National Defense Defence nationale Maritime Engineering Journal · 2017-03-06 · Maritime...

1*1 National DefenseDefence nationale

MaritimeEngineeringJournal

June 1995

CPF Construction — Experience Gained

Also:• Readership Survey Results• Incident at Sea: O2 Explosion

in Cormorant

Canada

Last of the ISLs

Looking backat HMCS Fraser...... see page 24

MaritimeEngineeringJournal Established 1982

Director GeneralMaritime Equipment ProgramManagementCommodore F.W. Gibson

EditorCaptain(N) Sherm EmbreeDirector of Marine and ElectricalEngineering (DMEE)

Production EditorBrian McCulloughTel.(819) 997-9355Fax (819) 994-9929

Technical EditorsLCdr Keith Dewar (Marine Systems)LCdr Doug Brown (Combat Systems)Simon Igici (Combat Systems)LCdr Ken Holt (Naval Architecture)

Journal RepresentativesCdr Bill Miles (MARPAC)

(604) 363-2406Cdr Jim Wilson (MARLANT)

(902) 427-4810CPO1 Jim Dean (NCMs)

(819) 997-9610

Art Direction byIvor Pontiroli, DCA 2-6

Translation Services byPublic Works and Government ServicesTranslation BureauMme. Josette Pelletier, Director

JUNE 1995

DEPARTMENTSGuest Editorial

by Capt(N) J.R.Y. De Blois 2

Commodore's Cornerby Commodore F.W. Gibson 3

FORUM

• Combat System Damage Controlby LCdr Bruce Grychowski 4

FEATURESCPF Construction — Experience Gained

by Capt(N) B. Blattmann and Cdr H.V. Archibald 5

Incident at Sea: Oxygen System Explosion in HMCS Cormorantby LCdr Jim Muzzerall, Stephen Dauphinee and LCdr Kevin Woodhouse 13

Survey says!by Brian McCullough 18

Interference Suppression using an HF Adaptive AntennaReceiving System (HFAARS)

by Lt(N) Michael P. Craig 20

GREENSPACE:Hydrogen Sulphide Gas — A Deadly Shipmate

by Lt(N) K.W. Norton 22

LOOKING BACK:HMCS Fraser — Last of the ISLs

by Brian McCullough 24

NEWS BRIEFS 26

OUR COVERCPF construction at Saint John Shipbuilding Limited: (clockwise from left)accuracy control personnel at work in the dock during erection of a bow-section megamodule; a crane manoeuvres a unit outside SJSL's enormousModule Hall; HMCS Halifax under construction. (Photos courtesy of SaintJohn Shipbuilding Limited)

The Maritime Engineering Journal (ISSN 0713-0058) is an unofficial publication of the Maritime Engineers ofthe Canadian Forces, published three times a year by the Director General Maritime Equipment ProgramManagement with the authorization of the Vice-Chief of the Defence Staff. Views expressed are those of thewriters and do not necessarily reflect official opinion or policy. Correspondence can be addressed to: TheEditor, Maritime Engineering Journal, DMEE, National Defence Headquarters, MGen George R.Pearkes Building, Ottawa, Ontario Canada K1A OK2. The editor reserves the right to reject or edit any edi-torial material, and while every effort is made to return artwork and photos in good condition the Journal canassume no responsibility for this. Unless otherwise stated, Journal articles may be reprinted with proper credit.

MARITIME ENGINEERING JOURNAL. IUNE 1995

Guest EditorialMAREs — Systems Engineers Bridging the GapBy Capt(N) J.R. Y. De Blois,Director of Maritime Combat Systems

In these times of downsizing andprivatization it is germane to ask our-selves exactly what it is that MAREsprovide to the navy — what is our"value added." Engineering services canbe purchased, after all, so why maintaina naval engineering MOC? Clearly ourworth must go beyond our engineeringqualifications and parade-square skills.

Our value added is based on the com-bination of our particularized technicalknowledge, our knowledge of the ship-board environment and our knowledgeof the departmental material supportsystem. Any single factor is hardly suffi-cient reason to justify a MARE classifi-cation. What is intrinsically valuable isthe MARE's ability to bridge the gapbetween operations, technology andprocess. But how much of each elementis required?

As far as operational exposure isconcerned it is tempting to say there cannever be enough. Without the operationalend of the business there would be noneed for any of us. At the other extreme,if a MARE were to spend an entirecareer at sea (presumably becoming verygood at the job) the operational experi-ence would never be applied to all thoseother jobs MAREs do, nor could otherMAREs gain this experience. The correctanswer is largely academic. Given thefew platforms available for MSEs andCSEs, it is doubtful we will ever over-subscribe to this element.

And what about technical knowledge?How much and what kind? In one sensewe need just enough to cost-effectivelybridge the gap between the operationalrequirement and the suppliers of ser-vices. If the navy operated a fleet of

automobiles instead of warships therewould be no gap. There is a self-sustainingmarketplace for cars, which drives per-formance up and prices down, offeringsome protection to the customer. Forwarships and associated systems this isnot the case. The navy must thereforeretain an indigenous capability to be asmart buyer, a smart user and a smartmaintainer.

"If you are thinkingabout becoming a specialistI would recommend youmake a career changeand make room for areal MARE."

The MARE, then, must be first andforemost a systems engineer capable ofdrawing logically upon the specializedskill sets that are available. In this cli-mate of downsizing we cannot afford tohave specialists in uniform, people whoexpect to spend a career working exclu-sively in software or lubricants. Not thatthese skill sets are not required, but theyare generally best provided by publicservants or contractors. If you are think-ing about becoming a specialist I wouldrecommend you make a career changeand make room for a real MARE.MAREs require the system-levelbreadth and the technical depth to gainaccess to the specialized services avail-able to them. They need not know it all,nor do it all when cost-effective alterna-tives are available, but they must besmart buyers of these services.

And finally, how much experiencedoes a MARE need with departmentalmateriel support? If you include industry

and consider the whole as a system, onceagain the MARE's role is that of asystems engineer. Our value to the navylies in our ability to understand how andwhy a system works so we can exerciseit to the navy's best interest. As MAREs,therefore, we must gain experience andknowledge in all facets of materiel sup-port. Imagine how dangerous it would beif the CSE of a ship were to becomeknowledgable about radars only, thenmake decisions based on radar considera-tions alone without considering theimpact on the entire combat system. Itwould be equally disastrous for organiza-tional elements of the material supportsystem to become totally self-focusedand ignore system impacts as they exer-cise their assigned roles. What's good forthe radar may sink the ship; what's goodfor one unit may be bad for the navy.Junior MAREs are thus expected to pro-vide systems expertise from a technicalperspective, while senior MAREs arefurther expected to provide systemsexpertise from an organizational perspec-tive. Such diversity of employment with-in the materiel support system is a majorelement of the MARE's value added.

Operations, technology, materielsupport — these are just elements of apart of the system we call the navy, but itis our role to know how they fit together.The one-dimensional MARE has nomore place at the materiel organizationlevel than at the technical level. MAREsshould guard against becoming organiza-tional equivalents to the grommet expert,because when all is said and done theessence of the value we provide to thenavy comes from our ability to makethings work together. 4

MARITIME ENGINEERING JOURNAL, JUNE 1995

Commodore's CornerCue cards for the future

By Commodore F.W. Gibson, OMM, CDDirector General Maritime Equipment Program Management

In the last Journal I wrote about thechanges that we were facing and our partin these changes. Since then, NDHQ hascommenced full implementation ofOperation Excelerate and MARCOM hasbegun its implementation of the NavalEngineering Maintenance FunctionalReview (NEMFR). Organizations arechanging, processes are changing —nothing seems to be the same and it is allvery confusing. Is there a master plan?Does anyone really know what is goingon? Let me offer you the keys to whatis happening — the common threadsthroughout all of these changes.

First and most importantly, there isthe need to put in place the wherewithalto make the cost of what we do visible.Measure the benefit of something againstits cost and you will get a pretty goodidea of where it fits into your program.

It doesn't matter if we are the informa-tion gatherer or the decision-maker, noneof us can afford to operate in today'snavy without this vital information.

Second, we need to put our supporton a more businesslike basis to ensurethat it is being offered in the mostcost-efficient manner. Naturally, thisassessment will only be possible if weunderstand what "effective" means andhave the means of measuring its cost.

Third, we have to determine howmuch risk we are prepared to take inproviding our support. Risk is a veryimportant dimension of what we do —targeting zero risk drives up costs; toomuch risk is unacceptable. How manytimes do we have to review somethingbefore we sign it off? The right balancemust be determined in every case.

Cost visibility, businesslike workpractices, risk management — these areour cue cards to what is going on. Ourjob always has been and always will beto deal with change. (You see? Somethings never change.) The challenge is tolive within the constraints and use themto our advantage.

Our opportunity lies in making thechange meet its objectives. That meanspicking up on how it relates to what ishappening around us and running with it.We have to fully embrace this opportu-nity to shape our own future, because ifwe don't, Op Excelerate and NEMFRwill go down in history as nothing morethan personnel-reduction exercises andthe navy will not be getting the supportthat it needs or that it could have. 4

Maritime Engineering JrmruaiObjectives

« To pa>to»t« yrufosiouaiiSiDmaritime rngineers awl

• To provide an. opes; forrim wheretopics of interest to the maritime

- • eugineeiiiif; coDvnitimty ego bjlifjli

presented ami diwaiaal :',v:-u if theymieiit be controversial

To present practical maritaii?eHfdti.ea.to.? articles.

To present historical perspectiveson ettiTem programs. Situationsa ad

JJJ provide announcements ofprograms concerning mantiiiiiBcrightsedrig pmsotmel.

To piovide personnel news noteovercd by official. pubJkMi:ion,s,

Writer's Guide

The Journal we.!.oorn||fisubmissions, in Eji.g.itsL • Fre,i;di, on||||p|f|fl||ipet any Jjj jjjj Staledobjeeuvei. To avoid dupJicRflo;). of effortiinri to ensuie snitabiJHy of subject irwrusyprospective, contubators are strujigiy ' |advised to contact the Editor,Engineering Journal, DMEE, National.Defence Headquarters, Ottawa, Ontario,K1A OK2, Id.fSW) 997-9355, before

submitting raaieriab Final selection ofn tides tor publication is made by theJauinaTs editorial

jfjj a general rote, axcielasbonbi not exceed 12 double- ajjaeedH Hsu, The prefeirsd format Is11 Tr' uKkeife. aee<ji™,«]«edbv one copyof iii.e typescript. 1'he author's itarue, rifle,andress and telephone number sfiouldajjpe?.r on fiffi first pa.se. The last: pagsshould contain eoniplete figure caption;-: far-

riyrug tbe axtiefe. 1'horos and other ?itwoi:f.should not be incorporated ^i f jy :l;e ly^pSseripi; hut slmuM lie pi:otf:{:i.ed siid i.usBrt!xilooge m the triailing envelope. A photo-graph of the aritlior waald be appreciated.

lerurrs ofir.iv ten]-;lli avvelccirne, but only signedH| IM; eotisid.ered. for publication. .


Combat System Damage ControlArticle by LCdr Bruce Grychowski

The Combat System Engineeringdepartment's Emergency Response Teamhas been in place for some time. It has amandate to effect the repair of the com-bat system during all emergency andaction station situations. It says so in theNEM Vol. 2, in the Damage ControlManual and in SSOs. Unfortunately,there is neither direction nor trainingprovided on the conduct of this activity.Sea Training has conducted extensiveexercises with the ERT in all classes ofship and there is a noticeable differencebetween repairing equipment in non-emergency situations and in emergency/action situations. The difference, whichis time, drives the methods, considera-tions and information exchange.

When one thinks of the term damagecontrol, a picture comes to mind of"engineers" battling fires and floods indarkness through clouds of smoke. Theirspeech is garbled by their Chemoxmasks as they drag charged hoses to thescene of the fire or work fiendishly inwaist-deep water (always cold). Theirmotto is Float, move, fight. This is avalid portrayal of damage control, butnot the only one. Move and fight areinterchangeable, dependant upon one'spoint of view and the mission of theship. Clearly, if you are not floatingyou are in a world of hurt. If you canmove but cannot fight, you had bestmove quickly.

