panel m-8 special ca.gas trials guide for.jul.1977.t-r

7/28/2019 Panel M-8 Special CA.gas Trials Guide for.jul.1977.T-R

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~ Technical md Research Bulletin 5-2

GAS TRWS WIDE FORL~G ~ssELs

Prepared byPANEL M- 8 (SPECM MGO Sys=)

of theWIti SYS=S C_TTSE

~blished by~ SOCIE~ OF NAV& ARCHITE~S ~ NARINE EffiI~RStie World Tmde Center, Stite 1369Nw Yo:~yNi;j7100@

Cop~+ght 1977 by.me Society of Naval kchitects and Wrine Engineers


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This Bulletin has ken Prepared byPAwEL MS-8 (SPECIAL CARGO SYSTEMS~

ofTHE SOCI~ OF NAVAL ARCHITECTS AND ~1~ ENGIWEEX

TECHWICAL AKD =SEARCH PR~Capt. ~ilip J. ~nahy, =CG, ~air~nMchibld G. Gillies, chair-n,

Task WOUp - LWG Trials Guide

Bertrand de Frondeville&rard F. EustaCeJames L. HmardStavros xaratzaaDOuglas C. mcMillanRonald J. McAlear&axles F. MooreJmes L. MOSSW. Taylor %tterW. K. B. Wtts

Carl L. RitterS. T. mbinsonVictor R. SchellenbergH. Frank ShawDale A. Stith .~pt. G. C. Stei_n, USCG (Ret.)Willim DuBarry ~omas~mmd G. mrnaySd-rd UttridgeR. C. Van Meertike

andMARINE SYSTEM COMW1~E

Capt. William M. Nicholson, USN (Ret.), ChairmanCapt. Ri~ards T. Miller, USN (Ret.), Past ~air~n

Henry A. WnoldJohn R. BaylisDonald P. CourtsalWilliam A. ~eehanPhilip J. ~nahyWilfred J. EggtigtonFhillip EisetiergDavid L. FolsaWilliam H. @rmanJames G. Grossroof. s. R. Heller, Jr.James A. HigginsHarry A. JacksonDr. Robert S. JOtisOntilyn L. JonesEdward S. KarlSon

Raymond KaUfianDr. ROtirt KayWillim T. LindemutiRofirt S. LittleEdward M. NcCut&eonAlan C. tiCIUXeWalter H. tichelkrry J: OISOnJoh A. witzlaffDr. Joti c. PurcupilePeter G. RatieyW. F. Searle, Jr.Blakely SmithHe~y M. TiedmannRichard P. VoelkerDr. Uskar Wechsler

~evOX &wis-Jones, Assistant Secretary fOrTechnics 1 and Ptilications


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PASFACE

The increased worldwide interest in utilizing~G and moving LNG in bulk shi~ents by water hasresulted in extensive ship construction activitiesfor this specialized cargo. The Marine sYst~scomittee had tasked its.SPecial car90es sYst~sPanel to detemine if and how. the Society of NavalArchitects and Marine Engineers could contribute tothese efforts. Inquiries tO VariOus Se~entS Of themarine industry identified tie usefulness andneedfor a s~cial, addition to the SN* Codes C0verln9the Etiject of Gas Trials.A group Of experts was assefiied representingknowledge and experience spanning a variety of de-signs, vessel operations, and shipbuilding yards aswell asextending back in.time to the first LNG ship

the ~T~E PIO~ER. Considering the innovativenatur,eof past and present LNG vessel cOntai~entsystems and the related supporting systems it is tObe expected that in the near future new des i9ns iiibe proposed and developed which .wi11 necessitateadditions or modifications toupdate. ~is Guide.Therefore, criticism in the fom of recotiendationq,and ,suggestions are expected and invited so that:::h::iate addenda may be published in a t~~lY

The Guide is advisory On.ly, and ~ere is nOimplication of warranty by tie Society that success-ful perfotiance of tie recommended trials will ensurethat ,a ship wi 11 comply with the re~irements of thecontract specifications,, re~latory bodies or classi-fication societies, or that .it will perfomsatisfactorily and safely in se~ice.The Panel gratefully acknowledges the con-tributions of the metiers of the Society, industiy,and goverment who have been generous in assistingthe Panel in accomplishing its task. The Panel alSOthanks the Society 1s Technical AtiinistratOr andhis staff for the cheerful and timely services.iifacilitating and coordinating the execution of itsassigment.

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TABLE OF cONTENTS

ABSTWCTPRSFACE1NTRODUCTIONSECTIONS1.0 ......................PRSTXIAL PREPARATIONS

2.0 ......................DRYING AND INERTING3.0 ......................COLD TESTING OF DECKNACHINERY AND PiPING4.0 ......................DISPLACE~NT OF INERTGAS AND COOL-DONN5.0 ......................LNG HANDLING6.0 ......................BOIL-OFF mDLING7.0 ,?ARNUP AND GAS FAEEING......................E.O ......................FIRsT uLL LoAD ANDDISCHARGE9.0 ......................GLOSSARY OF TEMS

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informationGas Trials for

~ST~CT

This Guide nrOvides definitive...on the preparation for and conduct ofmG vessels. Such trials are intended to prove thesafe and adequate operation of all systems and theircomponents involved with or pertaining to the ship-board handling, stwage, disposal, etc. of LNG,particularly those systems and cmponents not other-wise covered by other codes. It is meant to be acomprehensive guide covering all varieties ofcontainment system designs and tierefore m=st beused with the caution that all itms contained withinthe Guide may not be fully pertinent to a particulardesign.

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ORIGINThis Guide was developed by apanel composed or representatives ofherican shipbuilders, ship owners,and operators, the Maritime A*inistra-tion, the ~ericafi Bureau of Shipping,the U. S. Coast Guard and other expertsin the LNG industv under the auspi CeSof the xarine Systems comittee, of theSNME . Publications of other SN~Technical Panels were consulted tocheck compatibility.

PURPOSEThe purpose of tie Guide is toprovide ship o~ers, designdrs, opera-

tors and builders with definitiveinformation on LNG trials to fom abasis for contractual agreement.Ncthing in the Guide should beconstrued to delete or modify require-ments of s~cified regulatory bodies.

