Submarines

A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. 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.

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 also be modified for specialized functions such as search-and-rescue missions and undersea cable repair. They are also 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 using A-Navigation and one- or two-person subs that operate for a few hours, to vessels that can remain submerged for six months—such as the Russian , the biggest submarines ever built. Submarines can work at greater depths than are survivable or practical for human divers.

History

Etymology

The word ''submarine'' simply means 'underwater' or 'under-sea' (as in submarine canyon, submarine pipeline) though as a noun it generally refers to a vessel that can travel underwater. The term is a contraction of ''submarine boat''. and occurs as such in several languages, e.g. French (), and Spanish (), although others retain the original term, such as Dutch (), German (), Swedish (), and Russian (: ), all of which mean 'submarine boat'. By naval tradition, submarines are still usually referred to as ''boats'' rather than as ''ships'', regardless of their size. Although referred to informally as ''boats'', U.S. submarines employ the designation USS ( United States Ship) at the beginning of their names, such as . In the Royal Navy, the designation HMS can refer to "His Majesty's Ship" or "His Majesty's Submarine", though the latter is sometimes rendered "HMS/m" For example, se
HMS/m ''Tireless''
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HMS/m ''A.1''
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Early human-powered submersibles

16th and 17th centuries

According to a report in ''Opusculum Jean Taisnier, Taisnieri'' published in 1562:

In 1578, the English mathematician William Bourne recorded in his book ''Inventions or Devises'' one of the first plans for an underwater navigation vehicle. A few years later the Scottish mathematician and theologian John Napier wrote in his ''Secret Inventions'' (1596) that "These inventions besides devises of sayling under water with divers, other devises and strategems for harming of the enemyes by the Grace of God and worke of expert Craftsmen I hope to perform." It's unclear whether he ever carried out his idea.

Jerónimo de Ayanz y Beaumont (1553-1613) created detailed designs for two types of air-renovated submersible vehicles. They were equipped with oars, autonomous floating snorkels worked by inner pumps, portholes and gloves used for the crew to manipulate underwater objects. Ayanaz planned to use them for warfare, using them to approach enemy ships undetected and set up timed gunpowder charges on their hulls.

The first submersible of whose construction there exists reliable information was designed and built in 1620 by Cornelis Drebbel, a Dutchman in the service of James I of England. It was propelled by means of oars.

18th century

By the mid-18th century, over a dozen patents for submarines/submersible boats had been granted in England. In 1747, Nathaniel Symons patented and built the first known working example of the use of a ballast tank for submersion. His design used leather bags that could fill with water to submerge the craft. A mechanism was used to twist the water out of the bags and cause the boat to resurface. In 1749, the Gentlemen's Magazine reported that a similar design had initially been proposed by Giovanni Borelli in 1680. Further design improvement stagnated for over a century, until application of new technologies for propulsion and stability.

The first military submersible was (1775), a hand-powered acorn-shaped device designed by the American David Bushnell to accommodate a single person. It was the first verified submarine capable of independent underwater operation and movement, and the first to use screws for propulsion.

19th century

In 1800, France built , a human-powered submarine designed by American Robert Fulton. They gave up on the experiment in 1804, as did the British, when they reconsidered Fulton's submarine design.

In 1850, Wilhelm Bauer's Brandtaucher was built in Germany. It remains the oldest known surviving Submarine in the world.

In 1864, late in the American Civil War, the Confederate navy's became the first military submarine to sink an enemy vessel, the Union sloop-of-war , using a gun-powder-filled keg on a spar as a torpedo charge. The ''Hunley'' also sank, as the explosion's shock waves killed its crew instantly, preventing them from pumping the bilge or propelling the submarine.

In 1866, was the first submarine to successfully dive, cruise underwater, and resurface under the crew's control. The design by German American Julius H. Kroehl (in German, ''Kröhl'') incorporated elements that are still used in modern submarines.

In 1866, was built at the Chilean government's request by Karl Flach, a German engineer and immigrant. It was the fifth submarine built in the world and, along with a second submarine, was intended to defend the port of Valparaiso against attack by the Spanish Navy during the Chincha Islands War.

Mechanically powered submarines

Submarines could not be put into widespread or routine service use by navies until suitable engines were developed. The era from 1863 to 1904 marked a pivotal time in submarine development, and several important technologies appeared. A number of nations built and used submarines. Diesel electric propulsion became the dominant power system and equipment such as the periscope became standardized. Countries conducted many experiments on effective tactics and weapons for submarines, which led to their large impact in World War I.

