INVESTIGATIONSININVASIONINNOVATION;THEARCHAEOLOGICALANDHISTORICALSTUDYOFAWWIILANDING

VEHICLETRACKEDINSAIPAN

WILLIAMSHAWNARNOLD

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Acknowledgements

IwouldliketofirstthanktheAmericanBattlefieldProtectionProgram(ABPP)for

theirsupportincreatingamaritimeheritagetrailfortheWWIIinvasionbeachesof

Saipan.IwouldalsoliketothankToniCarrellandShipsofExplorationand

Discovery(SHIPS)fortheirpartnershipinthiseffort.

IwouldliketothankthestaffandstudentsofFlindersUniversityfortheirhelpand

support.IwouldalsoliketothankallofthepersonnelfromtheHPO,CRM,andDEQ

officesinSaipanespeciallyRonnyandalloftheJohns.Withoutyourhelpthis

projectwouldnothavebeenpossible.ThankstoDavidSteinbergandPeterHarvey

fortheirassistanceandinsightduringtherecordingofthissite.Abigthankyou

goesouttoKathleenDalewhomIhadthepleasureofcorrespondingwithduring

thisprocess.Kathleenwasexcitedaboutthisprojectfromtheverybeginning.Her

fatherwasanLVT(A)crewmanduringWWIIinthePacificandsheistheweb

masterfortheFirstArmoredMarineAmphibiousBattalionVeteransgroup.

Kathleenwentoutofherwaytoprovidemewithagreatamountofhistoric

resourcesandphotographs.IwouldalsoliketothankJasonRauppandaverydear

friendSingaporeChawieforthemanylaughsandunyieldingsupportduringthis

endeavor.

MostimportantlyIwouldliketothankJenniferMcKinnonfortheendlessadviceand

guidance.Thankyoufortheopportunitytoworkwithsomanyfantasticpeoplein

suchabeautifulplace.Withoutyou,thisthesiswouldnothavebeenpossible.

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Contents

1 Introduction…………………………………………………………………………………..1­1

StatementofPurpose………………………………………………………………………….1‐1IntroductiontotheAmphibiousTractor………………………………………………1‐2StudyArea………………………………………………………………………………………….1‐4Approach…………………...………………………....……………………………………………1‐6ResearchDataandResearchQuestions………………………………………………..1‐7SignificanceofResearch……………………………………………………………………...1‐8LimitationsofthisStudy………………………...…………………………………………...1‐9ChapterOutline……………………………………...…………………………………………...1‐9

2 Approach:ProcessAnalysis…………………………………………………………….2­1

Introduction………………………………………………………………………………………..2‐1ProcessAnalysisasaResearchTool……………………………………………………..2‐2ProcessAnalysisasAppliedtothisResearch………………………………………...2‐6

3 HistoryandArchaeologicalLiteratureReview………………….…………….3­1

Introduction………………………………………………………………………………………...3‐1LiteratureReview………………………………………………………………………………...3‐1Roebling’sAlligator………………………………………………………………………………3‐5LVT‐1…………………………………………………………………………………………………..3‐9LVT‐2.………………………………………………………………………………………………..3‐11LVT(A)‐2..…………...…………………………………………………………………………….3‐13LogisticsInvolvedwithLVTDeployment…..………………………………………...3‐14Tarawa..…...………………………………………………………………………………………..3‐15LVT(A)‐1….……………………………………………………………………………………….3‐16MarshallIslands…..……………………………………………………………………………..3‐18MarianaIslands…..……………………………………………………………………………...3‐18LVT‐3&LVT‐4…..…...…………………………………………………………………………..3‐19LVT(A)‐4……..……...…………………………………………………………………………….3‐20Saipan………..………………………………………………………………………………………3‐22Gyukysai…………………………………………………………………………………………….3‐24TheRoleofLVTsDuringtheBattleofTanapagPlains…………………………..3‐26TheInvasionofManiagassa(Managaha)Island…………………………………...3‐27LVTUseAfterSaipan.…………………………………………………………………………3‐28

4 Methodology…………………………………………………………………………………….4­1

Introduction…………………………………………………………………………………………4‐1LocatingtheSite…………………………………………………………………………………...4‐1InitialInvestigations……………………………………………………………………………..4‐1ArchaeologicalMethodology…………………………………………………………………4‐2HistoricalResearch……………………………………………………………………………….4‐3ContinuedArchaeologicalInvestigationsandMethodology.….……...………...4‐6

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5 Analysis……………………………………………………………………………………………..5­1Introduction…………………………………………………………………………………………..5‐1Location………………………………………………………………………………………………...5‐1July2009Findings…………………………………………………………………………………5‐2February2010Investigations………………………………………………………………...5‐3Feature1……………………………………………………………………………………………….5‐5Feature2……………………………………………………………………….………………………5‐6Feature3……………………………………………………………………………………………..5‐10Feature4……………………………………………………………………………………………..5‐11Feature5……………………………………………………………………………………………..5‐11Feature6……………………………………………………………………………………………..5‐12Feature7……………………………………………………………………………………………..5‐15Feature8……………………………………………………………………………………………..5‐16Feature9……………………………………………………………………………………………..5‐19Feature10...…………………………………………………………………………………………5‐20SiteFormation...…………………………………………………………………………………...5‐21Conclusion…………………………………………………………………………………………...5‐22

6 Discussion…………………………………………………………………………………………6­1

Introduction…...……………………………………………………………………………………..6‐1ProcessAnalysisofFeatures…...……………………………………………………………...6‐1OvercomingThreatsandCreatingStrategiesthroughTechnologyandModification……………………………………………………….……………………………...….6‐2ArchaeologicalEvidenceofFieldExpedientArmorModificationsandSalvageEfforts………………...…………………………………………………………..……………………..6‐6Conclusion…………………………………………………………………………………………...6‐12

7 Conclusion…………………………………………………………………………………………7­1

Introduction…………………………………………………………………………………………..7‐1HowWereLVT(A)‐4sUsedinSaipan?………….………………………………………...7‐1HowandWhyLVTCrewsModifiedtheirVehiclesfortheBattleofSaipan..7‐2HowAreTheseModificationsReflectedintheArchaeologicalRecord?…….7‐3WhatistheSignificanceofLVTsDuringtheInvasionofSaipanasitRelatestotheDevelopmentoftheLVTasaMachineofWar?.................................................7‐4SiteFormationPossibilities...………………………………………………………………….7‐5FutureResearchPotential…...…………………………………………………………………7‐6Conclusion……..…………………...…………………………………………………………………7‐7

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ListofFigures

Figure1‐1:LVTprototypebeingfield‐tested.(Photo:http://www.olive‐

drab.com/images/id_roebling_alligator_03_700.jpg)………………………………………….1‐3

Figure1‐2:Approximatesitelocationoutlinedinyellow.(Image:GoogleEarth

accessedMay10,2010)…………………………………………………………………………………….1‐5

Figure2‐1:Muckelroy’sFlowchart(1978,p.158)………………………………………………2‐2

Figure2‐2:Wardetalmodifieddiagramofwreckdisintegration(1999,p.564)….2‐3

Figure2‐3:Gibbs’flowdiagramofculturalfactorsaffectingsiteformation(2006,p.

16)…………………………………………………………………………………………………………………...2‐5

Figure3‐1:Imageshowingexpedientfieldmodificationsofusingsandbagsand

extraarmoraroundtheturrettop.(Photo:DepartmentofDefense[USMC])………3‐5

Figure3‐2:LVT‐1prototypebeingfield‐tested.(Photo:http://www.olive‐

drab.com/images/id_roebling_alligator_03_700.jpg)………………………………………….3‐6

Figure3‐3:LifeMagazinearticlefeaturingtheAlligator.(LifeMagazine1937,p.

94)…………………………………………………………………………………………………………………...3‐8

Figure3‐4:Illustrationofgrouserdesignchange.(Image:Mesko1993,p.12)….3‐12

Figure3‐5:ComparativedrawingofLVT‐1andLVT‐2.(Image:Mesko1993,p.

9)…………………………………………………………………………………………………………………...3‐13

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Figure 3‐ 6: Design changes of LVT‐2 and LVT (A)‐2. (Image: Mesko 1993, p.

13)…………………………………………………………………………………………………………………3‐14

Figure3‐7:ComparativelinedrawingofLVT‐2andLVT(A)‐1.(Image:Mesko1993,

p.21)……………………………………………………………………………………………………………...3‐17

Figure3‐8:LinedrawingofLVT‐3andLVT‐4.(Image:Mesko1993,p.17)………3‐20

Figure3‐9:ComparativelinedrawingofLVT(A)‐1andLVT(A)‐4.(Image:Mesko

p.27)……………………………………………………………………………………………………………...3‐21

Figure3‐10:LVT(A)‐5earlyandmodifiedversions.(Image:Mesko1993,p.

33)…………………………………………………………………………………………………………………3‐29

Figure4‐1:ImageshowingexpedientfieldmodificationstoearlymodelLVT(A)‐4

consistingofsandbags,.30cal.bowmachinegunandextendedarmoraround

75mmturret.(Photo:courtesyofKathleenDale)………………………………………………4‐5

Figure4‐2:ExampleoflinedrawingfromBradford2007(p.81)……………………….4‐6

Figure5‐1:ImageofSaipansurveyareacircledinyellow.(Image:GoogleEarth

Dateaccessed10March2010)…………………………………………………………………………..5‐1

Figure5‐2:ComparativeimageofearlyandlatemodelLVT(A)‐4s.(Image:Mesko

1993,p.30)………………………………………………………………………………………………………5‐3

Figure5‐3:PortsideprofileofLVT(A)‐4inTanapagLagoon.……………..…………….5‐4

Figure5‐4:PlanViewofLVT(A)‐4inTanapagLagoon……………………………………….5‐4

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Figure5‐5:DiagramofLVTfeatures.(Image:Arnold2010)………………………………5‐5

Figure5‐7:OverviewofLVT(A)‐4site.(Photo:courtesyofShipsofExplorationand

Discovery)………………………………………………………………………………………………………..5‐6

Figure5‐7:Imageshowingcollapsedportlateralsupportoutlinedinyellow.

(Photo:courtesyofShipsofExplorationandDiscovery)………………………………….....5‐7

Figure5‐8:PhotodemonstratingtheStarboardLateralsupportoutlinedinyellow

with2mscale.(Photo:courtesyofShipsofExplorationand

Discovery)…………………………..…………………………………………………………………………....5‐8

Figure5‐9:Viewofbentverticalsupportoutlinedinyellowwith2mscale.(Photo:

courtesyofShipsofExplorationandDiscovery)…………………………………………….......5‐9

Figure5‐10:Collapsedtransversebulkheadoutlinedinyellowunderturret.

(Photo:courtesyofShipsofExplorationandDiscovery)..…………………………………..5‐9

Figure5‐11:Viewofholesinbow.(Photo:courtesyofShipsofExplorationand

Discovery)……………………………………………………………………………………………………...5‐10

Figure5‐12:Viewofholeinupperbowarmorforwardofthewindscreen.(Photo:

courtesyofShipsofExplorationandDiscovery)…………………………………………….…5‐11

Figure5‐13:.30calcoaxialmachinegunportlocatedatradiooperator’sseat.

(Photo:courtesyofShipsofExplorationandDiscovery)…………………………………..5‐12

Figure5‐14:Concretedarmoredhatchcoverlocatedatdriver’sseat.(Photo:

courtesyofShipsofExplorationandDiscovery)…………………………………………..…..5‐13

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Figure5‐15:Overviewofcabarea.(Photo:courtesyofShipsofExplorationand

Discovery)……………………………………………………………………………………………………...5‐14

Figure5‐16:Viewofinstrumentpanelthroughthesteeringcontrols.(Photo:

courtesyofShipsofExplorationandDiscovery)……………………………………………….5‐14

Figure5‐17:Overviewofportsidepontoonwithlargehole.(Photo:courtesyof

ShipsofExplorationandDiscovery)………………………………………………………………...5‐15

Figure5‐18:DetailofPortsideholeinpontoon.(Photo:courtesyofShipsof

ExplorationandDiscovery)……………………………………………………………………………..5‐16

Figure5‐19:Detailofturrettraversinggears.(Image:Departmentofthe

Army)……………………………………………………………………………………………………………..5‐17

Figure5‐20:Modifiedarmoredshieldoutlinedinyellowandpossiblemachinegun

mountoutlinedinred.(Photo:courtesyofShipsofExplorationandDiscovery).5‐27

Figure5‐21:Detailofmodifiedarmoredshielding.(Photo:courtesyofShipsof

ExplorationandDiscovery)……………………………………………………………………………..5‐18

Figure5‐22:Detailofpossiblemachinegunmount.(Photo:courtesyofShipsof

ExplorationandDiscovery)……………………………………………………………………………..5‐18

Figure5‐23:DetailofLVT(A)‐4engineasitappearsinstalled.(Image:Department

oftheArmy)…..……………………………………………………………………………………………….5‐19

Figure5‐24:Detailofengineinpresentstate.(Photo:courtesyofShipsof

ExplorationandDiscovery)……………………………………………….…………………………….5‐20

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Figure5‐25:Detailofsplashguardsandfenderassembly.(Image:Departmentof

theArmy)…………………………...…………………………………………………………………………..5‐20

Figure5‐26:Damagedfenderandmissingsplashguardoutlinedinyellow.(Photo:

courtesyofShipsofExplorationandDiscovery)……………………………………..………..5‐21

Figure6‐1:ComparativeimageofearlyandlateproductionLVT(A)‐4.(Image:

Mesko1993p.30)……………………………………………………………………………………………..6‐5

Figure6‐2:LVT(A)‐4siteinTanapagLagoondiagramoffeatures.(Image:Arnold2010)…………………………………………………………………………………………………………….…6‐6

Figure6‐1:EarlymodelLVT(A)‐4swithsquaremodifiedarmoraround.50

machinegunturretandwhatappearstobea.50machinegunmountedtotheport

sideoftheturret.(Photo:courtesyofKathleenDale)……………………………………….6‐11

Figure6‐5:FlowchartshowingpossiblescenariosconcerningtheLVT(A)‐4in

TanapagLagoon.(Image:Arnold2010)…………………………………………………………..6‐14

Figure6‐6:Viewofsitefromstarboardside.(Photo:courtesyofShipsofExplorationandDiscovery)……………………………………………………………………………..6‐15

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ListofTables

Table1……………………………………………………………………………………………………………..5‐8

Chapter1

Introduction

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StatementofPurpose

Theadventofamphibiouswatercraftsuchastheamphibioustractorforuse

duringWorldWarII(WWII)isdirectlyresponsibleforsavingnumerousU.S.lives.

Theabilitytodriveinvasionforcesthroughthewaterandovershallowreefsto

deliverthemonshorepreventedconsiderablecausalitiesasitpreventedthe

invasionforcefromhavingtowadehundredsandsometimesthousandsofmeters

acrosslagoonsunderheavyenemyfire(Armagnac 1945, p. 121).Unfortunately,

thesemachineshavebeennearlyforgottenthroughtimeandhavetakenabackseat

totechnologysuchastheplanesandtanksoftheera.

Theamphibioustractor,alsoknownastheAmtracorLandingVehicle

Tracked(LVT),wastheworkhorseofWorldWarIIinthePacificTheater.Their

uniqueabilityofbeingcapableoftravelingbothinandoutofthewaterprovided

themanadvantageothervehicleslacked.Amtracswerecalledupontoperforma

widearrayoftasks.Theserolesincludedeliveringassaulttroopstothebeach,

evacuatingwounded,deliveringsupplies,andactingasmobilecommandpostsand

mobileweaponsplatforms(Croizat1953p.46).

Theaimofthisstudyistofurtherourunderstandingofthesignificanceof

amphibiousvehiclesusedduringWorldWarII,particularlyinrelationtotheBattle

ofSaipan.Thisthesiswillexplorethenecessityofamphibiouscraftduetothe

physicalandenvironmentaldemandsofthebattlefieldthroughtheapproach

outlinedbelow.Itwillalsoexplorethewaysinwhichcrewsmadechangestothe

vehiclesduringthewarinordertoprotectandprolongthelifeofnotonlythe

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vehiclebutalsothecrewsthemselves.Finallyitwillexplorehowthese

modificationsdirectlyinfluencedlaterAmtracproductiondesigns.

IntroductiontotheAmphibiousTractor

ThenameAmphibiousTractor(Amtrac)isageneraltermreferringtoan

amphibiousvehiclethatispropelledonlandandinthewaterbyatracked

propulsionsystem(figure1‐1).Thesevehiclesarealsoreferredtobytheirmilitary

title,LandingVehicleTracked(LVT).FollowingthedesignationLVTisanumber,

whichsignifiestheproductionmodeloftheLVT.An“A”inparenthesissignifiesthat

theLVTisanarmoredversion.Thetitlearmoredcanrefertothefactthatis

coveredinarmoredplatesforassaultpurposesorthatitisequippedtooperateasa

mobileartilleryunit.Theartilleryversionsareeasilyrecognizablebecausethey

havealargecaliberweaponmountedonthetop.

TheLVTisoneofthefirsttrueamphibiousvehicles.Itispropelledbytracks

thatmountcleatsknownasgrousers.Thesegrousersactaspaddlesinorderto

propelthevehiclethroughthewaterandprovidetractionwhilecrossingreefflats

andshorelineterrain(United States Marine Corps Air-Ground Museum, 1997, p. 6).

Amtracsareconstructedofsteelandarekeptafloatbyaircontainedinpontoonson

bothsidesofthevehicle.Thesevehicleshaveasingleenginepropulsionsystem

consistingoftracksmountedonboththeportandstarboardsides.

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Figure1­1:LVT­1prototypebeingfield­tested.(Photo:http://www.olive­

drab.com/images/id_roebling_alligator_03_700.jpg).