TRIAL OBJECTIVESm LNG trial may have one O.Xmoreof the following objectives dependingon the position of the ship in.itsclass, the imovative content of itsdesign, md the needs or desires of its-ers.a. DEMONSTRATION OF OPERABILITY

LNG Systms can be shm toOPrate in their design modes only henthese systms are at their operatingtaperature, pressme, etc. and theshipbuilder and wrier both benefit froma demonstration of proper operationwhich shins tie correctness of con-s~ction, mmufacture and installation.

b. D~ONST~TION OF PERFOMCELNG trials should be perfomedmder conditions which most closelyduplicate operating conditions to Pr-

tit pro~r assessment of performancedata.

c. PROVISION OF OPE~TING DATAIt is desirable to establisha data baseline for any new class ofships and to a lesser degree for in-dividual ships so that ship operatorswi 11 have a standard to which to comparecurrent operating data, entiling thato monitor performance.

d. PROVISION OF FOWNSIC DATAIt is increasingly importantfor ship operators to have availablecertifiable data on the ships capa-bilities in the event the ship isinvolved in legal action.

e. PROVISION OF DESIGN DATAAll LNG trial data auwentsthe bank of design data on which navalarchitects and marine engineers draw,but special data to verify the swcessof an innovative feature or to advancethe state of the shipbuilding art may becalled for. In such cases it is impor-tant that tie design authorities whowill use the data specify requirementsin detail, including instrumentation,operating conditions, and procedures.

f. CLASS IFICATION AND SAFETYEQUIRE~NTSClassification societies andregulatory bodies often require demon-stration of equipments and systemswhich affect safety of the ship, itscargo or its crew.

SELECTIVE INVOCATIONBlanket invocation of the Guide isnot intended. Sufficient test andtrials are included to entile the userto select appropriate trials as desired,but invocation of the total Guide with-out regard to the objectives to beserved or the utility of data obtainedwould result in costs possibly incom-

mensurate with value. Users shouldstudy the Guide and specify by ntier

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in the ship?s specifications the para-graphs covering the trials and testsrequired to meet their objectives.The Guide recognizes the workproduced by lMCO (the IntergovernmentalMaritime Consultative Organization) ,primarily IMCO Assetily ResolutionA 328 (IX), (Novetier 1975), code forConstruction and EquiWent of VesselsCarrying Liquefied Gases in Bulk.This ~CO docment refers only to newships :

=COGNITION OF UNCERTAINTYAlthough ship designers, builders,and trial personnel may exercise thegreatest diligence in pursuing theirarts at their most advanced state,there is inherent in the mensurationof ship performance an unavoidtileuncertainty. No measurement is per-fect and shipboard conditions precludethe use of the most precise techniques.Since the major ship perfomaxce para-meters involve measurement 0? manyfluctuating quantities, each with anelement of uncertainty, the emulativeeffeet might be considerable. BY

aPPlYin9 probability techniques to thedegree of fluctuation and tie inherentprecision of the instruments involved,including their calibration, it ispossible to identify the degree ofcertainty with which a ships perfor-mance can be detemined. It isimportant fiat all parties to a shipconstruction program recognize theuncertainty of trial results and takeit into consideration when esttilishingperformance target/bonus/penaltylevels.

Knowledge of how and hw much theprecision of the individual measure-ments affects the performancedetermination and the range of pre-cision available for the instrumentsinvolved enables the trial planner tomake an intelligent and economicdecision on instrumentation .P~NING

From award of a contract untildelivery of the official trial report,LNG trials require planning. Trialinstrumentation requirements must beincorporated in design; prearrange-ments may be required for obtainingand calibrating trial instrwents;trial readiness checks must be includedin production planning: trial dataacquisition, processing, and reportingsystems must be developed, installedand checked: instructions and pro-cedures must be developed for trialoperating and data crews, and thesecrews must be trained.

These actions have an Optimm timeof accomplishment beyond which there isadded expense and disruption.

A prerequisite to all planning iSa clear understanding as to the testsand trials to be conducted, the depthof instrumentation and the data to bereported. If this Guide is properlycited in the ships specifications,requirements should be clear, but ifthe Guide is not cited or there remainsan area of dotit, the shipbuilder,omer and goverment authorities (ifinvolved) should reach agreement assoon as possible after awarC, using theGuide ss a basis for understanding.Presming that agreement has beenreached, the actions outlined below cenbe taken as applicable.

PW-TRIAL CHECK LISTS0 many items are involved indetermining readiness for sea that itis virtually necessary to use a checklist. Such a list would include thefollowing as applicable:a. OPERABILITY CHECK-OFF

A list of ships machineg tobe used on the trial should be preparedand operability of each item est~lish-ed and checked off.b. INSTRU~NT INSTALLATION ANDCALIB=.TION

Instrwents to be used fortrial data shouid be listed, inspectedfor damage and checked for proper in-stallation, and availability ofcalibration data, and red hand set-tings should be detemined.c. DOCU~NT CHECK

The followin? items, preparedin advance and avail~le for the trialsmay be helpful.(1)

(2)

(3)

(4)

(5)(61

Data systems operatinginstructions.Data fores and calculatlOnfores .Instrwent calibrationrecords and correctionfactors.Correction factors fornon-standard conditions.Data crew instructions.Trial aqenda, Proceduresand scll>dule.s.

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(7) Selected drawinqs anddiagras.d. CO~UNICATIONS SYSTEM OPE~-BILITY

A pre-departure check shouldbe made of the communications systemto be used, including all stations.BuILDERS TRIALS

If builders trials or runs are tobe conducted, they should be specified.Tf datafor any portion of the trialsor runs is to be presented for accep-tance, the owners, acceptanceauthorities, and regulatory bodies(if involved) should be notified inadvance. If builders trials are notspecified, they are to be at the dis-cretion of the builder for any purpose,including any of the following:a. Checking the o~ration ofinstallations and the trial equipment.b. Training tieoperating and

trial personnel.c. Making adjustients to estab-lish proper operation.d. Determination of ability tomeet performance requirements.

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1.0 PRSTRT~ PRBP~TIONS1.1 The Trials and Tests des-cribed in this section shall becompleted prior to introduction of LNGinto the vessel.1.1.1 Tanks

(a) Tanks shall bestrength and leak tested as specifiedby Classification Society, Regulatovand Contractual requirements.1.1.2 After testing, the tanksshall be stistantially dried, visuallychecked for ex,idenceof overstress ordistortion, carefully searched forforeigrimatter, cleaned and then thetanks closed.1.1.3 If built and tested

independent of the hull and installedaboard intact, the tanks shall bevisually examined internally, exter-nally, or internally and externally (asappropriate to the tank design) forsigns of distortion or distress afterinstallation.

