▁sur fac ed , ▁she ▁could ▁travel ▁ ▁at ▁. ▁U - 6 1 3 ▁was ▁fitted ▁with ▁five ▁ ▁tor ped o ▁tub es ▁( four ▁fitted ▁at ▁the ▁bow ▁and ▁one ▁at ▁the ▁stern ), ▁four teen ▁tor ped o es , ▁one ▁ ▁SK ▁C / 3 5 ▁naval ▁gun , ▁ 2 2 0 ▁r ounds , ▁and ▁a ▁ ▁C / 3 0 ▁anti - air craft ▁gun . ▁The ▁boat ▁had ▁a ▁complement ▁of ▁between ▁forty - four ▁and ▁si xty . ▁ ▁Service ▁history ▁The ▁boat ' s ▁career ▁began ▁with ▁training ▁at ▁ 8 th ▁U - bo at ▁Fl ot illa ▁on ▁ 1 2 ▁March ▁ 1 9 4 2 , ▁followed ▁by ▁active ▁service ▁on ▁ 1 ▁November ▁ 1 9 4 2 ▁as ▁part ▁of ▁the ▁ 1 st ▁Fl ot illa ▁for ▁the ▁remainder ▁of ▁her ▁service . ▁ ▁In ▁four ▁pat rol s ▁she ▁s ank ▁two ▁merchant ▁ships , ▁for ▁a ▁total ▁of ▁. ▁ ▁Wolf pack s ▁U - 6 1 3 ▁took ▁part ▁in ▁six ▁w olf pack s , ▁namely ▁ ▁N atter ▁( 2 – 8 ▁November ▁ 1 9 4 2 ) ▁ ▁West wall ▁( 8 – 1 8 ▁November ▁ 1 9 4 2 ) ▁ ▁Hab icht ▁( 1 0 – 1 9 ▁January ▁ 1 9 4 3 ) ▁ ▁H au de gen ▁( 1 9 ▁January ▁– ▁ 9 ▁February ▁ 1 9 4 3 ) ▁