in the machinery space, it is to beoperated from a position outside this space.

If the valves are located inside of the tank, theymay be of cast iron and arranged for remote controlonly, but additional valves for local control are to belocated in the machinery space.

Where independent filling lines are fitted, they areto enter at or near the top of the tank; but if this beimpracticable, they are to be fitted with non-returnvalves at the tank.

The valves required above may be remotelyoperated by reach rods or by electric, hydraulic, orpneumatic means. Other means may be specificallyconsidered provided that they are not less effective.The source of power to operate these valves is to belocated outside of the space in which the valves arelocated. The positioning of the valve by either thelocal or remote means is not to interfere with theability of the other means to close the valve.

Materials readily rendered ineffective by heat arenot to be used within the space unless adequatelyprotected. If electric cables are utilized, they are tobe fire resistant meeting the requirements of IEC 331.Hydraulic systems are to be in accordance with 4/6.67for both Class I and II piping systems. For apneumatic system, the air supply may be from asource from within the space provided a separatereceiver complying with the following is locatedoutside the space:


a sufficient capacity to cycle all connectedloads

b fitted with low air pressure alarmc air supply line is fitted with a non-return

valve adjacent to the receiver.

4/6.51.5 Remote Shutdown of PumpsMachinery driving fuel oil transfer pumps, oil fuelunit pumps and other similar fuel pumps are to befitted with remote shutdowns complying with 4/9.5.3.

4/6.51.6 Oil Drain TanksDrain tanks, where fitted, for waste oil, fuel oiloverflows, drains, all oil drip pans, and fuel injectionpiping, etc., are to have air and sounding pipes. Non-return valves are to be fitted in drain lines enteringthe drain tanks except where backflow would notpresent a hazard. Suitable means are to be providedfor pumping out these drain tanks.

Oil tanks not forming a part of the vessel'sstructure, where permitted by 4/6.49.1a, are to havesuitable drip pans with adequate means of drainage inaccordance with 4/6.7.13.

4/6.53 Fuel-Oil Service and Injection Systems

Fuel oil service and injection systems for internal-combustion engines are to be in accordance with4/4.3, 4/4.5 and 4/4.7.

4/6.55 Low-Flash Point Fuels

4/6.55.1 GeneralFuel oils with a flash point of 60C (140F) closed-cupor below may be accepted for the following:

a ships classed for restrictive service withinareas having a climate ensuring that ambienttemperatures of spaces where such fuel oil isstored will not rise within 10C (18F) belowits flash point, may use fuel oil with flashpoint of 60C (140F) or below but not lessthan 43C (110F).

b for emergency generators fuel oil with aflash point of not less than 43C (110F) maybe used. See 4/5A3.5.2.

c for gas turbines, subject to compliance withthe requirements in 4/3.9.4.

4/6.55.2 Fuel HeatingFor oil heating arrangements, see 4/6.49.3.

4/6.55.3 Fuel Oil Tank VentsVent pipes are to extend at least 2.4 m (8 ft.) abovethe weather deck or other effective arrangementswhich have been approved are to be provided. Wherefuel oil with a flash point below 43C (109F) ispermitted in accordance with 4/6.55.1c, the vents areto terminate with approved flame arresters.

4/6.59 Lubricating Oil Systems

4/6.59.1 GeneralThe lubricating systems are to be so arranged thatthey will function satisfactorily under the conditionsspecified in 4/1.21. The lubricating oil piping is to beentirely separated from other piping systems. Inaddition, the requirements of 4/6.49.1b, 4/6.49.2,4/6.49.3 and 4/6.51.4 are applicable.

4/6.59.2 Sight Flow GlassesSight flow glasses may be used in lubricating systemsprovided they are fire resistant.

4/6.59.3 Internal-Combustion EnginesFor internal-combustion engines, see also 4/4.9.

4/6.59.4 Reduction GearsFor reduction gears see also 4/4.9.13

4/6.59.5 Electrical MachineryFor electrical machinery see also 4/5B2.3, 4/5B2.5and 4/5C2.13.

4/6.59.6 Hose ReelsWhere hose reels are used for filling engine orreduction gear sumps with oil, a self-closing valve isto be provided at the end of the filling hose to preventspillage. Suitable arrangements are to be provided toproperly drain and store the hose and reel when not inuse. Hoses are to be approved for oil service and inaccordance with the requirements for burst pressure,fire resistance, reinforcement, and end fittings in4/6.7.11

4/6.59.7 Tank LocationLubricating oils are not to be carried forward ofpublic spaces and crew accommodation.

4/6.61 Cooling Water System

Cooling water systems for internal-combustionengines are to comply with 4/4.11.

4/6.63 Exhaust Piping

4/6.63.1 GeneralAll engine exhaust systems are to be adequate toassure the correct functioning of the machinery andthat safe operation of the craft is not put at risk. Theexhaust pipes are to be water-jacketed or effectivelyinsulated. Exhaust systems are to be so installed thatthe vessel's structure cannot be damaged by heat fromthe systems. Exhaust pipes of several engines or gasturbines are not to be connected together but are to berun separately to the atmosphere unless arranged toprevent the return of gases to an idle engine orturbine. Exhaust lines which are led overboard near


the waterline are to be protected against thepossibility of the water finding its way inboard.Exhaust systems are to be so arranged as to minimizethe intake of exhaust gases into manned spaces, air-conditioning systems, and engine intakes. Exhaustsystems are not to discharge into air-cushion intakes,where provided. Also see 4/4.17 for internal-combustion engines and 4/3.13 for gas turbines.

4/6.63.2 Exhaust System MaterialsMaterials used in the exhaust system are to beresistant to saltwater corrosion, galvanicallycompatible to each other and resistant to exhaustproducts. Plate flanges will be considered where thespecified material is suitable for exhaust pipingpressures and temperatures.

4/6.65 Starting-Air SystemsStarting-air systems for internal-combustion enginesare to comply with 4/4.15.

4/6.67 Hydraulic Systems

4/6.67.1 GeneralThe arrangements for Group I hydraulic pipingsystems are to be in accordance with the requirementsof this section, except that hydraulic systems whichform part of a unit which is independentlymanufactured and assembled and which does notform part of the ship's piping system (such as a crane)are not covered by this section.

Plans showing clearly the arrangements anddetails are to be submitted for review.

Hydraulic pumps, actuators, motors andaccessories are to be suitable for the intended duty,compatible with the working fluid and are to bedesigned to operate safely at full power conditions.In general, the hydraulic fluid is to be non-flammableor have a flash point above 157C (315F).

The requirements for fuel oil systems contained in4/6.49.1b, 4/6.49.2 and 4/6.51.4 are applicable totanks containing hydraulic fluid. See also 4/7.32 and4/8.4.

4/6.67.2 Valvesa General In general, valves are to comply with

the requirements of 4/6.17 and 4/6.19.b Relief Valves Relief valves are to be provided

for the protection of the hydraulic system. Each reliefvalve is to be capable of relieving not less than fullpump flow with a maximum pressure rise of not morethan 10% of the relief valve setting.

4/6.67.3 PipingPiping is to meet the requirements of 4/6.4 and4/6.13, except that mill tests need not be witnessed bythe Surveyor. In such cases, mill certificates are to beprovided which verify the chemical and mechanicalproperties for the pipe.

4/6.67.4 Pipe FittingsFittings and flanges are to meet the requirements of4/6.17, 4/6.21, and 4/6.23, except as follows:

a Split Flanges Split flanges are not to be usedin steering gear systems nor in systems which are vitalto the propulsion or safety of the vessel. Split flangesmay be considered for use in other systems. Wheresplit flanges are permitted they are not to be used tojoin sections of piping, but may be used forconnections to machinery provided the materials andconstruction are suitable for the system designpressure.

b Straight-Thread "O"-Ring ConnectionsStraight-thread "O"-ring type connections may beused for connections to equipment such as pumps,valves, cylinders, accumulators, gages, and hoses.Such connections are not to be used for joiningsections of pipe.

c Tapered Threaded Connections Taperedthreaded connections up to and including 89 mmO.D. (3 in. NPS) may be used without limitation forconnections to equipment such as pumps, valves,cylinders, accumulators, gages, and hoses. Taperedthreaded connections are not to be used in steeringgear systems, controllable pitch propeller systems,and other systems associated with propulsion orpropulsion control, except where permitted by4/6.21.1. Such connections are not to be used forjoining sections of pipe except where permitted by4/6.21.1.

4/6.67.7 Accumulators and Fluid Power CylindersAccumulators are to meet the requirements of Section4/2 of the "Rules for Building and Classing SteelVessels". Each accumulator which may be isolated isto be protected by suitable relief valves. Where a gascharging system is used, a relief valve is to beprovided on the gas side of the accumulator.

Fluid Power Cylinders are to meet therequirements of 4/6.69.

4/6.67.8 Design PressureThe pressure used for determining the strength anddesign of piping and components is not to be less thanthe relief valve setting.

4/6.67.9 Segregation of High Pressure HydraulicUnits

Hydraulic units with working pressures above 15.5bar (15.8 kgf/cm2, 225 psi) installed within amachinery space are to be placed in separate room orrooms or shielded as necessary to prevent any oil oroil mist that may escape under pressure from cominginto contact with surfaces with temperatures in excessof 220C (428F), electrical equipment or other sourcesof ignition. For the purpose of this requirement, ahydraulic unit includes the power pack and allcomponents of the hydraulic piping system.


4/6.69 Fluid Power Cylinders

4/6.69.1 ApplicationHydraulic and pneumatic power cylinders are to be inaccordance with the requirements of this section.Hydraulic steering gear cylinders are to be inaccordance with the requirements of 4/8.3.6.Cylinders forming a part of an independentlymanufactured and assembled unit that do not formpart of ship's piping system are not covered by thissubsection.

4/6.69.2 Cylinders for Group I Piping Systemsa Design The design of hydraulic and

pneumatic power cylinders is to meet therequirements of 4/2.5.1 (for nodular cast iron, use y =0.5), 4/2.9 and 4/2.11 of the "Rules for Building andClassing Steel Vessels", as applicable, with S asdefined in this subparagraph. Welding is to be inaccordance with Section 2/3B. The maximumallowable stress S is not to exceed the following:

U

Aor

Y

B

whereU = minimum specified tensile strength of material

at room temperatureY = minimum specified yield point or yield

strength A & B are as follows:

Rolled orForged Steel

CastSteel

NodularCast Iron

A 3.5 4 5B 1.7 2 3

Alternatively, designs may be accepted on the basisof certified burst test reports. Steel cylinders of otherthan cast construction are to be designed for abursting pressure not less than 4 times the maximumallowable working pressure. Cylinders of cast steelor ductile iron are to be designed for a burstingpressure not less than 5 times the maximum allowableworking pressure.

b Plans and Data to be SubmittedCylinder and head detailsCylinder rod and piston detailsThread standard and dimensionsWelding details and dimensionsLug attachmentsMaterial specifications including minimum tensile,

yield and elongation propertiesDesign pressure and temperatures (minimum and

maximum)Test pressure

c Material The physical and chemicalcharacteristics of materials entering into theconstruction of hydraulic and pneumatic power

cylinders are to be in accordance with the applicablerequirements of Section 2/2 or other such appropriatematerial specification as may be approved inconnection with a particular design. Copies ofcertified mill test reports are to be made available tothe Surveyor upon request. Ordinary cast iron orsimilar materials (elongation less than 12% in 50 mm(2 in.) are not to be used for cylinders which may besubjected to shock loading.

d Hydrostatic Tests1 General Cylinders are to be subjected

to a hydrostatic test. This test need notbe witnessed by the Surveyor.

2 Test Pressure The test pressure appliedis to be not less than 1 ½ times themaximum allowable working pressurefor steel cylinders, and not less thantwice the maximum allowable workingpressure for cast iron and nodular ironcylinders.

4/6.69.3 Cylinders for Group II Piping SystemsHydraulic and pneumatic power cylinders for use inGroup II piping systems may be accepted on the basisof the manufacturer's data indicating pressure ratingand suitability for the intended service.

4/6.71 Fixed Oxygen--Acetylene Installations

4/6.71.1 Cylinder StorageWhere fixed installations consisting of two or morecylinders of each gas are located in enclosed spaces,the cylinders are to be installed in dedicated storagerooms, a separate room for each gas, on or above theuppermost continuous deck. Storage rooms are to beconstructed of steel, ventilated and provided withdirect access from the open deck. Access doors are toopen outwards, and bulkheads and decks formingboundaries between such rooms and other enclosedspaces are to be gas tight. Ventilation arrangementfor the storage rooms are to be independent of theventilation systems of other spaces and are to becapable of providing at least six air changes per hourbased on the gross volume of the space. Thetermination of ventilation inlets and exhausts is to beat least 3 m (10 ft.) from any source of vapor ignition.

Where the cylinders are to be installed in openlocations, they are to be effectively protected againstmechanical and heavy weather damage and excessiveambient temperatures. Suitable drainage of thestorage area is to be provided.

Piping systems containing flammable orcombustible liquids are not to run through the storagerooms/area. Electrical arrangements within thecylinder storage rooms or areas are to comply with4/5B7.

Cylinders are to be constructed to a recognizedstandard acceptable to the Bureau.


4/6.71.2 Piping and FittingsThe wall thickness of piping between cylinders andpressure regulators is to be in accordance with4/6.13.6. Materials for piping on the high pressureside of the regulators are to be steel for acetylene andsteel or copper for oxygen. All piping is to beseamless. Copper or copper alloys containing morethan 65% copper are not to be used in connectionwith acetylene. Where two or more cylinders areconnected to a manifold, the supply pipe betweeneach cylinder and the manifold is to be fitted with anon return valve.

Piping and fittings on the low pressure side of theregulators are to be in accordance with aboverequirements except that seamless steel pipes of atleast standard wall thickness may be used. Except forthe cylinder manifolds, acetylene is not to be piped ata pressure in excess of 1.0 bar (1.0 kgf/cm2, 15 psi).All piping on the low pressure side is to have alljoints welded. Branch lines are not to run throughunventilated spaces or accommodation spaces.

The system is to be tested in accordance with4/6.9.7.

Note: Prior to installation of oxygen and acetylene pipe lines,all piping and fittings are to be thoroughly cleaned witha suitable solution, which will not react with oxygen, toremove all grease, oil and dirt. Piping should bethoroughly blown out after assembly to remove foreignmaterials. For oxygen piping, oil-free air or oil-freenitrogen should be used. For acetylene, air or inert gasmay be used.

4/6.71.3 Pressure Relief and System ProtectiveDevices

Pressure relief devices are to be provided in the gaspiping if the maximum design pressure of the pipingsystem can be exceeded. These devices are to be setto discharge at not more than the maximum design

pressure of the piping system to a location in theweather at least 3 m (10 ft.) from sources of vaporignition or openings to spaces or tanks. The pressurerelief devices may be either a relief valve or rupturedisc.

Outlet stations are to be provided with suitableprotective devices which will:

a Prevent back flow of gas into the supplylines

b Prevent the passage of flame into the supplylines

Shutoff valves are to be fitted at each outlet.

4/6.73 Liquefied Petroleum Gases

4/6.73.1 GeneralLiquefied petroleum gas may be used for cooking andheating on all craft except passenger vessels.Liquefied petroleum gas systems are to be of thevapor withdrawal type only. Cylinders designed toadmit the liquid phase of the gas into any other part ofthe system are prohibited. All component parts of thesystem, except cylinders, appliances, and lowpressure tubing, shall be designed to withstand apressure of 34 bar (35 kgf/cm2, 500 psi) withoutrupture.

4/6.73.3 Storage CylindersCylinders for the storage of liquefied petroleum gasesare to be designed and constructed in accordance witha recognized pressure vessel standard.

4/6.73.5 Installation and TestingWhere liquefied petroleum gases are used, theinstallation and testing is to comply with a recognizedstandard.


FIGURE 4/6.1Fire Endurance TestBurner Assembly

FIGURE 4/6.2

Fire Endurance TestStand With Mounted Sample

TABLE 4/6.1Allowable Stress Values S for Steel Piping N/mm2 (kgf/mm2, psi)

Service Temperature -- Degrees C (F)Sec. 2/2 Par. & GradeNominal Composition Tensile Strength

-29C (-20F) to344C (650F) 372C (700F) 399C (750F) 427C (800F)

M = 0.8 M = 0.8 M = 0.8 M = 0.82/2.29.3-1

Elec. res. Carbon Steel310

(31.5, 45000)46.9

(4.78, 6800)46.6

(4.75, 6500)2/2.29.3-2


(33.7, 48000)70.3

(71.7, 10200)68.3

(6.96, 9900)62.8

(6.40, 9100)53.1

(5.41, 7700)Seamless Carbon Steel 330

(33.7, 48000)82.8

(8.44, 12000)80.6

(8.22, 11700)73.7

(7.52, 10700)62.1

(6.33, 9000)2/2.29.3-3


(42, 60000)88.3

(9.0, 12800)84.1

(8.58, 12200)75.8

(7.73, 11000)63.4

(6.47, 9200)Seamless Carbon Steel 415

(42, 60000)103.5

(0.55, 15000)99.2

(10.12, 14400)89.6

(9.14, 13000)74.4

(7.59, 10800)2/2.29.3-4

Carbon Steel330

(33.7, 48000)82.8

(8.44, 12000)80.7

(8.23, 11700)73.7

(7.52, 10700)62.1

(6.33, 9000)2/2.29.3-5

Carbon Steel415

(42, 60000)103.5

(10.55, 15000)99.2

(10.12, 14400)89.6

(9.14, 13000)74.4

(7.59, 10800)

Notes1 Intermediate values of S may be determined by interpolation.2 For grades of piping other than those given in Table 4/6.1, S values are not to exceed those permitted by ASME B31.1 Code for

Pressure Piping. See 4/6.13.7.3 Consideration is to be given to the possibility of graphite formation in carbon steel at temperatures above 425C (800F)


TABLE 4/6.4FIRE ENDURANCE REQUIREMENTS MATRIX

LOCATIONPIPING SYSTEMS A B C D E F G H I

FLAMMABLE LIQUIDS1 Fuel oil flash point ≤ 60C (140F) X X X X 0 0 0 NA L1

2 Fuel oil flash point > 60C (140F) X X X X 0 0 0 L1 L1

3 Lubricating oil X X X X NA NA 0 L1 L1

4 Hydraulic oil X X X X 0 0 0 L1 L1

SEA WATER (See Note 1)5 Bilge main and branches L14 L14 X X 0 0 0 NA L1

6 Fire main and water spray L1 L1 X NA NA 0 0 X L1

7 Foam system L1 L1 NA NA NA NA 0 L1 L1

8 Sprinkler system L1 L1 X NA NA 0 0 L3 L3

9 Ballast L3 L3 L3 X 0 0 0 L2 L2

10 Cooling water, essential services L3 L3 NA NA NA 0 0 NA L2

11 Non-essential systems 0 0 0 0 0 0 0 0 0

FRESH WATER12 Cooling water, essential services L3 L3 NA NA 0 0 0 L3 L3

13 Condensate return L3 L3 0 0 NA NA 0 0 0

14 Non-essential systems 0 0 0 0 0 0 0 0 0

SANITARY/DRAINS/SCUPPERS15 Deck drains (internal) L12 L12 L12 0 0 0 0 0 0

16 Sanitary drains (internal) 0 0 0 0 0 0 0 0 0

17 Scuppers and discharges (overboard) 01,5 01,5 01,5 01,5 0 0 0 01,5 0

VENTS/SOUNDING18 Water tanks/dry spaces 0 0 0 0 0 0 0 0 0

19 Oil tanks (flashpoint > 60C (140F)) NA NA NA NA NA 0 0 NA X

20 Oil tanks (flashpoint > 60C (140F)) X X X X 0 0 0 X X

MISCELLANEOUS21 Control air L13 L13 L13 L13 0 0 0 L13 L13

22 Service air (non-essential) 0 0 0 0 0 0 0 0 0

23 Brine 0 0 0 0 NA NA 0 0 0

24 Auxiliary low pressure steam (Pressure≤ 7 bar (7 kgf/cm2, 100 psi))

L2 L2 06 06 0 0 0 06 06

LocationsA Category A machinery spacesB Other machinery spacesC Ro/Ro SpacesD Other dry cargo holdsE Fuel oil tanksF Ballast water tanksG Cofferdams, void spaces, pipe tunnels and ductsH Accommodation, service and control spacesI Open decks

AbbreviationsL1 Fire endurance test in dry conditions, 60 minutes, in

accordance with 4/6.15.7L2 Fire endurance test in dry conditions, 30 minutes, in

accordance with 4/6.15.7L3 Fire endurance test in wet conditions, 30 minutes, in

accordance with 4/6.15.80 No fire endurance test requiredNA Not applicableX Metallic materials having a melting point greater than

925C (1700F).Notes1 Where non-metallic piping is used, remotely controlled valves are to be provided at the ship’s side. These valves are to be

controlled from outside the space.2 For drains serving only the space concerned, “0” may replace “L1”.3 When controlling functions are not required by statutory requirements, “0” may replace “L1”.4 For passenger craft, “X” is to replace “L1”.5 Scuppers serving open decks in positions 1 and 2, as defined in Regulation 13 of the International Convention on Load

Lines, 1966, are to be “X” throughout unless fitted at the upper end with the means of closing capable of being operatedfrom a position above the freeboard deck in order to prevent downflooding.

6 For essential services, such as fuel oil tank heating and ship’s whistle, “X” is to replace “0”.

PART 4 SECTION 7|1 Propulsion Shafting, Propellers, Waterjets and Lift Devices

PART 4 SECTION 7

Propulsion Shafting, Propellers, Waterjetsand Lift Devices

4/7.1 Propulsion Shafting and Propellers

4/7.1.1 GeneralThe construction of the propellers and propulsionshafting is to be carried out in accordance with thefollowing requirements and to the satisfaction of theSurveyor. Upon satisfactory compliance with therequirements, a notation will be made in the Recordindicating the type of propeller and the material ofwhich it is made.

4/7.1.2 Small Conventional PropellersFor planing and semi-planing craft, the propellersneed not to be designed and constructed inaccordance with these requirements provided they donot exceed 1.5m (60 in.) in diameter and are part of amanufacturer’s standard product line. In suchinstances, neither the Surveyor’s attendance for thematerial testing and inspection nor the design reviewwill be required.

4/7.1.3 Plans and Data to be SubmittedPlans and specifications are to be submitted inaccordance with 1/1.9 as indicated in the following:

a Propulsion Shafting Detailed plans togetherwith material specifications of the propulsionshafting, couplings, coupling bolts, propulsionshafting arrangement, tailshaft bearings andlubrication system, if oil-lubricated, are to besubmitted. Calculations are to be included forflexible couplings and demountable couplings, see4/4.19 and 4/7.10.7. See also 4/7.16.

b Fixed-Pitch Propellers Where the propellerblades are of conventional design, a propeller plan,giving the design data and characteristics of thematerial, as required by 4/7.23.1, is to be submitted.For skewed propellers or propeller blades of unusualdesign, a detailed stress analysis is also to besubmitted as required by 4/7.23.2 or 4/7.25.2 Forkeyless propellers see 4/7.13. For air propellersassociated with air cushion vehicles, see 4/7.38.3.

c Controllable-Pitch Propellers In addition tothe plan and data required in 4/7.1.3b for thepropeller blade; plans of the propeller hub, propellerblade flange and bolts, internal mechanisms,hydraulic piping control systems, and instrumentationand alarm system are to be submitted. Strength

calculations are to be included for the internalmechanism, see 4/7.30.

Shafting

4/7.2 Materials and Testing

4/7.2.1 MaterialThe material for shafting, couplings and couplingbolts is to be tested in the presence of the Surveyor, inaccordance with Section 2/2 or to other specificationsapproved in association with the specific design. Ingeneral, material with elongation of less than 16% in50 mm (2 in.) is not to be used for shafting,couplings, or coupling bolts, without specificapproval.

4/7.2.2 Alternative Test RequirementsMaterials for shafting, couplings, and coupling bolts,transmitting 373 kW (500 HP) or less, will beaccepted based on the manufacturer's certified milltests and hardness check witnessed by the Surveyor.Bolts manufactured to a recognized standard and usedas coupling bolts will not require material testing.

4/7.2.3 InspectionShafting and couplings are to be surface examined atthe manufacturer. Tailshafts in the finished machinecondition are to be subjected to a nondestructiveexamination such as magnetic particle, dye penetrantor other nondestructive methods and are to be free oflinear discontinuities greater than 3.2 mm (1/8 in.)except that in the following locations the shafts are tobe free of all linear discontinuities:

a Tapered Tailshafts The forward one-thirdlength of the taper, including the forward end of anykeyway and an equal length of the parallel part of theshaft immediately forward of the taper.

b Flanged Tailshafts The flange fillet area.

4/7.2.4 WeldabilitySteel used for tailshafts is to contain 0.35% or lesscarbon content, unless specially approved. See2/2.19.1b.


4/7.3 Shaft DiametersThe least diameter of propulsion shafting is to bedetermined by the following equation:

( )[ ]( )321100 cUcRHKD +=

C1 = 560 (41.95, 3.695) for single screw craft45.7 m (150 ft) in length and over andmultiple screw craft 61m (200 ft) in lengthand over

= 416.4 (31.22, 2.75) for single screw craftbelow 45.7 m (150 ft) and multiple screwcraft below 61m (200 ft)

C2 = 160 (16.3, 23180)D = required shaft diameter in mm or in. for all

shafts except those covered in 4/7.4.K = shaft design factor (see Table 4/7.1 and

4/7.2)H = power at rated speed, kW (PS, HP), [(MKS

units: 1 PS = 0.735 kW), (US units: 1 HP =0.746 kW)]

R = rpm at rated speedU = minimum specified ultimate tensile strength

of the material in N/mm2 (kgf/mm2, psi).For calculation purposes, U is not to betaken as more than the following:

= 415 N/mm2 (42.2 kgf/mm2, 60,000 psi) forcarbon, and alloy steel tailshafts fitted withsalt-water lubricated bearings and non-continuous shaft liners.

