United States Barracuda-class submarine (1951)
The Barracuda-class submarines were the product of Project Kayo, a research and development effort begun immediately after World War II by the United States Navy to "solve the problem of using submarines to attack and destroy enemy submarines." They originally had the hull classification symbol SSK, for "hunter-killer submarine".
USS Bass
An attack submarine or hunter-killer submarine is a submarine specifically designed for the purpose of attacking and sinking other submarines, surface combatants and merchant vessels. In the Soviet and Russian navies they were and are called "multi-purpose submarines". They are also used to protect friendly surface combatants and missile submarines. Some attack subs are also armed with cruise missiles, increasing the scope of their potential missions to include land targets.
HMCS Windsor, an attack submarine of the Royal Canadian Navy
USS K-3 with BQR-4 sonar dome
K-5, a Soviet November-class SSN, the threat that made Western conventional SSKs obsolete
USS Thresher, the first high-speed deep-diving SSN optimized for both ASW and surface attack