A midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to six or 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 USS Holland (SS-1) and the British Royal Navy's HMS Holland 1 (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

Colombia

Finland

France

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 invasion 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.

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

Italy

Japan

North Korea

South Korea

Pakistan

China

Poland

Taiwan

Romania

Russia

Spain

Sweden

Turkey

The Turkish navy has evaluated two midget submarine designs from German firm ThyssenKrupp Marine Systems, Type 200 and Type 300 classes:

United Kingdom

The Royal Navy has used a number of midget submarines. Most were developed during the Second World War. The decommissioning of the Stickleback class 1958–early 1960s marked the end of midget submarines designed for combat in the Royal Navy.

United States

Former Yugoslavia