DNV Standard for Certification 2.21 Craft

DET NORSKE VERITAS

STANDARD FOR CERTIFICATIONNo. 2.21

CRAFT

APRIL 2010

FOREWORDDET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life, prop-erty and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification and consultancyservices relating to quality of ships, offshore units and installations, and onshore industries worldwide, and carries out researchin relation to these functions.Standards for CertificationStandards for Certification (previously Certification Notes) are publications that contain principles, acceptance criteria and prac-tical information related to the Society's consideration of objects, personnel, organisations, services and operations. Standardsfor Certification also apply as the basis for the issue of certificates and/or declarations that may not necessarily be related to clas-sification. A list of Standards for Certification is found in the latest edition of Pt.0 Ch.1 of the “Rules for Classification of Ships” and the“Rules for Classification of High Speed, Light Craft and Naval Surface Craft”.The list of Standards for Certification is also included in the current “Classification Services – Publications” issued by the Society,which is available on request. All publications may be ordered from the Society’s Web site http://webshop.dnv.com/global/.The Society reserves the exclusive right to interpret, decide equivalence or make exemptions to this Standard for Certification.Amendments and Corrections This document is valid until superseded by a new revision or withdrawn. Minor amendments and corrections will be publishedin a separate document normally updated twice per year (April and October). For a complete listing of the changes, see the “Amendments and Corrections” document located at: http://webshop.dnv.com/global/, under category “Standards for Certification”.The electronic web-versions of the DNV Standards for Certification will be regularly updated to include these amendments andcorrections.

Comments may be sent by e-mail to [email protected] information about DNV and the Society's services is found at the Web site http://www.dnv.com

© Det Norske VeritasComputer Typesetting (Adobe FrameMaker) by Det Norske Veritas

If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas, then Det Norske Veritas shall pay compensation to such personfor his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compen-sation shall never exceed USD 2 million.In this provision "Det Norske Veritas" shall mean the Foundation Det Norske Veritas as well as all its subsidiaries, directors, officers, employees, agents and any other acting on behalf of DetNorske Veritas.

DET NORSKE VERITAS

Standard for Certification - No. 2.21, April 2010

Main changesThis Standard shall replace and will enter into force from theday of publication.

The main changes are:

— Ch.1 Sec.2, Certification Systematics and Procedures,have been re-written, and the latter moved to a new Sec.3Procedures.

— The work process is adjusted to follow the standard CMC-process as far as practically possible. This change entailsissuance of ordinary Type Approval Certificate for Craft.

— TAP-certificates will be published through the DNV Ex-change.

— Certification "plate" for work boats will no longer be of-fered.


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CONTENTS

A. Main changes .........................................................................3

CH. 1 GENERAL REGULATIONS...............................7

Sec. 1 Introduction........................................................... 9

A. Scope ......................................................................................9

B. Requirements ..........................................................................9

C. Recreational Craft...................................................................9

Sec. 2 Certification systematics .................................... 10

A. General..................................................................................10

B. Certification - Procedures.....................................................10

C. Technical documentation......................................................10

D. Certificates............................................................................10

Sec. 3 Procedures ........................................................... 11

A. One-off craft (Module G) .....................................................11

B. Series of craft (Module B and F or D)..................................11

Sec. 4 Testing/Sea Trials ............................................... 13

A. General..................................................................................13

Sec. 5 Definitions............................................................ 14

CH. 2 ARRANGEMENT, STABILITY AND SAFETY................................................................15

Sec. 1 Arrangement ....................................................... 17

A. General..................................................................................17

B. Accommodation....................................................................17

C. Wheelhouse ..........................................................................17

Sec. 2 Stability, Water- and Weathertight Integrity .............................................................. 19

A. General .................................................................................19

B. Freeboard ..............................................................................19

C. Stability – Decked craft ........................................................19

D. Stability – Open craft............................................................19

E. Stability - Open craft with buoyancy....................................20

F. Freeing ports and drainage ..................................................20

G. Weathertight integrity...........................................................20

H. Buoyancy elements...............................................................21

I. Ballast ................................................................................... 21

Sec. 3 Safety of Personnel ............................................ 22

A. Safety Plan ...........................................................................22

B. Railings, Ladders, Handholds, Decks ..................................22

C. Operation of deck gear .........................................................22

CH. 3 MATERIALS AND MANUFACTURING........23

Sec. 1 General Requirements........................................ 25

A. Metallic materials .................................................................25

B. Non-metallic materials .........................................................25

Sec. 2 Metallic Materials, Machining, Welding and Joints.................................................................... 26

A. Aluminium materials ............................................................26

B. Steel materials.......................................................................27

Sec. 3 Fibre Reinforced Plastics................................... 29A. Material properties................................................................29

B. Manufacturing.......................................................................29

Sec. 4 Thermoplastics.................................................... 32A. Polyethylene and ABS..........................................................32

Sec. 5 Other Materials .................................................. 34A. Buoyancy materials ..............................................................34

B. Fabrics for RIB collars..........................................................34

C. Wood ....................................................................................34

Sec. 6 Tables Of Material Properties........................... 35A. Reinforcement fibres, resin and core products .....................35

B. Sandwich adhesives ..............................................................35

C. Polyethylene and ABS..........................................................36

CH. 4 STRUCTURES .................................................... 39

Sec. 1 Design Principles ................................................ 41A. Documentation......................................................................41

B. Alternative design standards.................................................41

Sec. 2 Design Loads ....................................................... 42A. General.................................................................................42

B. Design loads .........................................................................42

Sec. 3 Aluminium and Steel Structural Design .......... 45A. General..................................................................................45

B. Structural arrangement..........................................................46

C. Steel and aluminium plating .................................................48

D. Frames, girders and stiffeners...............................................49

E. Pillars ....................................................................................50

Sec. 4 FRP Structural Design....................................... 51A. General..................................................................................51

B. Structural arrangement..........................................................52

C. Single skin constructions ......................................................54

D. Sandwich constructions ........................................................55

E. Frames, girder and stiffeners ................................................58

Sec. 5 Thermoplastic Structural Design...................... 61A. General..................................................................................61

B. Rotation moulding of polyethylene boats.............................61

C. Thermoforming of ABS-sheets.............................................61

D. Boat construction ..................................................................62

E. Polyethylene .........................................................................62

F. Acrylnitrilbutadienestyrene (ABS) and equivalent materials................................................................................62


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CH. 5 MACHINERY AND SYSTEMS ........................ 65

Sec. 1 Machinery ........................................................... 67A. Certification .......................................................................... 67

B. Propulsion and auxiliary engines ......................................... 67

Sec. 2 Driven units......................................................... 68A. Shafting ................................................................................ 68

B. Shaft brackets and stern tubes .............................................. 68

C. Gears, propellers and waterjets ............................................ 68

Sec. 3 Steering ............................................................... 69A. Definitions ........................................................................... 69

B. Arrangements ....................................................................... 69

C. Forces on steering system..................................................... 69

D. Rudder stock ......................................................................... 69

E. Rudder .................................................................................. 70

F. Steering system..................................................................... 70

Sec. 4 Piping Systems and Tanks ................................ 71A. General.................................................................................. 71

B. Bilge System ........................................................................ 71

C. Fuel system........................................................................... 71

D. Seawater cooling systems..................................................... 72

E. Freshwater systems and grey water systems ........................ 72

F. Shell penetrations ................................................................ 72

Sec. 5 Electrical Systems .............................................. 73A. Scope .................................................................................... 73

B. DC systems – Voltage ≤ 50 V ..............................................73C. AC systems – Voltage ≤ 240 V ............................................73D. Emergency power supply .....................................................74

Sec. 6 Fire Safety........................................................... 75A. General..................................................................................75B. Structural fire protection.......................................................75C. Portable fire extinguishers ....................................................75D. Fire detection ........................................................................75E. Fixed fire extinguishing systems ..........................................75

Sec. 7 Navigation .......................................................... 77A. General .................................................................................77

Sec. 8 Other systems .................................................... 78A. Cocking and heating appliances ...........................................78B. LPG installations ..................................................................78

CH. 6 OUTBOARD ENGINE INSTALLATIONS..... 79

Sec. 1 Outboard Installations....................................... 81A. General..................................................................................81

CH. 7 CRAFT WITH NOTATION PASSENGER.... 83

Sec. 1 Craft with Notation Passenger....................... 85A. Application ...........................................................................85B. Passenger accommodation....................................................85C. Emergency exits....................................................................85D. Intact and damaged stability .................................................85E. Fire safety ............................................................................85

DET NORSKE VERITASVeritasveien 1, NO-1322 Høvik, Norway Tel.: +47 67 57 99 00 Fax: +47 67 57 99 11

STANDARD FOR CERTIFICATION OF CRAFT

CHAPTER 1

GENERAL REGULATIONS

CONTENTS PAGE

Sec. 1 Introduction ................................................................................................................................ 9Sec. 2 Certification systematics .......................................................................................................... 10Sec. 3 Procedures ................................................................................................................................ 11Sec. 4 Testing/Sea Trials..................................................................................................................... 13Sec. 5 Definitions................................................................................................................................ 14

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Standard for Certification of Craft, April 2008Ch.1 Sec.1 –

SECTION 1 INTRODUCTION

A. ScopeA 100 General101 The purpose of this Standard is to provide a certificationservice for the small craft industry; mainly for Commercialcraft, but also Recreational craft outside scope of EU Direc-tives.102 This Standard is developed by the Society and is basedon previous DNV Rules for Certification and the Nordic BoatStandard.103 The certification aims at providing an appropriate safetylevel for the boat types, their intended application and designlimitations. The technical and safety standards prescribed areconsidered adequate for Commercial craft with overall lengthsin the approximate range 6 to 24 m and with speedup to 45knots. Craft with lengths and /or maximum speed other than in-dicated may be certified upon special consideration.104 The certification services described in this Standard ap-ply to newbuilding of craft. No services for the operationalphase are provided.105 Certification according to this Standard does not ensurecompliance with any mandatory national or international reg-ulations.

B. RequirementsB 100 General101 The regulations with respect to certification systematicand formalities are given in this chapter. The technical require-ments are given in Ch.1 to Ch.6. The specific requirements forthe various types of craft are given in Ch.7 102 The requirements which are in force at the date of thewritten agreement are the basis for the certification. The re-quirements of this Standard are available in electronic format,but printed issues may also be available

C. Recreational Craft

C 100 General101 Recreational Craft within the scope of EU Council Di-rective 94/25/EC as amended (RCD) will be assessed by DNVas Notified Body according to the assessment procedures ofRCD.The assessment will be based on the requirements of the har-monised ISO standards mandated for RCD.102 Certificates for recreational craft within the scope ofRCD will be issued by DNV as Notified Body in accordancewith RCD. No other certificates will be issued.103 Recreational craft outside the scope of RCD shall followthe systematic and procedures specified in Sec. 2 and Sec. 3,and will be assessed based on the technical requirements givenin Ch.1 to Ch.6. Harmonised ISO standard mandated for RCD may also be ap-plied.

C 200 Certification Plate201 A Certification Plate will be issued by DNV for recrea-tional craft with certificate(s) in accordance with:

— EU module G or Ch.1 Sec. 3A One-off craft (Module G) — EU modules B+F or Ch.1 Sec.3 B200 Type Approval

(Module B) and B300 Product verification (Module F) — EU modules B+D or Ch.1 Sec.3.

202 Type Approval (Module B) and B400 Production verifi-cation (Module D) 202The plate will show the following text:"This boat is certified as a Recreational Craft by Det NorskeVeritas according to DNV's Standard for Certification ofCraft". In addition a unique number for identification will beshown. The plate will also give general information aboutDNV.

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Standard for Certification of Craft, April 2008 – Ch.1 Sec.2

SECTION 2 CERTIFICATION SYSTEMATICS

A. GeneralA 100 General101 The relation between the Customer and DNV is regulat-ed in an Agreement signed by both parties. The agreementspecifies the scope of the service, the fee, terms of paymentand legal obligations.102 The certification service is performed on the basic as-sumption that all parties involved (designer, builder/yard,manufacturer, design-owner, sub-contractor, owner, etc.) fulfiltheir individual obligations. The certification service is notperformed in substitution of other parties' role or obligations.Nothing contained in DNV services, certificate, report or doc-ument issued in connection with or pursuant to these require-ments, shall relieve any designer, engineer, builder,manufacturer, yard, seller, owner, operator or other partiesfrom any obligations or consequences of default whatsoever.In particular, compliance with the requirements does not implyacceptance or commissioning of a craft. This is the exclusiveresponsibility of the owner.

B. Certification - ProceduresB 100 General101 The certification Procedures are based on Modules.These procedures (modules) cover the design phase, the man-ufacturing phase or both. The procedures are based on themodules specified for conformity assessment in accordancewith the Directives in the European Union and are described inSec. 3 - Information about what procedures to choose and de-tailed requirements for each module are given in Sec. 3. 102 Application for certification shall be sent to the localDNV office and include:

— name and address of the applicant— name and address of the owner of the design.— name and address of the builder (yard, manufacturer) craft

specification and type designation— chosen procedure(s) — technical documentation.

103 The Applicant has to be authorised by the Owner of thedesign to act on his behalf.104 If the Applicant subcontract design or production, theapplicant remains responsible for the execution of conformityassessment for all technical documentation, sub-supplies andthe finished craft.105 Any Subcontracting will be subject for separate agree-ment, handling and approval.106 The Society decides the extent of examinations, tests

and inspections required to complete the relevant procedure(module) in each case.107 Requirement for Manufacturing shall be surveyed andaccepted according to requirement in Ch.3 Sec.2: Metallic ma-terials and Ch.3 Sec.3: Fibre reinforced plastics-FRP.

C. Technical documentationC 100 General101 The Applicant shall submit Technical Documentationfor approval irrespective of certification procedure.102 Technical Documentation shall enable understanding ofthe design and construction of the craft, and shall confirm com-pliance with the requirements given in this Standard.103 Requirements for documentation is found in the begin-ning of each Section:

— Stability Ch.2 Sec.2: A200— Materials Ch.3 Sec.1: A and B, Ch.3 Sec.3: A and Ch.4

Sec.4: A700, A800,— Safety Ch.2 Sec.3: A — Structure Ch.4 Sec.1: A (for speed exceeding 45 knots, see

B)— Systems Ch.5: (Principle Schemes shall show compliance

with requirements in text).

104 Documentation of Quality Assurance System (moduleD) shall be according to Section 3 B400

D. CertificatesD 100 General101 The type of certificates to be issued by DNV will be:

— Product Certificate (A203, B305)— Type Approval Certificate (B205)— Quality System Production Certificate (B408)

102 The certificates shall contain the following informationas applicable:

— the name and address of the Builder (yard, manufacturer)— the identification of the product- craft type designation and

reference to Owner of the design— reference to the Standard and regulations applied— specification of exemptions or equivalent standards— any restrictions/limitations in the use of the craft— validity— date of issue and signatures.

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SECTION 3 PROCEDURES

A. One-off craft (Module G)A 100 General101 The procedure (module) is applicable for One-off certi-fication, i.e. a design on which only one craft is built.

A 200 Procedure201 DNV will verify that the Technical Documentation com-plies with the requirements. 202 DNV will carry out surveys during production, examinethe complete craft and carry out the appropriate tests as set outin the relevant requirements to ensure its conformity.203 Upon successful completion of the certification proce-dure, DNV will issue a Product Certificate.

B. Series of craft (Module B and F or D)B 100 General101 The procedures (modules) described in B200, B300 andB400 are applicable to one design on which a series of craft ismanufactured. B200 covers the design phase and shall alwaysbe followed by a procedure covering the production phase(B300 or B400)

B 200 Type Approval (Module B)201 The procedure (module) shall normally be used for ap-proval of a design produced in series and must be followed bya procedure (module) covering the production phase.202 The procedure shall be according to: DNV Standard forCertification - No.1.2 Type Approval.

Guidance note:Overall principles for Type Approval (TA):

— Application for TA— Quotation — Approval of the design— Initial survey— Type testing— Issuance of TA certificate

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203 DNV verifies that the Technical Documentation com-plies with the requirements.204 DNV verifies, by performing examinations and tests thatone prototype complies with the applicable requirements andis built in accordance with the Technical Documentation.205 Upon successful completion with the certification pro-cedure, DNV will issue a Type Approval Certificate with va-lidity of 4 years.

B 300 Product verification (Module F)301 The procedure (module) covers the production phaseand follows Procedure for Type Approval (Module B). 302 The builder shall take necessary actions to ensure thatthe manufacturing process ensures conformity of the productswith the types as described in the approved Technical Docu-mentation.303 DNV will carry out the appropriate examinations andtests in order to check the conformity of the product with theapproved technical documentation, either by examination and

testing of every product (303), or alternatively by examinationand testing of products on a statistical basis (304).304 Normally all products will be individually examined andappropriate tests carried out in order to verify their conformitywith the type as described in the Type Approval Certificate andthe approved Technical Documentation.305 If statistical verification is agreed, the method shall beaccording to ISO 2859-1:

— Each relevant section shall be considered as an inspectionitem.

— Sample size shall be based on Table 1, General InspectionLevel "I"

— Sampling plan shall be according to Table 2-A— Acceptance Quality Limit (AQL) shall be 1,0

If a lot is found not acceptable, all items shall be re-examineduntil DNV is satisfied that all nonconforming items have beenrectified/replaced. DNV will determine whether the re-exami-nation shall include all inspection items, or only the particulartypes of nonconformities which caused initial non-acceptance.306 Upon successful completion of the certification proce-dure, DNV will issue a Product Certificate.

B 400 Production verification (Module D)401 The procedure (module) covers the production phaseand follows procedure for Type Approval (Module B). 402 The builder shall operate an approved Quality Assur-ance System (QA-system) for manufacturing, final product in-spection and testing. The QA-system shall be subject tomonitoring as specified below.403 The procedure may cover several designs with validType Approval Certificate.404 The builder shall submit the documentation concerningthe QA-system. The QA-system shall ensure compliance of theproducts with the type(s) as described in the Type ApprovalCertificate(s) and the approved Technical Documentation.405 All the elements, requirements and provisions adoptedby the manufacturer shall be documented in a systematic andorderly manner in the form of written policies, procedures andinstructions.406 The QA-system documentation must permit a consistentinterpretation of the quality programmes, plan, manuals andrecords.407 The QA-system shall contain in particular an adequatedescription of:

— the quality objectives and the organizational structure, re-sponsibilities and powers of the management with regardto product quality

— the manufacturing, quality control and quality assurancetechniques, processes and systematic actions that will beused

— the examinations and tests that will be carried out before,during and after manufacture, and the frequency withwhich they will be carried out

— the quality records, such as inspection reports and test da-ta, calibration data, qualification reports of personnel con-cerned, etc.

— the means to monitor the achievements of required productquality and the effective operation of the quality system.

408 Upon successful approval of the QA-system DNV willissues a Quality System Production Certificate valid for 4

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years. 409 DNV will carry out audits to make sure that the buildermaintains and applies the quality system. The audit will in-

clude spot checks on craft under building and review of qualityrecords of built craft. 410 Additionally DNV may pay unexpected visits.

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SECTION 4 TESTING/SEA TRIALS

A. GeneralA 100 General101 All equipment shall be function tested after installationto demonstrate compliance with the requirements in this stand-

ard. The testing shall include sea trial(s) with all equipment in-stalled. All testing shall be carried out according to a planapproved by the surveyor. The surveyor may require witness-ing of all or part of the testing and/or sea trials.

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SECTION 5 DEFINITIONS

Symbol Unit Description

L m Length of hull but excluding rubrails, outside rudders, outdrives, outboard motors, diving platforms, bowsprits, fittings.

LWL m Length of hull along waterline measured at the foremost intersection of the stem with the flotation plane and the aftermost intersection of the hull and the flotation plane.

B m Maximum beam of hull measured on the outside of the hull shell.BWL m Beam of hull in the waterline. For catamarans: sum of waterline beam for both hulls.T m Maximum draught of hull in fully loaded condition.

D m Depth, measured as the vertical distance between the sheerline at the half-length of the waterline and the lowest point of the keel.

Δ kg Displacement in fully loaded condition.V knots Maximum speed. β ° Deadrise angle is the angle of the bottom from the horizontal measured athwartship at a specific position.LCG m Longitudinal position of the centre of gravity from a chosen datum.VCG m Vertical position of the centre of gravity from a chosen datum.RM Nm Righting moment.GM m Transverse metacentric height.GZ m Righting lever = righting moment (Nm)/(mass (kg) x 9,806).

Decked craft Craft with deck that can be closed weather tight from stem to stern uninterrupted by other than a strong superstructure or a cockpit so designed that shipping sea will not fill spaces below deck.

Open craft Craft that is not a decked craft.Flooded craft A flooded craft is a craft in a condition in which it can not be filled with more water.

Superstructure Decked structure on the freeboard deck, extending from side to side of the ship or with the side plating not inboard of the shell plating more than 4% of the breadth (B).

Deckhouse Decked structure above the strength deck with the side plating being inboard of the shell plating more than 4% of the breadth (B).

Long deckhouse Deckhouse having more than 0,2 L of its length within 0,4 L amidships.Short deckhouse Deckhouse not defined as a long deckhouse.Mean freeboard F mm F = (ff + fm +fa)/3 ff mm Freeboard measured at extreme forward end.

fa mm Smallest freeboard measured at extreme aft end or, for craft with engine wells to the point where water first may enter the craft.

fm mm Freeboard measured at LH/2.

Headroom m Vertical distance between top of compartment floor and underside of the deck beam or deck head (whichever is the lower).

