Limbo, or Anti Submarine Mortar Mark 10 (A/S Mk.10), was the final British development of a forward-throwing anti-submarine weapon originally designed during the Second World War. Limbo, a three-barreled mortar similar to the earlier Squid and Hedgehog that it superseded, was developed by the Admiralty Underwater Weapons Establishment in the 1950s. Squid was loaded manually, which was difficult on a pitching deck in heavy seas with no protection from the elements; in contrast Limbo was loaded and fired automatically, with all the crew under cover. It was widely fitted on the quarterdeck of Royal Navy escort ships on a mounting stabilised for pitch and roll from 1955 to the mid–1980s. Australian built versions of the Daring-class destroyer all carried Limbo as did the Australian River-class