= 600 N/mm2 (61.2 kgf/mm2, 87,000 psi) forcarbon, alloy and austenitic stainless steeltailshafts fitted with oil lubricated bearingsor with continuous shaft liners or equivalent.

= 930 N/mm2 (95.0 kgf/mm2, 135,000 psi) forother shaft sections and for tailshaftsmanufactured of age-hardened martensiticstainless steels or other high strength alloymaterials.

Note In general, the minimum specified ultimate tensile strengthof steel used for propulsion shafting is to be between 400N/mm2 (40.7 kgf/mm2, 58,000 psi) and 930 N/mm2 (95.0kgf/mm2, 135,000 psi). See also 4/7.2.1.

4/7.4 Hollow ShaftsFor hollow shafts where the bore exceeds 40% of theoutside diameter, the minimum shaft diameter is notto be less than that given by the following equation.

( )[ ]D D D Do i o= −1 14

3

Do = required outside diameter in mm or in.D = solid shaft diameter required by 4/7.3, as

applicable, in mm or in.Di = actual shaft bore in mm or in.

4/7.5 Tailshaft Liners

4/7.5.1 Thickness at Bearingsa Bronze The thickness of bronze liners to be

shrink fitted to tailshafts or tube shafts of craft is notto be less in way of bearings than that given by thefollowing equation.

t = T/25 + 5.1 mm t = T/25 + 0.2 in.

t = thickness of liner in mm or in.T = required diameter of tailshaft in mm or in.

b Stainless Steel Clad The post machiningthickness of stainless steel clad liners to be fitted totailshafts or tube shafts for craft in saltwater service isnot to be less than one-half that required for bronzeliners or 6.5 mm (0.25 inches) whichever is greater.See 4/7.5.13.

c The thickness of shrink-fitted liners other thanbronze will be subject to special consideration.

4/7.5.3 Thickness Between BearingsThe thickness of a continuous bronze liner betweenbearings is to be not less than three-fourths of thethickness t determined by the foregoing equation.

4/7.5.5 Continuous Fitted LinersContinuous fitted liners are to be in one piece or, ifmade of two or more lengths, the joining of theseparate pieces is to be done by an approved methodof fusion through not less than two-thirds thethickness of the liner or by an approved rubber seal.

4/7.5.7 Fit between BearingsIf the liner does not fit the shaft tightly between thebearing portions, the space between the shaft andliner is to be filled by pressure with an insoluble non-corrosive compound.

4/7.5.9 Material and FitFitted liners are to be of a high-grade composition,bronze or other approved alloy, free from porosityand other defects, and are to prove tight underhydrostatic test of 1.0 bar (1 kgf/cm2, 15 psi). Allliners are to be carefully shrunk or forced upon theshaft by pressure and they are not to be secured bypins.

4/7.5.11 Glass Reinforced Plastic CoatingGlass reinforced plastic coatings may be fitted onpropulsion shafting when applied by an approvedprocedure to the satisfaction of the Surveyor. Suchcoatings are to consist of at least four plies of cross-woven glass tape impregnated with resin, or anequivalent process. Prior to coating, the shaft is to becleaned with a suitable solvent and grit blasted. Theshaft is to be examined prior to coating and the firstlayer is to be applied in the presence of the Surveyor.Subsequent to coating, the finished shaft is to be


subjected to a spark test or equivalent to verifyfreedom from porosity to the satisfaction of theSurveyor. In all cases where reinforced plasticcoatings are employed, effective means are to beprovided to prevent water having access to the shaft.Provisions are to be made for over-lapping andadequately bonding the coating to fitted or clad liners.The end of the liner is to be stepped and tapered asrequired to protect the end of the wrapping.

4/7.5.13 Stainless Steel CladdingStainless steel cladding of shafts is to be carried outin accordance with an approved procedure. See latestedition of the ABS Guide for Repair and Cladding ofShafts.

4/7.7 Tailshaft Bearings

4/7.7.1 Water Lubricated Bearingsa Wood Bearings (resinous, dense hardwoods)

The length of the bearing, next to and supporting thepropeller, is to be not less than four times the requiredtailshaft diameter.

b Synthetic Bearings (rubber, reinforced resins,plastic materials) The length of the bearing, next toand supporting the propeller, is to be not less thanfour times the required tailshaft diameter.

For a bearing design substantiated byexperimental tests to the satisfaction of the Bureau,consideration may be given to a bearing length of lessthan four times but not less than two times therequired tailshaft diameter.

4/7.7.3 Oil Lubricated Bearingsa White Metal Lined The length of white-metal

lined, oil lubricated propeller-end bearings fitted withan approved oil-seal gland is to be on the order of twotimes the required tailshaft diameter. The length ofthe bearing may be less provided the nominal bearingpressure is not more than 0.80 N/mm2 (0.0815kgf/mm2, 116 psi) as determined by static bearingreaction calculation taking into account shaft andpropeller weight which is deemed to be exerted solelyon the aft bearing, divided by the projected area ofthe shaft. The minimum length, however, is not to beless than 1.5 times the actual diameter.

b Synthetic Bearings (rubber, reinforced resins,plastic etc.) The length of synthetic rubber,reinforced resin or plastic oil lubricated propeller endbearings fitted with an approved oil-seal gland is tobe on order of two time the required tailshaftdiameter. The length of bearing may be less providedthe nominal bearing pressure is not more than 0.60N/mm2 (0.0611 kgf/mm2, 87 psi) as determined bystatic bearing reaction calculation taking into accountshaft and propeller weight which is deemed to beexerted solely on the aft bearing, divided by theprojected area of the shaft. The minimum length,

however, is not to be less than 1.5 times the actualdiameter. Where the material has demonstratedsatisfactory testing and operating experience,consideration may be given to increased bearingpressure.

4/7.8 Tailshaft Propeller-end DesignTailshafts are to be provided with an accurate taper fitin the propeller hub, particular attention being givento the fit at the large end of the taper.

a Keyed The key is to fit tightly in the keywayand be of sufficient size to transmit the full torque ofthe shaft, but it is not to extend into the linercounterbore on the forward side of the propeller hub.The forward end of the keyway is to be so cut in theshaft as to give a gradual rise from the bottom of thekeyway to the surface of the shaft. Ample fillets areto be provided in the corners of the keyway and, ingeneral, stress concentrations are to be reduced as faras practicable.

b Keyless Where propellers are fitted withoutkeys, detailed stress calculations and fittinginstructions are to be submitted for review. Thefactor of safety against slip at 35C (95F) is to be atleast 2.8 under the action of maximum continuousahead rating plus torque due to torsional vibrations.The astern operation is to be considered if the asterntorque exceeds the ahead torque. For oil injectionmethod of fit the coefficient of friction is to be takenno greater than 0.13 for bronze/steel propeller bosseson steel shafts. For dry method of fit using cast ironon steel shafts the coefficient of friction is to be takenno greater than 0.18. The maximum equivalentuniaxial stress in the boss at 0C (32F) is not to exceed70% of the minimum specified yield strength of thematerial at 0.2% offset (ASTM-E8). For cast iron,this stress is not to exceed 30% of the minimumspecified tensile strength.

4/7.9 Flexible CouplingsSee 4/4.19.1.

4/7.10 Solid Couplings

4/7.10.1 Fitted BoltsThe minimum diameter of fitted shaft coupling boltsis to be determined by the following equation:

( )d D U c NBUb b= +0 65 3. mm (in.)

c = 160 (16.3, 23180)db = diameter of bolts at joints in mm or in.D = required diameter of shaft as per 4/7.3.1 in

mm or in.N = number of bolts fitted in one couplingB = bolt circle diameter in mm or in.U = minimum specific tensile strength of shaft

material in N/mm2, kgf/mm2 or psi


Ub = minimum specific tensile strength of boltmaterial in N/mm2, kgf/mm2 or psi. To benot less than U. Ub is to be taken not morethan 1.7 U or 1000 N/mm2 (102 kgf/mm2,145,000 psi), whichever is less, forcalculation purposes.

Notes:1 Coupling bolts are to be accurately fitted.2 The material for coupling bolt is to be steel with an

elongation of not less than 16% in 50 mm (2 in.).3 The use of other materials will be subject to special

consideration based on submitted engineering analyses.

4/7.10.3 Non-fitted BoltsThe diameter of pre-stressed non-fitted coupling boltswill be considered upon the submittal of detailedpreloading and stress calculations and fittinginstructions. The tensile stress on the bolt due toprestressing and astern pull is not to exceed 90% ofthe minimum specified yield strength of the boltmaterial. In addition, the bearing stress on anymember such as the shaft, bolt, threads or nut is not toexceed 90% of the minimum specified yield strengthof the material for that member.

a Power Transmitted by Prestress Only Wherebolts are under pure tension, the factor of safetyagainst slip under the worst of the operatingconditions, including mean transmitted torque plusvibratory torque due to torsional loads, is to be atleast as follows:

1 Inaccessible couplings (external to thehull or not readily accessible)--2.8

2 Accessible couplings (internal to thehull)--2.0

b Power Transmitted by Combination Prestressand Shear Where the power is transmitted by acombination of fitted bolts and prestressed non-fittedbolts, the components are to meet the followingcriteria:

1 Fitted Bolts: The shear stress under themaximum torque corresponding to theworst loaded condition, is to be notmore than 50% of the minimumspecified tensile yield strength of thebolt material.

2 Non-Fitted Bolts: The factor of safetyagainst slip, under the maximum torquecorresponding to the worst loadedcondition and the specified bolt tension,is to be at least 1.6 for inaccessiblecouplings and 1.1 for accessiblecouplings.

c Dowels Used for Transmitting Power Dowelsconnecting the tail shaft flange to the controllablepitch propeller hub, utilized with non-fitted bolts totransmit power, are considered equivalent to fittedcoupling bolts and are to comply with 4/7.10.1 and, ifapplicable, 4/7.10.3b1. The dowels are to be

accurately fitted and effectively secured against axialmovement. The coupling is to be satisfactory forastern condition.

4/7.10.5 FlangesThe thickness of coupling flanges is not to be lessthan the minimum required diameter of the couplingbolts or 0.2 times D (as defined in 4/7.3), whicheveris greater. The fillet radius at the base of an integralflange is not to be less than 0.08 times the actual shaftdiameter. Consideration of a recognized shaftcoupling standard will be given to fillets of multipleradii design. In general, the surface finish for filletradii is not to be rougher than 1.6 µ meters (63 µ in.)RMS. For the fillet radius for tailshaft to propellercoupling flange, see Note 4 in Table 4/7.2.

4/7.10.7 Demountable CouplingsCouplings are to be made of steel or other approvedductile material. The strength of demountablecouplings and keys is to be equivalent to that of theshaft. Couplings are to be accurately fitted to theshaft. Where necessary, provisions for resistingthrust loading are to be provided.

Hydraulic and other shrink fit couplings will bespecially considered upon submittal of detailedpreloading and stress calculations and fittinginstructions. In general, the torsional holdingcapacity is to be at least 2.8 times the transmittedmean torque plus vibratory torque due to torsionalsfor inaccessible couplings (external to the hull or notreadily accessible) and at least 2.0 times foraccessible couplings (internal to the hull). Thepreload stress is not to exceed 70% of the minimumspecified yield strength.

4/7.16 Propulsion Shaft Alignment andVibrations

4/7.16.1 GeneralPropulsion shafting is to be aligned with the locationand spacing of the shaft bearings being such as togive acceptable bearing reactions and shaft bendingmoments and also acceptable amplitudes of vibrationfor all conditions of ship loading and operation.

The desiger or the builder is to evaluate thepropulsion shafting system taking into considerationany forces or factors which may affect the reliabilityof the propulsion shafting system including weight ofthe propeller and shafts, hydrodynamic forces actingon the propeller, number of propeller blades inrelation to diesel engine cylinders, misalignmentforces, thermal expansion, flexibility of engine andthrust bearing foundations, engine induced vibrations,gear tooth loadings, flexible couplings, effect ofpower take-off arrangements from the propulsionshafting system driving auxiliaries, etc., as applicable,


as well as any limits for vibrations and loadingsspecified by the equipment manufacturers.

4/7.16.2 Craft 61 m (200 ft) in Length and Overa Shaft Alignment Calculations The

requirements in 4/7.33.2 of the Rules for Buildingand Classing Steel Vessels are to be complied with.

b Torsional Vibrations The requirements in4/7.33.3 of the Rules for Building and Classing SteelVessels are to be complied with.

c Axial Vibrations The requirements in 4/7.33.4of the Rules for Building and Classing Steel Vesselsare to be complied with.

d Lateral (Whirling) Vibrations Therequirements in 4/7.33.5 of the Rules for Buildingand Classing Steel Vessels are to be complied with.

4/7.16.3 Craft Below 61 m (200 ft) in Lengtha Torsional Vibration For craft fitted with

unusual propulsion arrangement or without vibrationdampers, a torsional vibration analysis of thepropulsion system showing compliance with 4/7.33.3of the Rules for Building and Classing Steel Vesselsis to be submitted. This is not required for craftunder 20 m (65 ft.) in length or where the installationis essentially the same as previous designs which havebeen proven satisfactory.

Propellers

4/7.22 Materials and Testing

4/7.22.1 Propeller MaterialFor propellers required to be of an approved design,the material of the propeller is to be tested in thepresence of and inspected by a Surveyor inaccordance with the requirements of Section 2/2 or toother requirements which have been approved by theCommittee. The finished and assembled propeller isto be inspected by the Surveyor.

4/7.22.3 Stud MaterialThe material of the studs securing detachable bladesto the hub is to be of Grade 2 steel or equallysatisfactory material and is to be tested in thepresence of and inspected by the Surveyor inaccordance with the requirements of 2/2.19.4.

4/7.23 Blade Design

4/7.23.1 Blade ThicknessWhere the propeller blades are of conventionaldesign, the thickness of the blades is not to be lessthan determined by the following equations:

a Fixed-Pitch Propellers

t S KAH

C CRN

C

C

BK

Cn

s

n0 25

14. = ±

mm (in.)

A = 1.0 + (6.0/P0.70) + 4.3P0.25

B = (4300wa/N) (R/100)2 (D/20)3

C = (1 + 1.5P0.25) (Wf -B)

b Controllable-Pitch Propellers

t KAH

C CRN

C

C

BK

Cn

s

n0 35 2 6 3. .

= ±

mm (in.)

A = 1.0 + (6.0/P0.7) + 3P0.35

B = (4900wa/N) (R/100)2 (D/20)3

C = (1+0.6P0.35) (Wf - B)

c Nozzle Propellers (Wide Tip Blades)

t KAH

C CRN

C

C

BK

Cn

s

n0 35 3 5 6. .

=

±

mm (in.)

A = 1.0 + (6.0/P0.7) + 2.8P0.35

B = (4625wa/N) (R/100)2 (D/20)3

C = (1+0.6P0.35) (Wf - B)S = 1.0. for all propellers with D ≤ 6.1 m (20 ft)

= ( )D + 24 0 301. . SI, MKS units or

= ( )D + 79 99 US units for solid propellers

with D > 6.1 m (20 ft) and weighing inexcess of 20 tons. S is not to exceed 1.025.

t0.25 = required thickness at the one-quarter radiusin mm or in.

t0.35 = required thickness at the 0.35 radius in mmor in.

K1 = 337 (289, 13)K2 = 271 (232, 10.4)K3 = 288 (247, 11.1)H = power at rated speed, kW (hp, HP)

hp = metric horsepowerHP = US horsepower

R = rpm at rated speedN = number of bladesP0.25 = pitch at one-quarter radius divided by

propeller diameterP0.35 = pitch at 0.35 radius divided by propeller

diameter, corresponding to the design aheadconditions

P0.7 = pitch at seven-tenths radius divided bypropeller diameter, corresponding to thedesign ahead conditions

W = expanded width of a cylindrical section atthe 0.25 or 0.35 radius in mm or in.

a = expanded blade area divided by the disc areaD = propeller diameter, in m or ft


K = rake of propeller blade in mm/m or in./ftmultiplied by D/2 (with forward rake, useminus sign in equation; with aft rake, useplus sign)

Cs = as/WT (section area coefficient at the 0.25or 0.35 radius). Also see below.

Cn = Io/UfWT2 (section modulus coefficient at theo.25 or 0.35 radius). Also see below.

Io = moment of inertia of the expandedcylindrical section at 0.25 or 0.35 radiusabout a straight line through the center ofgravity parallel to the pitch line or to thenose-tail line in mm4 or in.4

as = area of expanded cylindrical section at the0.25 or 0.35 radius, in mm2 or in.2

Uf = maximum normal distance from the momentof inertia axis to points on the face boundary(tension side) of the section, in mm or in.

T = maximum thickness at the 0.25 or 0.35radius in mm or in. from propeller drawing

The values of Cs and Cn computed as stipulated aboveare to be indicated on the propeller drawing. If the Cn

value exceeds 0.10, the required thickness is to becomputed with Cn = 0.10.

For craft below 61m (200 ft) in length, therequired thickness may be computed with theassumed values of Cn = 0.10 and Cs = 0.69.f, w = material constants from the following table

RepresentativePropeller Materials

SI andMKS Units

US CustomaryUnits

Type (See Section 2/2) f w f w

2 Manganese bronze 2.10 8.3 68 0.303 Nickel-manganese

bronze2.13 8.0 69 0.29

4 Nickel-aluminumbronze

2.62 7.5 85 0.27

5 Mn-Ni-Al bronze 2.37 7.5 77 0.27Cast steel 2.10 8.30 68 0.30

CF-3 Austenitic stainlesssteel

2.10 7.75 68 0.28

Note The f values of materials not covered will be speciallyconsidered upon submittal of complete materialspecifications including corrosion fatigue data to 108

cycles.

4/7.23.2 Blades of Unusual DesignPropellers of unusual design or application will besubject to special consideration upon submittal ofdetailed stress calculations.

4/7.23.3 Blade-root FilletsFillets at the root of the blades are not to beconsidered in the determination of blade thickness.

4/7.23.4 Built-up BladesThe required blade section is not to be reduced inorder to provide clearance for nuts. The face of theflange is to bear on that of the hub in all cases, but the

clearance of the spigot in its counterbore or the edgeof the flange in the recess is to be kept to a minimum.

4/7.25 Skewed Propeller

4/7.25.1 Definitionsa Maximum Skew Angle Maximum skew angle

(θ) is measured from ray A passing through the tip ofblade to ray B tangent to the mid-chord line of theprojected blade outline. See Figure 4/7.1a.

b Rake Angle Rake angle (φ) for the purpose ofthis subsection is the angle measured from the planeperpendicular to shaft centerline to the tangent togenerating line at 0.6 radius. See Figure 4/7.1b.

4/7.25.2 Applicationa θ ≤≤≤≤ 25°°°° The requirements in 4/7.23.1 are

applicable where the maximum skew angle is 25degrees or less.

b 25°°°° < θ ≤≤≤≤ 50°°°° The requirements in 4/7.25.3may be used for fixed pitch propellers of ABS Type 4material having skew angle over 25 degrees but notexceeding 50 degrees. For other material/typepropellers, calculations as required in 4/7.25.2c are tobe submitted.

c θ > 50°°°° Propellers with the maximum skewangle exceeding 50 degrees will be subject to specialconsideration upon submittal of detailed stresscalculations.

The maximum stress occurring during steady ortransient astern operations is not to exceed seventyper cent of the minimum specified yield strength ofthe propeller material.

4/7.25.3 Propellers Over 25 up to 50°°°° Skew AngleThis paragraph applies to fixed pitch propellers ofABS Type 4 material having a maximum skew angleover 25 degrees but not exceeding 50 degrees.

a Blade Thickness at 0.25 Radius Themaximum thickness at 0.25 radius is not to be lessthan the thickness required in 4/7.23.1a multiplied bythe factor m as given below:

( )m = + −1 0 0065 25. θ

b Blade Thickness at 0.6 Radius The maximumthickness at 0.6 radius is to be not less than thatobtained from the following equation:

( )( ) ( ) ( )[ ]t K C C C HD RP Y0 6 0 9 0 9 0 6 0 6

0 51 1 2. . . . .

.= + + Γ

t0.6 = required thickness at the 0.6 radius in mm(in.)

K3 = 12.6 (6.58, 1.19)C0.9 = expanding chord length at the 0.9 radius

divided by propeller diameter


C0.6 = expanded chord length at the 0.6 radiusdivided by propeller diameter

H, D, R = as defined in 4/7.23.1Γ = [1+(θ - 25)/ θ][φ2 + 0.16φθP0.9 + 100]θ = skew angle in degrees (see 4/7.25.1a and

Figure 4/7.1a.)φ = rake angle in degrees (see 4/7.25.1b and

Figure 4/7.1b), positive for rake aftP0.6 = pitch at the 0.6 radius divided by propeller

diameterP0.9 = pitch at the 0.9 radius divided by propeller

diameterY = minimum specified yield strength of ABS

Type 4 propeller material in N/mm2 (kgf/m2,psi)

c Blade Thickness Between 0.6 and 0.9 Radius1 Maximum Thickness The maximum

thickness between 0.6 and 0.9 radius isnot to be less than that obtained fromthe following equation.

( )( )t D x t Dx = + − −33 2 5 1 330 6. . .. mm

( )( )t D x t Dx = + − −0 04 2 5 1 0 040 6. . .. in.

tx = required maximum blade thickness at radiusx

t0.6 = blade thickness at 0.6 radius as required by4/7.25.3b

x = ratio of the radius under consideration toD/2, 0.6 < x ≤ 0.9

2 Trailing Edge Thickness at 0.9 RadiusThe edge thickness measured at 5% ofchord length from the trailing edge is tobe not less than 30% of the maximumblade thickness required by 1 above atthat radius.

4/7.28 Studs

4/7.28.1 Stud AreaThe sectional area of the studs at the bottom of thethread is to be determined by the following equation:

s = 0.056kWt2f / rn mm2

s = 0.0018kWt2f / rn in.2

k = C/(U+C1) material correction factorC = 621 (63.3, 90,000)C1 = 207 (21.1, 30,000)U = ultimate tensile strength of the stud material

kg/mm2 (psi)s = area of one stud at bottom of thread in mm2

or in2.n = number of studs on driving side of blade

r = radius of pitch circle of the studs in mm orin.

W, f and t are defined under 4/7.23.1.

4/7.28.3 Fit of Studs and NutsStuds are to be fitted tightly into the hub and providedwith effective means for locking. The nuts are also tohave a tight-fitting thread and be secured by stopscrews or other effective locking devices.

4/7.30 Blade Flange and Mechanisms

The strength of the propeller blade flange and internalmechanisms of controllable-pitch propellers subjectedto the forces from propulsion torque is to be at least1.5 times that of the blade at design pitch conditions.

4/7.32 Controllable Pitch Propeller System

4/7.32.1 Piping Arrangementa General At least two hydraulic power pump

units are to be provided. Piping for the hydraulicsystem is to be arranged so that transfer betweenpump units can be readily effected. The arrangementof piping is to be such that a single failure in one partof the piping or pump unit will not impair theintegrity of the remaining parts of the system. Formultiple screw craft with controllable pitch propellersystems that are completely independent of each othersuch that a failure in one system will not affect theother systems, the above single failure criteria neednot be applied provided the ability to control andpropel the craft with the remaining propeller(s) can bedemonstrated to the satisfaction of the Surveyor.Where necessary, arrangements for bleeding air fromthe hydraulic system are to be provided.

b Piping Piping is to meet the requirements of4/6.67.

c Testing After installation in the craft, thecomplete piping system is to be subjected tohydrostatic test equal to 1.5 times the design pressure,including a check of the relief valve operation. Thesetests are to be performed in the presence of theSurveyor.

4/7.32.3 Control of PitchIndependent manual control of pitch is to be providedat or near the oil distribution box. For craft fittedwith shipboard automatic and remote control systems,refer to Section 4/11.

4/7.32.5 Instrumentation and AlarmsThe following instruments and alarms are to beprovided.

a Pitch Indicators Each station capable ofcontrolling the propeller pitch is to be fitted with apitch indicator. In addition, a pitch indicator is to be


fitted on the navigation bridge for craft 500 gross tonsand above.

b Low Oil Pressure Visual and audible alarmsare to be provided in the engine room control stationto indicate low hydraulic oil pressure.

c High Oil Pressure Visual and audible alarmsare to be provided in the engine room control stationto indicate high hydraulic oil pressure. The alarm isto be set below relief valve pressure.

d High Temperature Visual and audible alarmsare to be provided in the engine room control stationto indicate high hydraulic oil temperature.

4/7.32.7 Electrical ComponentsElectrical components are to meet the applicablerequirements of Section 4/5.

4/7.34 Protection Against Corrosion

4/7.34.1 Propeller Aft EndThe exposed steel of the shaft is to be protected fromthe action of the water by filling all spaces betweencap, hub and shaft with a suitable material. Thepropeller is to be fitted with a fairwater cap, acornnut, or other suitable after end sealing arrangementswhich prevents sea water from having contact withthe shaft taper area. See Figure 4/7.1 for typicalsealing arrangement.

4/7.34.3 Propeller Forward EndThe propeller assembly is to be sealed at the forwardend with a well-fitted soft-rubber packing ring. Whenthe rubber ring is fitted in an external gland, the hubcounterbore is to be filled with suitable material, andclearances between shaft liner and hub counterboreare to be kept to a minimum. When the rubber ring isfitted internally, ample clearance is to be providedbetween liner and hub and the ring is to besufficiently oversize to squeeze into the clearancespace when the propeller is driven up on the shaft;and, where necessary, a filler piece is to be fitted inthe propeller hub keyway to provide a flat unbrokenseating for the ring.

The recess formed at the small end of the taper bythe overhanging propeller hub is to be packed with arust preventive compound before the propeller nut isput on.

4/7.34.5 Non-Corrosive, Non-Pitting AlloysThe sealing arrangements above are not requiredwhere the tailshaft is fabricated of corrosion-resistant,pitting-resistant alloy unless required by themanufacturer.