CarryingcapacityandtheintendedmissionoftheLVTchangedthroughtime

anddesignmodificationsreflectthesechangesinLVTmanufacture.Theversatility

oftheAmtracallowedfortheeasyadaptationofawiderangeofrolesinamphibious

warfare.ThefirstmilitaryproductionmodelisknownastheLVT‐1.TheLVT‐1saw

itsfirstcombatactionduringtheSolomonIslandscampaignin1943(Croizat1999,

p.112).LVTswereintendedtoonlycarrycargotothelandingzoneoncethe

Marinessecuredabeachhead.However,becausethefringingreefwastooshallow

forthetraditionallandingcrafttodelivertheMarinesclosetoshore,theLVTswere

usedtoferrytheinvadingforcestotheshoreline(Croizat1999,113).Thusbegan

theAmtrac’slifeasatroopcarrierandassaultcraft.Thischangeinroleaffected

militarydoctrinefortheremainderofthewarinthePacific.

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MilitaryleadersrecognizedthepotentialfortheimplementationoftheLVT

asanamphibiousassaultvehiclefromthisfirstcombatuse.Invasionforcesadded

additionalmachinegunstotheirexistingLVTsandplacedordersformoreLVTs

withextramountedweapons(Bailey1986,pp.56‐69).Asthewardrewon,military

commandersdeterminedadditionalmodificationswereneededandtheproduction

ofdiversedesignsforspecialpurposescommenced.Asaresult,adefiniteserriation

ofLVTdesignexistsfromcargocarrier(LVT‐1)toarmoredtroopdeliverysystems

(LVT‐4[ArmoredCab])toarmoredartilleryplatforms(LVT[A]‐1andLVT[A]‐4,

thesemachinesarealsoknownasAmphibiousTanksorAmtanks).

Interestingly,thepeoplewhooperatedthesemachinesalsodevisedwaysto

improveandprolongnotonlytheirownlivesbutalsothelifeoftheirLVTs(Baker

2004,pp.4‐9,253).Theseimprovisations,knownas“fieldexpedientarmor

modifications,”havebeendiscussedbyhistoriansandareobservableontheLVT

(A)‐4siteinSaipan(Boal2006,p.5).Further,thesemodificationsarethespecific

focusofthisstudyinrelationtoindividualandtroopactionasdemonstratedinthe

archaeologicalrecord.

StudyArea

ThisstudywillfocusonanamphibioustractorlocatedinTanapagLagoon,

Saipan,CommonwealthoftheNorthernMarianaIslands(figure1‐2).This

particularAmtracisknownasaLandingVehicleTracked(Armored)‐4(LVT[A]‐4).

Anarchaeologicalconsultingfirm,SoutheasternArchaeologicalResearch,Inc.

(SEARCH)originallynotedthesitearchaeologicallyinasurveyreportin2008

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(Burns2008,pg.84).Nofurtherarchaeologicalinvestigationwasconductedby

SEARCHbeyondpositivetargetidentification(Burns2008,p.84).

InJuly2009andApril2010archaeologicalsurveysofthesitewere

conductedasapartofaprojecttorecordsubmergedWWIIheritageinSaipan’s

waters.Thesitewasrecordedusingbasicmaritimearchaeologicalsurveymethods

ofbaselineoffsets,triangulation,trilaterationandphotographicrecording.Alldata

wascomparedtohistoricalrecordsinordertodeterminetheexacttypeand

productionmodelofthevehicle.

TheLVT(A)‐4isrestingataslightangleinadepthofbetween2feet(ft)(.6

meters[m])and10ft(3.05m)ofwateronasandyareabetweenpatchreefsin

TanapagHarbor,Saipan.

Figure1­2:Approximatesitelocationoutlinedinyellow.(Image:GoogleEarthaccessedMay

10,2010).

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Thelowersuperstructureismostlyintacthoweverthemajorityofexterior

armorplatingandsuperstructureismissingfromtheupperportionofthecraft

aroundtheturret.Alsomissingarethearmortrackcoversandthearmorcovering

ofthecab.Othernotabledamageincludeslarge,jaggedholesinthebowarmorand

intheballastarea(pontoons)onbothsidesoftheamphibioustank.

Duringtheinitialsitevisitresearchersnotedthepossibilitythatseveralfield

expedientarmormodificationsweremadetothisvessel.Boaldefinesfield

expedientarmormodificationsaschangesmadeafterthevehiclehasleftthe

productionfacilities(Boal2006,p.5).Fieldexpedientarmormodificationsmadeto

thisLVT(A)‐4areofparticularinteresttothisstudybecausetheyprovideaglimpse

intotheindividualactionsofLVTcrewsduringthewar.

Approach

ThisstudywillutilizeaholisticapproachtoexploretheuseofLVT(A)‐4sin

theBattleofSaipan.Identifyingtheprocessesthatmayhaveaffectedthissitewill

beusedtodeterminethesite’sformation.Muckelroypioneeredsiteprocess

evaluationformaritimearchaeologicalsitesinhisbookMaritimeArchaeology

(1978).Sincethattimeothershaveexpandedthemethodofprocessevaluation.

Wardetal(1999)expandsonMulckelroy’ssiteformationprocessesmodelby

includingenvironmental,chemicalandbiologicalfactors.Gibbs(2006)identifies

theimportanceoftherelationshipsbetweendocumentary,archeologicalandoral

datasetsinordertorecognizedifferences.Jung(2009)alsorecognizesWWIIwreck

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sitepatternsindeterminingsiteformationprocessesofaircraft.Byunderstanding

thenatureofthesite,alogicalconclusionaboutthesite’sformationcanbeobtained.

Thisresearchwillconductanin‐depthanalysisofdocumentaryrecordsin

ordertobetterunderstandtheculturalprocessesaffectingLVTuseontheWestern

InvasionBeachesoftheSaipanbattlefieldinJune1944andthesitesoftwobattles

onthenorthwesternsideofSaipaninJuly1944.Thisresearchwillalsoconducta

completearchaeologicalsurveyoftheLVTintheLagoontoidentifyimportantsite

formationprocessesevidentinthephysicalrecord.Siteformationprocess

methodologyappliedtothisLVTsiteoffersanincreasedunderstandingintohow

andwhythetacticaluseofamphibiousvehicleswasnecessaryandhowthesitemay

havebeenformedandwhatnaturalandculturalfactorshaveaffecteditsinceits

formation.

ResearchDataandResearchQuestions

Thisstudyproposestoconductarchaeologicalandhistoricalresearchin

ordertobetterunderstandtheuseandsignificanceofamphibiousvehiclesduring

theWWIIBattleofSaipan.Thephysicalandenvironmentalsettingofthebattlefield

willbeexploredthroughhistoricresearch.Historicaldataincludesbothprimary

andsecondaryliterature,photographsandmapscollectedfromtheCombinedArms

ResearchLibrary(CARL)archivesonlineandvariouspublicationsconcerningthe

BattleofSaipan.ArchaeologicaldataincludesthesurveyandmappingoftheLVT

anditsenvironsinSaipan’sLagoon.Thisinformationwillbecompiledandanalyzed

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usingtheprocessevaluationofsiteformationapproachtoaddressthefollowing

researchquestions.

MainQuestion:

WhatisthesignificanceoftheLandingVehicleTracked(LVT)duringthe

invasionofSaipanasitrelatestothedevelopmentoftheLVTasamachineof

war?

SubsidiaryQuestions:

1. HowwereLVTsusedintheinvasionofSaipan?

2. HowandwhydidtheLVTcrewsmodifytheirvehiclesfortheBattleof

Saipan?

3. Howarethesemodificationsreflectedinthearchaeologicalrecord?

Significance of Research

LVTs are a unique vessel that aided in preserving the lives of U.S. troops. Their

significance in battle has been largely overlooked in historic accounts of WWII. This

study will conducthistorical research into the use of LVTs by the U.S. in the Pacific and

fill the historical gap that exists for this vehicle.It will do this through historical research

into the Battle of Saipan and the use of LVTs in this full-scale assault. It will also

highlight the use of one particular LVT located in Saipan and examine specific

skirmishes and plans within the overall campaign.

The LVT (A)-4 was introduced for the Battle of Saipan and marks a definite

change in the equipment and supplies for U. S. troops fighting in the Pacific theater

during WWII. This study is significant because it is the first archaeological examination

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of this LVT type. Thus, it investigates the design, manufacture and use of this vehicle for

the first time. Additionally, it is historically documented that LVTs were often modified

by their crews to enhance capabilities and limit loss in war. This study is the first to

investigate from an archaeological perspective these in-field battle modifications to

compare and contrast baseline manufacture details and standardizations with alterations

made by the user. Further, a "process approach" will be used to review the natural and

cultural factors, which affected the vehicle and site as it is observed today. This approach

has been applied to both shipwrecks and aircraft wrecks but has yet to be applied to

vehicles of this nature.

Limitations of this Study

TheinvestigationsofthisthesisarelimitedtooneLVT(A)‐4.Duetotime

constraintsinthefield,itwasimpossibletosurveyanyotherLVTs.Thusthedata

presentedinthisthesisisrepresentativeofonlyoneLVT(A)‐4anddoesnot

necessarilyreflectalloftheLVTsusedduringtheBattleofSaipan.Thelackof

availabledocumentsrelatingspecificallytothesalvageanddisposalofLVTsin

Saipanlimitstheabilitytodefinitivelylinkthissitetotheseactions.Specific

mentionofLVTsinhistoricaccountsarebriefandsometimesnotpresentin

documents.ThismayindicatethatLVTshavebeenoverlookedordisregardedby

theauthors.

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ChapterOutline

Thischapter(Chapter1)explainsthebasicfoundationforthisstudy.It

providesabriefoutlineoftheapproach,whichwillbeusedinthisresearch.The

limitationsofthestudyalsoareacknowledgedinthischapter.

SiteformationanalysisusingtheprocessapproachisdiscussedinChapter2.

Abriefoverviewofwhatsiteformationprocessesareandhowtheyhavebeen

previouslyusedtoexaminewrecksiteswillbepresented.

HistoricaldatacontainedinChapter3explainsthedevelopmentand

evolutionoftheAmtracfromdomesticrescuevehicletoprovidingdirectartillery

supportduringanamphibiousinvasion.NewLVTmodelsareintroducedafter

majorcampaignsinthePacificduringWorldWarII.Designchangesoutlinedin

Chapter3providethebasisforunderstandingtheimplementationoffieldexpedient

armormodificationsbythemanufacturerinproductionmodelsthroughoutthewar

effort.

Chapter4describesthemethodologyusedinrecordingthesite.Descriptions

ofhowdatawasrecordedareprovidedinthischapter

AnalysisinChapter5describesthearchaeologicalresultsdemonstrated

throughphotographsandscaleddrawings.Thefocusofthischapteristoestablish

allofthefeaturesnotedduringthearchaeologicalsurvey.Thesefeaturesareused

toaidindeterminingthepresentconditioninthediscussion.

ThediscussioninChapter6comparesthearchaeologicalfindingsofChapter

5withhistoricalmilitarydocuments.Utilizingtheprocessapproachtosite

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formationinvestigations,sitefeaturesarediscussedandpossibleexplanationsfor

thefeaturesaregiven.ResearchQuestionswillbeansweredinthischapter.

Theconcludingchapter(Chapter7)presentsanoverviewofallavailable

informationconcerningthesiteformationoftheLVT(A)‐4inTanapagLagoon.The

significanceofthemodificationstothisLVT(A)‐4intheBattleofSaipanandits

impactonfutureAmtracdesignsarealsodiscussed.RecommendationsfortheLVT

(A)‐4locatedinTanapagLagoonarediscussedaswellasfutureresearchconcerning

LandingVehiclesTracked.

Chapter2

Approach:ProcessAnalysis

2‐1

Introduction

Researchquestionsregardingthisstudywillbeaddressedusing“process

analysis.”Processanalysisconsistsofexaminingabroadarrayoffactorsthatmay

haveinfluencedawrecksiteinordertodeterminetheformationprocessesofasite

(Schiffer1976:Muckelroy1978;Ward1999;Gibbs2006;Jung2009).Thesefactors

includeculturalandnatural(biologicalandenvironmental)effectstowhichasite

mayhavebeensubjected.Maritimearchaeologistsadoptedprocessanalysisfirst

fromterrestrialarchaeologistsandhavesinceadaptedittostudyingsites

underwater.Processanalysishasbeenparticularlyusefultomaritime

archaeologistsstudyinghistoricperiodsiteswhooftenuseprocessanalysisforthe

purposeofdeterminingsiteformationwherehistoricrecordsareconflictingornon‐

existent(Gibbs2006,p.4;Jung2009,pp.21‐22)

Ananalysisidentifyingthemanyprocessesthatmayhaveaffectedasite

offersarchaeologiststheopportunitytomoreclearlyunderstandhowasitehas

enteredthearchaeologicalrecordandwhatbecameofitafterwards.Itdoesthisby

placingemphasisonsignificantnaturalandculturalprocessesthatinfluencethe

natureofasite(Muckelroy1978;Ward1999;Gibbs2006,Jung2009).Onhistoric

sitesthesefactorsareidentifiedthroughhistoricalresearchandobservedseabed

distribution.Historicaldocumentssometimesdescribeculturalprocessesthat

affectasitesuchasprimaryandsecondarysalvageandthedisposalofequipment.

Whileobservedseabeddistributioncanalsoprovidecluesofculturalactivitiessuch

assalvageorwreckingbehaviors.Naturalprocessesareidentifiedthrough

observedseabeddistribution,testingandmonitoring.Naturalfactorsthatmay

2‐2

affectasitearewaveenergy,compsitionofseafloorandsediments,theactionsof

marineorganismsandthechemicalbreakdownofasite(Muckelroy1978;Ward

1999;Gibbs2006;Jung2009).

ProcessAnalysisasaResearchTool

Processanalysismethodologyforunderwaterarchaeologyisderivedfrom

Mulckelroy’sanalysisofhowshipwrecksenterthearchaeologicalrecord.Herelates

thatbyunderstandingtheprocessesthathaveintervenedbetweenthetimeofthe

wreckingeventandrediscoveryofthewreck,researcherscanbetterunderstandthe

archaeologicalrecord(1978,p.157).Thisthoughtprocessisillustratedina

flowchart(figure2‐1)(1978,p.158),whichoutlinestheprocessofthewrecking

eventandeffectsoncargoinasimplisticformat.

Figure2­1:Muckelroy’sFlowchart(1978,p.158).

2‐3

Theflowchartisbasicandfollowsasimpleoutlineformula.Asanexample,

Muckelroystatesthatheavieritemssuchasmetalobjectsthatcannotfloatwould

nothavedisappearedduringthewreckingprocess(Muckelroy1978,p.166).

Therefore,alackofheavyitemswouldindicatesalvageoperationsofsomesort.

Assessingthepossibilityofsalvageincludesbothobservedseabeddistributionand

possiblehistoricaldocumentationconcerningsalvagerecords(Muckelroy1978,p.

166).

Wardetal(1999)introducedanewprocessbasedmodelforwrecksite

formationconcerningenvironmentalprocesses(figure2‐2).Thismodelprovidesa

morein‐depthviewofhownaturalforcessuchasthesedimenttypesand

hydrodynamicenvironmentinfluencesiteformation.Alsoprovidedareformulas

formeasuringtherateofcorrosionanddecompositionofamaritimesite.

Figure2­2:Wardetalmodifieddiagramofwreckdisintegration(1999,p.564).

2‐4

Otherresearchershaveexpandedtheanalysisofprocessesaffectingwrecks

toincludeawidearrayofculturalinfluencesanddeliberatedisposalofderelict

vessels.Gibbs(2006)contributesculturalstrategiesthatmayhaveoccurredprior

toandduringthewreckingeventandtheirassociatedarchaeologicalsignatures

(figure2‐3)(pp.9‐18).Thesestrategiesincludebutarenotlimitedto:

• Pre‐impactthreatphaseinwhichtheplanningofavoyageis

conductedandmodificationofthevesselmaybedeemednecessary.

• Pre‐impactwarningphase,whichincludescoursechangesandthe

jettisoningofcargoinordertolightenavessel.

• Impactandtheactionsthataredependentonthenatureofthe

wreckingevent.

• Recoil,whichincludesthesurvivors’salvageofcargoand

establishmentofacamp.

• Rescueandpostdisasterisdefinedasthecompleteabandonmentof

thewreckanditscontents.

Gibbsdescribesthepre‐impact“threat”phaseastheinitialgatheringof

knowledgeaboutthemissiontobeundertaken(2006,p.8).Hegoesontostatethat

theresponsetopotentialconditionstowhichavesselmaybeexposedcanbe

expressedinmanyways,suchasthedesignofanewvessel,themodificationof

existingvessels,equipage,selectionofrouteandstrategyofthevoyage(Gibbs2006,

p.8).Thesevariablescancontributetotheprospectofacatastrophicevent,

responsestocatastropheandthenatureoftheartefactassemblage(Gibbs2006,p.

10).Theexistenceofresponsestothethreatphasecanbecomparedandcontrasted

2‐5

withthehistoricrecord,locationofthesiteandthenatureofdeposition(Gibbs

2006,p.10).

Gibbsrecognizesdifferenttypesofsalvageoperations.Thesearetermed

“opportunistic”and“systematicsalvage”.Opportunisticsalvageisdefinedasashort

durationwithintensefocusonsalvageofspecifictypesofmaterialwhereas

systematicsalvageoccursoverextendedlengthsoftimeinordertorecoverasmuch

ofthecargoandstructureofthevesselaspossible(Gibbs2006,p.9).Gibbsalso

stressesthedifferencesassociatedwithsitesthatresultfromunintentionallossand

thoseregardedasintentionallydeposited.Thisconceptisfurtherexpandedby

Richardsinhisstudyofshipgraveyards,butforsakeofbrevitywillnotbediscussed

here(Richards2008).

Figure2­3:Gibbs’flowdiagramofculturalfactorsaffectingsiteformation(2006,p.16).