Combat systems damage control isthe act of returning a maximum of capa-bility, in a short time, after sufferingequipment loss while the ship is at risk.This does not imply full repair of dam-aged equipment. The cause of the equip-ment loss can be directly from battledamage, fire or flood, shock, loss ofservices or from equipment failure.

Whatever the cause, the damage must beidentified, assessed, isolated, circum-vented and, finally, repaired. The wholeconcept is predicated upon knowing theship, the systems and the situation indetail. If this is not done effectively, thefighting capability of the ship will beaffected and the ship will lie open tomore damage.

Loss of air pressure, cooling water orcooling air can remove equipment fromservice. Interruption of power can notonly take out high-value systems orequipment, but even after power isrestored software must be reloaded andstarting-time delays must be waited out.Fire, flood and physical stress will createnumerous types of failure includingcable/connector damage, electrical short-circuiting, thermal shutdown and physi-cal damage. Effective plans, proceduresand training are required to counter eachsituation and return as much capabilityas possible. In the short duration of mod-ern attacks there may not be time tocomplete normal corrective maintenance,but there will be time to work aroundthe problem and this is combat systemdamage control.

How do you train for CS damagecontrol? What tools and equipment arerequired? Where is the guiding docu-mentation and who is in charge? To mymind, the documentation should be con-tained within the NEM Vol. 2 and theDamage Control Manual. The control-ling authority must be in a senior head-quarters and be an active member of theDamage Control Advisory Committee(DCAC) and its working group(DCACWG). There should be a subcom-mittee to review CS damage control con-cerns, while keeping strong ties to theDCAC. Tools and equipment must bederived from detailed analysis of damagescenarios. Communications, ERT posi-tioning, state boards, information storage/

retrieval and manning must also bederived from scenario analysis. Trainingmust become an integral part of careercoursing for CSE officers, chiefs andPOls, with occasional specific refreshertraining for all CSE department personnel.

Combat system damage controlrequires specific guidance to become aprofessionally competent activity. To dateit has been purely up to individual ships'Combat Systems Engineering depart-ments to come up with ad hoc systemsand equipment to do the job. The resultshave been varying. As there is no stan-dard, the utility of the ERT in its CSdamage control role has met with someskepticism from commanding officersand Combat departments. Sea Traininghas effected minor advances which haveimproved effectiveness and establishedmore of a team approach, but the advan-tages are lost with every major personnelchange. It is therefore time to do some-thing about the situation formally.

I am writing this article to identify aproblem, not to offend any person ororganization; the topic needs exposure.The CSE departments in ships are doinga fine job in isolation, but they needsome assistance, training and tools to dotheir brand of damage control effectivelyand professionally. Functional warshipsare our reason for being and it seems thatwe, collectively, outside of ships, havenot paid sufficient attention to an impor-tant part of the aim. £

LCdr Grychowski is the Sea Training AtlanticCSEO.


Canadian Patrol Frigate ConstructionExperience Gained*Article by Capt(N) B. Blattmann and Cdr H.V. Archibald

Photographs appear courtesy of Saint John Shipbuilding Limited

(*Condensed from the authors' paper presented to the 1994 East and West Coast MARE Seminars.)

Saint John Shipbuilding Limited(SJSL) built the first Canadian patrolfrigate (CPF), HMCS Halifax, in fiveand a half years. By comparison, thefifth frigate built by SJSL, HMCSFredericton, took only three and a halfyears, with an incredible 45-percentreduction in construction manhours.SJSL predicts that the last CPF, HMCSOttawa, will be built in just three yearswith fewer than 50 percent of the man-hours used to build Halifax. As a resultof this performance, SJSL will bring theCPF project to completion within budgetand schedule.

This is a tremendous achievement forCanada's largest-ever government pro-ject, especially considering it takes nearlythe same number of manhours to refitfive steamers as it takes to build onepatrol frigate. This article aims to dem-onstrate how advanced ship-constructiontechniques have been used to recoupinitial overruns and make the CanadianPatrol Frigate project a success story.It will also draw some lessons from theexperience which we in the naval engi-neering community can use to our bene-fit in future projects.

SJSL Construction Experience:The Approach

In the traditional approach to shipdesign and construction, the varioussystems such as propulsion, ventilation,piping, electrical, etc., are designed anddrawn separately. Production work pack-ages are system oriented and the ship-yard work-force is similarly split intospeciality shops, with the majorityof outfitting done after the ship's hullis erected.

In 1984, during the early stages of theCPF detailed design development, SJSL(with support from DND) revised thistraditional approach by incorporatingadvanced ship-production techniques.

Taking advantage of a broad applicationof pre-outfitting techniques, SJSL wouldemploy a product-oriented approach(rather than a system approach) com-monly referred to as "product by stage ofconstruction," or P/SC.

In P/SC the ship is constructed as aseries of building blocks. The shipdesign is divided into parts and subas-semblies, or "interim products," whichare then grouped according to their pro-duction requirements. Product similarityallows statistical analysis to be used tocontinuously improve product accuracyand the overall quality of the ship. Theshipyard is organized into work centresor stages that cater to this process. Theinterim products are eventually mergedto form larger assemblies and so on ina production-line process. The overallgoal is to attain the least cost and theshortest possible construction periodthrough optimization of the process offabrication, assembly and erection ofthe interim products.

Maximizing the amount of outfittingdone prior to the ship being erected isespecially important in countries such asCanada where the weather is not alwaysconducive to outdoor work. As a rule ofthumb, if doing a job at the optimumtime in the shop takes one hour, it willtake three hours to do the same job at anon-optimum time, five hours in thegraving dock and seven hours at the out-fitting pier.

Still, it requires a major redirection ofcompany resources to implement thesetechniques and accommodate therestructured build sequence from whichthese efficiencies are drawn. Suchchange places extensive demands on theengineering, planning and procurementfunctions since it requires their productsearlier in the construction sequence. Ineffect, a new approach to design andconstruction must be implemented totransform the traditional system designinto the products for a P/SC approach(Fig. 1).

TRADITIONAL APPROACH:

PHASED APPROACH FOR P/SC:

Fig. 1. Ship Design Stages


Fig. 2. SJSL Facility Layout

Designing a Canadian warship fromscratch was not easy. Not only were thespecification requirements stringent, butmore than 20 years had passed since amajor warship was last designed andbuilt in this country. Not surprisingly,substantial delays were soon encounteredin completing the various design phases(including final production drawings),especially once the decision was made tochange to a P/SC approach midwaythrough the design process. The deliverydates also suffered as construction of thefirst CPFs proceeded while the detaileddesign was still being finalized. To illus-trate how SJSL was able to turn aninitial, adverse situation around andmake the CPF project a success, it

is instructive to review the successionof construction techniques used duringthe project.

HMCS Halifax (Baseline)

On June 8, 1986 when the first steelwas being cut for HMCS Halifax, theSJSL facilities included the longest dry-dock in Eastern Canada (Fig. 2). Thethree cranes that serviced the dock werecapable of lifting about 200 tonnes ontothe building blocks. The major steel-work, assembly and pre-outfit activitieswere carried out in the steelwork assem-bly building, a 285-metre-long structurewhich had been recently upgraded withthe installation of a plasma cutter, two

Fig. 3. SJSL Production Flow

MK automatic dual-head stiffener weld-ers and better cranage. The pipe shop,one of several shops to be moved to newfacilities on the other side of the dock,was upgraded with automated pipe-bending machines.

SJSL applied the P/SC principles inthe construction of Halifax by dividingthe ship into four zones — bow, machin-ery spaces, stern and superstructure —and determining the best point at whichto do the work in each zone. The workitself was broken into eight stages corre-sponding to the work centres in the yard.The ship was then subdivided intogroups of similar parts, or interim prod-ucts, which could be manufactured andinstalled in batches at the most logicaltime and stage (Fig. 3~).

Halifax was constructed of 57 assem-bly units, each typically one deck highwith at least one major transverse bulk-head. The assembly units were joinedinto two, three and four deck levels toform 26 partially outfitted erection units(Figs. 4 and 5) which were erected inthe graving dock to form the ship. Onceerected, the ship was floated-up andshifted forward in the dock for finaloutfitting and to allow the next ship tostart erection.

The construction phase (from start offabrication until float-up) was originallyscheduled to last 19 months. WithHalifax, however, this phase lasted23 months, the four-month slippageoccurring during unit erection. Similarly,the overboard phase from float-up todelivery dragged on to 37 months fromthe scheduled 20 months, extending thescheduled three-and-a-half-year marchto provisional acceptance to more thanfive years. The overriding difficulty, inour opinion, was that the developingdesign was not keeping pace with theoverall schedule, resulting in a lowerlevel of pre-outfitting, interference prob-lems and problems with accessibilityand maintenance. It all made for a sig-nificant amount of rework, such as whenSJSL had to refigure cable transits thatwere already full because cables hadbeen installed before the cable-rundrawings were complete.

HMCS Vancouver

The first steel for the second frigate,HMCS Vancouver, was actually cut twomonths ahead of schedule, close onthe heels of that for Halifax, on Dec. 6,1986. SJSL had learned from its


experience with Halifax and wanted toextend the fabrication time to achieve ahigher level of pre-outfitting. Unfortu-nately, because of the narrow separationbetween the two ships, Vancouver suf-fered from many of the same problemsexperienced by the lead ship. Asproblems were found in Halifax, soattempts were made to correct them inVancouver, causing it to be delayed bysix months in fabrication.

•

It!Fig. 4. HMCS Halifax Assembly Unit

It took 18 months before the keel waslaid versus the 12 months originallyscheduled, in contrast to the eight monthsfor Halifax. Final erection and comple-tion of the construction phase weredelayed a further three months, makingthe ship a total of seven months late atfloat-up, even with the two-month headstart. The additional pre-outfitting inVancouver did, however, translate intosignificant manhour savings. The shiprequired some 12 percent fewer man-hours than did Halifax (Fig. 6). Still, theamount of rework associated with designrevisions made Vancouver two years latein delivery (Fig. 7).

HMCS Toronto

Due to the problems being experiencedwith the construction of the first twoships and because Vancouver was takinglonger to fabricate than expected, SJSLdelayed the start of steel fabrication forHMCS Toronto (designated CPF-04; thethird to be built by SJSL) to allow engi-neering and design to catch up. The firststeel was finally cut for SJSL's third shipin January 1988, one year after that forVancouver, four months later than origi-nally planned.

About this time SJSL decided toexpand its facilities and implement

ERECTION UNIT

CONSTRUCTION

MEGAMODULES

a "megamodule"concept. This, theyhoped, would increasethe level of pre-outfitand provide an oppor-tunity to maximize theamount of work thatcould be done in aconsiderably moreproductive, controlledenvironment. In April1988 work began on amodule assembly hall(see front cover) thatwould replace thetemporary shelters(Fig. 8) under whichthe erection units forthe first two frigateshad been completed.The building was inplace by February1990 and allowed the26 erection units to becombined into ninemegamodules (Fig. 5) in the assemblyhall prior to erection. To get these newmegamodules into the graving dock,SJSL leased two 350-tonne Scheurletransporters and a Manitowac ringercrane with a lift capacity of 600 tonnes.The yard was now able to build unitsin excess of 450 tonnes, a significantincrease over the previous 200-tonnelimit.

Changing the building process so rad-ically just as the yard was gaining expe-rience in the erection-unit concept was amajor risk, but one which senior man-agement was prepared to take. They

Fig. 5. Megamodule vs. Erection Unit Construction

realized that without a radical revision ofthe process they would simply neverrecoup the delays that had already beenexperienced. Toronto became the first ofthe CPFs to benefit from the new processwhen four erection units forming the bowwere combined into a 350-tonne mega-module. In October 1990 the megamod-ule was lowered into the dock on eight125-mm-thick Kevlar slings — a first inshipbuilding. Until then, heavy lifts hadalways used conventional steelwire rope.To position the megamodule in the dock,a hydraulic control system was usedinstead of the slow, labour-intensive,chain-block method.

