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National DefenseDefence nationale

MaritimeEngineeringJournal

September 1988

Canada

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Halifax Float-up19 May, 1988

Story and more photos on page 21

MARITIME ENGINEERING JOURNAL

MaritimeEngineeringJournal

Director-GeneralMaritime Engineering andMaintenanceCommodore W.J. Broughton

EditorCapt(N) Dent Harrison. DMEE

Technical EditorsLCdr P.J. Lenk (Combat Smews)Cdr Roger Cyr (Combat Systems)LCdr M. Bouchard (Marine Systems)LCdr Richard B. Houseman(Naval Architecture)

Production EditorLCdr(R) Brian McCullough

Graphic DesignIvor Pontiroli DDDS 7-2

Word Processing by DMAS/WPRC 4MSMrs. Terry Brown, Supervisor

SEPTEMBER 1988

DEPARTMENTS

Editor's Notes 2

Letters 3

Commodore's Corner 4

FEATURES

The Diesel Inspection Programby LCdr Richard Sylvestre 5

ASW Frigate Electrical Propulsion -The Way Aheadby W.A. Reinhardt and J.R. Storey 8

The Product Work Breakdown System —Blueprint for CPF Constructionby LCdr Richard Payne 17

New Frigates a Shipbuilding Success Storyby LCdr(R) Brian McCullough 21

Software and the MAREby Cdr Roger Cyr 22

LOOKING BACK 26

NEWS BRIEFS . . 2 8

OUR COVERJohn Henderson of the U.S.-based AmericanManagement Systems looks on as FMG(P)Diesel Inspector. CP01 Bruce Ferric inspectsa diesel engine on board the harbourtraining ship Columbia.

The Maritime Engineering Journal (ISSN 0713-0058) is an authorized, unofficial publication of the maritimeengineers of the Canadian Forces, published three times a year by the Director-General Maritime Engineeringand Maintenance. Views expressed are those of the writers and do not necessarily reflect official opinion orpolicy. Correspondence can be addressed to: The Editor. Maritime Engineering Journal, DMEE. NationalDefence Headquarters. 101 Colonel By Drive. Ottawa, Ontario, Canada Kl A OK2. The editor reserves the rightto reject or edit any editorial material, and while every effort is made to return artwork and photos in goodcondition the Journal can assume no responsibility for this. Unless otherwise stated. Journal articles may bereprinted with proper credit.

SEPTEMBER 1988 1

Editor'sNotes

It is a pleasure, this issue, to welcomethe newly appointed Director General ofMaritime Engineering and Maintenance —Commodore W.J. Broughton. By way of in-troduction, we offer this biographical sketchof our new MARE Branch Adviser.

Commodore Broughton joined the RCNin 1953 under the Regular Officer Train-ing Plan. He attended Royal Roads and theRoyal Military College, graduating in 1957,and received a BSc in mechanical engineer-ing from Queen's University in 1958. Fol-lowing basic officer training he completedpostgraduate studies in science and navalengineering at the Massachusetts Instituteof Technology. He is also a graduate of theCanadian Forces Command and StaffCollege and the National Defence College.

During the early part of his career heserved as a project officer for the FHE-400hydrofoil and was involved in structuraldesign work for the Restigouche Class(IRE) conversion. He also served in HMCDockyard, Halifax where he was responsi-ble for hull system surveys and repairspecifications for east coast ships and aux-iliary vessels. He spent three years in Otta-wa as senior naval architect, then projectsystems engineer for the DDH-280 newconstruction program, followed by twoyears in Halifax in charge of DDH-280post-commissioning trials of operationaland combat systems.

On his promotion to Captain(N), CmdreBroughton attended National Defence Col-lege. Afterwards, as Director of MaritimeEngineering and Maintenance, his respon-sibilities included CPF and Destroyer LifeExtension project development, fleet im-provements, R & D in hull systems and shipdesign, and major ship projects. He subse-quently served as Director Program Anal-ysis, responsible for the development of theDefence Program Management System.and in 1983 was appointed to the Person-nel Group for one year as the MARE Get-Well project officer. In 1984 he assumedthe position of Director of Postings andCareers Other Ranks.

Commodore Broughton was promotedto his present rank in August 1986 and ap-pointed Director-General of Recruiting.Education and Training. He was appointedDGMEM on May 23rd of this year.

He is married and has three grown chil-dren.

Turning to our lead article, the im-plementation of the diesel inspection pro-gram is proceeding as planned with the firstofficial course to be held in Halifax thisautumn. As an interim course it will beadministered by DMEE 2 with the help ofNETE. Successful candidates are expect-ed to be posted to annotated Diesel Inspec-tor positions in the naval engineering unitsand fleet maintenance groups.

The qualification of Marine Diesel In-spector should soon be recognized in theCF. With approval of a Special PersonnelQualification Requirement recently submit-ted to the Director of Military Occupation-al Structures, the diesel inspector's coursetaught on a trial basis last year shouldbecome a fully recognized occupationspecialty qualification course.

Since that trial course in July 1987, therehas been an increasing wave of support fordiesel inspections on both coasts. Dozensof inspections have been performed which,in some cases, have revealed serious prob-lems before major damage occurred and inother cases resulted in the deferral of cost-ly, unnecessary overhauls.

There is still much work that needs tobe done to attain a common high standardof diesel training, operation, inspection andmaintenance throughout the navy. To thatend, everyone's continued support of thediesel inspection program will ensure itssuccess.

WRITER'S GUIDE

We are interested in receiving unclassified submissions, in English or French, on subjects that meet any ofthe stated objectives. Final selection of articles for publication is made by the Journal's editorial committee.

Article submissions must be typed, double spaced, on 8'/:" x 11" paper and should as a rule not exceed4.000 words (about 17 pages). The first page must include the author's name, address and telephone number.Photographs or illustrations accompanying the manuscript must have complete captions. We prefer to runauthor photographs alongside articles, but this is not a must. In any event, a short biographical note on theauthor should be included with the manuscript.

Letters of any length are always welcome, but only signed correspondence will be considered forpublication.


Lettersto the Editor

Dear Sir:

I continue to read the Journal with in-terest; congratulations on another seriesof interesting articles.

lam writing to put an operator's perspec-tive on Lt(N) Sylvestre's article "An In-troduction to Stirling Engines ". He beginswith the premise that SSKs are a valid ve-hicle to support the emerging CanadianMaritime Strategy and therefore propulsionenhancements would be appropriate. Therecent White Paper clearly differentiatedbetween submarines of "position" and of"manoeuvre" which places an entirelydifferent perspective on the operational re-quirements to which the engineering designmust be subordinate.

The history of experimentation with At-mosphere Independent Propulsion Systemshas been a chequered one, marked by peri-ods of bright prospects offset by disapoint-ing results. AIP systems have failed to reachoperational status in open-ocean navies forthe very reason that the\ not supporta strategy of "manoeuvre". Lt(N) Sylvestrecites the Swedish experiment as a sign ofthe way ahead; but consider the Swedishoperational requirement — it is largely oneof "position". Swedish submarines operatein a very restricted belt of National Watersand in the Baltic. Tltey are of 1200-ton aver-age displacement (submerged) with com-plements of less than 30. Tliey operate onpatrols averaging less than a week and areas limited by food storage and oxygen ca-

pacity as much as by their propulsion sys-tem. Despite the presence of ice in theBaltic, Swedish submarines operate only onthe ice fringe.

Now consider the Canadian situation. Bythe mere facts of geography, Canadian Sub-marines must operate thousands of milesand several weeks away from home port.Tltese factors alone require an ocean-goingsubmarine of considerable dimensions andwith a larger complement. Add the require-ment for an under-ice capability and theSwedish experiment is not a relevant exam-ple. Submerged patrols within the "manoeu-vre" strategy now being advocated for theCanadian Na\y could easily reach intoweeks rather than days. A time-limitedpropulsion system is clearly an unaccept-able restraint.

We should always be ready to considernew and innovative solutions. But, our so-lutions should emphasize achievement of thestrategic arm through technology as op-posed to finding a place to apply a tech-nology by justifying the strategy.

D.C. MorseCommander

Commanding OfficerHMCS Skeena

Dear Editor,

I am pleased to see that my article onStirling engines aroused some interest, butam surprised that Cdr Morse does not seemto consider marine systems engineers to be"operators."

That aside, I regret to note that he ap-parently misinterpreted my premise whichwas that a combination of SSNs and AIPsystem-equipped SSKs, not solely the lat-ter, might be a more broadly capable sub-marine force than one comprised only ofSSNs.

On the point that small 1200-tonne RSwNsubmarines are not particularly relevant toCanadian operations, I agree. That is whyI based my thesis on the 2400-tonne Up-holder Class submarine. It should be not-ed as well that the first RSwN submarinewith Stirling engines has not yet completedsea trials. In a couple of years, when the\ the capability, they may well be oper-

ating under the Baltic ice.

We should indeed "always be ready toconsider ne\\' and innovative solutions." Forthat reason it is important to keep abreastof developing technology in other navieswhile we strive to meet the needs of ourpresent strategy.

R.A. SylvestreLieutenant Commander

MARITIME ENGINEERING JOURNAL OBJECTIVES

• To promote professionalism among maritime engineers and technicians.

• To provide an open forum where topics of interest to the maritime engineering community can be presentedand discussed even if they may be controversial.

• To present practical maritime engineering articles.

• To present historical perspectives on current programs, situations and events.

• To provide announcements of programs concerning maritime engineering personnel.

• To provide personnel news not covered by official publications.

SEPTEMBER 1988

Commodore'sCornerB\ W.J. Broughton

Your editor has kindly invited me towrite an article for this issue of the Jour-nal. As the new MARE Branch Adviser,I th ink it is only appropriate that personnelmatters be my chosen theme.

Much of what I will say is a reflectionof the deliberations of the April meetingof the MARE Council. So let me empha-size at the outset that these remarks arelargely a reflection of the excellent progressmade under the leadership of RAdm Boyle,my predecessor. You should all be awarethat he "turned over" an active, healthy pro-gram for which, I know, you would wantme to express publicly the thanks of theMARE community.

Although I just used the term "MARE"community, the Council is equally con-cerned with the NCM sea technical occu-pations. Our collective ability to man,support and renew the fleet is directlyaffected by their "health". Full strength andadequate training are essential. According-ly, deep concern was expressed by theCouncil about maintaining "production" inthe face of increased target strengths andthe additional training load as we prepareto receive the new CPFs and TRUMPedTribals. You should know that some short-falls are unavoidable within our share oftotal CF training credits. Generally, thesituation has been and should remain man-ageable. The one critical area is the MARE

ELs and E Techs. Higher recruitment rateshave been instituted to ensure steadyprogress in their trained strength.

