▁two ▁destroy ers , ▁two ▁medium ▁fre igh ters , ▁and ▁one ▁small ▁auxili ary . ▁However , ▁before ▁Pet o ▁attacked , ▁the ▁trailing ▁destroy er ▁detected ▁the ▁sub marine ▁and ▁forced ▁her ▁to ▁d ive . ▁She ▁with stood ▁nine ▁depth ▁charges ▁without ▁damage . ▁ ▁On ▁ 5 ▁May , ▁she ▁made ▁a ▁night ▁attack ▁conducted ▁by ▁sound ▁and ▁rad ar ▁alone , ▁firing ▁three ▁tor ped o es ▁at ▁a ▁target ▁for ▁one ▁possible ▁hit . ▁After ▁pat rolling ▁off ▁Cape ▁Oxford , ▁Pet o ▁head ed ▁for ▁Br is b ane ▁on ▁ 2 0 ▁May . ▁ ▁Pet o ▁depart ed ▁on ▁her ▁second ▁war ▁pat rol ▁on ▁ 1 0 ▁June . ▁On ▁ 2 9 ▁June , ▁she ▁fired ▁two ▁tor ped o es ▁at ▁a ▁small ▁auxili ary . ▁One ▁tor ped o ▁hit ▁near ▁the ▁bow , ▁breaking ▁the ▁ship ▁in ▁two . ▁On ▁ 7 ▁July , ▁she ▁sight ed ▁an ▁east - bound ▁tank er ▁similar ▁to ▁N ipp on ▁Mar u ▁with ▁two ▁esc ort ing ▁destroy ers . ▁Pet o ▁man eu ver ed ▁and ▁fired ▁three ▁tor ped o es ; ▁two ▁hits ▁causing ▁severe ▁damage . ▁She ▁returned ▁to ▁Br is b ane ▁on ▁ 4 ▁August . ▁ ▁On ▁ 1 ▁September , ▁Pet o ▁set ▁out ▁on ▁her ▁third ▁war ▁pat rol , ▁which ▁was ▁held ▁in ▁the ▁area ▁north ▁of ▁the ▁B ism ar ck ▁Arch ip el ago . ▁After ▁recon no iter