120%

100%

01 02 04 07 08 12

12% LEARNING

FROMCPF-01 FROM CPF-04 FROM CPF-07

MEGAMODULE SAVINGS = 1.5 MILLION MANHOURS

Fig. 6. SJSL Learning Curve


CPF-01HALIFAX

CPF-02VANCOUVER

CPF-03VILLE DE QUEBEC

CPF-04TORONTO

CPF-05REGINA

CPF-06CALGARY

CPF-07MONTREAL

CPF-08FREDERICTON

CPF-09WINNIPEG

CPF-10CHARLOnETOWN

CPF-11ST. JOHN'S

CPF-12OHAWA

S.A.

S.A.

S.A.

S.A.

S.A.

S.A.

S.A.

S.A.

S.A.

S.A.

S.A.

S.A.

CPF SCHEDULE

START FAB

31-May-8608-Jun-86

14-Feb-8706-Dec-86

02-May-8725-May-87

26-Sep-8716 Jan-S8

07-Nov-8711-Aug-88

06-Feb-8821-Feb-89

17-Dec-8814-Jan-89

17-Mar-9003-Jul-90

15-Dec-9002-Jul-91

07-Dec-9119-Apr-92

26-Sep-9226-Jul-92

05-Jun-9331-May-93

KEELLAYING

14-Mar-8719-Mar-87

06-Feb-8819-May-88

17-Oct-8817-Jan-89

17-DCC-8824-Apr-89

18-Jun-8806-Oct-B9

18-Jun-8815-J«n-91

13-Jan-9fl08-Feb-91

10-Nov-9fl25-Apr-92

24-Aug-9119-Mar-93

11-Jul-9218-Dec-93

22-May-9324-Aug-94

29-Jan-94(27-Apr-95)

FLOAT-UPOR LAUNCH (L)

Q9-Jan-8830-Apr-88

10-Dec-8808-Jul-89

27-May-8916-May-91 (L)

21-Oct-8918-Dec-90

19-May-9025-Oct-91 (L)

24-Feb-9026-Aug-92 (L)

29-Jun-9126-Feb-92

21-Mar-9213-Mar-93

19-Sep-9211-Dec-93

18-Sej>-9331-Oct-94

11-Jun-94(4-JUI-95)

18-Mar-95(24-Dec-95|

STARTSEA TRIALS

2Q-May-8906-Aug-90

12-May-9010-Feb-92

ie-Jun-9016-May-93

15-Dec-9021-Sep-92

15-Jun-9127-Nov-93

11-Jan-9219-Jun-94

19-Sep-9220-Jun-93

12-Jun-9323-Jan-94

12-Mar-9406-Sep-94

17-Dec-94(27-Mar-95|

16-Sep-95(13-Nov-95)

15-Jun-96(27-May-96|

NOTES:S=CONTRACT SCHEDULED DATE (pre OAA)A.=ACTUAL DATE|)=CURRENT TARGET DATES*28 JUNE 91 was Provisional acceptance For CPF-01. Final Acceptance was 23 Dec 92.

DELIVERY

2S-Oct-89*28-Jun-91

24-Sep-9011-Sep-92

29-Jan-9123-Sep-93

29-Apr-9123-Dec-92

15-0ct-9102-Mar-94

29-Apr-9230-Aug-94

29-Dec-9227-Jul-93

29-Sep-9324-Feb-94

29-Jun-9411-Oct-94

29-Mar-95(28-Apr-95|

29-Dec-95(10-Dec-95)

29-Sep-96(30-Jun-96)

Fig. 7. Schedules: Contracted, Actual and Projected

By float-up the initial four-monthdelay on Toronto had increased to14 months, mainly because of resourcelimitations as Halifax and Vancouverwere both undergoing final IMCS andcombat outfitting and trials. Still, SJSLmade good use of Toronto's lengthenedconstruction phase to improve its con-struction techniques and set up theplanning for megamodule construction,further increasing the level of pre-outfit-ting. For example, the almost 25-percentrejection rate of randomly X-rayedwelds on Halifax was reduced to fivepercent on Toronto. Although the shipwas 20 months late when delivered onDec. 23, 1992, Toronto required about18-percent fewer manhours thanVancouver.

HMCS Montreal

Having demonstrated the feasibilityof using and safely handling megamod-ule units, SJSL proceeded to build

HMCS Montreal (CPF-07), using sixmegamodules and 11 conventional erec-tion units (Fig. 9). Fabrication started ayear after Toronto on Jan. 14, 1989,only a month behind the originalschedule, but erection did not beginuntil Feb. 8, 1991, almost 13 monthsbehind the original non-megamoduleschedule. In contrast to Toronto, thisdelay was primarily due to SJSL insti-tuting new processes and maximizing itsopportunities to push more and morework into the construction phase versusthe overboard phase.

Of the six megamodules used inMontreal's construction, perhaps themost interesting to engineers is megaone, the bow unit. Building on theirexperience, SJSL investigated the fea-sibility of installing the entire gun in theshop (Fig. 10) before moving the mega-module to the graving dock. This was aradical move, as gun installation andalignment had always been done after

erection. SJSL's bold step became aworld "first." The concern had alwaysfocused on being able to meet final gunalignment, but SJSL succeeded thanksprimarily to its accuracy controldepartment.

Accuracy control holds a unique andcritical position within SJSL by virtue ofits involvement throughout the shipyard.The accuracy control team monitorsnearly every process from steel cuttingto megamodule erection. The numericaldatabase the team collects provides sta-tistical information which the planning,welding and production departments useto implement innovative productionmethods. For instance, this data wasused to improve welding sequences andreduce distortion and subsequent out-of-tolerances between units, providing theshipyard with the necessary confidenceto initiate megamodule construction.

In addition to incorporating sixmegamodules in Montreal, SJSL alsomoved as much work as possible intopre-outfitting. For instance, they recog-nized that grinding, painting and otherrework caused by hot work done afterblast and paint contributed significantlyto construction costs and represented anarea of large potential savings. This wasbut one of the many items addressedjust prior to Montreal's constructionby SJSL's Continuous ImprovementProgram, a program similar to the TotalQuality Management initiatives going onin the navy. As a direct result of this pro-gram, a number of producibilityimprovements were introduced duringthe construction of Montreal.

Montreal thus became the first ship tobenefit significantly from megamoduleconstruction and the ContinuousImprovement Program. When the firstunit was erected the ship was about13 months behind schedule but by float-up on Feb. 6, 1992 five months of thatslippage had been picked up. For thefirst time the company was also able tomake up schedule in the overboardphase, so that by delivery on the July 27,1993 Montreal was only seven monthsbehind a schedule that had been estab-lished six years earlier. These scheduleimprovements marked a turning point inthe project and were the harbinger ofthings to come. SJSL was once againable to post a reduction in productionmanhours, this time more than 14 per-cent compared to Toronto.


Fredericton, Winnipeg andCharlottetown

The trend continued with HMCSFredericton (CPF-08), the fifth patrolfrigate from SJSL. The ship was the firstto be built almost entirely of megamod-ules (eight of them) and required about12 percent fewer manhours to build thandid its predecessor. One of the new meg-amodules, number seven — bridge, opsroom, galley and mast — weighed awhopping 450 tonnes, the limit of SJSL'slifting capacity (Fig. 11). Pre-outfittingreached a new level in mega eight:uptakes were now fully lagged, spaceswere painted and final inspectionswere done prior to erection in thegraving dock.

From the start of fabrication to deliv-ery the total time was just over three anda half years, an excellent achievement.For the first time SJSL had also reducedthe construction phase (Fig. 12), andbelieved it could shorten constructionenough on future CPFs to catch up toschedule by CPF-10 (HMCS Charlotte-town) and deliver the last two ships early.

SJSL instituted additional improve-ments with Winnipeg's (CPF-09) pre-outfit, especially on the hangar module(Fig. 13). The CIWS, torpedo handlingequipment, after STIR and communica-tion antennas were all installed as pre-erection work, thereby negating the needfor Paramax to perform these tasks out-doors. By the time the hangar waserected it was 85 percent complete.

Fig. 8. HMCS Halifax Temporary Shelter

Another improvement was the finalizationof the main ring butt welds on all mega-modules in the shop, allowing main ringwelding to proceed as soon as the mega-module was positioned in the dock.

By the time Winnipeg was deliveredin late 1994 the manhours had beenreduced again by nearly eight percent,substantiating SJSL's claim that, begin-ning with the true megamodule approach

NEW MEGA

MEGA 6394 TONS

MEGA 5 MEGA 4 MEGA 3390 TONS 263 TONS 4Z5TONS

ZONE 3

START-FLOAT

FLOAT-DELIVERY

ZONE 2

(38 MONTHS)

(17 MONTHS)

ZONE1

CONTRACT ACTUAL

Fig. 9. HMCS Montreal Construction and Schedule

on Montreal, a new 12-percent learningcurve for ship construction had begun.The difference between a typical12-percent curve starting from Torontoand the current projections starting fromMontreal (Fig. 6) are attributable directlyto megamodule construction and amountto a substantial 1.5 million manhours!Thus the daring initiative undertaken bySJSL in the early nineties is quite clearlypaying off.

SJSL has continued to subject themegamodule methods to reviews aimedat maximizing efficiency. For example,beginning with HMCS Charlottetown,SJSL's seventh ship, mega three has beenenlarged to include the forward auxiliarymachinery room, saving a month of docktime per ship. The move significantlyimproves the installation of pipe work,cabling, etc., from the diesel generators,auxiliary boilers, ROD units and otherequipment through to the forwardengine-room (Fig. 14). To save moretime, Charlottetown's tanks were, for thefirst time, air-tested in the module hallinstead of water-tested. Also, the ORESBall was installed in the uptakes priorto erection of mega eight. By the timeCharlottetown was floated-up in October1994 the ship was estimated to be 69.3-percent complete — the highest level offinish achieved by that stage at that pointin the CPF building program. As a resultof these improvements Charlottetown is


Fig. 10. Megamodule 1 with Gun

expected to be delivered to the navy byApril 1995, only one month after thedate projected back in 1987.

Even though the project is nowdrawing to a close, SJSL has not easedin its drive to improve. An additionalManitowac ringer crane will be installedin the spring of 1995 to increase theyard's lifting capacity to 800 tonnes.Current plans are to increase the size ofthe megamodules for HMCS Ottawa,our twelfth and last CPF. These plansinclude combining megas four and five,as well as installing the gearbox, gasturbines and raft in mega three prior toerection. A further proposal to create two"super" megamodules out of megas two,seven and eight is also being studied(Fig. 15). These changes are designed toimprove productivity and reduce con-struction time and should help SJSLavoid the "last-ship syndrome" commonin other multiship programs.

Lessons Learned

Benefits of Advanced Ship Construction

The most obvious lesson to belearned from the SJSL CPF experience isthat there are significant benefits to begained by maximizing pre-outfitting in ashop environment. SJSL clearly demon-strated that these benefits — reducedconstruction cost, improved quality andreduced construction time — are notlimited to a yard with an experiencedwork-force. Rather, they can be attainedthrough rigorous planning and a motivat-ed management cadre implementing

good, basic industrial engineering con-cepts. By successfully implementingthese techniques and practices, SJSL hasestablished itself as a competitive forcein the world shipbuilding marketplace.

Design Process

The second lesson involves the waywe do business. As many people areaware, the procurement strategy for theCPF project was a significant departurefrom previous experience. A TotalSystems Responsibility(TSR) approach wasadopted whereby thecontractor was respon-sible for all aspects of theproject, includingcontract and detaileddesign. The intent wasthat the contractor wouldproduce frigates meetingour performance require-ments in a "turn-key"project. To ensure thegovernment's indepen-dence, a policy called"negative guidance" wasfollowed during the pro-ject definition phase. It isthis negative guidanceapproach which needs asecond look since thefallout was that govern-ment and industry did notproceed as partners, butalmost as independententities during the earlyphases of the project.