Waterjets

4/7.36 Waterjets

4/7.36.1 GeneralFull details are to be submitted for the forcetransmitting parts of waterjet units including materialspecifications. For craft over 24 m (79 ft.) the unitsare to be manufactured under Surveys. Millcertificates are to be provided for the components ofthe steering section. The material tests for theimpellers shafts and couplings are to be witnessed bythe Surveyor. Hydraulic cylinders are to bemanufactured and inspected in accordance with therequirements of 4/6.69. The use of galvanicallydissimilar metallic materials is to be considered in thewaterjet design.

4/7.36.3 DesignDesign basis stress calculations for the impellers,shafting, steering mechanism, and reversingmechanism are to be submitted to substantiate thesuitability and strength of the components for theintended service. For the purpose of design reviewthe stress calculations are to be cover the "worst case"condition for each component. The factor of safetyfor the above components is not to be less than 2.0when determined by the following equation:

1

FS

S

U

S

Es a= +

nor less than 4.0 when determined by the followingequation:

FSU

Ss

=

FS = factor of safetySs = steady stress of low cycle alternating stressSa = alternating stressU = ultimate tensile strength of materialE = corrected fatigue strength of material (based

on 108 cycles)

4/7.36.5 HousingsCalculations or test results to substantiate thesuitability and strength of the pressure and suctionhousing are to be submitted for review. Thecondition with the inlet of the suction blocked is alsoto be considered. A factor of safety of not less than 4based on the ultimate tensile strength of the material(or 2 based on the yield strength) is to be maintainedat each point in the housing. Housing are to behydrostatically tested to 1.5 times the maximumworking pressure or to 3.4 bar (3.5 kgf/cm2, 50 psi)whichever is greater.


4/7.36.7 Reversing MechanismsAstern thrust is to be provided in sufficient amountsto secure proper control of the craft in all normalcircumstances. The reversing mechanism is toprovide for reversing at full power.

4/7.36.9 Impeller BearingsAntifriction bearings are to have a B10 life of at least80,000 hours.

Propulsion and Lift Devices for AirCushion Vessels

4/7.38 Propulsion and lift devices

4/7.38.1 GeneralPropulsion arrangements and lift arrangements maybe provided by separate devices, or be integrated intoa single propulsion and lift device. Propulsiondevices are those which directly provide thepropulsive thrust and include machinery items andany associated air propellers, ducts, vanes, scoopsand nozzles, the primary function of which is tocontribute to the propulsive thrust. The lift devicesare those items of machinery which directly raise thepressure of the air and move it for the primarypurpose of providing lifting force for an air-cushionvehicle.

4/7.38.3 DesignDesign basis stress calculations for the propulsionand lift devices are to be submitted to substantiate thesuitability and strength of the components for theintended service and compliance with a recognizedstandard or code of practice.

4/7.38.5 EnvironmentThe design of propulsion and lift devices is to paydue regard to the effects of allowable corrosion,electrolytic action between different metals, erosionor cavitation which may result from operation inenvironments in which they are subjected to spray,debris, salt, sand, icing, etc.

4/7.38.7 ArrangementAppropriate arrangements are to be made to ensurethat:

a Ingestion of debris or foreign matter isminimized:

b The possibility of injury to personnel fromshafting or rotating parts is minimized; and

c Where necessary, inspection and removal ofdebris can be carried out safely in service.


Figure 4/7.1Propeller Hub Details

1 Liberal Fillet2 Chamfer corners of key3 Break sharp corners4 Fill with suitable sealing

material5 Locking device6 Threaded holes for jack bolts

7 Soft rubber ring8 Fill and vent holes. One to be

centered on kewyway9 See 4/7.23.410 See typical hub seals11 Face (tension side)12 Back (compression side)

FIGURE 4/7.1aMaximum Skew Angle

FIGURE 4/7.1bRake Angle at the 0.6 Radius,Positive Aft

The rake angle φ, measured at0.6 radius, is formed betweenline D which is tangent to thegenerating line, and the line Cwhich is perpendicular to thepropeller shaft centerline


TABLE 4/7.1Shaft Design Factor K for Lineshafts, Thrust Shafts, and Oil Distribution Shafts

Design Features1

PropulsionType

Integralflange

Shrink fitcoupling Keyways2

Radialholes,

transverseholes3

Longitudinalslots4

On bothsides ofthrustcollars

In way ofaxial

bearingsused asthrust

bearings

Straightsections

Turbine Drives

Electric Drives

Diesel Drivesthrough slipcouplings(electric orhydraulic)

0.95 0.95 1.045 1.045 1.14 1.045 1.045 0.95

All Other DieselDrives

1.0 1.0 1.1 1.1 1.2 1.1 1.1 1.0

Notes1 Geometric features other that those listed will be specially considered2 After a length of not less than 0.2 x D from the end of the keyway, the shaft diameter may be reduced to the diameter calculated for straight

sections.Fillet radii in the transverse section of the bottom of the keyway are to be not less than 0.0125 x D

3 Diameter of bore not more than 0.3 x D4 Length of the slot not more than 1.4 x D, width of the slot not more than 0.2 x D, whereby D is calculated with k = 1.0

TABLE 4/7.2Shaft Design Factor K for Tail Shafts and Stern Tube ShaftsTail shafts may be reduced to stern tube shaft diameter forward of the bearing supporting the propeller. The inboard end of tailshafts or tubeshafts is to be designed the same as line shafts, with shaft design factors in accordance with Table 4/7.1.

Propeller attachment method1

Propulsion TypeStern tube

configuration Keyed2Keyless attachment

by shrink fit3Flanged4 Stern Tube Shafts5,6

All Oil lubricatedbearings

1.26 1.22 1.22 1.15

All Water lubricatedbearings with

continuous shaftliners or equivalent

1.26 1.22 1.22 1.15

All Water lubricatedbearings with

noncontinuous shaftliners

1.29 1.25 1.25 1.18

Notes1 Other attachments are subject to special consideration.2 Fillet radii in the transverse section at the bottom of the keyway are not to be less than 0.0125D.3 See also 4/7.8.4 The fillet radius in the base of the flange, for the tail shaft flange supporting the propeller, is to be at least 0.125D. Special consideration

will be given to fillets of multiple radii design. The fillet radius is to be accessible for non-destructive examination during tail shaft surveys.See 2/3.13.3. For other fillet radii, see 4/7.10.5.

5 K factor applies to shafting between the forward edge of the propeller-end bearing and the inboard stern tube seal.6 Where keyed couplings are fitted on stern tube shaft, the shaft diameters are to be increased by 10% in way of the coupling. See Note 2 of

Table 4/7.1.

PART 4 SECTION 8|1 Steering

PART 4 SECTION 8

Steering

4/8.1 General

4/8.1.1 ApplicationTheses requirements apply to craft with a traditionaltype steering gear which have a rule required upperrudder stock diameter less than 230 mm (9 in.).Where the rule required upper rudder stock diameteris 230 mm (9 in.) or above, the Rules for Buildingand Classing Steel Vessels are to be applied.

Where a rudder is not fitted and steering isachieved by change of setting of the propulsion units,such as the use of cycloidal, azimuthing or similartype propulsion systems, Sections 2 and 4 of the ABS“Guide for Thrusters and Dynamic PositioningSystems” are to be applied.

Where a rudder is not fitted and steering isachieved by waterjet nozzles, the material and designrequirements of 4/7.36 are applicable. Where thedirectional control system is power operated, thecontrol and power systems are to meet the intent of4/8.4 and 4/8.6.

4/8.1.2 Definitionsa Main Steering Gear Main steering gear is the

machinery, rudder actuators, power units, ancillaryequipment and the means of applying torque to therudder stock (e.g. tiller or quadrant) necessary foreffecting movement of the rudder for the purpose ofsteering the ship.

b Auxiliary Steering Gear Auxiliary steeringgear is the equipment other than any part of the mainsteering gear necessary to steer the ship in the eventof failure of the main steering gear but not includingthe tiller, quadrant or components serving the samepurpose.

c Control System Control system is theequipment by which orders are transmitted from thenavigation bridge to the power units. Control systemscomprise transmitters, receivers, hydraulic controlpumps and their associated motors, motor controllers,piping and cables. For the purpose of the Rules,steering wheels or steering levers are not consideredto be part of the control system.

d Power Units A steering gear power unit is:1 in the case of electric steering gear, an

electric motor and its associatedelectrical equipment,

2 in the case of electro-hydraulic steeringgear, an electric motor and itsassociated electrical equipment andconnected pump(s), and

3 in the case of other hydraulic steeringgear, a driving engine and connectedpump(s).

e Power Actuating System Power actuatingsystem is the hydraulic equipment provided forsupplying power to turn the rudder stock, comprisinga power unit or units, together with the associatedpipes and fittings, and a rudder actuator. The poweractuating systems may share common mechanicalcomponents, i.e. tiller, quadrant, rudder stock orcomponents serving the same purpose.

f Rudder Actuator Rudder actuator is thecomponent which directly converts hydraulic pressureinto mechanical action to move the rudder.

g Maximum Working Pressure Maximumworking pressure is the expected pressure in thesystem when the steering gear is operated to complywith 4/8.1.5.

4/8.1.3 Plans and DataPlans and data of the steering gear system to besubmitted are as follows:

Plansa General arrangements of the main and

auxiliary steering gears, and of the steeringgear compartment.

b Assembly of upper rudder stock, tiller, tierod, rudder actuators, etc. as applicable.

c Construction details of all torque-transmitting components of steering gear,such as tiller, tiller pin, tiller/rudder stockinterference fit mechanism, tie rod, rudderactuator, etc, including bill of materials,welding procedures, non-destructive testing,as applicable.

d Schematic hydraulic piping diagram,incorporating hydraulic logic diagram, andincluding bill of materials, typical pipe topipe joint details, pipe to valve joint details,pipe to equipment joint details, pressurerating of valves and pipe fittings, andpressure relief valve settings.


e Steering gear control system incorporatingschematic electrical control logic diagram,instrumentation, alarm devices, etc, andincluding bill of materials.

f Electrical power supply to power units andto steering gear control, including schematicdiagram of motor controllers, feeder cables,feeder cable electrical protection.

Datag Rated torque of main steering gear.h Calculations of torque-transmitting

components such as tiller, tie rod, rudderactuator, etc.

4/8.1.4 Power OperationThe main steering gear is to be power operated, byone or more power units, if the rule required upperrudder stock diameter is 120 mm (4.7 in.) or greater.

Notwithstanding the above, the performancerequirements stated in 4/8.1.5 and 4/8.1.6 are to beused to determine if it is necessary for the main andauxiliary steering gears to be power operated.

4/8.1.5 Main Steering Gear CapabilityThe main steering gear is to be capable of putting therudder from 35o on one side to 35o on the other sidewith the craft running ahead at maximum continuousshaft rpm and at the design draft; and under the sameconditions, the travel time from 35o on either side to30o on the other side is not to be more than 28seconds. For controllable pitch propellers, thepropeller pitch is to be at the maximum design pitchapproved for the above maximum continuous aheadrated RPM.

4/8.1.6 Auxiliary Steering GearThe auxiliary steering gear is to be capable of puttingthe rudder from 15o on one side to 15o on the otherside in not more than 60 seconds with the craftrunning ahead at half speed, or seven knots,whichever is greater.

The auxiliary steering gear is to be so arrangedthat the failure of the main steering gear will notrender it inoperative. Likewise, failure of auxiliarysteering gear is not to affect the main steering gear.

An auxiliary steering gear is not required underthe following conditions.

a When the main steering gear comprises two ormore power units, and is so arranged that after asingle failure in its piping system or in one of thepower units the defect can be isolated so that thesteering capability can be maintained or regained; andprovided that

1 for passenger craft, the main steeringgear is capable of operating the rudderas required in 4/8.1.5 while any one ofthe power units is out of operation; and

2 for cargo craft, the main steering gear isto be capable of operating the rudder asrequired by 4/8.1.5 while all the powerunits are in operation.

b When the main steering gear is non-poweroperated such as an orbitrol system or consists solelyof mechanical components such as sheaves, blocks,wires, chains, etc.

4/8.1.7 Steering Gear Compartment UnitLocation

The main and the auxiliary steering gears are to beprotected from weather. The power units may belocated either within or outside the compartmentcontaining the rudder actuators. In the event of lossof hydraulic fluid and of the need to restore theoperation of the main or the auxiliary steering gear,the steering gear compartment is to be provided withhandrails and gratings, or other non-slip surfaces, toensure suitable working condition.

In the event of control system failure, or the needto operate the main or the auxiliary steering gear fromwithin the steering gear compartment or frompositions other than the navigating bridge, craft of500 gross tons and above are to be provided with ameans to indicate the position of the rudder at thesepositions where emergency steering is to beconducted.

4/8.2 Materials

4/8.2.1 GeneralAll steering gear components transmitting a force tothe rudder and pressure retaining components ofhydraulic rudder actuator are to be of steel or otherapproved ductile material. The use of gray cast ironor other material having an elongation less than 12%in 50 mm (2 in.) is not acceptable.

4/8.2.2 Material TestingExcept as modified below, materials for the parts andcomponents mentioned in 4/8.2.1 are to be tested inthe presence of the Surveyor in accordance with therequirements of 2/2.

Material tests for steering gear coupling bolts andtorque transmitting keys need not be witnessed by theSurveyor.

Material tests for commercially supplied tie-rodnuts need not be witnessed by the Surveyor providedthe nuts are in compliance with the approved steeringgear drawings and are appropriately marked andidentified in accordance with a recognized industrystandard. Mill test reports for the tie-rod nuts are tobe made available to the Surveyor upon request. Forall non-standard tie-rod nuts, material testing isrequired to be performed in the presence of theSurveyor.


Material tests for forged, welded or seamless steelparts (including the internal components) and all non-ferrous parts of rudder actuators that are not morethan 152.4 mm (6 in.) in internal diameter need not becarried out in the presence of the Surveyor. Suchparts are to comply with the requirements of 2/2 orsuch other appropriate material specifications as maybe approved in connection with a particular design,and will be accepted on the basis of presentation ofmill certificates to the Surveyor for verification.

4/8.3 Design

4/8.3.1 Power Gear StopsPower operated steering gears are to be provided witharrangements for stopping the steering gear before therudder stops are reached. These arrangements are tobe synchronized with the rudder stock or position ofthe steering gear itself rather than with the steering-gear control system.

4/8.3.2 Mechanical ComponentsAll steering gears parts transmitting force to or fromthe rudder, such as tillers, quadrants, rams, pins, tierods and keys are to be proportioned to have strengthequivalent to that of the rule required upper rudderstock diameter.

4/8.3.3 TillerTillers are to comply with the following requirements.All terms in the formulae are to have consistent units.

1 Depth of tiller hub is not to be less than rulerequired upper rudder stock diameter.

2 Thickness of tiller hub is not to be less thanone third of the rule required upper rudderstock diameter.

3 Notwithstanding (2) above, polar sectionmodulus of the tiller hub is not to be lessthan:

0196 3. SU

UR

T

whereS = rule required upper rudder stock diameterUR = ultimate tensile strength of the rudder stockUT = ultimate tensile strength of the tiller

4 The shear area of the tiller key is not to beless than:

0196 3. S

r

U

UR

K

⋅

wherer = mean radius of the rudder stock in way of

the keyUK = ultimate tensile strength of the key

Other symbols are defined above.

5 Bearing stress of the tiller and rudder stockkeyways are not to be less than 0.9 times thematerial yield stress.

6 If tiller is shrink fitted to the rudder stock,preloading and stress calculations and fittinginstructions are to be submitted. Thecalculated torsional holding capacity is to beat least 2.0 times the transmitted torquebased on the steering gear relief valvesetting. Preload stress is not to exceed 70%of the minimum yield strength.

7 Section modulus of tiller arm at any pointwithin it length is not to be less than:

0167 32 1

2

. ( )S L L

L

U

UR

T

−⋅

whereL2 = distance from the point of application of the

force on the tiller to the center of rudderstock

L1 = distance between the section of the tiller armunder consideration and the center of therudder stock

Other symbols are defined above

8 Where tiller is of welded construction, welddesign and weld sizes are to be proportionedsuch that they are commensurate with thestrength of the tiller.

4/8.3.4 PinShear area of tiller pin is not to be less than:

0196 3

2

. S

L

U

UR

P

⋅

whereUP = ultimate tensile strength of the pinOther symbols are defined above.

4/8.3.5 Tie Rod (Jockey Bar)The buckling strength of the tie rod is not to be lessthan:

0113 3

2

. S U

LR

Symbols are defined above.

4/8.3.6 Rudder Actuatorsa General Rudder actuators are to meet the

requirements in 4/8.2 for materials and material testsand 2/3B.1 for welding. They are also to meet therequirements for pressure vessels in the Rules forBuilding and Classing Steel Vessels, specifically


4/2.5.1 (for malleable cast iron, use y = 0.5), 4/2.9and 4/2.11 (in association with S as defined below)for design and 4/2.39 for hydrostatic tests. Themaximum allowable stress S is not to exceed thelower of the following:

U

A or

Y

B

whereU = minimum specified tensile strength of

material at room temperatureY = minimum specified yield point or yield

strengthA & B = factors as given in the following table.

Factor Rolled orForgedSteel

CastSteel

NodularCast Iron

A 3.5 4 5B 1.7 2 3

b Oil Seals Oil seals between non-moving partsform the external boundary are to be of the pressureseal type. Oil seals between moving parts formingthe external pressure boundary are to be fitted induplicate so that the failure of one seal does notrender the actuator inoperative. Alternative sealarrangement may be acceptable provided equivalentprotection against leakage can be ensured.

4/8.3.7 Mechanical Steering GearWhere mechanical steering system are permitted, thefollowing are applicable.

a Steering Chains and Wire Ropes Steeringchains and wire rope are to be tested as required by2/1.11 and 2/1.13 respectively.

b Sheaves Sheaves are to be of ample size andso placed as to provide a fair lead to the quadrant andavoid acute angles. Parts subjected to shock are notto be of cast iron. Guards are to be placed aroundthe sheaves to protect against injury. For sheavesintended to use with ropes, the radius of the groovesis to be equal to that of the rope plus 0.8 mm(1/32in.), and the sheave diameter is to be determinedon the basis of wire rope flexibility. For 6 X 37 wirerope, the sheave diameter are to be not less than 18times that of the rope. For wire ropes of lesserflexibility, the sheave diameter is to be increasedaccordingly. Sheave diameters for chain are to be notless than 30 times the chain diameter.

c Buffers Steering gears other than hydraulictype are to be designed with suitable bufferarrangement to relieve the gear from shocks to therudder.

4/8.4 Hydraulic System

4/8.4.1 Pipes, Valves & FittingsPipes, valves and fittings are to meet the requirementsof 4/6.67, as applicable. The design pressure ofpiping components subject to internal hydraulicpressure is to be at least 1.25 times the maximumworking pressure of the system. Arrangements forbleeding air from hydraulic system are to beprovided, where necessary.

4/8.4.2 Relief ValvesRelief valves are to be provided for the protection ofthe hydraulic system. Each relief valve is to becapable of relieving not less than the full flow of allthe pumps which can discharge through it increasedby 10%. With this flow condition, the maximumpressure rise is not to exceed 10% of the relief valvesetting. In this regard, consideration is to be given tothe extreme expected ambient conditions in respect tooil viscosity. The relief valve setting is to be at least1.25 times the maximum working pressure but is notto exceed the design pressure.

4/8.4.3 FiltrationA means is to be provided to maintain cleanliness ofthe hydraulic fluid.

4/8.4.4 Single FailureWhere multiple power units are provided and anauxiliary steering gear is not fitted, the steering gearhydraulic system is to be designed so that after asingle failure in its piping system, one of the powerunits, or mechanical connection to the power units,the defect can be isolated so that the integrity of theremaining part of the system will not be impaired andthe steering capability can be maintained or regained.For this purpose, piping system associated with eachpower unit is to be independent of that of the otherunits as far as practicable and connections are madeonly where necessary. Isolation valves are to befitted, as necessary, to allow any single failure in thepiping system be isolated and the steering gear beoperated with the remaining intact part of the system.Isolation valves are to be fitted at the pipeconnections to rudder actuators. Where non-duplicated rudder actuator is employed, the isolationvalves are to be mounted directly on the actuator.Piping systems are to be so arranged that transferbetween power units can be readily effected.

4/8.4.5 Reservoir and Storage TankAll open-loop hydraulic systems are to be providedwith an oil reservoir of suitable capacity. In addition,for craft of 500 gross tons and above, a fixed storagetank having sufficient capacity to recharge at leastone hydraulic power system including the reservoir isto be provided. The tank is to be permanently


connected by piping in such a manner that the systemcan be readily recharged from a position within thesteering gear compartment.

4/8.5 Power UnitsIf the rule required upper rudder stock diameter is120 mm (4.7 in.) or greater, power units are to betested and certified in accordance with the followingrequirements. If the rule required upper rudder stockdiameter is less than 120 mm (4.7 in.), and if the craftis 500 gross tons or greater, power units are to betested and certified in accordance with 4/8.5.2 only.For craft less than 500 gross tons, power units may beaccepted based on manufacturer’s guarantee forsuitability for the intended purpose and subject tosatisfactory functional tests after installation.

4/8.5.1 Prototype TestA prototype of each new design power unit pump isto be shop tested for a duration of not less than 100hours. The testing is to be carried out in accordancewith an approved agenda and is to include thefollowing as a minimum.

a The pump and stroke control (or directionalcontrol valve) is to be operated continuously from fullflow and relief valve pressure in one directionthrough idle to full flow and relief valve pressure inthe opposite direction.

b Pump suction conditions are to simulatelowest anticipated suction head. The power unit is tobe checked for abnormal heating, excessive vibration,or other irregularities. Following the test, the powerunit pump is to be disassembled and inspected in thepresence of a Surveyor.

4/8.5.2 Production Unit TestEach power unit pump is to meet the hydrostatic andcapacity tests in accordance with 4/6.8, as applicable.

4/8.6 Steering Gear Control System

4/8.6.1 Locations of Controla The main steering gear is to be provided with

control both from the navigating bridge and fromwithin the steering compartment. However, if thepower unit is located in a space other than thesteering compartment, the control is to be provided inthat space instead of the steering compartment. Forpurpose of controlling from the steering gearcompartment (or the space containing the powerunit), a means is to be provided in the steeringcompartment (or the space containing the power unit)to disconnect any control system from the navigatingbridge.

b The auxiliary steering gear is to be operablefrom a space in which the operation of the auxiliarysteering gear can be effectively carried out, or fromwithin the steering compartment. However, if poweroperated, it is to be provided with control from thenavigation bridge also.

c Where duplicate (or more) power units areprovided and an auxiliary steering gear is not fitted,two independent systems of control are to beprovided. Each of these systems is to meet therequirements of the control system of the mainsteering gear (See 4/8.6.1a). Where the controlsystem consists of a hydraulic telemotor, a secondindependent system need not be fitted.

d If steering gear is operated by manual meansonly, such as by means of a steering wheel through amechanical or a non-power operated hydraulicsystem, only the requirements of 4/8.6.4 and 4/8.6.5aare applicable.

4/8.6.2 Control System Segregationa Control systems of the main and the auxiliary

steering gears are to be independent of each other inall respects. The control wires are to be separated asfar as practicable throughout their length. Wherefound necessary, the wiring of the two systems mayshare the same terminal box, provided a safety barrieris fitted in the box to segregate the wiring.

b If the main steering gear consists of duplicated(or more) power units and an auxiliary steering is notfitted, the two independent means of control are tocomply with the segregation requirement of 4/8.6.2a.However, this does not require duplication of steeringlever or other steering apparatus on the navigatingbridge.

c If the main steering gear consists of a singlepower unit and the auxiliary steering gear is notpower operated, only one control system for the mainsteering gear need be provided.

4/8.6.3 Control System Power SupplyElectrical power for steering gear control system is tobe derived from the motor controller of the powerunit it is controlling, or from the main switchboard ata point adjacent to the supply to the power unit.

4/8.6.4 CommunicationA means of communication is to be provided betweenthe navigating bridge and all other locations wheresteering can be effected, such as the steering gearcompartment, the space where the power units arelocated and the space where auxiliary steering gear isto be operated, as applicable.

4/8.6.5 Instrumentation and AlarmsThe following instruments and alarms are to beprovided. The audible and visual alarms are to haveprovisions for testing.

a Rudder Position Indicator The angularposition of the rudder is to be indicated on thenavigating bridge and all other locations wheresteering can be effected, such as the steering gearcompartment, the space where the power units arelocated and the space where auxiliary steering gear is


to be operated, as applicable. The rudder angleindication is to be independent of the steering gearcontrol system.

b Autopilot Where autopilot is fitted, a visualand audible alarm is to be provided on the navigatingbridge to indicate its failure.

Where power unit is provided and steering iscontrolled from navigating bridge, the following areapplicable:

c Motor Alarm A visual and audible alarm is tobe given on the navigating bridge and the engineroom control station to indicate an overload conditionof the steering gear power unit motor. Where threephase electrical power is used a visual audible alarmis to be installed which indicates failure of any one ofthe supply phases. The operation of these alarms isnot to interrupt the circuit.

d Motor Running Indicators Indicators forrunning indication of motors are to be installed on thenavigating bridge and the engine room controlstation.

e Power Failure A visual and audible alarm isto be given on the navigating bridge and engine roomcontrol station to indicate a power failure to any oneof the steering gear power units.

f Control Power Failure A visual and audiblealarm is to be given on the navigating bridge andengine room control station to indicate an electricalpower failure in any steering gear control circuit orremote control circuit.

In addition, hydraulic power operated steering gear isto be provided with the following:

g Low Oil-level Alarm A visual and audiblealarm is to be given on the navigating bridge andengine room control station to indicate a low oil levelin any power unit reservoir.

h Hydraulic Lock Where the arrangement issuch that a single failure may cause hydraulic lockand loss of steering, an audible and visual alarmwhich identifies the failed system or component is tobe provided on the navigating bridge. The alarm is tobe activated upon steering gear failure if:

- position of the variable displacement pumpcontrol system does not correspond to thegiven order, or

- incorrect position of 3-way full flow valve orsimilar in constant delivery pump system isdetected.