1863–1904

The first submarine not relying on human power for propulsion was the French (''Diver''), launched in 1863, which used compressed air at . Narcís Monturiol designed the first air-independent and combustion-powered submarine, , which was launched in Barcelona, Spain in 1864.

The submarine became a potentially viable weapon with the development of the Whitehead torpedo, designed in 1866 by British engineer Robert Whitehead, the first practical self-propelled or "locomotive" torpedo. The spar torpedo that had been developed earlier by the Confederate States Navy was considered to be impracticable, as it was believed to have sunk both its intended target, and probably ''H. L. Hunley'', the submarine that deployed it.

The Irish inventor John Philip Holland built a model submarine in 1876 and in 1878 demonstrated the Holland I prototype. This was followed by a number of unsuccessful designs. In 1896, he designed the Holland Type VI submarine, which used internal combustion engine power on the surface and electric battery power underwater. Launched on 17 May 1897 at Navy Lt. Lewis Nixon's Crescent Shipyard in Elizabeth, New Jersey, ''Holland VI'' was purchased by the United States Navy on 11 April 1900, becoming the Navy's first commissioned submarine, christened .

Discussions between the English clergyman and inventor George Garrett and the Swedish industrialist Thorsten Nordenfelt led to the first practical steam-powered submarines, armed with torpedoes and ready for military use. The first was ''Nordenfelt I'', a 56-tonne, vessel similar to Garrett's ill-fated (1879), with a range of , armed with a single torpedo, in 1885.

A reliable means of propulsion for the submerged vessel was only made possible in the 1880s with the advent of the necessary electric battery technology. The first electrically powered boats were built by Isaac Peral y Caballero in Spain (who built ), Dupuy de Lôme (who built ) and Gustave Zédé (who built ''Sirène'') in France, and James Franklin Waddington (who built ''Porpoise'') in England. Peral's design featured torpedoes and other systems that later became standard in submarines.

Commissioned in June 1900, the French steam and electric employed the now typical double-hull design, with a pressure hull inside the outer shell. These 200-ton ships had a range of over underwater. The French submarine ''Aigrette'' in 1904 further improved the concept by using a diesel rather than a gasoline engine for surface power. Large numbers of these submarines were built, with seventy-six completed before 1914.

The Royal Navy commissioned five s from Vickers, Barrow-in-Furness, under licence from the Holland Torpedo Boat Company from 1901 to 1903. Construction of the boats took longer than anticipated, with the first only ready for a diving trial at sea on 6 April 1902. Although the design had been purchased entirely from the US company, the actual design used was an untested improvement to the original Holland design using a new petrol engine.

These types of submarines were first used during the Russo-Japanese War of 1904–05. Due to the blockade at Port Arthur, the Russians sent their submarines to Vladivostok, where by 1 January 1905 there were seven boats, enough to create the world's first "operational submarine fleet". The new submarine fleet began patrols on 14 February, usually lasting for about 24 hours each. The first confrontation with Japanese warships occurred on 29 April 1905 when the Russian submarine ''Som'' was fired upon by Japanese torpedo boats, but then withdrew.

World War I

Military submarines first made a significant impact in World War I. Forces such as the U-boats of Germany saw action in the First Battle of the Atlantic, and were responsible for sinking , which was sunk as a result of unrestricted submarine warfare and is often cited among the reasons for the entry of the United States into the war.

At the outbreak of the war, Germany had only twenty submarines immediately available for combat, although these included vessels of the diesel-engined '' U-19'' class, which had a sufficient range of and speed of to allow them to operate effectively around the entire British coast., By contrast, the Royal Navy had a total of 74 submarines, though of mixed effectiveness. In August 1914, a flotilla of ten U-boats sailed from their base in Heligoland to attack Royal Navy warships in the North Sea in the first submarine war patrol in history.

The U-boats' ability to function as practical war machines relied on new tactics, their numbers, and submarine technologies such as combination diesel–electric power system developed in the preceding years. More submersibles than true submarines, U-boats operated primarily on the surface using regular engines, submerging occasionally to attack under battery power. They were roughly triangular in cross-section, with a distinct keel to control rolling while surfaced, and a distinct bow. During World War I more than 5,000 Allied ships were sunk by U-boats.

