Sub chaser

A submarine chaser is a small and fast naval vessel that is specifically intended for anti-submarine warfare. Although similar vessels were designed and used by many nations, this designation was most famously used by ships built by the US. Many of the US World War I sub-chasers found their way to friendly powers by way of Lend-Lease in World War II.

U.S. Navy submarine chasers were designed specifically to destroy German submarines in World War I, and Japanese and German submarines in World War II. The small 110-foot (34 m) SC-1-class submarine chasers of the design used in World War I carried the hull designator SC (for Submarine Chaser). Their main weapon was the depth charge. They also carried machine guns and anti-aircraft guns. The similar-sized SC-497-class was built for World War II. Also in World War II, larger 173-foot (53 m) PC-461-class submarine chasers used the PC hull classification symbol (for Patrol, Coastal).

In early 1915, the British Admiralty selected the US Elco company for the production of 50 Motor Launches for anti-submarine work, British industry being at maximum capacity. This order was eventually increased by a further 530. The whole order was completed by November 1916, and the vessels entered Royal Navy service. The vessels were 80 feet (24 m) in length and capable of 20 knots (37 km/h). They were armed with a 3-pounder gun, towed paravanes to attack submarines and, later, depth charges. Additional motor launches of the Fairmile A and B and other classes were built for World War II.

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