2‐6

Likewise,Jung(2009)identifiestwotypesofsalvageinrelationtoWWII

siteslocatedinAustralia.Thesearetermed“primary”and“secondary”salvage.

Primarysalvageisdefinedasoperationsundertakenbytheownersorcrewofthe

vessel(Jung2009,p.19),whilesecondarysalvageoccurswhenindividualsother

thanthosewhoweredirectlyinvolvedatthetimeoflossrecoveritems.This

recoverygenerallytakesplaceafterasiteisabandonedandrelocated(Jung2009,

p.20).

JungalsoincorporatesMuckelroy’sdescriptionofcontinuousand

discontinuoussites.Muckelroydefinesa“continuoussite”asonethatis

concentratedinasingleself‐containedarea,whereasa“discontinuoussite”isone

thathasbeenscatteredandmaybeinterruptedbysterileareas(1978,pp.182‐183).

Siteinterpretationbasedontheseconceptsallowsresearcherstoidentifycultural

activitiesthatmayhaveaffectedthesite.Jungstatesforexamplethatthepresence

ofartefactsandpersonalobjectsinsideavesselmayindicatethatnosecondary

salvagehastakenplace(2009,p.20).Incontrasthealsoexploreshowsitesmaybe

raised,salvagedandmovedtoanotherlocationfordiscard.Thearchaeological

signatureforthesesitesisdescribedasdiscontinuousduetotherandomdepositsof

materialduringthediscardprocess(Jung2009,pp.22‐28).

ProcessAnalysisasAppliedtothisResearch

BothhistoricalandarchaeologicalanalysisofLVTs,theBattleofSaipanand

theuseofLVTsinSaipanwillbeconductedusingtheprocessapproach.As

identifiedinChapter1,certainresearchquestionswillbeansweredinrelationto

2‐7

answeringhowLVTs,andparticularlytheoneunderstudy,weremodifiedbasedon

pre‐impactthreats.AlsoofconcernishowtheparticularLVTsitebeing

investigatedcametobeasitistoday,particularlywithregardstowhetheritwas

lostinbattleatthislocationorwasdepositedthereafterthebattle.Additionally,

signsofpossiblesalvageexistwhichraisequestionsaboutwhoconductedthe

salvageandatwhatstagedidthissalvageoccur.

Byusingpreviousmodelsofprocessanalysisthisthesiswillexplorethose

questions.Gibbs’sprocessmodelwillbemostusefulinrelationtopre‐impact

questionofmodificationandbehavior.TheworkofMuckelroy,Ward,Gibbsand

Jungastheyapplytolossandsalvagealsowillbeusedtocreateaprocessmodelfor

betterunderstandingthesiteformationofamphibiousvessels.

Understandingthevariousculturalandenvironmentalprocessesthatmay

haveinfluencedtheformationofthisarchaeologicalsitearekeyindeterminingthe

reasonforthesite’slocation.Byarchaeologicallyexaminingthesiteandcomparing

thisevidencetohistoricdocuments,disparitiesinthehistoricrecordmaybe

identifiedandagreatersignificancefortheLVT’sroleinthebattleobtained.Site

signaturespresentedintheworkofMuckelroy,Ward,GibbsandJungwillbeusedto

determinethesite’snatureandtheamountofsalvageeffortsconductedonit.This

informationwillleadtounderstandingwhethertheLVTwascatastrophicallylostor

intentionallydeposited.

Processanalysishasnotbeenusedtoevaluateanarchaeologicalsite

involvinganamphibiousvehicle.Thus,thereisnomodelforwhatasalvagedverses

un‐salvagedLVTshouldlooklikeorifasitewaslostinbattleorsimplydepositedin

2‐8

thewaterpost‐battle.TheamphibiousnatureofLVTsyieldsthepossibilitythatthe

craftmyhavebeencatastrophicallylostonshoreandthendiscardedinthewater.

TheuniquenessoftheLVT’samphibiouscapabilitiespresentsachallengefor

siteinterpretationbythemaritimearchaeologist.Archaeologicalandhistorical

researchcombinedwithprocessanalysiscanprovideamorecompletepictureof

thesignificanceofLVTsusedintheBattleofSaipan.Theperceivedthreatstothe

vehiclesbytheJapanesedefenderscalledforthevehiclestobemodifiedpriorto

battleandprocessanalysishasthepotentialtoexplorethiscourseofaction.

ProcessanalysisoftheLVT(A)‐4inTanapagLagoonwillalsohelpdetermine

ifthissitewasacatastrophiclossordeliberatediscard.Historicalresearchwill

provideanexplanationconcerningthissite’sexistence;archaeologicalresearchwill

provideinsightintothemodificationandperceivedweaknessinvehicledesignby

thosewhooperatedthem.Byusingtheideaofpre‐impactthreattoevaluatethe

situationthroughthesoldiers’eyesitispossibletounderstandwhythese

modificationsweremade.Finallythroughmorehistoricresearchthesignificanceof

thesemodificationswillbedemonstratedthroughtheiradaptationtothedesignof

laterproductionmodels.

Chapter3

HistoryandArchaeologicalLiteratureReview

3‐1

Introduction

“NoAMTRACSnooperation”

GeneralHolland“HowlingMad”Smith

Modernamphibiouswarfareisnotpossiblewithouttheinnovative

technologicaladvancesmadeduringWWII.TheSolomonIslandscampaign,inthe

Pacific,sawtheneedfornewvehiclescapableofdeliveringtroopsandcargowhere

traditionalwheeledvehiclesandboatswereunabletotravel.Thesevehiclesneeded

tobecapableofnotonlytravelingthroughthewaterbutalsoacrossshallowand

sometimesexposedfringingreefs.ThesolutiontothisproblemwastheAmphibious

TractoralsoknownastheAmtracorLandingVehicleTracked(LVT)(Barker2004,

p.3).Thischapterwilldiscussthearchaeologicalresearch,whichhasbeen

conductedtodateonLVTsandpresentacompletehistoryoftheLVTfromits

inventiontoitsuseinthePacific,Saipanandafterwards.

LiteratureReview

ThoughmuchworkhasbeendoneconcerningsubmergedWWIIsites,

archaeologicalinvestigationsofAmtracshavebeenmostlylimitedtoresource

inventoryandsiteassessments.ThomasandPrice(1980,p.33)mentionapossible

LVTintheirCulturalResourcesReconnaissanceReportfortheSaipanSmallBoat

Harbor,CommonwealthoftheNorthernMarianaIslands,butdonotmentionany

archaeologicalinvestigationsbeyondsiteidentification.Carrelletal(1991)

mentionthelocationofafewLVTsduringtheNationalParkServicesubmerged

culturalresourceassessmentofMicronesia;theLVTswererecorded

3‐2

archaeologically,howeverCarrellacknowledgesthefactthatnotmuchisknown

aboutLVThistoryconcerninglossordisposal(Carrell1991,p.118).

VanTilburgmentionsseveralLVTsinU.S.NavyShipwrecksinHawaiian

Waters:anInventoryofSubmergedNavalProperties(2003).TheseLVTsmayhave

beendumpedaftertheMay1944WestLochexplosion,whichdestroyedequipment

intendedfortheInvasionofSaipan.TheseLVTsareidentifiedasLVT‐1sandLVT‐2s

andarelocatedindepthsofwaterrangingfrom1197‐1200ft(364.85‐609.6m)

(VanTilberg2003).

In2004,anLVT‐4waslocatedburiedonGuam.Thesitewasinterpretedas

beinganLVTthatforsomereasonstoppedrunningaftermakingittoshoreduring

theInvasionofGuam(Miller2004).Duringreclamationprojectsin1944theLVT

wasusedaslandfill(Miller2004).Nomentionoffieldexpedientarmor

modificationswaslocated.

In2007SteinberginvestigatedasubmergedLVT‐4inDarwinHarbor,

Australia.ArchaeologicalinvestigationconfirmedthesitewasaLVTandhistorical

researchrevealeditwaspurchasedasmilitarysurplusinordertoactasapassenger

ferrytoMandorahBeach.TheLVTsankwhilebeingtowedandneversawserviceas

aferry(Steinberg2007,p.9).

SoutheasternArchaeologicalResearchInc.(SEARCH)conductedremote

sensingsurveysofSaipan’swesternlagoonsforculturalmaterialrelatingtothe

InvasionofSaipan(Burns2008,p.84).ThesurveyrevealedanAmtrakinTanapag

Lagoonhowevernoarchaeologicalinvestigationswereconductedbythegroup

3‐3

beyondidentification(Burns,2008p.84).PartsofanAmtracwerealsolocatedin

GarapanLagoonwithnofurtherinvestigationsconducted.

In2009,SmithresearchedaLVT(A)‐4knowntohavebeenlostoffof

StocktonBeachNewSouthWales,Australiaon8March1954at02:00(Smithet.al.

2009,p.6:SmithandWard2009,p.7).FiveLVT(A)‐4swerelostduringatraining

exercise,howeveronlyonehasbeenlocated(SmithandWard2009,p.7).Historical

accountsreportthattheweathertookaturnfortheworse,causingsomeofthe

LVTstosinkandotherstocapsizeinheavysurfwhiletryingtomakeittosafety.To

datenoworkhasbeenpublishedconcerningarchaeologicalinvestigationsofthe

knownsite.

MostsecondarysourcesdevotedtotheBattleofSaipanonlybrieflymention

theLVTsroleduringtheinvasion.Theseaccountsrefertothevesselsferrying

troopstobattlebeforefortheauthorsfocusonthegroundwarfare(Brooks2005,p.

136:Goldberg2007,pp.57‐75).Someaccountsgointomoredetailbyfocusingon

thenegativeaspectsofthecraftsuchas,itwasaslowandcumbersomemachineand

thearmorwasconsideredtoothin(Chapin1994,pp.1‐2:Hardwood1994,p.10:

Rottman2004,p.17).

FortunatelythereareafewpublicationswrittenbythosewhooperatedLVTs

duringtimesofwarandsawfirsthandtheuniquecapabilitiesthevesselspossessed

(Croizat1992:Bailey1976:Barker2004).Theseprimarysourcespointoutthatthe

flawsintheLVT’sdesignwerenotlostuponthecrewswhooperatedthemachines

anditisthesecrews’ingenuitythatledtothevehiclesbeingmodified(Mesko1993:

3‐4

Bailey1976:Barker2004).ThesemodificationsdirectlyinfluencedfutureLVT

designs,thusassistingfuturetroopsinbattle.

WorksbyBailey(1976)andBarker(2004)givefirsthandaccountsofLVT

crewsconductingmodificationstoLVTsbeforeengaginginbattle.Thisinformation

ledtoalistofitemstobeinvestigatedontheTanapagLagoonLVT(A)‐4.Itemssuch

asboilerplateaddedtotheupperandlowerbowofthevehicle,aswellasvision

portscutintothecabwerementionedinthesesources.Itwasalsolearnedthat

crewscoveredtheupperdeckportionsoftheirvehicleswithsandbags(figure3‐1).

SandbagshelpedstopbulletsfrompenetratingtheLVTandaidedinpreventing

magneticminesfrombeingattachedtotheportionsofthevesselthattheycovered.

ResearchinghistoricalaccountsofWWIIproducedaMasterofMilitaryArt

andSciencethesisbyMatthewBoalentitledFieldExpedientArmorModificationsto

USArmoredVehiclesfromtheU.S.ArmyCommandandGeneralStaffCollege(Boal

1994).Boaldefinesthemodificationsdonebycrewspriortoengagingtheenemyas

“fieldexpedientarmormodifications.”Inthisstudy,Boaldocumentsthecrewlevel

battlemodificationsofarmoredwarmachines,howevernomodificationstoLVTs

werenoted.

3‐5

Figure3­1:Imageshowingexpedientfieldmodificationsofusingsandbagsandextraarmor

aroundtheturrettop.(Photo:DepartmentofDefense[USMC]).

Roebling’sAlligator

AsessentialastheAmtracwasinthewareffortitdidnotbeginitscareerasa

militaryvehicle. DonaldRoeblingdesignedthevehiclehecalledthe“Alligator”for

rescuing hurricane victims in the Florida Everglades (The United States Marine

CorpsAir‐GroundMuseum1997,p.3). Mr.RoeblingbegandesigningtheAlligator

in1935afterwitnessingthedestructionandlossoflifecausedbyahurricane. He

believed amachine capable of traveling throughFlorida’s swamplands could save

manylives.

3‐6

Figure3­2:LVT­1prototypebeingfield­tested.(Photo:http://www.olive­

drab.com/images/id_roebling_alligator_03_700.jpg).

RoeblingconstructedtheAlligatorwithanaluminumhull,whichgreatly

aidedbuoyancy.Thevehiclewas24feetlong(7.32meters)witha92‐horsepower

Chryslerenginepoweringthetracks.Thetracksmountedboltoncleatsknownas

grousersthatactedaspaddlesinthewaterandprovidedtractiononland.The

originaldesignofthegrouserwasaflatmetalcleatthatrandirectlyacrossthetrack.

TheAlligatorwascapableofatopspeedof25milesperhour(40.23Kilometersper

hour(kph))onlandand2milesperhour(3.22kph)inthewater(Mesko1993,p.4).

3‐7

Unhappywiththevehicle’sperformance,Roeblingbegantomodifyhis

design.Heexperimentedwithdifferentenginesandstrippedunnecessaryweight

fromthevehicleandalsovariedthelengthandwidthoftheAlligator.Hefoundthat

thegrouserdesignwasthekeytospeedandefficiencyinthewater.Roebling’sthird

prototypefeaturedarevisedsuspensionthatcausedlessdraginthewaterandthe

grouserwaschangedtoaslightlycurvedshapethathemounteddiagonallyacross

thetrack.Thisnewgrouserdesignandrevisedsuspensionyieldedatopspeedof

only20milesperhouronland,butspeedinthewaterincreasedto8.6milesper

hour.ThisrevisionoftheAlligatorcaughtnationalattention(Bailey1986,pp.37‐

38).

LifeMagazine(Figure3‐3)rananarticlefeaturingtheAlligatorinOctober

1937(Life1937,pp.94‐95).ThisarticlesparkedaninterestwiththeU.S.military

andinvestigationsintothefeasibilityofthevehicle’suseinmilitaryapplications

began.InitiallyRoeblingwasnotinterestedinproducingvehiclesforthemilitary,

asheenvisionedtheAlligatorforthepurposeofsavinglives.Ittooksome

convincingbymilitaryleadersthatindeedhisvehiclewouldbeusedtosavelivesof

AmericansoldiersandMarineswhowouldbesenttowarinthePacific.

3‐8

Figure3­3:LifeMagazinearticlefeaturingtheAlligator.(LifeMagazine1937,p.94).

3‐9

LVT­1

MilitaryproductionmodelsofRoebling’sAlligatorarecommonlyreferredto

asamphibioustractors,AmtracsandLandingVehicleTracked(LVT).Thefirst

productionmodelwasdesignatedtheLVT‐1bythemilitary(Bailey1986,p.41).

TheLVT‐1designconsistedofallsteelconstructionandthedriver’scabwasslanted

backproducingalowerprofile.Thevehiclewaskeptafloatbyaircontainedin

sponsonsonbothsidesofthevehicle.Ithadasinglepropulsionsystemconsisting

oftracksmountedontheportandstarboardsides.Thetracksrotatedonarigid

suspensionsystemmountedaroundthesponsons.TheengineusedintheLVT‐1

wasa150‐horsepowerHercules.Theengineturnedadriveshaftconnectedtothe

transmission,whichrotatedthedrivesprocketsthatcontrolledthetracks.Steering

thevehiclewasaccomplishedthroughtheuseoftwocontrolsticks.Thesticks

operatedthetracksindependently,whichgavethevehicletheabilitytoturn.By

havingonetrackmovingforwardandtheotherinreverse,theLVTwascapableof

turninginitsownlength.Thetracksandsuspensionsystemwereessentiallythe

sameastheAlligatorandconsistedofareardrivesprocketmountedtothehullwith

anidlerblockmountedforwardintheupperleftportionofthehull.Theidlerblock

maintainedtensiononthetrackasitmovedacrosstherigidsuspension(Bailey

1986,p.43).

AfteraseriesoftestsandmodificationstotheconstructionoftheAlligator,

theSecretaryofDefenseawardedacontracttoRoeblingforaninitialorderof100

LVTsin1941,andquicklyincreasedthecontracttoanadditional100(Mesko1993,

p.5).Oncethevehiclesreachedmilitarycommands,crewsrealizedthat200LVTs

3‐10

wasnotenoughandadditionalorderswereplacedresultingintheproductionof

1,225vehiclesdistributedtotheMarineCorps,U.S.ArmyandAlliedforces(Mesko

1993,p.5).Roeblingdidnothavethecapacityforlargescalemanufacturingathis

workshop,sohepartneredwiththeFoodMachineryCorporationlocatedin

Clearwater,Floridainordertomeetthedemand(Bailey1986,p.41).

Thefirstalterationtothedesignspecifiedbythemilitarywasinchangingthe

all‐aluminumconstructiontothatofsteel.Militarythinkersdidnotbelieve

aluminumtobeastrongenoughmaterialfortheharshconditionsofextended

militaryuse(Metz1986,p.4).Aluminumwasalsoarelativelynewmaterialand

fabricationprocesseswerestillbeingdeveloped(UnitedStatesMarineCorpsAir‐

GroundMuseum1997,p.6).Anotherchangethemilitarywantedwasanewtrack

design.Itwasthoughttheoriginaltrackwasnotstrongenoughforcontinuedusein

seawaterandsand(Bailey1986,p.59).

TheLVT‐1was21ft.6in.long,9ft.10in.(2.77m.)wide,and8ft.2in.(2.5

m.)tall(Bailey1986,p.43).Ithadthecapacitytocarry4,500pounds(2,041kg.)of

cargo120miles(193.12km.)onlandand50miles(80.47km.)inthewater(Mesko

1993,p.7).Constructingthevehicleoutofsteelcausedareductioninspeeddueto

theaddedweight.Theall‐steelLVThadamaximumspeedof12mph(19.31kph)

onlandand6to7mph(9.66‐11.27kph)inthewater(Bailey1986,p.43).