4/8.7 Electrical Power SupplyElectrical power circuits are to meet the requirementsof 4/5A6 and 4/5A3.3.5.

4/8.8 Testing and Trials

4/8.8.1 Testing of Piping SystemThe following tests are to be performed in thepresence of the Surveyor.

a Shop Tests After fabrication, each componentof the steering gear piping system, including thepower units, hydraulic cylinders and piping is to behydrostatically tested at the plant of manufacture to1.5 times the relief valve setting, except that forsteering gear cylinders of nodular iron, the testpressure is to be at least 2 times the relief valvesetting.

b Installation Tests After installation in thecraft, the complete piping system, including powerunits, hydraulic cylinders and piping is to besubjected to a hydrostatic test equal to 1.1 times therelief valve setting, including a check of the reliefvalve operation.

4/8.8.2 TrialsThe steering gear is to be tried out on the trial trip inorder to demonstrate to the Surveyor’s satisfactionthat the requirements of the Rules have been met.The trial is to include the operation of the following:

a The main steering gear, includingdemonstration of the performance requirements of4/8.1.5 or with the rudder fully submerged. Wherefull rudder submergence cannot be obtained in ballastconditions, special consideration may be given tospecified trials with less than full ruddersubmergence.

Trials are to be carried out with the craft runningahead at maximum continuous rated shaft RPM. Forcontrollable pitch propellers, the propeller pitch is tobe at the maximum design pitch approved for theabove maximum continuous ahead RPM.

b The auxiliary steering gear, if required,including demonstration to the performancerequirements of 4/8.1.6 and transfer between mainand auxiliary steering gear.

c The power units, including transfer betweenpower units.

d The emergency power supply required by4/5A3.3.5.

e The steering gear controls, including transferof control, and local control.

fThe means of communications as required by4/8.6.4

g The alarms and indicators required by4/8.6.5 (test may be done at dockside).

h The storage and recharging system containedin 4/8.4.5 (test may be done at dockside).

i The isolating of one power actuating system,and checking for regaining steering capability arerequired by 4/8.4.4 if applicable (test may be done atdockside).

j Where steering gear is designed to avoidhydraulic locking, this feature is to be demonstrated.

PART 4 SECTION 9|1 Fire Extinguishing Systems

PART 4 SECTION 9

Fire Extinguishing Systems

4/9.1 General

4/9.1.1 Classification RequirementsThe following are the minimum classificationrequirements for high speed cargo craft which do notproceed, in the course of their voyage, more than 8hours, at operational speed, from a place of refuge.(See 4/1.17.11 for definition of “cargo craft”). Cargocraft which proceed more than 8 hours from a placeof refuge are to comply with either Section 4/9 of the“Rules for Building and Classing Steel Vessels” orSection 4/9 of the “Rules for Building and ClassingSteel Vessels Under 90 Meters (295 Ft) in Length”,as appropriate.

4/9.1.2 Governmental AuthorityAttention is directed to the appropriate governmentalauthority. In each case there may be additionalrequirements depending on the gross tonnage, length,type and intended service of the craft as well as otherparticulars and details. Consideration will be given tofire extinguishing systems which comply with thepublished requirements of the governmental authorityof the country in which the craft is to be registered.

4/9.1.3 Automated Propulsion Machinery SpacesWhere automatic controls for propulsion machineryspaces are installed and it is intended that thepropulsion machinery spaces are either notcontinuously manned at sea or only one person isrequired on watch, the requirements of Section 4/11are to be met.

4/9.1.4 Fire Safety MeasuresThe applicable requirements of Section 3/24 are to becomplied with.

4/9.1.5 Plans and SpecificationsThe plans together with supporting data andparticulars listed in 4/1.11 are to be submitted forreview.

4/9.1.7 Fire Control Plansa Required Information Fire control plans are

to be general arrangement plans showing for eachdeck the provision, location, controls and particulars,as applicable, of fixed fire detection, alarm andextinguishing systems, portable fire fightingappliances and equipment, controls for shutdowns of

the ventilation system, fuel oil pumps and valves,along with details of the means provided for theclosing of openings, and locations of accesses tocritical spaces (such as fire control stations, CategoryA machinery spaces, etc.). For craft where structuralfire protection is required by the Rules, locations andtype of fire retarding bulkheads are to be specified onthe plan.

b Plan Location The fire control plans are to beconspicuously posted on the craft for the guidance ofthe crew.

4/9.3 Fire Pumps, Fire Main, Hydrants andHoses

4/9.3.1 MaterialsMaterials readily rendered ineffective by heat are notto be used for fire mains unless adequately protected.In order to be considered not “readily renderedineffective by heat”, a component is to be certified ashaving passed an applicable recognized fire test, orthe material is to have a melting temperature higherthan the test temperature specified in an applicablefire test.

4/9.3.2 Fire Pumpsa Number of Pumps All craft are to have at

least two fire pumps. For craft of 500 gross tons andabove, the pumps are to be independently power-driven. For craft less than 500 gross tons, only one ofthe pumps need be independently power-driven andone of the pumps may be attached to the propulsionunit. For craft less than 20m (65 ft.) in length, onepower driven pump which may be an attached unit,and one hand operated fire pump may be provided.

b Type of Pumps Sanitary, ballast, bilge orgeneral service pumps may be accepted as firepumps, provided that they are not normally used forpumping oil. If the pumps are subject to occasionalduty for the transfer or pumping of fuel oil, changeover arrangements that prevent operation for firefighting when configured for fuel transfer are to befitted.

c Pump Capacity1 Craft Of 500 Gross Tons And Above

Each of the power-driven fire pumpsrequired by 4/9.3.2a is to have acapacity of not less than two-thirds ofthe quantity required under 4/6.35.3 to


be dealt with by each of the independentbilge pumps but not less than 25 m3/hr(110 gpm) and in any event is to becapable of delivering at least the tworequired jets of water. These pumps areto be capable of supplying the waterunder the required conditions. Wheremore pumps than required are installed,their capacity will be subject to specialconsideration.

2 Craft Less Than 500 Gross Tons Thecapacity of each power driven fire pumpis to be in accordance with item 1 aboveor Table 4/9.3, whichever is less. Handpumps, where permitted, are to have aminimum capacity of 1.1 m3/hr (5 gpm).

d Pressure Power-driven fire pumps are to havesufficient pressure to simultaneously operate theadjacent hydrants as required by 4/9.3.4a.

e Relief Valves In conjunction with all firepumps, relief valves are to be provided if the pumpsare capable of developing a pressure exceeding thedesign pressure of the water service pipes, hydrantsand hoses. These valves are to be so placed andadjusted as to prevent excessive pressure in any partof the fire main system. In general, the relief valve isto be set to relieve at no greater than 1.7 bar (1.75kgf/cm2, 25 psi) in excess of the pump pressurenecessary to maintain the requirements of 4/9.3.2c.

f Arrangement For craft of 500 gross tons andabove, the two main fire pumps including their powersource, fuel supply, electric cables, and lighting andventilation for the spaces in which they are locatedare to be in separate compartments so that a fire inany one compartment will not render both mainpumps inoperable. Only one common boundary isallowed between the compartments in which case thesingle common boundary is to be at least to A-0standard.

No direct access is allowed between thecompartments except that where this is impracticable,an access meeting the requirements in subparagraph gmay be considered.

g Alternative Arrangement Where it isimpracticable to do otherwise, a direct accessbetween the compartments containing the main firepumps may be considered provided:

1 A watertight door capable of beingoperated locally from both sides of thebulkhead, and from a safe andaccessible location outside of thesespaces is provided. The means for thelatter operation is expected to beavailable in the event of fire in thesespaces; or

2 An air lock consisting of two gastightsteel doors. The doors are to be self-closing without any hold backarrangements.

3 In addition to the arrangementsspecified in 1 or 2 above, a secondprotected means of access is to beprovided to the space containing the firepumps.

h Isolation For craft of 500 gross tons andabove, isolating valves and other arrangements, asnecessary, are to be provided so that if a fire pumpand its associated piping within its compartment arerendered inoperable, the fire main can be pressurizedwith a fire pump located in another compartment.

4/9.3.3 Fire Maina Size The diameter of the fire main and water

service pipes is to be sufficient for the effectivedistribution of the maximum required discharge fromtwo fire pumps operating simultaneously except thatthe diameter need only be sufficient for the dischargeof 140 m3/hr (616 gpm).

b Cocks or Valves A valve is to be fitted toserve each fire hose so that any fire hose may beremoved while the fire pumps are at work.

c Cold Weather Protection Fire main systemsare to be provided with drains, circulation loops orother means for cold weather protection.

4/9.3.4 Hydrantsa Number and Position of Hydrants The

number and position of the hydrants are to be suchthat at least two jets of water not emanating from thesame hydrant, one of which is to be from a singlelength of hose, may reach any part of the craft.

b Materials Materials readily renderedineffective by heat are not be used for fire protectionsystems unless adequately protected. See 4/9.3.1.

c Installation The pipes and hydrants are to beso placed that the fire hoses may be easily coupled tothem. In craft where deck cargo may be carried, thepositions of the hydrants are to be such that they arealways readily accessible and the pipes are to bearranged to avoid risk of damage by such cargo.

4/9.3.5 Hosesa General Fire hoses are to be of a type

certified by a competent independent testinglaboratory as being constructed of non-perishablematerial to a recognized standard. The hoses are tobe sufficient in length to project a jet of water to anyof the spaces in which they may be required to beused. The maximum length of hose is not to exceed23 m (75 ft.). Each hose is to have a nozzle and thenecessary couplings. Fire hoses together with anynecessary fittings and tools are to be kept ready foruse in conspicuous positions near the hydrants.


b Diameter Hoses are not to have a diametergreater than 38 mm (1.5 in.). Hoses for craft under20 m (65 ft.) in length may be of a good commercialgrade having a diameter of not less than 16 mm (5/8in.) and are to be have a minimum test pressure of10.3 bar (10.5 kgf/cm2 , 150 psi) and a minimum burstpressure of 31.0 bar (31.6 kgf/cm2 , 450 psi).

c Number of Fire Hoses One fire hose with thecouplings and nozzle is to be provided for eachhydrant. Additionally, at least one spare hose is to bekept on board.

4/9.3.7 Nozzlesa Size Standard nozzle sizes are to be 12 mm

(0.5 in.), 16 mm (0.625 in.) and 19 mm (0.75 in.), oras near thereto as possible. Larger diameter nozzlesmay be permitted subject to compliance with4/9.3.2c. For accommodation and service spaces, anozzle size greater than 12 mm (0.5 in.) need not beused. For machinery spaces and exterior locations,the nozzle size is to be such as to obtain themaximum discharge possible from two jets at thepressure mentioned in 4/9.3.2c from the smallestpump; however, a nozzle size greater than 19 mm(0.75 in.) need not be used.

b Type All nozzles are to be of an approveddual-purpose type (i.e. spray and jet type)incorporating a shut-off. Fire hose nozzles of plastictype material such as polycarbonate may be acceptedsubject to review of their capacity and serviceabilityas marine use fire hose nozzles.

4/9.5 Means for Closing of Openings, Stoppingof Machinery and Oil Containment

4/9.5.1 Ventilation Fans and OpeningsMeans are to be provided for stopping ventilationfans serving machinery and cargo spaces and forclosing all doorways, ventilators, and other openingsto such spaces. These means are to be capable ofbeing operated from outside such spaces and alsofrom a continuously manned control station in case offire. See 4/5A10.1.1.

4/9.5.3 Other AuxiliariesMachinery driving forced- and induced-draft fans,oil-fuel transfer pumps, oil-fuel unit pumps and othersimilar fuel pumps are to be fitted with remoteshutdowns situated outside the spaces concerned andalso from a continuously manned control station sothat they may be stopped in the event of a fire arisingin the space.

4/9.5.5 Oil Tank Suction ValvesExcept for small independent tanks, having a capacityless than 500 liters (132 gal.) every oil suction pipefrom a storage, settling, daily service or lube oil tanksituated above the double bottom, as applicable, is to

be fitted with a valve capable of being closed fromoutside the space where such tanks are located in theevent of a fire. In the special case of deep tankssituated in any shaft or pipe tunnel, control may beeffected by means of an additional valve on the pipeline outside the tunnel. See 4/6.51.4 and 4/6.59.1.

4/9.7 Portable Extinguishers

Portable extinguishers are to be provided in thequantities and locations indicated in Tables 4/9.1 and4/9.2.

4/9.9 Fireman's Outfits

At least two complete fireman's outfits are to becarried on board each craft of 500 gross tons andabove. Each outfit is to consist of an approvedbreathing apparatus, a lifeline, a safety lamp, an axe,non-conducting boots and gloves, a rigid helmet andprotective clothing complying with the followingrequirements. The fireman’s outfits and equipmentare to be stored so as to be easily accessible andready for use and are to be stored in widely separatepositions.

a Breathing Apparatus The breathing apparatusis to be of an approved type and may be either of thefollowing.

1 Smoke Helmet or Mask A smokehelmet or smoke mask with a suitableair pump and a length of air hosesufficient to reach from the open deck,well clear of hatch or doorway, to anypart of the holds or machinery spaces.If, in order to comply with thisrequirement, an air hose exceeding 36 m(120 ft) in length would be necessary, aself-contained breathing apparatus is tobe substituted or provided in addition.

2 Self-contained Breathing Apparatus Aself-contained breathing apparatus,which is to be capable of functioning fora period of at least 30 minutes. Otherperiods of time will be speciallyconsidered. At least one spare charge isto be carried for each required breathingapparatus carried on board.

b Lifeline Each breathing apparatus is to haveattached to its belt or harness, by means of asnaphook, a fire-proof lifeline of sufficient length andstrength.

c Safety Lamp and Axe A safety lamp (handlantern) of an approved type and an axe are to beprovided. Such safety lamps are to be electric, andare to have a minimum burning period of three hours.

d Boots and Gloves The boots and gloves are tobe made of rubber or other electrically non-conducting material.


e Helmet A rigid helmet is to be supplied whichwill provide effective protection against impact.

f Protective Clothing The protective clothing isto be made of material that will protect the skin fromthe heat of fire and burns from scalding steam orgases. The outer surface is to be water resistant.

4/9.11 Machinery Spaces

4/9.11.1 Fire Detection and Fire Alarm SystemsFire detection and fire alarm systems complying with4/9.23 are to be provided for any machinery spacecontaining an internal combustion engine, gas turbine,oil filling station, or switchboards of aggregatecapacity exceeding 800 kW.

4/9.11.2 Fixed Fire Extinguishing SystemFor craft of 500 gross tons and above, Category Amachinery spaces are to be protected by a fixed fireextinguishing system. A fixed fire extinguishingsystem is not required in a machinery space for craftbelow 500 gross tons unless the space contains an oilfuel unit. The fixed fire extinguishing system is tocomply with 4/9.25 and be capable of local manualcontrol as well as remote control from a continuouslymanned control station.

4/9.13 Paint or Flammable Liquid Lockers

4/9.13.1 Fire Detection and Fire Alarm SystemPaint lockers and flammable liquid lockers are to beprovided with fire detection and alarm systemcomplying with 4/9.23.

4/9.13.2 Fixed Fire Extinguishing ArrangementsPaint lockers and flammable liquid lockers are to beprotected by an approved fire extinguishingarrangement. Unless required otherwise by the flagAdministration, the following arrangements will beacceptable:

a Paint lockers and flammable liquid lockers ofdeck area 4 m2 (43 ft2) and more are to be providedwith a fire extinguishing system enabling the crew toextinguish a fire without entering the space. One ofthe fixed arrangements specified below are to beprovided unless subparagraph c is applicable.

1 CO2 system, designed for 40% of thegross volume of the space. See4/9.25.2.

2 Dry-powder system, designed for atleast 0.5 kg/m3 (0.03 lb/ft3).

3 Water spraying system, designed for 5l/m2-min (0.12 gpm/ft2). The waterspraying system may be connected tothe ship's main system.

4 Systems other than those mentionedabove may also be considered.

b For paint lockers and flammable liquid lockersof deck area less than 4 m2 (43 ft2), 6.3 kg (15 lb)CO2 or 4.5 kg (10 lb) dry-powder fire extinguisher(s)may be accepted unless subparagraph c below isapplicable.

c Portable fire extinguishing equipment of thetype and size indicated in b above stowed near theentrance may be accepted for paint lockers of deckarea less than 10 m2 (108 ft2), located outside themain superstructure block and having no contiguousboundaries with accommodation, Category Amachinery spaces, or gas dangerous spaces.

4/9.15 Tanks for Low Flash Point Fuel for GasTurbines

Where fuel with a flash point below 43C (109F) ispermitted by 4/3.9.4 for gas turbines, each spacecontaining a non-integral tank for the low flash pointfuel is to be fitted with a fire detection systemcomplying with 4/9.23 and a fire extinguishingsystem complying with 4/9.25.

4/9.17 Cargo Spaces

For craft of 500 gross tons and above, cargo spaces,except deck areas or refrigerated holds, are to beprovided with an approved automatic smokedetection system complying with 4/9.23 to indicate atthe control station the location of outbreak of a fireand are to be protected by an approved quick-actingfire extinguishing system complying with 4/9.25operable from the control station.

4/9.19 Spaces Containing Dangerous Goods

Craft intending to carry dangerous goods are tocomply with the applicable requirements of ChapterII-2, Part C, Regulations 53 and 54 of InternationalConvention for the Safety of Life at Sea (SOLAS)1974 and Amendments in force.

4/9.21 Accommodation and Service Spaces

A fire detection and fire alarm system complying with4/9.23 is to be provided for accommodation andservices spaces.

4/9.23 Fire Detection and Fire Alarm Systems

Where required, fire detection and fire alarm systemsare to comply with Regulations 7.7.1, 7.7.2 and 7.7.3of the International Code of Safety for High SpeedCraft, as applicable.


4/9.25 Fixed Fire Extinguishing Systems

4/9.25.1 Gas Smotheringa Storage The cylinders for the gas smothering

medium are to be stored outside the protected spacein a room which is situated in a safe and readilyaccessible location. The access doors to the storagespace are to open outwards. The storage room is tobe gastight and effectively ventilated by a ventilationsystem independent of the spaces protected. Anyentrance to the storage room is to be independent ofthe protected space, except that where this isimpracticable due to space limitations, accessbetween the storage location and the protected spacemay be considered for craft under 500 gross tonssubject to compliance with the following:

1 The door between the storage locationand the protected space is to be self-closing with no hold-back arrangements.

2 The space where cylinders are stored isto be adequately ventilated by a systemwhich is independent of the protectedspace.

3 Means are to be provided to preventunauthorized release of gas, such ascontainment behind a break glass.

4 There is to be provision to vent thebottles to the atmosphere in order toprevent a hazard to personnel occupyingthe storage area.

5 An additional entrance to the storagelocation, independent of the protectedspace, is to be provided.

b Design Containers and associated pressurecomponents are to be designed based upon anambient temperature of 55C (131F).

c Alarm Means are to be provided forautomatically giving audible warning of the release offire extinguishing gas into any space to whichpersonnel normally have access. The alarm is tooperate for at least a 20 second period before the gasis released. Alarms may be pneumatically (by theextinguishing medium or by air) or electricallyoperated.

1 Electric If electrically operated, thealarms are to be supplied with powerfrom the main and an emergency sourceof electrical power.

2 Pneumatic If pneumatically operatedby air, the air supply is to be dry andclean and the supply reservoir is to be

automatically kept charged at all timesand is to be fitted with a low pressurealarm. The air supply may be takenfrom the starting air receivers. Any stopvalve fitted in the air supply line is to belocked or sealed in the open position.Any electrical components associatedwith the pneumatic system are to bepowered from the main and anemergency source of electrical power.

d Controls Except as otherwise permittedherein two independent manual control arrangementsare to be provided, one of them being positioned atthe storage location, and the other in a readilyaccessible position outside the protected space.

4/9.25.2 Carbon Dioxide SystemsIn addition to the applicable requirements of theRules, fixed carbon dioxide fire extinguishingsystems are to be in accordance with Regulations7.7.6.1 and 7.7.6.2 of the International Code of Safetyfor High Speed Craft. Fixed low pressure carbon-dioxide systems are to be in accordance with thelatest edition of the ABS Guide for the Use ofRefrigerated (Low Pressure) Carbon-Dioxide as aFire Extinguishing Medium on Board Ship.

4/9.25.3 Foama Fixed High Expansion Foam Systems In

addition to the applicable requirements of the Rules,fixed high expansion foam systems are to be inaccordance with Chapter II-2, Regulation 9 of theInternational Convention for the Safety of Life at Sea(SOLAS) 1974 and Amendments in force.

b Low Expansion Foam System Lowexpansion foam systems may be fitted in machineryspaces in addition to the required fixed fireextinguishing system. In addition to the applicablerequirements of the Rules, fixed low expansion foamsystems are to be in accordance with Chapter II-2,Regulation 8 of the International Convention for theSafety of Life at Sea (SOLAS) 1974 andAmendments in force.

4/9.25.4 Fixed Water Spraying SystemsIn addition to the applicable requirements of theRules, fixed water spraying systems are to be inaccordance with Chapter II-2, Part A, Regulation 10of the International Convention for the Safety of Lifeat Sea (SOLAS) 1974 and Amendments in force.


TABLE 4/9.1Classification of Portable and Semiportable Extinguishers

Fire extinguishers are designated by type as follows: A, for fires in combustible materials such as wood; B, for firesin flammable liquids and greases; C, for fires in electrical equipment.

Fire extinguishers are designated by size where size I is the smallest. Sizes I and II are hand portable extinguishersand sizes III and V are semiportable.

Classification Water Foam Carbon Dry

Type Sizeliters

(US gallons)liters

(US gallons)Dioxidekg (lb)

Chemicalkg (lb)

A II 9 (2.5) 9 (2.5) ---- 2.25 (5)1

B II ---- 9 (2.5) 6.8 (15) 4.5 (10)B III ---- 45 (12) 15.8 (35) 9 (20)B V ---- 152 (40) 45 (100)2 22.7 (50)2

C I ---- ---- 1.8 (4) 0.9 (2)C II ---- ---- 6.8 (15) 4.5 (10)

Notes1 Must be specifically approved as Type A, B, or C extinguisher2 For outside use, double the amount to be carried.


TABLE 4/9.2Portable and Semiportable Extinguishers

Space Classification Quantity and Location

Safety Areas5

Communicating corridors A-II 1 in each main corridor not more than 46m (150 ft.)apart. (May be located in stairways.)

Pilothouse C-I 2 in vicinity of exit. See Note 4.Radio room C-II 1 in vicinity of exit. See Note 4.

Accommodations5

Sleeping accommodations A-II 1 in each sleeping accommodation space. (Whereoccupied by more than 4 persons.)

Service Spaces5

Galleys B-II or C-II 1 for each 230 m2 (2500 ft2) or fraction thereof forhazards involved.

Storerooms A-II 1 for each 230 m2 (2500 ft2) or fraction thereoflocated in vicinity of exits, either inside oroutside of spaces. See Note 4.

Workshops A-II 1 outside the space in vicinity of exit. See Note 4.

Machinery Spaces6

Internal combustion or gas turbine-engines

B-IIand

1 for each 746 kW (1000 hp), but not less than 2nor more than 6. See Note 1.

B-III 1 required. See Note 3.Electric motors or generators of the open

typeC-II 1 for each motor or generator unit. See Note 2.

Notes1 When installation is on weather deck or open to atmosphere at all times, one B-II for every three engines is allowable.2 Small electrical appliances, such as fans, etc., are not to be counted or used as basis for determining number of extinguishers

required.3 Not required on craft of less than 500 gross tons.4 Vicinity is intended to mean within 1 m (3 ft).5 For craft of 500 gross tons and above, at least five extinguishers are to be provided for accommodation spaces, service spaces,

spaces where the ship's radio, main navigating equipment or emergency source of power is located, and locations where the firerecording or fire control equipment is located.

6 At least one of the required extinguishers is to be located outside each main entrance to the machinery space and the remainingrequired extinguishers distributed throughout the engine room located adjacent to high fire risk areas.

TABLE 4/9.3Fire Pump Minimum Capacity for Craft Less Than 500 Gross Tons

Craft Length Minimum Capacity

Less than 20m (65 ft.) 5.50m3/hr (25 gpm)

20m (65 ft.) or greater but less than30.5m (100 ft.)

11.0m3/hr (50 gpm)

30.5m (100 ft.) or greater but lessthan 61m (200 ft.)

14.3m3/hr (66.6 gpm)

61 m (200 ft) or greater Capacity is to be in accordancewith 4/9.3.2c1

PART 4 SECTION 11|1 Shipboard Control and Monitoring Systems

PART 4 SECTION 11

Shipboard Control and Monitoring Systems

4/11.1 General

4/11.1.1 ScopeThe installation of machinery and monitoring of thepropulsion-machinery space in high speed craft is to beso arranged that same permits the normal operation ofthe craft with the propulsion-machinery spaceunattended. However, as an alternative, considerationmay be given to craft installations having minimummanning levels from a centralized location in thepropulsion- machinery space, see Note in 4/11.1.2.The requirements contained in this Section are inaddition to those in other Sections of the Guide.The following Table indicates the applicability of therelevant requirements:

Gross Tonnage (GT)

Craft’s Length (l) Under 500 500 or over

l < 20 m (65 ft) Will be specially

considered

Will be specially

considered

20 m (65 ft)• l • 46

m (150 ft)

Use 4/11.7 Use 4/11.1 -

4/11.5

l > 46 m (150 ft) Use 4/11.7 Use Section 4/11

of the “Rules for

Building and

Classing Steel

Vessels”, as

applicable

Consideration will be given to craft of specialdesign such as surface effect craft, air cushion craft,etc., upon submission of manufacturer's specificationand drawings.