Readily accessible Capable of being reached for operation, inspection or maintenance without the use of tools or the remov-al of any craft structure or any item of portable equipment.

Accessible Capable of being reached for operation, inspection or maintenance without the removal any permanent craft structure.

M kNm Maximum longitudinal bending moment.Z mm3 Section modulus of hull girder.Recreational craft Any craft of any type intended for sport and/or leisure of hull length up to 24 m, regardless of means of

propulsion.Manufacturer The entity putting the product on the market.



CHAPTER 2

ARRANGEMENT, STABILITY AND SAFETY

CONTENTS PAGE

Sec. 1 Arrangement............................................................................................................................. 17Sec. 2 Stability, Water- and Weathertight Integrity............................................................................ 19Sec. 3 Safety of Personnel .................................................................................................................. 22

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SECTION 1 ARRANGEMENT

A. GeneralA 100 Bulkheads101 Craft with length 6 m < L < 15 m shall normally be ar-ranged with at least 2 watertight bulkheads. 102 Craft with length L exceeding 15 metres shall be ar-ranged with at least 3 watertight bulkheads, of which one shallbe a collision bulkhead with minimum distance 0.05L fromforward perpendicular.103 Watertight bulkheads shall be carried up to freeboard(bulkhead) deck, or may end at first deck above waterlinebased on special consideration of watertight division and in-tegrity of the hull.104 Engine compartment and cargo hold are to be separatedfrom each other and from rest of the hull by watertight bulk-heads. Minor steps or recesses in the bulkhead may be accept-ed. For craft with length, L, less than 15 m, the enginecompartment may be accepted as a watertight box up to a levelabove waterline based on special consideration.105 Doors and hatches in watertight bulkhead may be ac-cepted. 106 Small openings for penetrating pipes and electrical ca-bles shall normally be sealed and arranged in top of bulkheads.

B. AccommodationB 100 General101 Accommodation areas shall be without sharp cornersand protruding parts and shall not be made of material whichmay brake into dangerous fragments. It shall not contain un-shielded high temperature areas, high pressure or rotatingitems, and shall not contain operating controls located in a wayto be impeded by persons during normal and emergency con-ditions.

B 200 Seats201 A seat shall be arranged for every person onboard.202 A seat shall have the following minimum size:

— beam 500 mm— depth 750 mm, free space for legs measured from persons

back — height 900 mm, from seat to free height for head.

Sharp edges, arm rest etc. which may cause injury are not ac-cepted.203 The strength of a seat shall be in accordance with the rel-evant horizontal longitudinal acceleration of the craft. In gen-eral a minimum static load of 1125 N may be used as basic forthe scantling. The point of application of the horizontal longi-tudinal load shall be at the top of the backrest. Seats shall bedesigned for a vertical load equal to 2 250 N. The point of ap-plication of the vertical load shall be at the centre of the seat.204 For craft with speed exceeding 15 knots, the seats onopen decks shall be minimum 100 mm lower than top of bul-wark/railing. Equivalent arrangements for protecting personsfrom falling overboard when seated can be accepted.205 For craft with speed exceeding 45 knots the seats shallbe equipped with seat belt.

B 300 Ventilation 301 Accommodation spaces shall have separate inlet and ex-haust of air, with documented capacity of ventilation for com-fort of persons with closed windows and doors.302 Heating, cooking and similar installations shall haveseparate ventilation.303 Inlets and outlets of ventilation shall be well separatedfrom engine exhausts.304 All compartments, holds and void spaces shall normallyhave natural ventilation.305 Any space intended for flammable liquids etc. shall haveseparate ventilation.

B 400 Sanitary401 All craft shall normally be arranged with basic sanitaryfacilities (toilet and wash basin). This requirement may bewaived for craft for limited operation in harbour etc.

B 500 Exit, Passages etc. 501 All accommodation, and machinery-spaces that are pos-sible to enter, shall normally be arranged with two exits, forwhich one may be an emergency exit. The exits shall be locat-ed as far as possible from each other, and be suitable to use inemergency situation.502 Width of passages shall be minimum 700 mm in general,but may be reduced to 600 mm for spaces not normally used.503 Accommodation for maximum 4 persons may be accept-ed with only one exit if this cannot be blocked in case of fire orother emergency situation and if it leads directly to open deck.

B 600 Emergency exit601 The emergency exit can be an approved hatch, door orwindow complying with the following:

— minimum light opening 500 x 500 mm, or diameter 450mm

— easy access with fixed step, ladder and handholds as nec-essary

— clearly marked and with appropriate instructions for use.— readily opened from both sides without tools in daylight

and dark— direct access to open deck, or via short passages without

any lockable door.

B 700 Emergency light701 Emergency light is to be arranged for accommodationand exits.

C. WheelhouseC 100 General101 The design and layout of the wheelhouse shall allow thecrew to perform their duties without difficulty, fatigue or lossof concentration. The headroom in the wheelhouse shall beminimum 1980 mm.102 The wheelhouse shall normally not be used for purposesother than navigation, communication and functions essentialto the operation of the craft. Fixed seats shall be arranged forcrew.

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C 200 Field of vision201 The wheelhouse shall be so arranged and positioned toprovide view all round the horizon from the steering and navi-gation workstations. Where this is not possible, the all roundview of the horizon may be obtained by using two combinedworkstations, or by another approved mean.202 The view of the sea surface from the operating stationwhen seated, shall not be obscured by more than two craftlength forward of the bow to 90° on either side irrespective ofthe craft’s draught and trim.203 Blind sectors shall be as few and as small as possible,and not adversely affect the keeping of a safe look-out from theoperating station. The total arc of blind sectors from rightahead to 22.5° abaft the beam on either side shall not exceed20°. Each individual blind sector shall not exceed 5°. The clearsector between two blind sectors shall not be smaller than 10°.204 Arrangement shall be provide so that forward view is notadversely affected by solar glare. Neither polarised nor tintedwindow glass shall be fitted in the front and side of the wheel-house. Removable sunscreens/curtains may be provided. Win-dows should preferably be angled top outboard approx 15°from vertical to reduce unwanted reflection.205 Tinted glass or material which may easily be scratchedis not accepted in front and side of wheelhouse windows. Spe-cial arrangement where free sight is arranged above the tinted

glass may be accepted. Windows shall not break into danger-ous fragments if fractured.

C 300 Instruments and equipment301 The equipment and means for navigation, manoeuvring,control, communication and other essential instruments shallbe located sufficiently close together to enable personnel to re-ceive information and to use the equipment while seated. Ifnecessary some functions may be duplicated. A table for chartwork shall normally be arranged.302 Instrument, their panels and controls shall be perma-nently mounted in consol(s) convenient for operation andmaintenance. The surface of console tops and instruments shallprevent light reflections.303 All instruments shall be logically grouped according totheir functions, plainly visible and easily readable. Means forscreening and dimming of internal and external lights in orderto minimise glare and reflections, shall be arranged.304 All craft shall be provided with a magnetic compasswhich is capable of operating without electrical supply, andwhich may be used for steering. This compass shall be mount-ed in a suitable binnacle containing the required corrective de-vices and shall be suitable for the speed and motion of theactual craft.

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SECTION 2 STABILITY, WATER- AND WEATHERTIGHT INTEGRITY

A. General

A 100 Assumptions 101 No damage stability calculation is required. 102 For craft required to be arranged with buoyancy ele-ments, the capability in swamped condition shall be document-ed and verified by full scale test. Enclosed superstructure,deckhouses and trunks may be included as buoyancy elementsprovided they have approved strength and closing appliances.103 Marks for maximum draught are to be arranged at bowand stern. 104 Permanent heel or trim which may generate danger foraccumulation of water on deck is not accepted.

A 200 Documentation 201 The following documentation shall be submitted for ap-proval:

— stability manual— inclining test— closing appliances.

The following documentation is assumed for information:

— general arrangement— body/lines plan— freeboard/weathertight integrity plan.

202 The stability manual shall cover all load conditions rep-resentative for the intended service of the craft, includingdrafts, trim and freeboard. The manual (or a separate appendix/issue) shall also include relevant hydrostatic data, calculationof centres of gravities etc. Stability curves shall be made on afree to trim basis. (Cross curves are normally to be prepared ona designed trim basis). 203 The inclining test is generally to be carried out and doc-umented according to ordinary practice for ship. For craft withlength L less than 6 m, and crafts arranged with buoyancy, theordinary inclining test may be replaced by a full scale stabilitytest.

B. Freeboard

B 100 Decked crafts101 The freeboard shall nowhere be less than 200 mm. 102 The height of the forecastle or bulwark at stem shall nor-mally nowhere be less than 0.12 L above deepest waterline.The height may be reduced to the level of freeboard deck at0.25 L from the stem and aftwards.

B 200 Open craft and all craft with buoyancy elements 201 The mean freeboard, F, shall not be less than the largerof:

orFmin = 500 mm

Craft not complying with requirement above, shall be arrangedwith buoyancy elements.202 Craft with length L < 6 m shall be arranged with buoy-ancy elements.203 For craft arranged with buoyancy elements, the meanfreeboard, F, shall not be less than:

F = 200 B mm, or Fmin = 200 mm.

204 Craft shall have a freeboard aft of not less than:Faft = 0.8 F. 205 Craft that neither complies with the requirements tofreeboard nor has buoyancy elements arranged, shall be ar-ranged as Decked craft.

C. Stability – Decked craft

C 100 Decked Craft101 The stability manual shall document the righting armGZ for the following conditions:

a) Lightship with minimum equipment and cargo. Combinedloads are not to exceed 10% of maximum load capacity.

b) Loaded with maximum equipment and cargo in holds andon deck. Combined loads are not to be less than 90% ofmaximum load capacity in the mode of departure and ar-rival.

c) Deck load with maximum equipment and cargo on deckand empty holds in the mode of departure and arrival.

d) Other relevant conditions shall be documented.

102 The righting arm at 30° heel is to be minimum 0.20 me-tres. The maximum value of the GZ-curve shall occur at an an-gle not smaller than 25°. The GZ curve shall normally bepositive up to 50° of heel. 103 When calculating the heeling moment due to operationof lifting gear, winch, towing hook etc., a dynamic factor of 1.4is normally to be used to include effects from wind, waves etc.The heel of the craft shall not exceed 12° for maximum mo-ment in the most unfavourable condition.

D. Stability – Open craft

D 100 Open craft101 An inclining test may be carried out to determine themetacentric height GM in lightship condition. GM shall nor-mally not be smaller than 0.50 m.102 The inclining test may be omitted if it for the load con-dition can be demonstrated that the period of roll in seconds(from one side and back to the same side) is less or equal to thecraft beam in meters.103 The requirement to metacentric height, or period of roll,may be disregarded if it is documented that the GZ curves sat-isfy the requirements for Decked craft up to 30°.

F 4.5Δ1000 LB-------------------- (mm)=

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E. Stability - Open craft with buoyancy

E 100 Stability in intact condition101 In lightweight condition the craft is not to be flooded, orthe angle of heel is not to exceed 10°, for a heeling weight:

P = 20 x n kg (n = number of persons), orPmin = 40 kg.

The heeling weight is to be placed at the gunwale at the maxi-mum beam of the craft, and not less than Bmax/2 from the cen-treline.102 In maximum load condition the craft shall not capsize orbe flooded if all persons moves to the same side, the angle ofheel is not to exceed 10°, caused by a heeling weight: P = 75 x n kg (n = total number of persons). The weight is to be located on the floor as near to the gunwaleas possible, but minimum Bmax/4 from centreline and with lon-gitudinal position corresponding to the arrangement of the ac-commodation. Weights representing equipment shall belocated at their respective positions.

E 200 Buoyancy in flooded condition201 In maximum load condition (including any outboard en-gine) the flooded craft is to float approximately horizontal andnot sink when loaded with additional weight:

P = 25 x n kg (n = total number of persons), but not less than the larger of

P = 50 + 50 (L – 2.5) kg, or Pmin = 75 kg.

Weights shall be located at their respective positions on board.

E 300 Stability in flooded condition301 In maximum load condition (including any outboard en-gine) the flooded craft shall have a positive stability up to 50°of heel when loaded with a weight PK = 10 + 5 x n kg (n = totalnumber of persons), or PKmin = 25 kg, located anywhere alongthe gunwale.

F. Freeing ports and drainage

F 100 Freeing ports on decked craft101 Freeing ports shall be spaced along the deck, with loweredge normally flush with deck level. 102 On craft with bulwark, forecastle, deckhouse or openstructures forming wells, the total freeing port area on eachside of the deck is to be minimum A = 0.02 V m2. The volumeV is calculated based on total deck area and height to top ofbulwark, with deduction of volume of hatches, deck-house etc. 103 Flaps at freeing ports may be approved if opening area isnot reduced, jamming is prevented and hinges are made ofnon-corrosive material. Locking of flaps is not permitted.104 Freeing port openings shall be fitted with bars not morethan 330 mm apart, and with maximum 230 mm opening be-low the lowest bar.

F 200 Drainage of open craft201 Drainage of deck shall be arranged from each side of thecraft to the bilge, from which pumping shall be arranged. Thedrainage may also be directly overboard with a non-return ar-rangement, or a closeable arrangement.202 The area of drainage shall be minimum A = 0.01 V m2,where V is the volume as defined as for decked craft.

G. Weathertight integrityG 100 General101 Small openings for wire chain, scuppers etc., will beconsidered as closed if submerged at angle of heel larger than30°.102 Openings to spaces below freeboard deck, or to otherspaces included as buoyancy in stability calculations, shall befitted with weathertight closing appliances. 103 Closing appliances shall be built with same strength asthe surrounding structure and be arranged to provide safetyagainst sea impact.104 Closing appliances shall as a minimum include gasketand two closing devices in addition to hinges.

G 200 Hatches201 Weathertight hatches shall have:

— permanent gasket— cleats fitted with maximum 600 mm spacing measured

along the periphery of the hatch.

202 Hatches which may be opened at sea shall be hinged orattached by chain and shall be capable of being secured in openposition.203 Hatch coamings shall normally have a height of at least380 mm. The height of coaming may be reduced, or be flushwith deck if the hatch is not operated when at sea and cleats arefitted with a spacing normally not exceeding 300 mm meas-ured along the periphery, or the hatch is permanently bolted todeck.

G 300 Doors301 Doors shall be possible to operate from either side of thebulkhead.302 The sill height of door openings to spaces below free-board deck shall be at least 380 mm. For doors located at least380 mm above freeboard deck, a reduced height of sill may beaccepted, but normally not less than minimum 150 mm.303 Arrangement for removable washboard replacing a sillmay be accepted based on special consideration.

G 400 Port and ramps401 Port and ramps in freeboard above weathertight deckmay be accepted. Watertightness shall be arranged with gasketand hinges/clamps with spacing not exceeding 300 mm.402 The arrangement for safety of operation, stop arrange-ment and any indicators etc. shall be submitted for approval.403 The lower edge of openings shall not be less than 200mm above deepest waterline.

G 500 Ventilation501 Ventilation openings shall be arranged to avoid floodingof the craft and normally have minimum height 600 mm abovefreeboard deck.502 Ventilation openings shall normally not be immersed atheel angle smaller than 50°.

G 600 Air pipes601 Air pipes are defined as openings for ventilation normal-ly not exceeding an area equivalent to a diameter of 50 mm.602 Air pipes shall be arranged with non-return valve orgoose necks to prevent water ingress.603 The height of air pipes shall normally not be smallerthan 600 mm above the freeboard deck.604 Air pipes shall be protected from damage from work ondeck.

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G 700 Windows701 Windows in accommodation spaces may be fabricatedfrom thermally or chemically toughened glass or polycar-bonate. Windows shall not fracture in fragments that can easilycause human injury.702 Windows shall be fitted in rigid frames and secured frombeing pressed in. A rubber profile is acceptable if the windowcan not be pressed in and the glass thickness is increased by20%.703 The minimum thickness of windows shall be calculated

according to the following formula:

P = design pressure at the location of the windowβ = according to the figure belowa = the larger dimension of the window openingb = the smaller dimension of the window openingK = 190 for glass

= 160 for polycarbonate.

Figure 1

704 For windows placed above positions exposed to sea-loadthe thickness may be reduced by 25%.705 Horizontal windows in positions exposed to impact fromoperation are subject to special consideration.

H. Buoyancy elementsH 100 General101 Requirements for buoyancy elements are given in Ch.3. 102 Buoyancy elements may consist of foam, prefabricatedor formed in position (in-situ), or tanks and double hull filledwith air or buoyancy elements. Buoyancy elements must befixed or permanently fitted and protected against mechanicaldamage and degradation from the environment.103 Drainage shall be arranged for enclosed spaces used for

buoyancy element. Such spaces shall normally not be used forstorage or other facilities.

I. BallastI 100 General101 Ballast shall be arranged so as to prevent shifting of po-sition. The arrangement should have access for inspection.102 The ballast material shall be documented to have no cor-rosive or destructive effect on the hull structure materials. 103 Use of water as ballast may be accepted based on docu-mentation of the arrangement, tanks, filling and operation.104 Ballast on cement-basis shall be specially documentedwith respect to arrangement and chemical reaction to hull ma-terial, drainage and protection.

t bK---- βP=

a/b

0,3

0,4

0,5

0,6

0,7

0,8

1,0 2,0 3,0 4,0 5,0

FAC

TOR

β

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SECTION 3 SAFETY OF PERSONNEL

A. Safety Plan A 100 General101 A safety plan for the craft, shall be submitted for approv-al. The plan shall be delivered with the craft. The requirementmay be waived for craft with length L not exceeding 8 m, orfor craft of simple design and arrangement.102 The safety plan shall describe the arrangements for thefollowing items:

— life saving equipment— fire alarm and fire fighting— emergency exits — emergency systems (alarms, fans, valves etc.).

In addition the following may be included for information:

— emergency instruction— first aids.

B. Railings, Ladders, Handholds, Decks B 100 Rails and handholds 101 All areas above and below deck intended for human oc-cupation shall be equipped with either railings, bulwark, hand-holds of substantial design or other means of safe grip.102 Decks shall normally be surrounded by railing or bul-wark with minimum 750 mm height. Part of the railing may bedismountable.103 The distance between vertical stanchions of railing shallnormally not be more than 1200 mm. The vertical distance be-tween bars in rails shall normally not exceed 230 mm fromdeck level and 330 mm elsewhere.

B 200 Deck non-slip surface201 Non-skid surface shall be arranged on all decks andfloors intended for human occupancy or work.202 Decks shall have a toe-rail of minimum 25 mm height at

the outboard edge or gunwale.

B 300 Outboard rescue ladder 301 For craft with length L exceeding 6 m, or craft with free-board F exceeding 500 mm, an outboard rescue ladder or stepsshall be arranged. The arrangement shall be suitable for a per-son in the water to enter the craft. The lower step, or any suit-able safe part of hull structure to step on, shall be arrangedminimum 500 mm below waterline in light condition of thecraft. 302 A foldable ladder, or other equivalent system, may beaccepted when a safe release system is arranged for accessfrom position in the sea.

B 400 Outboard hand grips 401 For craft required to be fitted with buoyancy units, ar-rangement shall be fitted to enable persons in the water to holdon to the craft in capsized condition.

C. Operation of deck gear

C 100 General101 Winches, cranes and other deck-gear shall be arrangedto facility safe working with respect to instruction, operation,view and shielding. Winches with open lines, lifting platformsand all types of movable deck gear, shall be shielded or ar-ranged with automatic emergency stop activated by a person orother inadequate object caught by the lines or gear in opera-tion. Winch barrel, and similar gears shall have protectionagainst line end etc. hitting the person operating the winch orgear.102 Instruction for safe operation of lifting gears, togetherwith type notation and name of manufacturer, shall be given ona signboard on the gear at the place of operation.103 Testing of safe work load for winches, cranes and otherlifting gears shall be documented, and arrangement to avoidoverload shall be fitted.



CHAPTER 3

MATERIALS AND MANUFACTURING

CONTENTS PAGE

Sec. 1 General Requirements .............................................................................................................. 25Sec. 2 Metallic Materials, Machining, Welding and Joints ................................................................ 26Sec. 3 Fibre Reinforced Plastics ......................................................................................................... 29Sec. 4 Thermoplastics ......................................................................................................................... 32Sec. 5 Other Materials......................................................................................................................... 34Sec. 6 Tables Of Material Properties .................................................................................................. 35

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SECTION 1 GENERAL REQUIREMENTS

A. Metallic materialsA 100 Aluminium alloys101 Structural aluminium material shall be resistant to corro-sion in marine environments.102 Structural aluminium material shall be delivered with aworks certificate.103 Acceptable alloy grades are given in the following table.

104 The use of 6000-series aluminium alloys in direct con-tact with sea water may be restricted depending on applicationand corrosion protection system.105 This chapter is not applicable to aluminium alloys forforgings and castings. For these products suitable alloys ac-cording to recognized standards may be used.

A 200 Steel201 Structural steel materials shall be weldable.202 Structural steel materials shall be delivered with a workscertificate.

203 Structural steel materials shall have a yield point of notless than 235 MPa.

B. Non-metallic materialsB 100 Application101 This section applies to raw materials for FRP structuresand to thermoplastics. Other materials can be considered basedon a case by case evaluation102 Raw materials shall be delivered under a certificationscheme recognized by the society or certified by an institutionrecognized by the society. The following materials shall becertified:

— fibre reinforcements— resin products— sandwich core materials— sandwich adhesives and cement— thermoplastic granulate/powder and sheets.

