The ''Stickleback''-class submarines were

midget submarine A midget submarine (also called a mini 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, ...

s of the British

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...

initially ordered as improved versions of the older s. They were designed to allow British defences to practice defending against midget submarines since it was theorised that the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

had or could develop such craft. The Royal Navy developed plans to use these craft to carry a 15-kiloton nuclear

naval mine A naval mine is a self-contained explosive device placed in water to damage or destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, any ...

(based on the Red Beard weapon) codenamed Cudgel into Soviet harbours. The project was unsuccessful as there were problems finding and paying for the necessary fissile material.

Boats

There were four boats, launched 1954–1955:Gardiner and Chumbley, p. 527 *X51 ''Stickleback'', launched 1 October 1954, sold to the Royal Swedish Navy in 1958 and was renamed ''Spiggen'' (Swedish name for "Stickleback"). After a period on display at the Imperial War Museum Duxford, and then in storage at Portsmouth Naval Dockyard, X51 was moved to the

Scottish Submarine Centre The Scottish Submarine Centre (SSC) is a submarine Maritime museum, naval museum in west Scotland. History It opened on 11 November 2017. Structure It is situated on the A818 road (Great Britain), A818. See also * Royal Navy Submarine Museum in ...

in Helensburgh, where it has been on display since 2018. *X52 ''Shrimp'', launched October 1954, scrapped 1965 *X53 ''Sprat'', launched 30 December 1954, loaned to US Navy 1958, scrapped 1966 *X54 ''Minnow'', launched 5 May 1955, scrapped 1966

References

* * Submarine classes {{UK-mil-submarine-stub