submarine - torpedo, pistol - ?

BULLET
WordClue
BOWtorpedo - submarine, arrow - ?
ARROWsubmarine - torpedo, bow - ?
PISTOLtorpedo - submarine, bullet - ?
WEAPONbow or pistol
TORPEDOpistol - bullet, submarine - ?
WARSHIPcorvette or submarine
SUBMARINEbullet - pistol, torpedo - ?
ARROWsubmarine - torpedo, bow - ?
OBEYANCEsubmission, acquiescence