▁the ▁esc ort s ▁depth ▁charg ing ▁C eros ▁position . ▁After ▁closing ▁C ero ▁slowly , ▁she ▁fired ▁two ▁r ounds ▁from ▁her ▁ ▁deck ▁gun ▁at ▁the ▁esc ort s , ▁and ▁as ▁the ▁esc ort s ▁returned ▁the ▁fire ▁she ▁with d rew , ▁giving ▁C ero ▁a ▁chance ▁to ▁escape ▁un har med . ▁ ▁On ▁ 2 3 ▁February , ▁Pet o ▁sa iled ▁for ▁Lang em ak ▁Bay ▁to ▁ref uel ▁and ▁obtain ▁spare ▁parts , ▁arriv ing ▁on ▁ 2 7 ▁February . ▁On ▁ 1 ▁March , ▁she ▁head ed ▁for ▁her ▁area ▁again , ▁and ▁on ▁ 3 ▁March ▁made ▁an ▁un success ful ▁attack ▁on ▁an ▁enemy ▁merchant man . ▁The ▁next ▁day , ▁she ▁fired ▁six ▁tor ped o es ▁at ▁a ▁cargo ▁ship ▁and ▁then ▁went ▁deep ▁to ▁listen ▁as ▁esc ort s ▁were ▁near . ▁Two ▁hits ▁were ▁heard , ▁followed ▁by ▁a ▁loud , ▁deep ▁explos ion . ▁Three ▁minutes ▁later ▁breaking ▁up ▁no ises ▁were ▁heard , ▁and ▁spl ash es ▁from ▁de br is ▁falling ▁in ▁the ▁water ▁could ▁be ▁heard ▁for ▁several ▁minutes . ▁The ▁esc ort s ▁dropped ▁ 1 3 ▁depth ▁charges ▁before ▁giving ▁up . ▁Pet o ▁had ▁s unk ▁Kay o ▁Mar u . ▁On ▁ 1 6 ▁March , ▁Pet o ▁set ▁course ▁for ▁Mid way ▁At oll ▁where ▁she ▁arrived ▁on ▁ 2 5 ▁March . ▁She ▁sa iled ▁on ▁for ▁Pear l ▁Har bor ▁the ▁same ▁day , ▁arriv