Meanwhile, the British had a fascinating series of anti-submarine weapons. The problem with depth charges dropped off the stern was that you had to pass over t

Meanwhile, the British had a fascinating series of anti-submarine weapons. The problem with depth charges dropped off the stern was that you had to pass over the target before firing, telegraphing your shot, losing sonar contact and firing nearly blind. The British came up with the "Hedgehog" system to fire mortars forward. It was also a shotgun approach, firing several at a time in a spread, those that hit exploding on contact (rather than by depth). Hedgehog "destroy[ed] the target in about 20 percent of attacks in the Atlantic (versus 6 percent of depth charge attacks in the same theater.)"[1] There were few reloads, though, and sometimes the smaller charges failed to sink the target. Then someone realized that if you set off explosions on opposite sides of a sub, you create a pressure wave that just collapses the target like an empty can of soda. That's how "Squid" worked. Its charges also sank about twice as fast as the hedgehogs, speeding up resolution. There was a single and a double squid system, the double system brought the success rate up to around 40 percent.[2] Loading and firing munitions can be difficult in a storm or a battle. So the natural improvement in "Limbo" was to automate all that, with sonar officers pointing the system to a target and pulling the trigger.[3] There's some stock footage of Limbo out there.[4] [1] http://pwencycl.kgbudge.com/H/e/Hedgehog.htm http://pwencycl.kgbudge.com/H/e/Hedgehog.htm [2] http://www.navweaps.com/Weapons/WAMBR_ASW.htm http://www.navweaps.com/Weapons/WAMBR_ASW.htm [3] The Squid and the Limbo automatically corrected for pitch and roll, but the Limbo ensured that the munitions would enter the water at the same angle, which simplified the detonation timing. The Limbo system was in use up to the 1990s. [4] http://www.criticalpast.com/video/65675054412_NATO-Operation-Strikeback_Limbo-mortar_British-ASW-Frigate_Semiautomatic-loading_chain-rammers http://www.criticalpast.com/video/65675054412_NATO-Operation...