Such an environment is not conduciveto the implementation of producibilityconcepts involved in a P/SC approach.These require co-operation between thenavy and the shipbuilder from the earli-est stages to provide a receptive atmos-phere for the necessary trade-offs to bemade and implemented fully.

The benefits of incorporating produ-cibility concepts and strategies from theearliest stages was amply demonstratedin the CPF project. But with the signifi-cant savings being realized only afterthe delivery of CPF-07, Montreal, thereal disappointment is in not achievingthe full potential that might have beenpossible had the new concepts beenincorporated during the earliest stagesof the design process. Several otherinitiatives might also have been consid-ered, such as the "robust ship" with itsheavier, but simpler structure, but theserequire the shipbuilder's early participa-tion in the design process to foster con-current product and process design. Inthe case of CPF the design of the con-struction process did not start until wellinto the actual detailed design and didnot really conclude until after theseventh ship. Producibility and con-struction-process considerations arerequired in all design phases prior toconstruction.

Fig. 11. Megamodule 7 Superstructure

10MARITIME ENGINEERING JOURNAL. JUNE 1995

SHOP/DOCK

FLOAT

I AFLOAT/TRIALS

Halifax (CPF-01)

Vancouver 1021

Toronto (01)

Montreal (07)

Fredericton (08)

Winnipeg (09)

Charlottetown (10)

St. John's (HI

Ottawa (12)

60

67

59

54

44

33

29

27

26

50 40 30 20 10 10 20 30 40 50

• TIME SCALE IN MONTHS

MORE TIME IN THE SHOP, LESS TIME AFLOAT

Fig. 12. SJSL Shipbuilding Durations

The concept of involving the ship-builder earlier in the design process isone which the USN is currently pursu-ing in its quest to improve the efficiencyof its ship design and construction pro-cess and make that process both shorterand cheaper. Our navy is also consider-ing it in the initial concepts for a multi-role support vessel (MEJ June 1994)process including a combined designteam of contractor and naval personnel.Nonetheless, there also needs to be aconsistent, systematic approach to meas-uring the impact of producibility con-cepts. Criteria must be developed toenable producibility trade-offs to bemade so that the navy is assured of get-ting the end product it desires. If this isto succeed, it will require training forboth naval and contractor engineers.

Lead-ship Strategy

Another lesson which stands out isthe need to separate the lead ship fromfollow-on ships. The original contractallowed a gap of only one year betweenthe delivery of the first and secondships. The problems caused by thissmall separation were compounded bythe fact that the original schedule allot-ted only three years to build each ship.We know now that the time needed toconstruct a typical lead frigate is aboutfive years and even in the best of timesthe first follow-on ship will requireabout four years. Thus, from the leadship to the follow-on ships, the stagewas laid for the repetition of engineering

and material problems and attendantrework charges. The situation got worseas the detailed design began to slide tothe right into the actual constructionperiod of the follow-on ships. The resultwas that the early portion of the contractschedule soon became completely unre-alistic and the contractor had difficultypredicting delivery dates and the man-hours required to complete each ship.

Changes and rework must beexpected on any new construction pro-ject, but a significant number of man-hours might have been saved if therehad been more separa-tion between the firsttwo ships. Based on theCPF experience, a casecould easily be made forsupporting a prototypeapproach. With anappropriate gap betweenthe delivery of the leadship and the first of thefollow-on ships, themajority of constructionand design faults couldbe identified and elimi-nated before full produc-tion was undertaken.Certainly, if not a separ-ate contract, whichmight be impractical forreasons of shipyardemployment continuity,then completing thedetailed design priorto fabrication and

maintaining a significant separation aremandatory. This might well be the mostimportant lesson of the CPF project.

Conclusion

The original project objectives were to(a) build new multipurpose warships tomeet naval requirements, (b) establishindustrial benefits for Canada, and(c) create a shipbuilding centre-of-excellence in Canada. The CPF designand performance are indeed a successstory. HMCS Halifax has now sailedover 40,000 nautical miles and is highlycapable of extended operations at sea inall weather conditions. Halifax, Torontoand Montreal have been deployed on UNpeacekeeping duties in the Adriatic Sea,while Vancouver has served in the FarEast as an integrated component of a taskforce. As one CPF commanding officerremarked on his return from his firstextended deployment, "It is becomingapparent that the CPFs are going to beequal to or better than any comparablysized multipurpose warship in the world."

The Canadian Patrol Frigate projecthas generated significant industrial bene-fits, with over 70 percent of the workdone in Canada. At the height of produc-tion the prime contractor and its principalsubcontractors alone were employingmore than 6,000 people directly on theproject. Of the more than 200 Canadiancompanies supplying equipment tothe ships and support facilities, manybecame success stories in their own right.

; .

Fig. 13. HMCS Winnipeg Hangar

MARITIME ENGINEERING JOURNAL, JUNE 1995 11

Perhaps most importantly, SJSL nowhas a modern shipbuilding facility andthe proven capability to design and buildfirst-class ships efficiently and economi-cally. There were many examples wherethe navy and SJSL worked together tomake changes beneficial to both parties.This capability is not only nationallyimportant, but is now recognized interna-tionally. SJSL is presently pursuing anumber of foreign marketing opportu-nities, any one of which could putCanada back on the map as a shipbuild-ing nation. Thus, through leadership,innovation and achievement SJSL hasrightly earned the title of ShipbuildingCentre of Excellence, for which we asCanadians can justifiably be proud.

Acknowledgment

We would like to acknowledge thesupport received from Saint JohnShipbuilding Limited and from the CPFProject Management Office in Ottawa.In particular, we would like to thankMr. Deny Oke, Mr. Daniel Cyr andMs. Mary Parsons, all of whom assistedwith comments and suggestions thatwere invaluable in the preparation ofthis paper. £

CPF SUPER MEGAMODULES

PROPOSEDSUPER MODULE 8/7

SUPER MODULE

PROPOSEDSUPER MODULE

SUPER MODULE 4/5 SUPER MODULE 3 PROPOSED

650 TONS 700 TONS SUPER MODULE 2/7

Fig. 15. The proposed "super" megamodules for CPF-12, HMCS Ottawa

Fig. 14. HMCS CharlottetownKeel-laying

References

[1] D.J.S. Beck, "The Applicationof Advanced Design andConstruction Techniques to theCanadian Patrol Frigate," present-ed to the CIMarE, April 15, 1986.

[2] Capt(N) R.E. Chiasson, "DPM(Construction) Lessons Learned,"June 15, 1990.

[3] Cdr PJ. Child, "The Acquisitionof New Ships for the CanadianNavy," presented to the SNAMEConference, Washington, DC,Summer 1985.

[4] Cdr L.P. Dumbrille, "CPF LessonsLearned," Aug. 14, 1985.

[5] R.G. Keane and H. Fireman,"Producibility in the Naval ShipDesign Process: A ProgressReport," Journal of ShipProduction, Vol. 9, No. 4, Nov.1993.

[6] Cdr P. McMillan and LCdr B.Staples, "Saint John ShipbuildingLimited and Canadian PatrolFrigate (CPF) Construction,"Maritime Engineering Journal,Jan. 1987, p. 5.

[7] LCdr R. Payne, "The ProductWork Breakdown System —Blueprint for CPF Construction,"Maritime Engineering Journal,Sept. 1988, p. 17.

[8] M. Reid and J.J. Dougherty, "TheFirst Time Integration of Productby Stage of Construction withCost/Schedule ControlApplication," presented to theShip Production Symposium,Arlington, Va, Sept. 13-15, 1989.

[9] LCdr A. Smith, "Product OrientedDesign and Construction Impacton Operating and Support Costs,"prepared for the ASE Seminar,Dec. 22, 1993 (Draft).

Capt(N) Blattmann was the CPF DetachmentCommander in Saint John, N.B.from 1990until his appointment as CO of Ship RepairUnit Pacific in 1994.

Cdr Archibald was the Leadyard Commanderof the naval staff at the Saint JohnShipbuilding Limited yard from 1993 untilhis appointment as the CPF DetachmentCommander in 1994.

12 MARITIME ENGINEERING JOURNAL. JUNE 1995

Incident at Sea:Oxygen System Explosion inHMCS CormorantArticle by LCdr Jim Muzzerall, Stephen Dauphinee and LCdr Kevin Woodhouse

On Nov. 18, 1992 the navy's divingsupport ship HMCS Cormorant was con-ducting local operations off Nova Scotiawhen the ship suffered a small explosionin her diving-gas flask stowage compart-ment. The ship had just completed div-ing operations with the submersibleSDL-1, and was preparing to refill thesubmersible's oxygen tanks when theexplosion occurred. Refilling tanks isa normal post-dive procedure, but thiswas the first such oxygen transfer tobe made since Cormorant's refit sixmonths earlier.

The flask stowage compartmentcontains 28 oxygen flasks and 20 helium-oxygen flasks, storing diving gases at1,650 psi. The gases are used by the div-ers, the two submersibles (SDL-1 andPisces) and the ship's recompressionchamber. The diving gases and com-pressed air are delivered throughout theship via the manifolds and piping of thediving-gas distribution system.

As personnel prepared to refill SDL-1'soxygen tanks to 3,000 psi, the necessaryvalves were opened to pressurize thegas-transfer booster pump. This wouldallow oxygen stored at 1,650 psi in theflask stowage compartment on 2 deck topressurize the line up to the inlet of thegas transfer booster pump located out-side the compartment. The pump outletwas to be connected to the SDL-l's oxy-gen tanks, but one valve was inadver-tently left closed. As the booster pumpincreased the oxygen pressure from1,650 psi to 3,000 psi, an explosionoccurred inside the flask stowagecompartment.

Fortunately, the personnel conductingthe oxygen charging were at the boosterpump just outside the compartment.They heard a loud bang, but thought itwas the relief valve lifting. (The reliefvalve was set only 50 psi above 3,000.)They shut the pump down and upon see-ing thick, grey, rusty smoke quickly

raised the alarm. The Rapid ResponseTeam arrived and manually activatedthe halon extinguishing system. Whenthe attack team finally advanced intothe flask stowage compartment, theydiscovered the fire out and the bulk-heads and deckheads scorched (Fig. 1).

At first the scope of the reported fireincident and the potential hazard to per-sonnel and equipment were not recog-nized. On arrival in Halifax, Cormorantwas met by SRUA pipe fitters ready toremove damaged parts, NEUA specwriters trying to assess the scope of therepair job and squadron technical stafflooking for a first-hand damage assess-ment. It was then that squadron staffrealized the fire incident was in fact anexplosion resulting from a catastrophicfailure of a component of the oxygensystem. The area was immediately qua-rantined. No repairs would commenceuntil a technical investigation had beencarried out.

HMCS Cormorant


Fig. 1. The fire-damaged flask stowage compartment on board the diving-support ship HMCS Cormorant.

The technical investigation discov-ered an exploded relief valve and aburned transfer hose (Fig. 2). A quickinspection of an undamaged transferhose in the system revealed a poly vinylchloride dust plug (Fig. 3) that shouldhave been removed prior to installation.The possibility that a similar plug hadalso been left in the damaged hoseseemed likely. In addition, an excessiveamount of silicone grease was found inthe oxygen bank manifold unions. Sincethe presence of such contaminationimplied negligence, or possibly sabo-tage, the technical investigation was ter-minated with a recommendation that asummary investigation be conducted.The summary investigation wouldattempt to determine the cause of theexplosion and whether or not grossnegligence played a part. It wouldalso recommend measures to preventrecurrence.

Summary Investigation

The summary investigation led to thefollowing conclusions:

• The diving-gas system had beenneither certified clean, nor func-tionally tested;

• Certain system valves and unionshad been extensively lubricatedwith silicone — a substanceknown to act as a fuel in an oxy-gen enriched atmosphere;1 and,

• A PVC dust plug had been inad-vertently left in a stainless steeltransfer hose. Such a plug in apressurized oxygen line can actboth as an obstruction and as afuel.2

The silicone contamination was apossible cause of the explosion. Siliconegrease found in the system "is more like-ly to ignite and will release more heatthan fluorinated greases once ignited."3

The PVC plug found in the system

pointed to another likely cause of theexplosion. "Presence of a similar plug inthe transfer hose (which was) destroyedcould have provided the fuel necessaryfor the fire to start and destroy the reliefvalve and transfer line."4 Except for pro-cedural error, the closed valve did notchange the outcome of the charging. Itonly made the relief valve lift sooner.The investigation concluded that theexplosion in the oxygen transfer systemwas probably caused by maintenance-induced contamination (i.e. the PVCplug or the silicone grease) acting as thefuel, with oxygen as the oxidizer andhigh-pressure oxygen under adiabaticcompression as the ignition source.

