Depth charge

A depth charge is an anti-submarine warfare (ASW) weapon intended to destroy or cripple a target submarine by being dropped into the water close to its target and detonating, subjecting the target to a powerful and destructive hydraulic shock. Most depth charges use high explosive charges and a fuze set to detonate the charge typically at a preselected depth. Depth charges can be dropped by ships, patrol aircraft, and helicopters. Depth charges have now largely been replaced by anti-submarine homing torpedoes.

A depth charge fitted with a nuclear warhead is known as a "nuclear depth bomb". These were designed to be dropped from a patrol plane or deployed by an anti-submarine missile from a surface ship, or another submarine, located a safe distance away. All nuclear anti-submarine weapons were withdrawn from service by the United States, the United Kingdom, France, Russia, and China in or around 1990. They were replaced by conventional weapons whose accuracy and range had improved greatly as ASW technology improved.