TheLVT‐1sawitsfirstcombatdeploymentduringtheSolomonIslands

campaign(Metz1984,p.4).Originallyintendedasalogisticalsupportvehiclesolely

forthedeliveryofcargo,militaryleadersquicklyrealizedtheversatilityofthese

vehicles.AtthelandingsonGuvutu‐Tulagi,acrossfromthemainislandof

3‐11

Guadalcannal,militaryplannersexpressedconcernaboutgettingtroopsacrossthe

FenaruRiver.ThesolutionprovedtheversatilityoftheLVT.Engineersfabricateda

bridgefromscrapmaterialsonboardship.Thebridgewasthenmountedacrossthe

topoftwoLVT‐1s.TheLVTscarriedthebridgetotheriver,pulledalongsideeach

otherandactedaspontoonssupportingthebridgewhiletheinitialassaultforce

crossed(Bailey1986,p.53).

Beinganewtechnology,theLVT‐1sufferedfromshortcomingsinthedesign.

Oneoftheseflawswasthetrackandsuspensionsystem(Mesko1993,pp.7‐9).

Overloadingthevehiclecombinedwithsandandseawatercausedthebearingsto

seize,whichmeantthetrackwasbeingdrugaroundthetrackguidesbythedrive

sprocketalone.Anotherseriousissuewastheslowspeedoftheamphibians.The

Navy’sBureauofShipswantedthevehicletoobtainspeedsofatleast15milesper

hour(24.14kph)onlandand8milesperhour(12.88kph)inthewater(Bailey

1986,p.59).

LVT­2

FoodMachineryCorporationreengineeredthetrackandsuspensionsystem,

whichfeatured11rubbertiresonrubberspringsmountedtobothsidesofthe

vehicleatthebottomofthepontoons(Mesko1993,p.9).Thetrackbearingswere

hermeticallysealedtopreventsandandwaterfromentering.Thenewdesign

incorporatedthefrontdriveandpowertrainoftheM3A1lighttank,whichallowed

mudandotherthingstobediscardedbeforethetracklinksreachthedrive

sprockets.ThenewenginewasmorepowerfulandreliablethanthatoftheLVT‐1.

3‐12

Fouruniversaljointswerealsoaddedtothedriveshaft,whichranthroughthe

centerofthecargobaytopreventdamageinthecaseofhulldistortion(Bailey1986,

p.59).

Perhapsthegreatestcontributionofthereengineeringwasthenewgrouser

design.FoodmachineryCorporationtestedover100grouserdesignsonmodel

tanksandselectedthebestdesign(Metz1984,p.4:Mesko1993,p.9:Bailey1986,p.

57).Thegrouserchosenturnedouttobea“W”shape(figure3‐4).Thenewgrouser

didnotcauselateralpressureandwearwhileinthewaterthattheoriginalgrouser

did(Metz1984,p.4).

Figure3­4:Illustrationofgrouserdesignchange.(Image:Mesko1993,p.12).

3‐13

Thenewdesign,designatedtheLVT‐2“WaterBuffalo”,was26ft.2in.(7.97

m)long,10ft.8in.(3.25m)wideand8ft.8.5in.(2.66m)tall(Mesko1993,p.11).

Designersextendedthebow,loweredthedriver’scabandlengthenedthebody

givingtheWaterBuffaloamorestreamlinedappearance.Ithadacargocapacityof

6,500pounds(2,948.35kgm)or24troops(Mesko1993p.9).The7‐cylinder200

horsepowerContinentalradialenginepropelledtheLVT‐2atatoplandspeedof20

milesperhour(32.19kph)andreachedspeedsof7.5milesperhour(12kph)inthe

water(Bailey1986,p.59).Thereweremountsforone.50calibermachinegunand

four.30calibermachinegunsbehindthecabandaroundthecargoarea.Two

thousandninehundredandsixty‐twoLVT‐2swereproducedbetween1943and

1944(Mesko1993,p.9).EarlyproductionmodelsoftheLVT‐2thatwereintended

forassaultpurposeswerefittedwitharmorkitstobeweldedonbythecrews,

howeverthesemodelsdonotcarrythearmored(A)designation(Bailey1986,p.62;

Mesko1993,pp.13).

LVT(A)­2

ThemanufactureralsoproducedlaterLVT‐2productionmodelswitharmor

aroundthecabandbowareas(figure3‐5).TheseLVTsweredesignatedtheLVT

(A)‐2andwerethefirstLVTstoreceivethe“A”designationsignifyingthatthey

werearmored.Thearmoraroundthecabwas.5in.(12.7mm)thickandonly.25in.

(6.35mm)thickaroundthehull.Insteadofplexiglasswindowsthearmored

versionhadanarmoredhatchthatdroppeddowntoprotectthedriver.Engineers

fittedthetopofthecabwithtworotatingperiscopestoallowthedrivertoseewhile

3‐14

incombat.Self‐sealinggasolinetankswerealsoaddedtotheassaultversion.The

addedweightofthearmoredversionscausedadecreaseincarryingcapacityto4,

500pounds(Mesko1993,pp.9‐13).FoodMachineryCorporationproduced450

LVT(A)‐2sanddeliveredthemtotheArmy.

Figure3­5:ComparativedrawingofLVT­1andLVT­2.(Image:Mesko1993,p.9).

3‐15

Figure3­6:DesignchangesofLVT­2andLVT(A)­2.(Image:Mesko1993,p.13).

LogisticsInvolvedwithLVTDeployment

Marinetroopswerecarriedintobattleaboarddeepdraftedtrooptransport

ships(Grosvoner1944,pp.1‐30).Theseshipsalsocarriedthetraditionallanding

craftwiththebigforwardrampknownasLandingCraftVehicle,Personnel

(LCVP)(Grosvoner1944,pp.1‐30).Theliftingarmsonthesetransportshipswere

notstrongenoughtolifttheLVTssotheywereloadedaboardshipsknownasLSTs

(LandingShip,Tank).LSTsareshallowdraftvesselswithlargebowdoorsthat

3‐16

allowtheshiptopullintoshallowwater,openthebowdoors,andhavethevehicles

theyarecarryingdriveout(Grosvoner1944,pp.1‐30).Marinesclimbeddown

cargonetsstrungovertheships’sidestoLCVPs,whichferriedthemtothewaiting

LVTs.Thewholedeploymentrequiredtwohours(Grosvenor1944,pp.1‐30:Bailey

1986,p.86).

Tarawa

ThefirstcombatuseoftheLVT‐2wasintheBattleofTarawaintheGilbert

Islands(Croizat1992,pp.88‐89).ThecaptureoftheSolomonIslandsgavethe

UnitedStatestheabilitytoopenanoffensivedrivethroughtheislandsoftheCentral

Pacific.TheAmericanssoughttocapturetheNorthernMarianaIslandsofSaipan,

Tinian,andGuameffectivelyseveringtheJapanesemainlineofcommunications

(Brooks2005,p.54).ThefirstobjectiveinthisoffensivewasTarawaAtollandits

airfieldsonBetioIsland.Betiopresentedanewproblemfortheassaultforces,a

fringingreefwithnoknownopeningsandsubjecttodrastictidalchanges.Ifthetide

wasouttraditionallandingboatswouldnotbeabletodeliverthetroopsashore,

thusleavingthemstrandedonthereeftowadeacrossthelagoonunderheavy

enemycrossfire.ThisfactledtoGeneralHollandSmith,thelandingforce

commander,tellingAdmiralKellyTurner,theAmphibiousForceCommander,“No

Amtracsnooperation”(Smith1989,p.20).ThissimplestatementledtotheLVT

beingdeployedasanamphibiousassaultcraftandwithitcameasignificantchange

inhowtheNavyandMarinesconductedamphibiousoperations.

3‐17

LVT‐1sandLVT‐2swerebothusedintheinvasionsatTarawa(Croizat1999,

pp.96‐97).ThecrewsmodifiedtheirLVT‐2sinSamoapriortobeingdeployedto

Tarawa(Croizat1992,p.87).ThemodificationsinSamoaconsistedofmountinga

26in.(66,04cm)by40in.(101.6cm)pieceof3/8in.(.95cm)boilerplatetothe

frontofthecabofthe50LVT‐2s.Crewsalsomounteda.50caliberandtwo.30

calibermachineguns;one.30calibermountednearthesternofthevesselwhilethe

othertwogunsmountedjustbehindthecab(Baileypg84‐91).

Seventy‐fiveolderLVT‐1sfromthe2ndAMTRACBattalionlocatedinNew

Zealandwentthroughsimilarfieldexpedientarmormodificationspriorto

rendezvousinTarawa.ArmamentoftheLVT‐1sincludedtwo.50caliber

machinegunsmountedaftofthecabandone.30calibermachinegunnearthestern

ofthevessel.Armorplatingmeasuring.25in.(6.35mm)thickwereaddedtothe

sidesandfrontofthecabalongwitha1.5ft2(45.72cm2)armorplateattachedto

theinsideofthecabtoprotectthedriver(Bailey1986,p.84).Twolargegrappling

hookswerealsoattachedtothesternwiththeintentionofbeingusedtopullup

Japanesedefensivewire(Bailey1986,p.84)Allofthesemodificationsaddedweight

totheLVTsandresultedinareductionofspeed.

LVT(A)­1

FoodMachineryCorporationaddeda37mmgunturretfromtheM5A1Stuart

lighttanktotheWaterBuffalo,whichresultedintheLVT(A)‐1(Mesko1993,p.21).

TurretedversionsoftheLVTsarealsoknownasAmtanks.Inadditiontothe37mm

gun,theaftportionoftheLVT(A)‐1possessedtwoguntubsmountinga.30‐caliber

3‐18

machineguneachonscarfrings(figure3‐7).Laterproductionmodelschangedthe

ringmounttoMark21mountsandaddedaballmounted.30‐calibermachinegunin

thecabattheradiooperator’sseat.FoodmachineryCorporationproduced510LVT

(A)‐1sin1944(Mesko1993,pp.21‐24).

Figure3­7:ComparativelinedrawingofLVT­2andLVT(A)­1.(Image:Mesko1993,p.21).

3‐19

MarshallIslands

ThenextstepinstoppingtheJapaneseexpansioninthePacifictheaterwas

theMarshallIslands(Croizat1999,pp.96‐97).Thisislandchainconsistsofmany

coralatollsallsurroundedbyshallowfringingreefs.LVT‐2sandthenewAmtank

theLVT(A)‐1madetheirdebutintheassaultonthetinyislandsoftheatolls(Bailey

1986,p.106).TheinitiallandingsinKwajaleinAtollatMelluandEnnuebingIslands

followedthesameloadingproceduresasTarawa,howeverforsubsequentlandings

theplanchangedtotransportingtroopsinLCVPsovertotheLSTscarryingtheLVTs

(Croizat1989,p.70).Thetroopsthenclimbedupcargonetsstrungfromthesides

oftheshipswheretheywouldloadintotheirassignedLVTs.Onceloaded,theLST’s

bowdoorswouldopenandtheLVTswouldmakeforthelineofdeparture(Croizat

1989,p.70).

TheMarinescontinuedtousetheirLVTstogaincontrolofthenorthernareas

ofKwajaleinAtollwhiletheArmyworkedtheirwaythroughthesouthernportions

oftheatoll(Bailey1976,p.128).TheArmyusedLVT‐2s,LVT(A)‐2s,andLVT(A)‐

1stocompletetheirobjectives(Bailey1976,p.128).LVTswerethenrelegatedto

logisticaldutiesaftertheinitialinvasion(Bailey1976,p.130).

MarianaIslands

ThefirstobjectiveintheMarianaIslandswassecuringtheislandofSaipan.A

successfulinvasionofSaipaneffectivelyplacedthemainlandofJapanwithin

strikingdistancesofU.S.B‐29bombers(Rottman2004,pp.7‐8:MinistryofDefense

1995,p.95).JapanesemilitaryleadersconsideredtheMarianaIslandsastheirlast

3‐20

lineofdefenseandfoughttopreventtheislandfrombeingseizedbytheAllies

(Brooks2005,pp.101‐226).AsWWIIcontinued,FoodMachineryCorporation

continuedtoredesigntheLVT.Newmodelswerecomingofftheassemblylineand

Saipanwouldbetheirtestingground.

LVT­3&LVT­4

Borg‐WarnerwasawardedacontracttoproducetheLVT‐3butproduction

problemsdelayedtheLVT‐3fromenteringthewaruntiltheOkinawacampaign.

TheLVT‐4wasthenewcargocarryingdesignandwasthesameastheLVT‐2from

thebowtothedriverscab.Engineersmovedtheenginefromtherearofthecargo

areatojustbehindthedriversseat(Metz1984,p.5).Thismoveallowedthedrive

shafttoberundownthecenterofthecargoareaandfreedmuchneededcargo

space.Designersincorporatedarearramptofacilitateloadingandunloadingcargo

(Mesko1993,p.14).Therampalsomeantthattroopsnolongerhadtoexpose

themselvestoenemyfirewhileclimbingoverthesides.Theredesignincreasedthe

carryingcapacityby2,500pounds(1,133.98kgm)allowingjeepsand105mm

howitzerstobedelivered.FoodMachineryCorporationproduced8,351LVT‐4

WaterBuffalos(Mesko1993,p.14).Noarmoredversionswereproducedbutarmor

kitsweremadeavailabletoforcestoaddandremoveasmissionsdictated(Mesko

1993,pm.14).

3‐21

Figure3­8:LinedrawingofLVT­3andLVT­4.(Image:Mesko1993,p.17).

LVT(A)­4

FoodMachineryCorporationalsoproducedanewAmtank,theLVT(A)‐4.

TheLVT(A)‐4isbasicallyaLVT(A)‐1thathasbeenslightlyextendedinorderto

mounta75‐mmhowitzerturrettothetop(Mesko1993,p.27).Theturretofearly

productionmodelspossessedasinglering‐mounted.50calibermachinegunwhich

designerslaterchangedtotwopintelmounted.30calibermachinegunsandaddeda

ballmounted.30calibermachineguntothecabattheradiooperator’sseat(figure

3‐22

3‐9)(Mesko1993,pp.27‐28).Thesemodificationsbecameknownasthe“Marianas

Model”butnochangeinmodeldesignationoccurred(Mesko1993,p.30).

Thehighvelocityroundofthe37mmhowitzerwaseffectiveagainstenemy

armorbutlackedtheabilitytodestroyJapanesepillboxesandbunkers(Mesko

1993,p.27:Collier1949,pp.54‐55).The75mmhowitzerprovidedahigh

trajectory,highexplosiveshellintendedtodestroyheavilyfortifiedJapanese

positions.Thisnewartillerywaswelcomedbythetroops,howeveritpossesseda

majorflaw;theturretwasnot,thuscoveredmakingitvulnerabletoenemy

grenadesandmortars.Thelackofcoveringalsolefttheturretmachinegunner

exposedtoenemyfiremakinghimaprimetarget(Bailey1986,pp.163‐182).

Figure3­9:ComparativelinedrawingofLVT(A)­1andLVT(A)­4.(Image:Meskop.27).

3‐23

CrewsbeganfieldexpedientmodificationstotheearlyproductionmodelLVT

(A)‐4sassoonastheyreceivedtheminpreparationfortheInvasionofSaipan

(Barker2004,p.253).Modificationsincluded:addingarmorplatingaroundthe.50

calibergunstohelpprotectthegunner,adding.30caliberco‐axialmachinegunsto

thecabinfrontoftheradiooperator’sseatandaddingarmorshieldstotheforward

portionoftheturret(Bailey1986,pp.163‐168).Allofthesefieldexpedient

modificationshadthegoalofprolongingthelifeofthecrewandthevessel.

Saipan

TheislandofSaipanissubstantiallylargerthantheatollislandsofthe

GilbertsandMarshalls.Thelargergeographicareacalledforamassiveinvasion

forceandthepresenceoffringingreefsdemandedtheuseofLVTs.Theassaultplan

calledfortheuseof600troop‐carryingLVTsprecededby136Amtanks(Rottman

2004,pp.44‐54).ForthisoperationthetroopswereshuttledtoLSTscarryingthe

LVTssixdaysbeforetheinvasion.Thismovementexpeditedformingthelanding

forceonthedayoftheinvasion.Onthedayoftheinvasion47LSTsassumedtheir

positionsnearthefringingreef,1,000yards(914.4m)fromthelineofdeparture

(Chapin1994,pp.1‐3).TheLVTsdisembarkedandformedupattheirrespective

landingzoneswiththeAmtanksprovidingfiresupportfromthesides.Fourwaves

hitthebeachesattimedintervalsbeginningat080515June1944(Rottman2004,

pp.44‐54).RoughseascapsizedmorethanafewLVTsonthereefbutthemajority

madeittoshore(Chapin1994,pp.3‐4:Rottman2004,pp.44‐54).

3‐24

TheAmtracsweretoreachtheirdesignatedlandingbeachesandmove200

yardsinlandbeforeunloadingtroopsandthenmovefurtherinlandtowhatwas

calledthe0‐1line(Chapin1994,p.4).Thisallowedthebeachestoremain

unclutteredforthearrivalofsubsequentwavesoflandingforces.

TheruggedterrainofSaipanprovedtobemorethanachallengeforthe

LVTs.Debrisfrompreviousairstrikesandnavalbombardmentscoupledwiththe

ruggednatureandthickforestsofSaipanpreventedtheLVTsfrompenetratingto

theplanned1200‐1500yds(457‐640m)inland(Rottman2004p.51:Chapin1994,

p.4).Mostdisembarkedtheirtroopsonthebeachunderheavyfire.