4/11.1.2 Propulsion Class SymbolsControl and monitoring systems for propulsion andmonitoring systems of propulsion-machinery space thatcomply with the relevant requirements, of this Sectionwill be distinguished in the Record as follows. Acertificate indicating the degree of automation,particulars and operating limitations, if any, will beissued. A symbol preceded by !!!! (Maltese cross)signifies that the installations have been assembled and

installed under survey by the Surveyor. A symbolwithout !!!! (Maltese cross) signifies that pertinentcontrol and monitoring systems have not beenassembled and installed under survey but havesubsequently been surveyed and satisfactorily reportedupon by the Surveyor.

a Craft ≥≥≥≥ 500 GT and ≤≤≤≤ 46 m (150 ft) inLength

1 ACCU Symbol Control and monitoringsystems complying with 4/11.3 will bedistinguished in the Record by the symbolACCU.

2 ABCU Symbol Control and monitoringsystems complying with 4/11.5 will bedistinguished in the Record by the symbolABCU.

Note: ACCU or ABCU class symbol may be granted tocraft of < 500 GT and a length of 20 m (65 ft)• l• 46 m (150 ft), provided that the applicablerequirements in 4/11.1 through 4/11.5 of thisSection are met. Likewise, ACC class symbol maybe granted to craft provided the applicablerequirements in Section 4/11 of the “Rules forBuilding and Classing Steel Vessels” are met.

4/11.1.3 DefinitionsThe following definitions apply for the purpose of thisSection.

a Machinery Space See 4/1.17.b Manned Space Means any space assigned at all

times with crew members needed to locally supervisethe operation of the specific machinery or systeminstalled in the space.

c Automatic Control Type of control which isself-regulating in carrying out ordered instructionwithout action by the operator.

d Remote Control Control of a device by anoperator from a distance through mechanical, electrical,electronic, pneumatic, hydraulic, electromagnetic(radio) or optical means or their combination.

e Local Control Control by an operator ofmachinery through a device located on or adjacent tothe controlled machinery.

f Remote Station A permanent installation fittedwith effective control and/or monitoring means andlocated at a distance from the specific machinery.


g Centralized Control and Monitoring Station Aremote station designated as the central location wherethe necessary instrumentation required to maintain thecontrol and monitoring of the specific machinery isfitted, and which is equivalent at least as if themachinery were under local supervision.

h Operating Compartment Means the enclosedarea from which the navigation and control of the craftis exercised.

i Instrumentation A monitoring deviceincluding sensing and transmitting component.

j Monitoring The display and alarming of theoperational status of a specific machinery/system.

k Display Systems Display systems are thosewhich display operating machinery parameter valuessuch as pressure, temperature, liquid flow, motorrunning, etc., or the sequential operation of the system'process.

l Alarm A visual and audible signal of apredetermined out of limits parameter for the controlledand/or monitored machinery or system.

m Summary-alarm A common alarm activated byany abnormal condition of the monitored machinery orsystem.

n Safety Systems Systems which provideautomatic actions in response to faults that maydevelop too fast to be countered by manualintervention. The safety systems are intended tooperate automatically in case of faults within themachinery plant for the purpose of:

1 Temporarily adjusting the operation of themachinery to the prevailing conditions (byreducing the output of the machinery), or

2 Restoring the normal operating conditions (bystarting of standby units), or

3 Protecting the machinery from criticalconditions by stopping the machinery(shutdown).

o Emergency Shutdown Systems Systemsintended for manual activation in an emergency to stopa particular system's function or machinery operation.

p Fail-safe Fail-safe means that upon failure ormalfunction of a component, sub-system or system, theoutput automatically reverts to a predetermined designstate of least critical consequence.

q Independent As applied to two systems, meansthat one system will operate with the failure of any partof the other system including power sources and itssupply connection. However, for electrical systemswhich are not required to have an emergency source ofpower as the standby power source, failure of thepower source may be excluded from this criteria.

r Computer-based System A computer-basedsystem consists of one or more electronic or opticaldevices which together with their peripherals and usingfixed or programmable logic and memories, processesinput data and output signals for purposes of display,alarm, control or storage. The system is understood to

comprise all required hardware, i.e., microprocessors,monitor (video display unit), keyboard, etc., and datatransmission path (data highways).

s Non-volatile Memory Memory which does notrequire power to retain the stored data.

t Computer Monitor (Video Display Unit) Adevice where computer information or data isdisplayed.

u ABS Type Approval Program Certificationscheme whereby ABS certifies, at the request of theequipment manufacturer, that the specific equipmentconforms to cited standards and to cited ratings whichABS has verified by engineering analysis and that anappropriate quality system is in place to manufacture aproduct of consistent quality.

v Integrated Propulsion Machinery Apropulsion machinery having its auxiliaries (fuel oilpumps, cooling water pumps, etc.), necessary fornormal operation driven by the engine, the reductiongear or the propulsion shaft.

4/11.1.4 Required Plans and DataPlans and data associated with control and monitoringof machinery and systems are to be submitted forapproval in accordance with 4/1.11 and are to includethe following:

a A list of electrical, pneumatic or hydraulicequipment associated with the particular systems. Thisis to include manufacturer's name, model number,material, ratings, degree of protection, permissibleangles of inclination and location of installation withinthe craft.

b A list of all major components installed withinthe particular equipment (i.e., control console, etc.) andthe data as required in 4/11.1.4a.

c Certificates or test reports, as appropriate,attesting to the suitability of the particular equipment incompliance with the environmental criteria set forth in4/11.3.7 and 4/11.3.8, as applicable. For equipmentthat have been already certified by the Bureau andprovided their certification remains valid, thesubmission of a copy of pertinent certificate willsuffice. See 4/11.3.8b.

d Plans showing the location of control andmonitoring stations, controlled equipment andpiping/cable runs, etc.

e Arrangements and details of the controlconsoles and panels including plan views and elevationdetails, installation details and wiring data (rating,construction standard, insulation type,armored/unarmored/ shielded/non-shielded,temperature rating, flame-retardant properties, etc.).

f A list of all cables connecting equipmentassociated with the systems. This is to includeconstruction standard, electrical rating, insulation type,armored/unarmored/ shielded/non-shielded,temperature rating, size and connected load's powerconsumption requirements.


g A complete operational description of thecontrol and monitoring systems including a list ofalarms and displays and functional sketches ordescription of all special valves, actuator, sensors andrelays.

h A simplified one-line diagram (electrical andpiping) of all power and control and monitoringsystems. This is to include power supplies, circuit orpiping protection ratings and settings, cable or pipesizes and materials, rating of connected loads, etc.

i A schematic diagram of all control, alarm,display and safety systems.

j For computer-based systems, the following is tobe included:

1 Overall description and specification of thesystems and equipment.

2 Block diagrams for the computer hardwareshowing interfacing between the workstations, input/output (I/O) units, localcontrollers, traffic controllers, data highways,etc.

3 Logic flow chart or ladder diagrams.4 Description of the alarm system indicating the

ways it is acknowledged, displayed on themonitor or mimic display board, etc.

5 Description of the system redundancy andback-up equipment, if any.

6 Description of the data communicationprotocol including anticipated data processresponse delays.

7 Description of the system' security protocol toprevent unauthorized program changes whichmay compromise the integrity of the systems.

8 Description of the system with regard to thedegree of independence or redundancyprovided for the control systems,alarm/display systems and safety systems.

9 Description of system's task priorities.10 Where applicable, description of UPS

(uninterruptable power supply) and theircapacities including system's powerconsumption.

11 Equipment ratings and environmentalparameters.

k Installation methods (electrical, pneumatic andhydraulic). This is to include details of cable or piperuns, separation of cables of different voltage ratingand insulating rating, cable tray laying, deck orbulkhead penetration, prevention of magneticinterference, etc. See also 4/11.3.7e.

l A matrix chart for each of the systems indicatingthe following, as applicable, upon activation of a givenalarm or safety action:

1 Name, device designations and type, andlocation of alarms.

2 Preset parameter values, if any.

3 Automatic tripping and other safety provisionsof controlled equipment.

4 Location of control stations where shutdown,and control and monitoring power supplytransfer devices are fitted.

5 Special remarks, if any.

4/11.1.5 Tests and Surveysa Installation Tests Control and monitoring

systems are to be subjected to tests witnessed by theSurveyor during and after installation onboard asoutlined in this Section.

b Periodical Surveys The continuance ofcertification is subject to periodic survey of the controland monitoring systems installation as outlined in1/3.19.

Propulsion Control and MonitoringSystems and Monitoring Systems forPropulsion-machinery Space

4/11.3 Craft Classed with ACCU Symbol

4/11.3.1 GeneralThe requirements in this sub-section are applicable tocraft fitted with 1) the means to control and monitor thecraft’s propulsion, steering and trim related machineryand the means to monitor a periodically unattendedpropulsion-machinery space from the operatingcompartment, and 2) similar controlling an monitoring

means, as required in 4/11.3.10, at a suitably locatedcentralized control and monitoring station. See4/11.1.2a1.The requirements in this sub-section cover theoperation required for propulsion machinery start-up,safe sailing during open sea and maneuveringconditions, and do not cover operations after anchoringor mooring.

4/11.3.2 Propulsion Control Systemsa Characteristics Propulsion control systems are

to be of the fail-safe type and designed to precludedetrimental mechanical or thermal overloads to thecontrolled machinery.

b Propulsion Control Capability Under allsailing conditions, including maneuvering, the speed,direction of thrust and, where applicable, the pitch ofthe propeller, is to be fully controllable from the remotepropulsion control station. The remote control is to beperformed, for each independent propeller, by a controldevice so designed and constructed that its operationdoes not require particular attention to the operationaldetails of the machinery. Additionally, where multiplepropellers are designed to operate simultaneously, theymay be controlled by one control device.


c Interlocks Controlled machinery or systemsfitted with more than one remote propulsion controlstation are to be provided with interlocking means topreclude simultaneous control or unauthorized transferto associated remote stations not in control. However,propulsion control units interconnected with a specificassociated remote control station and which are withinsight of each other, may be accepted without interlocks.

d Propulsion Starting1 An alarm is to be provided in the propulsion-

machinery space and at any propulsion controlstation fitted outside the propulsion-machineryspace to indicate a low level starting conditionwhich is to be set at a level to permit furthermain engine starting operations. Whereautomatic starting of the propulsion machineryis fitted, the number of consecutive attempts toautomatically start an engine is to be limited inorder to safeguard sufficient capacity for localstarting from the propulsion-machinery space.See also 4/4.15.

2 Propulsion machinery control system is to bedesigned so that it will automatically inhibitthe starting of the propulsion machinery whereconditions exist which may damage thepropulsion machinery, i.e., shaft turning gearengaged, insufficient lubricating oil pressure,etc.

e Transfer of Control Transfer of propulsioncontrols from a remote control station under operationto other associated remote stations is to be possible bya request from the receiving station and acceptance bythe station in operation, or vice versa. However, thepropulsion control station in the propulsion-machineryspace is to be capable of assuming control at all timesand to block orders from other associated remotecontrol stations, if fitted. Considerations will be givento cases where, due to the intended craft's service andoperational requirements, it may be necessary for otherassociated stations to have override controls over theremote propulsion control stations in the propulsion-machinery space.

All propulsion control stations are to haveindicators showing which station is in control.

f Propulsion Control Orders Propulsionmachinery orders from the operating compartmentare to be indicated in the centralized control station ormaneuvering platform in the propulsion-machineryspace, as appropriate.

g Failure of Propulsion Control or Failure ofControl Transfer In the event of failure of thepropulsion control system or failure of control transfer,the propulsion units are to continue to operate at thelast ordered speed and direction of thrust of thepropellers until local control is in operation or controlpower is safely resumed. However, considerations willbe given to special cases, where due to the intendedcraft's propulsion design and operational requirements,it may be necessary to automatically bring the craft tolow speed without hazarding passengers or the craft.

h Critical Speeds of Propulsion DrivesAdequate means are to be provided at the remotepropulsion control station to alert the station operatorof prolonged operation of the propulsion drives withinbarred speed ranges.

i Automatic Propulsion Controls Automaticpropulsion control systems are to be designed tomaintain the controlled machinery within pre-setparameters and to ensure the machinery operation inthe correct sequence and time intervals. Deviationfrom these pre-set conditions is to force the sequentialcontrols to a safe sequence stage that will not bedetrimental to the propulsion machinery and overallsafety of the craft. Additionally, the automaticpropulsion control system is to be designed andarranged so that a failure in the system is not tocompromise the integrity nor the manual operation ofthe propulsion machinery..

j Automatic Shutdown If the control systemautomatically shuts down the main propulsionmachinery for any reason, this is to be alarmed at theremote propulsion control station(s).

k Local Propulsion Controls Remotely operatedpropulsion machinery or systems are to be providedwith effective means of independent controls at or inthe proximity to the propulsion machinery or systems.Means are to be provided locally to disconnect oroverride other associated remote stations or disableautomatic control, if any.

4/11.3.3 Alarm Systemsa Characteristics Alarm systems are to be of the

self-monitoring type and designed so that a fault in thealarm system is to cause it to fail to the alarmedcondition. Additionally, they are not to react to normaltransient conditions or spurious signals.

b Independence Alarm systems are to beindependent of control and safety systems except thatcommon sensors will be acceptable as permitted in4/11.3.4c.

c Visual and Audible Alarms Alarms are to beboth audible and visual and are to be provided at thecontrol stations, as required in this Section. Alarms areto clearly identify the system and service of the faultedmachinery or machinery components. Visual alarmsare to be displayed in a distinguishable manner suchthat alarms for similar machinery or systems aregrouped together and the colors representing aparticular function or condition remain uniform. Visualalarms are to flash when first activated. Audible alarmsassociated with machinery are to be of distinctive tonefrom other alarms such as fire-alarm, general alarm, gasdetection, etc. and they are to be of sufficient loudnessto attract the attention of duty personnel; for spaces ofunusual high noise levels, a beacon light or similar,installed in a conspicuous place is to supplement any ofthe audible alarms in such spaces; however, red lightbeacons are only to be used for fire alarms.


A fault in the visual alarm circuits is not to affectthe operation of the audible alarm circuits. Forcomputer-based system, see 4/11.3.5.

d Acknowledgment of Alarms Alarms are to beacknowledged by manually changing the flashingdisplay of the incoming alarm to a steady display andby silencing the audible signal; the steady state lightdisplay is to remain activated until the fault condition isrectified. Alarming of other faults that may occurduring the acknowledgment process is not to besuppressed by such action and is to be alarmed anddisplayed accordingly. The silencing of the audiblealarm from an associated remote control station is notto lead automatically to the silencing of the originalalarm at the centralized control and monitoring station.

e Disconnection and Resumption of AlarmFunctions Alarm circuits may be temporarily disabledfor maintenance purposes or during initial start-up ofmachinery provided that such action is clearly indicatedat the associated station in control. . However, suchalarm is to be automatically re-activated after a presettime period.

f Summary-alarms In addition to requiredalarms to be fitted at the centralized control andmonitoring station, visual alarms may be displayed andalarmed at other associated remote control stations assummary-alarms.

g Built-in Testing Alarm systems are to beprovided with effective means for testing all audibleand visual alarms and indicating lamps withoutdisrupting the normal machinery or system operation.Such means are to be fitted in the associated remotestations.

4/11.3.4 Safety Systemsa General Safety systems are to be provided as

required in this Section. Considerations will be givento the manual activation of safety systems provided thatmeasures are taken, by the inherent design of thesystem or by suitable arrangements, to retard theescalation of the abnormal condition and to alertpersonnel to take the appropriate action prior to thedeveloping of a dangerous condition.

b Characteristics Safety systems are to be of thefail-safe type and are to respond automatically to faultconditions that may endanger the machinery or safetyof the crew. Unless otherwise required in this Sectionor specially approved, this automatic action is to causethe machinery to take the least drastic action first, asappropriate, by reducing its normal operating output orswitching to a stand-by machinery and last, by stoppingit, i.e., disrupting source of fuel or power supply, etc.

c Independence Safety systems for differentparts of the machinery plant are to be independent ofeach other. The safety system intended for thefunctions specified in 4/11.1.3n3 (shutdown) is to becompletely independent of the control and alarmssystems so that a failure in these systems will not

prevent the safety system from operating. However, forthe functions specified in 4/11.1.3n1 and .3m2,complete independence of the safety systems from thecontrol and alarm systems is not required.

d Activation Each safety action is to be alarmedat the associated remote station. When both an alarmand a safety action are required for a specific failurecondition, the alarm is to be activated first.

e Resumption of Operation Machinery that isstopped as a result of a safety action, is not to resumeoperation unless it is reset manually.

f Override of Safety Provisions Remote overrideof safety provisions is not permitted for the following:

1 Shutdown of propulsion gas turbines uponfailure or loss of the oil lubricating system.See 4/3.13.3 of the “Rules for Building andClassing Steel Vessels”.

2 Shutdown of prime-movers for propulsion andship's service diesel-generators uponactivation of overspeed mechanism. See4/5C2.17 of these Rules and 4/4.11.6 of the“Rules for Building and Classing SteelVessels”. However, considerations will begiven to specific cases where due to the craft'sdesign and operational requirements, it may benecessary to momentarily override thepropulsion machinery over the overspeedautomatic shutdown.

3 Shutdown of prime-movers upon failure orloss of oil lubricating system to forced-lubricated propulsion or ship's service diesel-generators. See 4/5C2.13.

Remote overrides for other safety provisions asspecified in subject Section 4/11 are to be so arrangedthat they cannot go unnoticed and their activation andcondition are to be alarmed and indicated at theassociated remote station. The override is to bearranged to preclude inadvertent operation and is not todeactivate alarms associated with safety provisions.The override mechanism to disconnect safetyprovisions is to be fitted at the associated remotestation except that same may be fitted at the centralizedcontrol and monitoring station instead. Overrides fittedat the operating compartment are to be operable onlywhen in the operating compartment control mode.

4/11.3.5 Computer-based Systemsa General Computer-based systems are to be

designed so that failure of any of the system'scomponents will not cause unsafe operation of thesystem. Hardware and software serving vital and non-vital systems are to be arranged to give priority to vitalsystems.

b Independence Control, alarm and safetyshutdown system functions are to be arranged such thata single failure or malfunction of the electroniccomputer equipment will not affect more than one ofthese system functions. This is to be achieved by


dedicated equipment for each of these functions withina single system, or by the provision of back-upequipment, or by other suitable means considered notless effective.

c Visual Display of Alarms1 Incoming Signals In addition to the

requirements contained in 4/11.3.3, and whendisplayed by way of a computer monitor(video display unit), alarms are to bepresented in an identifiable manner, and whendisplayed, alarms are to appear in thesequence as the incoming signals are received.Alarming of incoming fault signals are toautomatically appear on the screen, to alert theon-duty personnel, regardless of whether thecomputer and monitor (video display unit) arein a mode other than the monitoring mode,i.e., computing or displaying other system'smimic or schematic diagrams.

2 Unrectified Alarms Alarms associated withfaults which have not been rectified may bedisplayed in a summarized fashion until all thefaults have been dealt with.

3 Computer Monitor (Video Display Unit)Displays on the computer monitor (videodisplay unit) are to be clearly visible underambient lighting conditions Computermonitors on the operating compartment are tobe provided with dimmers to control displaylighting. Data displayed on computermonitors are to be readable by the operatorfrom the normal operating position.

4 Response Delay The time limit on responsedelays for safety and alarm displays is not toexceed 2 seconds.

d Memory Capacity and Response TimeComputer system's memory is to be of sufficientcapacity to handle the operation of all computerprograms (software) as configured in the computersystem. The time response for processing andtransmitting data is to be such that undesirable chain ofevents may not arise as a result of unacceptable datadelay or response time during the computer system'sworst data overload operating condition (multi-taskingmode).

e Data Loss and Corruption To preclude thepossible loss or corruption of data as a result of powerdisruption, program and associated memory dataconsidered to be essential for the operation of thespecific system is to be stored in non-volatile memoryor a volatile memory with a secure uninterruptablepower supply (UPS).

f Power Supply Disruption The system'ssoftware and hardware is to be designed so that uponrestoration of power supply, after power failure,control and monitoring capabilities can immediately beavailable after the pre-established computer controlaccess (sign-in) procedure has been completed.

g Parameters and Program Changes Alterationof parameters that may affect the system's performanceare to be limited to authorized personnel by means ofkeyswitch, keycard, password or other approvedmethods. Similarly, computer program or system'sconfiguration changes are to be effected only byauthorized personnel.

4/11.3.6 Supply, Arrangement and SystemProtection of Control and Monitoring Systems

a Supply and Arrangement1 General The power distribution to control

systems, alarm/display systems (considered asone for the purpose of this requirement) andsafety systems is to be provided with theirindividual circuits so that a fault in one of thesystems cannot cause loss of the othersystems. Their supply status and failurecondition is to be displayed and alarmed at theassociated remote propulsion station.

2 Electricala Power Supply Two means of power

supply for the circuits in 4/11.3.6a are tobe provided, one of which is to beconnected to the emergency switchboard(distribution board). The supply circuits in4/11.3.6a1 may be either connecteddirectly or supplied via a common supplyfeeder connected to their respectiveswitchboards (distribution boards) and areto be provided with short-circuit protectionat such boards. The power supply statusand failure condition of each of the circuitsin 4/11.3.6a1 is to be monitored on theload side of the feeder's protective device.Additionally, control and monitoringsystems that may require constant powersupply are to be provided with anuninterruptable power supply (UPS)system of sufficient capacity to cover therequired main power transition period.See 4/11.3.5e.

b Power Supply Transfer Transfer of powersupply is to be effected automatically. Thepower supply transfer device is to bearranged for manual operation.

c Continuity of Power Provision is to bemade for automatic starting andconnecting to the main switchboard of astandby generator of sufficient capacity topermit propulsion and steering and toensure the safety of the craft withautomatic re-starting of the essentialauxiliaries including, where necessary,sequential operations. This standbyelectric power is to be available in no morethan 45 seconds. To satisfy theaforementioned requirement, the operationof propulsion machinery and vital servicesmay be at reduced power.


3 Hydraulic The hydraulic pumps for controland monitoring systems are to be fitted induplicate. The pump suctions are to be from areservoir of sufficient capacity to contain allthe fluid when drained from the system,maintain the fluid level at an effective workingheight and allow air and foreign matter toseparate out. The pump suctions are to besized and positioned to prevent cavitation orstarvation of pump. The hydraulic fluid is tobe suitable for its intended operation.

4 Pneumatic Compressed air for control andmonitoring systems is to be available from atleast two air compressors. The starting airsystem may be used as a source of control air.The air pressure to the pneumatic control ordisplay system is to be automaticallymaintained at a level required for theoperation of the installation. Means to preventthe accumulation of moisture is to beprovided. Additionally, means are to beprovided to assure the supply, from a safearea, of clean, dry and oil-free air to thepneumatic controls or displays.

b System Protection1 Electrical Circuits are to be arranged so that a

fault in one circuit will not cause maloperationor failure on another circuit or system. It is tobe possible to isolate the faulted circuit.Additionally, systems are to be protectedagainst accidental reversal of power supplypolarities, voltage spikes and harmonicinterference, and in no case is the system'stotal harmonic distortion to exceed 5%.

2 Hydraulic Pipe systems subject to pressurebuild-up that may exceed the rated pressure ofthe pipe and associated components are to beprovided with suitable pressure relief devicesfitted on the pump’s discharge side. Eachrelief valve is to be capable of relieving notless than full pump flow with a maximumpressure rise of not more than 10% of therelief valve setting.

3 Pneumatic The requirements in 4/11.3.6b2are to be complied with, as applicable.

4/11.3.7 Equipment Construction, Design andInstallation

a General Equipment associated with remote orautomatic control and monitoring systems is to meetcompliance with the requirements contained herein.Deviation from the environmental requirements such astemperature, humidity and corrosion will be consideredfor equipment intended for installation in ambientcontrolled rooms or enclosures. See also 4/11.3.7e2and 4/11.3.7e7. Similarly, where equipment is installedin environments having parameters other than those asspecified in Table 4/11.1, i.e., cryogenic or highly

corrosive environments, etc., special considerationcorresponding to those of the operating environmentwill be required.

b Electrical Equipment is to be constructed ofrobust, durable and flame-retardant material. It is to bedesigned to incorporate the degree of enclosureprotection as required in Table 4/5B.1. Wiring andcables are to meet the requirements contained in4/5C4.11.4 and 4/5C7, respectively.

Non-current carrying metal parts are to beeffectively earthed.

c Hydraulic Hydraulic pumps, actuators, motorsand accessories are to be suitable for the intendedservice, compatible with the working fluid and are to bedesigned to operate safely at full-power conditions. Ingeneral, the hydraulic fluid is to be non-flammable orhave a flash point above 157C (315F).

d Pneumatic Air compressors, actuators, motorsand accessories are to be suitable for the intendedservice and have working and other parts that will notbe damaged or rendered ineffective by corrosion.

e Installations1 General The installation of equipment

associated with control and monitoringsystems is to be carried out taking intoconsideration adverse effects that may beintroduced by their exposure to unintendedtemperatures, weather, vibration conditions,falling objects or liquid, electromagneticinterference, high voltage systems, electricnoise, etc. Additionally, the installation is tofacilitate the checking, adjustment andreplacement of components, including filtersand sensing devices, without disrupting thenormal operation of the system, as far aspracticable.

2 Ranges in Ambient Temperatures For theselection and installation of equipmentassociated with control and monitoringsystems, a temperature range of 5C (41F) to55C (131F) is to be considered for machineryspace, control rooms, accommodations andoperating compartment. When equipment islocated inside panels or cubicles,consideration is to be given to the temperaturerise inside those panels due to the dissipationof heat from its own components. See alsoNote 1 of Table 4/11.1.Where compliance with the above temperatureranges cannot be met, consideration will begiven to the installation of equipment per4/11.3.7e7.

3 Electromagnetic and Conducted InterferenceIn general, the installation of equipmentassociated with control and monitoringsystems in areas of unusual electromagneticsources is to be avoided. Where the valuesper Table 4/11.1 may be exceeded,


appropriate measures are to be implemented toreduce the effects of electromagnetic andconducted interference. To avoidelectromagnetic noise caused by circulatingcurrents, the conductive shield and cablearmor is to be earthed only at one end of thecable. Description of the preventive measuresto be followed is to be submitted for review.

