▁against ▁US ▁batt les hips ▁during ▁the ▁attack ▁on ▁Pear l ▁Har bor . ▁The ▁n avy ▁hoped ▁that ▁up gr ades ▁to ▁the ▁sub mar ines , ▁intens ified ▁crew ▁training , ▁and ▁the ▁selection ▁of ▁a ▁less ▁well ▁def ended ▁target ▁would ▁lead ▁to ▁better ▁results ▁and ▁an ▁increased ▁chance ▁of ▁the ▁cre ws ▁of ▁the ▁m idget s ▁to ▁return ▁alive ▁from ▁their ▁mission . ▁Therefore , ▁on ▁ 1 6 ▁December ▁ 1 9 4 1 , ▁the ▁n avy ▁initi ated ▁plans ▁for ▁a ▁second ▁m idget ▁sub marine ▁operation . ▁ ▁The ▁plans ▁called ▁for ▁two ▁simultane ous ▁attacks ▁against ▁Al lied ▁naval ▁vessels ▁in ▁the ▁Indian ▁and ▁South ▁Pacific ▁o ce ans . ▁These ▁attacks ▁were ▁intended ▁as ▁divers ions ▁ahead ▁of ▁the ▁attack ▁on ▁Mid way ▁Island ▁in ▁the ▁North ▁Pacific , ▁with ▁the ▁Japanese ▁hoping ▁to ▁conv ince ▁the ▁Al lies ▁that ▁they ▁intended ▁to ▁attack ▁to ▁the ▁south ▁or ▁west ▁of ▁their ▁con quest s . ▁Ele ven ▁sub mar ines ▁of ▁the ▁ 8 th ▁Sub marine ▁Squadron ▁were ▁to ▁carry ▁out ▁the ▁two ▁attacks , ▁the ▁five ▁sub mar ines ▁of ▁the ▁Western ▁Att ack ▁Group ▁in ▁the ▁Indian ▁Ocean , ▁and ▁the ▁six ▁sub mar ines ▁of ▁the ▁Eastern ▁Att ack ▁Group ▁in ▁the ▁Pacific ▁Ocean . ▁The ▁sub marine ▁groups ▁were ▁to ▁select ▁a ▁suitable ▁port ▁of ▁attack , ▁based ▁on ▁their ▁own ▁reconna issance . ▁ ▁The ▁Western ▁Att ack ▁Group ▁selected ▁the ▁port ▁of ▁Di é go