B57

Development of the weapon began in 1960 to fulfill a requirement for a multi-purpose tactical nuclear weapon capable of functioning as either a depth charge or a ground-attack bomb. Entering production in 1963 as the Mk 57, the system was renamed the B57 in 1968. Production ran until 1967.

The weapon featured a streamlined casing designed to withstand supersonic flight. Operational configurations included versions equipped with a nylon and kevlar ribbon parachute retarder to slow descent, enabling low-altitude delivery in laydown mode or allowing the delivery aircraft to escape the blast radius. Fuzing options included a hydrostatic fuze for anti-submarine depth charge deployment. The bomb utilized the Tsetse primary core design. It was produced in six variants (Mods 0 through 5) with yields ranging from 5 to 20 kilotons: Mod 0 had a 5-kiloton yield; Mod 1 and Mod 2 had 10-kiloton yields; Mod 3 and Mod 4 had 15-kiloton yields; and Mod 5 had a 20-kiloton yield. The U.S. Navy depth bomb variant, which replaced the Mk 101 Lulu, featured a selectable yield up to 10 kilotons.

The B57 was widely deployed by the United States, Canada, and the United Kingdom. It was integrated onto U.S. fighter, bomber, and maritime patrol aircraft, including the S-3 Viking and P-3 Orion, as well as SH-3 Sea King and SH-60F Seahawk helicopters. Canadian forces operated the weapon on CF-104 aircraft based in Germany. The Royal Air Force deployed the B57 on Nimrod aircraft operating from RAF St Mawgan, RAF Kinloss, and Malta. All units of the weapon were retired from service by June 1993.