4 Shielded Cables To avoid possible signalinterference, cables for control andmonitoring systems occupying the same cabletray, trunk or conduit with power cables are tobe of the shielded type.

5 Electrical Grounding Control and monitoringsystems are not to have common earthconductors with systems of higher voltagelevel.

6 Condensation Electrical equipment liable tobe exposed to ambient temperaturefluctuations is to be provided with means toprevent accumulation of moisture inside thecomponent's enclosure, i.e., by the provisionsof space heaters that automatically energizesupon shutdown or disconnection of theelectrical component.

7 Cold Environment Electrical equipmentwhich may be adversely affected by theexposure to temperatures lower than those forwhich they are designed for, is to be providedwith suitable heating arrangements so that theymay be readily operated when needed. See4/11.3.7e2.

8 Protection Against Falling Liquids orLeakage of Fluid Medium Electricalequipment is not to be installed in the samecompartment or cabinet containing equipmentor pipes carrying water, oil or steam unlesseffective measures are taken in order toprotect the electrical equipment from possiblefluid leakage, i.e., welded connections,physical isolation together with suitabledraining arrangements, etc.

9 Measuring and Sensing Devices Theinstallation of measuring and sensing elementsis to permit their easy access for functionaltesting or replacement.

10 Marking All units, controllers, actuators,displays, terminal strips, cable and test points,etc. are to be clearly and permanently marked.Their systems and system's functions are to beincluded so that they can be easily identifiedin associated drawings and instrument lists.

4/11.3.8 Equipment/components QualificationsEquipment associated with the automatic/remotecontrol and monitoring of the propulsion machinery areto comply with the following requirements:

a Testing of Equipment1 General Testing is to be carried out in

accordance with Tables 4/11.1 and 4/11.2.Where environmental operating parametersexceed those specified herein, specialarrangements will be considered. See4/11.3.7a.With the exception of field sensors, allrequired system's components are to besubjected to these tests. For computer-basedsystems, the equipment to be tested includesmicroprocessors, storage devices, powersupply units, signal conditioners,analog/digital converters, computer monitors(video display units), keyboards, etc. but itexcludes printers, data recording or loggingdevices not required in this Section.

2 Documentation The manufacturer orassembler of the associated equipment is toprovide documented evidence indicating thatthe equipment meets the criteria specified inTables 4/11.1 and 4/11.2. Additionally, forcomputer-based systems, evidence is to beincluded to indicate that semiconductordevices such as CPU, non-volatile memories,etc., have been subjected to a burn-in test for aperiod not less than 72 hours, at an operatingtemperature of 70C (158F), with powerconnected to the device.

3 Environmental Testing Environmental testingon the associated equipment is to be carriedout in accordance with the criteria outlined inTable 4/11.1. With the exception of theinclination and vibration tests, allenvironmental tests are to be carried out andsatisfactorily reported upon by themanufacturer and/or assembler; such testreport is to be submitted for review.Inclination and vibration tests are to be carriedout in the presence of the Surveyor at themanufacturer's or assembler's plant, or at anindependent testing laboratory in accordancewith Table 4/11.1.

4 Performance Testing Performance testing inaccordance with Table 4/11.2 are to be carriedout in the presence of the Surveyor at thetesting plant or after installation of theequipment onboard the vesselcraft. Wheredeemed necessary by the Surveyor, insulationresistance and high voltage tests in accordancewith Table 4/11.1 may be required to becarried out.

b Type Approval of Automatic or RemoteControl and Monitoring Equipment Equipment thatmeets the requirements contained in 4/11.3.8a iseligible to be certified under the ABS Type ApprovalProgram upon formal request by the equipmentmanufacturer. See also 4/11.1.4c.


4/11.3.9 Station in the Operating CompartmentEffective control of the propulsion machinery, from theoperating compartment, is to be performed withautomatic performance of all associated functions,including, where necessary, means of preventingoverload of the propulsion machinery. The requiredautomatic control means to operate the propulsionmachinery are to be capable of meeting load demandsfrom standby to full system rated load under alloperating conditions, without the need for manualadjustment or manipulation.

The operating compartment control station is toinclude the controls, displays and alarms as required inTable 4/11.3. In addition, the following controlsarranged for easy reach of the crew member for use inan emergency are to be provided at the operatingcompartment:

a Stopping the main propulsion and auxiliarymachinery. The stopping device for the mainpropulsion is to be independent of the navigatingbridge control system.

b Disconnecting all electrical power sourcesfrom the normal power distribution system (theoperating control is be so arranged to preclude itsinadvertent or careless operation).

c Stopping the machinery-space ventilationblowers and closing of openings as per 4/9.5.1.

d Stopping all fuel-oil pumps and forced-draftblowers.

e If provided, closing machinery-spaceskylights.

f Closing machinery-space watertight and fire-resistant doors.

g Closing propulsion-machinery space fuel oiltanks suction valves. (See 4/9.5.5).

h Starting the emergency generator orconnecting a source of emergency power, unlessautomatic operation is provided.

i Means for starting any one of the fire pumps(inclusive of the one located outside the propulsion-machinery space) including associated valves necessaryto deliver required capacity to the fire main.

j Releasing of the fire-fighting media for thepropulsion-machinery space This release is to bemanual and not initiated automatically by signals fromthe fire-detecting system.

4/11.3.10 Centralized Control and MonitoringStationThe centralized control and monitoring station is toinclude adequate controls, displays and alarms neededto maintain normal and safe operation of the propulsionmachinery and monitor associated ship' servicesystems, electrical power generating machinery, andpropulsion-machinery space. The installed control andmonitoring system is to provide the same degree ofcontrol as if the propulsion-machinery space wasmanned. See Tables 4/11.4 through 4.11.8 for required

controls, alarms and displays to be fitted at suchstation.

4/11.3.11 Automatic Transferring of VitalAuxiliary PumpsThe means for the automatic starting and transferring ofrequired standby vital auxiliary pumps associated withpropulsion are to be provided. The automatic startingand transferring of vital auxiliary pumps is to bealarmed at the centralized control and monitoringstation. The aforementioned is applicable to thefollowing machinery/systems:

a Propulsion Machineryb Electrical Power Generating Machineryc Controllable Pitch Propellers (C.P.P)d Sea Water Main Circulating System e Propulsion-machinery Space Bilge Systemf Fuel Oil Transfer or Service System This is

applicable to pumps associated with settling and dailyservice tanks.

4/11.3.12 Propulsion Gas TurbinesThe centralized control and monitoring station is to beprovided with the alarms and displays as listed in

Table 4/11.6.

4/11.3.13 Propulsion Diesel Enginesa Lubricating Oil In the event of loss of

lubricating oil, there is to be an automatic shutdown ofthe main engine.

b Overspeed An overspeed condition is to causethe automatic shutdown of the main engine.

c Controls and Instrumentation The centralizedcontrol and monitoring station is to be provided withthe safety provisions, alarms and displays as listed inTable 4/11.5 .

4/11.3.14 Electric PropulsionFor electric propulsion driven craft, in order to preventnuisance tripping of the main generator circuitbreakers, a power management system is to beprovided and arranged so that when the powerrequirement for the propulsion motors exceeds the on-line generating capacity, the power management systemis to take, automatically, a corrective action, such asreduction of power, shedding of non-essential loads,etc. The centralized control and monitoring station isto be provided with the alarms and displays as listed inTable 4/11.7.

4/11.3.15 Electrical Power Generating MachineryThe centralized control and monitoring station is to beprovided with the alarms and displays as listed in Table4/11.8.


4/11.3.16 Fuel Oil Settling and Daily ServiceTanks

a General Low level conditions of fuel oilsettling and daily service tanks are to be alarmed at theoperating compartment and centralized control andmonitoring station; additionally, adequate interlockmeans to prevent tank over-pressurization or overflowspillages are to be provided.

b Automatic Filling The fuel oil settling or dailyservice tanks are to be of a capacity sufficient for atleast 8 hours operation at normal power. Thearrangements are to include high level alarm togetherwith automatic filling-pump shutdown and automaticpump start-up at a predetermined low level, in additionto the arrangements per 4/11.3.16a.

c Heating Arrangements See 4/11.3.18b3.

4/11.3.17 Propulsion and Associated MachineryStart-upStarting of the propulsion and associated machinery orpreparing the engines for sea may be performedmanually, but if done automatically this is to beprogrammed that the propulsion machinery cannot bestarted until all engine auxiliaries are functioningcorrectly.

4/11.3.18 Arrangement and Monitoring ofMachinery Space

a Bilges 1 General The propulsion-machinery space is

to be provided with a bilge water-levelsystem to detect excessive water influx or risein the propulsion-machinery space bilges, atthe various angles of craft's heel and trim; thebilge wells are to be large enough toaccommodate the normal drainage. Excessivewater influx or rise in the bilge wells is to bealarmed at the centralized control andmonitoring station. See also Tables 4/11.3and 4/11.4 for alarms and displays.

2 Excessive Automatic Starting of Bilge PumpsMeans are to be provided to indicate, at thecentralized control and monitoring station,when the influx of liquid is greater than thepump capacity or when the pump is operatingmore frequently than would normally beexpected. Additionally, special attention is tobe given to oil pollution preventionrequirements.

b Fire Prevention To minimize the outbreak offire, the following is to be provided:

1 In high pressure fuel-oil piping (see 4/4.7.3 ofthese Rules and 4/3.25.3 of the “Rules forBuilding and Classing Steel Vessels”), an oilleakage condition is to be alarmed at theoperating compartment and at the centralizedcontrol and monitoring station.

2 Drip trays for collecting oil as required in4/6.7.13 are to be of suitable height andprovided with suitable drainage to a collectingtank incorporating a high level alarm audibleat the centralized control and monitoringstation.

3 Where heaters are provided in fuel systems,the required alarms in 4/6.49.3 are to belocated at the centralized control andmonitoring station.

4 Fuel oil heaters, purifiers, pumps, and filtersare to be shielded, or grouped in a specialroom or location ventilated by suction.

c Fire Detection and Alarm The propulsion-machinery space is to be provided with a fixed firedetection and alarm system complying with 7.7.1through 7.7.3 of the IMO International Code of Safetyfor High-Speed Craft. This fixed fire detection andalarm system may be combined with other firedetection and alarm system required on board the craft.

d Fire Alarm Call Points Manually operated firealarm call points are to be provided in, and in thepassageways leading to, the propulsion-machineryspace.

4/11.3.19 Monitoring Station in Engineer'sAccommodationThe following is applicable to craft fitted withengineer’s accommodations, if provided.

a General At least one alarm monitoring stationis to be provided in the engineer's public spaces. Eachsuch station is to be provided with alarms for fire, highbilge-water level in the propulsion-machinery space,and summary-alarms for the propulsion and itsassociated machinery Any of the alarm conditions aslisted in Tables 4/11.5 through 4/11.8, as applicable,are to activate the specific machinery summary-alarm.Additionally, alarm monitoring stations through aselector switch are to be provided in each individualengineer's stateroom and arranged so that at least onealarm monitoring station is active at all times.Selective switching is not to be provided for the firealarms. The fire alarm is to be separate and distinctfrom the alarms of any other systems. Fire, high bilge-water level and the specific machinery summary-alarmsare to be audible in the engineer's public spaces andstaterooms until manually silenced at the centralizedcontrol and monitoring station in the propulsion-machinery space.

b Alternative Arrangement The arrangements in4/11.3.19a may be modified to permit the audiblemachinery summary-alarm and high bilge water levelalarm to be silenced locally at the alarm monitoringstations in the engineer's public spaces and stateroomsprovided the associated visual alarm is notextinguished. Also, the arrangements are to be suchthat if the audible alarm is not also silenced manually atthe centralized control and monitoring station in a


reasonable period of time, the system is to activate theengineer's alarm audible in the engineer'saccommodations. The means for silencing locally atthe alarm monitoring stations is not to be provided forfire alarms.

4/11.3.20 CommunicationsFor communication systems associated with propulsioncontrol stations, the requirements in 4/5A8.5.1 areapplicable and is to include the engineer'saccommodations area, if provided.

4/11.3.21 Sea TrialsThe ability to effectively control the propulsion fromthe remote propulsion control station is to bedemonstrated to the satisfaction of the Surveyor duringsea trials or at dockside. These trials are to includepropulsion control transfer, propulsion starting,verification of propulsion control responses, propulsioncontrol power failure and actuation of propulsionemergency stop device. In addition, effective operationof the following is to be demonstrated to thesatisfaction of the Surveyor. With the exception of4/11.3.21e, it is recommended that thesedemonstrations or tests be carried out before sea trialsand are to include simulated failures so that propercorrective actions may be carried out and witnessed bythe Surveyor.

a Control and Monitoring System for PropulsionMachinery and Electrical Power GeneratingMachinery In addition to the verification of requiredcontrol responses, alarms and displays, thisdemonstration is to include the automatic transferringof the required standby vital auxiliary pumps

b Local Control Local control of the propulsionmachinery is to be demonstrated.

c Fire Control and Alarm System In addition tothe verification of required detectors, displays and callpoints and where the fire main is not maintainedpressurized, it is to be demonstrated that at least one ofthe main fire pumps can be started from the station inthe operating compartment.

d Bilge Detection System Automatic starting ofthe propulsion-machinery space bilge pumps is to bedemonstrated.

e Operational Test of Propulsion MachineryAfter the propulsion machinery has been running for atleast 2 hours, the ability to control the machineryfunctions correctly for all loads and engine maneuverswithout any manual intervention in the propulsion-machinery space is to be demonstrated for an additionalperiod of 4 hours. Propulsion machinery or engineresponse to throttle control demands is to be testedduring the trials and after final adjustments todemonstrate that no part of the plant or engine isjeopardized by the rate at which the throttle is movedfrom one extreme position to the other. The loss of

electric power is to be simulated with the main enginerunning.

f Independent Manual Control Independentmanual control of the propulsion machinery is to bedemonstrated. This is to include demonstration ofindependent manual control through the fullmaneuvering range and transfer from automatic control.

4/11.5 Craft Classed with ABCU Symbol

4/11.5.1 GeneralThe requirements in this sub-section apply to craftcapable of operating as ACCU classed craft butbecause of their compact propulsion-machinery spacedesign are not fitted with the means to control thepropulsion and its associated machinery from acentralized location within the propulsion-machineryspace. Except as noted herein, the requirements in4/11.1 through 4/11.3, as applicable, are to becomplied with.

4/11.5.2 Station in the Operating CompartmentControls, alarms and displays as listed in 4/11.3.9 areto be provided on the station in the operatingcompartment. See Table 4/11.3. For craft having non-integrated propulsion machinery, the means forstarting, stopping and transferring vital auxiliary pumps(see 4/11.3.11) are to be fitted at the station in theoperating compartment and may also be fitted in thecentralized station. See 4/11.1.3v for definition ofintegrated propulsion machinery.

4/11.5.3 Centralized Monitoring StationThe requirements in 4/11.3.10 are applicable exceptthat the centralized station need not be provided withpropulsion controls but is to include displays andalarms needed for the monitoring of the propulsionmachinery and associated ship' service systems,electrical power generating machinery, and monitoringof propulsion-machinery space. The monitoring systemis to provide the same degree of equivalency as if thepropulsion-machinery space was manned. See Tables4/11.4 through 4.11.8 for required alarms and displaysto be fitted at this station.

4/11.5.4 CommunicationsCommunications as required in 4/11.3.20 is also toinclude the centralized monitoring station in thepropulsion-machinery space.

4/11.5.5 Sea TrialsIn addition to the trials per 4/11.3.21, successfuloperation of the propulsion machinery is to bedemonstrated with the propulsion-machinery spaceunattended for a period of at least 12 hours.


4/11.7 Craft Less Than 500 GT Having a LengthEqual or Greater Than 20 m (65 ft)

4/11.7.1 GeneralThe requirements contained in this sub-section areintended for craft less than 500 GT having a lengthgreater than 20 m (65 ft). The installation of machineryand monitoring of the propulsion-machinery space insuch craft is to be so arranged that permits the normaloperation of the craft with the propulsion-machineryspace unattended. Craft having a length equal or lessthan 20 m (65 ft) will be specially considered.

Note: ACCU or ABCU class symbol may be granted to craft of <500 GT and a length of 20 m (65 ft)• l • 46 m (150 ft),provided that the applicable requirements in 4/11.1through 4/11.5 of this Section are met.

4/11.7.2 DefinitionsSee 4/11.1.3.

4/11.7.3 Plans to be SubmittedPlans and specifications are to be submitted inaccordance with 4/1.11 for approval and are to includethe following information.

a Machinery arrangement plans showinglocation of control stations in relation to controlledunits;

b Arrangements and details of control consolesincluding front views, installation arrangementstogether with schematic diagrams for all power, controland monitoring systems including their functions; and alist of alarms/displays as required in 4/11.7.8c.

c Type and size of all electrical cables andwiring associated with the control systems includingvoltage rating, service voltage and currents togetherwith overload and short-circuit protection;

d Description of all alarm and emergencytripping arrangements; functional sketches ordescription of all special valves, actuators, sensors andrelays;

e Schematic plans and supporting data of fire-protection and extinguishing systems, including fire-detection and alarm systems and bilge high wateralarms,

f Schematic plans of hydraulic or pneumaticcontrol systems.

4/11.7.4 Electrical Cables and Console WiringIn general, cables are to be used external to theconsoles and they are to be of the marine type inaccordance with the applicable parts of Section 4/5.Cables in accordance with other standards which arenot less effective will be considered. Cables andconsole wiring for control and monitoring are to be ofthe flame-retarding type and are to be stranded exceptthat solid conductors may be used in low-energy circuitwhere they are properly supported and not subject toundue vibration or movements.

4/11.7.5 AlarmsThe alarm system is to be able to indicate more thanone fault at the same time and be so arranged thatacceptance of one fault is not to inhibit another alarm.Audible alarms are to be maintained until they areacknowledged, and visual indication is to remain untilthe fault is corrected.

4/11.7.6 Safety SystemSafety systems are to be of the fail-safe type and are torespond automatically to fault conditions that mayendanger the machinery or safety of the crew. Thisautomatic action is to cause the machinery to take theleast drastic action first, as appropriate, by reducing itsnormal operating output or switching to a stand-bymachinery and last, by stopping it, i.e., disruptingsource of fuel or power supply, etc. However, thepropulsion machinery is to automatically shutdownupon a loss of lubricating oil or an overspeedcondition, and such conditions are to be alarmed.Where arrangements for overriding the shut-down ofthe main propelling machinery are fitted, these are to besuch as to preclude inadvertent activation. Visualmeans shall be provided to show whether or not it hasbeen activated.

4/11.7.7 PropulsionThe requirements in 4/11.3.2b, .2e, .2f, .2g and .2h areapplicable. Additionally, it is to be possible to controlthe propelling machinery locally in the case of failurein any part of the control systems.

4/11.7.8 Propulsion-machinery Spacesa Fire Protection

1 Fire Preventiona Piping for high pressure fuel injection and

return piping on main and auxiliary enginesis to be effectively shielded and secured toprevent fuel or fuel mist from reaching asource of ignition on the engine or itssurroundings. Leakages from such pipingare to be collected in a suitable drain tankprovided with high level alarm audible at theoperating compartment.

b Drip trays for collecting fuel and lubricatingoil are to be fitted below pumps, heaters,burners, tanks not forming part of the craft’sstructure, etc., with connections to a suitabledrain tank with high level alarm audible atthe operating compartment.

c Where daily service fuel oil tanks are filledautomatically or by remote control, meansare to be provided to prevent overflowspillages. Similar consideration is to begiven to other equipment which treatflammable liquids automatically (e.g., fueloil purifiers), which whenever practicableshall be installed in special space reservedfor purifiers and their heaters.


d Where fuel oil daily service tanks or settlingtanks are fitted with heating arrangements, ahigh temperature alarm, audible at theoperating compartment, is to be provided ifthe flashpoint of the fuel oil can beexceeded.

2 Fire Detection A fire detection system is tobe provided for the machinery spaces.

b Protection Against Flooding Bilges inmachinery spaces are to be provided with a high levelalarm in such a way that the accumulation of liquids isdetected at normal angles of trim and heel. The

detection system is to initiate an audible and visualalarm on the operating compartment.

c Operating Compartment In addition toother instrumentation which may be required for thesatisfactory operation of the propulsion machinery andnavigation of the craft, the following controls, alarmsand displays are to be provided at theoperatingcompartment in accordance with Table 1.


TABLE 1Displays and Alarms to be Fitted at the Operating Compartment

(Applicable to craft complying with 4/11.7)

Items Display Alarm

1 Propeller Speed RPM2 Propeller Ahead3 Direction or Astern4 Pitch Pitch5 Generator voltage Volt1

6 Generator current Amps1

The following alarms giving distinctive indication of conditions requiring immediate action and in full view ofthe crew

7 Main engines Overspeed8 Normal electrical supply Loss9 Control power Available Failure

10 Any permanently installed nickel-cadmium battery associated with systems forthe control and monitor of the craft’s propulsion, steering and trim relatedmachinery and propulsion-machinery space

Thermalrunaway

11 Activation of a fire-detection system Light Fire12 Bilge level High

With the exception of items 15 and 21, the following alarms are to be distinct from those referred in items7 through 12 and are to indicate conditions requiring actions to prevent degradation to an unsafe condition

13 L.O. Pressure to main engine & reduction gear Pressure Low14 Engine coolant Temperature High15 Starting air (if applicable) pressure Low16 Normal power supply to the powered directional or trim control devices Failure17 Compass system Failure18 Side, masthead or stern navigation lights Extinction19 Fuel oil tank level Low20 Oil collecting tank(see 4/11.7.8a1b) High or

Overflow21 Fuel oil day tank heater temperature (see 4/11.7.8a1d) High22 Level of contents of any fluid reservoir the contents of which are essential for

normal craft operationLow

23 High pressure fuel line (see 4/11.7.8a1a) Leakage24 Any ventilation fan installed for ventilating spaces in which inflammable

vapours may accumulateFailure

25 Any automatic bilge pump Operation

Emergency Controls to be Fitted at the Operating Compartment and Arranged for Easy Reach of the Crew Members

Items Provision ofDevice

26 Stops for main propulsion and auxiliary machinery x26 Means to disconnect electrical power sources from the normal power distribution system x27 Stops for the machinery-space ventilation blowers and means for closing of openings as per 4/9.5.1 x29 Stops for all fuel-oil pumps and forced-draft blowers x30 Means for starting any one of the fire pumps (inclusive of the one located outside the propulsion-

machinery space) including associated valves necessary to deliver required capacity to the fire mainx

31 Releasing of the fire-fighting media for the propulsion-machinery space This release is to be manualand not initiated automatically by signals from the fire-detecting system.

x

Note:1 As an alternative, these displays may be provided locally.


TABLE 4/11.1Environmental Tests for Propulsion Control and Monitoring Equipment

No TEST PROCEDURE ACCORDING TO[See note 4]

TEST PARAMETERS OTHER INFORMATION

1 VisualInspection

- - - Conformance to drawings, design data;- quality of workmanship and construction.

2 Conditional

The equipment specification - Standard atmosphere conditions.- Temperature: 25 C (77 F) ± 10 C (18 F)- Relative humidity: 60% ± 30%.- Air pressure: .96 bar (.98 Kgf/cm 2.,13.92 Psi) ± .10 bar (.10 Kgf/ cm 2, 1.45Psi)

- Confirmation that operation is inaccordance with the requirements specifiedfor particular automatic systems orequipment;- checking of self-monitoring features;- checking of specified protection againstan access to the memory and effects ofunerroneous use of control elements in thecase of computer systems.

3 Dry heat

IEC Publication 68-2-2 (1974),Amendment No. 1 (1993) and No. 2 (1994)- Test Bb - for non-heat dissipatingequipment.

Temperature: 55 C (131 F) ± 2 C (3.6 F)Duration: 16 hours

orTemperature: 70 C (158 F) ± 2 C (3.6 F)Duration: 2 hours [See note 1]

- Equipment operating during conditioningand testing;- functional test during the last hour of thetest temperature;- functional test after recovery.

IEC Publication 68-2-2 (1974),Amendment No. 1 (1993) and No. 2 (1994)- Test Bd - for heat dissipating equipment.

Temperature: 55 C (131 F) ± 2 C (3.6 F)Duration: 16 hours [See note 1]

orTemperature: 70 C (158 F) ± 2 C (3.6 F)Duration: 2 hours

- Equipment operating during conditioningand testing with cooling system on, ifprovided;- functional test during the last hour at thetest temperature;- functional test after recovery.

4 Damp heat

IEC Publication 68-2-30 (1980),Amendment No. 1 (1985) - Test Db.

Temperature: 55 C (131 F)Humidity: 95%Duration: 2 cycles (12 + 12 hours cycle)

- Measurement of insulation resistance before test;- equipment operating during complete firstcycle and switched off during second cycleexcept for functional test;- functional test during the first 2 hours ofthe first cycle at the test temperature andduring the last 2 hours of the second cycleat the test temperature;- recovery at standard atmosphere condit-ions;- insulation resistance measurements andconditional test.

5 Cold

IEC Publication 68-2-1 (1990),Amendment No. 1 (1993) and No. 2 (1994)- Test Ab - for non-heat dissipatingequipment

Temperature: 5 C (41 F) ± 3 C (5.4 F)Duration: 2 hours

orTemperature:-25 C (-13 F) ± 3 C (5.4 F)Duration: 2 hours [See note 2]

- Initial measurement of insulationresistance;- equipment not operating during conditioning and testing except for functional test;- functional test during last hour at the testtemperature;- insulation resistance measurement and thefunctional test after recovery.

IEC Publication 68-2-1 (1990),Amendment No. 1 (1993) and No. 2 (1994)- Test Ad - for heat dissipating equipment.