The Council gave unanimous ap-proval-in-principle to seek the establish-ment of a new Control and InstrumentTechnician occupation. Command andDGMEM staffs will jointly develop theproposal to meet the future operations andmaintenance requirements of digital tech-nology in machinery control systems. In theinterim, a specialization course has beenestablished.

When it came to MARE officers, theCouncil received two excellent reports onMS and CS training audits. Their conclu-sions and recommendations were essentialto the refinements now under way to im-prove the timing, emphasis and content ofthat training. Briefly, the findings were:

— the basic structure of the MAREoccupation is sound

— there are no fundamental structuralproblems with the training schemesproposed in the MARE Study

— the implementation of the trainingdetails to meet this structure has notbeen thorough and accurate

— in some cases less than optimumlocation of requirements within thebasic occupation, sub-occupation andhead of department specifications hascaused some elements of training tobe included too early in the trainingprogression

- the AMSEO and ACSEO jobs mustbe for a minimum of twelve months

— for the MS sub MOC, operator train-ing had been de-emphasized morethan intended in the MARE Study.

During June, a MARE specificationreview board with MARE officers from theCommand and NDHQ, including represen-tatives of all sub-occupations, met to workthe kinks out of the specifications. Rapidstaffing and approval is planned. The nextstep in September will see Course Train-ing Standard boards working to amend thetraining documentation that controls thecontext of courses and on-job training. Soyou can see, there is concerted follow-upaction in train to overcome the weaknessesfound in the training audits.

In closing, I wish to say how delightedI am to have been offered the opportunityto be DGMEM and the MARE BranchAdviser. My role, as I perceive it, is toensure that the best possible policies, plan-ning and procedures are in place so that theproductivity of our people is happily op-timized. In this way I believe I can bestserve the community. I am committed tothat aim in these most challenging times.


The Diesel InspectionProgramBy LCdr Richard Sylvestre

Introduction

The major projects under way to upgradethe Canadian navy are placing a new andgreater emphasis on diesel engines forpropulsion and electrical power generation.Modern diesels offer advantages over rivalsystems in part-load fuel consumption,reliability, ease of on-board repair, main-tenance costs and availability of spares. Butto capitalize on these important benefits, itis essential that operating standards be kepthigh and that maintenance be based on en-gine condition rather than on traditionalcalendar-based criteria. In the past thesebasic rules of good diesel engineering prac-tice have usually not been adequately taughtor applied — particularly where surfacevessels are concerned — meaning that nowsignificant improvements will have to bemade to diesel engine operation and main-tenance standards across the fleet if thetechnical demands of the future are to bemet. Several initiatives are now addressingthis issue, one of which is the Diesel In-spection Program1 being implemented bythe Director of Marine and Electrical En-gineering with the assistance of the NavalEngineering Test Establishment.

Background

Historically there has been little successin ascertaining diesel engine condition priorto repair or overhaul. Engines have beenoverhauled at considerable expense whetherthey needed it or not, and some have beenrun almost to the point of self-destructionbecause defects were not recognized in theirearly stages. Operating standards have alsobeen somewhat less than ideal, leading in-variably to premature failures. This unsatis-factory state of affairs can be attributed toa lack of effective diesel equipment healthmonitoring techniques and to inappropri-ate marine engineering occupation courses.A recent study at Fleet School Halifax2

showed that diesel courses lacked sufficienthands-on training and were not adequatelypreparing marine engineering personnel tooperate and maintain engines at sea.

Until recently these problems did not re-ceive a great deal of attention. Certainlythe increasing costs of diesel support forthe aging submarines and auxiliary vesselswere a concern, but since the major war-ships only used diesels for emergency orstandby electrical power the problems neverassumed major importance. That changedovernight, however, when the design for theCanadian Patrol Frigate was determined.The CPF's dependence on sophisticated,modern diesels for all cruise propulsion andelectrical power elevated the navy's concernfor diesel operation and maintenance tohigh-profile status.

Initiatives now under way in the dieselfield include the construction of a well-equipped training facility and the revisionof occupation courses in Fleet School Hali-fax, implementation of a diesel inspectionprogram, replacement of obsolete engines,various SHIPALTs to improve filtration,lubrication and oil testing, and improvedcontrol of spare parts' quality. In addition,overall diesel support policy for the entireinventory of about 500 engines is beingpromulgated in the Marine Diesel EngineEquipment Logistics Directive3, anddiesel entries to the Naval EngineeringManual are being revised and expanded.

Diesel Condition Analysis

Overhauling engines at fixed calendarintervals regardless of accumulated runninghours or engine condition is a simplistic ap-proach which often introduces new prob-lems in the process of correcting old ones.The move towards logical, condition-basedmaintenance (CBM) is therefore welcomed.The difficulty in this new approach to main-tenance is in reliably determining enginecondition. The established naval equipmenthealth monitoring (EHM) techniques ofspectrometric oil analysis and vibrationanalysis have been ineffective for this pur-pose, so there is a requirement to adopt newtechniques. Better procedures for oil and

coolant testing are now being implement-ed, and investigations are under way toidentify suitable, automated electronicEHM equipment. Although these lattermethods have high potential, they are stillin early development and it will be manyyears before their impressive potential canbe realized.

Lacking any other form of definitiveEHM technique to support CBM, it is es-sential that the navy's technical personnelbe more effectively utilized. This can bedone by training select individuals in theskills of engine condition analysis. As theUnited States and British navies have bothproven by their respective diesel inspectorand specialist programs, significant gainscan be made in increasing engine reliabili-ty and reducing maintenance costs. Al-though both these navies are investigatingelectronic EHM techniques as well, theyforesee much value in the continued em-ployment of personnel for engine diagnosis.

Diesel Inspections

In July 1987 a highly acclaimed dieselinspector's course was given in Halifax byex-USN diesel inspectors. During and af-ter the course, on-site inspections of oper-ational diesel units revealed an alarminglack of expertise among Canadian dieseloperators and maintainers. Common dieselequipment deficiencies across the fleet in-cluded excessive leaks and accumulationsof dirt and engine fluids, faulty instrumen-tation, incomplete and inaccurate enginerecords, scored cylinder liners, piston blow-by, faulty injectors, worn rocker arms andincorrect lock-wire procedures. In partic-ular cases, broken piston rings, defectivebearings, unserviceable emergency tripsand dangerous fuel leaks were discoveredbefore major engine damage occurred.

The evidence arising from the inspec-tions caused a great deal of discussion,which eventually led to the decision to im-plement a Canadian diesel inspection

SEPTEMBER 1988

program' using ideas from both the USNand RN. The concept as described here isnot complicated. It is a fundamental EHMtechnique based on trained observation ofdetects. A diesel inspection will entail athorough mechanical and administrative ex-amination, wherein a qualified diesel in-spector, over two or three days will:

a. assess the state of al 1 technical doc-umentation associated with the en-gine, including manuals, logbooks,oil and coolant analysis records andmaintenance records;

b. assess the general housekeepingand instrumentation state of the en-gine;

c. by removing inspection covers andcomponents as necessary, examinewear components such as bearings,rings, cylinder liners and valves,and examine the adjustment of fuelracks, timing mechanisms, gover-nors and safety devices;

d. by monitoring the engine undernormal operation, identify defi-ciencies indicated by leaks, incor-rect operating temperatures,pressures and flow rates, andreduced power output; and

e. prepare a formal inspection reportwith computer assistance for dis-tribution to the ship and relevantshore authorities.

Diesel inspections will provide detailedassessments of mechanical condition for theinternal engine components such that cor-rective maintenance may be targeted tospecific detects. This should greatly reducethe overhauling of engines needlessly, andwill identify minor malfunctions before theydevelop into serious failures. In addition totheir obvious util i ty in making maintenancedecisions, regular inspections should also:

a. increase the fleet's awareness andapplication of correct proceduresfor operation and maintenance,

b.

thereby reducing the incidence ofpreventable corrective main-tenance; and

serve as a constant and visible in-dicator of the fleet's diesel opera-tion and maintenance standards.

Initially, inspections will be done annu-ally and during pre- and post-refit/overhaulon most engines over 200 kW, and on othercritical or costly engines. As the programis integrated into the maintenance manage-ment system, inspections will be called upby preventive maintenance schedules andmay be extended to include other engines.

Inspectors

The primary role of the diesel inspec-tors will be to perform inspections in ac-cordance with a diesel inspector's handbookand relevant technical orders. Other dutieswill include:

a. assisting and advising ships' staffsin trouble-shooting diesel engineproblems;

A 6.2-MW Pielstick cruise engine ready for installation in a Canadian patrol frigate. Tlie CPF's dependence on sophisticated, moderndiesels for all cruise propulsion and electrical power has given diesel reliability high-profile status within the navy.


h. advising NDHQ of deficiencies inpreventive maintenance schedules.equipment support lists and otherdocumentation;

c. advising the training establishmentsof apparent training deficiencies inthe fleet; and

d. assisting and advising as appropri-ate on diesel engine trials.

Most of the inspectors will be marineengineering articifers. and when employedin an official capacity as command dieselinspectors will occupy established shorebillets for two- to three-year tours. On com-pletion of a tour an inspector may resumenormal seagoing duties (albeit with a valu-able and much enhanced knowledge ofdiesel matters), and subsequent shore post-ings may include senior inspector positionsin local or NDHQ establishments.

l̂ '̂ ^

^^HH^B^H

Diesel inspector training will comprisea comprehensive three- to four-weekcourse, with selection based on experienceand past performance as well as on in-dividual availability and other manning re-quirements. The course is modelled on theUSN inspector training and will becontracted to a professional commercialagency until such time as it may be donecompetently in-house. Subsequent qual if i -cation to the diesel inspector's occupationspecialty specification wil l involve on-the-job training, and normally will be done inthe first few months of assuming a juniorinspector position.

The Way Ahead

With the commissioning of the CPFs andthe upgrading of many existing diesel in-stallations over the next ten years, the navywill come to rely on diesel engines for atleast 80 percent of electrical power andmore than 50 percent of propulsion power.These figures attest to the urgency of thediesel improvement measures describedhere. Thorough implementation of the in-spection program and the other importantinitiatives will ensure that we manage ournew diesel technology at least as well aswe have done with steam and gas turbinesin the past.

References:

1. 12815-119 (DMEE 2) 22 March 1988, DieselInspection Program.2. CFFSH: 4500-1 (ENG/DCOMPT(D)) 8June 1987.3. 12815-0 (DMEE 2) 29 January 1988, DraftMarine Diesel Engine Equipment LogisticsDirective.

