Written by Norman Cramp, Director of the Darwin Military Museum.
The depth charge is effective against the submarine by being dropped, or launched, into the sea and detonating at a set depth following which the submarine is subjected to powerful and destructive hydraulic shock.
Most depth charges utilise high explosive charges loaded into to the body of the device which is ignited by means of a fuse set to activate at a certain depth.
Each depth charge creates another shock wave until such time as the submarine’s hull fractures and begins to take on water. Many submarines sink outright whilst others surface with the intent of either fighting off the attackers or allowing the crew to escape before the submarine is scuttled.
They remained on ‘active service’ throughout the Cold War but as no fighting erupted, there is no record of any being deployed.