1.2 Piping Systems1.2.1 Fiping Sti-assefilies shallbe strength and leak tested in accor-dance with Regulatory and Contractualrequirements.1.2.2 Installed piping shall beleak tested prior to insulation of

field joints, in accordance withRegulatory and Contractual require-ments.1.3 g1.3.1 Pwps and motors shall beadequately protected from moisture andother contaminants during shipment andstorage at shipyard and during holdingperiod after installation in tanks.Motor heating circuits, desiccantpackaging, conditioned storage, or acofiination of these methods may beemployed.1.3.2 Proper direction of rOta-

tion shall be demonstrated, wherepossible, after Preps are electricallyconnected.

1.3.3 Freedom of rotation shallbe daonstrated, where possible, justprior to final closing of tanks.1.3.4 Electrical insulationresistance tests should be perfomedperiodically during.all storage andidle perids and shall be perfomedjust prior to final closing of thetanks, and just prior to introductionof LIJG,and the results recorded andcompared.1.4 Cargo Equipment1.4.1 All. temperature and levelsensing syst-ms shall be tested asagreed and to the satisfaction ofRegulatory Body and Contractual require-ments , Circuit continuity shall beDemonstrated.1.4.2 Gas detection equipmentshaIl be tested as agreed and to thesatisfaction of Regulatory Body andContractual requirements. In the caseof smple-draw systems , all lines shallbe proven clear and capable of drawin?samples.1.4.3 The simulated output ofall pressure tem?era.ture and levelsensors shall be temporarily connectedto associated slam and shutdowncircuits to check operating safeguards,including slams, pmp shutdowns, andremote valve operations.1.4.4 In addition to tests atpoint of manufacture, cryogenic deckmachinery shall be tested in accordancewith the requirements of Section 3hereof.1.4.5 tiere electrical groundingconnections are required between cargotanks and hull, and cargo handling com-~nents and hull, these should be

checked for integrity prior to anyoperation.

1.5 Prerequisites to Cold Trials1.5.1 Conventional sea trialsshall have been comuleted in accordancewith S= Code for.Sea Trials to theextent required by thetiact docwents. appropriate cOn-


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1.5.2 The vessel shall have beenaccepted by Classification Society andRegulatory Bodies, to the fullest ex-tent possible, prior to satisfactorycompletion of Cold Tests and Gas Trials.1.5.3 A complete agenda shallhave been prepared and agreed to forthe Gas Trials.1.5.4 The test agenda shall havebeen approved by all cognizantauthorities, including those agencieshaving jurisdiction in the port orports to be used during the ColdTests and Gas Trials.1.5.5 The time and place ofliquid availability and the amount ofliquid to be made available should bedetemined. These factors shall beused to detemine the details of theCold Tests and Gas Trials.1.5.6 The capabilities of theloading teminal with.respect topwping rates, return of gas toshore, duration of availability, andall restrictions and limitations

whether of regulatory or operationalnature shall have been fully deter-mined.1 .5.7 Arrange for ship-to-shoreconnections and comunica tions.

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2.0 DRYING AND I~RTING2.1 Inert Gas Plant2.1.1 The inert gas plantinstallation (if fitted) shall betested to daonstra te satisfactoryoperation and to verify rated per-formance.2.1.2 The performance teSt maybe conducted on a prototype or thefirst unit at the manufacturersplant, at the shipyard, or in tbeship, as agreed. OperatiOnai testsshall be conducted on each unit aftercompletion of installation.2.2 Nitrogen Systas2 .2.1 The liq.didnitrogenioading aridstorage system andgaseous nitrogen generation systemsshall be tested to demonstrate satis-factory operation and to verifyperfomance.2.2.2 The performance test maybe conducted on a prototype or thefirst unit at the manufacturer 1splant, at the shipyard, or in theship, as agreed. Operational testsshall be conducted on each unit aftercompletion of installation.2.3 Cgogenic Pipinq2.3.1 All liquid and gascryogenic piping shall be dried withwam dry air if available and condi-tions require, and then with inert gasor gaseous nitrogen. At the end Ofdrying, the de~oint should be -40QC,or as agreed.2.4 HOla spaces2.4.1 The hold spaces, inter-barrier spaces, insulation spaces, voidspaces, etc., which are required by thedesign to be dried or inerted, shall bedried, or inerted using dry air, inert

gas, or gaseous nitrogen as required,until tie dewint is -40C or asagreed.2.4.2 ~f inspection of insulationafter cooldmn is required, the details

shall be as agreed upon for thepertinent containment system design.2.4.3 The space relief valvesshall be tested and set pressure veri-fied at a suitable point in.theprocedure, if not previously done.2.4.4 Nhere hold spaces areinerted the gas conditions at theend of tie inerting shall be 5 percentmaximw oxygen by volme and 95 percentmininm inert gas by volme or asagreed.2.5 Carqo Tanks2.5.1 Cargo tanks shall be dried(with ~ air if available and condi-tions requ=) and inerted with ~

~r;nz~s%sg~td~i~ %I?;;f5 percent maximm oxygen by volmeand 95 percent minimm inert gas byvolme or as agreed.2.5.2 The cargo tank reliefvalves shall be tested and pressuresetting verified, at a suitable pintin this procedure, if not previouslydone.2.5.3 Immediately prior to initialloading of LNG, the inert gas shall bedisplaced using afiient temperature LNGgas from shore, or from the ships

vaporizer (see section 4). The inertgas displaced may be discharged via thevent riser, or as required by localauthority, continuing until C02 iS leSSthan 500 pm, or as required by localauthority and shore teminal. If nitro-gen is fie inert gas, displacement may.teminate when the dew point is loweredto 75C. (AISO see 4.1.6. )

2.6 Insulation2.6.1 If required by the design ofthe system, the insulation shall beinerted with gaseous nitrogen, untilthe 02 content is less than 5 percent,

the dew point is -40c, or as agreed.Operation of the pressure control(replenishment and venting) systa shallbe daonstrated.