B 200 Marking of product201 Each lot shall be marked with the manufacturers name,type designation, approval certificate reference, batch numberand date of manufacture202 Products lacking the marking specified in 201 shall besubject to a product control testing verified by a recognized in-stitution

5000 Series 6000 Series5052 6060

5154A 60615754 60635454 6005A5086 608250835383

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SECTION 2 METALLIC MATERIALS, MACHINING, WELDING AND JOINTS

A. Aluminium materialsA 100 General101 Aluminium shall be stored in a way such that corrosionis avoided.

A 200 Machining and forming201 Methods for machining and forming shall be in accord-ance with the material manufacturer's recommendations.

A 300 Joints - general301 Joining of aluminium with other materials shall not leadto galvanic corrosion. Joints of aluminium to stainless steelmay be accepted without galvanic insulation depending on rel-ative surface area of the aluminium and steel components.302 In joints, aluminium to another metal, the materials shallbe galvancially insulated.

A 400 Joints by welding401 All welding shall take place under dry conditions and ata minimum temperature of 5°C. The welding area shall be pro-tected against drafts.402 Welding of construction parts shall be done by a welderor supervised by a welder with approved certificate for the ac-

tual or similar alloy and method of welding.403 Welding procedures shall be approved on site.404 MIG- or TIG- welding shall be used. MIG-welding isnot recommended for thicknesses smaller than 2.0 mm andTIG-welding for thicknesses smaller than 0.7 mm. 405 Spot-welding shall only be used after special considera-tion.406 Weld joints shall be prepared and bevelled in accord-ance with a recognized standard. The edges of the surfaces tobe joined shall be free from burrs.407 The surfaces to be joined shall be cleaned on the top androot sides. The oxide layer shall be removed by brushing,scraping or picking to a minimum distance of 10 mm from thejoint. The surfaces shall be dry when welding starts.408 Welding consumables shall be kept clean and dry andotherwise be stored and handled in accordance with the mak-er's recommendations.

A 500 Joints by riveting501 The rivet dimension, spacing and distance to the edgeshall be in accordance with Table A1. In rivet joints with smallstresses in the plates, other dimensions and spacing may be tol-erated.

Figure 1 Examples of riveted joints

502 Water tight joints shall be at least two-rowed. The rivetspacing in these joints shall not exceed 4 times the rivet diam-eter

503 The difference in diameter between rivet and hole shallnot be larger than shown in the figure below. The holes shallbe burred.

e

e

Single Plate

Double Plate

t

e1

2e

t

ty

yt

it

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Figure 2 Difference in diameter (mm) between hole and rivet versus rivetdiameter (mm)

504 Riveting shall be carried out in such a way that the sur-faces make good contact.Example of tacking and riveting sequence is shown in the fig-ure below.

Figure 3 Tacking and riveting sequence

505 Blind rivets shall not be used in shell plating or stressedjoints.

A 600 Joints by adhesive bonding601 For adhesive bonds, static and dynamic strength includ-ing peel strength and impact resistance shall be documented.602 The adhesive shall have such properties that the strengthof the joint does not substantially deteriorate by temperaturevariations, water or other substances to which the joint will beexposed.603 The bonding process shall be in accordance with the ad-hesive manufacturer's recommendations. Special considera-tion shall be given the pre-treatment of the surfaces to bebonded.

A 700 Other joints701 Joints with through-bolts shall be designed as rivetedjoints. Self tapping screws are only allowed above waterline injoints carrying insignificant loads.

702 Bolts and nuts in joints below waterline shall be of alu-minium or stainless steel. Galvanised steel may be allowedelsewhere.703 Below waterline connections to stainless steel shall begalvanically insulated from the shell plating.

B. Steel materialsB 100 General101 Steel material shall be stored in a way that corrosion isavoided

B 200 Welding201 Welding of construction parts shall be done by or super-vised by a welder with approved certificate for the actual orsimilar material and method of welding.202 Welding procedures shall be approved on site.203 Welding electrodes shall be stored in a dry and cleanplace.204 Gas-shielded welding shall be performed indoors.205 Horizontal welding shall be used as far as possible 206 The seams shall be cleaned and free from damagingpaint, rust and dirt before welding.207 Shop primer used shall be of a type that is possible toweld without leaving any damaging effect to the strength of thewelding.208 Welds shall have a minimum throat thickness accordingto the following table:

Figure 4 Throat thickness, a

209 The following items shall be welded with double sidecontinuous fillet welding:

210 For intermittent welding, the weld length and spacing

Table A1 Rivet joints

Rivet diameter, d

Single plate joint d = 2·t + 1d = 3·t

t < 1 mmfor t ≥ 1 mm

Double plate joints

d = 1.2·t + 1d = 1.5·t

for t < 3.3 mmfor t ≥ 3.3 mm

Spacing for load-carry-ing rivets

One row of rivets in the load direc-tion

2.5·d ≤ e ≤ 6·d

Two rows of riv-ets in the load di-rection

4·d ≤ e ≤ 7·d3·d ≤ e1 ≤ 5·d

Edge distance

Perpendicular and parallel to the direction of the load

The larger of:e2 ≥ 2·de2 ≥ 4·t

0

0.4

0.2

2 4 6 8 10 12

(mm)

Rivet diameter

(mm)

3 1 5 426

TACKING

Plate thickness (mm)

Throat thickness, a (mm)

< 4 2.04 – 6.5 2.56.4 – 8 3.0

> 8 0.45 x thickness of thinnest plate

Continuous welding

Brackets for beams and other means of supportTransverse frames below waterline and floors Foundations for engine(s), propulsion and equipmentKeel and stem

t

a

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shall be according to the following table:

Figure 5 Intermittent welding

Thickness of plate: t (mm)

Weld length: l (mm)

Spacing: e (mm)

3 – 4.5 50 1005 – 6.5 65 1307 – 8.5 75 150

9 – 10.5 100 200

e

l

e

l

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SECTION 3 FIBRE REINFORCED PLASTICS

A. Material propertiesA 100 General101 This section applies to fibre reinforced thermosets.102 The manufacturer shall keep necessary information re-garding the raw material.

A 200 Properties of reinforcement fibres, resins, core materials and core adhesives201 The materials shall comply with the requirements givenin one of the following standards:

— DNV standards for certification— ISO 12215-1— other recognized standards.

A 300 Core adhesives301 If a standard for core adhesives is not available, core ad-hesives shall comply with the requirements given in the Sec.6.302 Requirements for un-cured material are given in Sec.6B100.303 Requirements for cured material are given in Sec.6B200.304 The approval of sandwich adhesives is separated intotwo different quality grades:

Grade 1: Required quality of sandwich adhesives for hullconstructions

Grade 2: Required quality of sandwich adhesives for lesscritical applications.

The approval shall be related to a set of physical propertieswhich shall be specified in the Type Approval Certificate. Theminimum properties shall be specified by the manufacturerand verified by the approval testing.

B. ManufacturingB 100 Introduction101 In this section requirements related to the manufactur-ing, quality assurance and quality control of FRP structures aregiven. It is to be recognised by the yard that there are limitedor no means for non-destructive examination of FRP structuresavailable. The yard shall therefore recognise the importance ofexercising a rigorous control of all steps of the fabrication toascertain that the finished product complies with its specifica-tion(s).102 The use of fabricating procedures differing from thosespecified in this section will be subject to special considera-tion.

B 200 Storage of Raw Materials201 Storage premises shall be so equipped and arranged thatthe material supplier’s directions for storage and handling ofthe raw materials can be followed.202 Storage premises for reinforcement materials shall bekept dry and clean so that the raw material is not contaminated.The materials shall be stored in unbroken original packagingbefore being used. Materials on which the original packaginghas been broken shall be adequately protected against contam-ination when stored again after use.

203 Reinforcement materials shall normally be stored at thesame temperature and humidity as the workshop in which theyare going to be used. If the storage temperature is not the samethe material shall be acclimatised at the workshop temperatureand humidity prior to being deployed. The time of acclimatisa-tion shall be adequate for the amount of reinforcement: for un-broken packages the acclimatisation shall have duration of atleast two days.204 Resins, gelcoat, hardeners, additives etc. shall be storedaccording to the manufacturers recommendations as regardstemperature, shelf life etc. Raw materials which are stored attemperatures lower than + 18°C shall be acclimatised to thetemperature of the workshop prior to being used. Tanks for res-ins etc. are to be handled during storage according to the man-ufacturer’s recommendations and equipped and arrangedaccordingly.205 Core materials shall be stored dry and protected againstcontamination and mechanical damage. Core materials shallnormally be stored at the same temperature as the workshop inwhich they are going to be used. If the storage temperature isnot the same the material shall be acclimatised for at the work-shop temperature and humidity prior to being deployed.206 Core materials shall be stored in such a way that out-gas-sing of the material is ensured prior to being used. Outgassingshall be carried out according to the manufacturer’s recom-mendations. When new free surfaces are created in the materi-al, e.g. by sanding, cutting or machining, proper outgassingshall be ensured again.207 Pre-pregs shall be stored according to the manufacturer'srecommendation. For pre-pregs stored in refrigerated condi-tions a log shall be carried for each package showing the timeand at which temperature the package has been stored/usedoutside its normal storage conditions.

B 300 Manufacturing premises and conditions301 Manufacturing premises shall be so equipped and ar-ranged that the material supplier’s directions for handling thematerials, the laminating process and curing conditions can befollowed.302 The manufacturing premises shall be free from dust andother contamination that may in any way impair the quality ofthe end product.303 The air temperature in the moulding shops shall not beless than +18°C. The stipulated minimum temperature shall beattained at least 24 hours before commencement of lamination,and shall be maintainable regardless of the outdoor air temper-ature.The temperature in the moulding shop shall not vary more than±5°C. This limit can be exceeded provided it has no detrimen-tal effect on the product and provided there is no risk for con-densation of humidity.304 The relative humidity of the air shall be kept so constantthat condensation is avoided and shall not exceed 80%. A high-er relative humidity can be accepted on a case by case basisprovided an adequate margin against the risk for condensationof humidity is provided. In areas where spray moulding is tak-ing place, the air humidity shall not be less than 40%. The stip-ulated air humidity shall be maintainable regardless of outdoorair temperature and humidity. More stringent requirements tohumidity shall be adhered to if recommended by the manufac-turer.305 Other manufacturing conditions may be accepted basedon special agreement with the Society provided that condensa-

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tion of humidity can be safely avoided.306 Air temperature and relative humidity shall be recordedregularly and the records filed for a period of at least two years.In larger shops there shall be at least one thermohydrograph foreach 1500 m2 where lamination is carried out. The location ofthe instruments shall be such as to give representative meas-urement results.307 Draught through doors, windows etc. and direct sunlightis not acceptable in places where lamination and curing are inprogress.308 The ventilation plant shall be so arranged that the curingprocess is not negatively affected.309 Sufficient scaffoldings shall be arranged so that all lam-ination work can be carried out without operators standing onthe core or on surfaces on which lamination work is takingplace.310 During lamination of larger constructions the tempera-ture shall be recorded at least at two levels vertically in theworkshop and the curing system shall be adjusted to compen-sate for possible temperature differences.311 Prefabrication of panels and other components shall becarried out on tables, fixtures etc. above the shop floor level.No fabrication shall be carried out on the shop floor.

B 400 General requirements to production procedures and workmanship401 Raw materials for all structural members covered by therules shall be of approved type in accordance with Sec.1 B.The supplier’s directions for application of the materials shallbe followed.402 Specified procedures shall be implemented for all taskswith significance to the quality of the end product. Where nec-essary to exercise a satisfactory control of the quality, theseprocedures shall be documented in writing in controlled docu-ments.403 The reference direction of reinforcement shall after be-ing laid not deviate from that specified by more than ±5°.404 Adjacent sheets of reinforcement shall in the normalcase overlap to give structural continuity. The overlap lengthshall be such that the shear capacity of the overlap is not small-er than the tensile strength (perpendicular to the overlap) of theoverlapping plies. The shear strength of the matrix shall not beassumed larger than 8 MPa. A higher shear strength can be as-sumed subject to the approval of the Society. (E.g. for a 0/90°1000 g/m2 type glass reinforcement the overlap shall not besmaller than 30 mm.) In areas of low utilisation, overlaps maybe dispensed with subject to the approval of the Society. Over-laps shall be staggered through the thickness of the laminate.The distance between two overlaps in adjacent plies shall notbe smaller than 100 mm.405 Thickness changes in a laminate shall be tapered over aminimum distance equal to 10 times the difference in thick-ness.406 Thickness changes in core materials shall be taperedover a minimum distance equal to 2 times the difference inthickness. A larger distance may be required to maintain struc-tural continuity of the skins.

B 500 Sandwich lay-up501 Sandwich constructions can be fabricated either by:

— lamination on the core— application of the core against a wet laminate— by bonding the core against a cured skin laminate using a

core adhesive— by resin transfer, i.e. resin transfer moulding of the core to-

gether with one or both of the skin laminates.

502 An efficient bond is to be obtained between the skin lam-inates and the core and between the individual core elements.The bond strength shall not be smaller than the tensile- andshear strength of the core. The application of a light CSM be-tween the core and skin laminate may be advantageous in thisrespect.503 Adequate tools for cutting, grinding etc. of various typesof core material shall be specified in the production procedure.504 All joints between skin laminates and core and betweenthe individual core elements shall be completely filled withresin, adhesive or filler material. The joint gap between coreblocks shall in general not be larger than 3 mm. Larger gapsmay be accepted if necessary, based on the characteristics ofthe adhesive or filler (e.g. its viscosity) and the thickness of thecore. For slamming exposed areas a larger gap width shouldalso be reflected in the qualification testing of the core materialand the adhesive, i.e. during slamming testing.505 Core materials with open cells in the surface, shall nor-mally be impregnated with resin before it is applied to a wetlaminate or before lamination on the core is commenced.506 When the core is applied manually to a wet laminate thesurface shall be reinforced with a chopped strand mat of 450 g/m2 in plane surface and 600 g/m2 in curved surfaces. If vacu-um is applied for core bonding the surface mats may be dis-pensed with provided it is demonstrated in the qualificationtests that an efficient bond between core and skin laminate isobtained.507 If the core is built up by two or more layers of core andany form of resin transfer is used, arrangements shall be madeto ensure proper resin transfer and filling between the coreblocks. This should be achieved by scoring or holing the coreblocks and by placing a reinforcement fabric between the coreblocks to facilitate resin distribution.508 Frameworks for core build up shall give the core suffi-cient support to ensure stable geometrical shape of the con-struction and a rigid basis for the lamination work.509 When a prefabricated skin laminate is bonded to a sand-wich core measures shall be taken to evacuate air from the sur-face between skin and core.510 The core material shall be free from dust and other con-tamination before the skin laminates are applied or core ele-ments are glued together. The moisture content shall besufficiently low not to have any adverse effect on curing. Theacceptable moisture content shall be specified by the manufac-turer of the core material.511 When vacuum-bagging or similar processes are used itshall be ensured that curing in the core adhesive has not beeninitiated before vacuum is applied.

B 600 Manual lamination601 The reinforcement material shall be applied in the se-quence stated on the approved plan(s).602 When the laminate is applied in a mould a CSM of max.450 g/m2 shall be applied next to the gelcoat. The mat can bedispensed with provided a satisfactory resistance against watercan be ensured.603 The resin shall be applied on each layer of reinforce-ment. Gas and air pockets shall be worked out of the laminatebefore the next layer is applied. Rolling of the layers shall bemade carefully, paying special attention to sharp corners andtransitions. The viscosity and gel-time of the resin shall be ad-equate to prevent drain-out of resin on vertical and inclinedsurfaces. The tools and methods used when working the lami-nate shall not damage the fibres.604 The time interval between applications of each layer ofreinforcement shall be within the limits specified by the resinsupplier. For thicker laminates care shall be taken to ensure a

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time interval sufficiently large to avoid excessive heat genera-tion.605 Curing systems shall be selected with due regard to thereactivity of the resin and in accordance with the supplier’srecommendations. Heat release during curing shall be kept at asafe level in accordance with the material manufacturer’s rec-ommendations. The quantity of curing agents shall be keptwithin the limits specified by the supplier.606 After completion of lamination, polyester laminatesshall cure for at least 48 hours at an air temperature of mini-mum +18°C. Curing at a higher temperature and a shorter cur-ing time may be accepted on the basis of control of the curingrate. For other types of resins curing shall be carried out ac-cording to the specified cure cycle and according to the resinmanufacturer’s recommendations.

B 700 Vacuum assisted resin transfer moulding (VARTM) and vacuum-bagging701 Points of resin injection shall be located and opened andclosed in a sequence such that complete filling of the mouldwithout any air being trapped is ensured.702 The resin shall be formulated, based on the resin manu-facturer’s recommendations, such that an adequate viscosityand gel-time is obtained to enable filling of the completemould and such that the maximum temperature during cure iskept within acceptable limits, e.g. with respect to the tempera-ture sensitivity of core materials.703 The pressure level (vacuum) in the mould shall be spec-ified prior to infusion. The pressure shall be adequate to ensureadequate consolidation of the laminate and that the specifiedmechanical properties are reached and that the mould is prop-erly filled. The pressure shall be maintained throughout themould during the cure cycle of the laminate, at least past thepoint of maximum temperature in the laminate, and the speci-fied hold time. The vacuum shall be monitored by the use ofpressure gauges distributed throughout the mould such that areliable indication of the pressure distribution is obtained. Thismeans that pressure gauges shall be placed far away from vac-uum suction points. Adequate means to locate and repair leak-age shall be deployed.

B 800 Spray moulding801 The term spray moulding is understood to mean the si-multaneous deposit of resin and fibreglass reinforcement.Manufacturers using this method are subject to special approv-al.802 When approval of the spray moulding process is consid-ered, special attention will be paid to production arrangement,ventilation equipment, the manufacturer’s own quality controland other factors of significance to the quality of the finishedproduct.803 Spray moulding of structural members shall be carriedout only by specially approved operators.804 The equipment used for spray moulding shall give aneven and homogenous build up of the laminate. Any dosagedevices shall ensure an even application of additives to the pol-yester resin. No fibres shall be shorter than 19 mm.

805 When spray moulding there shall be an even applicationover the entire surface. Regular rolling out of the sprayed-onlayers shall be carried out. Next to the gelcoat rolling out shallbe done for max. 1.5 mm thickness of finished laminate thick-ness, subsequently for at least each 2.5 mm of finished lami-nate thickness. The rolling out shall be done thoroughly toensure adequate compression and removal of gas and air pock-ets. Special care shall be taken at sharp transitions and corners.

B 900 Curing901 Cure cycles shall be documented by temperaturerecords.902 For cure taking place at room temperature in the work-shop the registrations made in the workshop are sufficient todocument the cure cycle.903 For cure at elevated temperature, fans with ample capac-ity shall be operated in the compartment in which the cure iscarried out to ensure an even distribution of temperature. Con-tinuous records of temperature throughout the complete curecycle shall be provided. Recording points shall be distributedthroughout out the length, width and height of the cure com-partment to the extent necessary to verify that the temperaturedistribution is even.

B 1000 Secondary bonding1001 A secondary bonding is defined as any bond betweentwo FRP structures which is made after one or both of the in-dividual structures has effectively cured.1002 The surface ply of a laminate subject to secondarybonding and the first ply of the bonding laminate shall normal-ly be of CSM. This mat can be dispensed with provided thenecessary bond strength is reached.1003 Surfaces in way of secondary bonding shall be cleanand free from dust and other forms of contamination.1004 Laminates on which secondary bonds are to be carriedout shall have an adequate surface preparation, normally in-cluding grinding.1005 If “peel strips” are used in the bonding surface the re-quired surface treatment may be dispensed for.

B 1100 Adhesive bonding1101 Adhesive bonds shall be carried out according to thesame procedure(s) as on which the design and qualificationtesting has been based and according to the recommendationsfrom the manufacturer of the adhesive. Procedure(s) shall besubmitted to the Society prior to commencement of the bond-ing work. The procedure(s) shall give clear requirements to allfactors that can affect the quality of the bond. As a minimumthe following shall be covered:

— working conditions— surface preparation— application— clamp-up— curing cycle etc.

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SECTION 4 THERMOPLASTICS

A. Polyethylene and ABSA 100 General requirements101 The approval is given to the manufacturer who producesthe raw material at the final stage before boat production. Forrotational moulding the approval is granted to the granulate/powder manufacturer. For thermoforming of sheets the ap-proval is granted to the sheet manufacturer.102 Ageing properties shall be verified on sheet materialwith pigments etc. which shall be used in the production.103 The content of pigments shall not exceed 4% and are tobe evenly distributed in the material. Any detrimental effect onthe strength of the material shall be recorded.104 The impact strength of the material at low temperaturesis approved in relation to the fracture character at pendulumnotch impact testing. Brittle fracture at temperatures above0°C shall not be accepted. If the transition between tough andbrittle fracture occurs between 0°C and -20°C, the followingstatement shall be entered on the boat's certificate:The impact strength of the plastic material is reduced at lowtemperatures. The craft is not recommended to be used in coldtemperatures.105 The ability of the material to withstand heating by sun-light is subject to approval on the basis of the reduction in thematerial stiffness between 20°C and 65°C. A reduction in theshear modulus of the material greater than 80% shall not be ac-cepted. If the reduction is between 30% and 80%, the follow-

ing statement shall be entered on the boat's certificate:The material softens at high temperatures and may be perma-nently deformed by long term loading at high temperatures.