LCdr Sylvestre was the DMEE 2 DieselProjects Officer before taking up his pres-ent assignment last June as MachineryControls Project Officer in DMEE 7.

Applying the basic rules of good diesel engineering practice is the key to the na\y'snew diesel inspection program. TJie program holds great promise for significantly in-creased diesel reliability throughout the fleet.

SEPTEMBER 1988

ASW FrigateElectrical PropulsionThe Way AheadBy W.A. Reinhardt and J.R. Storey

IntroductionElectrical propulsion for ships has many

advantages when compared to the variousforms of conventional mechanical propul-sion. These advantages include:

* Inherent low noise;* Minimized fuel consumption;* Infinitely variable speed and precise

control of propeller rpm;* Simple and rapid reversal;* Inherent cross-connect capability;

and* Greater flexibility in the propulsion

system design and ship arrangements.(* For Canada there is the additional ad-

vantage of easy manufacturability inCanada in time of war.)

Such advantages have permitted electri-cal propulsion systems to find applicationsin aircraft carriers, tankers, ocean liners,submarines, icebreakers and oceanographicresearch vessels. To date, however, an all-electrical propulsion system has never beenused in a frigate. This has generally beenattributed to the somewhat greater weight,size and acquisition cost of electrical sys-tems compared to mechanical propulsionsystems, but these disadvantages can beminimized by the use of modern designtechniques, equipment and materials.

In light of developments in high-power,solid-state electrical devices, and today'sgreater emphasis on low fuel consumption,reduced manning and low noise signaturefor anti-submarine vessels, electrical

propulsion is a viable alternative toconventional drive trains. The Royal Navy,for example, is using an electrical cruisepropulsion system for its Duke Class (Type23) ASW frigate.

Since gearboxes and controllable-pitchpropellers contribute significantly to shipnoise, it is especially desirable to eliminatethem from the propulsion systems of ASWfrigates. One solution is to use electricalpropulsion power for the entire range ofASW frigate speeds.

With this possibility in mind, the Direc-torate of Marine and Electrical Engineer-ing initiated a feasibility/design study anda simulation study for an all-electric propul-

Waterline LengthBeamDisplacementEndurance

Speed

DIMENSIONS130 m14.4 m4354 tonnes5500 nm @ 18 kts3200 nm @ 23 kts1500 nm @ 28.5 kts28.5 kts (full power)25.9 kts (GT gen. alone)23.1 kts (diesel gen. alone)

PropellersPropulsion Motors

Prop. Generators

Prop. Motor ControlPropulsion Power

PROPULSION PLANT(2) fixed-pitch(2) 12.5-MW synchronous motors14160-volt](3) 6-MW gas turbine gen. sets|4160-volt, 60-Hz, 3-phase](3) 4-MW diesel gen. sets [4160-volt.60-Hz, 3-phasel(2) 12.5-MW cycloconverters25 MW

2 X 12.5-MW CYCLOCONVERTERS 6-MW GT GEN

1-MW DIESEL GEN IP/S)

6-MW GT GEN IP/SI

PROP MOTOR 4-MW DIESEL GEN (P/S)

4-MW DIESEL GENNote: P = PORT. S = STARBOARD

Fig 1. Profile of Proposed COEDAG System


sion system for a frigate-type ship. Theobjectives of these studies were:

a. to determine the feasibility of satis-fying frigate operational and tech-nical requirements by electricalpropulsion; and

b. to develop a concept design whichwould achieve the best results.

In this paper, a frigate design is outlinedwith background information on the shipdesign and electrical technology. The sys-tem design and machinery arrangement areexamined, the advantages and disadvantagesdiscussed, and the results of a simulationstudy are reported. Finally, conclusions andpossible future developments are presented.

Ship Design

The design study demonstrated that anall-electric propulsion system, using cur-rent Canadian icebreaker propulsion plantdesign practices, is a feasible and viable al-ternative to the conventional mechanicalpropulsion plant. One of a number of pos-sible general arrangements is shown inFigure I , with the electrical power plantarrangements shown in Figure 2.

Machinery Arrangement

The machinery arrangement demon-strates the flexibility of the electric propul-sion system, in that the prime movers donot have to be lined up with the shafts orgearboxes. The motors are installed in stag-gered motor-rooms as far aft as possible,and are limited only by shaft rake, flood-ing considerations and clearance of thepropeller. The arrangement offers improve-ments in survivability, acoustic signatureand reduced infra-red susceptibility of thegas-turbine exhausts. The removal of thelarge central trunks frees valuable space.

Ship's Service

Ship's service 440-volt, 3-phase, 60-Hzpower is provided by two 1-MW syn-chronous motor-generator sets poweredfrom the propulsion bus. In addition, two1-MW diesel generator sets are included asbackups, in keeping with Canadian navypractice.

Design Rationale

Frigate Design

The design study modelled a frigate us-ing recent NATO frigate characteristics anddisplacements. This baseline frigate was de-veloped around a CODOG (CombinedDiesel Or Gas turbine) system which wasalso used as a comparison for the electricfrigate.

DO GO \^7 DO4.0(T)M* 4.0(T)M* 5.9(jT)MW 4.o(V) M#

~* * X X~ X X X X

Y _.S.S. INTER- S.S., . Xa 1 0 1 SET CONNECTION SET | P | - , 1

' ' QU/TTrj-l i ^ * A -JU-A .0(7) MW b i lLH .0(7) MW A /^\ F ~~l I F ^

X X X X X X600 KVA , __L___ 60° KVA

1 M * t xs.s. LOADS s.s. LOADS!

S g -, A S 5^ ^ ^ 440 V SHORE CONN. 1.0 M*-̂ « SJ

S ° V 2 S=; IS.S. LOADS S.S. LOADS ? *

RINGMAIN X i 1 i 1 SHIP— PROPULSION —-SERVICE

X X X X X X

1 i n ^— ̂ uw 1 n ^— ' \tx

^PP . (T)5.9 M# ^T S^ 5.9 MW/"JP\U o:

d x x x x x x xx '

X XXX X X XXX X

INTERCONNECTION SWITCHI 2 5 M W < M > PORT PROFU.SION STARBOARD PROPULSION (u\\? = MI

V.V MOTOR MOTOR ^MJI.i.bMW

Fig 2. Power Plant Arrangement

PLATFORM CHARACTERISTIC

Displacement (tonnes)Fuel (tonnes) : To Meet Endurance

Consumption (Lifetime)Per 100 hrs: (Normal)

(Defence)(Quiet)

Shaft Power (MW): at 15°Cat 38°Cat 43°C

Volume of Machinery and Fuel (m3)

COEDAG

4,354402

111,000113123177252525

1,362

CODOG

4,247554

150,221153163300

3026.424.9

1,188

Table 1: Platform comparison

The electric frigate was next evolvedfrom the baseline frigate with considerationfor Canadian navy design practice. Theelectric propulsion frigate is COEDAG(Combined Electric Diesel And Gas tur-bine).

A comparison summary of the electricand baseline CODOG ships' characteris-tics is given in Table 1.

Electrical Technology

The propulsion motor is the most sig-nificant component in the propulsion sys-tem and requires careful selection. The DCmotor is larger than an AC motor of thesame power rating (see Figure 3) and istherefore unsuitable for a frigate applica-tion. The AC induction motor is air-gapsensitive (i.e. requires a small concentricair gap) and hence is more susceptible to

SEPTEMBER 1988 9

damage from shock and deflection of theshaft: a serious disadvantage for a frigate.The AC synchronous motor suffers noneof these problems.

Three AC systems that can be used todrive a fixed-pitch propeller are shownschematically in Figure 4. The load-commutated inverter (LCI) drive has a widespeed-range, but the minimum speed can-not be lower than ten percent of rated speeddue to insufficient motor EMF to self-commutate the thyristors. The cycloconvert-er drive provides speed control to zero rpm,comparable to DC drive systems. The force-commutated inverter (FCI) drive has onlylimited power levels, as solid-state devicessuch as gate turn-off thyristors in the re-quired ratings are still under development.

With regard for the preceding observa-tions and the desire to stay within the Cana-dian technology base, AC synchronousmotors with cycloconverters were selected.Figure 5 shows the propulsion motor andcycloconverter developed for the CoastGuard Type 1200 icebreaker. The motor israted for 9.4 MW, which is approaching the12.5-MW rating required by the frigatemodel.

Propulsion Bus

For reasons of improved survivabilityand maintainability, the ring main systemwas selected as shown in Figure 2. The4160-volt system was chosen due to thedecreased size of the motors and genera-tors, and because of the lower current rat-ings (smaller cables and circuit breakers).Cable selection and installation must alsotake into account electromagnetic interfer-ence and compatibility (EMI/EMC) andthe harmonic distortion created by thecycloconverter.

Ship's Service

The ship's service power must meet therequirements of STAN AG 1008. A numberof different methods to derive ship's serv-ice power from the propulsion bus were ex-amined, including transformers, invertersand motor-generator (MG) sets. Transform-ers and inverters were discarded due to acombination of poor power quality and EMIproblems. MG sets were examined in moredetail and then incorporated.

Propulsion Generator Prime Movers

It was determined that between three andseven propulsion generator sets could beused with regard to reliability, maintaina-bility, complexity, weight and space limi-tations, etc. Working with the requirementof a minimum of 25 MW of propulsion

R-CLASS DC MOTORICEBREAKER RATING 5600 kWMAX CONTINUOUS RATING 7500 kWVOLTAGE 870 V DCWEIGHT 149.688 kg

TYPE 1200 AC MOTORICEBREAKER RATING 6000 kWMAX CONTINUOUS RATING 9400 kWVOLTAGE 1900 V ACWEIGHT 79.833 kg

Dimensions in mm

Fig 3. R-Class (DC) and Type 1200 (AC) Motors

ISOLATION TRANSFORMERSTRANSFORMATEURS D'ISOLEMENT

Fig 5. Coast Guard Type 1200 Icebreaker Propulsion System Under Test

10 MARITIME ENGINEERING JOURNAL

CONTROL CONTROL

IVOLTAGE SOURCEINVERTER FEED) A. LOAD COMMUTATED INVERTER

(SYNCHRO-CONVERTER)

CVCLOCONVeRTER

VOLTAGECONTROL

FREQUENCYCONTROL

e. CYCLOCONVERTER DRIVE

FIELD SUPPLY

(PF CONTROL)

SYNCHMOTOR

(VOLTAGE SOURCEINVERTER FEED}

DSUPPLY

IPF CONTROL)

C. FORCED-COMMUTATED INVERTER

Fig 4. Three AC Propulsion Systems for a Fixed-Pitch Propeller

OPTION

ABCDEFGHI

B/LCODOG

LIFETIME FUELCONSUMPTION

(Tonnes)

155.500128,110115.220111.000107,160108.380119,920107,630147,540

150,221

% LIFETIMECONSUMPTION

LESS THANBASELINE

-3.514.723.326.128.727.820.228.31.8

0

FUELTO MEET

ENDURANCE(Tonnes)

490481414402371371483375705

554

% FUELTO MEET

ENDURANCELESS THAN

BASELINE

11.613.225.327.433.033.012.832.3-27.3

0

PROPULSIONSYSTEMWEIGHT(Tonnes)

681709740768872887687838674

506

Table 3: Summary of options [Fuel consumption and weight]

SEPTEMBER 1988

OPTION

A

B

C

D

E

F

G

H

1

NO. OF ENGINES

6

B1

42

33

25

16

22

15

21

ENGINE RATING IMWI

AND TYPE

(GAS DIESEL)

6.0 IGI

6.0 IGI4.0 IDI

6.0 IGI4.0 IDI

6.0 IGI4.0 (Dl

6.0 IGI4.0 IDI

6.0 IGI4.0 IDI

12.0 IGI4.0 IDI

12.0 IGI4.0 IDI

15.0 IGI4.0 (D)

ELECTRICAL SYSTEM = Common Bus

Table 2: Summary of generatorsystem options

power, nine different configurations wereselected for evaluation as per Table 2. Fuelconsumption and fuel weight were calcu-lated for the nine configurations and sum-marized in Table 3. Lifetime fuelconsumption is based on the operating pro-file of Figure 6, which is 20 years of peace-time (150 days per year) and five years oftension/conflict (220 days per year) oper-ation.