As a review, adiabatic compressionoccurs when high-pressure gas is rapidlyintroduced into a low-pressure systemand strikes a barrier. The increase inpressure causes a dramatic increase intemperature. Theoretically, oxygen underadiabatic compression caused by 3,000psi entering a system at one atmosphereand 20°C, will reach a temperature of1,066°C. PVC in pure oxygen at oneatmosphere ignites at about 390°C.5Clearly, the theoretical temperaturecaused by adiabatic compression wellexceeded the PVC dust plug's ignitiontemperature.

When the contaminated oxygensystem was pressurized the relief valvelifted, allowing 3,000-psi gas to strikethe PVC plug. It was only a matter of aninstant before the adiabatic compression

Fig. 2. The damaged relief valve and transfer hose in the flask stowagecompartment.

14 MARITIME ENGINEERING JOURNAL, JUNE 1995

of oxygen raised the temperaturesufficiently to ignite the PVC plug.Once started, the fire drew on the sup-ply of pure oxygen and like a cuttingtorch burned through the stainless steeltransfer hose (Fig. 4) using the stainlesssteel itself as a fuel. The fire continuedto burn in the body of the open reliefvalve, weakening the valve body, result-ing in mechanical failure and subse-quent explosion. This sprayed slagand scorched the surface of bulkheads,deckheads, gas-transfer piping andassociated fittings in the flask stowagecompartment.

At some point the fire must have runout of fuel since the heat from the flameand the oxidizer were still present.(Oxygen continued to vent from theflasks until the Rapid Response Teamentered the compartment and closed theoxygen bank valves.) The fire musthave burned for perhaps only a few sec-onds. The intense heat dissipated soquickly in the compartment that it didnot activate the halon extinguishingsystem. The minimal damage indicatedthat the fire was out well before theRapid Response Team activated thehalon extinguishing system.

Why did this happen? How did thecontamination enter Cormorant's oxy-gen system? How did it go undetected?How could the diving-gas system havebeen approved for use? These weresome of the questions that led to therevelation of several oxygen systemmaintenance problems.

"•'•"-..„::. ••'••'

Fig. 3. This PVC plug was found in the undamaged transfer hose which wasnot pressurized during the explosion.

System Contamination

The PVC plug in the stainless steeltransfer hose was there because some-one forgot to remove it. New hoses fromthe manufacturer are delivered with"plugs in" to keep the hoses clean.Evidently, a PVC plug was left in andQA did not find it.

Excessive silicone grease, which isnot approved for use in oxygen systemsbecause of the fire hazard associatedwith its ignition characteristics, wasfound in some oxygen bank piping.

Fig. 4. This stainless steel transfer hose was destroyed during the explosion.Its purpose was to connect a relief valve to the oxygen pressure reliefdump line.

(The only grease approved for divingsystems is Christo-lube MCG III.6) Theunapproved grease in the diving-gassystem could have been introduced dur-ing refit or maintenance. Hence, routineship maintenance might have been acontributing factor. The investigationfound that first-line maintenance of div-ing-gas systems was being conductednot by the engineering department, butby divers who might not be aware ofcommon engineering procedures relat-ing to tests and quality assurance.

Yet, even if a diving-gas system werecontaminated during maintenance, thesystem tests and trials should haverevealed the problem. Unfortunately, asCormorant's oxygen system work wasstill incomplete at the end of her refit,the tests were not conducted. A systemretrial/retest was neither observed as adeficiency in the CF 1148 Record ofInspection, nor recorded as having beenconducted. It should be noted that thefunctional test specified in the refit didnot require the relief valves to be testedin situ. As a consequence of this, the in-situ operation of these valves is provenat the first six-monthly maintenanceroutine or, as happened in this case, atthe first actual lifting of a relief valve.

In the final analysis it is unclear whowas responsible for the PVC or siliconecontaminants. What is clear is thatinsufficient quality assurance played arole, whether on the part of the contrac-tor, CFTSD, SRUA or ship staff. Theproduction of unclear maintenance and


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repair deliverables also played a part.The existence of these deficiencies wasan indication of the naval engineeringcommunity's lack of appreciation of thehazards associated with oxygen systems.

Repairs

A month after the explosion, oncompletion of the summary investiga-tion, a 30-page job instruction (whichclosely resembled the original refitinstruction) was prepared by NEUA.SRUA would be tasked with the repairwork, while Cormorant divers wouldprovide the QA function.

The basic valve and pipe repair andoverhaul procedure would involve:

• removing the valves for cleaning;

• flushing the piping with jumpers atvalve locations;

• reassembling the valves tothe piping;

• conducting pressure tests;

• taking a gas sample; and

• functionally testing the system.

Once removed from the piping thevalves were disassembled to separatemetal and plastic components. The metalcomponents were cleaned with Freon inan ultrasonic bath, then all componentswere washed with a surgical detergent

and rinsed in water. The parts wereinspected under black light to ensure nohydrocarbons existed, then were reas-sembled and pressure tested with eitherpure nitrogen or helium. Finally, endcaps were installed, the valves weresealed in heavy plastic bags and certifi-cation tags were attached. The valveswere then returned to the ship forinstallation.

On board the ship the pipes of thediving-gas system were flushed withcirculating Freon for 30 minutes, thenreflushed for 15 minutes with a freshsupply of Freon. A sample of the Freonwas then collected in a petri dish andtaken to a Clean Room where it wasinspected for hydrocarbons under a blacklight. The Freon was then evaporated sothe petri dish could be inspected visuallyfor residue under a black light. Once cer-tified clean, the pipe circuit was purgedof Freon using hot nitrogen gas, afterwhich the pipe ends were capped andcovered with heavy plastic and a certifi-cation tag was attached.

The newly cleaned system compo-nents were reinstalled and pressuretested for strength and tightness(i.e. leakage). The pressure test wasuneventful except for the helium test onsome flexible hoses which allowed somehelium gas molecules to effuse throughthe Teflon hose material. Although the

hoses all passed the strength test, certainones could not pass the tightness test.Spare hoses fared no better, but weregranted temporary waivers to allow thesystem to be used until full-spec replace-ment hoses could be installed (fivemonths later).

The final part of the repair processinvolved sending a gas sample to MannLabs in Toronto for analysis. On thestrength of the results, DCIEM certifiedthe gas safe for diving. The ship's staffreviewed the SRU documentation forcompleteness and everything was a gofor a dive. Off they went at the end ofMay 1993. A few days later we got amessage to say the function test wassuccessful, nothing blew up and the airtasted great.

Problems

The repair process was not withoutits obstacles. To begin with, the Freonproved ineffective in removing the sili-cone contamination. Thus, the valveshad to be chemically cleaned and thepipes steam cleaned, which addedsignificantly to the repair time.

Second, with the silicone removed,the initial flushes still showed signs ofhydrocarbon. After much head scratch-ing it was decided that the workspacewas the major contributing factor. Itseems the system and samples were opento a wide range of potential contami-nants (Fig. 5). Although CFTOs do notspecifically say so, it made sense toestablish clean areas for conductingvalve cleaning, pipe flushing and testing.Gas system cleanliness is important bothfor providing the divers with clean airand for preventing an explosion hazard.To ensure cleanliness, a number ofCFTOs exist which describe the generalrequirements and procedures for main-taining diving-gas systems and takinggas samples. But if the gas must be pure,how clean do the valves and pipes haveto be? Essentially, very clean. Theremust be:

• no hydrocarbons;

• less than 5 ppm residue in thecleaning fluid; and

• no residue inside the components.

What is interesting is that even parti-cles that are less than 10 microns indiameter (all the invisible stuff) cancause contamination. Clearly, the DNDstandard white glove test would not begood enough to screen these out.


Accordingly, a clean work area wasestablished in the ship. The sealed offarea was fed by filtered air and main-tained at a positive pressure to repel air-borne contaminants. The Freon flushingagent and Freon samples were carefullyprotected from contamination. A CleanRoom was also set up ashore in buildingW7 in Dartmouth, containing a securework area, a work bench and a pressuretest facility. At Cormorant's suggestionthe place was cleaned like a hospitaloperating room. Access was limited byrigging plastic curtains at all entrancesand by posting No Trespassing signs.Anyone entering either of the clean areashad to wear white, lint-free coveralls.When we resumed flushing, the contami-nation disappeared.

Finally, we ran out of Freon refriger-ant during the flush. With all the con-tamination problems, SRUA had beengoing through 45-gal. drums of the stuffand Freon was in desperately short sup-ply everywhere. What to do? We couldtry using Trisodium Phosphate, but wefelt the technical risks would be toogreat. In the end we decided to recyclethe Freon. It was amazing how quicklythe Pipe Shop constructed a "DownHome" style still to evaporate the refrig-erant. We were soon back in production.

Lessons Learned

Broadly speaking, we split the lessonslearned into two categories: those specif-ic to Cormorant, and those applicable toall hyperbaric diving-gas systems. Ingeneral, the single-most important lessonstemming from this incident was theneed for a knowledgeable user-maintain-er (one of Cormorant's ship's staff) to bededicated to the refit work on the ship'sdiving-gas system. After all, someonewhose life will later depend on thesystem will likely focus intently on allaspects of safety and security.

Due to the inherent dangers associat-ed with high-pressure oxygen reliefvalves, we recommended that heavysteel shielding be installed around thevalves to minimize injury or damage incase of an explosion. We also recom-mended that some method for isolatingthe gas supply from the flasks be fittedoutside the compartment. During theincident the crew had to enter the com-partment to do this. The relief valvelift pressure also came under scrutiny.Having it set only 50 psi above the

3,000 psi maximum was obviously muchtoo close for comfort, especially sincethe compressor pressure cutout switchoperated above this setting. The oxygenrelief valve was reset to lift at operatingpressure plus 10 percent — 3,300 psi.So now, not only will the compressor cutout well before the relief valve is set tolift, but the valve will only lift if thecompressor does not cut out.

The explosion and damage, the resultof a routine operation, forced a reexam-ination of diving-gas system mainte-nance procedures used by the Canadiannavy. The repairs to Cormorant's diving-gas system were successful, thanks ingreat part to the fact that a single agency— SRUA — was responsible for allaspects of the repair and certification.They disassembled the system, cleanedthe valves, cleaned the pipes, reassem-bled the system, took air samples andcertified the system clean. Many prob-lems occurred during the rebuild, butthese were resolved by the combinedefforts of SRUA, Cormorant staff,squadron staff, the EnvironmentalDiving Unit in Toronto and NEUA.

How long did all of this take? Thetotal down-time was six months. Onemonth was taken up by the technical andsummary investigations. If the repairshad been confined to explosion damageonly, the time to repair would have beenapproximately VA months. The extensivesilicone contamination added aboutyA months to the repair.

Why this interest in diving systems?Well, to begin with, SCUBA chargingsystems are found in all ships and sub-marines. And contrary to popular belief,it is the engineer officer who is respon-sible for the maintenance of these div-ing-gas charging systems — not thedivers. You could find yourself posted toa Fleet Diving Unit where your majorresponsibility would lie, not with themain engines in diving tenders, but withdiving-gas system problems. So if noth-ing else, remember that cleanliness iscritical to the success of a diving-gassystem.

Acknowledgment

The Cormorant diving-gas incidentpresented some fairly specific require-ments in terms of maintenance andrepair procedures. We figured we couldhandle the engineering side of things,

but we needed someone who could pro-vide the practical knowledge gainedthrough hands-on experience. What weneeded was a diver who had done every-thing according to the rules. In fact, wefound two — LCdr Paul Morson of theExperimental Diving Unit in Torontoand Lt.Cdr. Jack Copes, USN, whohad recently joined Cormorant. The co-operation and expert assistance of thesetwo officers was fundamental to achiev-ing the repair, and for that we thank them. 4

References

[1] "Manual on Fire Hazards inOxygen-Enriched Atmospheres,"NFPA 53M, National FireProtection Association, Inc., 1Batterymarch Park, Quincy, MA,1990, Table 5-4.