A 200 Documentation201 Sec.6 C specifies requirements for properties and docu-mentation.202 The test specimens shall be taken from the materialwhich is used in production, but the material shall not be weak-ened due to the manufacturing process.203 The approval shall state the manufacturing process forwhich the material is approved.

A 300 Properties of polyethylene301 Polyethylene shall comply with the requirements givenin Sec.6 C200. The test specimens shall be taken from materialmanufactured in accordance with a method representative forthe boat production.

A 400 Properties of ABS401 ABS shall comply with the requirements given in Sec.6C300. The test specimens shall be taken from material manu-factured in accordance with a method representative for theboat production.402 The tolerance on the sheet thickness shall not exceed thefollowing:

Figure 1 Tolerance on sheet thickness

403 Tolerance shall be based on measurements at 20 pointsevenly distributed over the width of the sheet. The averagethickness shall not be less than the nominal sheet thickness.

404 Individual values for shrinkage during heating shall notexceed the following:

1 2 3 4 5 6 72,0

3,0

3,5

4,0

4,3

Thickness (mm)

Tole

ranc

e%

±

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Figure 2 Shrinkage during heating

405 The shrinkage of the sheet shall be checked by taking atleast 6 specimens measuring approximately 300 x 300 mmfrom places evenly distributed over the width of the sheet. Oneach specimen the plate direction is to be indicated, and a circleof diameter 100 mm is marked. The specimens are then placed

in talcum powder between metal plates for 30 minutes at aspecified temperature. The metal plates shall have a thicknessof 0.6 to 0.8 mm.

Shrin

kage

(%)

Thickness (mm)8765432

3

4

5

6

7

8

9

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SECTION 5 OTHER MATERIALS

A. Buoyancy materialsA 100 Requirements101 By buoyancy material is meant a low density materiale.g. foam with a specific gravity of less than 1.0, which pro-vides buoyancy to the craft when flooded.102 The water absorption of buoyancy materials shall notexceed 8% by volume after being submerged for 8 days ac-cording to ISO 2896. Material complying with IMO Resolu-tion MSC.81(70) shall be deemed to satisfy this requirement.103 Buoyancy materials shall be resistant to liquids e.g. pet-rol fuel. The requirement may be omitted if the material is to-tally encapsulated when fitted. 104 Results from tests or compliance to Resolution shall bedocumented.

B. Fabrics for RIB collarsB 100 General101 Fabrics for RIB collars shall be selected by the manufac-turer according to the stresses to which the craft is to be sub-jected (shape, dimensions, maximum load, installed poweretc.), and also to the intended service conditions. Use undernormal seagoing conditions shall not materially impair theirperformance.102 Fabrics for RIB collars shall be tested according to ISO6185-3 section 4.2.2. The test results shall be documented.103 RIB collars shall retain their full serviceability withinthe operating temperature range of -20°C to +60°C.

C. Wood C 100 General101 Timber and plywood shall be suitable for the applicationand a marine environment.

102 Timber shall be free from sapwood, resin, cortex, splits,loose knots, insect attacks, rot or other imperfections that willhave an effect on the quality of the material.103 All exposed timber and plywood shall be given weather-tight protection, such as, paint, varnish or preservative, suita-ble for a marine environment.

C 200 Constructional timbers201 Moisture content in constructional timber shall not behigher than 20%. Timber to be bopned by adhesive shall nothave higher moisture content than 15%.202 Constructional timber to be used in hull- and deck-planking and for lamination of frames shall have straightgrains and be quarter sawn.203 Constructional timber shall be stored in dry and wellventilated premises free from direct sunlight. Each piece shallbe stored flat and held apart from other pieces in order to givesatisfactory air circulation.

C 300 Plywood301 Plywood to be used in hull and deck structure shall com-ply with BS 1088, BS 4079 or other equivalent standard.302 The facing veneers shall have a good, solid surface freefrom visible defects.303 Plywood to be used for non-structural application maybe of a lesser quality than stated above, but the adhesive usedshall comply with BS 1203 or equivalent standard.304 Plywood shall be stored flat on a level bed in dry andwell ventilated premises free from direct sunlight

C 400 Adhesives for timber and plywood401 Adhesives shall comply with BS 1204 or other equiva-lent standard.402 Adhesives shall be stored according to the manufactur-er’s recommendation.

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SECTION 6 TABLES OF MATERIAL PROPERTIES

A. Reinforcement fibres, resin and core productsA 100 Properties of Reinforcement Fibres, Resin and Core products101 Minimum mechanical properties are given in the stand-ards that are accepted for certification of the material in ques-tion.

B. Sandwich adhesivesB 100 Un-cured condition

B 200 Cured condition

Table B1 Sandwich adhesives, uncuredProperty Unit Test method Requirement

Density ISO 3521:1990Manufacturer’s nominal value±10%To be given for information.

ViscosityASTM D 1084:1988method B(for free-flowing adhesives)

Manufacturer’s nominal value±20%To be given for information.To be given on works certificate.

Table B2 Sandwich adhesives, cured material

Property Unit Test methodRequired values for approval testing

*) May be required tested at production of the craft

Grade 1 Grade 2Tensile strength, flatwise

MPa

ASTM C 297:1994(specimen: 5x5 cm,speed: 1 mm/min.)

— at 23°C:— at heat resistance

temperature:

≥ 1.0> 80% of Msmv

≥ 1.0> 80% of Msmv

Heat resistance

Temp., °C min.

Percentage retention of ten-sile strength (ASTM C 297-94 specimen: 5x5 cm, speed: 1 mm/min., min. 45°C)after conditioned to heat resistance temperature

45 45Tensile strength and

Fracture elongation

MPa

%

ISO 527:1997(Specimen thickness 4 mm)

— at -10°C— at 23°C— at heat resistance

temperature

Msmv to be given for information

≥ 2.0≥ 3.5≥ 3.5

Msmv to be given for information

≥ 1.0≥ 2.0≥ 2.0

*

*

Shear strength MPa ISO 1922-1981 1) (23°C) ≥ 0.4 ≥ 0.4Overall volume shrinkage % ISO 3521:1997 2) Msmv to be given for

informationMsmv to be given for information

Water resistance % Percentage retention of ten-sile strength (ASTM C 297-94 specimen: 5x5 cm, speed: 1 mm min., 23°C)after 4 weeks in water at 40°C.

≥ 80 ≥ 80

Msmv: Manufacturer’s specified minimum value

1) The test samples are to be made of two pieces of high density core material, preferably PVC foam, with the adhesive located in the mid plane parallel to the steel supports. The adhesive layer shall be > 1 mm thick.

2) Curing shrinkage is relevant for gap filling adhesives only.

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C. Polyethylene and ABSC 100 Properties in general for PE and ABS

C 200 Properties for polyethylene

Table C1 Properties and documentation of PE and ABS

Properties Test method Results to be given for information except where noted.* Also required by delivery

Tensile properties ISO/DIS 527-1985 (Test specimen type 2, 5-50 mm/min.)

Curve at 20°C and 65°C

Shear modulus ISO 537-1980 (torsion pendulum) Curve for temperature range-20°C -65°C

Creep ISO/R 899-1981 (carried out on at least 3 stress levels and 2 test pieces per level)

Isochronous stress-deformation diagram for 1000, 100, 10, 1 and 0.1 hours at 20°C and 65°C

Fatigue Fatigue test carried out with constant stress or deformation amplitude

Curves up to at least 100.000 loading cycles at 20°C *ABS

Hardness ISO 868-1985 (Shore D)

Given at 20°C, read after 15 seconds

Falling weight impact ASTM D 3029-72(method A). The radius of the drop hammer’s striking surface is to be 12.5 mm

Fracture energy by visible crack as fracture criterion, given at 0°C and at 20°C and with relevant material thickness

Pendulum impact With V-notch 45° in accordance with ISO 180-1982. For particularly flexible materials an alternative test method (tensile impact strength) may be used

Fracture energy at 0°C as well as a description of frac-ture type The notch impact strength is only stated for non-aged materials

Ageing ISO 179-1982 (Charpy)without notch: Naturalageing DIN 53386,item 6.1. Acceleratedageing: DIN 53387

Plotted fracture energy for aged materials as a function of logarithmic time. The time is normally to cover 48 months natural ageing or 5 000 hours accelerated age-ing. A shorter time can be approved if the ageing proc-ess is clarified at an earlier stage

Fuel resistance Stressed material submerged in normal en-gine fuel

Description of surface cracking

Melt index ISO 1133-1981 COND 18 To be given for polyethyleneChemical resistance ISO 175-1981 List of chemicals which may damage the materialDensity ISO 1183-1983

(Method D)To be given for polyethylene PE

*Oxygen index ASTM D 2863-1977 Value PE

*

Table C2 Properties of polyethyleneProperty Requirement LDPE Requirement MDPE Unit Comments

Density - 0.930 0.930 - 0.945 g/cm3

Melt index Stated value ±1.0Though max. 3.5

As LDPE g/10 min.

Tensile yield stress

min. 7.5min. 4.5

min. 13.0min. 8.0

N/mm2N/mm2

At 20°CAt 65°C

Elasticity modulus in tensile yield

min. 180 min. 350 N/mm2 At 20°C

Tensile creep strength max. 2.5 at stress 2.0 2.0 at stress 3.0 %N/mm2

Deformation after 100 hours at 20°C

Hardness Stated value ±3 As LDPE Shore D Tested at 20°C and read after 15 sec.

Impact strength (drop test without notch)

min. 15 min. 15 J/mm thickness Freely supported test piece 0°C

Notch impact strength(pendulum test with notch)

Not brittle fracture Not brittle fracture Visual Required only for boats with single skins 0°C

Pore contents max. 15

max. 20

As LDPE

As LDPE

% of thickness% of thickness

In structural partsIn the boat elsewhere

Impact tensile strength of aged material

Not brittle fracturemin. fracture energy

1.0 J/cm3

As LDPE

J/cm2

Visual Aged material corresponding to 4 years of natural ageing, tested at 0°C and with a test speed 2 x 105 %/mm

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C 300 Properties for ABS

Table C3 Properties of ABSProperties Requirements

Tensile yield stress Min. 30 N/mm2 at 20°CMin. 18 N/mm2 at 65°C

Modulus of elasticity Min. 1600 N/mm2 at 20°CCreep Max. 1.0% deformation after 100 hours at a stress of 7.0 N/mm2 at 20°C

Bending fatigue strength At deformation amplitude of 1% and frequency 0.5 Hz the material is to with-stand 50 000 load cycles before fracture

Notch impact strength Min. 2 kJ/m2 at 20°C in accordance with ISO 179-82 (Charpy) without notch

Impact strength (pendulum) of aged material After ageing corresponding to 4 years’ natural ageing, the material is to have a fracture energy of at least 2.5 kJ/m2

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CHAPTER 4

STRUCTURES

CONTENTS PAGE

Sec. 1 Design Principles...................................................................................................................... 41Sec. 2 Design Loads............................................................................................................................ 42Sec. 3 Aluminium and Steel Structural Design................................................................................... 45Sec. 4 FRP Structural Design.............................................................................................................. 51Sec. 5 Thermoplastic Structural Design.............................................................................................. 61

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SECTION 1 DESIGN PRINCIPLES

A. Documentation

A 100 Plans and particulars101 The following plans shall be submitted for approval:

— midship section including main particulars and maximumspeed V

— profile and decks— longitudinal and transversal stiffening members— shell expansion and framing including openings— watertight bulkheads and transom including openings and

their closing appliances — tank structure— engine room structures including foundation for heavy

machinery components— aft peak structures— forepeak structures— superstructures and deckhouses including openings with

sill heights and their closing appliances— hatchways, hatch covers and ports including securing and

tightening appliances— propeller shaft brackets with their attachments to the hull— appendages with their attachments to the hull— rudder and rudder stock with details of bearings and seals— arrangement and particulars of anchoring and mooring

equipment.

Additional documentation may be required.

Guidance note:Identical or similar structures in various positions are recom-mended covered by the same plan.


102 The following plans shall be submitted for information:

— general arrangement— tank arrangements— capacity plan— body plan— arrangement of cathodic protection.

103 Additional documentation required are listed in the ap-propriate sections.

A 200 Strength calculations201 Strength calculations shall normally be submitted forreference to demonstrating that stresses are within requiredlimits.

B. Alternative design standardsB 100 DNV Rules for HSLC and NSC101 For craft with a maximum speed exceeding 45 knots andLWL exceeding 18 m, the DNV Rules for HSLC and NSC shallbe used for determining hull scantlings. Craft with maximumspeed exceeding 45 knots and LWL less than 18 m will be spe-cially considered with respect to hull scantlings.

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SECTION 2 DESIGN LOADS

A. GeneralA 100 Application101 The design loads in this chapter shall only be applied inassociation with the strength formulas given in this chapter.

A 200 Local reinforcements 201 Crafts intended for beaching shall have rubbing stripsand reinforced stem.202 Structure with local loads from cargo, fenders, deck-gears, foundations etc., shall be reinforced for the actual loads.Glass reinforced plastics and wooden crafts shall be reinforcedin areas of local wear.

B. Design loads B 100 Longitudinal strength101 The maximum longitudinal bending moment for craftoperating entirely in displacement mode shall not be taken lessthan:

M = 0.016 · LWL3 · BWL (kNm)

For other craft the maximum longitudinal bending momentshall not be taken less than the larger of:

In no case shall the maximum longitudinal bending moment betaken less than 100 kNm.The maximum longitudinal bending moment shall be appliedto the central 25% of L with a linear reduction to zero at thefore and aft end of the craft.

B 200 Sea pressure on hull bottom201 The design sea pressure, Pb, acting on the hull bottomshall not be taken less than:

Pb = PFb · klb · kβ · ka (kN/m2)

PFb = pressure factor taken from fig. belowV = max. speedklb = longitudinal distribution of sea pressure, to be taken

from figures below. Intermediate values to be found byinterpolation

kβ = correction for deadrise angle applicable to crafts withspeed V > and length L > 9 m, taken from the fig-ure below. The deadrise angle shall not be taken great-er than 22 degrees

ka = area reduction factor considering the size of the designarea, Ad, relative to the reference area Ar, to be takenfrom the figure below

Ad = s2 (m2) for plates and panels

Ad = s · l (m2) for frames/stiffenersAr = 0.2 · L· B (m2)s = shortest panel edge or load breadth for stiffening mem-

bers in metresl = span length of stiffening members in metres.

1) M = 0.016 · LWL3 · BWL (kNm)

2) M = 0.0025 · Δ · LWL (kNm)

3 L

0

50

100

150

200

250

300

350

10 15 20 25 30 35 40 45

V (knots)

PFb

3 m

6 m

24 m

9 m

12 m

15 m

18 m

21 m

L=

0.50

0.60

0.70

0.80

0.90

1.00

0 0.25 0.5 0.75 1

x Lh

klb

V/ Lh=> 6

4

< 3

5

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202 The vertical extension of the design sea pressure, Pb,shall be as follows:

— up to the deepest w.l. for crafts with V ≤ 3— up to the chine for crafts with V > 3

B 300 Sea pressure on hull side301 The design sea pressure acting on the hull side shall not

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

12 14 16 18 20 22

Deadrise angle amidship

kβ

24 m

21 m

9 m

6 m

3 m

12 m

15 m

18 m

L=

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.001 0.01 0.1 1Ad/Ar

ka

LL

DWL

V ≤ 3√L

DWL

V ≤ 3√L

DWL

V > 3√L

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be taken less than:Ps = PFs · kls · kv · ka (kN/m2)

PFs = pressure factor taken from figure belowV = max. speedkls = longitudinal distribution factor to be taken from the

figure below

kv = for vertical distribution factor

= minimum 0.5 for design category A and B.

h = distance from side/bottom transition to the load point (m)PFs, F, h and kv are shown on the figures below. B 400 Design loads on decks and superstructures

401 The design sea pressure acting on decks shall not be tak-en less than:

Pd = kd · L + 4.5 (kN/m2) kd = 0.2 for exposed main weather deck and superstructure

deck forward of 0.25 L from FP = 0.1 for exposed superstructure decks elsewhere.

402 The design load for accommodation decks and decks in-tended for cargo shall be taken as:

H = deck cargo in t/m2

= 0.35 t/m2 for accommodation decks.

403 The design sea pressure on superstructures and deckhouses shall not be taken less than given in the table below:

B 500 Design loads for bulkheads and tanks501 The design load for watertight bulkheads shall not betaken less than:

Pbh = 10 · hb (kN/m2)hb = distance from load point to top of bulkhead.

502 The design load for tanks for oil, freshwater, water bal-last, etc. shall not be taken less than:

pt = 7 · ht (kN/m2)= min. 15 (kN/m2)

ht = distance from load point to top of air pipe or fillingpipe whichever is the greater.

B 600 Miscellaneous equipment601 The interface between the waterjet and the hull shall bedesigned for the reaction forces in the jet and the design pres-sure at the location.

Fv h–Fv

--------------

Fv4.5Δ

1000LB--------------------=

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

160.00

180.00

10 15 20 25 30 35 40 45V (knots)

PFs

3 m

6 m

24 m

9 m

12 m

15 m

18 m

21 m

L=

0.50

0.60

0.70

0.80

0.90

1.00

0 0.25 0.5 0.75 1

x Lh

kls

Position p (kN/m2)Front bulkheadSides and aft bulkheadDeck house roof, 1st tierDeck house roof, elsewhere

0.3 L + 6 0.15 L + 30.1 L + 30.1 L + 1.5

Pdc 10 H 1 0.2 VL

-------+⎝ ⎠⎛ ⎞=

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SECTION 3 ALUMINIUM AND STEEL STRUCTURAL DESIGN

A. GeneralA 100 Structural aluminium material101 The scantling requirements are based on a correctionfactor f1 for material strength. f1 shall be taken according to thefollowing tables:

102 The scantling requirements in this section are based onthe properties of aluminium material as fabricated (no defor-mation hardening) with minimum properties in accordancewith the tables below.

*) Applies to welded condition.

Table A1 Factor f1 for wrought aluminium alloy sheets, strips and plates, t: 2 mm ≤ t ≤ 40 mm

DNVDesignation

Temper f1

NV-5052 H32 H34

0.61 0.69

NV-5154A 0, H111 0.35NV-5754 H24 0.69NV-5454 H32

H340.73 0.79

V-5086 H116, H32 H34

0.80 0.88

NV-5083 H116, H321 0.89NV-5383 H116, H34 0.89

Note: For tempers 0 and H111, the factor f1 is to be taken from Table A4.

Table A2 Factor f1 for extruded aluminium alloy profiles, rods and tubes, t: 2 mm ≤ t ≤ 25 mm

DNVDesignation

Temper f1

NV-6060 T5 0.55NV-6061 T4

T5/T60.46 0.76

NV-6063 T5 T6

0.44 0.60

NV-6005A T5/T6 0.76NV-6082 T4

T5/T60.46 0.90

Note: Table A2 only applies when the main loading direction is lon-gitudinal to the extrusion, see also Table A3.

Table A3 Factor f1 for extruded aluminium alloy profiles, rods and tubes, t: 2 mm ≤ t ≤ 25 mm, transverse to extruding direction

DNVDesignation

Temper f1

NV-6060 T5 0.51NV-6061 T4

T5/T60.46 0.71

NV-6005A T5/T66 < t < 1010 < t < 25

0.760.67

NV-6082 T5 / T6 0.85

Table A4 Factor f1 in the welded conditionDNV

DesignationTemper Filler f1

NV-5052 0, H111, H32, H34 5356 0.27NV-5154A 0, H111 5356-5183 0.35NV 5754 0, H111, H24 5356-5183 0.33NV 5454 0, H111, H32, H34 5356-5183 0.35NV-5086 0, H111, H116, H32,

H345356-5183 0.42

NV-5083 H116, H321 H116, H321

5356 5183

0.53 0.60

NV-5383 H116, H34 5183 0.64NV-6060 T5 5356-5183 0.27NV-6061 T4

T5/T65356-5183 0.48

0.48NV-6063 T5

T65356-5183 0.27

NV-6005A T5/T6 5356-5183 0.48NV-6082 T4

T5/T65356-5183 0.46

0.48

Table A5 Mechanical properties of wrought aluminium alloy sheets, strips and plates 2 mm ≤ t ≤ 40 mm

Alloy Tensile strength (N/mm2)

Yield strength *) (N/mm2)

5052 170 655154A 215 855754 190 805454 215 855086 240 955083 275 1255383 290 145

Table A6 Mechanical properties for extruded aluminium alloy profiles, rods and tubes 2 mm ≤ t ≤ 25 mm

Alloy Temper Tensile strength (N/mm2)

Yield strength (N/mm2)

6060 T5 or T6 190 150

6061T4 180 110

T5 or T6 260 240

6063T5 150 110T6 205 170

6005A T5 or T6 260 215

6082T4 205 110

T5 or T6 310 260

Table A7 Mechanical properties for closed extruded aluminium alloy profiles, rods and tubes, 2 mm ≤ t ≤ 25 mm, Transverse to extrusion direction

Alloy Temper Tensile strength (N/mm2)

Yield strength (N/mm2)

6060 T5 175 135

6061T4 165 110

T5 or T6 245 205

6005AT5 or T6

6 mm < t < 10 mm 260 21510 mm < t < 25 mm 230 195

6082 T5 or T6 290 240

Table A4 Factor f1 in the welded condition (Continued)DNV

DesignationTemper Filler f1

DET NORSKE VERITAS


A 200 Structural steel201 The scantling requirements are based on the correctionfactor f1 for material strength. f1 shall be taken according to thefollowing table:

B. Structural arrangementB 100 Structural design in general101 The ship arrangement shall take into account:

— continuity of longitudinal strength, including horizontalshear area to carry a strength deck along

— transverse bulkheads or strong webs— web/pillar rings in engine room— superstructures and deckhouses— direct support— transitions— deck equipment support— multi-deck pillars in line, as practicable— external attachments, inboard connections.