The best five configurations were stud-ied further; a comparison summary is givenin Table 4, and a ranking in Table 5.

System D was chosen as the system todevelop because it had the highest rankingand offered the greatest potential to demon-strate the flexibility of electric propulsion.

Electric Propulsion Plant

The generators are heavy-duty marinetype, brushless, synchronous machinesdesigned with a 0.65 power factor.

The two propulsion motors are 10-poleAC, synchronous machines rated at 12.5MW with a reversible speed range of 0 to200 rpm. Each motor is speed-controlledby a cycloconverter over the frequencyrange of 0 to 16.7 Hz.

The cycloconverter, shown schematical-ly in Figure 7, functions by means of thyris-tors in a back-to-back connection. Theuseful frequency range of a cycloconverter,due to harmonics, is zero to one half theinput frequency. The 16.7 Hz required bythe propulsion motors is well within thislimit.

Power plant control wil l be by amicroprocessor-based ship's automatic

11

OPTION

Power(MW): @ 15°C@ 38°C

Fuel Consumption (Tonnes);Lifetime (normal operation)Endurance (normal)Per 100 hrs (normal)Per 100 hrs (quiet)

Weight of Propulsion Equipment and Fuel (Tonnes)Displacement (Tonnes)Prop. Eqpt. and Fuel Weight as a Percentage of DisplacementVolume of Prop. Eqpt. and Fuel (m3)Deck Area of Equipment (m2)Reliability of Prime MoversLifetime Maintenance Costs ($ Million)Initial Generator Set Purchase andInstallation Costs ($ Million)

C

32.027.0

115,220414

117.6196.71195

433727.531319224

.79198.68

24.90

D

30.026.3

111,000402

113.3176.81210

435427.791362237

.78456.20

24.71

E

32.029.5

107,160371

109.3247.31281442428.961490280

.78776.52

28.09

G

32.029.1

119,920483

122.4252.61219

436227.951455231

.67919.27

20.51

H

32.030.6

107,630375

109.8300

1251439428.471519283

.63956.56

25.67

Table 4: Comparison summary

OPTION

Total PowerFuel Consumption:

NormalQuiet

Total WeightSpace RequirementReliabilityMaintainabilityCapital CostSurvivabilityNoise & Vibration

TOTALS

MAXIMUMMARKS

10

101010101010201010

110

C

10

68101010614910

93

D

9

8999910151010

98

E

10

10106699101010

90

G

10

56997620810

90

H

10

10766691359

81

Table 5: Ranking matrix

power management/control system whichwill select the most efficient mode of oper-ation.

Discussion

The potential benefits of electric propul-sion for an ASW frigate may be best real-ized by reviewing the advantages anddisadvantages of the system.

Noise and Vibration

As submarine noise-reduction measuresbecome more effective, the primary task ofthe ASW frigate (to locate targets) becomesmore difficult. The limitations of hull-mounted sonars due to hydrodynamic noiseare well known; hence the development ofsonar arrays which can be towed manymetres astern in undisturbed water. Yet inspite of the length of tow the performanceof the array can be severely degraded by

the ship's radiated noise, especially at lowspeed.

When ships move through the water atspeeds below the cavitation inception speedof the propeller, the dominant radiated noiseis normally that generated by the mainpropulsion and auxiliary machinery. Thecombination of gas turbine and controllablepitch propeller does not lend itself well tolow noise at the low rpms that are requiredduring sonar surveillance.

Figure 8 shows typical straight-line ap-proximations of radiated noise from steam,gas turbine and electric propulsion systems.Mounting the gas turbine and gearbox ona raft has provided a marked improvementover the steam turbine ship, but at low speedthe controllable pitch propeller becomes anoise problem. An electric propulsion driveusing a fixed-pitch propeller system

eliminates the main gearbox and thecontrollable pitch propeller, thus reducingthe low-speed noise.

Studies conducted for the RN Type 23frigate indicated that a diesel-electric sys-tem could reduce the octave-band noise lev-els by 10 dB. A gas turbine electric system,with the same degree of noise reductionmeasures can give further improvementsdue to the basic characteristics of the primemovers. Still greater benefits are realizedby locating the power generators high in theship, thereby lengthening the noise trans-mission path to the water.

A gas turbine electric ship with the gasturbines high in the ship is expected to be15 to 20 dB quieter than a mechanical driveship in broad-band noise and even betterin narrow-band noise performance. Thisreduction in noise greatly increases theship's active and passive sonar capabilityand decreases its likelihood of detection bya submarine.

Minimized Fuel Consumption

Comparing the data for AC electricpropulsion with that of the baseline CO-DOG ship, the electric ship will be approx-imately 30 to 40 percent more fuel efficientover its life.

The effects on efficiency of the dieselsand small gas turbines can be readily seenfrom Table 3. The small gas turbines makethe electric frigate more fuel efficient whenoperating in the ASW mode, when gas tur-bines would be required for low noise atlow speeds.


8000-

W 7000-rr

0X 6000 -

zS 5000 -

UJ£L

4000-Uli[ij 3000-_1

2000 -

1000-

0 ,l!l2 4 6

Ik8 10 12 14 16 18 20 22 24 26 28

Fig 6. Lifetime

SPEED (KNOTS)

Operating Profile

THR

I

E PH

:ig

4SE I

7.

36

MPUT

2

2

i

i

Dual converter "A"

^^ f^ OUTPUT

33 ¥ | ¥

Dual converter "B"

rhf rt̂OUTPUT

£ g ^ Y ¥ ¥

Dual converter "C"

r^ i~t̂OUTPUT

\ A v i i

Three-Phase, Six-Pulse,-Leg Cycloconverter

The fuel consumption per hundred hoursof operation, Table 4, follows the samecurve as the lifetime profile (i.e. if the shipspends 7.5 percent of its time at 18 knots,this corresponds to 7.5 hours out of thehundred hours). The fuel required for onehundred hours of operation is stated in Ta-ble 1 for both normal and quiet operations.

The better fuel efficiency is due to theinherent cross-connectability of the differ-ent generator sets with the motors. Thepower generation can continually bematched to the propulsion motor load andthereby follow and match the ship's pow-er/speed curve much closer than a mechan-ical ship, as shown in Figure 9.

In essence, the electric ship has the ad-vantages of the quietness of the gas turbinesand the efficiency of the diesel primemovers. It can give more for less; that is,it goes farther on less fuel and does it morequietly.

Manoeuvring

The electric propulsion system providesan infinite number of operating speedsthroughout the motor speed-range (-200 to0 to 200 rpm), without any time limitationsexcept those imposed by total fuel carried.Acceleration and deceleration within the

RADIATEDNOISE —(Vdb)

\

STEAM

GAS TURBINE

/ /

/ *

/ // /

/

ELECTRIC

I I \0 10.0 15.0

SPEED IN KNOTS

Fig 8. Propulsion System Vibration Characteristics

1

20.0

speed range is controlled by the propellerand shaft thrust limitations and generatorprime mover characteristics which may im-pose some limitations on "bang-bang" typeoperations. Reversing the motors is accom-plished by simply changing the cyclo-converter control reference signal.

When a crash stop is executed, negativepower is generated by water flowing throughthe propeller, and by the system's inertiaafter the propulsive power has been re-moved. Usually this negative power isgreater than the level that can be absorbedby the engines, ship's service, losses, etc.,

SEPTEMBER 1988 13

and therefore accelerates the prime moversand MG sets. The overspeed can be par-tially contained by the governor, but thegenerator set could still be tripped on over-speed.

To overcome this deficiency, the primeabsorption capacity of the system has beenincreased by the use of dynamic brakingresistors. The resistors, based on icebreakercontrol design, are sized at approximatelyten percent of propulsion plant size and canbe used with any combination of diesel andgas turbine generator sets. The resistors willbe switched in when a two-percent speedrise is detected, and will remain connectedonly for the duration of the regeneration;approximately ten seconds.

Survivability

The two major survivability considera-tions are underwater shock and direct phys-ical ballistic damage.

The potential shock problem area for theelectric system is considered to be the mainmotors, which are envisaged as hard-mounted units due to their weight and align-ment requirements. The main motors arebased on icebreaker technology which re-quires a limited level of shock hardening,mainly in the vertical and longitudinaldirections. Other equipment will be shock-mounted in standard military fashion as re-quired.

Since direct physical damage involvingpenetration of the hull would likely putequipment in the affected compartment outof action, protection is only practical byphysical separation. The layout flexibilityof the electrical system allows the primemovers to be located considerable distancesapart and the main motors to be in stag-gered compartments.

Reliability

A number of possible propulsion systemevents and problems were analyzed to iden-tify the operational conditions for the ves-sel. Where applicable, the results for theCOEDAG plant were compared with thosefor a conventional CODOG plant for thefollowing:

* one main-engine generator shut downfor maintenance;

* one power generation compartmentextensively damaged;

* partial loss of power supply to a mainmotor;

* loss of cooling of a main motor; and* loss of a ship's service generator set.