2.7 Scope and Duration of Tests

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2.7.1 Automatic and manualcontrols, bypasses, safety devices,instrumentation, optional modes ofoperation, etc. , shall be demonstrated,where applicable, during each of theforegoing tests and operations.2.7.2 Duration of the foregoingtests shall be sufficient to demon-s-ate satisfactory operation and toobtain representative Wrfomnce data.2.7.3 Duration of purging,drying, and inerting operations will bethe time required to reach the speci-fied or agreed perfomance/operatingconditions. In other tests, theduration should be det$mined by prioragreement. The follwing are suggested:Inert Gas Plant - Performancetest - 2 to 12 hours depending on typeof dryer and regeneration cycle.Nitrogen SYStem - Performancetest - 4 hours; Op=ational Test - 1hour .

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3.0 COLD TSSTING OF DECK ~CHINBRY ~DPIPING3.1 General3.1.1 A1l deck piping and cargoequipment and related instrumentationand controls should be tested with coldnitrogen gas in the shipyard prior togas trials. This cold test is con-ducted before the cooldown and testloading so that hot work or othermodifications can be made withouthaving to gas free cargo tanks.3.1.2 Before the come= cementof cooldown and test loading of thetanks, a cold test of all deckpiping and cargo equipment should bemade using cold LNG gas or gaseous

nitrogen down to -160c.3.1.3 Prior to commencement ofcold tests, the following precautionsshould be taken:

(a) Fire PWPS, firehoses, water monitors, deck spraysystems, and dry chemical fire fightingequipment should have been testeal,andfire hoses laid out and charged asrequired by Regulation.(b) Drip pans and theirheating coils, if fitted, should beoperational.(c) All connection, in-cluding ship/shore grounding connectionsand communication facilities should beoperational.(d) Mechanical ventilationsystems seining enclosed spaces contain-ing cargo handling equipment should beoperational.(e) All cargo pipingshould be inerted with gaseous nitrogento preclude he presence of air or inertgas containing Carbon Dioxide.

3.2 LNG VaporiZer3.2.1 LNG vaporizer to be testedfor satisfactory operation of both LNGand stem control systems.

(a) Vary LNG flow ratesfrom minimm to maximw to checkresponse time, st~ility and ability

of control system to maintain setpoint pressure.(b) Vary outlet temperaturecontrol from minimm to maximum tocheck for stability and adequacy Ofcontrol.(c) Vaporizer to be operatedon both manual and automatic control.

3.3 Vapor Header Pressure ControlValve3.3.1 Vapor Header Pressurecontrol valve (if fitted) to be testedfor ability of control system to main-tain set paint pressures- when operating~o~t::y on manual and automatic

3.4 VaPOr Header Mast Heater3.4.1 Vapor headermast heater(if fitted) to be tested for satis-factory operation to meet specificationsTests can be made concurrently withportions of vaprizer test. Gas inlet-outlet temperatures to be checked fromminimw to maximm available or speci-fied flow rates.3.5 Boil-Off Gas Compressors3.5.1 Boil-off Gas Compressors areto be tested for satisfactory operation.

verify satisfactory operation of thefollowing:(a) Bypass - Surge FlowControl.(b) Temperature slams andshutdows .(c) Compressor seal pres-sures, if nitrogen seals are used.(d) Check for leaks at allconnections with portable gas detectorsin both warn and cold conditions.

3.6 Boil-Off and Warn-UP GasHeaters3.6.1 Boil-off and warm-up gasheaters are to be tested for satis-factory operation of:

(a) Temperature slams andshutdwns.

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(b) Response time and stabil-ity of temperature controls to maintainset point temperatures from minimm toma.ximw available or specified gas flowrates and for range of gas temperatures.(c) Steam or water-glycolheating systas to meet performance

rwuirements of specifications.3.7 Boil-Off Disposal System3.7.1 Gas burning and stem dmpsystem (cr other boil-off disposalsystem as provided) to be tested foroperational control at the dock usingvapor from vaporizer, compressor orgas-heater tests. Additional testingwill be required for at-sea condi-tions.3.7.2 The automatic shutdown ofthe gas burnins equipment should bedemonstrated.3.7.3 Dockside test should demon-strate ability of boil-off disposalsystem to handle full boil-off volmesof LNG vapors.3.7.4 The odorant systm, iffitted, will be tested fOr PrOP.eroperation, flow, pressure, includingautomatic shutdown.

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4.0 DI SPLAC~NT OF INERT GAS ANDcOOLDO~

4.1 Displacement of Inert Gas4 .1.1 Using LNG vapor from shoreof from the ships LNG vaporizer, dis-place inert gas in the ships tanks byintroducing LNG vapor at the top of tbetanks.4.1.2 In order that.a stableinterface between LNG vapor and inertgas may be maintained to assist in dis-placement, it is recommended that thetemperature of the LNG vapor at theva~rizer outlet be no less than tiient.If it is not possible to maintain thistemperature, it should under no circu-mstancesbe alloh.edto fall to less than

the dew point of the inert gas plus 5degrees C.4 .1.3 Inert gas should beremoved from the tanks through liquidfill connections or other piping atthe tank bottom. The inert gas shouldbe directed to the shore terminal fordisposal or may be vented to the atmos-phere on the ship as applicable regula-tions will pemit.4.1.4 Before completion of dis-placement procedure cargo preps and

pamp colms should be purged to removeall traces of inert gas. Procedure isto be detemined by ships pipingarrangement.

4.1.5 Before completion of dis-placement procedure, all deck pipingand equipment not utilized during dis-placement operation should be purgedof inert gas. Procedure is to bedetermined by ships piping arrange-ment.4.1.6 End point of displacementof inert gas shall be dependent uponcomposition of inert gas. If inertgas contains measurable quantities ofcarbon dioxide, displacement shallcontinue until carbon dioxide content,as measured at the outlets from thecargo tanks is no greater than 500 ppm.If nitrogen is used as an inertingmedium, displacement can be consideredas complete when the dew point islmered to -75C.4 .1.7 Care should be taken toinsure that the displacement opera-

tion is conducted in such a way as tomaintain as stable an interface aspossible. In addition to temperature,it is important to control LNG vaporinlet velocity, particularly duringthe initial stages of displacement,.

