depth

A depth charge is an anti-submarine warfare (ASW) weapon designed to destroy submarines by detonating in the water near the target and subjecting it to a destructive hydraulic shock. Most depth charges use high explosives with a fuze set to detonate the charge, typically at a specific depth from the surface. Depth charges can be dropped by ships (typically fast, agile surface combatants such as destroyers or frigates), patrol aircraft and helicopters.
Depth charges were developed during World War I, and were one of the first viable methods of attacking a submarine underwater. They were widely used in World War I and World War II, and remained part of the anti-submarine arsenals of many navies during the Cold War, during which they were supplemented, and later largely replaced, by anti-submarine homing torpedoes.

A depth charge fitted with a nuclear warhead is also 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. By the late 1990s all nuclear anti-submarine weapons had been withdrawn from service by the United States, the United Kingdom, France, Russia and China. They have been replaced by conventional weapons whose accuracy and range had improved greatly as ASW technology improved.

View More On Wikipedia.org