Temperature: 5 C (41 F) ± 3 C (5.4 F)Duration: 2 hours [See note 2]

orTemperature:-25 C (-13 F) ± 3 C (5.4 F)Duration: 2 hours

( Cont-)


TABLE 4/11.1 )Environmental Tests for Propulsion Control and Monitoring Equipment



6 Salt mist

IEC Publication 68-2-52 (1984) Test Kb Four spraying periods with a storage of 7days after each.

- Initial measurement of insulationresistance and initial functional test.- equipment not operating duringconditioning of the test specimen;functional test on the 7th day of storageperiod;insulation resistance measurement andoperational; test after recovery.

[See note 3]

7 Insulationresistance

-

Rated Test Minimumsupply voltage insulationvoltage resistance

Before After (V) (V) (M•) (M•)Un •65 2*Un 10 1,0

(min. 24V)Un >65 500 100 10

- Insulation resistance is to be carried outbefore and after: damp heat test , cold testand salt mist test;- between all circuits and earth;- on the supply terminals, whereappropriate.- Un is the rated (nominal) voltage.

8 High voltage -

Rated voltage Un Test voltage(A.C. voltage50 or 60 Hz)

(V) (V) up to 65 2* Un+50066 to 250 1500251 to 500 2000

- Separate circuits are to be tested againsteach other and all circuits connected witheach other tested against earth;- printed circuits with electroniccomponents may be removed during thetest;- period of application of the test voltage: 1minute

9 Electrostaticdischarge

IEC Publication 801-2 (1991). Test voltage: 8KV according to level 3severity standard.

- To simulate electrostatic discharge as mayoccur when persons touch the appliance;- the test is to be confined to the points andsurfaces that can normally be reached bythe operator;- the equipment is to operate during testing;- as a result of the test neither permanent ortransient effects nor damage to theequipment are allowed.

10 Radiatedelectro-

magnetic field

IEC Publication 801-3 (1984). Frequency range: 30 kHz to 500 MHzField strength: 10 V/m- according to severity level 3.

- To simulate electromagnetic fieldsradiated by different transmitter;- the test is to be confined to the applianceexposed to direct radiation by transmittersat their place of installation;- as a result of the test neither permanent ortransient effects nor damage to theequipment are allowed.

11 Conductedinterference

IEC Publication 801-4 (1988) Fast transient(burst)

Test voltage (± 10%) :2 kV on I/O signal data and control lines2kV on power supply

- To simulate interference by electric arcsgenerated when actuating electricalcontacts;- interference effect occurring on the powersupply, as well as at the external wiring ofthe test specimen.- as a result of the test neither permanent ortransient effects nor damage to theequipment are allowed.

( Cont-)


TABLE 4/11.1Environmental Tests for Propulsion Control and Monitoring Equipment

(Applicable to ACCU or ABCU Craft)



11 Conductedinterference

IEC Publication 801-5 (Draft 1990) Surgevoltage immunity

Test voltage:1,0 kV differential mode;2,0 kV common mode

Rise time: 1,2 µsecondsSurge time (50 % value): 50 µseconds

according to severity level 3.Test duration:

not less than 3 min. positive pulse;not less than 3 min. negative pulse;

Repetition rate: 6 pulses/min.

- To simulate interference generated forinstance, by switching on or off high-power inductive consumers;- the test is to be carried out at the powersupply;- as a result of the test neither permanent ortransient effects nor damage to theequipment are allowed.

IEC Publication 1000-4-6 Conducted radiofrequencies interference

Testing signals:1.0 Veff the range between 10 kHz and 50kHz

Modulation: 30%Modulation frequency: 1 kHz(Provisional values applicable tonavigational instrument)

- To simulate electromagnetic fieldscoupled as high frequency into the testspecimen via the connecting lines;- as a result of the test neither permanent ortransient effects nor damage to theequipment are allowed.

12 Vibration

IEC Publication 68-2-6 (1995) Test Fc 2.0 (+3/-0) Hz to 13.2 Hz - amplitude ± 1mm (.039 in).13.2 Hz to 100 Hz- acceleration 0.7 g.For severe vibration conditions such as, e.g.on diesel engines, air compressors, etc.:2.0 Hz to 25 Hz- amplitude ± 1.6 mm(.0630 in).25.0 Hz to 100 Hz- acceleration 4.0 g.

- Duration in case of no resonancecondition 90 minutes at 30 Hz;- duration at each resonance frequency atwhich Q•2 is recorded- 90 minutes;- during the vibration test, operationalconditions are to be demonstrated;- test to be carried out in three mutuallyperpendicular planes;- it is recommended that Q does not exceed5.

13 Inclination

Static 22.5°

Dynamic 22.5°

a) Inclined at an angle of at least 22.5° tothe verticalb) Inclined at least 22.5° on the other sideof the vertical and in the same plane as in(a),c) inclined at an angle of at least 22.5° tothe vertical and in a plane at right angle tothat used in (a),d) Inclined to at least 22.5° on the otherside of the vertical and in the same plane asin (c).Note: The period of testing in each positionshould be sufficient to fully evaluate thebehavior of the equipment.

Using the direction defined in a) to d)above, the equipment is to be rolled to anangle of 22.5° each side of the vertical witha period of 10 seconds.The test in each direction is to be carriedout for not less than 15 minutes.

Notes:

1) Dry heat at 70 C (158 F) is to be carried out for equipment located in a non-air conditioned space. See also 4/11.3.7e2.2) For equipment installed in non-weather protected locations or cold locations test is to be carried out at-25 C (-13 F).See also 4/11.3.7e2 and4/11.3.7e7.3) Salt mist test is to be carried out for equipment installed in weather exposed areas.4) Alternative equivalent testing procedures may be accepted provided the requirements in the other columns are complied with.

.


TABLE 4/11.2Performance Tests for Propulsion Control and Monitoring Equipment


No TEST PROCEDURE ACC. TO TEST PARAMETERS[See note 1]

OTHER INFORMATION

1 Visualinspection

- - - Conformance to drawings, design data,- quality of workmanship andconstruction.

2 Powersupplyfailure

-- 3 interruptions during 5 minutes;- switching-off time 30 seconds each case.

- Verification of the specified action ofthe equipment on loss and restoration ofsupply in accordance with the systemdesign.

3 Powersupply(electric)

-

Combination Voltage Frequencyvariation variationpermanent permanent (%) (%)

1 +10 +52 +10 -53 -10 -54 -10 +5

Combination Voltage Frequencytransient transient 1.5s 5 s (%) (%)

5 +20 +106 -20 -10

Electric battery supply:+30% to -25% for equipment connectedto battery during charging;+20% to -25% for equipment notconnected to the battery during charging.

-

Powersupply(pneumaticandhydraulic)

Pressure: ± 20%.Duration: 15 minutes. -

Notes:1) The conditional test parameters per Table 4/11.1 are applicable.


TABLE 4/11.3

Control Station in the Operating Compartment(Applicable to ACCU or ABCU Classed Craft) 8)

Item Alarm1), 9)

DisplayProvisionsof Deviceon Station

1)

Remarks

A1 Failure or malfunctioning of system x 2), 10)A2 Failure, supply x Main/Standby Automatic transfer 2), 10)

Control A3 Control station in operation Stationand A4 Control transfer switch x

Monitoring System A5 Alarm, disabled (override) Disabled 4)A6 Safety, activation x 3),10)A7 Safety disabled x Disabled 4), 10)

Main PowerSource

B1 Normal electrical supply, loss x

Nickel-cadmiumBattery

C1 Any permanently installed nickel-cadmiumbattery, thermal runaway

x Associated with systems for the control andmonitor of the craft’s propulsion, steering andtrim related machinery and propulsion-machinery space

Supply to Steering& Trim System

D1 Normal power supply to the powereddirectional or trim control devices, failure

x 11)

Compass E1 Compass system, failure x 11)Navigation Lights F1 Side, masthead or stern navigation lights,

extinctionx 11)

Controllable Pitch G1 Start/stop switch for CPP hydraulic motor x If providedPropeller (CPP) G2 CPP hydraulic motor running Running If provided

G3 Automatic starting of required standbypump

x If provided

H1 Remote controls x For each propelling unit and all units, asapplicable

H2 Propeller shaft, speed SpeedPropulsion, H3 Propeller shaft, direction Direction

General H4 Propeller, pitch Pitch For controllable-pitch propellerH5 Prime movers, prolonged operation within

critical speed rangex Visual display may be acceptable

H6 Main engine, overspeed x

PropulsionI1 Starting medium, pressure or level, low x Pressure or

Level 5)

Starting I2 Hazardous condition present x See 4/11.3.2d2I3 Start/stop switch for starting system x Not required for non-reversing engines

Electric Propulsion J1 Propulsion generator load-share overload x See 4/5C2.19.3 &.21.3 and 4/11.3.14Summary-alarms K1 Propulsion and associated machinery,

failurex 6), 7), 11)

Vital AuxiliaryPumps

L1 Start/stop and transfer switches x For ABCU craft having non-integratedpropulsion machinery; it may be combinedwith item T1 below

FO SettlingM1 Level, tank, low x See 4/11.3.16a 11)

and M2 Level, tank, high x See 4/11.3.16b 11)Daily Service Tanks M3 Fuel oil tank, heater temperature, high x See 4/11.3.18b3

FO & LOCollect. Tank

N1 Tank, level high or overflow x See 4/11.3.18b2 11)

High PressureFO System

O1 Leakage x See 4/11.3.18b1 11)

EssentialFluid

Reservoirs

P1 Level of contents of any fluid reservoir thecontents of which are essential for normalcraft operation, low

x 11)

( Cont-)


TABLE 4/11.3

Control Station in the Operating Compartment(Applicable to ACCU or ABCU Classed Craft) 8)

Item Alarm1), 9)

DisplayProvisionsof Deviceon Station

1)

Remarks

Ventilation SystemQ1 Any ventilation fan installed for ventilating

spaces in which inflammable vapours mayaccumulate, failure

x 11)

Fire in MachinerySpace

R1 Fire control x Fire x See 4/11.3.18c 7)

Bilges in Mach. S1 Any automatic bilge pump, operation x 11)Space S1 Level, bilges, high x See 4/11.3.18a1 7)

EmergencyControls

T1 To be arranged for easy reach of the crewmembers

x See 4/11.3.9

Notes:

1) Required actuation device or alarm is denoted by a (x). 2) For each system: control systems, alarm/display systems and safety systems. See 4/11.3.6a1 and 4/11.3.6a2. 3) Actuation of propulsion safeties is to either reduce output or shutdown the propulsion machinery as required. See also 4/11.3.4, 4/11.3.4f and Tables 4/11.5 through 4/11.8. 4) Deactivation means are to be arranged so that such action cannot be done inadvertently. Alternative means to indicate disabling of safety actions oralarms will be considered. 5) This alarm is also to be provided in the machinery space. 6) This summary-alarm is to be activated by any of the alarm conditions as listed in Tables 4/11.5 through 4/11.8. 4/11.3.19. 7) These alarms are also to be alarmed at the engineer's accommodations, see 4/11.3.19. 8) Except for the controls prescribed in item T1 of this Table, the listed instrumentation is also applicable to other remote propulsion control stations iinstalled outside the operating compartment. 9) Provided the audible alarms re-activate automatically after a preset time, audible alarms may be by-passed or de-activated during machinery start-up.10) May be arranged as a summary-alarm (common).11) These alarms are to be distinct from others listed in this Table and are to indicate conditions requiring actions to prevent degradation to an unsafe condition.


TABLE 4/11.4Centralized Control and Monitoring Station


Item Alarm1), 6)

Display Provisionsof Deviceon Station

1)

Remarks

A1 Failure or malfunctioning of system x 2), 5)A2 Failure, supply x Main/Standby Automatic transfer to standby supply 2), 5)A3 Control station in operation StationA4 Control transfer switch x

Control and A5 Control power available, pressure or level Pressure/Level 5)Monitoring System A6 Alarm, disabled (override) Disabled 4), 5)

A7 Safety, activation x 3), 5)A8 Safety disabled x Disabled 4), 5)A9 Safety, disabled (override) switch x See 4/11.3.4f 5)

Main PowerSource

B1 Normal electrical supply, loss x 5)

Nickel-cadmiumBattery

C1 Any permanently installed nickel-cadmiumbattery, thermal runaway

x Associated with systems for the control andmonitor of the craft’s propulsion, steering andtrim related machinery and propulsion-machinery space 5)

Supply to Steering& Trim System

D1 Normal power supply to the powereddirectional or trim control devices, failure

x 5), 7)

Compass E1 Compass system, failure x 5), 7)Navigation Lights F1 Side, masthead or stern navigation lights,

extinctionx 5), 7)

G1 Remote controls xG2 Propeller shaft, speed Speed 5)

Propulsion, G3 Propeller shaft, direction Direction 5)General G4 Propeller, pitch Pitch For controllable-pitch propeller 6)

G5 Prime movers, prolonged operation withincritical speed range

x Visual display may be acceptable 6)

G6 Main engine, overspeed x 5)Propulsion H1 Starting medium, pressure or level, low x Pressure or

Level5)

Starting H2 Hazardous condition present x See 4/11.3.2d2 5)Diesel Propulsion I1 Alarms and displays See Table 4/11.5

Gas turbinePropulsion

J1 Alarms and displays See Table 4/11.8

Electric K1 Alarms and displays See Table 4/11.7Propulsion K1 Propulsion generator load-share overload x See 4/5C2.19.3 &.21.3 and 4/11.3.14Elect. Gen.Machinery

L1 Alarms and displays See Table 4/11.8

FO Settling M1 Level, tank, low x See 4/11.3.16a 5), 7)and M2 Level, tank, high x See 4/11.3.16b 5), 7)

Daily Service Tanks M3 Fuel oil tank, heater temperature, high x See 4/11.3.18b3 5)FO & LO

Collect.TankN1 Tank, level high or overflow x See 4/11.3.18b2 5), 7)

High PressureFO System

O1 Leakage x See 4/11.3.18b1 5), 7)

LO Stern TubeTank

P1 Level, oil, low x 5)

Essential FluidReservoirs

Q1 Level of contents of any fluid reservoir thecontents of which are essential for normalcraft operation, low

x 5), 7)

( Cont-)


TABLE 4/11.4Centralized Control and Monitoring Station


Item Alarm1), 6)

Display Provisionsof Deviceon Station

1)

Remarks

Ventilation SystemR1 Any ventilation fan installed for ventilating

spaces in which inflammable vapours mayaccumulate, failure

x 5), 7)

S1 Level, bilges, high x See 4/11.3.18a1 5)Bilges in S2 Any automatic bilge pump, operation x 5), 7)

Machinery Space S3 Excessive running of bilge pump motor x See 4/11.3.18a2 5)

Notes:

1) Required actuation device or alarm is denoted by a (x).2) For each system: control systems, alarm/display systems and safety systems. See 4/11.3.6a1 and 4/11.3.6a2.3) Actuation of propulsion safeties is to either reduce output or shutdown the propulsion machinery, as required. See 4/11.3.4f and Tables 4/11.5through 4/11.8.4) Deactivation means are to be arranged so that such action cannot be done inadvertently. Alternative means to indicate disabling of safety actions oralarms will be considered.5) For ABCU craft, only these items and the alarms and displays per Tables 4/11.5 through 4/11.8, as applicable, need to be provided on such station.6) Provided the audible alarms re-activate automatically after a preset time, audible alarms may be by-passed or de-activated during machinery start-up.7) These alarms are to be distinct from others listed in this Table and are to indicate conditions requiring actions to prevent degradation to an unsafecondition.


TABLE 4/11.5Monitoring of Propulsion Machinery - Medium/High (Trunk Piston) Speed Diesel Engines

(Applicable to ACCU or ABCU Craft. See also Table 4/11.4)

Item 11) Alarm1)

Display

AutomaticStart of

RequiredStandby

VitalAuxiliary

Pumpwith

Alarm1)

Remarks

A1 Fuel oil after filter (engine inlet), pressure-low

x Pressure x 3)

Fuel Oil System

A2 Fuel oil before injection pumps,temperature or viscosity-low, andFuel oil before injection pumps,temperature or viscosity, high

x 5)

A3 Leakage from high pressure pipes xA4 Fuel oil in daily service tank, level-low x See also 4/11.3.16a.B1 Lube oil to main bearing and thrust

bearing, pressure-lowx Pressure x 3), 4)

B2 Lube oil filter differential, pressure-high x Pressure x 3)Lube Oil System B3 Lube oil inlet, temperature-high x Temp.

B4 Oil mist concentration in crankcase, mist-high

x Automatic engine shutdown 3), 6)

B5 Flow rate cylinder lubricator, flow-low.Each apparatus

x Automatic engine slowdown 2), 10)

Turbo-charger C1 Turbo-charger lube oil inlet, pressure-low x Pressure 7)S. W. Cooling D1 Sea water cooling, pressure-low x Pressure x 3)

Cylinder FreshCooling

E1 Water inlet, pressure-low or flow-low x Press. or flow x Automatic engine slowdown 2), 3)

Water System E2 Water outlet (general), temperature-high x Temp. Automatic engine slowdown 8)E3 Cooling water in expansion tank, level-low x

Air F1 Starting air before main shut-off valve,pressure-low

See item H1 in Table 4/11.4

System F2 Control air, pressure-low x PressureScavenge Air

SystemG1 Scavenge air receiver, temperature-high x

Exhaust Gas H1 Exhaust gas after each cylinder,temperature-high

x Temp. Automatic engine slowdown 2), 9)

System H2 Exhaust gas after each cylinder, deviationfrom average, temperature-high

x 9)

Engine I1 Engine speed SpeedI2 Engine overspeed Automatic engine shutdown ; see also item

G6 in Table 4/11.4 3)Power Supply J1 Control, alarm or safety system, power

supply failurex

Notes:

1) Required alarm or starting of standby pump is denoted by a (x). 2) A common sensor for alarm/display and automatic slowdown is acceptable. 3) Separate sensors are required for: a) alarm/automatic starting of required standby pump, and b) automatic engine shutdown. 4) Automatic engine shutdown is to be alarmed and effected upon loss of oil pressure. . 5) For heavy fuel oil burning engines only. 6) Only for medium speed engines having a power of more than 2250 kW (3000 hp) or a cylinder bore of more than 300 mm (11.8 in.). 7) If without integrated self-contained oil lubrication system. 8) Two separate sensors are required for alarm and slowdown. 9) For engine power > 500 kW/cyl. 10) If necessary for the safe operation of the engine. 11) For ABCU craft having integrated propulsion machinery, exemption from the listed instrumentation and safety provisions will be considered.


TABLE 4/11.6Monitoring of Propulsion Machinery - Gas Turbine

(Applicable to ACCU or ABCU Craft). See also Table 4/11.4)

Item Alarm1)

Display

AutomaticStarting

ofRequiredStandby

VitalAuxiliary

Pump1), 4)

Remarks

A1 Pressure, inlet, low x Pressure x Turbine automatic shutdown 3)Lube Oil A2 Temperature, inlet, high x Temperature

2) A3 Differential pressure, filter, high xA4 Level, tank, low x In gravity tank and sump

Bearings B1 Temperature, high x Main bearingsCooling C1 Pressure or flow, low x Pressure, or

flowMedium C2 Temperature, high x

D1 Pressure or flow, low x Pressure, orflow

Fuel D2 Temperature or viscosity, low x Temperature,or

For heavy fuel

D3 Temperature or viscosity, high x viscosity For heavy fuelE1 Temperature, high x

Exhaust Gas E2 Temperature, high-high x Turbine automatic shutdownE3 Temperature deviation, high x

Turbine F1 Vibration level, high xF2 Vibration level, high-high x Turbine automatic shutdown

Rotor G1 Axial displacement, high xOverspeed H1 Device activated See also item G6 in Table 4/11.4

Notes:

1) Required alarm or starting of standby pump is denoted by a (x). 2) Individual alarms are required where separate systems (e.g., reduction gear, bearing, etc.) are installed. 3) The automatic shutdown is to be effected upon loss of lube oil pressure. 4) For ABCU craft having non-integrated propulsion machinery, starting of required standby pump is to be alarmed.


TABLE 4/11.7Monitoring of Propulsion Machinery Electric


Item Alarm1)

Display Remarks

A1 Pressure, bearing, lube oil inlet, low x Pressure Prime mover automatic shutdownA2 Voltage, off-limits x Voltage To read all phases and at least one bus 2)

Propulsion A3 Frequency, off-limits x FrequencyGenerator A4 Current Current To read all phases 2)

A5 Temperature, stationary windings, high x Temperature To read all phases; for generators >500 kWA6 Transfer of standby generator xB1 Pressure, bearing, lube oil inlet, low x PressureB2 Voltage, armature, off-limits x Voltage To read all phases and at least one busB3 Voltage, field VoltageB4 Frequency, off-limits x Frequency

Propulsion B5 Current, armature Current To read all phasesA.C. Motor B6 Current, field Current For synchronous motors

B7 Ground lights or similar StatusB8 Temperature, stationary windings, high x Temperature To read all phases; for motors >500 kWB9 Motor running Running

B10 Transfer of standby motor xB11 Motor cooling medium temperature, high x Temperature If requiredC1 Pressure, bearing, lube oil inlet, low x Pressure Automatic shutdownC2 Voltage, armature x VoltageC3 Voltage, field VoltageC4 Current, armature Current

Propulsion D.C. C5 Current, field CurrentMotor C6 Ground lights or similar Status

C7 Motor running RunningC8 Failure of on-line motor xC9 Transfer of standby motor x

C10 Motor cooling medium temperature, high x Temperature If requiredD1 Voltage, SCR Voltage

Propulsion D2 Current, SCR CurrentSemi-conductor D3 Overloading conditions, high current x Alarms before protective device is activatedRectifier (SCR) D4 Open/close position for assignment switches Position

D5 SCR cooling medium temperature, high x Temperature If required

Notes:

1) Required alarm is denoted by a (x). 2) For D.C. generators. Additionally, field' voltmeters and ammeters are to be included.


TABLE 4/11. 8Monitoring of Auxiliary Prime-movers and Electrical Generators


Item Alarm1)

Display Remarks

Lube Oil A1 Pressure, lube oil inlet, low x Pressure Automatic engine shutdownA2 Temperature, inlet, high x Temperature

Cooling B1 Pressure or flow, low x Pressure, orflow

Medium B2 Temperature, outlet, high xB3 Level, expansion tank, low x If separate from main system

Diesel C1 Fuel oil leakage from pressure pipe xEngine Fuel Oil C2 Level, in fuel oil daily service tank, low x See also 4/11.3.16a

Crankcase D1 Oil mist concentration, high x Automatic engine shutdown 2)StartingMedium

E1 Pressure or level, low x Pressure, orlevel

Overspeed F1 Device activated x Automatic shutdown. See 4/5C2.17.2 and4/4.11.6 of the “Rules for Building andClassing Steel Vessels”

GE1 Pressure, bearing, lube oil inlet, low x Pressure Prime mover automatic shutdownGE2 Voltage, off-limits x Voltage To read all phases and at least one bus 3)

Electrical GE3 Frequency, off-limits x FrequencyGenerator GE4 Current, high x Current To read all phases 3)

GE5 Transfer of standby generator x

Notes: 1) Required alarm is denoted by a (x). 2) For engines having a power of more than 2250 kW (3000 Hp) or having a cylinder bore over 300 mm (11.8 in.). 3) For D.C. generation. Additionally, field' voltmeters and ammeters are to be included.

PART 5

Contents

Specialized Craft and Services

SECTION

1 Craft Intended to Carry Passengers

Appendix5/A Guidelines for Accommodation Design of Passenger Craft

PART 5 SECTION 1| 1 Craft Intended to Carry Passengers

PART 5 SECTION 1

Craft Intended to Carry Passengers

5/1.1 General

5/1.1.1 ClassificationIn accordance with 1/1.3.2, either theclassification of !!!!A1 HSC Passenger Craft (A)or !!!!A1 HSC Passenger Craft (B) is to beassigned to craft designed and specifically fittedfor the carriage of passengers and built to theapplicable requirements of this section and otherrelevant sections of the Guide. In addition, thecraft is to have a Safety Certificate for High-Speed Craft from the Administration of registryor its agent evidencing the craft compliance withthe requirements of the International Code forSafety for High-Speed Craft (IMO HSC Code).

5/1.1.2 ApplicationThese requirements are intended to apply to acraft of Category A or Category B of theInternational Code for Safety for High-SpeedCraft, carrying more than twelve passengers onan international voyage.

5/1.1.3 ScopeThis section is intended to cover the additionalhull construction, accommodation arrangement,machinery and safety equipment required to classa craft as a passenger craft. These requirementsare applicable to those features that arepermanent in nature and can be verified by planreview, calculation, physical survey or any othermeans. This Guide does not address therequirements for Life Saving Appliances andArrangements (Chapter 8), NavigationalEquipment (Chapter 13), Radio Communications(Chapter 14), and Operational Requirements(Chapter 18) found in the International Code forSafety for High-Speed Craft, which are not acondition for classification.

For a passenger craft intended forinternational voyage which is beyond the scopeof the International Code for Safety for High-Speed Craft, the arrangements and scantlings areto comply with the requirements of Section 5/5of Rules for Building and Classing Steel Vessels.

For a passenger craft intended for service indomestic waters, the additional hull construction,accommodation arrangement, machinery andsafety equipment requirements in this sectionmay be replaced with the Regulations of the flagAdministration for a craft intended solely forservice in domestic waters.

5/1.1.4 Safety Certificate for High-SpeedCraft

Where authorized by the Administration ofcountry signatory to the International Conventionfor the Safety of Life at Sea, 1974 as amended,and upon request of the owners of a classed craftor one intended to be classed, the Bureau willreview the plans, data, etc., and survey the craftfor compliance with the requirements of theInternational Code for Safety for High-SpeedCraft and issue a Safety Certificate for High-Speed Craft, prescribed in the Convention onbehalf of the Administration.

5/1.1.5 Independent ReviewWhen the Safety Certificate for High-Speed Craftis issued by an Administration or its agent otherthan the Bureau, the Bureau when requested bythe owner, shipyard, or designers, will conductan independent review of any of the following:

Subdivisions and StabilityTrim and Stability BookletInclining ExperimentStructural Fire ProtectionLife-Saving Appliances and Arrangements

Fees for such independent reviews will becharged to the owner when the review isrequested.

