A midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to nine, with little or no on-board living accommodation. They normally work with mother ships, from which they are launched and recovered and which provide living accommodation for the crew and support staff.
Both military and civilian midget submarines have been built. Military types work with surface ships and other submarines as mother ships. Civilian and non-combatant military types are generally called submersibles and normally work with surface ships. Most early submarines would now be considered midget submarines, such as the United States Navy's and the British Royal Navy's (both named for the same designer).
Military submarines
Uses
Midget submarines are best known for harbor penetration, although only two World War II boats, the British X-craft and the unsuccessful Welman submarine, were specifically designed with this in mind. Japan's Ko-hyoteki-class submarines were originally designed to take part in decisive fleet actions. However, as circumstances changed, they were given the task of harbor penetration. Germany's various World War II designs were mostly designed to attack Allied shipping off landing beaches and harbors, although the Seehund had a great enough range to attack shipping off the Thames estuary.
Midget submarines have also seen some use in support roles. X-craft were used for reconnaissance, and the Seehund was used to carry supplies. A number of modern midget submarines have also been built for submarine rescue.
Armament Midget submarines are commonly armed with torpedoes and mines in the form of, for example, detachable side loads and nose sections. Alternatively they may function as swimmer delivery vehicles to deliver frogmen to the vicinity of their targets, which are then attacked with limpet mines.
Civilian In civilian use, midget submarines are generally called submersibles; commercial submersibles are used in, for example, underwater maintenance, exploration, archaeology, and scientific research. Other commercially available submersibles are marketed as novelty tourist attractions and as specialised tenders for wealthy yacht owners. Also, a growing number of amateur submariners homebuilt submersibles as a hobby.
Types by nation
Belgium FNRS-2 pioneering research submersible
Colombia S.X.506 a 70-ton 5-man crew midget submarine designed by Italian shipbuilder Cosmos as a development of earlier S.X.404 by the same firm. Displacement is 58/70 t (surfaced/submerged), length is 23 m, beam is 2 m, draft is 4 m, and speed is 8.5/7 kn (surfaced/submerged). At a speed of 7 kn, range is 1200/60 nmi (surfaced/submerged). Payload includes externally attached torpedoes and swimmer delivery vehicles, and up to 8 divers can be carried in addition to the 5-man crew.
USSR and Finland MIR for research and submarine rescue
France FNRS-3 research submersible Archimède research submersible FNRS-4 second generation research submersible Nautile research submersible to depth of 6 kilometers SP-350 Denise diving saucer
France also acquired a number of German midget submarines at the end of WW2.
Germany
Most German midget submarines were developed late in World War II in an attempt to stop the Allied liberation of Europe and used later to disrupt its supply lines. As a result, the submarines mostly engaged in open water attacks rather than harbour penetration. Biber (324 built by AG Weser of Bremen)Lenton, H.T. GERMAN WARSHIPS of the Second World War Arco Publishing (1976) pp. 285–286 Delphin (2 built) 2-man 5-ton torpedo with top speed of and submerged radius of at . Hai (midget submarine) prototype of improved Marder. Hecht type XXVIIA 2-man 12 ton submarine with 1 mine or 1 torpedo carried outboard to a range of 38 miles at 4 knots.Taylor, J.C. German Warships of World War II Doubleday & Company (1967) p. 109 Marder (~300 built) similar to Neger with breathing apparatus to allow submerged operation. Molch Completely electric motor driven WWII (1944–1945) Midget submarine. Total 393 built. Schwertwal (Grampus) Designed as super-fast Walter-type midget boat, but the prototype was not complete when scuttled in May 1945. Neger (~200 built) 1-man 5-ton torpedo with underslung G7E torpedo. Top speed 20 knots and range of 30 miles at 3 knots. Seehund type XXVIIBTaylor, J.C. German Warships of World War II Doubleday & Company (1967) p.110 Most successful midget submarine in the Kriegsmarine. Operational deployment was between January 1945 – April 1945. V.80 4-man 76-ton prototype completed in 1940 to test Walther geared turbine propulsion system. Range was at .Lenton, H.T. GERMAN WARSHIPS of the Second World War Arco Publishing (1976) p.212 Orca class post-war midget submarine: 13.27 meter x 2.1 meter 5 men midget submarine with maximum depth of 100, maximum underwater speed of 5 kn, maximum range of 150 nmi, maximum endurance of 4 days, and maximum payload of 250 kg. Periscopes includes television camera, HF/HF communication and GPS antenna. There is also an underwater television camera and obstacle avoidance sonar with an effective range of 200 m. The low acoustic and magnetic signature midget sub displaces 28 t, powered by two computerized permanent magnetic electric motors that drive a single shaft low-cavitation and low noise propeller, which is controlled by fly-by-wire control system that is usually adopted for aircraft. The pressure hull is a modular design consisted of four modules that enables easy transportation and maintenance.
India The Indian Navy is planning to acquire two midget submarines at an estimated cost of ₹2000 Crores for use as swimmer delivery vehicles. These submarines will be used for conducting underwater special operations by MARCOS. Both submarines will be constructed by Hindustan Shipyard Limited.