Aftertheinitialassault,commandersemployedcargoLVTsinawiderangeof

missionsincluding:shiptoshoresupplydelivery,evacuationofwoundedto

hospitalships,runsinlandtosupplydumps,assistingUnderwaterDemolition

Teamswithblastingaboatchannelthroughthereef,firefightingvehicles,anduse

assalvagevesselsforpushingstrandedlandingcraftoffofthereef(Croizat1953,

p.46).ExperimentswithbridgeheadrampswerealsoconductedbyLVTs.These

rampsconsistedofironsupportswithwoodendeckingchainedtothetopofaLVT.

TheLVTwouldpulluptoaverticalshorelineofupliftedcoral,unchainthebridge

andbackaway(Croizat1953,p.46).Thebridgewouldthenslideoffthefrontofthe

LVTandresultineffectivelywideningalandingzoneandpermittingAmtracsto

gainaccesstoelevatedbeachheads.TheinvasionofTiniansawthesuccessfuluseof

thislandingmethod(Rottman2004,pp.47‐84).

Aftersecuringthelandingbeaches,theSecondMarineDivisionmovednorth

alongthewesternbeachestakingcontrolofGarapanbeforetheymettheArmy’s

3‐25

27thInfantryDivision.LVT(A)‐4sfromtheMarine’s2ndArmoredAmphibian

BattalionwereusedasartillerytodestroyJapanesegunslocatednearthewaterin

thetakingofGarapan(Chapin1994,p.28).AftercapturingGarapan,theSecond

MarineDivisionwasplacedintoreservestatusandtheArmyandcontinuedtopush

beyondGarapanandnorthwardthroughTanapagHarbortoTanapagwherethey

weretomeetupwiththeFourthMarineDivision(Rottman2004,p.68).Atthis

pointitisnotedthatsomeamphibioustractorsweresentformaintenanceand

repairsinpreparationfortheamphibiousassaultonTinian(Bartholomees1948,

pp.7‐8).ThesalvagingofLVTcomponentsisnotspecificallymentioned,butitis

reasonabletoassumethattheLVTsthatwerenotcapableofbeingrepairedwere

strippedofallusablepartsinordertorepairotherLVTstooperationalstatus.

Gyukysai

Onthenightof7July1944GeneralSaito,thecommandingofficerofthe

JapanesetroopsonSaipan,orderedalarge‐scalebanzaiattack.Itisrumoredthat

thisattackwasactuallyanactknownasagyukysai(Brooks2005,p.217).Gyukysai

literarilymeans,“breakingthejewel”andthisisareferencetothethreevirtuesof

Japaneseculture:

1) TheSwordsymbolizestruewisdomofdecisionsmade

decisively.

2) TheMirrorrepresentstheabilitytoseethings,asthey

aregoodorbadinordertorecognizetruejustice.

3‐26

3) TheJewelcharacterizestheJapanesebeliefthattheysee

themselvesasgentileandpiouspeople(Brooks2005,

p.217).

BreakingthejewelforallintentsandpurposesmeantallJapaneseregardless

ofage,sexorsocialstandingmustembraceaviciousnessthatwouldmakethe

Emperorunbeatableagainstallodds.TheEmperorhimselfistheonlyonewhocan

orderagyukysai.However,GeneralSaitotoldhisforcesthattherewasnolongera

distinctionbetweenJapaneseciviliansandtheJapanesemilitary,implyingthe

gyukysaihadbeenorderedandallJapaneseontheislandwherebeingorderedto

fighttheU.S.invaders(Brooks2005,p.217).

Duringthedaysleadinguptothegyukysai,LVT(A)‐4sarenotedinhistorical

documentstohaveprovidedartillerysupportduringthetakingofGarapanpriorto

U.S.forcesmovingontoTanapag(Chapin1994,p.28).LVTusebecomesunclearin

thehoursleadinguptothefinalJapaneseassault.TheU.S.forcesonTanapagPlains

couldhearthegatheringofpeopleinthedarknesssingingsongsandshoutingwhile

drinkingsake(Chapin1994,p.31).At03:55onJuly7,1944theJapanesemounted

anattackontheU.S.positionsjustsouthofTanapag(G21944,p.50,Headquarters

FourthMarineDivision1944,p.35).

Lowonsupplies,someJapanesearmedthemselveswithknivestiedtosticks

andinsomecasesjustpointedsticks(Bartholomees1948,p.6).TheJapanese

gatheredinthetreelineandcomplexnetworkoftrenchesforwardoftheAmericans

positionwhichofferedcoverandconcealmentfromU.S.machinegunposts.The

maingroupofJapaneseattackedutilizingtheapproachrouteofanarrowgauge

3‐27

railwaythatranparalleltothebeachthroughTanapagPlains(Headquarters106

Infantry1944,p.23).Thisallowedthemtheabilitytodistributethegreatestamount

ofpeopleinthequickesttimepossibletoeffectivelyoverruntheU.S.lines.Thegoal

ofeveryJapanesesoliderthatdaywastotake7U.S.livesforeveryJapanesedeath

(Brooks2005,p.217).TheU.S.positionswerequicklyoverruninthechaos

(Headquarters106Infantry1944,p.22).Thebattlebetweenthetwoopposing

forceswasinsuchclosequartersthatbodiesoftheJapanesedeadpiledupinthe

fieldsoffireofU.S.machinegunnersandinsomecasesspilledintotheirpositions

(Chapin1994,pp.32‐33).HandtohandcombatquicklybecamenecessaryasU.S.

troopsfellbacktomoresecurepositionssouthtowardsGarapan(Chapin1994,p.

34).U.S.forceswerepushedback3,000yards(2,743meters)beforetheywereable

toholdoffthelastofgeneralSaito’sdefenders.Mostofthefightingendedby11:30

on7July1944howevercombatoperationscontinuedthroughouttheday(Rottman

2004,p.68).Intheend4,311Japanesewerefounddeadalthoughsomeoftheseare

accountedforfrompreviousU.S.bombardments.Atotalof451U.S.troopswere

deadand594woundedinthebattle(Rottman2004,p.68).Itshouldbenotedthat

officialaccountsandotherhistoricaccountsdifferonthedatesofthisattack,

probablyduetothelocationofauthorswhowroteaboutthesubjectoneitherside

oftheinternationaldateline.

TheRoleofLVTsDuringtheBattleofTanapagPlains

LVTshadbeenpulledoffthefrontlinespriortotheattackformaintenance

andgeneralrepairsbeforetheplannedinvasionofTinian.ItisuncleariftheLVT

3‐28

(A)‐4swereincludedinthismaintenanceoriftheycontinuedintheirroleasmobile

artillerysupplementingthetraditionalartillerybatteriesandfightinginthe

swamplandswherethemudwastoothickfortraditionaltanks.Whatisclear

throughthehistoricdocumentsisthatLVTswerecalledupontodeliversupplies

andammunitiontothetroopsfightingonthefrontlinesofTanapagPlainsby

approachingfromthewaterdirectlytothefrontlines(Bartholomees1948,pp.8‐

13).Theyalsoevacuatedcasualtiesviawaterfromtheareaoftheattacktomedical

stationsonreturntrips(Bartholomees1948,pp.11‐13).TheLVT’sabilitytotravel

throughthewaterallowedittocomewithinreachofthefrontlines,without

drawingmuchenemyfire,andprovidedesperatelyneededrelief.

ThelocationoftheLVT(A)‐4inTanapagLagoon,nearwherethisbattletook

place,mayindicatethatLVT(A)‐4swerebeingusedonornearthefrontlinesand

afterbeingdestroyeditwasdisposedofjustoffshore.However,specifichistoric

documentationhasnotbeenlocatedatthistimetolendsupporttothisspeculation.

ItispossiblethattheLVT(A)‐4wassimplydisposedofinarandomlocationafter

beingdisabledinanotherbattleandheavilysalvaged.

TheInvasionofManiagassa(Managaha)Island

On13July1944U.S.forcesstagedwhatisdescribedasaminiatureamphibious

landingonManiagassa(nowManagaha)IslandinTanapagLagoon(Bailey1976,p.

180).Theislandisapproximately250meterswideby300meterslong,surrounded

byshallowreefsandlocatedjustoutsidetheshippingchanneltoTanapagHarbor.

TheislandcontainedanelementofJapanesesoldiersandKoreanlaborers,thus

3‐29

posingathreattoAmericanshipping.Thesoldiersweremanningtheisland’sthree

120mmguns,whichhadbeenknockedoutofactioninpreviousU.S.bombardments

(Rottman2004,p.69).Priortotheinvasion,thetinyislandwasbombardedwith

navalartillery(Bailey1976,p.179).Thesoldiersontheislandhadbeenignored

untilthemainJapanesedefensesonSaipanwereeliminated.Marinesfromthesixth

MarineDivisionattackedtheislandutilizing5LVT(A)‐4sleadingthewayfor25

LVTs(Bailey1976,p.180).Thebattlelastedlessthananhour(Bailey1976,p.180).

OncetheIslandofSaipanwasdeclaredsecure,LVTswereusedtoclearcavesthat

couldonlybereachedbywater(Chapin1994,p.8).

LVTUseAfterSaipan

TheAmtracsandAmtanksoftheMarinesandU.S.Armycontinuedtoprove

theirusefulnessthroughouttheMarianascampaign,theCarolineIslands,

Philippines,IwoJimaandOkinawa(Croizat1989,pp.69‐76).LVTscontinuedto

benefitfromdesignimprovementsforthedurationofWWIIinthePacific.Notlong

afterWorldWarIIendedtheArmedForcescalledtheLVTstobattleinKorea

(Croizat1999,pp.82‐75).ThistimethemilitarycalledupontheLVT(A)‐5(figure3‐

10).

TheLVT(A)‐5isaversionspecificallydesignedtoaddressthemajor

problemsoftheLVT(A)‐4(Mesko1993p.31).TheLVT(A)‐5incorporatesallofthe

modificationsseeninLVT(A)‐4ssuchasbowmountedmachinegunsandtwo

machinegunsmountedontheturret.Themanufacturerraisedthesidesoftheopen

turretandaddedviewportstoboththeturretandcabinordertohelpprotectthe

3‐30

crewinside(Mesko1993,p.31).Theturretwasenclosedandincorporateda

gyrostabilizertoimprovefiringfromthewater,amajorissuewiththeLVT(A)‐4

(Mesko1993,p.31).LVTswereusedagainintheVietnamWar(Croizat1989,p.

75).

Duetothecontinuedstruggletoimprovethisversatilemachine,whatbegan

asahumblecargocarrierisnowtheU.S.military’sAmphibiousAssaultVehicle

(AAV‐7A1)formerlyknownastheLVT‐7(Bailey1986,pp.244‐266:Croizat1989,

pp.70‐76:Croizat1999,pp.74‐74).

Figure3­10:LVT(A)­5earlyandmodifiedversions.(Image:Mesko1993,p.33).

Chapter4

Methodology

4‐1

Introduction

Thischapteroutlinesthedatacollectiontechniquesemployedinthe

investigationoftheLVT(A)‐4locatedinSaipan.Theoriginallocationofthesitewill

beaddressedaswellaseventsthatledtothesitebecomingthefocusofthis

particularstudy.Methodologyconcerningthearchaeologicalsurveyandhistorical

researchwillbeoutlinedandadiscussionoftheabilitytoobtaininformationusing

processanalysisisalsoexplained.

LocatingtheSite

SoutheasternArcheologicalResearchInc.(SEARCH)originallylocatedthe

siteofthisLVTduringanarchaeologicalremotesensingsurveyin2008(Burns

2008,p.84).SEARCHwasundercontractwiththeCNMIHistoricPreservation

Office(HPO)toconductgeophysicalsurveystolocatesubmergedculturalmaterial

inSaipan’swesternlagoons.PhotographsweretakenofthesiteandaGPS

coordinatewascollected;nofurtherinvestigationsbeyondtargetidentification

wereconducted.

InitialInvestigations

InJuly2009,archaeologistsfromFlindersUniversityconductedinitialsite

investigationsontheLVT(A)‐4toassessthefeasibilityofincludingthesiteina

WWIImaritimeheritagetrail.Thisworkwasconductedinpartnershipwithnot‐

for‐profitorganizationShipsofExplorationandDiscovery(SHIPS),towhichthe

NationalParkServiceprovidedfundingthroughagrantundertheAmerican

4‐2

BattlefieldProtectionProgram.Saipan’sHistoricPreservationOffice(HPO),Coastal

ResourceManagementOffice(CRM),andDepartmentofEnvironmentalQuality

(DEQ)providedsupportintheformofsurveyequipmentandboats.Theremainder

ofequipmentandstaffwereprovidedthroughFlindersUniversity.

Theinvestigationconsistedofaninitial30‐minuteevaluationdiveonthe

site.Diversphotographedandnotedkeyfeatures,whilesearchingforunexploded

ordinanceandotherpotentialhazardstoprospectivetrailvisitors.Thesite

evaluationalsoidentifiedlikelynaturalandculturalthreatstothesiteandpossible

locationsforpermanentmoorings.Themarineecologyofthesiteandnearbyreefs

wasalsonotedinordertodeterminethesite’sabilitytoattractvisitors.

ResearchersalsonotedaJapanese“pillbox”orgunemplacementontheshore

directlytotheeastofthesitelocation.

ArchaeologicalMethodology

ThesitewasvisitedoncemoreinJuly2009.Onceallpotentialsite

evaluationswerecompleted,itwasagreedthattheuniquenessofthesitewarranted

furtherinvestigation.Anhourlongdivewasconductedusingbasicmaritime

archaeologicalrecordingmethodsofbaselineoffsets,triangulationandtrilateration

tocollectdataincludingoveralldimensionsandpossibleculturaladaptations.

Researcherstookphotographsoftheentiresiteandadetailedsketchofthesitewas

produced.A65.62ft.(20m)circlesearchwasalsoconductedinordertodetermine

ifthesitewasisolatedorassociatedwithotherculturalfeatures.Thedivewasa

nonintrusivesurveywithnoculturalmaterialbeingremovedordisturbed.

4‐3

HistoricalResearch

In‐depthhistoricalresearchwasconductedconcerningWWIIinthePacific,

andmorespecificallyamphibiouswarfareandtheuseofLVTs.Webpageswere

usedtocollectinitialdatatobeconfirmedbyothersources.Secondarydatawas

collectedfromnumerouspublishedhistoricalsourcesincludingbooksandmilitary

peer‐reviewedjournals.PrimarysourceswerelocatedattheCombinedArms

ResearchLibrary(CARL),whichisassessableonline.CARLpossessesadigitized

libraryofdocumentsconcerningmostU.S.warsbothhistoricandmodern.These

documentsrangefromdeclassifiedmilitaryplans,orders,journalsandafteraction

reportstomonographsandmastersthesesconcerningallaspectsofwarfare.

Alldocumentsandnotesondocumentswerecompiledintoaresearch

databaseutilizingEndNotesoftware(ThomsonReuters2009).Thedatabaseserves

asadigitallibrarybyorganizingallsourcesalphabetically.Bibliographic

informationforeachsourcewasmanuallyenteredandEndNoteallowsforthe

attachmentoffilesorURLsofthesourceaswellasimages,keywordsandresearch

notesforquickreference.Oncethisstepwascomplete,materialsweresearchable

byscrollingthroughthelibraryorbyusingakeywordsearch.Organizing

informationinthiswayallowsforuseinfutureresearchandcompleteaccessto

sourcematerials.

PrimarydocumentsconcerningtheBattleofSaipandescribeindetailhow

thebattlewasfoughtandtheterrainthetroopsencountered.Thisinformationwas

usedtoevaluatetheLVT(A)‐4siteinTanapagLagoonthroughprocessanalysis.

Troopmovementsandobstaclesconcerningthesemovementsaredescribedin

4‐4

numeroushistoricaccountsanddetailedmapsareprovidedaswell(Headquarters

FourthMarineDivision1944:Gugeler1945:Bartholomees1948:Adams1950:

Bailey1976:Croizat1992).Thesemapswereusedtodemonstratethedynamicsof

thebattlefieldandhowterraininfluencedtheuseofLVTs.

Perhapsthemostimportantprimarysourceforunderstandingpotential

processesthatmayhaveaffectedthissiteistheDepartmentoftheArmy’sTechnical

ManualforLVT(A)­4s(1951).Thismanualgivesinstructionsontheoperation,

maintenance,armament,storageandthedestructionofthevehicletoprevent

enemyuse.Ofparticularinterestaretheguidelinesfortheevacuationand/or

destructionofessentialpartsonceanLVTisdisabledincombat.Theseprocedures

includedescriptionsofhowtodisposeoftheLVTbymeansofsinking,burning,

demolitionandgunfire.

OneimportantsecondarysourceconcerningWWIIwasaMasterofMilitary

ArtandSciencethesisbyBoalentitledFieldExpedientArmorModificationstoUS

ArmoredVehiclesfromtheU.S.ArmyCommandandGeneralStaffCollege(Boal

1994).InthisstudyBoaldocumentsthecrew‐levelbattlemodificationsofarmored

warmachines.NomodificationstoLVTswerenotedinthiswork,howeveritgave

credibilitytotheideathatthisLVTpossessedbattlemodifications.

WorksbyBailey(1976)andBarker(2004)givefirsthandaccountsofLVT

crewsconductingfieldexpedientmodificationstoLVTsaspreparationsbefore

engaginginvariousbattlesacrossthePacific.Thisinformationledtoalistofitems

tobeinvestigatedontheTanapagLagoonLVT(A)‐4.Itemssuchasboilerplate

addedtotheupperandlowerbowofthevehicleaswellasvisionportscutintothe

4‐5

cabwerenoted.Itwasalsolearnedthatcrewscoveredtheupperdeckportionsof

theirvehicleswithsandbags.Vehiclemodificationswerenotjustlimitedtothe

exterior,somecrewscoveredtheirradioswithponchosandtheyrolledcondoms

overthemicrophonesasmakeshiftwaterproofing(Barker2004,p.7).

