 They were meant as a stopgap measure to counter the threat of an ever-growing fleet of Soviet attack submarines.The entire fleet was retired when larger destroyers were introduced, permitting the use of manned helicopters to launch the same kind of torpedo, and the use of more powerful rocket-assisted torpedo systems.If UAVs could be used for reconnaissance by the army and the air force, it was obvious that they could also be used for active combat missions, at least in principle.