[2] NFPA 53M, Table 5-2.

[3] Defence Research EstablishmentAtlantic/Dockyard Laboratory3715 PR1AL-3-1.994, Dec. 7,1992.

[4] DREA/DL3715 PR1AL-3-1.973,Dec. 4, 1992.

[5] NFPA 53M, Table 5-2.

[6] Diving General Memorandum2/92/E DMOPR 2107 211207Jan 92.

[7] American Society for Testing andMaterials G93-88.

LCdr Muzzerall (left) is the Group AssistantTechnical Officer for CMOG1 in Halifax.He conducted the summary investigation todetermine the cause of the oxygen systemexplosion on board HMCS Cormorant.

Stephen Dauphinee (centre) is a designengineer with Naval Engineering UnitAtlantic. He directed the repair effort onboard Cormorant.

LCdr Woodhouse (right) is the GroupTechnical Officer for CMOG5. He conductedthe technical investigation surrounding theCormorant oxygen system explosion.

MARITIME ENGINEERING JOURNAL. JUNE 1995 17

Survey says!The results from our October 1994 readershipsurvey are in. Can we talk?Article by Brian McCullough

"More combat systems!"

"Down with combat systems!More marine systems content!"

"Too technical!"

"Not professional enough!"

Ever get the feeling you're in the mid-dle of a bunfight? When the returns startedcoming in from last October's readershipsurvey our first inclination was to run forcover. Especially when the high-tech guyson the next floor up from our officesstarted faxing their returns to us. Happily,we survived the experience to tell about it.

To begin with, we were thrilled withthe response. We heard from a good sam-pling of our readership and receivedenough bouquets and buckshot to keep usbusy for a long time to come. Our respon-dents sometimes let their school coloursshow, but they did manage to agree in afew important areas. We found that peoplefor the most part were satisfied with theirMaritime Engineering Journal, but wereready to blow safety valves over our inef-fective distribution.

Of the 1,550 copies of the Journalwe mailed out, 303 people took time toanswer our questionnaire. Of these,53 (mostly junior ranks) submitted "nilreturns" that made no comment other thanto say they had never heard of the maga-zine (duly noted). Two others (a leadingseaman and a lieutenant) expressed them-selves with less than Neanderthal wit intheir demands for the immediate demise ofthe Journal on money-saving grounds(also noted), but otherwise had nothingconstructive to say.

Therefore, to ensure a more accuratesurvey and in fairness to those who wereable to make informed responses, webased the rest of our findings on theremaining 248 returns — still an impres-sive 16-percent response. (During our1987 survey we received 93 replies —a seven-percent return — from the 1,400copies we mailed out.) Based on what peo-ple told us in this survey, a conservative

estimate places the total readership of theMaritime Engineering Journal at about3,100 people — that is two readers forevery copy we mail out.

Survey Who's Who

Our respondents reported in from basesand headquarters (58%), training centres(16%) and dockyards and ships (15%).The majority of the rest hailed from othergovernment departments and projectoffices. Sixty-two percent of those whoparticipated in our survey were military,three-quarters of them being MSB andCSE lieutenants and lieutenant-command-ers. There was also a solid 23% representa-tion from our senior non-commissionedmembers (NCMs), virtually all of whomwere POls or PO2s in the engineeringtechnical occupations. Of the 38% ofrespondents who were civilian, we iden-tified engineers (25%), technologists(18%) and a smattering of QA managers,financial managers, project officers,administration support officers and clerks.

On the language front, 87% of ourrespondents reported they read the Journalin English, 3% said they read it in Frenchand 7% said they read it in both languages(in some cases to practice their French).Just to confound us, one person whoapparently reads the magazine in Frenchchose to answer the questionnaire inEnglish. Another diabolical mind took theopposite tack — claimed to be an Englishreader, yet answered the survey in Frenchand in the same breath professed no abilityto judge the quality of the French content!Hmm. (Of the 41 people who did rate thetranslation, 14 pegged it as Very Good,26 as Good and one as Poor.)

Magazine Content

Readership interest across all sectionsof the Journal was encouraging, with anyone section being read on average by 67%of readers. An amazing 52% reported read-ing the magazine from cover to cover(with another 12% saying they read every-thing except for one article or column).

As far as favourite sections went, nearlyhalf the respondents said they preferred thearticles (no favourite subject emerged),21% liked the News Briefs best, 19% mostenjoyed the Forum section and 18% pre-ferred the Looking Back feature. The othersections received approval ratings ofbetween 12% and 15%. Although mostpeople refused to identify a least favouritesection, each of our regular featuresreceived a few raspberries.

People were generally happy with thecomplexity of the articles — 70% said thearticles were just right, while the rest wereevenly split on whether they were too tech-nical or too general. Similarly, two-thirdsexpressed satisfaction over the generalinterest articles, but in this case the major-ity of the remainder considered the non-technical content to be too shallow.Respondents were more definite (83%) intelling us they liked the mix of articles ineach issue.

Readers responded to the "How oftenshould we publish?" question with every-thing from twice a month (yikes!) to never(oh, pooh). One person even suggested wepublish "as often as required." By far themost popular request was for a quarterly(34%), followed by our present threeissues a year (19%), monthly publication(13%) and six issues a year (10%). Withrespect to subscription fees, extreme cau-tion was the word of the day. Fifty-eightpercent flat out said No, but a surprising30% said Yes to fees (depending, ofcourse, on how much they were).

And if you think the Hubble SpaceTelescope had a case of bad optics, wedidn't do our own public relations anyfavours when we (that is, I) inadvertentlyomitted civilians and most of the NCMengineering occupations from the list oftarget audiences in question 11. Onemiffed respondent refused to continue thesurvey. Fair enough.

What we learned in the end is that thereis strong support out there for directing theJournal to all areas of the Canadian naval


engineering community, including thecommercial sector. We were specificallyasked to include more articles and com-mentaries written by (or, of interest to)NCMs in the naval technical trades andcivilian contractors involved with navalengineering support.

Journal Objectives

We were perplexed by the number ofpeople who asked us what the magazine'sobjectives were. We publish them in everyissue. Maybe it's a case of people notnoticing the wallpaper any more. At anyrate, sixty-eight percent of respondentssaid the objectives should remain as theyare, while 21% offered no opinion.

Several people told us the magazine istoo light on the technical side to be a pro-fessional engineering branch journal. Ourprimary concern, another said, should beto promote interest, knowledge and aware-ness. Still others suggested we broadenour outlook to include our place in indus-try and internationally. A number ofpeople said we should be gearing the pub-lication more toward the NCMs who makeup most of the branch. One engineer ques-tioned our having a senior MARE namedas editor. "As long as the stated editor is aCapt(N)," he wrote, the Journal "will notbe an open forum. Lesser ranks will feelintimidated." In a similar vein, anotherperson said we do not offer a proper forumwhere all viewpoints appear welcome —"too much party line."

Reality Check

Asking readers to rate the usefulness ofthe Journal was instructive. While 67%said they found it useful, 27% reportedthey had little or no use for it. Some peo-ple didn't like our choice of words, sayingthey considered the magazine to be moreeducational than useful. (Perhaps weshould have polled readers as to theimportance of maintaining a journal.) Asfar as overall impressions went, 17% saidthey were Very Favourably disposedtoward the Journal, 56% said Favourablyand 3% said Unfavourably. What bothersus is the 19% who gave a Neutralresponse. Put all of this in the context ofthe entire survey and it seems clear that(a) people want a more current and work-oriented journal; and (b) our hit-and-missdistribution is killing us.

So where do we go from here? Thebottom line, of course, is to make theJournal better for you the reader. Wereceived a good number of suggestions,some widely popular, others delightfullycontradictory. What impressed us most

was the depth of your interest in theMaritime Engineering Journal. Here is ataste of what you told us:

Policy & Production

• ensure regular delivery;

• institute "Article of the Year"awards to promote excellence inarticle writing;

• expand the Journal to represent allnaval MOCs;

• get more input from commercialmaritime organizations anduniversities;

• make the Journal more accessible,more fun to read;

• make the magazine more suitablefor junior ranks (eg. establish NCMtechnical editors and NCM Corner);

Format

• provide an electronic edition(e-mail and CD-ROM);

• separate the English and Frenchsections to save $$;

• emulate the Journal of NavalEngineering, Proceedings, IEEEjournals, Popular Science;

• print on recycled, recyclablematerials;

• use more colour and more photos;

• adopt a newspaper tabloid formatto save $$;

More News about...

• project updates, advancesin industry;

• engineering trends and problemareas;

• conference and seminar schedules;

• organizational changes(eg. Op Excelerate);

• branch interests (eg. NCM training,MARE OA);

• Who's Who and Who's Where inCanadian naval engineering;

Editorials/Opinion Pieces

• establish regular departments formajor engineering organizationsand MOC advisers;

• more open discussion of controver-sial issues — less pap, less process;

more Way Ahead articles by seniorofficers;

more leadership discussion;

create a question and answer column;

Articles

more professional interest(eg. case studies);

report current technical policy issues;

more ship systems and "dirty hands"type of articles;

more emphasis on engineering andproject management;

more historical technical subjects;

more CSE and software engineeringarticles;

more humour (eg. cartoons, funnyphotos, anecdotes);

publish "Notes from Sea;"

publish summaries of master'stheses;

In General...

• do nothing — it's so bad now...;

• it's great, keep it coming — don'tchange a thing;

• no more surveys!

So there you have it. Thanks to yourexcellent response the editorial committeecan now forge ahead with more informeddecisions regarding the magazine's purposeand direction. This was only the secondreadership survey in the Journal's 13-yearhistory. Our aim this time is to refocus theJournal to meet the needs of the Canadiannaval engineering community duringthis new era of more responsible fiscalmanagement.

By the time you read this we will havealready taken steps to get a handle on ourNumber One priority — the distributionproblem. There are bound to be glitches,but with your assistance and continuedgood humour we can get the machineworking smoothly again as soon as pos-sible. Thank you for your very kind wordsof encouragement and, yes, for your bitingcriticisms as well. (Perhaps one day we canreturn both.) We look forward to all yoursubmissions to the Journal.

See you around the farm. 4

Brian McCullough has been Production Editorof the Maritime Engineering Journal since 1985.


Interference Suppression using an HFAdaptive Antenna Receiving System(HFAARS)Article by Lt(N) Michael P. Craig

Introduction

Major advances in digital signalprocessing (DSP) have affected allareas of military combat systems. Theincreased throughput, reduced size andlower power consumption of DSP chipshave permitted the development of sub-systems which improve overall systemperformance. One such subsystem is theHigh Frequency Adaptive AntennaReceiving System (HFAARS).

Adaptive antenna receiving systemsare used to suppress signal interferencein radio communications. Interferencecan originate from other transmitters inthe same frequency band, man-madenoise, or from natural phenomena likethunderstorms. In the particular realm ofmilitary communications, interferencecan also take the form of enemy jam-ming signals. Adaptive antenna array

processing counteracts interference byforming a composite antenna pattern thatgreatly reduces the gain in the direction ofan interference source, while enhancingthe gain toward a desired signal (Fig. 1).

In the simplified system descriptionshown in Fig. 2, the signal from eachantenna in the array is received by inde-pendent HF receivers, digitized andpassed to a DSP for filtering, frequencyshifting and generation of complex data.The filtered data is then examined todetect the onset of the communicationssignal and to synchronize to it. Adaptiveweights are calculated to enhance theknown reference features embedded inthe communications signal and at thesame time to suppress other (interfer-ence) signals. The weights adjust thephase and amplitude of the receivedsignal from each antenna. Finally, the

ADAPTIVE ANTENNA ARRAYS

Receiving pattern altered by adjusting array weightsNulls directed toward unwanted signalsHigh-gain maintained toward:- direction of interest (direction constraint)- signal of interest (reference signal constraint)

Fig. 1. Typical scenario for adaptive antenna arrays

signals are combined to cancel the unde-sired interference signals and to obtain amaximum signal-to-interference ratio.