The principal conclusion that wasreached from the investigation of the postu-

lated incidents is that there would be limit-ed effect on the capability of the ship in lightof the flexibility of the system configuration.The COEDAG ship is considerably superiorto a CODOG vessel in this regard. It is feltthat the increased complexity of the systemwas unlikely to cause significant problemsdue to the high intrinsic reliability of mostof the major components. Planned main-tenance and accidental or action damage arethe most probable causes of equipment un-availability, and the basic operationalconsequences are summarized in Table 6.

Manufacturability in Canada

The Canadian Coast Guard is presentlyconstructing AC electric propulsionicebreakers using Canadian sources. How-ever, there is no similar Canadian engineer-ing or manufacturing capability for largemarine gearboxes, controllable-pitchpropeller systems or high-power/torque,flexible shaft couplings. At present thesecomponents come from the United Statesand Europe, and in time of conflict thesesources could be expected to be disrupted.

Canada presently has the design andmanufacturing capability for propulsiongenerators, motors and cycloconverters andcould probably acquire the rights tomanufacture diesel engines and gas turbinesunder licence.

Electromagnetic Interference/Compati-bility

Electromagnetic interference is anincreasing problem for the ever-sensitiveelectronics in ships, and can be caused byinduction, conduction and radiation. Sincethe propulsion system, distribution cables,and virtually all electrically powered equip-ment are potential EMI sources, a gooddesign philosophy and construction meth-odology are of paramount importance inreducing the effects of EMI in an electri-cally driven ship.

As much as possible, the propulsion net-work should be kept in a confined area ofthe ship, distant from sensitive equipment.Each propulsion bus cable must be care-fully shielded and possibly housed in steelconduit; in which case, three-phase sym-metry must be maintained to reduce cur-rents induced in the conduit, and heatingeffects due to hysterisis. Sensitive cablespassing in the vicinity of high-voltage ca-bles must also be properly shielded.

Waveshape Distortion

Harmonics and waveshape distortion arecreated by the waveshaping function of thecycloconverter. The higher the cyclo-converter output frequency the greater theharmonic contribution transmitted to the

30-

15 -

Ship (propeller)

15

Speed (knots)

Fig 9. Power/Speed Curves

30


motor and reflected back to the propulsionbus.

The level of distortion of the voltage onthe ship's service bus is limited by STA-NAG 1008 to total harmonic distortion(THD) not exceeding five percent, with sin-gle harmonics not exceeding three percent.Since ship's service power is provided byMG sets, the distortion of the propulsionbus waveform need not be controlled with-in the low limits for ship's service voltagespecified in STANAG 1008. Nevertheless,it is important to determine the distortionof the propulsion bus waveform in order thatthe effects of harmonics are recognized insizing components of the electric plant. Forexample, cables will need to be oversizedby 10 to 30 percent; generators will requirelarge amortisseur windings and more iron;switchgear will have to be oversized, andprotective relays, automatic voltage regu-lators and control equipment will have tobe immune from harmonics.

In theory, harmonic distortion can in-duce vibrations in the propulsion motorsthat could cause underwater noise. Testingis planned in the near future on the CoastGuard icebreakers to determine the extentof these vibrations.

Size, Weight and Acquisition Cost

The electric propulsion plant, based onexisting industrial technology using air-cooled machines and control and switch-gear designs, is approximately 50 percentheavier than the mechanical system. It alsorequires more space. Consequently, an elec-tric frigate must be longer to accommodatethe extra weight and volume. The longership has improved seakeeping capability.

higher top speed for the same power, anda larger platform for mounting combat sys-tems. This longer, heavier ship, though,does have a greater front-end cost. As theelectric frigate can sail farther on less fuelthan a mechanical ship, fuel savings arerealized that will provide payback of the in-itial cost, but the amount will be depen-dent on the future cost of fuel.

System Simulations

Computer simulation was used to inves-tigate the electrical system and shipmanoeuvring performance under variousoperating conditions.

Electrical Simulation

The electrical system simulation wasperformed by modelling each componentin the system; i.e. cables, motors and gener-ators appropriate for the range of frequen-cies (0 to 1 000 Hz). The sub-networks werecombined to make a system model. Distort-ing currents of the correct magnitude andfrequency1 were injected into the networkand the resulting voltages at various pointsin the system were evaluated.

a. Harmonics (Voltage and CurrentDistortions). The worst case ofTHD was 18 percent, with a worstsingle harmonic of nine percent.This indicates that care in the selec-tion and design of the equipmenton the propulsion bus is required,and that MG sets are necessary forclean ship's service power.

b. Transient Analysis. The transientanalysis simulation simulated theextent to which disturbances occur-ring on the propulsion bus would

COEDAGLoss of:

1 GT gen (normal mode)1 GT gen (quiet mode)1 diesel gen (normal mode)1 diesel gen (economical mode)1 motor1 cycloconverter

CODOGLoss of:

1 GT (normal mode)1 GT (quiet mode)1 diesel (normal mode)1 diesel (economical mode)gearbox

PERCENTPOWER

AVAILABLE

806787675050

505010000

SPEEDAVAILABLE

(KNOTS)

272027202323

24243000

Table 6: Summary of reliability assessment

penetrate via the MG sets onto theship's service bus during shipmanoeuvring. The voltage and fre-quency transient s imulat ionsdemonstrated that the disturbancesare well within the limits of STA-NAG 1008.

c. Load Level/Fault Analysis. Loadflow and fault level diagrams for theelectrical ring main systems weregenerated. Fault levels due to faultsat all main breakers were calculat-ed, and showed little variationaround the ring main propulsionbus because of low cable im-pedance. Fault levels at half cycle,three and eight cycles were calcu-lated with results well within thecapabilities of the circuit breakers.

Load level analysis was performed forvarious propulsion plant configurations. Itwas discovered that a minimum of twogenerators were required to provide suffi-cient power for the main motors and ship'sservice requirement. This minimum re-quirement arose because at the lowerpropulsion power levels the generators werelimited more by their MVAR capacity thanby their MW capacity. The high reactivepower demand was caused by the cyclo-converter. At low motor speeds (lower out-put frequencies) the output voltage of thecycloconverter must be decreased to pre-vent motor overfluxing.

Ship Manoeuvring Simulation

The simulation models for the diesels,gas turbines, cycloconverters, motor-generator sets, dynamic braking resistorsand propulsion motors were developed andinterconnected through an overall controlsystem. The models of the diesels, gas tur-bines and cycloconverters also had theirown dedicated control systems.

The real-time simulation encompassedvarious combinations of propulsion plantscenarios, loads, control system characteris-tics and transient constraints.

The ship manoeuvr ing transients(acceleration, crash stop—full ahead to fullstop) required load control to maintain thefrequency within the specified limits ofSTANAG 1008. This load control wasaccomplished by controlling the primemover governors and by using dynamicbraking resistors to absorb the regenerativepower generated during ship manoeuvring.

The simulation results showed that theperformance available from an electric shipwould match or exceed a similar mechani-cal ship in terms of reversing time, stop-

SEPTEMBER 1988 15

ping distance, acceleration, etc. The shipaccelerated to 25 knots (90 percent of topspeed) in 40 seconds, and to top speed in60 seconds. The ship stopped in 50 seconds,within 400 metres (3 ship lengths), fromtop speed using the braking resistors to helpabsorb the regenerated power.

The simulation aided in establishing andconfirming the correct control sequencingand limits for the propulsion system.

Future Development

This section addresses technological de-velopments that are still maturing or havenot yet been used in a marine application.The discussion of the developments willlargely address what is possible in the im-mediate future and outline the anticipatedbenefits and/or drawbacks.

Immediate volume and weight reduc-tions could be made to the motors andgenerators by utilizing a higher tempera-ture insulation (180°C) in lieu of 155°C forthe windings. This would provide a five-to ten-percent reduction in overall weight,and possibly enhance the sprint capabilityof the ship.

The use of a higher propulsion bus volt-age (6.6 or 10 kV) would lead to size andweight reductions in the motors, genera-tors, cabling and switchgear. But with thethyristors presently used in the cyclo-converter it would mean an increase in thenumber of thyristors required to handle thehigher voltage, thus increasing the size ofthe unit .

Increasing the propulsion bus frequen-cy to between 60 and 400 Hz would enablethe gas turbine generators to operate with-out a gearbox, thereby decreasing genera-tor size and weight. An added benefit ofhigher frequency operation would bereduced voltage waveform distortionsgenerated by the cycloconverter. The dis-tortions are a function of the input to out-put frequency ratio of the cycloconverter.The higher frequencies require fastercontrol strategies and components.

Direct water cooling of the rotor and sta-tor of the main motors and of the cyclo-converters produces a large reduction in sizeand weight. The cycloconverter's weightwould be affected only slightly, but its vol-ume would decrease by 33 percent. Themotor size would be reduced by 50 percent.The generator stator could be water-cooled,but cooling the rotor is complicated due torotating, high-speed shaft seals. The aux-iliary cooling systems would have to be-come larger, but would not necessarily bemounted on the equipment itself.

The use of high-energy density materi-als with high magnetic permeability woulddecrease the size and weight of the motorsand generators. Weight and volume reduc-tions of 40 percent have already beenachieved by Siemens in the design of a1.1-MW motor. The PERM AS YN motoruses samarium cobalt and has 20 percentless loss than a comparable DC machine.

New thyristors rated at higher voltageswill decrease in size and weight. The higherpower gate turn-off thyristors coming onthe market will allow much better controlof the power converter. With proper controlthese thyristors can be triggered to coun-teract the expected harmonics and voltagewaveform distortion. The control systemwould have to process non-linear, transcen-dental equations for the magnitude of wave-form.

Conclusions

An electric propulsion system has beendefined in suf f ic ien t detail to giveconfidence in its ability to meet or exceedthe specific targets initially laid down. Ithas been shown that in many areas whereoperational effectiveness is concerned, theelectric ship has markedly superior perfor-mance over the baseline CODOG ship. Theelectric ship scored higher under moreonerous operating conditions such as stateof tension, conflict, or damage; a valuablecharacteristic for any warship.

Fuel consumption and endurance datafor the electric ship compared to that of thebaseline CODOG ship confirmed that theelectric system is approximately 30 to 40percent more fuel efficient, offering evengreater efficiency during operations requir-ing quietness, low speed or a high state ofreadiness.

The electric propulsion frigate with cur-rent equipment designs would have to belonger than an equivalent mechanical ship.The increased weight and length would re-sult in an increased front-end cost, but thelonger ship would have better seakeepingcapabilities, require less propulsion powerand provide increased deck area to mountweapon systems.

An electrical ship design based on CoastGuard icebreaker AC/AC electrical propul-sion plant design, utilizing standard indus-trial equipment packaging is a feasiblealternative to traditional frigate designs.Potential developments to decrease the vol-ume of the electrical plant are real andachievable, and will lead to a frigate com-parable in size to the present generation ofCODOG ships.

