B57 (nuclear weapon)
Developed for the United States Navy as both a gravity bomb but, with a hydrostatic fuze, a nuclear depth charge to deal with the Cold War threat of large numbers of Soviet submarines. 3300 were produced and deployed between 1963 and 1993. large numbers were shore-based on P-3 Orion [and other [maritime patrol aircraft]], some under dual-key arrangement with NATO allies.
Many naval analysts believed that if nuclear war could be tactical and limited, the most likely scenario was in the deep ocean, in a battle between convoys and submarines.
It was replaced (without underwater capability) by the B61 bomb.
It used PBX-9404 explosive, which was found to have reliability problems.