United States Barracuda-class submarine (1951)

It was known that the Soviet Navy had acquired the German Type XXI U-boat and other advanced submarines, and was expected to rapidly put derivatives of them into production. In 1948, the US Navy prepared estimates of the number of anti-submarine warfare (ASW)-capable submarines (SSKs) that would be needed to counter the hundreds of advanced Soviet submarines that were expected to be in service by 1960. Two scenarios were considered: a reasonable scenario assuming the Soviets would build to their existing force level of about 360 submarines, and a "nightmare" scenario projecting that the Soviets could build submarines as fast as the Germans had built U-boats, with a force level of 2,000 submarines. The projected US SSK force levels for these scenarios were 250 for the former and 970 for the latter. By comparison, the total US submarine force at the end of World War II, excluding obsolescent training submarines, was just over 200 boats. ==Design==

The Barracuda-class SSKs 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 Type XXI-derived 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. The primary innovation created by Kayo was a low-frequency passive bow sonar system, the BQR-4, which was originally to be wrapped around the submarine's conning tower. Testing on showed that self-noise would greatly reduce detection range, and the sonar was relocated to the bow. Due to the large sonar dome above the torpedo tubes, in the Barracuda-class the torpedo tubes remained in their traditional bow position. ==Service==

In 1951–53, the Barracudas were joined by seven converted Gato-class SSKs. These lost four of their six bow torpedo tubes and two of their four main diesel engines. The advent of nuclear power, with entering service in 1955 and the Soviet Navy responding with the first November-class submarine only three years later, created a revolution in ASW. Nuclear submarines could maintain a high speed at deep depths indefinitely. The conventional SSKs would be useless against nuclear-powered boats, except possibly in shallow water. As nuclear attack submarines were developed and deployed, they took up the ASW mission. All ten SSKs were redesignated and decommissioned or reassigned to other duties in 1957–59. The SSK program and particularly the Barracuda class were thus overtaken by events after a few years' service. Their sonar, however, proved excellent, with good convergence zone detection ranges against snorkeling submarines; it was retained on the former Gato-class SSKs and fitted on the first nuclear submarines and a few additional diesel submarines. The bow sonar array eventually became a bow sonar sphere, with angled, amidships torpedo tubes to make room for it in the Thresher class and all subsequent US SSN classes. In 1958, Bonita was used as a nuclear weapons testing target at Eniwetok in the South Pacific, part of Operation Hardtack I. This was designed as shock testing rather than destructive testing, and damage was light except to electronics. ==Boats in class==