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." The three Barracuda ASW boats were not the only US submarines to bear the hull classification symbol SSK. USS Croaker (SS-246) (SSK-246) was a converted World War II Gato class submarine.

The primary innovation created by Kayo was a low-frequency passive bow sonar system, the BQR-4. With the sonar array occupying the boat's bow, the forward torpedo tubes had to be moved back and angled outward.

The Barracuda type SSK's were designed to be smaller than contemporary attack submarines and simpler in design and construction. It was hoped that this would allow them to be cheaply mass-produced in the large numbers it was thought would be needed to combat the growing Soviet submarine fleet. It was also thought that this would allow shipyards without submarine experience, and aircraft contractors with experience in the mass production of large complex aircraft, to build these submarines.

Like other attempts to build smaller, cheaper submarines, the experiment was a failure. As with the pre-World War II Mackerel class, and later USS Tullibee (SSN-597), the result was a ship with insufficient performance to meet their intended operational usage. The Barracudas were slow and had limited endurance, and so were retired by the late 1950s. Their sonar, however, proved excellent, with good convergence zone detection ranges against snorkeling submarines. A bow sonar array and angled, amidships torpedo tubes have been used in every submarine design created since the Barracudas.