102 Brackets are to extend to the nearest stiffener, or localplating reinforcement shall be provided at the toe of the brack-et.103 Generally, connections of outfitting details to the hullshall be such that stress-concentrations are minimized andwelding to high stressed parts is avoided as far as possible.104 Connections shall be designed with smooth transitionsand proper alignment with the hull structure elements. Termi-nations shall be supported.105 Connections to top flange of girders and stiffeners shallbe avoided if not well rounded. Preferably, supporting of out-fitting shall be welded to the stiffener web.106 The effective span of a stiffener (l) or girder (s) dependson the design of the end connections in relation to adjacentstructures. Unless otherwise stated the span points at each endof the member, between which the span is measured, shall bedetermined as shown on the following figure. It is assumed thatbrackets are effectively supported by the adjacent structure.

B 200 Global strength201 The section modulus of hull girder shall not be less than:

along the central 25% of the length of the hull girder. Outsidethe central part, the section modulus may be reduced linearlyto zero at the fore and aft end of the craft.202 The effective sectional area of continuous longitudinalstrength members is in general the net area after deduction ofopenings.Superstructures which do not form a strength deck are not to beincluded in the net section. This applies also to deckhouses andbulwarks.The effect of openings is assumed to have longitudinal exten-sions as shown by the shaded areas in the figure below i.e. in-side tangents at an angle of 30° to each other. Example fortransverse section III:

BIII = b’ + b’’ + b’’’For twin hull crafts the effective breadth of wide decks withoutlongitudinal bulkhead support will be considered.

Table A8 Factor f1 for steel materialMinimum yield strength

(N/mm2) f1235 1.00265 1.13315 1.34355 1.51390 1.66

Z 6250 Mf1----- (mm3 )=

DET NORSKE VERITAS


B 300 Bottom structures301 The bottom structure shall comply with the requirementsgiven in C and D. The local strength of the keel shall be suffi-cient to withstand loads in connection with docking attachmentof external ballast keel, etc.302 Bottom structures may be longitudinally or transverselystiffened.303 In planing craft single bottom as well as double bottomsare normally to be longitudinally stiffened. 304 The longitudinal shall preferably be continuous throughtransverse members. If they are to be cut at transverse mem-bers, i.e. watertight bulkheads, continuous brackets connectingthe ends of the longitudinal shall be fitted or welds shall be di-mensioned accordingly.305 Longitudinal stiffeners shall be supported by bulkheadsand web frames.306 Displacement crafts with single bottom and transverseframes shall have floors at each frame. The floors shall be con-tinuous from side to side.307 Web frames are to be continuous around the cross sec-tion i.e. floors side webs and deck beams are to be connected.Intermediate floors may be used.308 In the engine room plate floors shall be fitted at everyframe. In way of thrust bearings additional strengthening shallbe provided.309 Longitudinal girders shall be carried continuouslythrough bulkheads. In craft built in sandwich construction lon-gitudinal girders may be fitted to support the bottom panels.310 A centre girder shall be fitted for docking purpose if theexternal keel or bottom shape does not give sufficient strengthand stiffness.311 Openings shall not be located at ends of girders withoutdue consideration being taken to shear loadings.312 Under the main engine, girders extending from the bot-tom to the top plate of the engine seating shall be fitted.313 Engine holding down bolts shall be arranged as near as

practicable to floors and longitudinal girders.314 In way of thrust bearing and below pillars additionalstrengthening shall be provided.315 Manholes shall be cut in the inner bottom, floors andlongitudinal girders to provide access to all parts of the doublebottom. The vertical extension of lightening holes shall not ex-ceed one half of the girder height. The edges of the manholesshall be smooth. Manholes in the inner bottom plating shallhave reinforcement rings. Manholes shall not be cut in thefloors or girders in way of pillars.316 In double bottoms with longitudinal stiffening, thefloors shall be stiffened at every bottom longitudinal.317 In double bottoms with transverse stiffening, longitudi-nal girders shall be stiffened at every transverse frame.318 The longitudinal girders shall be satisfactorily stiffenedagainst buckling.

B 400 Side structures401 The scantlings of side structures shall comply with therequirements given in C and D.402 The craft’s sides may be longitudinally or verticallystiffened.403 The continuity of longitudinal shall be as required forbottom and deck longitudinal respectively.404 Vertical side frames shall normally be connected tofloors and deck beams with well rounded transitions and a con-tinuous flange laminate.

B 500 Deck structure501 The scantlings of deck structures shall comply with therequirements given in C and D.502 Decks may be longitudinally or transversely stiffened.503 Longitudinal shall preferably be continuous throughtransverse members. If they are to be cut at transverse mem-bers, i.e. watertight bulkheads, continuous brackets connectingthe ends of the longitudinal shall be fitted.504 The plate thickness shall be such that the necessarytransverse buckling strength is achieved, or transverse buck-ling stiffeners may have to be fitted intercostals.505 The thickness of bulwark plates shall not be less than re-quired for side plating in a superstructure in the same position. 506 A strong section shall be continuously welded to the up-per edge of the bulwark. Bulwark stays shall be in line withtransverse beams or local transverse stiffening. The stays shallhave sufficient width at deck level. The deck beam shall becontinuously welded to the deck in way of the stay. Bulwarkson forecastle decks shall have stays fitted at every frame507 Stays of increased strength shall be fitted at ends of bul-wark openings. Openings in bulwarks shall not be situated nearthe ends of superstructures.508 Where bulwarks on exposed decks form wells, ampleprovision shall be made to freeing the decks for water.

B 600 Bulkhead structure601 The scantlings of bulkhead structures shall comply withthe requirements given in C and D.602 Number and location of transverse watertight bulkheadsshall be in accordance with the requirements given for the var-ious craft types.603 The stiffening of the upper part of a plane transversebulkhead shall be such that the necessary transverse bucklingstrength is achieved.604 Longitudinal and transverse bulkheads may be corrugat-ed.

DET NORSKE VERITAS


For corrugated bulkheads the following definition of spacingapplies (see figure below):

s = s1 for section modulus calculations = 1.05 s2 or 1.05 s3 for plate thickness calculations.

605 Bulkheads supporting decks shall be regarded as pillars.The compressive loads and buckling strength shall be calculat-ed as indicated in E assuming:

i = radius of gyration in cm of stiffener with adjoiningplate. Width of adjoining plate shall be taken as 40 t,where t = plate thickness.

Local buckling strength of adjoining plate and torsional buck-ling strength of stiffeners shall be checked in accordance withE.

B 700 Superstructures and deckhouses701 The scantlings of superstructures and deckhouses shallcomply with the requirements of C and D.702 In superstructures and deckhouses, the front bulkheadshall be in line with a transverse bulkhead in the hull below orbe supported by a combination of girders and pillars. The afterend bulkhead shall be effectively supported. As far as practica-ble, exposed sides and internal longitudinal and transversebulkheads shall be located above girders and frames in the hullstructure and shall be in line in the various tiers of accommo-dation. Where such structural arrangement in line is not possi-ble, there shall be other effective support.703 Sufficient transverse strength shall be provided bymeans of transverse bulkheads or girder structures.704 At the break of superstructures, which have no set-infrom the ship’s side, the side plating shall extend beyond theends of the superstructure, and shall be gradually reduced inheight down to the deck or bulwark. The transition shall besmooth and without local discontinuities. A substantial stiffen-er shall be fitted at the upper edge of plating. The plating shallbe additionally stiffened.705 In long deckhouses, openings in the sides shall have wellrounded corners. Horizontal stiffeners shall be fitted at the up-per and lower edge of large openings for windows.706 Openings for doors in the sides shall be substantiallystiffened along the edges. The connection area between deck-house corners and deck plating shall be increased locally.707 Deck girders shall be fitted below long deckhouses inline with deckhouse sides.708 Deck beams under front and aft ends of deckhouses shallnot be scalloped for a distance of 0.5 m from each side of thedeckhouse corners.709 For deckhouse side stiffeners the scantlings may not begreater than required for twin deck frames with equivalent endconnections.710 Casings supporting one or more decks above shall be ad-equately strengthened.

C. Steel and aluminium platingC 100 General101 In this section the general requirements for the localstrength of laterally loaded plates are given.

C 200 Plate thickness201 Plate thicknesses shall be not less than the largest valuefound from the following formulae:

tp = 1.7 fp s + tc (mm)

t0 and k are given in the tables in 202.fp is given in 203.

tc = corrosion allowance for steel constructions as given forthe respective type and service notations. To be taken aszero for aluminium constructions.

202 t0 and k are to be taken from the tables below:

, for open craft

Table C1: ALUMINIUMItem L ≤ 15 m L > 15 m

t0 k t0 kHull bottom 1.5 0.23 · kv 4.3 0.04Hull side 1.0 0.23 3.8 0.04Transom, not supporting engine

1.0 0.23 3.8 0.04

Exposed deck, cargo deck 0.8 0.21 + 0.21 · H 3.7 0.03

Accommoda-tion deck 0.8 0.21 3.5 0.03

Superstruc-tures and deckhouses

0.4 0.21 3.1 0.03

Structural/watertight bulkheads

0.4 0.21 3.1

Table C2: STEELItem L ≤ 15 m L > 15 m

t0 k t0 kHull bottom 1.0 0.23 · kv · kd 3.8 0.04Hull side 0.5 0.2 · kd 3.3 0.04Transom, not supporting engine

0.5 0.23 3.3 0.04

Exposed deck, cargo deck 0.3 0.21 + 0.1 · H 3.2 0.03

Accommoda-tion deck 0.3 0.21 2.0 0.03

Superstruc-tures and deckhouses

0 0.21 2.7 0.03

Structural/watertight bulkheads

0 0.21 2.7 0.03

tmin t0 kL 1f1

-------- tc (mm)+ +=

P

5.1)12( BLkd ⋅⋅

Δ=

DET NORSKE VERITAS


kv = 0.86 + 0.014 VH = deck cargo (ton/m2)

203 The combined correction factor fp is given by:

f1 as defined in Sec.1 B103 and C103.The aspect ratio correction factor, f2, is to be taken as:

f2 = (1.1 – 0.25 s/l)2

= max. 1.0 = min. 0.72.The correction factor, f3, for plate curvature is to be taken as:

f3 = 1 - h/s = minimum 0.8.h and s are defined in the figure below.

D. Frames, girders and stiffeners

D 100 General101 In this section the general requirements for the strengthof laterally loaded frames, beams and other stiffeners in steeland aluminium constructions are given.

D 200 Section modulus201 The section modulus of stiffening members is not to beless than:

m = values for the most common structural members arefound in the table in 203.

b = load breadth in metresl = stiffener span in metres. For curved frames see 202.f1 as defined in A.202 For concave frames the length which determines thescantlings is given by:

l = l0 – 3 f + 0.3 R metres

l0 = length in metres of the straight part of the frame in bot-tom. When the bilge radius is constant, is measured asshown in Fig.1. When the radius varies, is measured asshown in Fig. 2 below.

R = bilge radius in metres.For S-shaped frames the length which determines scantlings ismeasured as shown in the figures below.

Figure 1

Figure 2

Figure 3

Figure 4

203 The m-values are normally to be taken as follows for the

fpf2f3f1

---------=

W 6.25 mPbl2

f1----------------10 3– (cm3 )=

DET NORSKE VERITAS


various structural members:

204 The formula given in 201 is to be regarded as the re-quirement about an axis parallel to the plating. As an approxi-mation the requirement to standard section modulus forstiffeners at an oblique angle with the plating may be obtainedif the formula in 101 is multiplied by the factor:

α = angle between the stiffener web plane and plane per-pendicular to the plating.

For angles α < 15° corrections are normally not necessary.205 When several members are equal, the section modulusrequirement may be taken as the average requirement for eachindividual member in the group. However, the requirement forthe group is not to be taken less than 90% of the largest indi-vidual requirement.206 Effective plate flange may normally be taken equal tothe stiffener spacing.207 The thickness of web and flange is not to be less than:for flats: tweb = 1/15 x flat depth.for other sections: tweb = 1/50 x web depth, provided net shear area > 0.075 lsptflange = 1/15 x flange width from web.

E. PillarsE 100 General101 In this section the general requirements to steel pillarssupporting structure or equipment are given.102 Where practicable, deck pillars are to be located in linewith pillars above or below. Otherwise beams or girders indeck in way will have to be reinforced.

E 200 Scantlings201 Solid steel pillars shall have dimensions according to thetable below:

202 Tubular pillars shall have dimensions according to thetable below, based on the scantlings of solid pillars:

Table D1 m-valuesItem m

Continuous longitudinals 85Non-continuous longitudinals 100Transverse 100Vertical members, ends fixed 100Vertical members, simply supported 135Bottom longitudinal 85Bottom transverse 100Side longitudinal 85Side vertical 100Deck longitudinal 85Deck transverse 100W.T. bulkhead, fixed ends 65W.T. bulkhead, fixed one end 85W.T. bulkhead, simply supported ends 125Tank and cargo bulkheads, fixed ends 100Tanks and cargo bulkheads, simply supported ends 135Deckhouse stiffener 100Casings 100

1αcos

------------

Table E1 Solid steel pillars

Load (kN)Pillar length (m)

2.0 2.5 3.0 3.5Diameter (mm)

30 50 53 56 5940 53 56 60 6460 56 60 65 6980 59 64 69 73100 62 68 73 78130 65 71 77 82160 68 75 81 86200 71 78 84 90240 74 81 88 94290 77 84 91 98340 80 88 95 102400 83 91 99 106

Table E2 Tubular steel pillarsDiameter of equiv. solid pillar (mm)

Pillar length (m)

2.0 2.5 3.0 3.5

50 70x6.0 70x6.0 70x6.055 70x6.0 70x6.0 70x6.060 80x6.5 75x6.0 75x6.0 75x6.065 90x6.5 80x6.5 80x6.5 80x6.070 100x7.0 90x6.5 90x6.5 89x6.575 115x7.0 110x6.5 110x6.5 100x6.580 130x7.5 120x7.0 115x7.0 105x6.585 145x8.0 130x7.5 125x7.0 115x7.090 160x8.5 145x8.0 135x7.5 125x7.0

DET NORSKE VERITAS


SECTION 4 FRP STRUCTURAL DESIGN

A. GeneralA 100 Application101 The requirements in this section apply to fibre rein-forced plastic (FRP) single skin and sandwich constructions.102 Additional or modified requirements may be given in as-sociation with the various type and service notations.103 Alternative scantling determination methods may be ac-cepted upon consideration in each individual case.

A 200 Assumptions201 A single skin construction is considered to be a structureconsisting of a FRP shell laminate supported and stiffened lo-cally by a system of closely spaced FRP stiffeners.202 A sandwich construction is considered to be structuralelement consisting of three components: A FRP skin laminateon each side of a low density core. It is assumed that the prop-erties and the proportions of the component materials are suchthat when a sandwich panel is exposed to a lateral load thebending moments are carried by the skins and the shear forcesby the core. The condition for compliance with this assumptionis given in D. It is further assumed that an efficient bond be-tween skins and core is obtained.

A 300 Definitions301 The following symbols are applied:

σnu = breaking strength of FRP laminate in tension or com-pression in MPa

En = modulus of elasticity of FRP laminate in tension orcompression in MPa

σbu = breaking strength in bending of FRP laminate in MPaEb = modulus of elasticity in bending of FRP laminate in

MPaτu = breaking strength in shear of sandwich core material in

MPafn = correction factors for strength

fb = correction factors for strength, bending

t = laminate thickness in mm, either for a single skin plateor a sandwich skin laminate

s = shortest panel edge for single skin and sandwich panelsb = load breadth for stiffening members in metresl = span length of stiffening members in metres.

A 400 Calculation methods401 To determine stresses and deflections in FRP single skinand sandwich constructions either direct calculations using thefull stiffness and strength properties of the laminate in all di-rections or a simplified method in accordance with C, D and Ewill be accepted.402 The simplified method may be employed on the follow-ing conditions:

— the principal directions of the laminate reinforcement areparallel to the panel edges

— the difference in elastic modulus in the two principal di-rections is not more than 20%

— the skin laminates of sandwich panels are thin, i.e. d/t > 5.77.

403 Direct calculations based on the full strength and stiff-ness properties in all directions shall be carried out in accord-

ance with the procedures given in the Rules for Classificationof High Speed and Light Craft.

A 500 Structural design in general501 Attention is drawn to the importance of structural conti-nuity in general.502 The structural arrangement shall take into account:

— continuity of longitudinal strength, including horizontalshear area to carry a strength deck along

— transverse bulkheads or strong webs— web/pillar rings in engine room— twin hull connections— superstructures and deckhouses:

— direct support— transitions

— deck equipment support— multi-deck pillars in line, as practicable— external attachments, inboard connections.

503 Corners and dimensional transitions shall be well round-ed to avoid stress concentrations.504 Tensile loads perpendicular to the plan of the laminateshould be avoided.505 Thickness differences in laminates should be taperedover a length of at least 20 x thickness difference.506 Overlap between layers of reinforcement shall be suchthat the in-plane shear strength of the joint is at least equal tothe axial strength of the reinforcement. for most standard rein-forcements this is achieved with an overlap of 40 mm.507 In bolt and rivet connections the distance from the lam-inate edge to the centre of the hole shall be 3.0 x and 2.5 x holediameter respectively.508 Distance between rivets shall be at least 2.5 x hole diam-eter and for bolts at least 3.0 x hole diameter. Bolts and rivetsshall normally be fitted with washers with diameter 2.0 x holediameter in both ends.

A 600 Materials601 Structural materials shall be approved by the Society.

A 700 Mechanical properties of laminate701 The requirements for structural laminates are based onthe following minimum mechanical properties:

702 The mechanical properties used for the scantling deter-mination shall normally be derived from tests, these tests shallbe conducted in accordance with the International Standardsgiven below.703 The test specimen shall be representative of the productas manufactured.704 The mean value of the results from the tests shall complywith the requirements given in 701. No single value shall beless than 80% of the value used as basis for determination ofscantlings.705 The mechanical properties used in the calculations shall

80σnu---------

130σbu---------

Tensile strength, σnu = 80 MPaTensile modulus, En = 7000 MPaBending strength, σbu = 130MpaBending modulus, Eb = 6000 Mpa.

DET NORSKE VERITAS


be:

— for strength, 90% of the mean ultimate strength— for elastic modulus, the mean value.

706 The fibre content by mass shall be at least 27% measuredin accordance with ISO 1172. All individual test result valuesare to comply with the specified requirements.707 Tensile strength, σn , and modulus, En , is determined inaccordance with ISO 527. The test specimens should be takenin both directions.708 Flexural strength, σb , and modulus, Eb , is determined inaccordance with ISO 178. The test specimens should be takenin both directions.

A 800 Mechanical properties of sandwich core materials801 For hull structural applications core material of Grade 1is required. For other applications Grade 2 may be accepted.802 It shall be verified by shear testing in accordance withISO 1922 or ASTM C 273-61 that the bonds between skin andcore and between individual core elements have at least thesame shear strength as specified for the core material in ques-tion.803 The shear strength and modulus of core materials are tobe specified and verified by testing in accordance with theabove standards.804 It shall be verified by four point sandwich beam bendingtests in accordance with ASTM C 393 that the applied corebonding adhesive does not crack or de-bond at a lower loadlevel than the core materials itself.805 The testing is normally to be carried out at 20°C, if con-sidered necessary the testing may be required to be carried outat other representative operating temperatures.

A 900 Global strength901 The section modulus of the hull girder shall not be lessthan:

Z = 38 000 · fn · M (mm3)along the central 25% of the length of the hull girder. Outsidethe central part, the section modulus may be reduced linearlyto zero at the fore end and aft end of the craft.902 When calculating the moment of inertia and sectionmodulus of the mid ship section, the effective sectional area ofcontinuous longitudinal strength members is in general the netarea after deduction of openings.903 Superstructures which do not form a strength deck arenot to be included in the net section. This applies also to deck-houses and bulwarks.904 The effect of openings is assumed to have longitudinalextensions as shown by the shaded areas in Fig. 1 i.e. insidetangents at an angle of 30° to each other. Example for trans-verse section III:

bIII = b’ + b’’ + b’’’

Figure 1 Effect of openings

905 For twin hull crafts the effective breadth of wide deckswithout longitudinal bulkhead support will be considered.

B. Structural arrangementB 100 Bottom structures101 The bottom single skin or sandwich panels shall complywith the requirements given in C and D. The local strength ofthe keel shall be sufficient to withstand loads in connectionwith docking attachment of external ballast keel, etc.102 Bottom structures may be longitudinally or transverselystiffened.103 In planning craft single bottom as well as double bot-toms shall normally be longitudinally stiffened in single skinconstructions. In craft with sandwich construction transversestiffening may be accepted.104 The longitudinal should preferably be continuousthrough transverse members. At their ends longitudinal are tobe fitted with brackets or to be tapered out beyond the point ofsupport.105 Longitudinal stiffeners are to be supported by bulkheadsand/or web frames.106 Displacement crafts with single bottom and transverseframes shall have floors at each frame. The floors shall be con-tinuous from side to side. The scantlings of the floors may betaken in accordance to Table B1, with notes. The table valuesare applicable when the distance between transverse bulkheadsor other equivalent support for the longitudinal girders doesnot exceed the breadth of the craft. If the girder span is greaterthan the breadth of the craft, the floors web plate height andflange area shall be increased as stated in the table's note. Al-ternatively, the scantlings of the floors shall be established inaccordance with subsection E.