4.1.8 Gas detection equipmentshould be operating during displacemento?eration. Monitor gas detection equip-r.entregularly throughout operztion.4.1.9 Void space or interbarrierspace pressure control equipment shouldbe cperating during displacement opera-tion end should be monitored regularly,particularly if cold LNG \,apor is used.4.2 Cooldom4 .2.1 Prior to start of cooldownoperation, ensure that the cargo liquidfill valves at all cargo tanks areclosed.4 .2.2 The vapor piping systashoul~ be aligned to allow properdisposal of LNG vapor generated duringcooldon . Vapor nomally should bedirected to.the shore, but maY bevented to amosphere through ship s ventpiping if applicable regulations pemit.4.2.3 Gas detection equipmentshall be operating during cooldom ofcargo tanks and piping. Ail wintS

should be monitored regularly duringentire operation.4.2.4 Void space or interbarrierspace pressure control equipment shallbe operating during cooldown. Voidspace or interbarrier space pressuresshall be monitored regularly, as shouldinert gas or nitrogen consumption.4 .2.5 cofferda and/or wing tankheating systems if fitted shall be opera-ting during cooldom.4.2.6 Hull steel temperaturesensors shall operate continuously

during cooldom. Hull steel tempera-tures shall be monitored regularly.4.2.7 Cargo tank and insulationtemperature sensors shall operatecontinuously during cooldown. Alltemperatures shall be monitored atregular intervals throughout the cool-down.

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4.2.8 Open valves to cooldownspray nozzles on one or more cargotanks, and adjust LNG flow rate orpressure drop across spray nozzles tomeet requirements of the approvedcontainment system design.4.2.9 Monitor cargo tank vaporpressure regularly throughout cooldomto ensure that proper disposal of LNGvapor can be maintained, particularly

if vapor is being returned to the shoreteminal. LNG flow rate should headjusted as necessary, if vapor pres-sure rises to the point where reliefvalves open.4.2.10 The criteria established

by the approved containment systemdesign shall be followed in all cool-down operations. In ?eneral, thecooldown rate should be adjusted toensure that thermal gradients inthetank structure do not lead to stresseswhich exceed tank requirements.4.2:11 The end of cooldotinshallbe determined in accordance with theapproved cargo containment systemdesign. In general, end of cooldownnay be assumed to occur when tankbottom temperature has reached between-140C and -162=C depending upon thecomposition of the LNG. Verticalthermal gradients must also be con-sidered with certain contaiment syster,designs. h%en cooldown is completetanks are ready for loading.

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5.0 LNG MDLING5.1 General - The tests andprocedures as described in this

Sectiw,ldetemine the adequacy of opera-tion of all portions of the cargo systemthat handles LNG. The tests of Sections2, 3 and 4 shall be completed andthe tanks are cooled down prior to thecomencenent of LNG handling tests. A1lnecessary equipment shal1 be operation-al and in service for the safe handlingof LNG.5.2 Loading and Testina Phase I5.2.1 Load sufficient LNG intoeach tank to raise liquid level abovelow level alarms/shutdowns.5.2.2 Operate each cargo, cool-down, and stripping pmp for shortperiod on recirculation.5.2.3 During the foregoing,record the discharge pressure, amperageand voltage for each pup.5.2.4 Operate each cargo, cool-down, and stripping pup and check lowlevel slam and shutdm by pwpingliquid from one tank to another, also,where installed, check low currenttrip.5.2.5 Observe liquid levelgauges, the operation of nitrogensupply system and storage, boil-offgas system and piping movement duringabove operations.5.2.6 Nbere applicable, inspectexpansion joint between cargo tank domeand ship *s structure and cargo tankdome top elevation relative to ship andmeasure and record.5.3 LNG Loading and TestinqFhase 25.3.1 Load additional cargountil total quantity of LNG on boardis approximately 1.25 times thecapacity of the vessels largest LNGtank. If sufficient quantity of LNGis not available to allow largest tankto be filled plus a heel of liquid ineach of the other tanks, certain testssuch as overfill shutdown, high levelslams, upper range of liquid level9au9es, etC. , must be postponed untilfirst loading.

5.3.2 AsSwing cargo has been dis-tributed between all tanks (part load)inspect steel structure and doublebottom tanks for cold areas .Note: In some designs this canonly be done if deballast-ingof spaces is possiblewithout affecting trim andstability, or these stepsmust be postponed untilafter completion of firstloading.5.3.3 Nbere applicable , measureand record cargo tank tcp elevationrelative to ship.5.4 Fill One Cargo Tank and TeSt5.4.1 Operate main cargo preps inall but one tank to pmp into one tanksufficient LNG to fill tank.5.4.2 Observe liquid level gaugesin this tank, and in others as cargo is

D~Ded frOm tank to tank. Also record~m~ diScharge pressure, motor amperageand voltage.5.4.3 Observe tank temperatureindicators in all tanks and record.5.4.4 Check high. level slam,automatic closing of tank fill valves,and test specific gravity indicators,if installed.5.4.5 Overfill tank and test highlevel slams and aergency shutdwns.5.4.6 Inspect wing tanks andcofferdms or spaces adjacent to eachfull tank for cold areas after insola-tion has cooled down. Monitor regularlyair temperatures in tiese spaces ifempty.Note: In some designs this canonly be done if deballastingof spaces is possible withoutaffecting trim and stability,or these steos must be nest-poned until ~fter cimpi~tionof first loading.5.4.7 Nbere applic*le, inspectexpansion joint between cargo tank domeand ship *s strctre and cargo tank dometop elevation relative to ship andmeasure and record.

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5.4.8 Operate the spray system inall tanks (except the full tank) andrecord all performance data.5.4.9 Ouring the above operationsobserve piping and expansion joints fortightness, expansion/contraction. In-spect piping insulation for breaks,cracks, frost spots.5.5 Filling and Discharging EachCargo Tank5.5.1 Pmp LNG from full tank toothers in succession testing equipmentin sme manner as indicated in 5.4.5.5.2 Strip tanks in successionwhen main cargo PWPS are shut dwn tocheck operation of all stripping PWPS,if fitted.5.6 Observations5.6.1 Monitor all gas detectionpoints regularly during time LNG isaboard the vessel.5.6.2 Yonitor the operation of

nitrogen system and boil-off gassystem including gas burning if inuse during above operations.5.6.3 Record and plot wherefitted and applicable:

(a) Tank vapor headerpressures and temperatures.(b) LNG tank temperatures,insulation temperatures, and inner hulltemperatures.(c) TOP key temperatures,where pertinent.(a) void space or inter-barrier space pressures.(e) Wient air and seatemperatures, and barometric pressures.(f) Interbarrier gas con-centration and purge rfite.

