The Fairlie Mortar was an unsuccessful British anti-submarine mortar design of the early second World War. It projected small anti-submarine bombs simultaneously, ten from each side of the ship's forecastle, each containing 20 lb (9.1 kg) of explosive. The Fairlie Mortar was not a success and 'Hedgehog', a spigot mortar projecting 24 small bombs from a platform, eventually became the predominant British ship-borne anti-submarine weapon in the war.