Indonesia The Indonesian Navy has shown some interest in having a new Midget-class submarine, built by local shipyards, for coastal rather than open water patrol. The submarine was designed a number of years ago by a retired Indonesian Navy submariner officer, Colonel (Ret) Ir. R. Dradjat Budiyanto, Msc. The midget experiment project involves the construction of a submarine, designated MIDGET IM X −1, which will weigh about 150 – 250 tonnes, with a tubular frame design 24 – 30 meters long, and four torpedo tubes. The submarines will have minimum of 8 – 10 crew members including officers. They will have a 40 km range non-hull-penetrating optronic mast as the attack periscope, and a 20 km range navigation periscope.
Indonesian defence minister Purnomo Yusgiantoro has backed the project. Construction should commence at the Indonesian PT.PAL INDONESIA shipyard by late 2011, and will take about three or four years to complete.
Iran Ghadir Nahang Khomaini
Italy
Siluro a Lenta Corsa (SLC), also known as Maiale (pig), a low speed human torpedo. On 3 December 1941, Sciré departed La Spezia carrying three Maiale to conduct what became the Raid on Alexandria (1941). At the island of Leros in the Aegean Sea, six Decima Flottiglia MAS crewmen came aboard, including Lieutenant Luigi Durand de la Penne. On December 18 Sciré released the manned torpedoes 1.3 miles from Alexandria commercial harbor, and they entered the harbor when the British opened the boom defence to let three of their destroyers pass. After many difficulties, de la Penne and his crewmate Emilio Bianchi successfully attached a limpet mine under , but had to surface as they attempted to leave and were captured. They refused to answer when questioned and were detained in a compartment aboard Valiant. Fifteen minutes before the explosion, de la Penne asked to speak to the Valiants captain and informed him of the imminent explosion but refused to give other information. He was returned to the compartment and neither he or Bianchi were injured by the detonation of the mine. The other four torpedo-riders were also captured, but their mines sank Valiant, the battleship , the Norwegian tanker Sagona and badly damaged the destroyer . The two battleships sank in only a few feet of water and were subsequently re-floated. Nevertheless, they were out of action for over a year. Bathyscaphe Trieste was first to explore the Challenger Deep of the Mariana Trench CA type First series was a 2-man midget submarine the second series carried a crew of three. CB type 45 ton 4 man design first introduced in 1941 CE2F/X100 post-war torpedo chariot MG 120: MG 120 Shallow water attack submarine (SWATS) is a development of MG 110 in Pakistani service with the displacement is increased to 130 t submerged, range is 1600 nmi @ 7 kn surfaced, 60 nmi @ 4.5 kn submerged, and the number of divers carried is drastically increased to 15. MG 130: MG 130 is a development of MG 120 with AIP module called UAPE (Underwater Auxiliary Propulsion Engine) based on a closed circuit diesel fueled by liquid oxygen, which provides an underwater range of 400 nmi (740 km).
Japan
Type A Kō-hyōteki-class midget submarines were used in the 1941 attack on Pearl Harbor, the 1942 attack on Sydney Harbour, and the 1942 Allied attack on Diego Suarez Harbor, in which the type 97 torpedo was used operationally. The wreckage of one of the submarines sunk at Pearl Harbor was located by NOAA's Hawaii Undersea Research Laboratory (HURL) in August 2002. Photographic analysis conducted by the United States Naval Institute in 1999 indicated that one of the five Ko-hyoteki-class submarines managed to enter Pearl Harbor, and successfully fired a torpedo into . On 29 May 1942, one of two midget submarines managed to enter the Diego Suarez harbor and fire two torpedoes. One torpedo seriously damaged the battleship , while the second sank the oil tanker British Loyalty (6,993 tons).
Type B Kō-hyōteki-class Midget Ha 45 prototype built 1942 to test Type A improvements.Watts, Anthony J. Japanese Warships of World War II Doubleday & Company (1967) p.213 Type C Kō-hyōteki-class Midget Ha 62–76 similar to Type A with crew of 3 and range increased to at surfaced or at submerged. Type D Kō-hyōteki-class, also called Kōryū class (115 completed) improved Type C with crew of 5 and range increased to at surfaced and at submerged.Watts, Anthony J. Japanese Warships of World War II Doubleday & Company (1967) p.216
Kaiten submarine suicide torpedo. DSV Shinkai research submersible, capable of diving to a depth of
North Korea Yugo-class submarine Yono-class submarine (see also ROKS Cheonan sinking)
South Korea S.X.756: Developed by Italian shipbuilder Cosmos as a successor of earlier S.X.506 midget submarine in Colombian service. Length is increased to 25.2 m and beam is increased to 2.1 m in comparison to its predecessor S.X.506, and displacement is increased to 73/80 t (surfaced/submerged). Crew is increased by one to a total of 6, but the total number of divers carried remained the same at 8. Range is 1600 nmi @ 6 kn surfaced, and 60 nmi @ 4 kn submerged, and payload remains the same. Dolgorae class midget sub
Pakistan MG 110: Developed by Italian shipbuilder Cosmos as a successor of earlier S.X.756 midget submarine in South Korean service. MG 110 is a slightly enlarged version of S.X.756 with length increased to 27.28 m, diameter increased to 2.3 m, and displacement increased to 102/110 t (surfaced/submerged). Range is 1200 nmi surfaced, and the submerged range remain the same. Payload and crew are also identical to that of its predecessor S.X.756 midget submarine.
China Type 7103 DSRVs Osprey class submersibles Sea Pole class bathyscaphe Dragon class bathyscaphe Harmony class bathyscaphe Mobile diving bell QSZ-II submersible
Poland Blotniak
Taiwan 2 Italian Cos.Mo.S CE2F/X100 post-war torpedo chariots