AC electric propulsion provides a quieterASW ship with greater range capability,fuel economy through inherent cross-connect capability, optimized manoeuvra-bility by virtue of infinitely variable speedand simple rapid reversal, and improvedship survivability.

References

1. Pelly. B.R. Tliyristor Phase ControlledConverters and Cyclocowerters, J. Wiley andSons, 1971.2. DND/DMEE, German and Milne Inc.,Feasibility Electric Propulsion Stticlv, 1987.3. DND/DMEE. YARD Ltd.. Electric FrigateSimulation Stutlv. 1987.

W.A. Reinhardt is the DMEE 6 senior en-gineer for shipboard electrical motor-driveand propulsion systems.

J.R. Storey is an electrical propulsion sys-tems engineer in DMEE 6.


The Product Work Breakdown SystemBlueprint for CPF ConstructionBv LCdr Richard Pavne

Introduction

When the CPF program office firstopened its doors for business 11 years ago,the challenge was to define, solicit and pro-cure a contract with Canadian industry forthe turn-key delivery of a new fleet of Cana-dian patrol frigates. These objectives werepursued at a relentless pace, and in 1983history was made when the largest Cana-dian defence procurement contract ever wasawarded to Saint John Shipbuilding Limit-ed. Since then Saint John Ltd and its numer-ous subcontractors worldwide have joinedefforts to deliver within very stringentconstraints of cost, schedule and perfor-mance.

Significant milestones such as contractdefini t ion, contract procurement anddetailed ship design have been successful-ly accomplished, and the CPF program isnow clearly focused on actual shipconstruction. Last May during a doubleceremony at the Saint John shipyard (see"New frigates...") the "keel" section ofCPF 02 was laid in the dock, and CPF 01was floated-up and christened Halifax.Halifax's first plate of steel was cut in June1986, and in October 1989 she will beturned over to the Maritime Commanderas the first of 12 modern naval platforms.That the steel, machinery, computers andweapons can be "built" into a fully opera-tional warship in just over three years is dueto a managerial construction blueprintcalled the Product Work Breakdown Svstem,or PWBS. Conceived by a Japanese ship-builder in the 1960s, PWBS has evolved intoa widely used management tool which isparticularly suited to complex technologi-cal projects such as the construction of air-craft, nuclear power plants and warships.

The Product

The product is a state-of-the-art Cana-dian patrol frigate, fully tested and readyto fight. By using a concept called grouptechnology, PWBS breaks the product downinto manageable production objectives, or

interim products, which can be grouped intosimilar construction processes. In theconstruction of a patrol frigate some 262interim products are organized into fiveconstruction processing groups for steelunit assembly, zone outfitting, special in-stallations, modules and batch manufac-turing.

The ship has been divided into super-zones, areas of the ship divided by girth andlevel. An assembly unit is usually a singledeck-level structure, shell to shell. The CPFis divided into 58 such units which are thenjoined into 26 erection units. For example.

erection unit 2150 comprises assembly units2130, 2140 and 2150. The hull of the CPF,then, requires the processing of a total of84 units.

Once the units have been erected, workshifts to the outfit zones. Typically, theboundaries of an outfit zone are bulkheadto bulkhead and deck to deck, and can bea compartment, lobby or passageway, or anexternal area such as the fo'c's'le. In the CPFthere are a total of 111 outfit zones, eachrequiring outfitting work by various tradessuch as electrical, pipe fitting, joining andpainting.

ERECTION UNIT. This erection unit #4110 has just received a primer coat ofpaint in the blast and paint facility. The bridge superstructure is an erectionunit product resulting from the joining of assembly units 4110, 4120, 4210and 4220.

SEPTEMBER 1988 17

Some products cannot be confined to aspecific area such as a unit or zone, so mustbe processed independently as special in-stallations. These products are usually com-plicated in nature and require uniqueprocedures for their fabrication, assemblyand installation. In the CPF there are 26special installations in all, including themain shafting, the 57 mm Bofor gun, therotary vane steering system, the kingpostand the RAST gear.

There are only eight modular productsin the CPF. These items can be processedentirely off-line and then installed in theship at the appropriate stage of construction.For example, the fuel oil centrifuge anddrain tank can be fabricated, welded, as-sembled, painted and tested on the work-bench before being shipped to thewarehouse as a product ready for installa-tion in the ship.

Products having common processingcharacteristics are manufactured in batches.Swaged bulkhead panels, lighting supportsand fire-hose racks are some examples ofthe 33 manufacturing jobs used in theconstruction of the CPF.

The Work

Once a product has been dissected intomanageable production targets, the work re-quired to build it can be addressed. Shipconstruction will differ in approach fromshipyard to shipyard, depending on suchvariables as the human, technical and cap-ital resources at hand. In the Saint Johnyard, as in most modern shipyards,construction of a warship is very much anassembly line process.

The basic concepts used in shipconstruction have been around for manyyears. HMS Warrior, the world's first iron-clad, was recently restored to exacting de-tail and is now on display in Portsmouth.England. One of the less noticeable, yetsalient, features of this formidable monu-ment is that she was built, back in 1860,using certain basic principles of unitconstruction still in use today. What haschanged over the years is the refinement andimprovement, particularly in automation,of the basic processes for hull construction,zone outfitting and zone painting

HULL CONSTRUCTION. Steelconstruction involves seven d is t inc tmanufacturing levels. Part fabrication, thefirst level, produces finite componentswhich by nature cannot be further subdivid-ed. For example, flat plates of steel aremarked, cut, bent or shaped into specifiedparts. During part assembly these fabricatedbits and pieces are assembled into built-up

components, such as T- or L-shaped gird-ers, and then sub-unit assembly processesthem into structures such as deckpancls.bulkheads and shell plates.

Unit assembly involves the welding ofall sub-unit components and other assem-bled and fabricated parts into complete as-sembly units (there are 58 of them in theCPF). after which unit joining will com-bine the assembly units (two to four at atime) into the 26 erection units which willbe lowered into the dock. Hull erectionconstitutes the joining of erection units inthe dock, which eventually results in a ship'shu l l , and finally, onboard outfitting ties inall the loose ends, from back-up structureto tank testing.

ZONE OUTFITTING. This second proc-ess is subdivided into three phases: on-module outfitting is work which can be per-formed in the shop or at the workbench.on-unit outfitting involves both hot and coldpre-outfit work at the un i t stage ofconstruction when the unit is still undercover in the assembly line, and onboardoutfitting is work which can only be per-formed once the hul l has been erected.

These three different stages of outfittingare significant in terms of cost. For outfit-ting labour, a common rule of thumb is thatwhat takes one man-hour of work in the as-sembly shop is equivalent to three man-hours in the drydock and as much as sevenman-hours of work in a ship that is afloat.Sma l l wonder tha t p re -out f i t t ing isconsidered to be such a significant conceptin modern ship construction!

ZONE PAINTING. The third majorconstruction process has four categories:shop primer, primer, finish undercoat andfinish paint. The zone painting process alsocapitalizes on the practicality and cost-effectiveness of performing work as earlyas possible in the construction process.

The PWBS Matrix

Construction of the CPF involves anarmy of planners, engineers, purchasers,accuracy control technicians, qua l i tycontrol experts, cost-account managers, su-pervisors and tradesmen. These playersmust all team up in a highly coordinatedeffort to bring the CPF into being. Thegame plan for the execution of this task is

SPECIAL INSTALLATION. Shafting is one of 26 special installations in the CPF.Here a Saint John Ltd accuracy control technician prepares for the final lineof-sight measurement required to bore out the starboard intermediate A-bracket.


PRODUCT

UNITS

4410 LOWER FUNNEL

4420 UPPER FUNNEL

4410 FUNNELOUTFIT ZONES

1600 WEATHER DECK2260 PER UPTAKES3134 #2 GYRO ROOM

4114 CCR

SPECIAL INSTALLATIONS

6110 05 SONAR6230 CRUiSE DIESEL6580 MASKER BELTMODULES

7210 FEED TANK7239 AUX MACHY FLATMANUFACTURING JOBS

7609 VENTHOLE COVERS7939 FIRE HOSE RACKS

WORK CENTRE

1000

*#•*

#

**#

#

*

*

##

#•*

1100

#

*

#

*#

*

*#

*

•*

*

*#

1200

#

1300

*

1400

•*

#

*

•X-

*

1500

*#

1600

#

*

1700

*

*

•*

#

*

I

1800

*

•*

*•*

*

•*

#

-*

I

1900

*

*

*•*

*

*

*

Figure 1. The PWBS matrix represents the basic framework on which to plan,coordinate and execute all CPF construction activity. The complete matrixconsists of 262 interim products under five categories.

MANUFACTURING JOB. Cable hangers utilized throughout the ship aremanufactured in batches. The items are then kitted by unit for installation atthe hot pre-outfit stage of construction.

the matrix of the product work breakdownsystem. As previously outlined, the prod-uct has been carefully analyzed and sub-div ided into 262 interim products.Furthermore, the work required to build andassemble these 262 products has been as-sessed and delegated to ten well-definedwork centres. These two elements, prod-uct and work, now form the basic frame-work of the PWBS matrix. Figure 1represents a sampling of the matrix, whichin its entirety consists of the 262 interimproducts versus the ten work centres.

Each intersection of product and workcentre constitutes a 'cell' of activity, or ajob. These jobs in turn signify various re-quirements to the different participants inthe construction activity.

Planners will use the PWBS matrixprimarily as a scheduling tool. Their ob-jective is to determine start and finish datesfor each job, and to coordinate the workin order to achieve an efficient productionrun with a relatively constant workforce.When at full production, CPF constructionactivity at Saint John Shipbuilding will re-quire a workforce of approximately 1200tradesmen. The planning department is alsoresponsible for promulgating the necessarywork orders, depending on the number oftrades involved and the scope of work re-quired to accomplish the task.

The engineering department also usesthe matrix, primarily as a schedule for thedevelopment and issue of production draw-ings, but also as a guideline for the promul-gat ion of unique procedures. Fieldengineers must also possess a workingknowledge of the PWBS.

The material purchasing group uses thePWBS matrix extensively. Their respon-sibility is to procure the right material atthe right time, thereby feeding constructionactivity without interruption while main-taining the warehouse at a manageable andcost-effective stock level. The CPF requiresan endless amount of logistical support,from nuts and bolts to sophisticated weap-on installations. The ideal procurement planfor this type of project calls for an item tobe on hand eight weeks prior to it beingrequired at the first work centre.