The British responded to the German developments in submarine technology with the creation of the K-class submarines. However, these submarines were notoriously dangerous to operate due to their various design flaws and poor maneuverability.

World War II

During World War II, Germany used submarines to devastating effect in the Battle of the Atlantic, where it attempted to cut Britain's supply routes by sinking more merchant ships than Britain could replace. These merchant ships were vital to supply Britain's population with food, industry with raw material, and armed forces with fuel and armaments. Although the U-boats had been updated in the interwar years, the major innovation was improved communications, encrypted using the Enigma cipher machine. This allowed for mass-attack naval tactics (''Rudeltaktik'', commonly known as " wolfpack"), but was also ultimately the U-boats' downfall. By the end of the war, almost 3,000 Allied ships (175 warships, 2,825 merchantmen) had been sunk by U-boats. Although successful early in the war, Germany's U-boat fleet suffered heavy casualties, losing 793 U-boats and about 28,000 submariners out of 41,000, a casualty rate of about 70%.

The Imperial Japanese Navy operated the most varied fleet of submarines of any navy, including '' Kaiten'' crewed torpedoes, midget submarines ( and es), medium-range submarines, purpose-built supply submarines and long-range fleet submarines. They also had submarines with the highest submerged speeds during World War II (s) and submarines that could carry multiple aircraft (s). They were also equipped with one of the most advanced torpedoes of the conflict, the oxygen-propelled Type 95. Nevertheless, despite their technical prowess, Japan chose to use its submarines for fleet warfare, and consequently were relatively unsuccessful, as warships were fast, maneuverable and well-defended compared to merchant ships.

The submarine force was the most effective anti-ship weapon in the American arsenal. Submarines, though only about 2 percent of the U.S. Navy, destroyed over 30 percent of the Japanese Navy, including 8 aircraft carriers, 1 battleship and 11 cruisers. US submarines also destroyed over 60 percent of the Japanese merchant fleet, crippling Japan's ability to supply its military forces and industrial war effort. Allied submarines in the Pacific War destroyed more Japanese shipping than all other weapons combined. This feat was considerably aided by the Imperial Japanese Navy's failure to provide adequate escort forces for the nation's merchant fleet.

During World War II, 314 submarines served in the US Navy, of which nearly 260 were deployed to the Pacific.O'Kane, p. 333 When the Japanese attacked Hawaii in December 1941, 111 boats were in commission; 203 submarines from the , , and es were commissioned during the war. During the war, 52 US submarines were lost to all causes, with 48 directly due to hostilities. US submarines sank 1,560 enemy vessels, a total tonnage of 5.3 million tons (55% of the total sunk).Blair, p. 878

The Royal Navy Submarine Service was used primarily in the classic Axis blockade. Its major operating areas were around Norway, in the Mediterranean (against the Axis supply routes to North Africa), and in the Far East. In that war, British submarines sank 2 million tons of enemy shipping and 57 major warships, the latter including 35 submarines. Among these is the only documented instance of a submarine sinking another submarine while both were submerged. This occurred when engaged ; the ''Venturer'' crew manually computed a successful firing solution against a three-dimensionally maneuvering target using techniques which became the basis of modern torpedo computer targeting systems. Seventy-four British submarines were lost, the majority, forty-two, in the Mediterranean.

Cold-War military models

The first launch of a cruise missile (SSM-N-8 Regulus) from a submarine occurred in July 1953, from the deck of , a World War II fleet boat modified to carry the missile with a nuclear warhead. ''Tunny'' and its sister boat, , were the United States' first nuclear deterrent patrol submarines. In the 1950s, nuclear power partially replaced diesel–electric propulsion. Equipment was also developed to extract oxygen from sea water. These two innovations gave submarines the ability to remain submerged for weeks or months. Most of the naval submarines built since that time in the US, the Soviet Union/ Russian Federation, Britain, and France have been powered by nuclear reactors.

In 1959–1960, the first ballistic missile submarines were put into service by both the United States () and the Soviet Union () as part of the Cold War nuclear deterrent strategy.

During the Cold War, the US and the Soviet Union maintained large submarine fleets that engaged in cat-and-mouse games. The Soviet Union lost at least four submarines during this period: was lost in 1968 (a part of which the CIA retrieved from the ocean floor with the Howard Hughes-designed ship ''Glomar Explorer''), in 1970, in 1986, and in 1989 (which held a depth record among military submarines—). Many other Soviet subs, such as (the first Soviet nuclear submarine, and the first Soviet sub to reach the North Pole) were badly damaged by fire or radiation leaks. The US lost two nuclear submarines during this time: due to equipment failure during a test dive while at its operational limit, and due to unknown causes.