Figure4­1:ImageshowingexpedientfieldmodificationstoearlymodelLVT(A)­4consistingofsandbags,.30cal.bowmachinegunandextendedarmoraround75mmturret.(Photo:

courtesyofKathleenDale).

Forthepurposeofthisstudy,featuresarelistedasanomaliesobservableon

theLVT.Insomecasesafeaturemayrepresentanareaofmissingarmorplates

ratherthanlistingeachindividualplate.Degradationanddamagetothesiteaswell

asmodificationsarealsolistedasfeatures.Thefeaturesarenumberedonthesite

planforeaseofreading.

4‐6

ContinuedArchaeologicalInvestigationsandMethodology

InFebruary2010archaeologistsfromFlindersUniversityandSHIPS

conductedfurtherinvestigationsatthesite.Thepurposeofthissurveywasto

recordthesiteindetailinordertocompleteanaccuratescaledsiteplan,record

fieldexpedientmodificationsandpossibleevidenceofsalvageandgatherany

additionaldatathatmayyieldcluesastowhythisLVTisinitspresentlocation.In

ordertoexpeditethisprocess,scaleddrawingsofaLVT(A)‐4werescannedfrom

WorldWarIIAFVPlans:AmericanArmoredFightingVehicles(Bradford2007,80‐

81).Theexistingportionsofthesitewerethentracedfromtheimagesontomylar

andattachedtoslatessodiverscouldmoreeasilyandaccuratelyrecordwhatthey

wereseeing.

Figure4­2:ExampleoflinedrawingfromBradford2007

Becausethescaleddrawingsandthevehicleswereconstructedinthe

Imperialsystemofmeasurementalldatawasrecordedinfeetandinches.A

4‐7

baselineconsistingofafiberglassreeltapewasattachedtothedeckofthevehicle

acrossthetopoftheporttrack.Offsets,elevationsanddeclinationsweretakento

featuresalongthebaselineusingafiberglassreeltapeandafiberglass‐foldingruler.

Elevationsandwerealsotakentotheseabed.Thisinformationwasintendedtonot

onlyrecordthesiteinitspresentconditionbutalsoaidwithmonitoringthesiteand

theenvironmentinthefuture.

AtotalofthreediveswerecompletedonthesiteduringtheFebruary2010

investigation.Thesediveswerenonintrusiveandlimitedtowhatwasvisibleabove

thesedimentlevel.Noculturalmaterialwasremovedordisturbed.Toaidin

measuringarmorplatingacaliperwasusedtogaugethethicknessofexistingarmor

plates.Allmeasurementswererecordedandtheirlocationnotedontheprepared

slates.

Aftereachdivetheslatesweretransposedintofieldjournals.Thedatawas

thenusedtoproducedetailedscaledrawingsandasiteplan.Allfeaturesofthesite

willbecategorizedandevaluatedbasedonarchaeologicalandhistoricaldata.

PhotographstakenduringboththeJuly2009andFebruary2010investigationswill

beusedtoevaluateandinterpretthesiteasitappearedwhentheresearchwas

conducted.

Inpreparationforphotographs,archaeologistcreatedphotographicscales

andnortharrowsoutofavailablematerials.One‐halfinch(1.27cm)PVCpipingwas

wrappedwithblackelectricaltapeat50cmintervalstocreatea2‐meterphoto

scale.Northarrowswerecutoutofaplasticcuttingboardandweightedwith.5lb

(.23kg)leadfishingweighttapedtotheunderside.Aprofessionalphotographer

4‐8

commissionedthroughSHIPStookphotographsaswellasafewdiverswith

personalcameras.Thephotographerwasmainlyconcernedwithcompositionin

ordertopresentthesitebeautifullytothepublic.Archaeologistspointedoutkey

featurestobephotographed.Confusionledtothephotoscalenotbeingpresentin

allofthefeaturephotographsandthenortharrownotbeingpresent.Allofthe

featureswererecordedphotographically.

Chapter5

Analysis

5‐1

Introduction

ThischapterwilldiscussthearchaeologicaldatacollectedduringtheJuly

2009andFebruary2010investigationsoftheLVT(A)‐4siteinTanapagLagoon,

Saipan.Findingswillbeexplainedusingacombinationofphotographs,tablesand

siteplans.Abriefexplanationofpossiblesiteformationprocesseswillbepresented

usingprocessanalysis.

Location

ThesiteislocatedinTanapagLagoononthenorthwesternsideofSaipan,

CommonwealthoftheNorthernMarianaIslands(figure5‐1).Thesiteissubmerged

in2‐10ft(.61‐3.05m)ofwaterroughly3,280.84ft(1000m)fromshore.TheLVT

issituatedinasandyareaontheoutsideedgeofalargepatchreef.Thisareaofthe

lagoonishometonumeroustropicalfishandraysaswellasseaturtles,hardand

softcoralsandothermarineflora.Thesiteispresentlybeingcolonizedbysomeof

thesemarinespecies.

Figure5­1:ImageofSaipansurveyareacircledinyellow.(Image:GoogleEarth.Date

accessed10March2010).

5‐2

July2009Findings

InJuly2009archaeologistsfromFlindersUniversityconductedaninitialsite

investigationontheLVT(A)‐4inTanapagLagoon.Theobjectiveofthese

investigationswastolocateandidentifykeyfeaturestobeusedindeterminingthe

exactproductionmodelofAmtrac.KeyLVTfeaturesnotedweretheshapeofthe

grouser,theoveralllengthandbreadthofthesite,thedrivesprocket,suspension,

driveshaft,bowtowingring,windscreenandturret.Aftertheinspection,historical

researchdeterminedthattheAmtracinquestionisanearlyproductionmodel

LandingVehicleTracked(Armored)‐4.

TheearlyproductionLVT(A)‐4sarerecognizablebythesemi‐closed75mm

Howitzerturretwithasingle.50calibermachinegunscarfringontherear(Mesko

1993,30).Also,thetowingringonthebowismountedhorizontallywhilelate

productionmodelshaveaverticaltowingeyethroughwhichalargeshackleis

secured(DepartmentoftheArmy1951,6‐8).Thewindscreenoflaterproduction

modelLVT(A)‐4spossessed2viewportswhereastheearlymodelshadasingle

armoredhatchforthecrewtosecureduringbattleoperations.Alsotheearlymodel

LVT(A)‐4sdidnotcomeequippedwitha.30calibermachinegunportinthebow.

Thisinformationallowedarchaeologiststoidentifyoffieldexpedientarmor

modificationsdoneinresponsetopre‐impactthreatassessments.

5‐3

Figure5­2:ComparativeimageofearlyandlatemodelLVT(A)­4s.(Image:Mesko1993,p.

30).

February2010Investigations

ThepurposeoftheFebruary2010investigationsweretorecordtheLVT(A)‐

4infinerdetailinordertocompleteanaccuratescaledmapofthesite,todetermine

ifmorefieldexpedientmodificationswerepresent,torecordtheextentofsalvage

operationsundertakenandtogatheranyadditionaldatathatmayyieldcluesasto

whythisLVTisinitspresentlocation.Featuresnotedduringthissurveyincluded

anyareasthatappearedtobedamaged(holes),modified(anythingnotinthe

originaldesign)andevidenceofsalvage(evidenceofmissingcomponents,cut

marks).ThesedataarereflectedintheLVTsiteplans(figure5‐4).

5‐4

Figure5­3:PortsideprofileofLVT(A)­4inTanapagLagoon.(Image:Arnold2010).

Figure5­4PlanViewofLVT(A)­4inTanapagLagoon.(Image:Arnold2010).

5‐5

Figure5­5DiagramofLVTfeatures.(Image:Arnold2010).

Feature1

Oneofthemostobviousfeaturesofthesiteistheabsenceofalmostallofthe

armorplatingacrossthedeck,cabin,tracks,andengineroom(figure5‐6).Thetop

andportsideofthearmoreddriver’scabinisalsomissingaswellasmostofthe

starboardsideofthecabin.Afterconductinga360‐degreenon‐disturbancecircle

searchoutto65.62ft(20m)aroundthesitenoneofthearmorplatingoranyother

culturalmaterialwaslocated.

5‐6

Figure5­6:OverviewofLVT(A)­4site.(Photo:courtesyofShipsofExplorationandDiscovery).

Feature2

The75mmturrethassettledintothebelowdeckspaceunderneathit.The

LVT(A)‐4’ssuperstructuressupporttheturretincombinationwithlateralsupport

beams,transversebeamsandareartransversebulkhead,whichacttoelevatethe

turretabovethedriver’scabinoperationalLVT(A)‐4s.Uponfurtherinvestigation,

itwasnotedthatthelateralsuperstructuresupportframeontheportsidehas

shearedoffandsettledinsidethebelowdeckspace(figure5‐7).

5‐7

Figure5­7:Imageshowingcollapsedportlateralsupportoutlinedinyellow.(Photo:courtesyofShipsofExplorationandDiscovery).

Thestarboardsideframeisbentdownwardsinanarchfromthebowtothe

sternandshearedoffwhereitissupposedtoconnecttotheafttransversebulkhead

(figure5‐8).Thedeclinationofthestarboardlateralsupportwasrecordedfromthe

afttransversebulkheadtothepointwerethebowplatingmeetsthesupport(table

1).Itwasdiscoveredthattheverticalsupportsforthesuperstructurearebentina

5‐8

“U”shapeintheforwardsectionandmissingtowardstheaftportion(figure5‐9).It

wasalsofoundthatthetransversesupportbeamsandtransversebulkheadare

collapsedundertheturret(figure5‐10).

Figure5­8:PhotodemonstratingtheStarboardLateralsupportoutlinedinyellowwith2mscale.(Photo:courtesyofShipsofExplorationandDiscovery).

5‐9

Table1:StarboardLateralSupportDeclinationFromtheAftTransverseBulkheadtothePointWheretheBowPlatingmeetstheLateralSupport.

Figure5­9:Viewofbentverticalsupportoutlinedinyellowwith2mscale.(Photo:courtesyofShipsofExplorationandDiscovery).

Baseline Declination 9.51ft (2.9m) 22.44in (57cm) 10.17ft (3.1m) 22.44in (57cm) 10.83ft (3.3m) 20.05in (56cm) 11.48ft (3.5m) 20.05in (56cm) 12.14ft (3.7m) 19.69in (50cm) 12.80ft (3.9m) 18.50in (47cm) 13.50ft (4.1m) 16.93in (43cm) 14.76ft (4.5m) 10.24in (26cm) 15.42ft (4.7m) 6.30in (16cm) 16.10ft (4.9m) 3.54in (9cm) 16.40ft (5m) 1.20in (93cm)

5‐10

.

Figure5­10:Collapsedtransversebulkheadoutlinedinyellowunderturret.(Photo:courtesyofShipsofExplorationandDiscovery).

Feature3

Fourlargeholeswereidentifiedinthelowerportionofthebow(figure5‐

11).Theopenareasappeartocorrespondtothebow’ssuperstructure.Theholes

wereplottedusingtriangulationfromthestillpresentportionsofthebowand

addedtothesiteplan.Theexistingplatingwasgaugedwithcalipersinorderto

determineiftheLVTcrewhadperformedthefieldexpedientmodificationofadding

boilerplatetothehull.Thelowerhullplatingthicknessrangesfrom3/8in(9.52

5‐11

mm)to5/8in(16mm).

Figure5­11:Viewofholesinbow.(Photo:courtesyofShipsofExplorationandDiscovery).

Feature4

Theupperportionofthebowexhibitsaholedirectlyinfrontofthedriver’s

cabin(figure5‐12).Theexistingmetalaroundthisperforationwasgaugedusing

calipers.Thethicknessofthismetalis5/8in(16mm).Theholeisofan

indeterminatenaturebutmaybeevidenceoftheuseofacuttingtorch,indicating

secondarysalvage.

5‐12

Figure5­12:Viewofholeinupperbowarmorforwardofthewindscreen.(Photo:courtesyofShipsofExplorationandDiscovery).

Feature5

Acoaxialmounted.30calibermachinegunportispresentinthewindscreen

ofthedriver’scabin(Figure5‐13).Thisgunportislocatedinfrontoftheradio

operator’sseat.Thecoaxialmountis11in2(27.94cm2.)atitsbaseandtapersto6

in2(15.24cm2)aroundthegunport.Thisisanarmamentfeaturethatwasnot

includedinLVT(A)‐4designuntilaftertheBattleofSaipan.

5‐13

Figure5­13:.30calcoaxialmachinegunportlocatedatradiooperator’sseat.(Photo:courtesyofShipsofExplorationandDiscovery).

Feature6

Otherthanthefrontwindscreen,thecabinstructureisalmostcompletelymissing.

Thefrontwindscreenpossessesa.30cal.coaxialmachinegunmount(figure5‐13)

andanarmoredhatchcoverinfrontofthedriver’sseat(figure5‐14).Thetopofthe

cabinareaismissingjustaftofwherethearmoredcoveringshouldmeetthe

windscreen(figure5‐15).Theinteriorofthecabinhasbeenstrippedofall

nonessentialmachinery,butthedriver’ssidestillpossessesthedriver’sseat,

steeringcontrolsandinstrumentpanelcontainingtheenginegaugesinsitu(figure

5‐16).Therearenootherinstrumentsorelectricalpanelspresent.The

transmissionisinsitualongthecenterlineofthecabin.Thecompassofthevehicle,

whichmountedtothetopofthetransmissionhousingtotherightofthedriver,is

alsomissing.Theradiooperator’sareaisintotaldisarrayandtheradiosand

5‐14

connectingwiresaremissing.The.30cal.machinegunisnotpresent.Hosesfrom

thetransmissionandapileofdebrislaywheretheradiooperator’sseatwasonce

located.Therealsoappearstobedamagetothehullpanelsforwardoftheradio

operator’sstation,whichallowsonetoseeoutofthebowthroughFeature3.

Figure5­14:Concretedarmoredhatchcoverlocatedatdriver’sseat.(Photo:courtesyofShipsofExplorationandDiscovery).

.

5‐15

Figure5­15:Overviewofcabarea.(Photo:courtesyofShipsofExplorationandDiscovery).

Figure5­16:Viewofinstrumentpanelthroughthesteeringcontrols.(Photo:courtesyofShipsofExplorationandDiscovery)

5‐16

Feature7

Largeholesarepresentinthepontoonsonbothsidesofthevehicle(figure5‐

17).Theseholesarelocatedjustaftoftheforwardsteppocketsandpenetrate

throughthepontoontotheinteriorofthecraft(figure5‐18).Theholesare25.59in

(65cm)inheightfromthesedimentleveland13.79in(35cm)attheirwidestpoint.

Themetalplatingofthepontoonsissolidwithlittlesignofcorrosion.

Figure5­17:Overviewofportsidepontoonwithlargehole.(Photo:courtesyofShipsofExplorationandDiscovery).

5‐17

Figure5­18:DetailofPortsideholeinpontoon.(Photo:courtesyofShipsofExplorationandDiscovery).

Feature8

Theturretisbasicallyanemptyshell,ithasbeenstrippedofits75mm

Howitzer,allofthefirecontrolsandallofthemanualandelectricalturrettraversing

controls(figures5‐19,5‐20,5‐21).Whatismostsignificantabouttheremainsis

theadditionof3/4in(19.05cm)armoredplatingaroundthe.50cal.machinegun

scarfring.Thearmoredshieldisarrangedinasemi‐closedoctagonalshapewith

oneopeningoftheshieldaroundthemountforthe.50cal.machinegunatthestern.

Alargeropeningisattheforwardcenterofthescarfring.Itappearsthatthearmor

shieldingdidnotallowforthemachineguntomovefreelyandwouldrelyonthe

movementoftheturrettoengageenemies.Thearmorshieldconsistsoffour

armoredpanels11in(27.94cm)high.Thelengthsofthepanelsvary;ontheport

5‐18

sideonepanelis14.5in(36.83cm)longandtheotheris12in(30.48cm)longand

thestarboardsideoftheshieldconsistsofa14in(35.56cm)longpanelandan11in

(27.94cm)longpanel.Anotherpointofinterestontheturretisanapparent

corrodedmachinegunmountonitsportside(figure5‐22).

Figure5­19:Detailofturrettraversinggears.(Image:DepartmentoftheArmy).

Figure5­20:Modifiedarmoredshieldoutlinedinyellowandpossiblemachinegunmountoutlinedinred.(Photo:courtesyofShipsofExplorationandDiscovery).

5‐19

Figure5­21:Detailofmodifiedarmoredshielding.(Photo:courtesyofShipsofExplorationandDiscovery).

Figure5­22:Detailofpossiblemachinegunmount.(Photo:courtesy

ofShipsofExplorationandDiscovery).

5‐20

Feature9

Theenginecompartmentofthevehicleisvoidofalmostallmachineryother

thantheradialengine(figure5‐24).Hoses,pumps,filters,vents,generators,air

cleanersandoilcoolersareallmissing(figure5‐23).Additionally,thereisagreat

dealofsedimentlocatedinthecompartment;othercomponentsmaybelocated

beneaththissedimentlayer.Theengineismostlycoveredwithsediment,andonly

threeofitscylindersareexposed.Thecylinderheadsandvalvecovershavebeen

removedandarefilledwithsediment.Twoexhaustmufflersareinsitualongthe

transomhowevertheirflexiblehosesaremissing.Itisreasonabletoassumethe

enginecomponentswereeithersalvagedordeliberatelydismantledtoprevent

furtherusage.

Figure5­23:DetailofLVT(A)­4engineasitappearsinstalled.(Image:DepartmentoftheArmy).

5‐21

Feature10

ThesplashguardsofthisLVTaremissingandthefenderbracketaround

wherethesplashguardsshouldbelocatedappearstohavebeencut(figure5‐26).

Thebracketshouldbeatriangularshapeandmounttothetransomandaroundthe

backofthesplashguardstotheoutsideofthetrackcover(figure5‐27).