The Quality Assurance Manager canalso benefit enormously from the PWBSmatrix. The matrix provides the frameworkon which to formulate the master inspec-tion and test plan (ITP). For example, anITP can now be developed for each prod-uct at each work centre. This ITP will in-clude receiving inspections, in-processinspections, accuracy control and NDE re-

SEPTEMBER 1988 19

quirements, and the all-important final in-spection prior to releasing the product tothe next work centre. Many of the jobs arerepetitive processes for which a commonITP can be developed. Therefore, the taskof designing an integrated master ITP forthe CPF construction program becomes arelatively easy assignment.

To the senior managers the PWBSmatrix becomes an invaluable yardstick formeasuring production, cost and scheduleperformance. Each activity cell representsa finite amount of the budget and thereforehas a weighted value in comparison to thewhole project. Consequently, a true meas-ure of physical progress and man-hour costscan be determined as the various interimproducts are completed in each work centre.

Conclusion

A technological task such as theconstruction of a Canadian patrol frigatedemands the expertise, and more impor-tantly the cooperation, of a variety of tal-ent. Not only must the ship be built tospecification, but the job must be accom-plished within the ever-present constraintsof cost and schedule. The PWBS matrixprovides the framework on which this com-plicated task can be successfully complet-ed. The Product Work Breakdown Systemitself provides the common language neces-sary for its success.

LCdr Richard Payne recently served forthree years in Saint John, first as theAnnapol is DELEX refit project officer andsubsequently as the marine systems quali-ty assurance officer in the CPF leadyarddetachment. He is currently attending theCanadian Forces Command and Staff Col-lege in Toronto.

WORK CENTRE 1400. This is the work centre where flat and curved sub-unitcomponents are assembled into assembly units. The assembly units alsoundergo hot pre-outfit work here. The bow section seen at the far end of thework centre is assembly unit 1150.

DRYDOCK. Approximately one quarter of all work required to construct aCPF takes place in this work centre. Here, erection unit 1250 is lowered intoposition.


New frigatesa shipbuilding success story

By LCdr Brian McCulloughJournal production editor

The Canadian navy was ceremoni-ously launched into the 21st century inSaint John, New Brunswick last Maywith the "float-up" and christening ofHMCS Halifax, lead ship of the 12 newpatrol frigates promised to the navy, andthe "placing in the dock" of the firstmodular unit of CPF 02 - the futureHMCS Vancouver.

Thanks to the unit construction of thenew frigates, gone were the more tradi-tional methods for launching down theways and laying a keel, but in their placewas the remarkable evidence of a ship-building success story.

On the day the newly named Halifaxwas towed out of the Saint John Ship-building drydock and secured alongsidethe wall to complete her fitting-out, theship was 55 percent complete. That, saysome, is the highest percentage comple-tion at launch for a lead ship of any navalcombatant construction program in theWest.

With the champagne still wet on herbows, all of Halifax's welding and mainhull-steel painting was complete, she wasinsulated throughout, the main genera-tors, main engines, gearbox and shaft-ing were installed and compartmentcompletion below the third deck hadbegun — all barely 14 months since herfirst pre-outfitted unit was lowered intothe dock.

To get a better idea of the extensive-ness of the pre-outfitting being used inthe frigate construction process,consider this. Moments before Halifaxwas christened the first erection unit ofthe future Vancouver was lowered intoan adjacent drydock. As the 50-tonneunit came to rest on the blocks andDefence Minister Perrin Beatty declaredthe keel of CPF 02 "well and truly laid",five more pre-outfitted erection units satoff to one side ready to be joined to thefirst. The vessel was already 21 percentcomplete.

There is no question that the shipyardis benefitting from the constructionlearning curve. The erection units for 02are being more fully pre-outfitted thanwere the 01 units, and the degree of pre-outfit work on the follow-on ship(Toronto, now in the fabrication/assem-bly process) will be even greater.

According to Shipbuilding DirectorMatt Reid the second vessel is muchfarther advanced in terms of pre-outfitting than was CPF 01 at the samepoint in the schedule. By May, 33 of the57 assembly units had been completelyassembled, fabrication was 85 percentcomplete and seven of the 26 erectionunits had been completed and painted."We are about one month ahead ofschedule on CPF 02." Reid said. Float-up is scheduled for March of next year.

"/ name you HMCS Halifax.God bless this ship and allwho sail on her." — MilaMulroney

SEPTEMBER 1988 21

Software and the MAREBy Cdr Roger Cyr

Presented at the MARE Seminarin Ottawa, 20 April 1988

Introduction

Computers have found applications inmost modern systems. They guide torpe-does and missiles, tune radios, track andevaluate targets, and control propulsion ma-chinery. Embedded computers have becomea critical component of all shipboard sys-tems, with their power stemming from theirflexibility, via software, to readily adapt sys-tems to changing requirements. However,experience has shown that software is costlyto produce and difficult to control. Thereis no question that software has contributedto the realization of military systems of un-paralleled sophistication and potential, butthis software revolution has unfortunatelycome accompanied by its own peculiar andgrowing problems — problems which af-fect all systems, and as such have becomethe purview of all MARE officers.

Background

The Canadian navy entered the age ofAutomatic Data Processing with the arrivalof the DDH-280 Tribal class destroyers inthe 1970s. With these ships came the na-vy's first command and control computers,and the navy's first encounter with softwareand its associated problems. Programmingfor the system was for the most part relegat-ed to a few naval officers who started cod-ing after taking a short course inprogramming. As a result, the software washighly unreliable and program crashes oc-curred frequently; a situation whichcontinued to exist ten years after the sys-tem was brought into service. When thesecatastrophic failures occurred, the Tribalsbecame virtually disabled and were easyprey to any attacking unit.

Systems of the '90s

The ships of the '90s, the Canadian Pa-trol Frigate and the upgraded Tribal classdestroyers, represent considerable techno-logical advance with respect to computerpower. In the CPF virtually all systems andsubsystems (including propulsion machin-ery subsystems) will rely on fully integrat-

1.0

0.8

0.6

0.4

0.2

SOFTWAREIMPACT

1950 1960 1970 1980 1990 2000

Fig.1. The Relative Influence of Softwareon System Design and Development

THE SOFTWAREICEBERG

APPLICATIONSPROGRAMS

HOST COMPUTER(S) OPERATING SYSTEM

LANGUAGE TRANSLATORS PROGRAM EDITORS TEST TOOLS

PROGRAM LINKERS SYSTEM SIMULATORS DESIGN TOOLS

I ENVIRONMENT^ SIMULATORS

PROGRAM DESCRIPTIONDOCUMENTATION

I DIAGNOSTIC SOFTWARE USERS MANUALS

CONFIGURATION MANAGEMENT )PROCEDURES ^

TEST PLANS FLOW CHARTERS V

DEVELOPMENT TOOLS TEST DRIVERS DEVELOPMENT STANDARDS I PERSONNEL

PROGRAM DESIGN DOCUMENTS INTERFACE DOCUMENTS TRAINING

Fig.2 The Software Iceberg


ed embedded computers for dataprocessing. This is advancement, to be sure,but at a price. For with these myriad embed-ded computers which are about to enterservice comes an extremely large softwareinventory, one which will requireconsiderable attention from the MAREcommunity in the years ahead.

The Software Crisis

Software has become the dominant com-ponent of modern systems and subsystems(Fig.f) because of the integration functionit performs. In some cases it has actuallydictated both the system and its architec-ture. It is important to note that softwaredoes not consist only of applications oroperational programs. Far from it. Appli-cation software normally comprises onlyabout ten percent of the total software ina system (Fig. 2).

Software requirements for embeddedcomputers are growing at an alarming rate.But where technological developments havekept hardware costs down, the costs for soft-ware have skyrocketed. In 1980 alone theU.S. military spent $4 billion on embed-ded computer resources, 65 percent ofwhich was taken up by software (Fig.3). For1990. of the $38 billion planned to be spenton embedded systems, the portion allocat-ed to software will increase to 85 percent.

The U.S. Department of Defense nowestimates that the number of embeddedcomputers in use by 1990 will reach 250,000from the 10.000 in 1980 — a 25 times in-crease that is being accompanied by sig-nificant perturbations. Recent rules ofthumb for estimating software costs indi-

cate that, whereas the total cost per line ofdelivered code in 1975 was $75, today eachline of code is estimated at costing closeto $200 to develop and $4 000 to maintainover a ten-year life cycle. But what is evenmore alarming is that even at these costsflawed code in mission-critical systems isthe norm rather than the exception. TheU.S. National Bureau of Standards esti-mates that delivered software for large sys-tems typically has errors (which affectsystem performance) at a rate of one in ev-ery 300 program statements, or 3.3 errorsper 1 000 lines of source code.

The problems of high software productcosts and low software reliability are stillvery much with us. This is not a failing inthe development of software engineeringideas, but a reflection of the fact that im-provements in software production technol-ogy have been unable to keep pace with therapidly increasing demand for complexsoftware products.'

A recent study estimates that the demandfor new software is increasing at a rate of12 percent, but that the growth in program-mer productivity is growing by only fourpercent annually. Moreover, in 1985, theElectronic Industries Association calculatedthat the shortage of programmers in NorthAmerica (then estimated at 100 000) couldreach one million by the early 1990s. Thisnumber did not take into account such mas-sive development projects as the StrategicDefense Initiative (SDI), which is expect-ed to require programming services of un-precedented size and complexity. There areeven fears that the major stumbling blockto SDI will be the lack of personnel

1980 $4,100M

Fig.3 Embedded Computers — Hardware vs. Software

resources to complete the software pro-gram, which is estimated at 25 million linesof code.

Canadian Naval Software

With the advent of CPF and TRUMP thesoftware support requirements of the Cana-dian navy will grow to about a million linesof code. This means that a great propor-tion of the navy's limited personnelresources will have to be directly employedon in-house software maintenance asprogrammers, analysts and software en-gineers. In addition, since all systems willrely on embedded software, every MAREinvolved in system management will haveto be "software literate."

Based on the National Bureau of Stan-dards average, the number of errors remain-ing after a real-time system such as CPFbecomes operational could be around 3 000.And these would be catastrophic errors af-fecting performance. When we apply therule of thumb regarding the maintenancecost per line of software, the navy likelyfaces a $4 billion bill for embedded soft-ware support in the years ahead. This is theestimated labour cost for the life-cyclemaintenance of CPF and TRUMP software.

Future Software Support

Mission-critical systems must be main-tained regardless of the cost and volume ofthe activity. Since software has become thedominant element of most systems, the re-quirement to possess software skills will nolonger be the domain of a few officers em-ployed directly in software maintenancetasks. It will be the concern of all who areinvolved with systems, be it designing, im-plementing or maintaining them. Systemdesigners, for example, will have toconsider such issues as whether more hard-ware may modify the need for software, thepotential trade-offs between hardware andsoftware and the interfacing requirementsbetween hardware and software.