DET NORSKE VERITAS


107 Longitudinal girders are to be carried continuouslythrough bulkheads. In craft built in sandwich construction lon-gitudinal girders may be fitted to support the bottom panels.108 A centre girder is to be fitted for docking purpose if theexternal keel or bottom shape does not give sufficient strengthand stiffness.109 Openings should not be located at ends of girders with-out due consideration being taken to shear loadings.110 The scantlings of longitudinal girders may be taken inaccordance with Table B2 or alternatively according to E.111 Main engines are to be supported by longitudinal girderswith suitable local reinforcement to take the engine and gearmounting bolts. Rigid core materials to be applied in allthrough bolt connections.112 Web frames are to be continuous around the cross sec-tion of the craft, i.e. web- and flange laminates of floors, sidewebs and deck beams are to be efficiently connected together.If intermediate floors are fitted, their ends should be well ta-pered or connected to local panel stiffening.113 In the engine room, floors shall be fitted at every frame.The floors are preferably to be carried continuously throughthe engine girders. In way of thrust bearings additionalstrengthening must be provided. 114 In double bottoms manholes are to be made in the innerbottom, floors and longitudinal girders to provide access to allparts of the double bottom. The vertical extension of openingsshall not exceed one half of the girder height. Exposed edgesof openings in sandwich constructions shall be sealed with res-in impregnated mat. All openings shall have well rounded cor-ners.115 Crafts built in sandwich construction and with:

shall have the fore stem designed so that a local impact at orbelow the waterline will not result in skin laminate peeling dueto hydraulic pressure. The vertical extension of the collisionprotection shall be from the keel to a point 0.03 L (m) abovethe waterline at operating speed.

B 200 Side structures201 The hull sides may be longitudinally or vertically stiff-ened. The continuity of longitudinal is to be as required for bot-tom and deck longitudinal respectively.202 The single skin or sandwich panels of the hull sides shallcomply with the requirements of subsections C and D.203 Vertical side frames shall normally be connected tofloors and deck beams with well rounded transitions and a con-tinuous flange laminate.

B 300 Transom structure301 The scantlings of transom not subjected to loads fromengine or rudder installations shall comply with the require-ments of C and D.302 Trust bearing transom for outboard engine or stern drivemounting is preferable to be built as a sandwich panel with acore of waterproof plywood or equivalent material. The thick-ness of the transom for engine power specified by the manu-

facturer, should not be less than given in the following table:

303 The inner laminate on the core is normally to have athickness not less than 0.7 times the thickness of the side lam-inate, and the outer laminate a thickness not less than 0.7 of thebottom laminate. The inner laminate shall extend forwardalong the sides and the bottom of the boat, and shall be gradu-ally tapered in thickness.

B 400 Deck structure401 Decks may be longitudinally or transversely stiffened.402 Deck panels of single skin or sandwich constructionshall comply with the requirements of C and D.403 Longitudinal should preferably be continuous throughtransverse members. At their ends longitudinal are to be fittedwith brackets or be tapered out beyond the point of support.404 Bulwark sides are considered to be a part of the hull sideand shall have scantlings accordingly. A strong flange is to bemade along the upper edge of the bulwark. Bulwark stays areto be arranged in line with transverse beams or local stiffening.The stays are to have sufficient width at deck level. If the deckis of sandwich construction, solid core inserts are to be fitted atthe foot of the bulwark stays. Stays of increased strength are tobe fitted at ends of bulwark openings. Openings in bulwarksshould not be situated near the ends of superstructures.

B 500 Bulkhead structures501 The scantlings of bulkhead structures shall comply withthe requirements of C and D.502 Number and location of transverse watertight bulkheadsare to be in accordance with the requirements given for the var-ious craft types specified in Ch.2 Sec.1.503 Bulkheads supporting decks are to be regarded as pillars.The buckling strength will be considered in each individualcase.

B 600 Superstructures and deckhouses601 The scantlings of superstructures and deckhouses shallcomply with the requirements of subsections C and D. 602 Superstructure is defined as a decked structure on thefreeboard deck, extending from side to side of the ship of withthe side plating not inboard of the shell plating more than 4%of the breadth (B).603 Deckhouse is defined as a decked structure above thestrength deck with the side plating being inboard of the shellplating more than 4% of the breadth (B).604 Long deckhouse - deckhouse having more than 0.2 L, ofits length within 0.4 L amidships.605 Short deckhouse - deckhouse not defined as a long deck-house.

VL

------- 4.5>

Table B1: Thrust bearing transom

Engine pow-er(kW)

Total thickness of transom (mm)

Outboard mounting Stern drive mounting

< 3 12 17

3 - 7 15 20 7 - 18 25 3018 - 30 30 35

30 - 60 35 40

60 - 95 40 45

> 95 Scantlings to be specially considered in each in-dividual case.

DET NORSKE VERITAS


606 In superstructures and deckhouses, the front bulkhead isto be in line with a transverse bulkhead in the hull below or besupported by a combination of girders and pillars. The afterend bulkhead is also to be effectively supported. As far as prac-ticable, exposed sides and internal longitudinal and transversebulkheads are to be located above girders and frames in thehull structure and are to be in line in the various tiers of accom-modation. Where such structural arrangement in line is notpossible, there is to be other effective support.607 Sufficient transverse strength shall be provided bymeans of transverse bulkheads or girder structures. 608 At the break of superstructures, which have not set-infrom the ship's side, the side plating is to extend beyond theends of the superstructure, and be gradually reduced in heightdown to the deck or bulwark. The transition shall be smoothand without local discontinuities. 609 In long deckhouses, openings in the sides shall have wellrounded corners. In deckhouses of single skin constructionhorizontal stiffeners shall be fitted along the upper and loweredge of large openings for windows. Openings for doors in thesides shall be substantially stiffened along the edges. 610 Casings supporting one or more decks above shall be ad-equately strengthened.

Guidance note:Notes to Table B1:

1) For frame spacings differing from those indicated in the ta-ble, the table values for web thickness and flange area arecorrected in proportion to the frame spacings.

2) In vessels with rise of floor amidships greater than half therule height of the floor, the flange area may be reduced by40 H/d%.H/d = rise of floor amidships/draught to lower side of bot-tom laminate at centre.

3) When the span ls of centre girder is greater than the breadthB of the vessel, the table values for flange area and webthickness of floors are multiplied by a factor f1 taken fromthe following table.

4) Web thickness ts is measured as shown in the sketch.


Centre girder

Guidance note:For girder spans greater than vessel’s breadth, the table values forflange area and web thickness of the girder are multiplied by thefactor f1 given in note 3 to Table B2.Side Girders

For side girders:

Flange area = f2 x flange area of centre girderWeb thickness= 0.9 x web thickness of centre girder.


C. Single skin constructions

C 100 General101 In this section the general requirements for the localstrength of stiffened single skin constructions are given.102 Buckling strength of single skin panels subjected to lon-gitudinal hull girder or local compression loads will be individ-ually considered.

C 200 Laminate thicknesses201 The thickness of structural laminates, excluding topcoatand gelcoat, shall not be less than the largest value found fromthe following formulas:

t0 and k are taken from the table below.fp is taken from the formulae in 202.

kp = 3.82 for bottom panels = 4.73 for side panels = 4.11 for panels elsewhere and for all stiffening mem-

bers.

Table B2 Floors in single bottomHeight of floor at vessel’s centreline x webthickness

(mm x mm). Flange area (cm2)Bd 2 3 4 5 6

0.5 120 x 61.5

150 x 62

1.0 120 x 72

170 x 72

230 x 74

1.5 140 x 83

190 x 83.5

250 x 85

295 x 8.79

2.0 210 x 9.74

270 x 9.56

320 x 10.510

345 x 12.314

2.5 230 x 115

290 x 117.5

340 x 1211.0

375 x 13.515

3.0 310 x 129

360 x 13.512

400 x 1516

3.5 385 x 14.813

425 x 16.517.5

Basic frame spacing s in mm350 350 350 360 380

B = breadth of vessel in metresd = draught in metres to lower side of bottom laminate (meas-

ured at centreline).

ls/B 1.10 1.25 1.50 2.00f1 1.13 1.25 1.37 1.50

Table B3 Longitudinal bottom girdersFlange area in cm2/web thickness in mmBd 2.5 3 4 5 60.51.01.52.02.53.03.5

3.0/6.03.5/6.05.0/8.0

3.0/5.03.6/8.3

5.0/11.06.1/13.37.0/15.2

8.0/10.011.9/12.214.0/15.015.5/17.518.4/19.6

18.0/13.023.0/15.227.0/18.031.0/20.435.0/22.3

35.0/16.341.0/18.746.0/21.051.0/23.0

B = breadth of vessel in metresd = draught in metres to lower side of bottom laminate.

Vessel’s breadth B in metres4 5 6

f2 0.40 0.47 0.50

t min t0 kL+( ) fb (mm)=

tp kpfps P (mm)=

DET NORSKE VERITAS


kv = 0.86 + 0.014 · V H = deck cargo in ton/m2.

202 The combined correction factor, fp, is given by:fp = fp1 · fp2 · The aspect ratio correction, fp1, is to be taken from the diagrambelow:

a and s are the longest and shortest panel edge respectively.The panel curvature correction, fp2, is to be taken as:

fp2 = 1 - h/sfp2 min = 0.8.

203 Reduced thicknesses may be accepted provided equiva-lent impact resistance can be documented.

C 300 Local laminate reinforcement301 The structural laminates shall locally be reinforced to a

thickness not less than:tl min = (t0 + k · L) · (mm)t0 and k are given in the following table:

Extension of keel laminate is shown below.

Keel type 1

Keel type 2

Keel type 3

D. Sandwich constructionsD 100 General101 In this section the general requirements for the localstrength of sandwich constructions are given.102 Buckling strength of sandwich constructions subjected

Table C1 Laminate thickness

ItemL ≤ 15 m L > 15 m

t0 k t0 kHull bottom 2.5 0.58 · kv 8.6 0.17Hull side 2.0 0.58 8.1 0.17Transom, not sup-porting engine 2.0 0.58 8.1 0.17

Exposed deck 1.7 0.42 6.8 0.08Cargo deck 1.7 + H 0.42 7.3 0.08Accommodation deck 1.7 0.42 6.8 0.08

Superstructures and deckhouses 1.7 0.42 6.8 0.08

Structural/water-tight bulkheads 1.1 0.42 6.2 0.08

fb

0.75

0.80

0.85

0.90

0.95

1.00

1 1.2 1.4 1.6 1.8 2 2.2

a/s

fp1

Table C2 Laminate reinforcementItem L ≤ 5 m L > 15 m

t0 k t0 kKeel type 1 and 2 2.9 0.9 · kv 14.5 0.14Keel type 3 3.5 1.1 · kv 17.5 0.17Fore and aft stem 2.9 0.9 14.5 0.14Chine and transom corners *) 2.4 0.7 · kv 12.0 0.11Bottom laminate in way of rudder stock, shaft brackets, etc.

3.5 1.1 · kv 17.5 0.17

*) Breadth to each side shall be min. 25 B (mm), but not less than 100 mm

fb

DET NORSKE VERITAS


to longitudinal hull girder or local compression loads will beindividually considered.

D 200 Panel requirements201 The thickness of skin laminates of sandwich panels shallnot be less than:

ts min = (mm)

tl min= minimum thickness found from C201fc = 0.94 + 0.12 · σc σc = compressive strength of the core material in N/mm2.

k is found from the table below:

202 The section modulus and moment of inertia of a 1 cmwide panel strip shall be not less than:

W = 0.04 · fw · P · s2 (cm3)

fw = fw1 · fnI = 0.0364 · fi · p · s3 (cm4)fi = fi1 · fi2 · fi3The correction factors for panel aspect ratio, fw1 and fi1, arefound from the diagram below:

Figure 2 Correction factor

a and s: longest and shortest panel side, respectively.The correction factor for laminate strength, fn, is given inA301.The correction factor for laminate stiffness, fi2, is to be takenas:

fi2 =

The stiffness factor, fi3, is to be taken as:

fi3 = 1.0 for decks and floor panels = 0.5 elsewhere.If the stiffness of the panel is increased due to curvature, a low-er moment of inertia may be accepted.W and I properties for panels with skin laminates of equalthicknesses are given in 205.203 The shear strength of the core material shall be not lessthan:

τu = (MPa)

For core materials in bottom panels of planning craft documen-tation of dynamic properties of the material may be required.The shear strength of bottom panels is not to be less than:0.04 V (MPa), minimum 0.7 MPa.The shear strength of other panels is not to be less than:0.4 MPa.The thickness of the core is not to be less than: 10 · s (mm).d= panel thickness in (mm) measured as the distance betweenthe centreline of the laminates, as shown in 205.The correction factor for panel aspect ratio, fT1, is found fromthe diagram below.

Table D1 Panel requirements

Structural memberk

Exposed 1) Protected 2)

Hull bottom 0.4 0.3Hull side and transom*) 0.42 0.31

Cargo deck 0.63 0.48

Exposed deck 0.63 0.48

Accommodation deck 0.4 0.3

Superstructures and deckhouses 0.4 0.3

Structural/watertight bulkheads 0.4 0.31) The term exposed means a side of a panel which is subject to

permanent liquid submergence or which can be exposed to local mechanical abrasive or impact loads.

2) The term protected means a side of a pane which is not subject to loads as described above.

*) Transom not thrust bearing

kt1minfc

----------------

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3

a/s

fi1

fw1

7000En

------------

1.5fT1Psd

----------------------

DET NORSKE VERITAS


a and s: longest and shortest panel side, respectively.204 Reduced thicknesses may be accepted provided equiva-lent impact resistance can be documented.205 Section modulus (W) and moment of inertia (I) of a 1 cmwide sandwich panel with skin laminate of equal thickness, aregiven in the figures below as a function of core thickness K andskin laminate thickness t.

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3

a/s

fT1

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2 3 4 5 6 7

t [mm]

W /

cm

[cm

3 ]

40 30

5

10

15

20

25

35

K[mm]

0.00

0.10

0.20

0.30

0.40

0.50

2 2.5 3 3.5 4 4.5 5t [mm]

W /

cm

[cm

3 ] 5

1015

K[mm]

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

2 3 4 5 6 7t [mm]

I / c

m

[cm

4 ]

40 30

5

10

15

20

25

35

K[mm]

0.00

0.10

0.20

0.30

0.40

0.50

2 2.5 3 3.5 4 4.5 5

t [mm]

I / c

m

[cm

4 ]

5

1015

K[mm]

DET NORSKE VERITAS


D 300 Local panel reinforcements301 The sandwich panel skin laminates shall locally be rein-forced to a thickness not less than:

ts min = (mm)

tl min = minimum thickness according to 330fc = 0.94 + 0.12 · σc .where σc is compressive strength of the core material in MPa.k is found from the table below:

E. Frames, girder and stiffenersE 100 General101 In this section the general requirements for the strengthof laterally loaded frames, beams and other stiffeners in singleskin and sandwich constructions are given.102 Stiffening profiles are normally to be attached to thebase panel by secondary bonding.103 Where continuous stiffening profiles of the same heightand built with a weak core material, are crossing each otherload bearing core inserts may be required to provide sufficientshear strength.

E 200 Section modulus201 The section modulus of stiffening members is not to beless than:

W = 4.0 · m· fn · P · b · l2 (cm3)I = 36.4 · d · fi · P · b · l3 (cm4)

b = load breadth in metresl = stiffener span in metres, for curved frames see 202.m- and d- values for the most common structural members arefound from the table in 203.fn and fi are given in 204.202 For curved frames the length l which determines thescantlings is given by:l = l0 – 3 · f + 0.3 · R metresl0 = length in metres of the straight part of the frame in bottom.When the bilge radius is constant, l0 is measured as shown inFig.2 below. When the radius varies, l0 is measured as shownin Fig.3 below.R = bilge radius in metres.

Figure 3

Figure 4

For S-shaped frames the length which determines scantlings ismeasured as shown in Fig.4 and Fig.5.

Figure 5

Figure 6

Table D2 Local panel reinforcement

Itemk

Exposed 1) Protected 1)

Keel type 1 and 2 0.4 0.3Keel type 3 0.6 0.3Fore and aft stem 0.4 0.3Chine and transom corners *) 0.4 0.3Bottom laminate in way of rudder stock, shaft brackets, etc. 0.4 0.3

1) The term exposed means a side of a panel which is subject to permanent liquid submergence or which can be exposed to lo-cal mechanical abrasive or impact loads.

2) The term protected means a side of a panel that is not subject to loads as described above.

*) Breadth to each side shall be min. 25 B (mm), but not less than 100 mm.

kt1minfc

----------------

DET NORSKE VERITAS


203 The m- and d-values are normally to be taken as followsfor the various structural members:

204 The correction factors for laminate properties are to betaken as follows:

If the various parts of the stiffener, including the plate flange,have different strength and stiffness “equivalent sectional are-as” shall be used when calculating the section modulus of thestiffener.The “equivalent sectional area” is found by multiplying the ac-tual area with the stiffness ratio Ea/Er. A condition for employ-ing this method is that the strength ratio σa/σr is not less thanthe stiffness ratio above.

Ea, σa = tensile modulus and strength respectively of thelaminate considered

Er, σr = tensile modulus and strength respectively of the ref-erence laminate for which the section modulus re-quirement is calculated.

205 Section modulus W for profiles with panel as function offlange area Afl core height H and web thickness ts is given inthe graphs.

Figure 7 Definition of Afl, H and ts

Figure 8 Section modulus W of profiles

206 Section modulus W of skin laminate steps as function ofstep height and laminate thickness t.

Table E1 Section modulus parameters

Item m d

Continuous longitudinals 0.85 0.4

Non-continuous longitudinals 1.00 1.0

Transverse 1.00 1.0

Vertical members, ends fixed 1.00 1.0

Vertical members, simply supported 1.35 2.0

Bottom longitudinal 0.85 0.4

Bottom transverse 1.00 1.0

Side longitudinal 0.85 0.4

Side vertical 1.00 1.0

Deck longitudinal 0.85 0.4

Deck transverse 1.00 1.0

W.T. bulkhead, fixed ends 0.65

W.T. bulkhead, fixed one end 0.85

W.T. bulkhead, simply supported ends 1.25

Tank and cargo bulkheads, fixed ends 1.00 1.0

Tanks and cargo bulkheads, simply sup-ported ends 1.35 2.0

Deckhouse stiffener 1.00 1.0

Casings 1.00 1.0

fn80

σnu---------=

fi7000Ea

------------=

100

200

300

400

500

600

700

800

900

1000

0 5 10 15 20 25 30Afl (cm2)

W(cm3)

ts (cm)

30 28 2624

22

20

18

16

14

12

10.85 2.2521.751.51.25

H(cm)

DET NORSKE VERITAS


0

5

10

15

20

25

30

35

40

0 5 10 15 20 25t [mm]

W (c

m3 )

6 5

4

3.5

3

2.5

2

1.5

1

H(cm)

4.5

DET NORSKE VERITAS


SECTION 5 THERMOPLASTIC STRUCTURAL DESIGN

A. GeneralA 100 Premises101 Premises for manufacturing of boats of thermoplasticsshall be suitable for the production process applied. 102 Uncontrollable draughts must be avoided in the vicinityof the production machinery and in cooling rooms. 103 Premises and production machinery shall be arranged toavoid risk of pollution by oil spill, dust etc.

A 200 Marking of produced boats201 If the applied structural material has properties of signif-icance for the use of the boat which differ from the standardgiven for boats of glassfibre-reinforced polyester, appropriateinformation will be given on the certificate.202 The boat is to have a durably fitted plate or similar whichclearly states the structural material of the boat.203 The boat manufacturer shall supply the following witheach boat: information on the boat's presupposed use, direc-tions for maintenance and repair as well as information on sub-stances which may have detrimental effects on the boat'sstructural material.

B. Rotation moulding of polyethylene boatsB 100 Moulding condition101 Release compositions applied to the mould are not tohave any detrimental effects on the boat material, e.g. stresscracking.102 Regenerated raw material will not be accepted for use inhulls manufactured by rotation moulding.103 The rotation procedure shall be the same for moulding ofall boats of the same type. 104 The weight quantity of powder in the mould is not to beless than 1% below the specified value.105 The temperature shall be automatically controlled. Thetemperature and its specified permissible variations will besubject to approval in each case, on the basis of the limitationsof the raw material properties. The temperature at each meas-uring point is not to vary by more than +5°C for each mouldingprocess.106 The sintering time and the after-sintering time is stipu-lated on the basis of thickness measurements on the boat typein question to ensure that an even distribution of material in themould is obtained. The process time is not to vary by more than+ I minute from the approved time. Any welding together ofinner and outer mould is to be approved in each separate case.107 The cooling-down process is to be the same for eachboat of the same type, and will be stipulated on the basis of thesintering temperature, boat type and raw material, so that de-formations in the material are avoided.108 If alterations are made in the manufacturing method, theSociety is to be informed for considering whether special testswill be required to check the material quality.

B 200 Moulded boats201 The material in the finished moulded boats is to be with-out any visible surface flaws of significance to the boat's serv-ice. Surfaces and cross sections are not to show any sign of

either insufficient fusion of the powder particles or thermaldegradation of the material.202 Pores or air bubbles must not be so numerous or of suchsize that the material properties are significantly reduced. Theamount and size allowed shall be stipulated for each type ofmaterial.203 The material in the moulded boats is to comply with therequirements to minimum mechanical properties specified forthe raw material in question.204 Completed boats must not have significant deforma-tions, and all welded joints are to be tight.