Figure5­25:Detailofsplashguardsandfenderassembly.(Image:DepartmentoftheArmy).

Figure5­24:Detailofengineinpresentstate.(Photo:courtesyofShipsofExplorationandDiscovery).

5‐22

.

Figure5­26:Damagedfenderandmissingsplashguardoutlinedinyellow.(Photo:courtesyofShipsofExplorationandDiscovery).

SiteFormation

HistoricalresearchrevealsthatLVTswereusedinthisareaduringtwo

separatefightingengagements.ThefirstmentionofLVTuseinthisareawasduring

thelastbanzaichargeoftheBattleofSaipanon7July1944.DuringthisbattleLVTs

usedthewatersofTanapagLagoonasanavenueofapproachandexit.Thisavenue

5‐23

allowedthemachinesaccesstothecoreareaofthebattleinordertodeliver

suppliesandevacuatecasualties(Bartholomees1948,pp.10‐13).Thesecond

mentionofLVTsoperatinginthisspecificstudyareaison13July1944whenU.S.

MarinesconductedasmallscaleamphibiousassaultonwhatisnowManagaha

IslandinTanapagLagoon.Sourcesstate5LVT(A)‐4sescorted25LVTstotheisland

(Bailey1976,p.180:Rottman2004,p.69).LVToperationsinthisareawere

undoubtedlynotlimitedtothesetwoactionshowevernootherspecificmentionof

LVTsinthisstudyareahavebeenlocatedatthistime.Nohistoricsourceshave

beenlocatedthatmentionthecatastrophiclossordisposalofanyLVTsinthis

portionofthelagoon.

Conclusion

Thischapterhasestablishedthearchaeologicalfindingsofthisinvestigation.

Througharchaeologicalrecordingandhistoricalresearchithasbeendetermined

thatthisAmtracisanearlyproductionmodelLVT(A)‐4basedontheturretdesign,

windscreenandtowingeye.HistoricalsourceshaveproducedevidencethatLVT

crewsdidroutinelymodifytheirvehiclesbeforecombativeactionsanditappears

thatthearchaeologicalevidencesupportsthisactivity.Historicresearchhasalso

linkedLVTsactivitiestothisstudyareahoweveritremainstobedeterminedifthis

LVTwasoneofthoseinvolvedinthetwomissionswithinthisarea.

Thenextchapterwilldiscusspossibleexplanationsforthemodifications

basedontherequiredtasksoftheLVT(A)‐4crews.Processanalysiswillillustrate

5‐24

theperceivednecessityofbattlemodificationsandpossiblereasonsforthesite’s

formation.

Chapter6

Discussion

6‐1

Introduction

Thepurposeofthischapteristodiscussfurtherthearchaeologicalfeatures

describedpreviouslyandhowprocessanalysisisusedtoexaminethenaturaland

culturalfactorscontributingtothesite’sformation.Keyprocessessuchaspre‐

impactthreatphaseandsalvageoperationswillbeusedtoexplaintheoccurrenceof

specificarchaeologicalfeaturesandwillbeexaminedandcontextualizedthrough

historicaldocumentation.

Pre­ImpactThreats,StrategiesandAssessmentsAsIdentifiedintheHistoricRecord

Inordertoclearlydemonstratetheneedforanduseofamphibiouslanding

craftintheBattleofSaipan,itisnecessarytofirstidentifythepre‐impactthreats,

strategiesandassessmentsoftheU.S.forces.TheU.S.invadedSaipanfromthe

westernsideoftheisland(MinistryofDefense1995,p.3)andindoingso

positioneditselftointerceptJapanesecounterattacksandresupplyefforts.This

decisionwasbasedonintelligencereportsthatgaveagoodindicationthatthe

JapanesefleetwasnearthePhilippinestotheWest(MinistryofDefense1995,p.

125).Additionally,theU.S.learnedthroughaero‐reconnaissancethatSaipan’s

westernbeacheswerenotasheavilyfortifiedastherestoftheisland(Goldberg

2007,p.22).Earlierairandnavalbombardmentseliminatedthethreatfromkey

areasonthewesternsideofSaipan,suchasaircraftstandingbyonairstripsand

largecaliberweaponslocatedonManagahaIsland.However,thebeacheschosen

fortheinvasionpossessedafringingreefroughly1500metersoffshoreofthe

chosenlandingsites.Thisreefwasfartooshallowfortraditionallandingboatsto

6‐2

crossandwouldhavelefttheinvadingtroopscompletelyexposedwhilewalking

towardthebeachunderconcentratedenemyfire.

Theanswertotheproblemofgettingthetroopstoshorewithoutcompletely

exposingthemtotheenemywastheLandingVehicleTracked(LVT).Thispieceof

technologyhadbeentriedandtestedfromtheopeningstagesofWWIIinthePacific

beginningwiththeinvasionoftheSolomonIslandsandproveditselftobeavital

pieceofequipmentinthecampaignsleadinguptoSaipan’sinvasion(Bailey1976,

pp.53‐211).Nowinitsfourthgenerationofproduction,theLVTwouldproveits

worthonceagain.

Thefringingreefandlagoonwerenottheonlyfeaturesoftheterrain.The

westernbeachescontainedJapanesefortificationsintheformofreinforcedconcrete

bunkerscontainingartilleryandmachinegunsanddensevegetationfurtherinland.

Additionally,rangemarkerswerelocatedthroughoutthelagoontoaidJapanese

artilleryandmortarcrewstorapidlyandeffectivelyfireonthearrivingU.S.forces

(Adams1950,pp.10‐12,Goldberg2007,p.55).Thesefactorsobviouslyinfluenced

thedecisiontoculturallymodifyLVTsbymeansoffieldexpedientmodifications.

OvercomingThreatsandCreatingStrategiesthroughTechnologyandModification

Theshallowfringingreefdemandedtheneedforamphibiousvehicles.The

LandingVehicleTracked(Armored)‐4(LVT[A]‐4)wasdesignedspecificallyto

destroyJapanesereinforcedbunkersinresponsetothepre‐impactthreatphaseof

planningtheoperation(Mesko1993,p.27).BecauseU.S.airandnaval

bombardmentceasedoncethelandingvehiclesnearedthebeach,theLVT(A)‐4s

6‐3

providedtheonlyclose‐in,largecaliberweaponssupportforthetroopsarriving

behindthem(Barker2004,p.4).Theseamphibioustanksledthewayinfrontofthe

wavesoflandingforcescomingashore.

Becausethesevehicleshadthejobofbeingthefirstinthelineofenemyfire,

itisnowonderthatthecrewsoperatingthemchosetomodifytheirvehiclesfor

betterprotection.CrewslearnedfrompreviousbattlesinthePacifictheaterthat

LVTswerelightlyarmored.However,themanufacturernevercorrectedthis

weaknessduetobuoyancyrequirementsatseaandspeedrequirementsonland.It

isnotedhistoricallythattheLVTcrewsregularlyaddedsheetsofsteelboilerplateto

thebowsoftheircraftbecausethearmorwassothincoralwouldregularly

punctureitwhilecrossingshallowreefs(Barker2004,pp.253‐254,Mesko2004,pp.

27‐28).Alsodocumentedisthefactthatthearmorwasincapableofpreventing

smallcaliberroundsfrompenetratingtotheinteriorofthevehicle(Bailey1976,p.

168).Thisfactisacknowledgedbytheadoptionofapolicytocarrywoodenplugs

forthepurposeofshoringanyholeswhilethevesselwasunderway(Bailey1976,p.

168).Theadditionofsandbagsacrossthedeckalsoaddedalayerofextra

protectionforthemeninside(Barker2004,pp.253‐254).

Modifyingthebowarmorbyaddingboilerplate(Feature3)andsandbags

loweredthevehiclesprofileinthewater,whichwouldcausetheLVTstotakeon

waterinroughseas.Onlandthesemodificationscausedareductioninspeed,which

madethealreadyslowmovingvehicleaneasiertargetfortheenemy.Giventhe

tradeoffofspeedandreducedfreeboardforaddedprotection,thesemodifications

indicatethatthecrewsweremoreconcernedwithprotectingthemselvesfrom

6‐4

enemyfirethenmaneuverability.Thelowersilhouetteinthewatercausedbythe

additionofweightfromtheaddedboilerplatemeantlesstargetareatotheenemy.

LVT(A)swereneverintendedtoreplacetraditionaltanks,thereforethereduction

inspeedonlandmayhaveseemedareasonableexchange.

TheoriginaldesignoftheLVT(A)‐4calledforasemi‐closed75mmturret

withasingle.50cal.machinegunmountonthestern(figure6‐1).Ithasalsobeen

notedthatcrewsaddedimprovisedarmorshields(Feature8)aroundthe.50caliber

machinegunmountbuiltintotheturret.Thisresponsetopre‐impactthreatanalysis

addressedthefactthatthemachinegunnerwasallbutcompletelyexposedto

enemygunfire(Mesko1993,p.27).Thereforethisshieldingisadefiniteattemptat

self‐preservation.Theadditionofanarmorshieldaroundthismachinegunmount

seemsappropriateconsideringthefactthisvehiclewasintendedtoleadanassault

onawellfortifiedbeach(Barker2004,pp.253‐254).Theoperatorswereprolonging

thelifeofthecrewandasaresultprolongingthelifeofthevesselbyweldingsteel

platesaroundthe.50cal.gunmount.

AnotherperceivedproblemwiththeoriginaldesignoftheLVT(A)‐4was

thattherewasnomachineguninthebowofthecraft(Mesko1993,p.27).Abow

machinegunaddedtothemaximumfirepowerofthevehicleontargetsinthepath

oftheinvasionforce.Byaddinga.30calibercoaxialmachinegunporttotheareain

frontoftheradiooperator’sseat,thecreweffectivelyincreasedtheirabilitytobring

enemytargetsunderfirethereforedecreasingthevulnerabilityoftheLVT(Mesko

1993,p.27).Theadditionofacoaxial‐mounted.30cal.machinegun(Feature5)

allowedtheradiooperatortheabilitytodefendthevehiclefromanenemyfrontal

6‐5

attack.Thepositionofthisweaponalsoenabledtheradiooperatortoadminister

suppressivefirewhilestormingagivenbeach.Theadditionofacoaxial‐mounted

.30cal.machineguntothebowoftheLVT(A)‐4appearedonthelaterproduction

modelsperhapsasadirectresultofthemodificationsmadebyLVTcrewsinSaipan.

Increasingthefirepowerofthevehicleaidedinincreasingitslifespanbylessening

theenemy’sopportunitytoshootatit.

TheU.S.militaryalsoestablishedguidelinesonwhattodointheeventan

LVTwasknockedoutofbattle.TheArmy’stechnicalmanualforLVT(A)‐4soutlines

theproperstepsfortheevacuationofequipmentusablebytheenemyand

destructionofthevehicletopreventenemyuse(DepartmentoftheArmy1951,pp.

565‐569).Theprocessesofprimarysalvageareoutlinedinthismanualby

indicatingwhattypeofequipmentshouldbeevacuatedordestroyedandthe

processesofdiscardandabandonmentaredescribedbyvariousmeans.

Figure6­1:ComparativeimageofearlyandlateproductionLVT(A)­4.(Image:Mesko1993p.

30).

6‐6

ArchaeologicalEvidenceofFieldExpedientArmorModificationsandSalvageEfforts

TheLVT(A)‐4locatedinTanapagLagoondemonstratescultural

modificationsmadeatthecrewlevel.Itisreasonabletoassumethatthecrews

operatingthesemachineswerethefirsttonoticedesignflawsandsetabout

modifyingtheLVTsinordertocompensateforthelackofarmorandarmament

priortotheamphibiousassaultonSaipaninresponsetothreatphaseevaluations.

Thesefeaturesundoubtedlyinfluencedonthedesignoflaterproductionmodelsof

LVT(A)‐4snicknamedthe“MarianasModel”.FlawsintheoriginalLVT(A)‐4’s

designledtotheincorporationofnewfeaturestothevehicle.

Figure6­2:LVT(A)­4siteinTanapagLagoondiagramoffeatures.(Image:Arnold2010).

6‐7

Armorplatingmissingfromthesite(Feature1)maybearesultofsalvage

priortoorafterdisposalofthisLVT.Itisunlikelythearmorplateswouldhave

deterioratedundernaturalconditionsorfloatedaway.The20m‐circlesearchdid

notrevealanyculturalmaterialrelatedtothisoranyotherwrecksignifyingthisisa

continuoussiteduetothelackofadebrisfield.IftheLVTinquestionwasthe

victimofenemyactionwhileunderwayinthelagoon,itisreasonabletoassumethat

therewouldbedebrisassociatedwithacatastrophiceventscatteredaroundthe

site.

Thelateralsupports,stanchionsandtransversebulkhead(Feature2)

demonstratesignsofseverestress.Thestarboardstanchionshavebentcausingthe

starboardlateralsupporttoarchdownwardstowardstheturret,whiletheport

lateralsupportisshearedoffcompletely.Itisunclearifthisisevidenceofbattle

damage,intentionaldestructionduringthedisposalprocessoriftheturret

collapseduponitselfduetodeterioration.Theseverityofdamagetothe

superstructureisobservablebothforeandaftoftheturret.

Thetransversebulkheadandassociatedsupportbeamswerelocated

collapsedundertheturret.Thusitispossiblethatovertimetheweightoftheturret

anddegradationofthestructuralsupportscausedthecollapse.Anotherpossible

reasonforthecollapseisoutlinedintheArmy’stechnicalmanualforLVT(A)‐4s.

Thismanualdescribesthatduringtheprocessofdisposaloneshouldplacea“3‐

poundchargeagainsttherightfueltankbetweentheengineandbulkhead”

(DepartmentoftheArmy1951,p.568).Thisdisposalmethodmayhavecausedthe

6‐8

bulkheadtocollapseundertheturretandresultinthelateralsupportsgivingway

undertheweightoftheturret.

Theactualgaugedthicknessofthelowerbowplating(Feature3)is5/8in

(15.88mm).Incontrast,thethicknessofthelowerbowplatingoftheLVT(A)‐4asit

cameofftheassemblylinewas1/4in.(6.35mm)(DepartmentoftheArmy1951,p.

15).Theholediscoveredintheupperbow(Feature4)areawasgaugedtobe5/8in

(15.88mm).Themanufacture’sspecificationsforthearmorplatingontheupper

portionofthebowwas1/4in(6.35mm)(DepartmentoftheArmy1951,p.15).

Thesegaugedthicknessesofthearmoredplatesonthelowerportionofthebow

indicateanaddedlayerofprotectionthatcanbecategorizedaspre‐impact

modificationduetoaperceivedthreat.Iftheoriginalspecificationof1/4in

(6.35mm)armorplatingisaddedtothehistoricallydocumentedpracticeofadding

3/8in(9.53mm)boilerplatetothelowerportionofthebow,thesumofthe

combinedthicknessequals5/8in(15.88mm).Itisreasonabletoassumethatthe

rangeofmeasurementsmaybeduetothedeteriorationand/orbattledamagetothe

vessel.Nevertheless,basedonthemanufacturers’specifications,thebowofthis

vesselappearstohavebeenmodifiedbyaddingextrasteelhowever.Thereasonfor

theholesbeingpresentisunclear.Theholeintheupperbowisanirregularshape.

Somepossibleexplanationsaredamageduetoexplosionoraveryquickcuttingjob

duringsalvageoperationstoaccessgearinsidethecabin.

Theaboveandportsideofthedriverscabin(Feature6)iscompletely

missing.Itcanbeassumedthatadirecthitbyenemyordnancewouldcausesever

damagetoavehicleofthisconstruction,butthearchaeologicalsignatureofthissite

6‐9

suggestsintensesalvageefforts.Ifthiswerethesiteofacatastrophiclossitwould

bereasonabletoassumethatsomeoftheheaviervehiclefragmentswouldbe

locatedonoraroundthesiteasindicatedbyMuckelroy’sprocessmodel(Muckelroy

1978,p.158).Additionally,thecharacteristicsofmetaldamagedbyordinance

includedjagged,roughandinconsistentedges.TheLVTdisplaysnoneofthese

characteristicsinthisarea.

Themissingareasofthecabmayhavebeencutawayforeasyaccessinorder

tosalvagemachinery.Thelackofsuperstructureandupperdeckplatesmay

indicateremovalforsalvagepurposespriortodisposal.Thelackofequipment

presentinthecabmayalsoindicateintentionaldisposalaftersalvage.Theremoval

ofallusableitemsfromavehiclebeingdisposedofisoutlinedintheArmy’s

technicalmanualforLVT(A)‐4s(DepartmentoftheArmy1951,pp.565‐569).The

manualalsostatesthata“2‐poundchargebeplacedontheleftsideofthe

transmissionasfarforwardaspossible”duringdisposal(DepartmentoftheArmy

1951,p.568).Beingthatthismanualdatesto1951,itmaybepossiblethatthese

guidelineswerenotinplaceduringtheBattleofSaipan.Iftrue,thechargemayhave

beenplacedontherightsideofthetransmissionorahandgrenademayhavebeen

tossedintothecabandlandedintheradiooperator’sseat.Thismayaccountforthe

holesinthestarboardlowerbowandthegeneraldisarrayoftheradiooperators’

station.Interestingly,thefactthatthesteeringcontrolsandinstrumentgaugesare

insitumaybeindicationofdisposingthevehiclewhileunderitsownpropulsion.