The U.S. Defense Science Board taskforce on military software concluded thattoday's major problems with software de-velopment are not technical, but stem ratherfrom managerial shortcomings. Anotherauthority, the Software ProductivityConsortium representing the 14 major aer-ospace industry corporations in America,argues that the problems stem from the useof the traditional software managementmodel — the so-called waterfall model(Fig.4) which calls for formal specification,design, coding and maintenance phases.The consortium states that this document-driven approach may not be ideally suitedfor embedded systems, and that an evolu-

SEPTEMBER 1988 23

SOFTWARE PROBLEMS STEM FROM THEUSE OF THE STANDARD WATERFALL MODEL

-SOFTWARE PRODUCTIVITY CONSORTIUM

REQUIREMENTS

DESIGN

CODE

INTEGRATION

MAINTENANCE

Fig.4. The Waterfall Model for Software Management

tionary model (Fig.5) should be adopted topermit incremental software development,using prototyping and design iterations inan overall system perspective.

Given the nature of naval requirements,embedded software is redeveloped severaltimes after the initial version is delivered.With the development process shown inFigure 5, redevelopment is carried outthroughout the lite cycle of the system. Thepoint of reentry for redevelopment is de-termined by the scope and magnitude of theintended change. It is then determined ifa complete or partial rebuild is needed. Itis now considered cost-effective to adopta philosophy of discarding prototype soft-ware, as is done with prototype hardware.

Industry experience has shown that de-spite the use of traditional system develop-ment methods, users of the system regardthe resulting applications as neither correctnor complete. This occurs because thetraditional methods were unable to ac-curately capture the user's true needs.

Ada Language

Software has been described as too ex-pensive, always behind schedule, neverworking according to the specifications and

GENERIC SYSTEM DEVELOPMENT PROCESS

INITIALSYSTEM

DEVELOPMENTVERSION

2VERSION

3 • ••VERSION

N • ••

^/HARDWARE DEVELOPMENT

Fig.5. The Evolutionary Model


impossible to modify. These attributes de-fine the software crisis which led the U.S.defense department to fund development ofthe Ada language. Language proliferationwas a major cause of their software difficul-ties, and it was found that over 450 differ-ent computer languages were being usedfor mission-critical systems, with none ofthe languages dominating the others as faras frequency of use was concerned.

Other than providing the single commonlanguage. Ada's major advantage is inproviding the means to achieve the benefitsof modern software engineering methods.A key element in the Ada concept is theexistence of a complete Ada programmingsupport environment comprising all thetools required for the production of embed-ded systems. Ada has been mandated as thesingle, high-order language in the UnitedStates* and NATO, and in Canada a recentpolicy directive established Ada as the man-datory language for capital projects.

Early experience with Ada suggests thatthe promise of increased software produc-tivity and reliability wi l l be fulfilled. How-ever, many problems remain, such as theneed for validated and efficient compilerstargeted to embedded systems, and softwaredevelopment environments built aroundAda. The technology supporting Ada isevolving rapidly and validated compilers for

* The U.S. DOD spent $700 million in 1987 onsoftware written in Ada. and it is expected thata further S16 billion wil l he spent on Ada by1990.

embedded systems are now emerging in themarketplace.

The use of Ada alone will not guaranteethe generation of better software. Good,modern principles of software engineeringare needed for software design, and Adawill enforce those principles better than anyother language.

Software in the Future

In the years ahead systems will make useof supercomputers, consisting of a largenumber of parallel processing systems com-posed of clusters of processors dedicatedto activities such as artificial intelligence,number crunching, graphics or databasemanipulat ion. These super-knowledge-based systems wil l have memory space ofhundreds or thousands of gigabytes, data-transfer rates of tens of gigabytes per se-cond and large software programs capableof processing data with incredible speed andaccuracy. With these supersystcms it ishoped that vast improvements in the waywe produce software will be forthcoming.

In this era of automated mass produc-tion of chips, memory and other hardwareelements, it is totally incongruous that theart of programming will remain unchangedfrom its earliest days. It is expected that in-dustrialized programming — the "softwarefactory" — will emerge. Just as hardwaresystems are assembled with standard boardsand circuits, so the software program fornaval systems of the future will likely beassembled from standard software compo-nents which have been recycled from othersystems or procured from off the shelf.

Conclusion

It has become quite fashionable to com-plain about software and the processes andorganizations that produce it. The problemsof software continue to manifest themselves,and their effect is growing as systems be-come more complex and more dependenton software. The software process isdif f icul t to control, estimate, schedule ortrack. It is both a technical and managerialproblem. Since all systems now depend onembedded processors and software, it be-hooves all M AREs to become proficient instructured software/development metho-dologies if the software crisis is to beconquered.

Commander Cyr is the DMCS 8 .sectionhead for naval computer technologv atNDHQ.

Panic!On the spur of the moment, the Naval Overseer for Assiniboin&s Montreal refit, a

Chief Hull Tech, decided to check the cleaning of #1 ballast tank. Entering the tankalone and not noticing the hose lines hanging from the manhole, he crawled to the for-ward end of the tank, a very tight fit. To his horror, the tank started to fill with water.Panic-stricken and unable to dislodge himself from between frames, he screamed forhelp. With luck, the tank tester understood his scratchy Scottish accent, shut off thewater and the rescue began. With the aid of one Pusser, two haulers and a charge hand,the Contractor managed to extricate him from the tank ... but not his predicament. Hewas later presented with a (hoax) Form 1379 Bill of Arisings totalling $2500 for "theremoval of Naval Overseer from tank."

Ed McSweeney, Senior Hull Inspector,NEU(A)

Do you have an amusing anecdote?See page 1 for our address

SEPTEMBER 1988 25

Looking Back: 1986The Nipigon Bow FractureBv Cdr John Edkins, Naval ArchitectureOfficer, NEVALt(N) Mark Gray, Ships and SubmarineServices Officer, NEVAMr. Clvde Noseworthv, Chief Hull Inspec-tor, NEVA

Editor's Note — When cracks were discov-ered in Nipigon's stem back in 1986 therewas little hard evidence to indicate what hadcaused them. A certain amount of conjec-ture was made at the time, but nothingdefinitive was ever put forward to explainthe probable cause of the damage. Untilnow. When these photographs by chanceresurfaced at NEU(A) last spring, theysparked a renewed interest in the problem.With the help of the photos, the authors felta hypothesis could be made which wouldexplain the stem structure failure in Nipi-gon and in other steamers where similart\pe damage has been occurring since themid-1970s.

We all know that our ships take a pound-ing out in the Atlantic. Probably the mostvisible and disturbing sign of the wear andtear they endure is the presence of cracks.In the spring of 1986 ship's divers discov-ered extensive hull damage in the forefootand stem sections of HMCS Nipigon. Theopening (Fig.l.) permitted flooding in theforepeak and significantly reduced thestructural rigidity in this area. Further evi-dence of the problem was illustrated bymore cracking observed in the plating over

several transverse and longi tudinalstiffeners in the lower bow area.

To prevent further damage to the shipwhile she fulfilled her operational commit-ments, interim repairs were made in April1986 by FDU(A) alongside in Halifax. Theopening was closed using bolts and flat bars,and the cracks were arrested by drilling outthe ends (Fig. 2.) A month later, Nipigonwas docked and the entire stem assemblywas rebuilt (Fig.3.).


In an attempt to determine the cause ofthe problem the DREA Dockyard Lab wasasked to analyze the damage. Unfortunate-ly, the crack "history" had been erased bycorrosion and by the stop-gap repairs. It is,however, still possible to hypothesize a fail-ure mechanism and possible causes basedon the clearly visible evidence.

The propagation of the cracks along thestem bar is largely confined to the weldbeads (Fig.L). suggesting that the crackgrowth was controlled by material charac-teristics within the heat-affected zone. Thecracks may have been started by long-termcorrosion in the inaccessible forepeak voidspace, or by a defective weld, but it is fair-ly certain that a large force would have beenrequired to open the hull .

Since there was no evidence of collisionor docking damage it is felt that the dam-age was caused by slamming. The stemstructure in our steamers is extremelyslender and flexible, and thus it is very like-ly that the structural damage in Nipigon wasdue to fatigue failure under repeated flex-ing of the stem.

Given the age of these ships, their oper-ating conditions and their stem and fore-foot design, this type of failure will likelycontinue to occur. (A longitudinal crack dis-covered in Margaree's forefoot this year maywell have been the start of such a problem.)However, awareness of the situation shouldresult in early recognition of the problemand a concomitant reduction in repair time.

Fig.2.

Fig.3.

SEPTEMBER 1988 27

News BriefsBravo Zulu

Congratulations go out to CommanderPeter McMillan and Lieutenant Com-mander Brian Staples. Their article "SaintJohn Shipbuilding Ltd and CPF Construc-tion", which appeared in the January 1987issue of the Journal, was recently selectedas background reading to the CanadianStudies program at National Defence Col-lege in Kingston.

Sonar production contractawarded

Computing Devices Company of Nepean,Ontario has been awarded a $21.3-millioncontract for the production of AN/SQS-510sonar equipment for the Canadian andPortuguese navies.

Under the terms of a contract let lastApril. Computing Devices will furnish twosets for HMC ships Nipigon and Annapo-lis, and a further three sets for Portugal aspart of a NATO military assistance programto that country.

Nipigon should receive the AN/SQS-510late in 1989 and delivery to Annapolis isexpected to follow a year later.

The first delivery to Portugal is sched-uled for March 1990. The 510 sonar willbecome the primary underwater sensor onthree MEKO-200 anti-submarine frigatesnow under construction in West Germany.

TRUMP officers receive awardsLCdr Alex Rueben and Lt(N) Noel

Purcell, both of whom were employed inthe TRUMP PMO from 1986 until thissummer, have received awards for excel-lence from the Canadian Institute of Ma-rine Engineers.

LCdr Rueben was honoured for achiev-ing the highest mark in the naval engineer-ing certificate of competency (marine

systems) Part I exam for 1982, and for thehighest mark in the Part II exam for 1985.

Lt Purcell was honoured for achievingthe highest mark in the combat systems Cof C Part II exam for 1985.

The awards were made in Ottawa lastApril 26.

Bravo Zulu to both officers!

Pictured at the awards ceremony are TRUMP Project Manager Capt(N) R. Preston,Lt Purcell, LCdr Rueben and C.I. Mar E. Ottawa Branch Chairman Gerry Lanigan.(TV. Martin photo)

CANTASS.Coming up in ourJanuary issue

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