▁surface ▁ste ering ▁to ▁the ▁east ward . ▁Three ▁depth ▁charges ▁were ▁dropped ▁ahead ▁of ▁the ▁U - Bo at ▁and ▁across ▁her ▁b ows . ▁The ▁centre ▁depth ▁charge ▁of ▁the ▁stick , ▁set ▁at ▁ 2 5 ▁feet , ▁expl oded ▁immediately ▁under ▁the ▁U - Bo at , ▁which ▁was ▁not ▁seen ▁again . ▁The ▁details ▁of ▁the ▁U - Bo at ' s ▁disapp earance ▁could ▁not ▁be ▁observed ▁as ▁U ▁ 4 5 1 ▁was ▁en velop ed ▁in ▁the ▁sp ray ▁of ▁the ▁depth - charge ▁explos ions . ▁Two ▁large ▁oil ▁patch es ▁were ▁seen , ▁each ▁ 3 0 0 ▁yards ▁in ▁diameter ." ▁The ▁sole ▁surv iving ▁crew ▁member , ▁Ober le ut nant ▁zur ▁See ▁( L ie utenant ) ▁Walter ▁Kö h ler , ▁stated ▁that ▁he ▁was ▁on ▁the ▁bridge ▁with ▁three ▁ratings ▁at ▁the ▁time ▁of ▁the ▁attack , ▁and ▁that ▁the ▁noise ▁of ▁the ▁dies el ▁engines ▁obsc ured ▁the ▁sound ▁of ▁the ▁attack ing ▁aircraft ▁until ▁the ▁moment ▁of ▁weapons ▁release . ▁He ▁was ▁unable ▁to ▁get ▁inside ▁the ▁vessel ▁before ▁the ▁h atch ▁was ▁closed . ▁" He ▁stated ▁that ▁the ▁U - bo at ▁then ▁s ank ▁b ows ▁down . ▁The ▁prisoner ▁fl ung ▁himself ▁into ▁the ▁water ▁and ▁sw am ▁for ▁an ▁hour ▁and ▁a ▁half ▁before ▁he ▁was ▁picked ▁up ▁by ▁My os ot is ." ▁ ▁References ▁ ▁Bibli ography ▁ ▁External ▁links ▁ ▁Category : G erman ▁Type ▁VII C ▁sub