Iftheholesinthepontoons(Feature7)werelocatedatthesteppocketsthey

couldbearguedtohaveoccurredduetodegradation.Howeverthesteppocketsare

6‐10

intactonbothsidesofthevehiclewithminimalsignsofdeterioration.Becausethe

holesarenotlocatedinwhatcouldbeconsideredaweakpointinthepontoonand

thesteppocketsarepresent,itisreasonabletoconcludethattheholesarea

deliberateindicationofeitherdiscardorbattledamage.Theseholesmayhavebeen

causedbyplacingexplosivesinsidethepontoonorpossiblybylargecaliber

weapons.Bothofthesemethodsofthevehicledisposalprocessareoutlinedinthe

Army’sTechnicalManualforLVT(A)‐4s.Themanualindicatesthatthediscardof

anLVTbymeansofdemolitionrequiresthata2‐poundchargeshouldbeplacedat

thecenterofthetracksandthatthechargesshouldbeconnectedbydetonatingcord

(DepartmentoftheArmy1951,p.568).Discardbygunfireisoutlinedbyfiringall

availableweaponsattheenginecompartment,suspensionandarmamentinthe

orderspecified.(DepartmentoftheArmy1952,p.569).Againthearchaeological

signatureofthesitepointstodeliberatediscard.

Theturret(Feature8)hasbeenstrippedofthehowitzer,sightingoptics,

traversingmechanicsandfiringcontrols.Theevacuationoftheseitemsduringthe

disposalprocessisexplicitlystatedintheArmy’sTechnicalManualforLVT(A)‐4s.

“Allitemsofsightingandfirecontrolequipment,includingsuchitemsasperiscopes,

telescopes,andbinoculars,arecostly,difficulttoreplace,yetrelativelylight;hence,

wheneverpracticable,theyshouldbeconservedandevacuatedratherthan

destroyed.Intheeventofsubsequentabandonment,theequipmentwillbe

completelydestroyed,allopticalelementsandmountingssmashedandfiringtables,

trajectorychartsandinflammableitemsburned”(DepartmentoftheArmy1951,pp.

565‐569).

6‐11

ThepossiblemachinegunmountontheportsideoftheLVT’sturretmay

havebeenaddedinordertocompensateforthelackofmobilityofthe.50cal.

machinegunduetotheadditionofthefieldexpedientmodifiedarmorshield(figure

6‐2).LateproductionLVT(A)‐4modelsdidawaywiththe.50cal.machinegun

mountedontherearoftheturretandreplacedthemwithtwo.30calmachineguns

mountedonbothsidesofthe75mmturret.Ifthispossiblemountwereusedto

supportamachinegunitwouldbeathreatphaseculturalmodificationandisa

directlinkbetweenexpedientarmormodificationsandthedevelopmentoflater

productionmodels.

Figure6­2:EarlymodelLVT(A)­4swithsquaremodifiedarmoraround.50machinegun

turretandwhatappearstobea.50machinegunmountedtotheportsideoftheturret.

(Photo:courtesyofKathleenDale).

6‐12

Thelackofequipmentpresentintheenginecompartment(Feature9)may

beduetodeteriorationprocessesovertime.Itispossiblethattherubberengine

componentshavedecomposed,howeverthevalvecoversandcylinderheadswould

havetobemanuallyremoved.Itisunknowniftheirremovaloccurredpriortoor

afterthisvehiclewassunk.ThelackofmachinerysuggeststhatthisLVT’sengine

compartmentwasstrippedofallusableparts.TheArmy’stechnicalmanualforLVT

(A)‐4sdoesnotspecificallystatehowtodisableanengineduringdisposal.

However,itdoesstatethataboatbebroughtalongtothesiteofdiscardtopickup

thecrewiftheLVTisunderitsownpower.ifthisvehiclewasdisposedofunderits

ownpowertheenginewouldhavetobeintactinordertooperate.

Themissingsplashguards(Feature10)mayofferfurtherevidenceof

salvagingeveryusablepartfromtheLVT.Thefenderassemblyappearstohave

beencutinordertoeasilyremovethesplashguardsonboththeportandstarboard

sides.

Conclusion

ThedesignoftheLVT(A)‐4iswhatGibbs(2006)describesthecreationand

modificationofanewvehicleinanswertopre‐impactknowledgegathering.This

LVT(A)‐4showssignsofpre‐impactthreatmodificationduetotheperceivedrisks

associatedwithitsmissionobjectives.Theextentofprocessesrelatedtophysical

deteriorationisnotknownatthistime.Ifanyorganicorrubbermaterialswere

presentatthetimeofsinkingtheywouldhavemostlikelydecomposed.Mostofthe

existingsteelisstillsolidandshowslittlesignofdegradation.

6‐13

Thelackofmaterialsinoraroundthesitesuggestssalvageprocesses,

howeveritisunknowntowhatextentprimaryandsecondarysalvageoccurred

(figure6‐6).Theevacuationofallvehicleelementsusablebytheenemypriorto

disposalisoutlinedintheArmy’stechnicalmanualforLVTs(Departmentofthe

Army1951,pp.565‐569).TheArmy’stechnicalmanualforLVT(A)‐4sproper

processfordisposalappearstohavebeenfollowedinmostcases.Thereisevidence

ofevacuationofequipment(Features1,4,6,8,9,10),possibledamagebygunfire

(Features3,7)and/orpossibledamagebyexplosives(Features1,2,3,7).One

discrepancyisthatthemanualcallsforacrafttobedumpedatadepthnolessthan

50ft.(15.24m).Thedepthatwhichthissiteislocatedallowseasyaccessfor

anyonewithashallowdraftvesseltoaccessthesite.Thismightbeexplainedbythe

distancefromshorehavingbeendeemedfarenoughtopreventrecovery,ortheLVT

mayhavebeendumpedaftertheislandwassecured.Analternativeisthevessel

mayhavebeenunderitsownpowerduringthedisposalprocess,accidentally

floodedenrouteandwassimplyabandoned.ThemethodofdisposingofanLVTby

sinkingwhileunderitsownpowerisoutlinedintheArmy’sTechnicalManualfor

LVT(A)‐4swithanoteofcaution:“Ifadrainplugmustberemovedfrom

underneaththevehicle,thismethodofdestructioncanbeundertakenonlyifthe

distancethevehiclehastotraveltoreachthenecessarydepthisnottoogreat”

(DepartmentoftheArmy1951,p.567).

HistoricsourcesdonotmentionthedestructionordisposalofLVTsinor

aroundTanapagLagoon,whichlimitstheabilitytotiethisparticularLVT(A)‐4toa

specificaction.Unfortunatelynoserialnumbersorotherformsofidentification

6‐14

markerswerelocatedonthisvessel,whichhindertheabilitytotiethevehicletoa

specificU.S.militaryunitforfurtherresearch.Accordingtolocaldivers,several

LVTsarelocatednorthwherethereefmeetstheislandonthewestcoast.These

LVTsarerestataconsiderabledepthofwater(roughly98‐164ft[30‐50m])and

mayhavebeenpushedoverthereefedgeaspartofadisposalproject.Future

investigationsofdisposedLVTsinSaipanshouldincludetheinvestigationofthese

LVTstocomparethemwiththisLVTsite.

Amodelbasedonpreviousmodelsofsunkenshipwreckshasbeencreatedas

apartofthisresearchinordertodemonstratesomeofthepossiblescenarios

concerningthesiteformationprocessoftheLVT(A)‐4inTanapagLagoon.

Figure6­5:FlowchartshowingpossiblescenariosconcerningtheLVT(A)­4inTanapagLagoon.(Image:Arnold2010).

6‐15

Figure6­6:Viewofsitefromstarboardside.(Photo:courtesyofShipsofExplorationandDiscovery).

Chapter7

Conclusion

7‐1

Introduction

Thischapterwilldiscusstheimplicationsofthisstudyasitrelatestothe

originalaimsandresearchquestionsstatedinChapter1.Themainandsubsidiary

questionswillbeansweredusingthehistoricalandarchaeologicalevidence

uncoveredinthisresearch.Additionallythefutureresearchpotentialofthisand

otherLVTswillbediscussed.

HowWereLVT(A)­4sUsedinSaipan?

HistoricalresearchshowsthatLVT(A)‐4sprecededthelandingforce,

effectivelyplacingthemfirstinharmsway.LVT(A)‐4sweretheonlyartillery

supporttheinvadingtroopshadoncetheynearedtheshorelineuntiltraditional

tankscouldbedeployedinlaterlandingwaves.Onceashoretheyactedasmobile

artilleryandhelpedcapturestrategictargetssuchasthetownofGarapan.LVTs

actedinavarietyofrolessuchascommandposts,logisticalvehiclesandrescue

vehicles.Theywereabletoapproachandevacuatebattlefieldsinwaysthatwere

unavailabletotraditionalvehicles.ThiscapabilitygreatlyenhancedtheU.S.ability

toattackJapanesedefendersandtodefendthemselvesfromcounterattacks.

PerceivedweaknessesintheoriginaldesignspecificationsledtheLVTcrews

tomodifytheirvehicles.Duringthepre‐impactthreatphase,thesemodifications

weredeemednecessaryinordertoprolongthelivesofthemachinesandthecrews

whooperatedthem.ThemodificationsofLVTshavebeendocumentedhistorically

andnowarchaeologicallygivinginsightintohowLVTcrewsviewedtheirmachines

7‐2

asvehiclesofwar.TheperceivedweaknessesinpreviousLVTmodelsdirectly

influencedtheirpredecessorsonthebattlefield.

Atthetime,theBattleofSaipansawthelargestuseofLVTsincombat.Both

thetroopcarryingLVT‐4andtheAmtankLVT(A)‐4wereintroducedforthisbattle

attestingtotheattentiongiventopre‐impactconsiderationsbythoseplanningthe

operation.ThearchaeologicalevidencepresentedbytheLVT(A)‐4inTanapag

Lagoonindicatesthatitscrewnotonlyconsideredpre‐impactthreats,butalso

modifiedtheirvesselaccordingly.

HowandWhydidtheLVTCrewsModifiedtheirVehiclesfortheBattleofSaipan?

Inresponsetoperceivedthreatsduringthepre‐impactphase,cultural

actionsintheformoffieldexpedientbattlemodificationswerecarriedout.Historic

recordshaveshownthatthecoralheadsoffringingreefswerecapableof

penetratingtheunmodifiedbowarmorofLVTs.Likewisesmallcaliberroundswere

capableofpenetratingLVTarmor.Thisknowledge,combinedwiththeintelligence

gatheredconcerningtheInvasionofSaipan,wouldhavebeenconsideredduring

pre‐impactthreatassessments.TheseconsiderationsinfluencedtheLVTcrews

leadingtheamphibiousassaultstomodifytheirmachinesinreactiontothese

threatswithextrasteelplatestobetterpreserveandprotecttheircraftand

themselveswhileattemptingtoaccomplishtheirmissions.Evenwiththeadded

protectionofsteelplating,itwasnecessaryfortheLVTcrewstocarrywoodenplugs

inordertopatchholeswhileunderwayatsea.

7‐3

Theexposed.50calmachinegunnerwouldcertainlywantmoreprotection

whileassaultingtheenemy.Likewise,theadditionofextraweaponrywouldbe

welcomeonthebattlefield.Thestudyoffieldexpedientarmormodifications

suggestsself‐preservationtobethecommonmotivebehindthecrews’actions.This

attitudeisclearlyreflectedinthearchaeologicalremainsoftheTanapagLagoon

LVT(A)‐4.

HowAreTheseModificationsReflectedintheArchaeologicalRecord?

Pre‐impactfieldexpedientarmormodificationsintheformofadded

weaponryandarmorshieldsareeasilyobservableontheLVT(A)‐4.Archaeological

researchhasidentifiedtheadditionone.30cal.coaxialmachineguninthebowof

thisLVT(A)‐4.Anotherprobablemachinegunmountisattachedtotheportsideof

theturret,whichwouldhaveaddedconsiderablefirepowerandprotectionforthe

vessel.PerhapsthemostobviousmodificationtothisLVT(A)‐4istheadditionofan

armorshieldaroundthe.50cal.machinegunontherearoftheturret.

Fieldexpedientarmormodificationssuchasaddingsteelplatingtothebow

ofthevesselsinordertoincreasetheprotectivearmorhavebeendiscussed

historically.Thepracticeofaddingboilerplatetothebowofthecrafthasbeen

archaeologicallydocumentedbygaugingtheexistingbowplatesonboththeupper

andlowerbowofthisLVT(A)‐4andcomparingthistohistoricsourcesdetailingthe

manufacturer’sdesignspecifications.

7‐4

WhatistheSignificanceofLVTsDuringtheInvasionofSaipanasitRelatestothe

DevelopmentoftheLVTasaMachineofWar?

Lessonslearnedinpreviousbattlesestablishedthatthe37mmturretofthe

LVT(A)‐1wasineffectiveonJapanesefortifications.TheLVT(A)‐4wasapre‐

impactthreatresponseintroducedspecificallyfortheBattleofSaipanandwas

designedwitha75mmHowitzerforthepurposeofdestroyingJapaneseweapon

emplacementsandfortifications.Thesevesselsmarkachangeintimeconcerning

theequipmentandsuppliesofU.S.forcesduringWWII.Historicalresearchhas

shownLVTstobetheonlyamphibiousvehiclescapableofdeliveringlargeamounts

oftroopstoshoresshelteredbyshallowfringingreefs.Likewise,thesevehicles

providedtheonlyconcealmenttotheinvadingforces.LVT(A)sweretheonly

artillerysupporttheinvadingforcesreceivedoncethelandingpartiesnearedthe

shorelinebeforetraditionaltankscouldbedeployedtothebeaches.

ThestudyoffieldexpedientarmormodificationsmadetoLVTsusedinthe

BattleofSaipanastheyrelatetotheprocessofpre‐impactthreatassessments

presentsthebasisforunderstandingthedegreeofmodificationstandardization

betweenunitsandservices,byboththeU.S.andothernations.Thesemodifications

havepresentedinsightintothemindsetofthoseoperatingLVTs.These

modificationshavealsoillustratedadirectinfluenceontheseriationoflater

productionLVTmodels.

7‐5

SiteFormationPossibilities

FollowingtheprocessmodelestablishedbyMuckelroy(1978),the

archaeologicalsignatureofthissitedemonstratesthatithasbeenheavilysalvaged.

Therearenoheavypiecesofmetalinoraroundthesiteandnoammunitionofany

kind,spentorunspentwaslocated.Thesiteappearstohavebeensubjectedto

primarysalvageduetothelackofmachinery,electronicdevicesandweaponsas

outlinedintheArmy’sTechnicalManualforLVTs.Itisunclearhowmuch,orifany

secondarysalvagehasoccurred.Todatenohistoricrecordshavebeenlocated,

whichtiethissitetoanyactionsofuse,disposalorloss.Itisreasonabletoassume

thatthisLVTwasdamagedinbattlehowever;itisnotknownifthisdamage

occurredonshoreorinthewateratitspresentlocation.Thelackofdebrisfield

suggeststhatthisLVT(A)‐4wasnotdamagedatitscurrentlocation,butdiscarded

aftersalvageeffortsoccurredelsewhere.

Itappearsthatthe1951Armytechnicalmanualdescribingtheproper

disposalofLVTswasfollowed(althoughdatedlater,therewaslikelyanearlier

version)(DepartmentoftheArmy1951,pp.565‐569).Allsensitiveequipmentand

weaponswereremovedandthevesselwassunk.TheinabilitytoacquireanLVT

technicalmanualpreceding1951makesitunclearifthedisposalmethodswereset

forthpriortotheinvasionofSaipan.Thedeliberatedisposalofthiscraftcouldhave

providedthebasisfortheguidelinessetforthinthe1951Armymanual.

7‐6

FutureResearchPotential

TheLVTisaspecializedmachinethathasbeenlargelyignoredby

researchers.FutureresearchmayshedlightontheextentofLVTmodification

occurrenceinWWIIbattlefieldsacrossthePacificandEuropeandthe

standardizationofthesemodificationsbetweenindividualunitsofboththeU.S.and

othernations.Thisresearchhasthepotentialtodocumentthecrewlevelthreat

responsesthatinfluencedtheevolutionoftheLandingVehicleTrackedfromthe

humblebeginningsofahumanitarianrescuevehicletoamphibiousmilitarysupply

crafttoamphibiousassaultvehicleandeventoitsmoderncounterparts.

Moreresearchonthesemachinesmayalsoleadtoadiscernablepattern

concerningcatastrophiclossascomparedtointentionaldisposal.Byrecognizing

thesignaturesofbothtypesofsitesamorecompletemodelcanbeproducedtoaid

ininterpretingfutureLVTsites.

LVTswereusedduringWWIIinthePacificonmanydifferentislands.The

LVTalsoreceivedlimiteduseinEurope.ThesemachineswereleasedtoAllied

countriesandmayhavereceivedexpedientmodificationsbythesenations’soldiers.

AstudyofhoweachmodelofLVTwasmodifiedforuseduringwartimemay

potentiallyyieldmoreinformationabouthowthecraftbecamesuchadiversewar

machineandofferinsightastohowtheseriationofthevehiclewasinfluencedby

thoseusingthevessel.Further,moreinformationregardingtheimportanceofLVTs

duringamphibiousinvasionscanbegainedbystudyingtheterraininwhichthey

wereusedtoinvestigatelocaluseandresponsetoconditions.

7‐7

Conclusion

TheLVT(A)‐4siteinTanapagLagoonissignificantforitsroleintheU.S.

victoryoftheBattleofSaipanduringWWII.LVTscontributedtosavinglivesduring

invasionoperationsbyferryingtroopstoshoreunderheavyfireandevacuatingthe

woundedfromareasofintensefightingtoshipswaitingatsea.Theunique

capabilitiesofthesevesselsallowedalliedforcestheabilitytoutilizenewstrategic

methodsinwarfare.

ThefieldexpedientarmormodificationsofthisparticularLVTaresignificant

becausetheyreflectthemindsetofindividualsrespondingtopre‐impactthreat

processesduringWWII.Thedifficultyofthemissionsandthedesignlimitationsthe

crewsofthesevehicleswereconfrontedwitharereflectedinthearchaeological

record.Extensivefieldexpedientarmormodificationsforthesakeofself‐

preservationweredeemednecessarybyLVTcrewsinordertoaccomplishthemany

taskstheyfaced.

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