The XE-class submarines were a series of twelve midget submarines that were built for the Royal Navy during 1944; four more to a slightly different design were built 1954-5 as the Stickleback class. They were an improved version of the used in the attack on the German battleship . They carried a crew of four, typically a lieutenant in command, with a sub-lieutenant as deputy, an engine room artificer in charge of the mechanical side and a seaman or leading-seaman. At least one of them was qualified as a diver. In addition to the two side charges (each of which contained two tons of amatol explosive), they carried around six limpet mines which were attached to the target by the diver. They and their depot ship arrived at Labuan in July 1945. Four of them managed to take part in operations before the war ended. Operations Sabre and Foil These operations, carried out in July 1945, were intended to cut the undersea telephone cables connecting Singapore, Saigon, Hong Kong and Tokyo. The intention was to oblige the Japanese to use radio and render themselves open to message interception. Operation Sabre was directed at the Hong Kong to Saigon telephone cable, and carried out by XE4, which was towed to within of the Mekong Delta by the submarine HMS Spearhead, where she looked for the two telephone cables by using a towed grapnel. She eventually snagged the first cable, and managed to haul it about off the seabed. XE4's diver, Sub-Lieutenant K.M. Briggs, used the net/cable cutter to sever it. The second cable was soon found as well, and was severed by the second diver, Sub-Lieutenant A. Bergius. Two divers were carried due to the operating rule that a diver should not spend more than 20 minutes in depths over and no more than 10 minutes over . XE4 and Spearhead returned to Labuan on 3 August 1945. Operation Foil was directed at the Hong Kong to Singapore telephone cable and carried out by XE5 against the Hong Kong end of the cable, after being towed into position by the submarine HMS Selene. Operating close inshore near to Lamma Island, working conditions were poor, XE5's divers having to work in thick mud under the constant threat of oxygen poisoning. Despite repeated attempts it was not completely certain that the cable had in fact been severed, and it was not until after