, ▁and ▁a ▁lim pet ▁mine ▁in ▁the ▁nose . ▁ ▁Extern ally , ▁He cht ▁res emble d ▁the ▁British ▁Wel man ▁sub marine . ▁The ▁det ach able ▁explos ive ▁charge ▁was ▁fitted ▁to ▁the ▁nose ▁of ▁the ▁sub marine , ▁while ▁the ▁forward ▁section ▁held ▁the ▁battery ▁and ▁a ▁gy ro comp ass , ▁the ▁first ▁to ▁be ▁fitted ▁to ▁a ▁German ▁m idget ▁sub marine ▁and ▁considered ▁essential ▁for ▁navigation ▁since ▁the ▁craft ▁was ▁intended ▁to ▁operate ▁almost ▁exclus ively ▁below ▁the ▁surface . ▁Be hind ▁this ▁was ▁the ▁control ▁compart ment ▁with ▁seats ▁for ▁the ▁two ▁man ▁crew ▁arranged ▁one ▁behind ▁the ▁other ▁on ▁the ▁centre line ▁with ▁the ▁engineer ▁in ▁front ▁and ▁the ▁commander ▁behind ▁him . ▁The ▁commander ▁was ▁provided ▁with ▁a ▁per is cope ▁and ▁a ▁clear ▁ac ry lic ▁d ome ▁for ▁navig ational ▁purposes . ▁ ▁On ▁ 1 8 ▁January ▁ 1 9 4 4 , ▁D ön itz ▁discussed ▁the ▁new ▁design ▁with ▁Adolf ▁Hitler ▁who ▁expressed ▁his ▁appro val , ▁and ▁on ▁ 9 ▁March ▁contract s ▁were ▁placed ▁with ▁Germania wer ft ▁of ▁K iel ▁for ▁construction ▁of ▁a ▁prototype , ▁followed ▁by ▁a ▁further ▁contract ▁for ▁ 5 2 ▁sub mar ines ▁on ▁ 2 8 ▁March . ▁ ▁Fif ty - three ▁He chts ▁were ▁built ▁in ▁total ▁between ▁May ▁and ▁August ▁ 1 9 4 4 , ▁but ▁their ▁uns atisf actory ▁performance ▁meant ▁they ▁never ▁saw ▁action , ▁and ▁were ▁mostly ▁used ▁for ▁training ▁See