During India's intervention in the Bangladesh Liberation War, the Pakistan Navy's sank the Indian frigate . This was the first sinking by a submarine since World War II. During the same war, , a ''Tench''-class submarine on loan to Pakistan from the US, was sunk by the Indian Navy. It was the first submarine combat loss since World War II. In 1982 during the Falklands War, the Argentine cruiser was sunk by the British submarine , the first sinking by a nuclear-powered submarine in war. Some weeks later, on 16 June, during the Lebanon War, an unnamed Israeli submarine torpedoed and sank the Lebanese coaster ''Transit'', which was carrying 56 Palestinian refugees to Cyprus, in the belief that the vessel was evacuating anti-Israeli militias. The ship was hit by two torpedoes, managed to run aground but eventually sank. There were 25 dead, including her captain. The Israeli Navy disclosed the incident in November 2018.

21st century

Usage

Military

Before and during World War II, the primary role of the submarine was anti-surface ship warfare. Submarines would attack either on the surface using deck guns, or submerged using torpedoes. They were particularly effective in sinking Allied transatlantic shipping in both World Wars, and in disrupting Japanese supply routes and naval operations in the Pacific in World War II.

Mine-laying submarines were developed in the early part of the 20th century. The facility was used in both World Wars. Submarines were also used for inserting and removing covert agents and military forces in special operations, for intelligence gathering, and to rescue aircrew during air attacks on islands, where the airmen would be told of safe places to crash-land so the submarines could rescue them. Submarines could carry cargo through hostile waters or act as supply vessels for other submarines.

Submarines could usually locate and attack other submarines only on the surface, although managed to sink with a four torpedo spread while both were submerged. The British developed a specialized anti-submarine submarine in WWI, the R class. After WWII, with the development of the homing torpedo, better sonar systems, and nuclear propulsion, submarines also became able to hunt each other effectively.

The development of submarine-launched ballistic missile and submarine-launched cruise missiles gave submarines a substantial and long-ranged ability to attack both land and sea targets with a variety of weapons ranging from cluster bombs to nuclear weapons.

The primary defense of a submarine lies in its ability to remain concealed in the depths of the ocean. Early submarines could be detected by the sound they made. Water is an excellent conductor of sound (much better than air), and submarines can detect and track comparatively noisy surface ships from long distances. Modern submarines are built with an emphasis on stealth. Advanced propeller designs, extensive sound-reducing insulation, and special machinery help a submarine remain as quiet as ambient ocean noise, making them difficult to detect. It takes specialized technology to find and attack modern submarines.

Active sonar uses the reflection of sound emitted from the search equipment to detect submarines. It has been used since WWII by surface ships, submarines and aircraft (via dropped buoys and helicopter "dipping" arrays), but it reveals the emitter's position, and is susceptible to counter-measures.

A concealed military submarine is a real threat, and because of its stealth, can force an enemy navy to waste resources searching large areas of ocean and protecting ships against attack. This advantage was vividly demonstrated in the 1982 Falklands War when the British nuclear-powered submarine sank the Argentine cruiser . After the sinking the Argentine Navy recognized that they had no effective defense against submarine attack, and the Argentine surface fleet withdrew to port for the remainder of the war, though an Argentine submarine remained at sea.

Civilian

Although the majority of the world's submarines are military, there are some civilian submarines, which are used for tourism, exploration, oil and gas platform inspections, and pipeline surveys. Some are also used in illegal activities.

The Submarine Voyage ride opened at Disneyland in 1959, but although it ran under water it was not a true submarine, as it ran on tracks and was open to the atmosphere. The first tourist submarine was , which went into service in 1964 at Expo64. By 1997 there were 45 tourist submarines operating around the world. Submarines with a crush depth in the range of are operated in several areas worldwide, typically with bottom depths around , with a carrying capacity of 50 to 100 passengers.

In a typical operation a surface vessel carries passengers to an offshore operating area and loads them into the submarine. The submarine then visits underwater points of interest such as natural or artificial reef structures. To surface safely without danger of collision the location of the submarine is marked with an air release and movement to the surface is coordinated by an observer in a support craft.