DND Research and Development

The AN/FRQ-26 HF receiving systembuilt by the Andrew Corporation featuresadaptive interference-cancelling tech-niques using four identical HF receiversand antennas. It can suppress up to threeindependent jammers to enhance thereception of Link 11 and FSK (frequen-cy shift keying) signals. This particularsystem (the only one of its kind knownto be in production) was purchased in1991 under an R&D project managed byDMCS 6 and sponsored and funded bythe Chief of Research and Development(CRAD).

Research into interference suppres-sion by DMCS 6 began in mid-1990with the goal of investigating and devel-oping an advanced HF adaptive antennasystem at the Communications ResearchCentre (CRC) at Shirley's Bay nearOttawa. Thus far, the signal processingtechniques and real-time software havebeen developed primarily for naval use.It has been demonstrated that the systemcan provide reliable communications inthe HF band in the presence of virtuallyany type of interference or jamming sig-nal. The processing techniques can beextended to other military and civilianapplications, such as land mobilecellular radio.

The continuing focus of the HFAARSresearch and development project hasbeen on developing DSP algorithms tocounteract intelligent jammers to max-imize HF data rates in hostile environ-ments. Work accomplished at CRC sofar has resulted in the writing of tailoredDSP algorithms for taking advantageof specific HF data protocols used infriendly communications. The aim is toautomatically detect and synchronizewith the onset of a friendly signal in ahostile communications environment in


real time. The messages are then separat-ed from the jamming signals, demodulat-ed and decoded.

Two newly developed HF protocolswere selected for the initial algorithmand software development. They are theNATO STANAG 4285 waveform andthe U.S. Mil-Std-188-110A waveform.Both are HF serial tone waveformsfor digital data transmission and aredesigned to take advantage of optionalerror-correction coding. Antijammingalgorithms developed by CRC for use inan HFAARS system contain the follow-ing basic processing procedures:

• detection of and synchronization tothe communications signal;

• suppression of interference signalsof various waveforms, includingtime-varying or pulsed jamming;

• de-interleaving data and error-correction; and

• demodulation and decoding.

Work completed to date on theHFAARS system has resulted in thecapability to enhance the reception of theSTANAG 4285 waveform in the pres-ence of various types of jamming. Mostof the research has been in the area ofsoftware algorithm development and inupgrading the digital signal processinghardware. Due to the increase in pro-cessing capability, the HFAARS systemcan automatically recognize theSTANAG 4285 waveform and rejectother interference signals without opera-tor intervention. Some of the interferencesignals which have been tested againstthe HFAARS system include: fixed tone,chirp, continuous noise and pulse noisejamming.

Adaptive antenna receiving systemrequirements for the naval environmentare particularly demanding. A systemmust be able to adapt quickly to shipmotions which tend to veer the antennapattern null away from the interference.Additional complexities in the navalenvironment are the RF harmonics andintermodulation noises generated by theship itself. The directions of the jammingsignals and shipboard noises areunknown in practice and can changequickly. These undesired signals mayalso be statistically non-stationary —i.e. behaving as impulsive noise.

The signal processing algorithmsdeveloped at CRC have been demonstrat-ed in field trials to achieve very high

DESIRED SIGNAL

DESIREDSIGNAL

SUMMEDOUTPUT

COMBINED RECEIVE OUTPUT

Fig. 2. System description — adaptive antenna array processing

signal detection rates and very low bit-error rates in the presence of the mostsevere types of interference (i.e. jam-ming-to-signal ratios exceeding 30 dB).Of the various types of jamming, pulsenoise jamming is considered to be oneof the most severe and difficult todefeat.

HFAARS's four HF receivers arewell matched in phase and amplitude,which is essential for good interferencesuppression performance capability. Theheart of the system is the programmableDSP processor. This DSP chip is wherethe real-time adaptive signal processingand data processing are performed.The original HFAARS hardware fromAndrew contained transputers for thesignal processing, but these have beenreplaced by a single Texas InstrumentsTMS320C40 (C40 for short) digital sig-nal processor. Although the STANAG4285 algorithms require only one C40,future algorithms requiring more pro-cessing power can be accommodated bysimply adding more C40 chips.

Techval S/859 HMCS Saskatchewan

By the end of 1993 research on theHFAARS system had progressed to apoint where a shipboard technical evalu-ation (techval) became necessary. Theevaluation would validate the work doneby CRC and determine further develop-ment needed to transform the systeminto an end product. In February 1994 aweek-long HFAARS techval (S/859)was conducted on board HMCSSaskatchewan. The techval took placealongside and at sea in the Gulf Islandsand Georgia Strait. Assistance came

from HMCS Restigouche, acting asan enemy jamming ship, and CFSAldergrove (Matsqui) which transmittedthe source message signals.

The techval showed conclusively thatthe HFAARS running the STANAG4285 waveform antijam algorithm canperform effectively in a hostile opera-tional environment using existing ship'santennas. It also demonstrated that theFSK antijam algorithm provides signifi-cant benefit against a jamming signal. Itshould be noted that this was the firsttime Aldergrove transmitted messages ata data rate of 2400 baud to an operation-al unit at sea. The use of serial tonewaveforms (i.e. RF-5710 modem capa-bilities) in conjunction with HFAARSwill greatly increase the reliability andthroughput of message traffic at sea.

The Future of HFAARS

Further development work willincrease the capabilities of HFAARS byproducing new software algorithmswhich include updating FSK and Link11 antijamming capabilities, as well asenhancing the reception of the new Mil-Std-188-110A waveform. Improvementsto the reception of HF signals via sky-wave transmission paths, with their asso-ciated Doppler spread and multipathdelay distortions, are also planned.

The algorithms and software are cur-rently designed to run on the AndrewCorporation's AN/FRQ-26 HF AdaptiveAntenna Receiving System. Althoughthe AN/FRQ-26 is used at CRC as atest bed to validate the performance ofthe signal processing algorithms and


software in a laboratory setting, it is fair-ly large for its function and uses olderDSP technology (transputers). Clearly, anew hardware architecture will beneeded to run the software algorithms.Since the new software is written in "C"it is logical to make the minor modifica-tions necessary to transport it to othersimilar signal processing platforms.

Thus, with the advent of new elec-tronic technology, future versions of theadaptive antenna receiving system willbe much smaller and cost significantlyless. The envisioned host architecture forthe C40 DSP chips containing the anti-jamming algorithms is the new VXI(VME Extension for Instrumentation)standard which is an RF version of theVME bus architecture. HE receiver

modules, DSP modules containing C40chips and 486-based computer control-lers, all of which are VXI compatible,are commercially available today. Devel-opment work would require the softwareintegration of these modules and imple-mentation of the adaptive receivingalgorithms.

A contract has recently been awardedto SED Systems of Saskatoon to build aprototype HFAARS system (which willbe based on the VXI architecture). Thecontract is expected to be completed inearly 1996, followed by up to six monthsof operational evaluations of the newprototype, including feedback from theusers. It is then planned to purchase pro-duction units for each major war vessel.It is possible the adaptive antenna

receiving system will eventuallyevolve into a multichannel, multiband,multifunctional, fully programmableradio system. Such a system would satis-fy most naval communications require-ments for peacetime and wartime wellinto the next century. 4

Lt(N) Craig is the R&D officer for DMCS 6.

Greenspace: M

Hydrogen Sulphide GasA Deadly ShipmateArticle by Lt(N) K.W. Norton

Most naval engineers are familiar withthe dangers posed by confined spaces.However, a new threat has emerged withthe advent of national and internationalpollution prevention regulations.Changes in operating procedures andthe installation of black, grey and oilywastewater systems in response to theserequirements have increased the tenden-cy for the onboard generation of toxichydrogen sulphide (H2S) gas.

Although a "rotten egg" smell is read-ily associated with low levels of hydro-gen sulphide gas, few people are awareof the dangers it presents. Fatalities dueto H2S gas inhalation have been docu-mented by the USN and RAN, as well asby civilian agencies. A recent accident inthe maintenance support ship HMASStalwart, involving H2S gas generated inan oily water sullage tank, resulted in thedeath by asphyxiation of three sailorsand the hospitalization of 56 others.

Hydrogen sulphide is an asphyxiantgas generated when iron sulphide reacts

with dilute sulphuric or hydrochloricacid. It is also formed when sulphate-reducing bacteria (SRB) anaerobicallymetabolise the sulphur components oforganic matter such as petroleum prod-ucts, detergents, sewage, food debrisand treatment chemicals. This anaerobiccondition can occur at the interfacebetween water and organic matter inconditions as diverse as oil, fuel andsewage. Although SRB are common inthe marine environment, and thus in thebilges of ships, growth of these bacteriain significant quantities occurs onlywhen several important factors aremet simultaneously:

a. Since sulphate-reducing bacteriagrow only in an anaerobic envi-ronment, the absence of oxygen isessential. In an environment richin biodegradable organic matterthis can be readily and rapidlyachieved by the growth of aerobicbacteria that consume the oxygen.

b. An adequate source of sulphate(or other reducing form of sulphur)is also required for SRB growth.Since sulphate is a significantcomponent of the salts in seawater, sulphate is usually presentin significant quantities in bilgewater and gravity blackwatersystems. It should be noted, how-ever, that the upper limit of theH2S hazard will be governed bythe amount of usable sulphur thatis present.

c. Growth of SRB and other bacteriain waste water also requires thepresence of an oxidizable carbonsource. This is required to produceenergy for the bacteria and forgrowth of cellular matter. Biode-gradable detergents present in bothbilge and blackwater systems cansatisfy this need either directly orindirectly through partial break-down by other bacteria in the waste.


0.05 ppm

0.10 ppm

10 ppm

30 ppm

50 ppm

DA

NG

ER

ZO

NE

150 ppm

300 ppm

500 ppm

600 to1000 ppm

4300+ ppm

detectable by odour

irritation of eye and upper respiratory tract

threshold limit value (8 hrs exposure)

very strong smell but not unbearable

casualty complains of painful eye irritation, a halo aroundlights, headache, loss of sense of smell, nausea, rawnessin throat, cough and respiratory difficulties

rapid olfactory fatigue occurs (loss of sense of smell)

unconsciousness after a few minutes' exposure

rapid onset of unconsciousness after a few breaths,respiratory centre stimulation and rapid breathing

single breath causes immediate respiratory arrest andunconsciousness

explosive range — ignition temp. 500°F

Table 1: Effects of Varying Concentrations of Hydrogen Sulphide Gas

d. Other minor components, includ-ing phosphate, trace minerals andvitamins are also essential for bac-teria growth. These can enter bilgeand blackwater systems throughaddition of chemical formulationssuch as cleaning agents and deter-gents and by the discarding of foodscraps and rubbish.

A lag time of several days is generallyrequired before hydrogen sulphidebegins to generate, after which the rateof H2S production increases rapidly.The time to achieve an anaerobic state(and subsequent increased risk of H2Sgeneration) is accelerated under highertemperature conditions, with most SRBmicrobial activity favouring an ambienttemperature range of 20 to 40°C. As theSRB multiply, a microbial film (sludge)accumulates on the surface. This createsan increasingly anaerobic environmentconsistent with the consumption ofoxygen by aerobic bacteria, even if thebulk of the mixture is oxygenated. Thisanaerobic decay can occur at any inter-face between water and organic matter.

Oily and blackwater wastes are nowroutinely stored on ships for periods wellin excess of the lag time. Additionally,conditions ideal for SRB growth exist inbilges, black/greywater tanks and oilywater collection and storage tanks. Thehazard of gas being released by disturb-ing the sludge blanket in these spaces isnot widely appreciated.