5/1.1.6 Administration ApprovalIn general, the approval of material for use inaccommodation, safety equipment, life-savingappliances, etc. is a function of theAdministration. When the craft is issued aPassenger Ship Safety Certificate by theAdministration or its agent other than the Bureau,such certificate will be accepted as evidence thatthe Administration has approved the material,safety equipment, life-saving appliances, etc.

On other passenger craft, the designer orbuilder will submit evidence that theAdministration has approved the material, safetyequipment, life-saving appliances, etc. forBureau acceptance on craft building to class.


When given specific instructions from theAdministration, the Bureau may approve andaccept the material, equipment, life-savingappliances, etc. fitted on the craft.

5/1.3 Definitions

5/1.3.1 GeneralFor definitions of terms used in this section andnot shown below, reference is to be made to thedefinitions in the various Chapters in theInternational Code of Safety for High-SpeedCraft. (Abbreviated: IMO HSC Code).

5/1.3.2 AdministrationAdministration means the Government of theState whose flag the craft is entitled to fly.

5/1.3.3 Category A CraftAny high-speed passenger craft carrying notmore than 450 passengers and operating on aroute where it has been demonstrated to thesatisfaction of the flag and port States that thereis a high probability that, in the event of anevacuation at any point of the route, allpassengers and crew can be rescued safely withinthe least of : a) the time to prevent persons insurvival craft from exposure causinghypothermia in the worst intended conditions, b)the time appropriate with respect toenvironmental conditions and geographicalfeatures of the route, or c) 4 hours.

5/1.3.4 Category B CraftAny high-speed passenger craft, other than acategory A craft, with machinery and safetysystems arranged such that, in the event ofdamage disabling any essential machinery andsafety systems in one compartment, the craftretains the capability to navigate safely.

5/1.3.5 Crew AccommodationCrew accommodation are those spaces allocatedfor the use of the crew, and include cabins, sickbays, offices, lavatories, lounges and similarspaces.

5/1.3.6 PassengerA passenger is every person other than, a) themaster and members of the crew or otherpersons employed or engaged in any capacity onboard a craft on the business of that craft and b) achild under one year of age.

5/1.3.7 Public SpacePublic spaces are those spaces allocated for thepassengers and include bars, kiosks, smokerooms, main seating areas, lounges, diningrooms, recreation rooms, lobbies, lavatories andsimilar permanently enclosed spaces allocatedfor passengers.

5/1.5 Intact StabilityThe intact stability for passenger craft, in thedisplacement mode, in the transient mode and inthe non-displacement mode are to comply with arecognized standard. The submission ofevidence showing approval by an Administrationwill be acceptable. Alternatively, upon requestthe review will be performed by the Bureau forcompliance with the applicable requirements ofIMO HSC Code.

5/1.7 Subdivision and Damage StabilityWhen the craft is issued a Safety Certificate forHigh-Speed Craft by the Administration or itsagent other than the Bureau, such certificate willbe accepted as evidence of compliance with thesubdivision and stability requirements ofChapter 2.6 of IMO HSC Code. On all otherpassenger craft, when authorized by anAdministration and requested by the Owner, theBureau will review the data on the subdivisionand stability for compliance with IMO HSCCode on behalf of the Administration. However,also see 5/1.1.5.

5/1.9 Inclining Experiment and StabilityInformation

When the craft is issued a Safety Certificate forHigh-Speed Craft by the Administration or itsagent other than the Bureau, such certificate willbe accepted as evidence of compliance with therequirement for an inclining experiment andstability information of Chapter 2.7 of IMO HSCCode. On all other passenger craft, whenauthorized by an Administration and requestedby the Owner, the Bureau will review theinclining experiment and stability information forcompliance with IMO HSC Code on behalf ofthe Administration. However, also see 5/1.1.5.

5/1.11 ConstructionThe scantlings and arrangements of the hullstructure are to be in accordance with theapplicable requirements of Part 3.


5/1.13 Accommodation Space DesignPassenger and crew accommodation spaces areto be designed and arranged so that the occupantsare protected from unfavorable environmentalconditions, and the risk of injury to occupantsduring normal and emergency conditions isminimized. Spaces accessible to passengers arenot to contain controls, electrical equipment,high-temperature parts and pipelines, rotatingassemblies, or other items from which injury topassengers could result, unless such items areadequately shielded, isolated, or otherwiseprotected. The design and location of public spaces andcrew accommodation may be in accordance withthe requirements in Appendix 5/A “Guidelinesfor Accommodation Design of Passenger Craft”unless the flag Administration has specificrequirements in this respect.

5/1.15 Emergency Source of Power

The emergency source of electrical power is tocomply with 4/5A3 except as modified below.

5/1.15.1 Alternative to Emergency Source ofPower

Where the main source of electrical power islocated in two or more compartments which arenot contiguous, each of which has its own self-contained systems, including power distributionand control systems, completely independent ofeach other and such that a fire or other casualtyin any one of the spaces will not affect the powerdistribution from the others, or to the servicesrequired by 5/1.15.3a or 5/1.15.3b, therequirements of 4/5A.3.1, 4/5A.3.1.1 and4/5A.3.5.4 may be considered satisfied withoutan additional emergency source of electricalpower, provided that:

a There is at least one generating set,meeting the inclination requirements of 4/1.21and of sufficient capacity to meet therequirements of 5/1.15.3a or 5/1.15.3b in each ofat least two non-contiguous spaces;

b The arrangements required by 5/1.15.1a ineach such space are equivalent to those requiredby 4/5A3.5.2, 4/5A3.9 and 4/5A3.15 so that asource of electrical power is available at all timesto the services required by 5/1.15.3a or5/1.15.3b; and

c The generator sets referred to in 5/1.15.1aand their self-contained systems are installedsuch that one of them remains operable afterdamage or flooding in any one compartment.

5/1.15.3 Emergency Servicesa Category A Craft The emergency source ofpower is to be capable of supplyingsimultaneously the following services:

1 For a period of 5 h, emergency lighting:a At the stowage positions of life-savingappliances;b At all escape routes such as alleyways,stairways, exits from accommodation andservice spaces, embarkation points, etc;c In the public spaces;d In the machinery spaces and mainemergency generating spaces, including theircontrol positions;e In control stations;f At the stowage positions for fireman'soutfits; andg At the steering gear;

2 For a period of 5 h:a Main navigation lights, except for "notunder command" lights;b Electrical internal communicationequipment for announcements for passengersand crew required during evacuation;c Fire-detection and general alarm systemand manual fire alarms; andd Remote control devices of fire-extinguishing systems, if electrical;

3 For a period of 4 h of intermittentoperation:

a The daylight signaling lamps, if they haveno independent supply from their ownaccumulator battery; andb The craft's whistle, if electrically driven;

4 For a period of 5 h:a Craft radio facilities and other loads as setout in 14.12.2 of the IMO’s InternationalCode of Safety for High-speed Craft; andb Emergency control monitoring systems asrequired by 4/11.3.6a2a

5 For a period of 12 h, the "not undercommand" lights; and6 For a period of 10 min continuousoperation, steering gear to comply with4/5A6.5 if powered from the emergencysource.

b Category B Craft The electrical poweravailable is to be sufficient to supply all thoseservices that are essential for safety in anemergency, due regard being paid to suchservices as may have to be operatedsimultaneously. The emergency source ofelectrical power is to be capable, having regardto starting currents and the transitory nature of


certain loads, of supplying simultaneously atleast the following services for the periodsspecified hereinafter, if they depend upon anelectrical source for their operation:

1 For a period of 12 h, emergency lighting:a At the stowage positions of life-savingappliances;b At all escape routes, such as alleyways,stairways, exits from accommodation andservice spaces, embarkation points, etc.;c In the passenger compartments;d In the machinery spaces and mainemergency generating spaces, including theircontrol positions;e In control stations;f At the stowage positions for fireman'soutfits; andg At the steering gear;

2 For a period of 12 h:a The navigation lights and other lightsrequired by the International Regulations forPreventing Collisions at Sea in force;b Electrical internal communicationequipment for announcements for passengersand crew required during evacuation;c Fire-detection and general alarm systemand manual fire alarms; andd Remote control devices of fire-extinguishing systems, if electrical;

3 For a period of 4 h of intermittentoperation:

a The daylight signaling lamps, if they haveno independent supply from their ownaccumulator battery; andb The craft's whistle, if electrically driven;

4 For a period of 12 h:a The navigational equipment as requiredby Chapter 13 of the IMO’s InternationalCode of Safety for High-speed Craft. Wheresuch provision is unreasonable orimpracticable, the Administration may waivethis requirement for craft of less than 5,000GT;b Essential electrically powered instrumentsand controls for propulsion machinery, ifalternate sources of power are not availablefor such devices;c One of the fire pumps required by 4/9.3;d The sprinkler pump and drencher pump, iffitted;e The emergency bilge pump and all theequipment essential for the operation ofelectrically powered remote controlled bilgevalves as required by 5/1.21; and

f Craft radio facilities and other loads as setout in 14.12.2 of the IMO’s InternationalCode of Safety for High-speed Craft;

5 For a period of 30 min, any watertightdoors, required by Section 3/3, to be power-operated, together with their indicators andwarning signals;6 For a period of 10 min continuousoperation, steering gear to comply with4/5A6.5 if powered from the emergencysource.

5/1.15.5 Transitional Source of PowerThe transitional source of emergency electricalpower required by 4/5A3.5.2b2 may consist of anaccumulator battery suitably located for use in anemergency which is to operate withoutrecharging while maintaining the voltage of thebattery throughout the discharge period within12% above or below its nominal voltage and beof sufficient capacity and so arranged as tosupply automatically in the event of failure ofeither the main or emergency source of electricalpower at least the following services, if thedepend upon an electrical source for theiroperation:

a For a period of 30 min, the load specified in5/1.15.3a1 through .15.3a3 or in 5/1.15.3b1through .15.3b3; andb With respect to the watertight doors:

1 Power to operate the watertight doors, butnot necessarily simultaneously, unless anindependent temporary source of storedenergy is provided. The power source shouldhave sufficient capacity to operate each doorat least three times, i.e. closed - open -closed, against an adverse list of 15°; and2 Power to the control, indication and alarmcircuits for the watertight doors for half anhour.

The above requirements may be consideredsatisfied without the installation of a transitionalsource of emergency electrical power if each ofthe services required by that paragraph hasindependent supplies, for the period specified,from accumulator batteries suitably located foruse in an emergency. The supply of emergencypower to the instruments and controls of thepropulsion and direction systems should beuninterruptible.


5/1.15.7 Supplemental Emergency Lightingfor Craft Having Special-categorySpaces

In addition to the emergency lighting required by5/1.15.3a1, 5/1.15.3b1 and 5/1.15.5a on everycraft with special-category spaces:

a All passenger public spaces* and alleywaysare to be provided with supplementary electriclighting that can operate for at least 3 h when allother sources of electric power have failed andunder any condition of heel. The illuminationprovided is to be such that the approach to themeans of escape can be readily seen. The sourceof power for the supplementary lighting is toconsist of accumulator batteries located withinthe lighting units that are continuously charged,where practicable, from the emergencyswitchboard. Alternatively, any other means oflighting, which is at least as effective, may beaccepted by the Administration.

The supplementary lighting is to be such thatany failure of the lamp will be immediatelyapparent. Any accumulator battery provided isto be replaced at intervals having regard to thespecified service life in the ambient conditionthat it is subject to in service; and

b A portable rechargeable battery-operatedlamp is to be provided in every crew spacealleyway, recreational space and every workingspace which is normally occupied unlesssupplementary emergency lighting, as requiredby 5/1.15.7a, is provided.

* In category A craft having limited public spaces,emergency lighting fittings of the type described in5/1.15.7a as meeting the requirements of 5/1.15.3a1and 5/1.15.5a may be accepted, provided that anadequate standard of safety is attained.

5/1.15.9 Arrangements for Periodic TestingProvision is to be made for the periodic testing ofthe complete emergency system, including theemergency consumers required by 5/1.15.3a or5/1.15.3b and 5/1.15.5, and is to include thetesting of automatic starting arrangements.

5/1.15.11 DistributionDistribution systems are to be so arranged thatfire in any main vertical zone will not interferewith services essential for safety in any othersuch zone. This requirement will be met if mainand emergency feeders passing through any suchzone are separated both vertically andhorizontally as widely as is practicable.

5/1.17 Fire Safety MeasuresThe requirements specified in 3/24.3 areapplicable. In addition, the arrangement ofspaces is to be as follows:

a For category A craft, a single public spaceis acceptable.

b For category B craft, public spaces are tobe divided into zones according to the following:

1 Passenger spaces are to be dividedinto at least two zones and the meanlength of each zone is to be less than40 m.

2 For the occupants of each zone thereshould be an alternative safe area towhich it is possible to escape in caseof fire. The alternative safe area is tobe separated from other passengerzones by smoke-tight divisions of non-combustible materials or fire-restricting materials extending fromdeck to deck. The alternative safearea can be another passenger zoneprovided the additional number ofpassengers may be accommodated inan emergency.

3 The alternative safe area is to belocated adjacent to the passenger zoneit is intended to serve. There shouldbe at least two exits from eachpassenger zone, located as far awayfrom each other as possible, leading tothe alternative safe area. Escaperoutes should be provided to enableall passengers and crew to be safelyevacuated from the alternative safearea.

c Control stations, stowage positions of life-saving appliances, escape routes and places ofembarkation into survival craft are not to belocated adjacent to any area of major or ofmoderate fire hazard.

5/1.19 Fire Fighting

5/1.19.1 GeneralThe requirements in Section 4/9 applicable forcargo craft of 500 gross tons and above are to beapplied for all passenger craft, regardless of thegross tonnage. The following requirements alsoapply.


5/1.19.2 Fixed Sprinkler SystemPublic spaces, service spaces, storage roomsother than those containing flammable liquids,and similar spaces are to be protected by a fixedsprinkler system. Manually operated sprinklersystems are to be divided into sections ofappropriate size, and the valves for each section,the means to start the sprinkler pump(s) andalarms are to be operable from two spacesseparated as widely as possible, one of which isto be a continuously manned control station. Incategory B craft, no section of the system is toserve more than one of the zones required in5/1.17.1.

Plans of the system are to be displayed ateach operating station.

Suitable alternatives may be accepted in lieuof a fixed sprinkler system provided thealternative is acceptable to the Administration.

5/1.19.3 Fireman's Outfitsa Category A Craft The fireman’s outfits in

4/9.9 are not required for Category A Craft.b Category B Craft In addition to the two

fireman's outfits required by 4/9.9, there are to betwo more fireman’s outfits for every 80m (265ft), or part thereof, of the aggregate of the lengthsof all passenger spaces and service spaces on thedeck which includes such spaces. If there ismore than one such deck, the deck which has thelargest aggregate of such lengths is to be used fordetermining the number of additional fireman’soutfits to be carried. Each fireman’s outfit is toconsist of the items in 4/9.9. Also, one water fogapplicator is to be provided for each pair ofbreathing apparatus. The water fog applicator isto be stored adjacent to the breathingapparatuses.

5/1.21 Bilge System

5/1.21.1 GeneralThe bilge system is to comply with 4/6.33through 4/6.42 except as modified below.Suitable arrangements are to be provided for thedrainage and discharge of water which may bedischarged by the fixed sprinkler system in5/1.19.2.

5/1.21.2 Number of Fixed Bilge Pumpsa Monohull Craft Each category B

monohull craft is to be provided with three powerbilge pumps connected to the bilge main. Eachcategory A craft is to be provided with at leasttwo power bilge pumps connected to the bilge

main. One of the pumps in either case may bedriven by the propulsion machinery.

b Multihull Craft On multihull craft, eachhull is to be provided with at least two bilgepumps.

5/1.21.3 Arrangement of Fixed Bilge PumpsThe bilge system is to be arranged such that atleast one power bilge pump will be available foruse in all flooding conditions which the craft isrequired to withstand as follows:

a One of the bilge pumps is to be anemergency pump of a reliable submersible typeconnected to an emergency source of power; or

b The bilge pumps and their sources ofpower are to be distributed throughout the lengthcraft so that at least one pump in an undamagedcompartment will be available.

5/1.21.4 Submersible Bilge PumpsAs an alternative to 5/1.21.2 and 5/1.21.3, anarrangement utilizing submersible pumps may beutilized. See 4/6.41.

5/1.21.5 Manifolds, Cocks and ValvesManifolds, cocks and valves in connection withthe bilge pumping system are to be so arrangedthat, in the event of flooding, one of the bilgepumps may be operative in any compartment. Inaddition, damage to a pump or its pipeconnection to the bilge main is not to make thebilge system inoperable. When, in addition tothe main bilge pumping system, an emergencybilge pumping system is provided, it is to beindependent of the main system and so arrangedthat a pump is capable of operating in anycompartment under the specified floodingconditions. In that case, only the valvesnecessary for the operation of the emergencysystem need be capable of being operated fromabove the bulkhead deck.

All cocks and valves referred to above whichcan be operated from above the bulkhead deckare to have their controls at their place ofoperation clearly marked and are to be providedwith means to indicate whether they are open orclosed.

5/1.23 Ro/Ro Craft

Craft which are intended for carrying motorvehicles in addition to passengers are to complywith the following requirements.


5/1.23.1 Definition of SpacesVehicles may be carried in open vehicle spacesor in special category spaces, which are definedas follows:

a Open Vehicle Spaces Open vehiclespaces are spaces intended for the carriage ofmotor vehicles with fuel in their tanks for theirown propulsion, to which passengers haveaccess, that are either open at both ends or openat one end and provided with adequate naturalventilation effective over their entire lengththrough permanent openings in the side platingor deckhead or from above.

b Special Category Spaces Specialcategory spaces are those enclosed spacesintended for the carriage of motor vehicles withfuel in their tanks for their own propulsion, intoand from which such vehicles can be driven, andto which passengers have access, includingspaces intended for the carriage of cargovehicles.

5/1.23.2 Electrical Equipment and VentilationElectrical equipment and ventilation for specialcategory spaces are to be in accordance with4/5E1.

5/1.23.3 Fire Detection and Fire AlarmSystems

Open vehicle spaces and special category spacesare to be provided with fire detection and firealarms system complying with 4/9.23.

5/1.23.4 Fire Extinguishing SystemEach special category space is to be fitted withan approved manually-operated fixed pressurewater spraying system. Other types of fireextinguishing systems may be consideredprovided that they have been shown by full-scale

test in conditions simulating a flowing petrol firein a special category space to be not lesseffective in controlling fires likely to occur insuch a space.

5/1.23.5 Fire Extinguishing EquipmentEach special category space is to be providedwith the following fire extinguishing equipment.

a at least three water fog applicators.b one portable foam applicator unit

consisting of an air-foam nozzle of an inductortype capable of being connected to the fire mainby a fire hose, together with a portable tankcontaining 20 liters (5 U.S. gallons) of foam-making liquid and one spare tank. The nozzle isto be capable of producing effective foamsuitable for extinguishing an oil fire at the rate ofat least 1.5 m3/min. (53 ft3/min.). Each crafthaving special category spaces is be providedwith at least two portable foam applicator unitsas a minimum.

c portable fire extinguishers located so thatno point in the space is more than 15 m (50 ft)from an extinguisher, provided that at least oneportable extinguisher is located at each access tothe space.

5/1.23.6 Scuppers, Bilge Pumping andDrainage

In order to prevent a serious loss of stabilitywhich could result due to large quantities ofwater accumulating on the vehicle deck(s) fromoperation of the fixed water spraying system in5/1.23.5, scuppers are to be fitted to directlydischarge the water overboard. Alternatively,pumping and drainage arrangements may beprovided additional to the requirements in5/1.21.

PART 5 Appendix A|1 Guidelines for Accommodation Design of Passenger Craft

PART 5 APPENDIX A

Guidelines for Accommodation Design ofPassenger Craft

Note:This Appendix is prepared to give guidelines to users of the Guide to design, build and operate craft intended tocarry passengers on International voyages. It should be noted that any interpretations to the International Codeof Safety for High-Speed Craft in this respect issued by the flag Administration govern the guidelines in thisAppendix.

5/A.1 GeneralFor passenger craft, superimposed verticalaccelerations above 1.0g at the longitudinal center ofgravity should be avoided unless special precautionsare taken with respect to passenger safety.

5/A.2 Design Acceleration LevelsPassenger craft are to be designed for the collisionload with respect to the safety in, and escape from,the public spaces, crew accommodation and escaperoutes, including in way of life-saving appliances, andemergency source of power. The size and type ofcraft together with speed, displacement and buildingmaterial are to be taken into consideration when thecollision load is determined. The collision designcondition is to be based on a head on collision atoperational speed with a vertical rock with maximum2 m height above the waterline. Unless any specificdata of collision energy are available in the process ofdesign, the following may be used for assessment ofcollision deceleration. Where the deceleration of thecraft is determined by carrying out a collision loadanalysis of the craft in accordance with theseassumptions, that value may be used as gcoll.

1 Monohulls

gcoll = 12. kP

∆wheregcoll = collision deceleration in g’sk = 0.102 (1.0, 1.0)

P = ( )k EC MCH L1

23 kN (tf, Ltf),

but not less than ( )k MC C k dL H c2 3 2+kN (tf, Ltf)

k1 = 460 (100, 66.9)k2 = 9000 (918, 903)

k3 = 1 (1, 0.305)M = 0.95 for mild steel

= 1.3 for higher tensile steel= 1.0 for aluminum alloy= 0.8 for fiber reinforced plastic

CL =( )165

245 803 3

0 4++

k L k Lc c

.

CH =( )k d f k D

k Dc c

c

3 3

3

2 2

2

+ +

Lc = overall length of the underwater watertightenvelope of the rigid hull, excludingappendages, at or below the design waterlinein the displacement mode with no lift orpropulsion machinery active.

Dc = depth of the craft measured at the middle ofL from the underside of the keel to the top ofthe effective hull girder in meters (feet)

dc = bouyancy tank clearance to skirt tip (m, (ft),(negative)) for air-cushion vehicles; liftedclearance from keel to water surface (m, (ft)(negative)) for hydrofoils; and draft of thecraft measured at the middle of L from theunderside of the keel to the design loadwaterline in m (ft) for all other craft.

f = 0 when (dc + 2) < Dc SI or MKS units,[(dc + 6.6) < Dc U.S. units]

= 1 when (dc + 2) ≥ Dc SI or MKS units,[(dc + 6.6) ≥ Dc U.S. units]

E = kinetic energy of the craft, 0.132∆V2 kN-m(0.0135∆V2 tf-m, 0.0442∆V2 Ltf-ft.)

∆ = average craft displacement taken as the meanof the lightweight and the maximumoperational displacement in tonnes (longtons)

V = operational speed of the craft in knots.g = 9.81 (1.0, 32.2)

PART 5 Appendix A|2 Guidelines for Accommodation Design of Passenger Craft

2 Catamarans and SES Craft Catamarans andSES craft may use the same equation as given in a forgcoll with the following exceptions:f = 0 for T+2<Dc-HT SI or MKS units,

(T+6.6<Dc-HT U.S. units)= 1 for Dc>(T+2)≥Dc-HT SI or MKS units,

(Dc>(T+6.6)≥Dc-HT U.S. units)= 2 for T+2≥Dc SI or MKS units,

(T+6.6≥Dc U.S. units)T = lifted clearance from the keel to the water

surface in m (ft.), taken as negativeHT = minimum height from tunnel or wet deck

bottom to the top of the effective hull girderin meters (feet)

3 Air Cushion VehiclesAir cushion vehicles may use the same equation asgiven in a for gcoll with the following exceptions:f = 1 for HT > 2 SI or MKS units,

(HT > 6.6 US units)= 2 for HT ≤ 2 SI or MKS units,

(HT ≤ 6.6 US units)

HT is as defined in 5/A.2.24 Hydrofoils Hydrofoils may use the same

equation as given in a for gcoll, however gcoll is not to

be taken less than kF

∆ where

F = failure load of bow foil assembly applied atthe operational waterline in kN (tf, Ltf)

k and ∆ are as defined in 5/A.2.1

5/A. 3 Accommodation Design1 Location of Public Spaces Public spaces are

not to be located within a distance of 0 0132 2. V

gcoll

meters 0 0434 2. V

gcoll

ft

of the extreme forward end

of the top of the effective hull girder of the craft,where the terms V and gcoll are as defined in 5/A.2.For the purpose of this requirement, gcoll is not to betaken as greater than 12, and need not be taken as lessthan 3.

2 Accommodation RequirementsAccommodations are to be as required by Table5/A.1, and are to be designed to a recognizedstandard.

3 Foundations Calculations are to be submittedindicating that foundations for large masses such asmain engines, auxiliary engines, lift fans,transmissions and electrical equipment can withstandthe collision design acceleration, gcoll, as given in5/A.2 without fracturing.

Table 5/A. 1 Accommodation Requirements

gcoll

< 3 3 ≤ gcoll ≤ 12 > 12Seat Seatback

RequirementsLow or highseatback

High seatback with protectivedeformation and padding

High seatback with protectivedeformation and padding

SeatingDirection

No restrictions Forward or backward Forward or backward

Sofas Sofas allowed Not allowed as seats Not allowedSeat Belts Not required Lap belt required in seats

with no protective structureforward

Three point belt or belt withshoulder harness in forwardfacing seats

Tables No restrictions Protective features anddynamic testing required

Not allowed

Projectingobjects

Padding required Padding required Padding required and is to bespecially approved.

Kiosks,bars, etc.

No restrictions Only on aft side of bulkheadsor specially approved

Specially approved

Baggage No restrictions Protection required forward Protection required forwardand is to be speciallyapproved

Largemasses

To be restrainedand positioned

To be restrained andpositioned

To be restrained andpositioned and to be speciallyapproved

Guide for Building and Classing High Speed Craft

Documents

Transcript of Guide for Building and Classing High Speed Craft