A recent development is the deployment of so-called narco-submarines by South American drug smugglers to evade law enforcement detection. Although they occasionally deploy true submarines, most are self-propelled semi-submersibles, where a portion of the craft remains above water at all times. In September 2011, Colombian authorities seized a 16-meter-long submersible that could hold a crew of 5, costing about $2 million. The vessel belonged to FARC rebels and had the capacity to carry at least 7 tonnes of drugs.

File:PX-8 Mésoscaphe - Swiss Submarine (15722856966).jpg, Model of the Mésoscaphe ''Auguste Piccard''
File:AtlantisSubInterior3497.JPG, Interior of the tourist submarine ''Atlantis'' whilst submerged
File:AtlantisVIISubmarineClip3494.jpg, Tourist submarine ''Atlantis''

Polar operations

* 1903 – Simon Lake submarine ''Protector'' surfaced through ice off Newport, Rhode Island.McLaren, Alfred S., CAPT USN "Under the Ice in Submarines" ''United States Naval Institute Proceedings'' July 1981, pp. 105–9
* 1930 – operated under ice near Spitsbergen.
* 1937 – Soviet submarine ''Krasnogvardeyets'' operated under ice in the Denmark Strait.
* 1941–45 – German U-boats operated under ice from the Barents Sea to the Laptev Sea.
* 1946 – used upward-beamed fathometer in Operation Nanook in the Davis Strait.
* 1946–47 – used under-ice sonar in Operation High Jump in the Antarctic.
* 1947 – used upward-beamed echo sounder under pack ice in the Chukchi Sea.
* 1948 – developed techniques for making vertical ascents and descents through polynyas in the Chukchi Sea.
* 1952 – used an expanded upward-beamed sounder array in the Beaufort Sea.
* 1957 – reached 87 degrees north near Spitsbergen.
* 3 August 1958 – ''Nautilus'' used an inertial navigation system to reach the North Pole.
* 17 March 1959 – surfaced through the ice at the north pole.
* 1960 – transited under ice over the shallow ( deep) Bering-Chukchi shelf.
* 1960 – transited the Northwest Passage under ice.
* 1962 – Soviet reached the north pole.
* 1970 – carried out an extensive undersea mapping survey of the Siberian continental shelf.
* 1971 – reached the North Pole.
* conducted three Polar Exercises: 1976 (with US actor Charlton Heston aboard); 1984 joint operations with ; and 1990 joint exercises with .
* 6 May 1986 – , and meet and surface together at the Geographic North Pole. First three-submarine surfacing at the Pole.
* 19 May 1987 – joined and at the North Pole.
* March 2007 – participated in the Joint US Navy/ Royal Navy Ice Exercise 2007 (ICEX-2007) in the Arctic Ocean with the .
* March 2009 – took part in Ice Exercise 2009 to test submarine operability and war-fighting capability in Arctic conditions.

Technology

Buoyancy and trim

All surface ships, as well as surfaced submarines, are in a positively buoyant condition, weighing less than the volume of water they would displace if fully submerged. To submerge hydrostatically, a ship must have negative buoyancy, either by increasing its own weight or decreasing its displacement of water. To control their displacement and weight, submarines have ballast tanks, which can hold varying amounts of water and air.

For general submersion or surfacing, submarines use the main ballast tanks (MBTs), which are ambient pressure tanks, filled with water to submerge, or with air to surface. While submerged, MBTs generally remain flooded, which simplifies their design, and on many submarines these tanks are a section of the space between the light hull and the pressure hull. For more precise control of depth, submarines use smaller depth control tanks (DCTs)—also called hard tanks (due to their ability to withstand higher pressure), or trim tanks. These are variable buoyancy pressure vessels, a type of buoyancy control device. The amount of water in depth control tanks can be adjusted to hydrostatically change depth or to maintain a constant depth as outside conditions (mainly water density) change. Depth control tanks may be located either near the submarine's center of gravity, to minimise the effect on trim, or separated along the length of the hull so they can also be used to adjust static trim by transfer of water between them.

When submerged, the water pressure on a submarine's hull can reach for steel submarines and up to for titanium submarines like , while interior pressure remains relatively unchanged. This difference results in hull compression, which decreases displacement. Water density also marginally increases with depth, as the salinity and pressure are higher. This change in density incompletely compensates for hull compression, so buoyancy decreases as depth increases. A submerged submarine is in an unstable equilibrium, having a tende