B 300 Internal control301 The boat manufacturer shall keep a journal of the rawmaterial supplier's certificate data, and store samples fromeach material delivery. 302 The boat manufacturer is to record the following processdata for each individual boat:

— weighed quantity of powder— temperature— sintering and after-sintering time— cooling-down time.

303 Each boat shall also to be visually checked for surfaceflaws and tightness of welded joints.304 Each boat shall be marked with its production number,which also shall identify the mould in which the boat has beenmanufactured. The marking is to be made in a durable way. 305 Thickness measurements shall normally be carried outon boats that are cut into several sections. Such measurementsshall be carried out on one out of 200 boats manufactured ineach mould.

C. Thermoforming of ABS-sheetsC 100 Forming of sheets101 The forming process shall be such that the material prop-erties are not significantly reduced during the production proc-ess. After checking the thickness of some completely formedboats, the thickness of the sheets to be used in production of theboat type shall be decided. 102 The temperature distribution on the sheet shall be thesame for all boats formed. The temperature of the sheet and themould must be within the limits specified for the relevant ma-terial. 103 After forming of the hull the yield point of the materialunder tensile testing is not to deviate by more than 20% fromthe yield stress in the production direction. The mean valuefrom 5 test specimens shall be used as a basis. 104 Stressed structural parts shall be formed without sharpedges. The radius of any curvature on the mould side shall notbe less than twice the rule thickness, and on the opposite sidenot less than 5 times the rules thickness. Sharper edges may,however, be accepted if special reinforcements reduce thestress concentration.

C 200 Internal control of the boat manufacturing201 The boat manufacturer shall keep a journal of the sheetsupplier's certificate data. 202 Each thermoformed sheet shall be visually checked for

DET NORSKE VERITAS


surface flaws. 203 At positions agreed with the Surveyor, the skin thicknesson the boats in production should be checked by measurementat least once a day, and at least once for every 50 boats. Theresults shall be recorded.

D. Boat constructionD 100 Design101 The design of the boat shall be suitable for the manufac-turing process and the raw material being used. 102 When forming boats of thermoplastics, it is to be takeninto consideration that the mechanical properties of the mate-rial vary with the temperature and the duration of the loading.103 Hard points in the structure are as far as practicable to beavoided. Stiffening is to be evenly distributed over the hull, tothe extent this is practicable.104 The design is to be such that sufficient hull stiffness isobtained. Large flat surfaces are to be avoided as far as practi-cable.

D 200 Assembly201 No materials built into the boat must have detrimentaleffects on the other materials applied.202 The skins in double hulled constructions and in sand-wich constructions shall be watertight. Screws or bushings inthe skins must also be watertight. 203 Where exposed, the connection between inner and outerskin shall be watertight.

D 300 Rule thickness301 Rule thickness is the value stated in subsections E and F. 302 A measured thickness is regarded as satisfactory whenthe average of the values measured at 20 points is not less thanthe rule thickness and if none of the values measured at the in-dividual points is more than 15% below rule thickness.303 Local reinforcements that are welded or glued to thehull, may upon special consideration be regarded as part of theskin thickness.

E. PolyethyleneE 100 Manufacturing101 Requirements to moulding time, temperatures and cool-ing time are determined based on quantity of powder used andthe rotation speed, on the background of inspection of com-plete moulded boats.102 Raw materials should be approved in accordance withCh.3 Sec.4.103 If the boat manufacturer is to grind granulate to powder,the grinding and sieving equipment are first to be approved bythe Society.104 A pigment of approved type and in the approved quanti-ty is to be added to the powder. During or after the grinding thepowder is to be sifted through a mesh of not more than 800 m.105 Material moulded in accordance with the boat manufac-turer’s actual procedure shall at least have properties as givenin the tables in Ch.3 Sec.4 C100 to C300.

E 200 Scantlings, LDPE and MDPE201 The thickness of the outer hull bottom and side shall notbe less than:

where

k = 1.0 for LDPEk = 0.85 for MDPEs = stiffener spacing in meterPF = pressure factor for bottom, respectively side (PFb and

PFs), taken from the figures in Ch.4 Sec.2 B200 toB300.

202 The thickness of the inner hull is not to be less than:ti = 0.8 ty mm

203 Rotation moulded boats should have a hull weight of atleast k x 45 kg. The boat should be stiffened in such a way thatkeel, bottom or side sheets are not to be deformed or deplacedby normal load without reducing the usage of the boat.204 Transom for engine mounting is normally to be stiffenedover its full breadth. Scantlings based on practical testing withsimulated loads from the engine may be accepted.

E 300 Surveillance of the production301 Moulding time, temperature, density and meltindex ofthe materials shall be recorded.302 The inner surfaces and weldings are to be visually in-spected and the hull thicknesses measured by cutting varioussections of the boat.

F. Acrylnitrilbutadienestyrene (ABS) and equivalent materials

F 100 Manufacturing conditions101 Requirements to forming temperature and sheet thick-ness are determined for each boat type on the basis of inspec-tion of completed boats.

F 200 Material requirements201 Raw materials shall be approved according to Pt.7 Ch.1.202 Material tests are carried out on sheets produced withlow internal stresses and low orientation. When testing theshrinkage of the sheet, the test specimens are to be heated to150°C.203 When using foam in structural members, the followingrequirements are to be complied with:

F 300 Scantlings301 The following scantling requirements are based on aboat speed not exceeding 10 knots.302 Thickness of outer hull:The bottom thickness is not to be less than:

tb = 1.5+ 0.4 L + 0.06 V mmtb min = 2.6 mm.303 The side thickness is not to be less than:

ts = 1.5+ 0.4 L mmts min = 2.4 mm.304 The thickness of the inner hull is not be less than:

Table F1 Foam propertiesProperties Requirements FoamCompressive strength 0.4 N/mm2

Shear strength 0.4 N/mm2

Connection skin/core Fracture in glued joints is not to occur

ty ks PFL 6.7-------------- 14 3.6 L+( ) mm=

DET NORSKE VERITAS


ti = 0.9 ts mmti min = 2.2 mm.305 If the boat is intended for a speed exceeding 10 knots,the material thickness will be considered in relation to the stiff-ening system and the boat speed in each case.306 Boats built in accordance with the above requirementsshall have at least one longitudinal stiffening or the equivalent.The need for any additional stiffening will be considered ineach case.307 The transom is normally to be stiffened over its fullbreadth if use of outboard engine is intended. Scantlings based

on practical tests with simulated loads from the engine, may beaccepted.308 All stiffening shall be of such shape that stress concen-trations are avoided as far as practicable.

F 400 Surveillance of the production401 The yield stress of the material before and after formingis checked by random sample testing.402 By random sample testing at the raw material manufac-turer the sheet thickness, shrinkage, and impact strength testedwith drop weight shall be checked.

DET NORSKE VERITAS




CHAPTER 5

MACHINERY AND SYSTEMS

CONTENTS PAGE

Sec. 1 Machinery................................................................................................................................. 67Sec. 2 Driven units .............................................................................................................................. 68Sec. 3 Steering .................................................................................................................................... 69Sec. 4 Piping Systems and Tanks ....................................................................................................... 71Sec. 5 Electrical Systems ................................................................................................................... 73Sec. 6 Fire Safety ................................................................................................................................ 75Sec. 7 Navigation ............................................................................................................................... 77Sec. 8 Other systems .......................................................................................................................... 78

DET NORSKE VERITAS


SECTION 1 MACHINERY

A. CertificationA 100 Engines101 Engines shall be of recognised type adapted for mari-time use. Engines with a power exceeding 2 500 kW shall beType Approved by DNV or another recognised organisation.Individual product certificates are not required.

B. Propulsion and auxiliary engines B 100 Engines101 Inboard diesel engine(s) shall normally be used for mainpropulsion. Outboard petrol engines may be accepted when Lx B is smaller than 40. Requirements to outboard petrol engineinstallations are given in Ch.6.

B 200 Engine room201 The engine room shall not be used for other purposes.The normal service points of the engine shall be readily acces-sible. Rotating parts shall be shielded to prevent personal inju-ry.202 Windows, scuttles or similar in engine room shall havethe same fire rating as surrounding structure. 203 The engine room shall be equipped with artificial light-ing.204 Ventilation of the engine room for the engine’s air con-sumption and cooling shall be arranged according to the enginemanufacture’s recommendations. The engine room/space shallhave ventilation to the outside. The total cross sectional area ofintake ventilation openings and ducts shall not be smaller than7 cm2/kW or the engine manufacturer’s recommendations.205 Ventilation openings shall be equipped with fire closingappliances that can be operated from outside the engine roomand secured in open and closed position.

B 300 Engine controls301 Engines shall be possible to monitor from the helm po-sition. The following indicators or alarms shall be visible/audi-

ble:

— speed of revolutions (may be omitted for auxiliary en-gines)

— lubrication oil pressure— cooling water temperature— alarm for loss of exhaust cooling.

The instrumentation shall be equipped with adjustable light-ing. 302 Boats with an open steering positions and a maximumspeed exceeding 25 knots shall have a safety contact at thesteering position which will stop the propulsion engine if thehelmsman should fall overboard.

B 400 Exhaust401 Each engine shall have a separate exhaust system or ac-cording to the engine manufacturer’s recommendations.402 Exhaust lines shall be accessible for inspection. 403 Exhaust line with a surface temperature exceeding 80°Cshall be equipped with protection against touching. Exhaustpiping shall not be arranged in such a way that other materialsor structures reach temperatures above 65°C.404 Materials in seawater cooled exhaust systems shall becorrosion resistant. Special attention shall be given to avoidgalvanic corrosion.405 Seawater cooled exhaust systems shall be equipped withalarm at the steering position for loss of seawater cooling or forhigh temperature in the exhaust pipe.406 Exhaust outlets shall be at least 100 mm above loadedwater line or the exhaust line shall consist of a metallic pipebrought at least 100 mm above loaded water line.407 At one location the lower inside surface of the exhaustpipe shall be at least 350 mm above loaded water line. Fromthis location the pipe shall fall continuously to the exhaust out-let.408 Flexible rubber and plastic hoses for wet-exhaust systemshall be a class B hose according to ISO 13363:2004.

DET NORSKE VERITAS


SECTION 2 DRIVEN UNITS

A. Shafting A 100101 The diameter of steel shafting shall be in accordancewith the engine manufacturer’s recommendation, but notsmaller than:

P = maximum continuous power of driving engine(kW)

RPM = shaft revolutions pr. minuteRm = tensile strength (MPa).102 The dimensions of shafting fabricated from other mate-rials are subject to special consideration.

B. Shaft brackets and stern tubesB 100101 Shaft bearings shall be sufficiently lubricated.102 One-armed shaft brackets shall have a section modulusW at the craft’s bottom not smaller than:

d = shaft diameter (mm)l = length of bearing (mm)Rm = tensile strength (MPa).At the bearing the section modulus shall not be smaller than0.6 W.

C. Gears, propellers and waterjets Gears, propellers and water-jets shall be supplied by recog-nised manufacturers. The equipment shall be approved byDNV, either by a Type Approval or on a case by case basis.

)(160

600903/13/1

mmRRPM

Pdm

⎟⎟⎠

⎞⎜⎜⎝

⎛+

⋅⎟⎠⎞

⎜⎝⎛⋅= )(

1123

2cm

RdlW

m⋅⋅

=

DET NORSKE VERITAS


SECTION 3 STEERING

A. Definitions A 100101 The following definitions apply in this section:

K = steering force on tiller at point of actuation (N)F = steering force on rudder (N)A = rudder area (m2)V = maximum craft speed (knots)Sa = length of tiller from rudder stock centre to point of ac-

tuation (mm)Sb = distance from pressure centre of rudder to lower rudder

bearing for spade rudders, to upper bearing for balancerudder (mm)

Sv = distance from rudder pressure centre to axis of rotation,not to be taken smaller than 40% of the chord length aftof the leading edge for plate rudders, not to be takensmaller than 30% of the chord length aft of the leadingedge for profile rudders (mm)

P = maximum engine power output (kW)M = combined bending moment and torque on rudder stock

(Nmm)d = diameter of rudder stock (for solid stock) (mm)σ0.2= yield stress of rudder stock or other item, as applicable

(MPa).

B. Arrangements B 100 General101 The steering arrangement shall ensure reliable manoeu-vring of the craft at the maximum engine power for which thecraft is certified. The steering system shall be protected. 102 It shall be possible to steer the craft by means of anemergency arrangement also when the normal means of actu-ating the rudder/waterjet has failed.103 Rudder stops shall be fitted.

C. Forces on steering systemC 100 Rudder steering101 The steering force K with rudder shall not be takensmaller than:

with F not taken smaller than:

The means of actuating the rudder shall have a capacity corre-sponding to not less than 2 times the maximum torque on therudder stock.

C 200 Waterjet installations201 The steering forces from water jets shall be specified bythe manufacturer of the water jet.

D. Rudder stock

D 100 General101 The combined bending moment and torque, M, on therudder stock shall not be taken smaller than:for balance rudders

for spade rudders

102 The diameter d of the rudder stock shall not be smallerthan:

for solid stocks.Hollow stocks shall satisfy the following criteria:

do = outer diameter of stockdi = inner diameter of stock.103 The length of the bearings shall normally not be smallerthan d. The nominal contact pressure on the bearing (stock di-ameter x length of bearing) shall normally not exceed:

7.0 (MPa) for steel against steel4.5 (MPa) for steel against white metal5.5 (MPa) for steel against synthetic materials,

water lubricated.104 The diameter of pintles shall not be smaller than 0.6 · d + 5 mm. 105 Fillets shall be carried out with radii such that unduestress concentrations are avoided.106 The diameter of bolts, db, in flanged couplings shall notbe smaller than:

n = number of bolts, shall not be smaller than 4PCD = pitch circle diameter, shall not be smaller than 2 · d.The thickness of the flanges and there width outside the boltholes shall not be smaller than db.107 The packing box of the rudder stock housing shall nor-mally not be placed lower than 100 mm above the deepest wa-terline. If placed below a grease filled packing box with at leasttwo seals shall be fitted.

(N)

a

v

SS

FK ⋅=

)(110 2 NVAF ⋅⋅=

( ) )(224

2/12 NmmSSFSFM vb

b⎟⎟⎠

⎞⎜⎜⎝

⎛⋅+⋅+

⋅=

( ) )(222

2/12 NmmSSFSFM vb

b⎟⎟⎠

⎞⎜⎜⎝

⎛⋅+⋅+

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65.0 mmn

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DET NORSKE VERITAS


E. RudderE 100101 Rudders can be fabricated from steel, aluminium or fibrereinforced thermosets (FRP). FRP can be used in profile rud-ders only.102 The plate thickness t in plate rudders shall not be smallerthan:

t = 3 + 0.125 d (mm)103 The plate thickness of profile rudders shall not be small-er than:

t = 4 (mm)104 In addition to the requirements to minimum thicknessthe following requirements shall be 105 The section modulus W of the rudder at any horizontalsection through the rudder shall not be smaller than given by:

Mbend = bending moment at the cross section due to maxi-mum rudder lift force

σall = allowable bending stress.σall shall not be taken larger than:- 50% of specified minimum yield strength for steel.- 50% of minimum yield strength in welded condition for alu-

minium.- 33% of ultimate tensile/compressive strength as relevant for

FRP.106 The total effective shear area Aweb of vertical webs inany horizontal cross section shall not be smaller than given by:

S = maximum lift force of the part of the rudder below thecross section

τall = allowable shear stress.τall shall not be taken larger than:- 29% of specified minimum yield strength for steel.

- 29% of minimum yield strength in welded condition for alu-minium.

- 33% of ultimate shear strength for FRP.

F. Steering systemF 100 Hydraulic steering system with or without exter-nal source of power101 The capacity of the steering system shall be document-ed. 102 The complete installation shall be tested for leaks.103 The satisfactory function of the steering system shall beverified by practical operational test at sea trial.104 Hand operated hydraulic steering systems shall be CE-marked according to Council Directive 94/25/EC and installedaccording to the manufacturers recommendations.

F 200 Cable steering system201 The capacity of the steering system shall be document-ed. 202 Cable steering systems shall be CE-marked according toCouncil Directive 94/25/EC and installed according to themanufacturers recommendations.203 The satisfactory function of the steering system shall beverified by practical operational test at sea trial.

F 300 Steering wheel301 Steering wheels shall be CE-marked according to Coun-cil Directive 94/25/EC. For not CE-marked steering wheels therequirements below apply.302 For small high speed craft the steering wheel shall betested with force equal to 700 N in the forward and aft ward di-rection applied at the weakest point of the steering wheel pe-riphery. The test shall be carried out at room temperature. Thesteering wheel shall exhibit no breakage or permanent defor-mation after the test.303 For open steering positions a steering wheel fabricatedfrom plastic materials without structural metal frame shall notshow any major decrease in strength after ageing in xenon lightcorresponding to 4 years of natural ageing. This requirementmay be deleted for black wheels.

all

bendMW

σ=

allweb

SAτ

=

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SECTION 4 PIPING SYSTEMS AND TANKS

A. General

A 100 General101 The material(s) used in piping systems shall be suitablefor the carried liquid and external environment to which it isexposed. Corrosion and variation in temperature shall be con-sidered. Different materials shall not be combined such thatthere is a possibility for galvanic corrosion. 102 All components in the installation shall have sufficientstrength and be so mounted that the system including its foun-dations will withstand the accelerations and vibrations towhich it may be exposed as well as the design pressure. Theyshall be protected against mechanical damage. Expansionloops or equivalent arrangement shall be provided to allow ex-pansion/contraction of pipes.103 Flexible hoses used in fuel system, seawater cooling sys-tem, bilge system and other systems where a failure of the con-nection will lead to flooding shall be fitted with two stainlesssteel hose clips or pressed on end couplings. 104 Pipes or hoses shall not be installed over switchboard orelectrical distribution panels.

B. Bilge System

B 100 Arrangement101 The bilge system shall normally consist of rigid pipesfabricated from steel, FRP or thermoplastics. Metallic materi-als shall be used in the engine room. The bilge system shall bepermanently installed. If flexible hoses are used attention shallbe given collapse due to suction.102 The bilge system shall be able to empty all compart-ments except tanks.103 Separate suction lines shall be fitted to each watertightcompartment and be equipped with a valve between the mainbilge line and the individual suction line. The valve shall bepossible to operate from above floors. Emptying by use of thebilge system of small compartments may not be required basedon special consideration.104 One bilge pump driven directly by the engine or by elec-tric motor shall be installed. The bilge pump shall have a ca-pacity Q not smaller than:

The bilge pump shall be possible to operate from the steeringposition. For craft with L larger than 6 m minimum two pumpsshall be fitted, each with at least 50% of the capacity givenabove.105 Alternative to the arrangement using one bilge pump,separate bilge pumps may be installed for one or more com-partments. Pumps shall be possible to operate from the steeringposition.

B 200 Alarm201 Engine and cargo spaces shall be fitted with bilge alarm.This does not apply to open craft.

C. Fuel systemC 100 Arrangement101 Fuel strainers, filters and water separators shall be easilyaccessible and possible to replace, drain and clean with enginein operation. 102 Fuel tanks shall not be located above the engine. 103 Fuel tanks may be integral or separate. Separate tanksshall be mounted such that air can circulate freely around thetank and such that they can be readily inspected or movable forinspection.

C 200 Fuel tanks201 Fuel tanks shall be fabricated from steel, aluminium,polyethylene or FRP. Tanks in engine room shall be fabricatedfrom steel or aluminium.202 The design pressure p of fuel tanks shall be taken as thelarger of:

p = 25 · hs (kN/m2), andp = 6.6 · hp (kN/m2), andp = 25 (kN/m2)

hs = height of tank (m)hp = height from bottom of tank to top of filling and

air pipe (m).203 The plate thicknesses (mm) shall not be smaller than:

204 Fuel tanks shall have an inspection hatch. For removabletanks an inspection hatch is not required.205 Wash bulkheads shall allow adequate circulation of thefuel along the top and bottom of the tank.206 Each tank shall have separate filling pipe and air vent.The air vent shall be mounted in a way to prevent water fromentering the tank. The filling pipe shall have an internal diam-eter of at least 38 mm. The vent pipe shall have an internal di-ameter of at least 16 mm. If the filling pipe has a screwcoupling or similar device for the filling line, the internal crosssectional area of the vent pipe shall not be smaller than 125%of the internal cross sectional area of the filling pipe.207 The amount of fuel in the tank arrangement shall be pos-sible to verify at any given time, e.g by fitting a level gauge toeach tank. External sight glass shall have a self-closing valves.

C 300 Fuel piping301 Fuel lines may consist of metal pipes or flexible hoses,or a combination thereof. Fuel lines shall not pass over en-gine(s) or be arranged such that a leakage can occur on tosources of ignition (e.g. hot surfaces).

Table B1 Bilge pump capacityLoa (m) Capacity (l/minute)

< 8 60 8 – 10 8010 – 12 12012 – 15 18015 – 24 250

Carbon steel: 2.0 (mm)Stainless steel: 2.0 (mm)Aluminium: 2.0 (mm)FRP: 4.0 (mm)PE: 5.0 (mm).

