Midget submarine

A midget submarine ia a small submarine, typically with a one or two person crew and with no on-board living accommodation. Midget submarines normally work with mother ships from which they are launched and recovered, and which provide living accommodation for the crew and other support.

Both military and civilian midget submarines have been built and operated. Military types have worked using both surface ships and submarines as mother ships. Civilian and non-combatant military types are generally referred to as submersibles, and normally work with surface ships.

Five Ko-hyoteki class midget submarines were used in the 1941 attack on Pearl Harbour, the only occasion on which the type 97 torpedo was used operationally. Another famous attack by midget submarines was launched by the Japanese Navy against Sydney in 1942, this time using more conventional type 91 torpedoes. Of four two-person midget submarines launched on that occasion, only one returned to rendezvous with its mother ship submarine. Two were destroyed by depth charges and recovered by Australian defenders, the fourth remains lost.

The term midget submarine has also been applied to the Japanese Kaiten and Kairyu suicide weapons of the Second World War, which were both single-use munitions armed only with a fixed warhead. The Kaiten was more accurately a heavy torpedo modified by the rough addition of a one or two person pilot's cabin. The Kairyu, which was produced in significant numbers but never used operationally, had conventional gasoline and electric propulsion, and is normally regarded as a submarine. The Ko-hyoteki class submarine carried two light torpedos in muzzle-loaded 17.7 inch torpedo tubes one above the other, and was intended to return to the mother ship for rearming after these were fired. Its fixed explosive charge was intended only for its own demolition to avoid capture.

The Royal Navy also used a number of midget submarines. The first group (known as the X class were used to attack German warships in the North of Norway. A particular target of a successful attack was the battleship Tirpitz. They had a crew of three and carried two large mines, one each side. The idea was to lay the mines on the sea bottom underneath the target, set a time fuze and depart.

The later XE class were used in the Far East and a number of attacks and special missions were carried out.

The british also developed the Welman class a single person submarine which is widely considered to have been a failure.

The German Navy also had some inluding the Biber. They were used against the D-Day invasion fleet but do not seem to have achieved very much.

See also submersible, Ko-hyoteki class submarine, human torpedo.