5.6.4 Record weather and seaconditions at 4-hour intervals.5.6.5 Check operation of bulkheadand hull.beating arrangements, if fitted,and record taperatures .5.7 Special Remarks5.7.1 It may be Wssible to runtests as indicated in this section alongside berth and then sea tests would befirst full ship voyage.5 .7.2 If it is not possible torun tests as indicated in this section

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along side berth, it is suggested thatvessel proceed to sea after completionof 5.3.5.7.3 Filling each cargo tank insuccession, as in 5.4.1 and 5.5.1, inport or at sea, may require appropriateballasting to avoid excessive trim, hullstress, etc.


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6.0

tankheat

BOIL-O?F HANDLING6.1 General .6.1.1 In order to prevent cargopressure from increasing due toleak throuqh the insulation,boil-off va?ors-are removed fromthetanks by means of a piping system andthe gas compressors (s). Kom,ally thegas is compressed, heated to atiienttemperature, and used as fuel in thepropulsion system to au~ent the

nomal fuel.Note: This Guide does not coverpropulsion-machinery trials whichshould previously have been satis-factorily completed if suchmachinery is involved with hand-ling boil-off.

Ouring gas trials, all components ofthe boil-off handling system should betested for individual performance andas an integrated system. The followingis a list of those functions and com-ponents which require testing.6.2 Gas Compressor - See Section

3.0 and verify the operation of thefollowing, where fitted:a. Overspeed trip.b. Vibration trip.c. Discharge temperaturetrip.d. Surge controls.e. mergency shut-dmns.f. Ltie Oil pressure/tempera-ture trips.

6.3 Boil-Off Heaters - See Section3.0 and verify the operatfon of thefollming, where fitted:a. Low gas exit tempera turetrip.b. Heat exchanged fluid leveland temperature.

6.4 Operational Trials, VentinqPemitted6.4,1 After completion of testingof the above functions, and zny otherupon which the safety of the gas burningsystem depends, the system is ready foroperational trials. Systm operationtrials for the boil-off handling systemshall proceed as follows if short-ternatmospheric venting is permissible:6.4.2 Nhere possible and pemitted,align valves from cargo tank through

compressor (s) and boil-off heater (s) todischarge to atmosphere. This will allowtie operation of compressor and heatercontrols to be checked without influenceof the cotiustion control system.6.4.3 Start compressor and heaterand place in automatic control mode.By manual throttling of compressor inletand heater discharge, variation ofboil-off rate and engine room daand canbe simulated. Response of compressorand heater controls can be checked.6.4.4 By quickly shutting 9as ,flOwa trip of gas-to-engine room valve is

simulated to test operation of surgecontrols (centrifugal compressor) orpressure relief system (positive dis-placement compressor) .6.5 yerational Trials, No Venting.6 .5.1 If venting is not per-missible, the system operation trialshall proceed as follows:6.5.2 Align valves from cargotank through compressor (s) and boil-offheater (s) to discharge to engine room.Alert engine room of intention tocomence gas burning.6.5.3 Check operation of slamin annular space of dotile wall gaspipes.6.5.4 Check operation of gasdetector in ventilation hood over boilerfront for compliance with RegulatoryBody Requirements.

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6.5.5 Start compresso> and heater- and infom engine room of availabilityof gas.6.5.6 Initiate gas burning bycomand from engine room.6.5.7 After satisfactory com-bustion is attained, vary gas demandfrom engine room to test compressorand heater controls.6.5.8 Trip gas-to-engine roomvalve to operate surge or pressurecontrol device. Compressor shouldeither vent gas or shut down, dependingon operating mode selected.6.5.9 Demonstrate that satis-factory cotiustion :S maintained inthe event of loss of gas fuel supply.6.5:10 Check operation of mastergas shut-off valve and the block andbleed valves at ,the burner by allcontrols or sensors.6.5.11 The ability to burn

varying ratios of 9as to fuel Oilshould be demonstrated at varyingpower levels.6.5.}2 100% gas burnin9capability, if fitted, shall bedaonstrated.6.6 Alternate Propulsion Systm6.6.1 If gas turbines or dieselecgines are used for propulsion, themeans of disposing. of excess boil-offgas (in lieu of steam dmtp) shall be


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7.0 WA~UP AND GAS F=EING7.1 General - The warmup and gasfreeing system shall he tested to

demonstrate satisfactory o?eratio.:.This test may be performed at thecompletion of gas trials, after servicevoyages, or as agreed.7.2 Tests and Operations7.2.1 The cargo tanks shall bestripped of cargo to the minimm level.7 .2.2 The cargo tanks shall bewarmed up, using the warmup systemincluding compressor (s), warmu? heat-er(s) , heating coils, controls, etc. ,as applicable, until the required tanktaperature is reached. As thetemperature and pressure rises, the

excess vapor may be burned in thepropulsion machinery, sent ashore, orvented to the atmosphere, as agreedand pemitted by local authority. Thelatter may require proceeding to sea.7.2.3 %en tie required tanktemperature of 5C, or as agreed, isreached, the cargo tanks shall bepurged with inert gas (which may berequired to be done at sea) . At theend of inerting, tie gas compositionshall be 5 percent by volume hydro-carbons or less or as agreed.7.2.4 Then the cargo tanks and

hold spaces (as required for inspec-tion) shall be aerated. At the end ofaerating the gas conditions shall beat least 18 percent oxygen, O.25 per-cent hydrocarbons, or as agreed. Safeconditions shall be maintained byadequate ventilation throughout thetest and ins~ction period, and theyshall be monitored.7.3 Scope and Duration7.3.1 Automatic and manualcontrols, bypasses, safety devices,instrumentation, optional modes ofoperation, etc. , shall be demonstrated,

where applicable, during each of theforegoing tests and operations.

7 .3.3 The duration of the warm-up and purging operations, will be thetime required to reach the specifiedor agreed terminal conditions7.4 Safety Precaution.7.4.1 If the insulation has beenexposed to LNG, precaution must betaken to maintain safe atmosphericconditions.

