▁Nelson ▁in ▁command . ▁ ▁Service ▁history ▁ ▁World ▁War ▁II ▁ ▁Late ▁in ▁December ▁ 1 9 4 2 , ▁Pet o ▁de comm ission ed , ▁was ▁loaded ▁on ▁a ▁bar ge , ▁and ▁depart ed ▁Man it ow oc ▁for ▁New ▁Orleans , ▁Louisiana , ▁the ▁first ▁sub marine ▁to ▁traverse ▁the ▁mid - western ▁water ways ▁to ▁reach ▁New ▁Orleans ▁and ▁the ▁sea ▁from ▁the ▁building ▁yards . ▁This ▁was ▁done ▁because ▁the ▁Ch ain ▁of ▁Ro cks ▁Water way ▁as ▁well ▁as ▁some ▁of ▁the ▁pass ages ▁near ▁Chicago ▁were ▁only ▁ 9 ▁feet ▁deep , ▁whereas ▁the ▁minimum ▁draft ▁of ▁the ▁sub marine ▁was ▁ 1 2 ▁feet . ▁The ▁ship ▁recomm ission ed , ▁completed ▁fitting ▁out ▁and ▁sh aked own , ▁sa iled ▁for ▁the ▁Pan ama ▁Canal ▁and ▁arrived ▁Br is b ane , ▁Australia ▁ 1 4 ▁March ▁ 1 9 4 3 . ▁ ▁Pet o ▁depart ed ▁Br is b ane ▁for ▁her ▁first ▁war ▁pat rol ▁on ▁ 2 ▁April . ▁The ▁sub marine ▁recon no iter ed ▁Green wich ▁Island ▁for ▁sh ipping ▁on ▁the ▁ 1 3 th ▁without ▁finding ▁any ▁targets . ▁That ▁night ▁she ▁proceeded ▁toward ▁the ▁equ ator ▁to ▁cover ▁the ▁Tru k - K av ien g ▁route , ▁arriv ing ▁on ▁station ▁the ▁next ▁day . ▁A ▁south - bound , ▁Tru k - R aba ul ▁con voy ▁came ▁into ▁view ▁on ▁the ▁morning ▁of ▁ 1 7 ▁April , ▁consisting ▁of