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302 The engine shall be connected to the fuel line by a shortflexible hose.303 Flexible hoses shall satisfy the requirements of ISO7840 Small craft fire resistant fuel hoses type A1 or A2, and bemarked in accordance with this standard. 304 Fuel lines shall be equipped with a metallic shut-offvalve mounted on the tank. The valve shall be possible to closefrom above deck.305 At least two hose clips fabricated from stainless steelshall be used at each connection on flexible hoses. Spigotsshall be sufficiently long to accept the hose clips and havegrooves or a bead.306 Flexible hoses for pressurised system(s) shall be fittedwith pressed on end fittings.

C 400 Testing401 After installation a leakage test shall be carried out of thewhole installation with a pressure equal to 20 kPa.

D. Seawater cooling systemsD 100 General101 Flexible hoses may be fitted. Flexible hoses shall bemounted in such a way that they are protected against mechan-ical damage. Flexible hoses shall comply with the same re-quirements given for flexible hoses used in fuel systems.Flexible hoses shall be secured with at least two stainless steelhose clips or pressed-on couplings.102 Seawater intakes shall have strainers or filters. All filtersshall be fitted such that they can be cleaned while the engine isrunning.

E. Freshwater systems and grey water systems

E 100 General101 Fresh water tanks shall be accessible for cleaning.102 Integral freshwater tanks shall not be located contiguousto fuel or grey water tanks.103 Toilet water shall be collected in dedicated tanks possi-ble to empty from above deck.

F. Shell penetrations

F 100 General101 Penetration located lower than 200 mm above deepestwaterline shall be arranged with closing valve or other equiva-lent means for preventing water from passing inboard. Thevalve shall be readily accessible for operation from a positionabove floor, or immediately below via easy operable andmarked hatch in floor plate.102 Penetration located less than 200 mm above deepest wa-terline and connected to a system with open inboard end locat-ed below lowest part of bulkhead-deck, and penetrationlocated in a position immersed at an angle of heel of 10º, shallin addition to closing valve be arranged with non-return valve. 103 Valve shall have system name and indicator showingclosed and open position. 104 Material of valve and hull flange shall be of steel, bronzeor other equivalent accepted ductile material resistant to corro-sion.

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SECTION 5 ELECTRICAL SYSTEMS

A. ScopeA 100 General101 The present section does not apply to electrical compo-nents on the propulsion or auxiliary engine(s). Equipment con-sidered to represent a safety hazard may be required replacedor modified regardless of where it is mounted.102 The present section does not cover personnel protectionwith respect to exposure to electromagnetic fields, e.g. fromradar and CRT screens.

B. DC systems – Voltage ≤ 50 VB 100 General 101 Direct current systems which operate at nominal poten-tial not exceeding 50 V shall comply with ISO 10 133 and therequirements given in this section.102 A circuit plan shall be supplied with the craft when de-livered and be available onboard. All markings shall be perma-nent.103 Electrical fittings shall have IP rating(s) suitable for theexposure where they are located. Electrical equipment locatedin an environment with explosion hazard shall be Ex approved.Battery installations and gas installations are considered explo-sion hazard areas.

B 200 Battery installations201 Battery installations with a capacity exceeding 5 kWhshall be placed in compartments with ventilation to the outsideof the craft. Battery installations placed in accommodation ar-eas shall be ventilated separately to the outside of the craft.202 Each battery shall be marked indicating the connectedconsumers and how connections between batteries shall becarried out.203 Batteries installed inside the same watertight compart-ment as the propulsion engine(s) shall be mounted such thatthey are not short circuited when the compartment is filled withwater up to the loaded water line. Alternatively, emergencybatteries for supply to emergency lighting, navigation equip-ment and radio, may be placed above main deck.204 For main engines with electric starter, the starter shall bepossible to connect to two separate groups of batteries. One ofthe groups shall be assigned to starting and shall not be used tosupply other consumers. The other group may be one used forconsumers and which have a capacity that is sufficient to startthe main engine.

B 300 Distribution systems 301 For propulsion engines with a power output less than100 kW, the engine may be used as conductor when startingthe engine. 302 Gas alarms, theft alarms, heating equipment and auto-matic bilge pumps may be connected between the battery/gen-erator and the main switchboard, but must have separateprotection with circuit breakers. 303 Cable penetrations in watertight bulkheads and decksshall be watertight. 304 The following cables shall be carried as separate, insu-lated single conductors:

— conductor to connect generator to batteries— conductor to connect battery to electrical starter— conductor to connect battery or generator to switchboard.

The conductor between battery and electrical starter shall notbe protected by circuit breaker. The conductor shall complywith the engine manufacturer’s recommendations.305 Interior lighting shall be distributed on at least two sep-arate circuits.

B 400 Protection401 Circuit breakers shall not be placed in tank compartmentor compartments for equipment that may generate explosivegases (e.g. battery installation, gas installations).402 Safety equipment as e.g. radio, sound horn, search lightetc. and consumers with drawing a current larger than 5 A shallbe equipped with separate circuit breakers.403 Navigation lights shall have separate circuit breakers. Ifthe functioning of the navigation light can not be monitoredfrom the steering position each light shall be equipped with anoptical or audible alarm to the steering position indicating ifthe light is functioning. Malfunctioning of the system for indi-cation shall not influence the function of the navigation light.

B 500 Switchgear and controlgear assemblies501 Switchboards shall be protected against leaks and sprayfrom sea and piping and shall be accessible for maintenanceand replacement and visual inspection during operation.502 Each group on the switchboard shall be independentlyavailable for measurement of insulation.

C. AC systems – Voltage ≤ 240 VC 100 General 101 Alternating current systems which operate at nominalvoltage not exceeding 250 V shall comply with ISO 13297 andthe requirements given in this section. Such systems shall beinstalled as single phase systems.102 A circuit plan shall be supplied with the craft when de-livered and be available onboard. All markings shall be perma-nent.103 Electrical equipment located in an environment with ex-plosion hazard shall be Ex approved. Battery installations andgas installations are considered explosion hazard areas.

C 200 Distribution systems 201 Cable penetrations in watertight bulkheads and decksshall be watertight. 202 Interior lighting shall be distributed on at least two sep-arate circuits.

C 300 Protection301 Circuit breakers shall not be placed in tank compartmentor compartments for equipment that may generate explosivegases (e.g. battery installation, gas installations).302 Safety equipment as e.g. radio, sound horn, search lightetc. and consumers with drawing a current larger than 5 A shallbe equipped with separate circuit breakers.303 Navigation lights shall have separate circuit breakers. Ifthe functioning of the navigation light can not be monitored

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from the steering position each light shall be equipped with anoptical or audible alarm to the steering position indicating ifthe light is functioning. Malfunctioning of the system for indi-cation shall not influence the function of the navigation light.

C 400 Switchgear and controlgear assemblies401 Switchboards shall be protected against leaks and sprayfrom sea and piping and shall be accessible for maintenanceand replacement and visual inspection during operation.402 Each group on the switchboard shall be independentlyavailable for measurement of insulation.

C 500 Shore connections501 The cable(s) for shore connection shall have a solidsheath resistant to oil and weathering. The socket inlet shall beprotected from spray water and rain.502 Equipment connected to the shore connection shall be-come earthed to the shore connection.

D. Emergency power supply

D 100 Emergency power supply101 An alternative power supply shall be available capableof supplying the following consumers for a period of at least 3hours:

— emergency lights in wheelhouse, accommodation and en-gine room (for small craft portable flashlights may be ac-cepted as emergency lights)

— navigation lights or Not Under Command lights— fire detection and alarm systems— remote control devices for fire extinguishing systems, if

electrical— radio facilities.

The alternative power supply shall be fitted outside the engineroom and above the flooded waterline with the engine roomflooded.

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SECTION 6 FIRE SAFETY

A. GeneralA 100 Definitions101 Definitions and nomenclature in the present section fol-lows the definitions and nomenclature in the FTP Code for thecraft structure.102 The following designations are used to classify andidentify fires of different nature:

— Class A: fires involving solid material, usually of organicnature

— Class B: fires involving liquids or liquefiable solids— Class C: fires involving electrical equipment— Class D: fires involving combustible metals (i.e. magnesi-

um).

A 200 Fire safety in general201 Fire safety shall be achieved by the use of passive andactive means.202 Passive means is structural fire protection and control ofinstallations and combustible materials.203 Active means is fire-fighting equipment.204 Other requirements for fire safety than listed in this sec-tion may be specified under specific service notations.

B. Structural fire protectionB 100 Engine and tank spaces101 Engine spaces in crafts fabricated from FRP shall be en-closed with fire protection of minimum 15 minutes rating. Ar-rangement and materials for structural fire protection shall beapproved. The fire protection shall cover the entire boundaryof the engine space above lowest waterline.102 For small crafts (normally L < 15 m) other arrangementsthan specified in 101 may be accepted based on special consid-eration (e.g. intumescing paint, fire retarding resin on interiorsurface of FRP laminates).103 Fuel and lubrication oil tanks located entirely or partlyabove the floor in the engine space shall have fire resisting di-vision of at least B-15 rating. 104 Openings for ventilation of the engine space shall beequipped with closing appliances readily operable from theoutside of the engine space.105 Tank spaces separated from engine spaces need not fol-low the same requirements as given for engine spaces in 101and 102, but shall be ventilated to the outside of the craft.

B 200 Control of combustible materials201 Acoustic insulation material used in engine spaces shallas a minimum have a non-fuel-absorbent surface towards theengine and an oxygen index of at least 21 in accordance withISO 4589-3 at an ambient temperature of 60°C.

C. Portable fire extinguishersC 100 General101 The craft shall be equipped with portable fire-fightingextinguishers.

102 Any portable fire extinguisher shall be type approvedunder European Standard EN3, under the Marine EquipmentDirective or other national recognized standard.103 The extinguisher(s) fitted shall individually or as com-bined be suitable for fighting ABC-fires.104 No individual extinguisher shall be rated less than 30A/180B.105 Any individual portable carbon dioxide (CO2) extin-guisher shall have a maximum capacity of 2 kg.

C 200 Location of portable fire extinguishers201 The total number of portable fire extinguishers shall beadequate to meet the following requirements. A single extin-guisher may meet more than one of the requirements.202 Readily accessible portable fire extinguisher(s) shall belocated:

— within 2 m unobstructed distance from the main helm po-sition

— within each 20 m2 of the accommodation area— within (L/3) m from the centre of any berth, measured

horizontal— within 2 m unobstructed distance from any permanent

installed cocker/stove or open flame device.

203 Portable CO2 extinguishers shall only be fitted in ac-commodation spaces when flammable liquids are present (e.g.galley) or where energized electrical equipment is located (e.g.electric motor space, battery space, switchboard).204 Where CO2 extinguishers are used, there shall be onlyone CO2 extinguisher in each hazard area. A warning noticeshall be affixed near the extinguisher.205 If the portable fire extinguisher is located where it is ex-posed to splashed or sprayed water, the nozzle and triggeringdevice shall be shielded.206 The extinguisher may be stowed in a locker or other en-closed space. The locker or opening part of the space shall belabelled.

C 300 Fire blanket301 If an open-flame cooker is fitted, a fire blanket, in ac-cordance with EN 1869, shall be within reach and readily ac-cessible for immediate use.

D. Fire detectionD 100 Engine spaces101 The engine spaces shall be equipped with a fire detectionsystem with both audible and visible alarm at the helm posi-tion. The detection system may be part of a fixed fire extin-guishing system.

E. Fixed fire extinguishing systemsE 100 General101 Engine spaces shall be protected by a fixed fire-fightingextinguishing system.102 The system shall be a manual system or a manual/auto-matic combined system if applicable. A manual release system

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shall be activated from the helm position. The release mecha-nism shall be protected against sea-spray and unintended re-lease. The operation instruction shall be posted close to therelease mechanism.Automatic release of the system shall be indicated by both au-dible and visual alarms at the helm position.103 The extinguishing medium shall be suitable for fightingAB-fires.104 The amount of extinguishing medium and emptyingtime shall be adequate for the space considered such that thefire is efficiently extinguished.105 The fixed fire extinguishing system shall be of one of thefollowing types:

— aerosol system— CO2 system— gaseous agent— high expansion foam system— water mist systems.

106 Cylinders for the extinguishing medium shall be protectedagainst sea-spray, mechanical damage and temperatures exceed-ing 50ºC. Cylinders shall not be located in accommodation areas.107 Nozzles shall be located in a way that an even distribu-tion of the extinguishing medium is achieved.

E 200 Aerosol system201 Aerosol system shall be type approved according toIMO MSC/Circ. 1007.202 The system may be either a manual or a manual/auto-matic combined system.

E 300 CO2 system301 The system shall be manually operated only. Dischargeshall be indicated by both audible and visible alarm.302 The amount of extinguishing medium shall be minimum0.6 kg/m3 net volume, but in any case not less than 2 kg in to-tal.

303 CO2 cylinders shall not be located in the engine room.304 CO2 cylinders or fittings on distribution lines shall notbe located in a way that any extinguishing medium can enterinto the accommodation area in the event of leakage in the sys-tem.305 CO2 systems shall have a separate fire detection system.

E 400 Gaseous agent system401 Gaseous agent system shall be type approved accordingto IMO MSC/Circ. 848.402 The system may either be a manual or a manual/auto-matic combined system.

E 500 Foam system501 The system may either be a manual or a manual/auto-matic combined system.

E 600 Water mist system601 Water mist system shall be type approved according toIMO Circ. 668/728.

Guidance note:Water mist systems tested according to other standards (e.g. Fac-tory Mutual) may be accepted.


602 The system may either be a manual or a manual/auto-matic combined system.603 A water mist system shall be designed for a protectiontime of at least 20 minutes.604 Water based systems requiring fresh water shall be con-nected to dedicated water tanks with capacity for minimum 5minutes operation for the largest space, and automatic switch-over to sea-water supply. Alternatively manual switchovermay be used if the capacity of the fresh water tank is increasedto 15 minutes.

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SECTION 7 NAVIGATION

A. General A 100101 Navigation lights according to national or internationalregulations shall be fitted.

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SECTION 8 OTHER SYSTEMS

A. Cocking and heating appliancesA 100 General101 Stoves and heating units shall be securely fastened.102 Where flues are installed, they shall be insulated orshielded to avoid overheating or damage to adjacent materialor to the structure of the craft.

A 200 Units using liquid fuel201 Open-flame burners shall be fitted with a drip-pan.202 Drip-pan shall have at least 20 mm high coaming able tocollect the fuel in case of leakages.203 Where open-flame-type water heaters are installed, ade-quate ventilation and flue protection shall be provided.204 Where a pilot light is installed, the combustion chambershall be room sealed, except for cockers.205 Appliances using petrol for priming, or as a fuel, shallnot be installed.

A 300 Liquid fuel tanks301 For tanks and supply lines, the applicable requirementsof Ch.5 Sec.4 apply.302 Non-integral tanks shall be securely fastened and shallbe installed outside Zone II, Figure below.303 A readily accessible shut-off valve shall be installed onthe tank. If this is outside the galley, a second valve shall be fit-ted in the fuel line in the galley space, outside zone II, Figurebelow, and not behind the cooker. This requirement does notapply where the tank is located lower than the cooker/heaterand there is no possibility of back siphoning.304 Filler openings for tanks shall be visibly identified to in-dicate the type of fuel to be used with the system.

A 400 Materials near open flame appliances401 Materials and finishes used in the vicinity of open-flamecooking and heating devices within the ranges defined in Fig-ure below, shall comply with the following requirements, tak-ing into account the movement of the burner up to an angle of20° where gimballed stoves are fitted. The requirements do notapply to the cooker itself:

— Free-hanging curtains or other fabrics shall not be fitted inZone I or II.

— Exposed materials installed in Zone I shall be glass, ce-ramics, aluminium, ferrous metals, or other materials withsimilar fireproof characteristics, or be thermally insulated.

— Exposed materials installed in Zone II shall be glass, ce-ramics, metals, or other materials with similar fireproofcharacteristics, or be thermally insulated from the support-ing substrate to prevent combustion of the substrate, if thesurface temperature exceeds 80°C.

B. LPG installationsB 100 General101 LPG systems shall be in accordance with ISO 10239,which covers

— working pressure of the system— stowage of gas containers— material and routing of LPG supply line— installation, ventilation— appliance and their connection— leakage tests.



CHAPTER 6

OUTBOARD ENGINE INSTALLATIONS

CONTENTS PAGE

Sec. 1 Outboard Installations .............................................................................................................. 81

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SECTION 1 OUTBOARD INSTALLATIONS

A. GeneralA 100 General101 Vessels equipped with outboard engines shall complywith the requirements in this chapter in addition to the relevantrequirements elsewhere within these regulations.102 Vessels equipped with outboard engines with a powerexceeding 15 kW shall be equipped with permanent wheelsteering. Permanent wheel steering may be required for othervessels if found necessary for safety reasons. Rudder stopsshall be fitted when wheel steering is fitted. 103 The steering force K on an outboard engine shall not betaken smaller than:

K = 10 P (N) where P is the engine power in kW. 104 Consoles and all components at the steering positionshall be built, stiffened and secured in such a way that they canabsorb the forces to which they are exposed, including dynam-ic loads from the helmsman considering the vessels movementin seas.

105 If it can be established that flame dampers, carburettorsor other components in the engine system represent a safetyhazard, these may be required to be improved or replaced.106 Penetrations to the engine well for outboard enginesshall be effectively sealed by means of rubber sleeves or simi-lar equipment.107 Petrol tanks shall be installed in a separate enclosurewith natural ventilation to the outside of the vessel. Gastightsubdivision shall at least be carried up to adjacent accommo-dation structure, e.g. seat, bench, floor, etc. which lead to openair. Filling pipes shall be fitted and carried to open deck. Petroltanks shall be secured to the hull structure. Loose "carry-on"-type tanks are not permitted.108 Petrol tanks shall be fabricated from steel or aluminium.Diesel tanks shall be fabricated from steel, aluminium or FRP.All couplings shall be fitted to the top of the tank. Petrol tanksshall not have any arrangement for drainage.109 In fuels systems for petrol all metallic components, fromfilling spigots on deck to, and including the engine, shall beconnected by means of electric conductor(s).

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CHAPTER 7

CRAFT WITH NOTATION PASSENGER

CONTENTS PAGE

Sec. 1 Craft with Notation Passenger .................................................................................................. 85

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SECTION 1 CRAFT WITH NOTATION PASSENGER

A. ApplicationA 100 General101 In the present section additional requirements to craftwith notation Passenger are given.

B. Passenger accommodationB 100 General101 The headroom in passenger accommodation shall be atleast 1.98 m.102 Passageways to accommodation spaces and betweenrows of seats shall normally be at least 900 mm wide. Thewidth of door openings and stairways shall not be smaller than760 mm. 103 At least two toilets facilities with light, separate ventila-tion and wash basin with hot water and drain, shall be arrangedwhen number of passenger exceeds 50.104 Adequate space for stowage for personal effects shall beprovided.105 Open decks where passengers may be present shall besurrounded by bulwark or permanent rail at least 1 000 mmhigh.106 Accommodation space(s) shall be ventilated. Naturalventilation can be considered acceptable if the cross sectionalareas of each of inlet and escape are at least 7.5 cm2 per pas-senger. If natural ventilation is not sufficient the space shall beequipped with mechanical ventilation providing at least 6 re-placements of the air volume per hour.107 Equipment shall be provided to allow safe boarding and,e.g. by means of gates and railing.

C. Emergency exitsC 100 General101 Accommodation spaces shall in addition to the normalpassageway exit/entrance have at least one emergency exit.The distance from any location in the space to one of the exitsshall not be longer than 4 m. 102 Emergency exits may consist of a door, hatch or sidescuttle/window to open deck. The light opening of the exitshall not be smaller than 760x600 mm.

D. Intact and damaged stabilityD 100 General101 Craft shall be arranged such that flooding under the load

waterline in:

— stem— bottom forward in craft with speed >25 knots— bottom aft in craft with protruding rudder or propeller,

does not lead to immediate flooding of adjacent compart-ments.The latter is to be serviced by the bilge system operatedfrom the engine compartment. 102 The angle of heel shall not exceed 10° and the freeboardis not to be less than 200mm, when the maximum number ofpassengers is placed in side of the craft with minimum distri-bution 300kg/m2 and no weights closer than 0.2 B to the cen-treline.

E. Fire safety

E 100 General101 The engine room shall be enclosed with fire protectionof minimum 30 minutes rating.102 For craft carrying more than 30 passengers, acoustic andthermal insulation shall be fabricated from non-combustiblematerials.103 Interior surfaces and floor coverings shall be fabricatedfrom materials with low flame spread.104 Upholstery and textiles shall be fabricated from materi-als with low flame spread.105 Fire detection systems shall be fitted in enclosed spacesin the accommodation area, e.g. toilets etc. 106 For craft carrying more than 36 passengers a fixed fireextinguishing system shall be fitted in the accommodation ar-ea. Such a system need not be fitted if all of the following con-ditions apply:

— smoking is prohibited— no galley is fitted— the duration of the voyage is shorter than 2 hours.

107 As an alternative to the fixed fire extinguishing system,a power driven fire pump and fire hose(s) may be fitted capableof reaching the whole craft. The capacity of the fire pump withhose shall not be less than 2/3 of the capacity of the bilge sys-tem as specified in Ch.5 Sec.4 B104. The fire pump shall beconnected to a power source able to supply the fire pump at thespecified capacity for at least 30 min.108 Openings for ventilation of the engine room shall beequipped with closing devices operable from the outside of theengine room and shall be insulated to the same rating as thesurrounding structure.

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DNV Standard for Certification 2.21 Craft

Documents

Transcript of DNV Standard for Certification 2.21 Craft