7.3.2 DuratiOn of the foregoingtests shall be sufficient to demonstratesatisfactory operation and to obtainrepresentative performance data.

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. . .

8.0 FIRST FULL LOAD AND DISC~RGE8.1 Upon arrival at loadingport, carefully inspect on-deck por-tion of cargo piping system for anyweather damage incurred enroute.Check instrwentation and controlsystems for correct operation. Testemergency remote valve closin~ system.Check operation of gas detectionsystem, and note readings in spacessurrounding cargo tanks; determinecauses of any non-zero readings. .Yakesure means of leak protection (drippans) are available and fire hosespressurized in case of leakage duringpiping cooldown. Check liquid levelof the nitrogen tanks. Arrange forship-to-shore connections and cGmuni -cationsE .2 If cargo tanks were gasfreed after initial pOrtiOn of tlialS,inert and dry cargo tanks as perships operations manual.E.3 Prior to cooldown of tanks(or if tanks are already cold, priorto start of loading) , cooldown on-deckliquid piping as much as practicalusing ccld cargo vapor, ?ressurizeliquid piping circuits, and inspectflange connection for leaks produced~,,wcrking of piping at sea. Con-tinue cooling down with LNG andre-inspect flanges and valves for

leaks.8.4 If not already in operation,check cofferdam hull and ballast tankheating system (if fitted) and pressurecontrol system for insulation spacesand all similar spaces which wiilrequire nitrogen make-cp during cool-down.8.5 If tanks are not already cold,perform tank cooldown as per Section4.0 and ships operation manual8.6 Simultaneously load alltanks , using shipboard compressor (s),if so designed, to return cargo vaporto shore. Note 10ading time requiredand compressor performance.8.7 During loading, monitor andrecord insulation s?ace (or inter-barrier space) gas concentration and

.,. purqe rate if a continuous flow ofinert gas is used in the space.

8.8 On completion of loading,note and record volme of cargo loaded,temperature, and density. If shipboardinstrumentation is used, compare densityreadings with density and compositionvalues determined by shore.8.9 If high level alarms have notbeen previously tested, on completionof loading, transfer liquid successivelyfrom one tank to another to test highlevel zlarms and fill valve shutdown.Check accuracy of level gauges oneagainst another (if more than one typeper tank) and compare actual high levelalarm actuation point a?ainst desiqnactuation pcint, taking into accountrelative location of gauges and anytrim or list.8.10 Monitor insulakio~ and innerhull temperatures using instrume~tstionprox,ided. In addition, if possible,make physical inspection of the \.armside of the cargo tank insulation or theinsulated winq tank and ccfferdam areasto check for cold spots . Continueclose monitoring of temperature and, i:possible, periodic inspection of innerhull and cofferdams 72 hours after com-pletion of loading.8.11 Yake strain mezsurer,ents onhull and/or tank supports as appropriateto particular tank design.8.12 During voyage, mcni tor an?record:

(a) purge rate in inertedspaces.(b) cargo press=re, tempera-ture, etc. (c) hull and/or tank strainas appropriate.(d) sea and air temperature,barometric pressure, and ship iog dzta.(e) boil-off burned ES fuel.(f) boil-off vented (if any) .(q) gas concentrations in allmonitored spaces.

8.13 In calm water, demonstratecapability of tiil-off handling systemto maintain constant pressure in cargotanks for minimm of 12 hours. !\*en sea

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conditions are suitable, shut downboiloff handlinq system, and witi tanksclosed in, measure rate of pressurerise in tanks until 80 percent of tankrelief valve setting is reached, or for12 hours, whichever is less. Restartboiloff handling systm to reduce tankpressure to a value mutually agreeableto receivinq teminal and ship o~rator.If cooldom spray lines or top filllines are provided, check the effect ontank pressure of recirculating liquidin the tanks.

8.14 Prior to discharge, cool-down cargo piping and again check forleaks due to working at sea. Checkthat vaporizer is in operating condi-tion.8.15 Prior to discharge, recordcargo volme, temperature, pressure anddensity.8.16 Discharge cargo using theprocedure in the ships operationmanua 1.8.17 Note total time to dis-charge, and note liquid level., tankpressure, and flow rate at which PWPSlose suction.

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9.0 GLOSSARY OF TER~lS9.1 As agreed - as used hereinmeans as defined by contract, speci-

fication, a?vroved trials procedure Oragenda or other written agreement.9.2 Boil-off - is the gas_resulting from vaporization of the LNGcargo.5.3 Boil-off rate - is the Per-cent per da= cargo capacity of puremethane which is vaporized due to heatleak into the cargo.9.4 ~rgo containment system -is the arrangement for containment of

cargo including, where fitted, a P~imarYand secondary barrier, associated in-sulation and any intervening spaces,and a5jacent structure if necessary forthe supFort of these elements . If theseccn~zry barrier is part of the hullstructlre it may be a boundary of thehold space.

?.5 _.carqotank - is the liquidtight shell designed to be the primarycontainer of the cargo and inclu~es allsuch containers h,hetheror notassociated ~vith insulation and/orseconnsulation space - is thespace, which may or may ot be an inter-barrier space, occupied wholly or inpart by insulation.9.14 lnterbarrier space - is thespace betb.eena primary and z secondarybarrier, whether or not completely orpartially occupied by insulation orother material .9,15 Operational test - is ademonstration of proper operztion k.hichshows correctness of construction, manu-facture and installation.9.16 Performance test - is ademonstration of performance capabilityunder conditions which closely duplicateoperating conditions.9.17 Primary barriers - is theinner element designed to contzin thecargo when the cargo contair,ment systemincludes twc boundaries.9.18 Regulatory bodies - meansthe organizations designated by theowner or by lab,to enfcrce regulationsrelative to the safetv of the ship, itscrew or cargo, for ex~mple: u. S. Coast

Guard, U.S. Public Health Service,Canadian Ministry of Transport.9.19 Red hand settinq - POSitlOnof an adjustable fixed marker on aninstrment, which prescribes the limitsof safe operation.

