▁the ▁m idget s ▁while ▁the ▁mother ▁ships ▁were ▁sub mer ged ▁prevent ed ▁the ▁Army ▁coast al ▁rad ars ▁from ▁detect ing ▁the ▁mother ▁sub mar ines . ▁However , ▁the ▁m idget s ▁were ▁still ▁difficult ▁to ▁control , ▁un stable , ▁and ▁pr one ▁to ▁sur f acing ▁or ▁div ing ▁un cont roll ably . ▁These ▁man oe uv rab ility ▁issues ▁contributed ▁to ▁M - 1 4 s ▁ent ang lement ▁in ▁the ▁anti - sub marine ▁net , ▁and ▁the ▁repeated ▁detection ▁of ▁M - 2 1 ▁and ▁M - 2 4 . ▁ ▁Bey ond ▁the ▁use ▁of ▁the ▁un re li able ▁m idget s , ▁histor ians ▁have ▁identified ▁areas ▁in ▁the ▁plan ▁of ▁attack ▁where ▁the ▁Japanese ▁could ▁have ▁done ▁significantly ▁more ▁damage . ▁If ▁the ▁Japanese ▁m idget ▁sub mar ines ▁had ▁conducted ▁a ▁simultane ous , ▁co - ordin ated ▁attack , ▁they ▁would ▁have ▁over wh el med ▁the ▁def ences . ▁A ▁chance ▁for ▁more ▁damage ▁came ▁following ▁the ▁destruction ▁of ▁K ut tab ul , ▁when ▁several ▁naval ▁vessels ▁head ed ▁to ▁sea , ▁including ▁USS ▁Chicago , ▁USS ▁Per kins , ▁Dutch ▁sub marine ▁K - IX , ▁H MA S ▁Why alla , ▁and ▁H M IS ▁Bomb ay . ▁The ▁five ▁mother ▁sub mar ines ▁were ▁already ▁en ▁route ▁to ▁the ▁Port ▁H ack ing ▁recovery ▁position , ▁and ▁although ▁S as aki ' s ▁plan ▁at ▁Pear l ▁Har bor ▁had ▁been ▁to ▁leave