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Submarine

A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability.[1] The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as boats rather than ships irrespective of their size.[2]

This article is about watercraft designed for submerged operation. For other uses, see Submarine (disambiguation).

Although experimental submarines had been built earlier, submarine design took off during the 19th century, and they were adopted by several navies. They were first widely used during World War I (1914–1918), and are now used in many navies, large and small. Military uses include attacking enemy surface ships (merchant and military) or other submarines, and for aircraft carrier protection, blockade running, nuclear deterrence, reconnaissance, conventional land attack (for example, using a cruise missile), and covert insertion of special forces. Civilian uses include marine science, salvage, exploration, and facility inspection and maintenance. Submarines can be modified for specialized functions such as search-and-rescue missions and undersea cable repair. They are used in tourism and undersea archaeology. Modern deep-diving submarines derive from the bathyscaphe, which evolved from the diving bell.


Most large submarines consist of a cylindrical body with hemispherical (or conical) ends and a vertical structure, usually located amidships, that houses communications and sensing devices as well as periscopes. In modern submarines, this structure is the "sail" in American usage and "fin" in European usage. A "conning tower" was a feature of earlier designs: a separate pressure hull above the main body of the boat that allowed the use of shorter periscopes. There is a propeller (or pump jet) at the rear, and various hydrodynamic control fins. Smaller, deep-diving, and specialty submarines may deviate significantly from this traditional design. Submarines dive and resurface by means of diving planes and changing the amount of water and air in ballast tanks to affect their buoyancy.


Submarines encompass a wide range of types and capabilities. They include small autonomous examples, such as one- or two-person subs that operate for a few hours, to vessels that can remain submerged for six months—such as the Russian Typhoon class, the biggest submarines built. Submarines can work at greater depths than are survivable or practical for human divers.[3]

Civilian submarines

Interior of the tourist submarine Atlantis whilst submerged

Interior of the tourist submarine Atlantis whilst submerged

Tourist submarine Atlantis

Tourist submarine Atlantis

It entails a loss of fuel-efficiency as well as power by converting the output of the diesel engine into electricity. While both generators and electric motors are known to be very efficient, their efficiency nevertheless falls short of 100 percent.

It requires an additional component in the form of a dedicated generator. Since the electric motor is always used to drive the propeller it can no longer step in to take on generator service as well.

It does not allow the diesel engine and the electrical motor to join forces by simultaneously driving the propeller mechanically for maximum speed when the submarine is surfaced or snorkeling. This may, however, be of little practical importance inasmuch as the option it prevents is one that would leave the submarine at a risk of having to dive with its batteries at least partly depleted.

List of submarine operators

Australia –

Collins-class submarine

Bangladesh-

Submarines of the Bangladesh Navy

Britain – , List of submarine classes of the Royal Navy

List of submarines of the Royal Navy

China –

Submarines of the People's Liberation Army Navy

Germany –

List of U-boats of Germany

India –

Submarines of the Indian Navy

Israel –

Dolphin-class submarine

The Netherlands –

List of submarines of the Netherlands

Pakistan –

List of active Pakistan Navy ships § Submarines

Romania –

Romanian submarines of World War II

Russia – , Future Russian submarines

List of Soviet and Russian submarine classes

Soviet Union –

List of ships of the Soviet Navy § Submarines

Spain –

List of submarines of the Spanish Navy

Singapore –

Republic of Singapore Navy § Submarines

Turkey –

List of submarines of the Turkish Navy

Submarine boat

U.S. patent 708,553

is available for free viewing and download at the Internet Archive

The Submarine: Part II: Construction (1955)

US Navy submarine training manuals, 1944–1946

The Fleet Type Submarine Online

American Society of Safety Engineers. Journal of Professional Safety. Submarine Accidents: A 60-Year Statistical Assessment. C. Tingle. September 2009. pp. 31–39. ; or Reproduction without graphics/tables

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