Hydrogen sulphide gas is heavier thanair and can reach high concentrationsin poorly ventilated areas. Although H2Sis not toxic at low concentrations(< 10 ppm) it has a characteristic pun-gent rotten egg odour at these low levelsthat seriously degrades the quality of theworking environment. Unfortunately,odour is not a good guide to the presenceof toxic levels of H2S in the air. As thedata in Table 1 shows, hydrogen sul-phide cannot be detected by smell (as aresult of olfactory paralysis) at concen-trations where it presents a severe toxichazard to personnel. The olfactorynerves rapidly become fatigued anddesensitized at moderate concentrations.In environments where H2S is known toreach high concentrations, or where acci-dents involving hydrogen sulphideasphyxiation have occurred, the presenceof this smell in the air should not be dis-missed lightly. Such conditions shouldbe investigated with appropriate moni-toring equipment to determine the extentof the hazard.

Minimizing the generation of hydro-gen sulphide in shipboard waste is essen-tially a "housekeeping" problem, bestsolved by prevention. The generation ofH2S will be retarded if the wastewaterenvironment can be prevented from sup-porting the growth of sulphate-reducingbacteria. The best treatment for minimiz-ing H2S generation in the bilges is tokeep them clean, using only approved

cleaning agents. Most detergents containthe nutrients necessary for SRB growth.More importantly, oily wastewatershould not be stored any longer thannecessary, especially in warm climates.

The bilges, of course, are just onelocation where hydrogen sulphide gascan form. It can also be generated in bal-last tanks and in fuel and lubricating oilsystems. An incident has even beenreported of hydrogen sulphide beinggenerated in the crankcase of a dieselengine. Wastewater tanks are very sus-ceptible, the conditions there being idealfor sludge blanket formation. It is abso-lutely essential that preventive mainte-nance instructions governing thewashing down and emptying of thesetanks be strictly observed.

Sound judgment and intimate knowl-edge of the hazards associated withhydrogen sulphide gas are necessary ifdangerous situations are to be avoided.Good housekeeping, established routinesfor entering spaces with non-Chemoxbreathing apparatus, and use of a gasdetector such as the Exotox-50 will offeran adequate level of safety. £

References

[1] RAdm R.R. Calder, RAN,Understanding the Dangers andCausation of Hydrogen Sulphide,CNE 1281/85, Dec. 12, 1985.

[2] Cdr M.H. Hall, RAN, Toxic GasAccident in HMAS Stalwart,DTSN 27/86, March 19, 1986.

[3] C-03-005-033/AA-000, NEMVol. I, Part 4, Sect. 1, ch. 3.

[4] Dr. K.C. Hodgeman, et. al.,Hydrogen Sulphide Generation inShipboard Oily-Water Waste,Appendix C to IEP/ABCA/3Proceedings, 1991.

[5] Something Nasty in the CrankCase, Marine EngineeringNewsletter, Sept. 1994.

Lt(N) Norton is the DMEE 5 project engineerfor liquid waste systems.


HMCS Eraser — Last of the ISLsWhen she paid off on Oct. 5, 1994, Fraser became the last ofCanada's "original seven" St. Laurent-class anti-submarine escortsto be retired from service. Thanks to a heritage group, the venerableship could find new life as a floating exhibit in Kingston.

Article by Brian McCullough

The times they are a'changing, and soare the ships. The Canadian navy closedan important chapter in its history lastOctober when HMCS Fraser, the last ofthe St. Laurent-class ASW escorts, wasdecommissioned for the final time after37 years of service. Named for Canadianrivers, the 2,400-tonne Fraser (DDH-233) and her six sisters, St. Laurent(205), Saguenay (206), Skeena (207),Ottawa (229), Margaree (230) andAssiniboine (234), were the first majorwarships to be designed and built inCanada.

When they were commissioned intothe Royal Canadian Navy in the mid-1950s the St. Laurents were regarded asthe state of the art in ASW surface-shiptechnology. Their unique combination ofavailable speed, Canadian-designedsonars and effective ASW armament(mortars and torpedoes) put them in aclass of their own. With their gas-tight,positive-pressure citadel and distinctiverounded hull the ships were designed tosurvive and operate in a nuclear or bio-logical warfare environment.

During the early sixties the ships wereconverted to carry a Sea King helicopterand variable-depth sonar, vastly increas-ing their effectiveness in the ASW role.Redesignated Improved St. Laurent (ISL)DDHs, the ships became operationalproof of Canada's hugely successful pio-neering work in teaming up small shipswith large ASW helicopters.

Although HMCS St. Laurent wasdeclared surplus in 1974, the rest of theclass went on to give decades of service.

In this photo of HMCS St. Laurent, probably taken in 1956, note the twinmounts of triple-barrelled Limbo ASW mortars lying horizontally in theirsecured/loading positions in the well aft, and the absence of fibreglass gunhouses on the forward and after gun mountings.


In the early 1980s the ships receivedDelex life-extension refits to bridge thegap until the Halifax-class patrol frigatescould join the fleet. As the CPFs arrived,one by one the ISLs were paid off.

Today, Fraser is the last intact exam-ple of her kind. With the exception ofSaguenay, which was stripped of her fit-tings and sunk as an artificial reef nearLunenburg, N.S. early last year, the restof the ISLs have already been, or are inthe process of being scrapped.

For Dave Matts, Greater Kingston-area director of the Canadian Naval Her-itage Foundation, it has all been a littlefrustrating. The Foundation has beentrying for years to save one of the

"cadillacs" from the wreckers andpreserve it as a heritage memorial inKingston, Ont. The group finally workedout a loan agreement to purchase Fraserfor a reported $200,000. For the moment,the ship has been "locked down" to pre-serve the artifacts. The Foundation willstill have to raise $100,000 to tow thedestroyer to Kingston.

"We're plugging away," said Matts."The sooner we get (Fraser) up here (inKingston), the sooner we can get showingher to the public and let her start carryingherself."

Life as a floating exhibit wouldmake an honourable final career for thevenerable Fraser. As the sole remaining

representative of the illustrious St.Laurent class, she would join the selectcompany of Canada's few other preservednaval historical vessels — the corvetteSackville in Halifax, the Tribal-classdestroyer Haida in Toronto and thehydrofoil Bras d'Or in Bernier, Que.As Dave Matts put it, "Fraser is the last(of the St. Laurents), which makes her allthe more important." 4

As a young naval reserve officer BrianMcCullough joined an ice-bound HMCSMargaree in Montreal for two weeks offamiliarization training in the spring of1976 —just long enough to get "TSQ'd"the hard way when a brutal 48-hourinfluenza swept through the ship's company.

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HMCS Fraser (233) with Margaree a year or two after their mid-sixties conversion to DDHs. When these St. Laurent-classescorts were built in the 1950s they represented the state of the art in ASW surface-ship technology.

MARITIME ENGINEERING JOURNAL. JUNE 1995 25

Updated design for DCsplinter boxes

An improved system of damagecontrol splinter boxes will soon be avail-able to Canadian warships. The glass-reinforced plastic (GRP) splinter boxeswill be built to a design developed inCanada from a Royal Navy concept.

Warship DC teams use splinter boxesto cover projectile and shrapnel holes ina vessel's hull, decks and bulkheads tominimize compartment flooding. Thesteel splinter boxes currently in use inthe Canadian navy are square withsides 305 mm to 457 mm long and150 mm high, and weigh between15 kg and 29 kg.

As the Royal Navy found with similarunits during the Falklands War, steelsplinter boxes are heavy and difficult tohandle, especially when water-filled inrough seas. Because of this experience,the RN went on to develop lighter GRPsplinter boxes, taking advantage of thematerial's excellent strength-to-weightratio.

A prototype unit based on the RNconcept was fabricated and tested atCanadian Forces Naval EngineeringSchool Esquimalt CFNES(E). Initialevaluation indicated that, though not

Fig. 1. This new system of glass-reinforced plastic splinter boxes features manyimprovements over the steel units presently used in shipboard damagecontrol.

ideal, the concept was an improvementover the existing steel design. The NavalEngineering Test Establishment (NETE)in LaSalle, Que. was tasked by DMEE 4to refine the design by evaluating theprototype design and incorporating otherknown desirable features.

A preliminary design for an improvedsplinter box system was developed and

the first prototypes were fabri-cated and tested at NETE.Full-scale operational testswere performed at theDamage Control divisions ofCFNES(E) and CFNESHalifax. As a result of thetesting, further refinementswere made and the final splin-ter box system design incor-porated most of the featuresdesired by DMEE 4, CFNESDC staff and NETE.

Fig. 2. A 350-mm GRP splinter box undergoingevaluation at the Damage Control divisionof CFNES Esquimalt.

The final system configura-tion comprises four sizes ofsplinter box and two securingsystems (Fig. 1). The splinterboxes range in size from

250 mm to 550 mm in diameter, weighbetween 3 kg and 8.5 kg and are stowedas two nested pairs. They are fitted withrecessed handles, feature non-slip sur-faces and have deep, flexible seal ele-ments which are easily replaced.

Depending on the situation, the boxescan be secured using traditional woodenshoring (Fig. 2), or one of the othersecuring systems for which the splinterboxes are configured. The first, a togglebolt assembly, consists of a pivotingstrongback, bolt and wing-nut. The sec-ond, a securing strap, consists of aquick-ratchet cargo strap fitted with non-slip wire hook-ends.

The new, lighter system has proven tobe easy to handle and quick to install.The system is adaptable and, in manysituations, the splinter boxes can beinstalled by one person. The new GRPsplinter box system is expected to beavailable in the fleet in early 1996.— Colin Smith, Project Officer,MSI Section, NETE, and LCdrA.J. Lafreniere, DMEE 4-2. i


CAE AwardSLt Dan Riis (DMES 6) receives theCAE Award for academic excellencein Marine Systems Engineering fromBill Grayson, CAE Ottawa's directorof business relations. (Photo byLt Chuck Doma)

The Engineer and thePrincessHRH Princess Diana was escortedduring the June 1994 unveilingceremony at the Canadian Memorialin London by a Canadian MaritimeEngineer. LCdr Ted Dochau, an MSEwith DSE 9 at NDHQ, spent fourmonths in England as special assist-ant to Capt(N) E. Davie, Naval Adviserat CDLS(L), co-ordinating CanadianD-Day activities in England.


Merit awardsCongratulations go out to the follow-

ing people who have been recognized byCanada, the Chief of the Defence Staff,ADM(Mat) or DGMEPM for their vari-ous outstanding efforts:

John Porter and Danny Morehouseof DREA for their work with DougNickerson of NEUA in isolating thecause of premature turboblower fail-ures and formulating a plan to rectifythe problem.

James Moores of DREP for hisoutstanding performance in solvingcorrosion-related problems innaval ships.

Kevin Chadwick of DMCS 4 for20 years of outstanding performance inthe fields of radar systems and navalcommand and control; particularly forhis work in resolving technical prob-lems with the AN/SPS-503 radar.

LCdr Jamie Quathamer of DMES 6for his superb achievements as theDeputy Project Director of the NavalMaintenance ManagementInformation System Project.

Lt(N) Rene Hatem of DSE 2 for hisoutstanding work as Ship DisposalOfficer.

LCdr Dave Ashling of DSE 3 for hiswork as the NDHQ project officer forthe HMCS Protecteur West Coastrefit.

Bob Laidley of DMEE 6 for his out-standing work in the area of electro-chemical power sources and AIPtechnology.

Bob Coren of DMEE 4 for his out-standing work as the LCMM respon-sible for diving and hyperbaricsystems.

Cdr Peter MacGillivray (retiredfrom DMEE 7) for his superiorachievements in organizing the 10thShip Control Systems Symposium;also noted for their outstanding workon this event were the military andcivilian members of the 10th SCSSorganizing committee and alsoMelanie MacGillivray for her "gra-cious presence, remarkable skill andenergy" in hosting the spouse program.

Military Merit

Cdr Richard Houseman of DSE(who as Naval Architecture Officer atNEUP prepared HMCS Restigouchefor Op Friction) — appointed Officerof the Order of Military Merit.

CPO2 Wayne Mclsaac of PMOMCDV (founding member of theNaval Electrical Society) —appointed Member of the Orderof Military Merit, a,

TRUMP VLS InstallationComing up in October


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