A cruiser submarine was a very large submarine designed to remain at sea for extended periods in areas distant from base facilities. Their role was analogous to surface cruisers, cruising distant waters, commerce raiding, and scouting for the battle fleet. Cruiser submarines were successful for a brief period of

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

, but were less successful than smaller submarines during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. Large submarines remained vulnerable to damage from defensively equipped merchant ships (DEMS), were slow to dive if found by aircraft, offered a large

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on o ...

echo surface, and were less able to defensively maneuver during depth charge attacks.Blair, p.501

History

The cruiser submarine concept originated during the

unrestricted submarine warfare Unrestricted submarine warfare is a type of naval warfare in which submarines sink merchant ships such as freighters and tankers without warning, as opposed to attacks per prize rules (also known as "cruiser rules") that call for warships to s ...

campaign of 1917. Three German Type U 139 submarines and seven former

merchant submarines A merchant submarine is a type of submarine intended for trade, and being without armaments, it is not considered a warship like most other types of submarines. The intended use would be Blockade runner, blockade running, or to dive under Sea ice ...

, each armed with two guns, patrolled areas distant from their

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...

bases to sink Allied merchant shipping as part of an effort to end World War I by starving the

United Kingdom of Great Britain and Ireland The United Kingdom of Great Britain and Ireland was a sovereign state in the British Isles that existed between 1801 and 1922, when it included all of Ireland. It was established by the Acts of Union 1800, which merged the Kingdom of Grea ...

. These distant patrols enjoyed unique immunity to the defensive

convoy A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support and can help maintain cohesion within a unit. It may also be used ...

measures which limited successful submarine attacks in the vicinity of the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...

. The First World War combat experience of these submarines encouraged all major navies to build submarine cruiser prototypes between the world wars, but their cost discouraged most from further production. Developments were further limited by the London Naval Treaty of 1930, under which each signatory was permitted to possess no more than three large submarines, each above 2,000 tons (2,032 metric tons) but not exceeding 2,800 tons (2,845 metric tons) standard displacement, with guns not exceeding 6.1 in (150 mm) in caliber. Japanese focus on the distances of their Pacific trade routes encouraged development of the widest variety of submarine cruisers, including the A, B and J types. Germany decided against building projected 3,140-ton type XI U-boats with an aircraft hangar and four guns.Lenton, pp.198&199 Long-range submarines with less impressive

deck gun A deck gun is a type of naval artillery mounted on the deck of a submarine. Most submarine deck guns were open, with or without a shield; however, a few larger submarines placed these guns in a turret. The main deck gun was a dual-purpose ...

s, including Type IXD2 U-boats and

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

fleet submarine A fleet submarine is a submarine with the speed, range, and endurance to operate as part of a navy's battle fleet. Examples of fleet submarines are the British First World War era K class and the American World War II era ''Gato'' class. The t ...

s, evolved through the Second World War; and may be identified as cruiser submarines in comparison to submarines designed for shorter patrols over lesser distances.

Examples

Notes

Sources

* * * * * * * * * * * {{Warship types of the 19th & 20th centuries Submarines by type