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 otherwise operating independently. When operating within a fleet, cruisers and cruiser submarines could be expected to scout for and screen the battle fleet. Cruiser submarines were successful for a brief period of

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, but were less successful than smaller submarines during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. 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 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. The use of unrestricted submarine warfare has had significant impacts on international relations in ...

campaign of 1917. Three

German Type U 139 submarine U-139, originally designated "Project 46", was a class of large, long-range U-boats built during World War I by the Kaiserliche Marine. Description Three large U-cruisers, designated Type 139, were ordered from Germaniawerft of Kiel, in August ...

s 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 running, or to dive under Arctic ice. Strictly ...

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

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

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 the union of the Kingdom of Great Britain and the Kingdom of Ireland into one sovereign state, established by the Acts of Union 1800, Acts of Union in 1801. It continued in this form until ...

. 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 an archipelago in the Atlantic Ocean, 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 Hebrides, Inner and Outer Hebr ...

. The First World War combat experience of these submarines encouraged all major navies to build submarine cruiser

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototype ...

s between the world wars, but their cost discouraged most from further production. Developments were further limited by the

London Naval Treaty The London Naval Treaty, officially the Treaty for the Limitation and Reduction of Naval Armament, was an agreement between the United Kingdom, Empire of Japan, Japan, French Third Republic, France, Kingdom of Italy, Italy, and the United Stat ...

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, notably the types including the types J, A, B, and C. 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 w ...

s, including Type IXD2 U-boats and

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

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 ...

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