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25/26

9.20 Secondary barrier - is theliquid resistinq outer elaent of aca~go contaimekt system designed toafford temporary containment of anyenvisaged leakage of liquid cargothrough the primaw barrier and toprevent the lowering of the tempera-ture of the ships structure to anunsafe level.9.21 ~ - used to expressobligation for compliaricewith this

Code.9.22 Should - expressesrecommendation of this Code.9.23 Tank cover - is theProtective structure intended to~rotect the cargo containment. systemagainst dmage where it protrudesthrough the weather deck and/or toensure the continuity and integrityof the deck structure.9.24 Tank dome - is the upwardextension of a portion ofthe cargotank. For below deck cargo Coxtaiment

systems the tank dome protrudes throughthe weather deck or through a tank cover.9.25 Tank dome altitude -measurements taken of cargo tanks whichprotrude above the weather deck, or tankdomes , or tanks which have covers thatproject above the weather deck, inrelation to the deck in the tiientcondition and then in the cold servicecondition.9.26 void space! - is the en-closed sDace in the carao area externalto a ca;go containment ;ystem, notbeing a hold space, ballast space, fueloil tank, cargo pwp or compressor room,or any space in normal use by personnel.

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SHIPS, MACHINERY%4 :37:>9:%103-11:3.12$143.153-17$18:3-19:3203-21:%223.233.253.263-2?3.20

Calculation 01StOPPinQ Atil ity of Ships (19~)Invest igat ion 01 Propel ler.Mub Seatino Arrangements (1?59)Repoti of Task Group on Sewice PO*er AllOwa...S (19611Guide to Propulsion Reduction Gear Allgnment anti Installation (1961)Marine Sleam Power Plan! Heat Balance Pr2ctices (Revised 1973)RePofi on StiF Operator., Experience. with Stern Tube Bearing Wear (1962)Eoi!e, Furnace Ferformace Criteria, Group (1963)Guide 10 !he Design and Te5tinQ of Anchor Windlasses !or Merhat SMPS (1%4)Recommended Practices for Correcting steam POwel Plant Tr ial Performance (1=)safety Considerations for N. Clear Power pla.f$ 0. Mercha.1 SWPS 11%5)S.ggesled Methods of Reconditioning Cast Copper Bzse Tail shaft Uers (1967)Glde!o:the DesiQn 01L ine Shafl Co.pfl,!gs (1%81Prope flies Of Lignumvilae and lts Useasa B.a,ing Matecial (1967)Reliability ad Maitainati lily Egieedng i the Marine lndst~ (1971)Guide for Centralized Contrc! and A.toma!io. 01 Stips Steam Propulsion Plant (1970)Ship Operallng Expedience withal Lbri.sled %ern Tube Bearinos [1971)Marine Power Plants Icc the 1970s (1974)Marine Diesel Pcwer Plan! Per!omace Practice$ 11975)Gas Tur>ine Powel Pla.$ Petiormance Practices 17976)

SHIP TECHNICAL Operations4.; : Transoceanic Routing of SMPS Based on MeleoroloQ!ca! Forec2sl (195~4.4 : Repoti on StiPs Stares and Installed Cargo Refrigerated Eoxe$ (1962)4.5 : Special cargo Tanks 10: DV Cargo Ships (Revised 1965)4.7 : Thermal Ins.(.tion Repon (1963)4-9 : Abrasive filastig Guide for Aged 0: Coated Steel Surfaces (1969)4.70 coating Syslems Guide for Hull, Deck and Supers trclure (Revised 1973)4.12 Guide for SMpboard Crane Specitlcations (1972)4.13 Indexed Abstracts of Marine computer Programs (197014.14 Gidefor S.pplementaV Venlilalion ina Ship,s Cargo HO!dwhe Using l!ernal Combustion Engines (1970)

SHIP PRODUCTION&l : Analysis of ShipyarG Cost Repofling Systems (1972)

MARINE SYSTEMS$1 : Adva.ced Stiace C,af! Economic Model (1976)

TECHNICAL AND RESEARCH SYMPOSIUMS51 : Some E!lects of Hull Form on Ship Performance in a Seai.ay (19N)S-2 : Hull Stresses 1 Bulk Carriers i the Great L2kes 6nd Gull of S1. Lawrence Wave Eviro me! (!971)Pleaseotehat B!fel;.s 2.77and 2-18 . ,. companioniecesoS.2%3 : Seakeeping, 19531973(1974)S.4 : Propellers ,75 (19761

TECHNICAL AND RESEARCH REPORTSThe Iollowig ,epofls,eslllng,omi.esl;gafioso,heTe.hn;ca! ad Resea,ch P,ogram of THE SOCIETY OF NAVAL ARCHITECTS ANO MAENGINEERS. a,e also 6vai!able. These ,eports usalfy ;nclude mucfi sell ito,mafi?n but may .1 ecesse,;ly ,ep,esent concfsive ,esearch.

R.1 : Oq.amic Calibration 01W.,, Probes (1%3)R.2 : Summaw Repon 01 the lnvestiQat ion of Tail. shaft failures 1?9661R.3 : Obsewatios cl Unsteady Airloil Flow. (1%6)R-4 : Feasibility.! a ShoR.Cresled Tank FacilitY 10I ShiP Model St.diEs (1%6)R-5 : Feasibility of Mea$rig Strain. Corre$poding to Beding Moments with Several I!lection Points (i%7)R.7 : Hull Form Etfect o Resistance in Smooth Water and Waves (1969)E.8 : Comments o Semite Margins for Ships (19701R.12 Slammlg P,,.. ,,, on a Barge Model (1971)R.13 Deep Ocean Simulation Facil ities 01 the united Slates (1972)R.14 References o Ferro-Cement in the Marine Environment! (1972]R.15: Longild inal Sbffess of Main Thrust Bearing Foundations (1972)R.76: Smey of Shipya,a Material Handl ing Systems (1973)R.17: GlossaT for High. Speed S,face Cralt (1974)R.?& Effects of Bottom Maintenance on FdctiOnal Resistance 01 StiPs (1975)R-19 OY.amic Slosh Induced Loads o Liquid Cargo T8nk Bulkheads (1975)R.20 Commnic.iions in the Marine Terminal (1976)R.21: Fndamenlals 07C athodic Protection for Marine Syslems (1976)R.22 Effect of Rdaer Rate on Maneved.g Performance of a Large Tanker (1976)

m?

panel m-8 special ca.gas trials guide for.jul.1977.t-r

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