SUBMAR

INE

A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term most commonly refers to a large, crewed, autonomous vessel. It 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. Used as an adjective in phrases such as submarine cable, "submarine" means "under the sea". The noun submarine evolved as a shortened form of submarine boat (and is often further shortened to sub).[1] For reasons of naval tradition, submarines are usually referred to as "boats" rather than as "ships", regardless of their size.Although experimental submarines had been built before, submarine design took off during the 19th century, and they were adopted by several navies. Submarines were first widely used during World War I (1914–1918), and now figure in many navies large and small. Military usage includes attacking enemy surface ships (merchant and military), submarines, aircraft carrier protection, blockade running, ballistic missile submarines as part of a nuclear strike force, reconnaissance, conventional land attack (for example using a cruise missile), and covert insertion of special forces

αMost large submarines consist of a cylindrical body with hemispherical (and/or conical) ends and a vertical structure, usually located amidships, which 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.

α 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 layout.

α Submarines change the amount of water and air in their ballast tanks to decrease buoyancy for submerging or increase it for surfacing.

Submarines have one of the widest ranges of types and capabilities of any vessel. They range from small autonomous examples and one or two-person vessels that operate for a few hours, to vessels that can remain submerged for six months—such as the Russian Typhoon class, the biggest submarines ever built. Submarines can work at greater depths than are survivable or practical for human divers. Modern deep-diving submarines derive from the bathyscaphe, which in turn evolved from the diving bell.

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.

The first military submarine was the Turtle (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.[6] In 1800, France built a human-powered submarine designed by American Robert Fulton, the Nautilus.

The French eventually gave up on the experiment in 1804, as did the British when they later considered Fulton's submarine design.

HistoryDrebbel, the first navigable submarineAccording to a report attributed to Tahbir al-Tayseer in Opusculum Taisnieri published in 1562:Two Greeks submerged and surfaced in the river Tagus near the City of Toledo several times in the presence of The Holy Roman Emperor Charles V, without getting wet and with the flame they carried in their hands still alight.

There are claims that Cosme García Sáez produced a viable submersible design predating those of Isaac Peral and Narciso Monturiol.

The first submersible of whose construction there exists reliable information was built in 1620 by Cornelius Drebbel, a Dutchman in the service of James I of England. It was created to the standards of the design outlined by English mathematician William Bourne.

It was propelled by means of oars. The precise nature of the submarine type is a matter of some controversy; some claims suggest it was merely a bell towed by a boat.

β In 1864, late in the American Civil War, the Confederate navy's H. L. Hunley became the first military submarine to sink an enemy vessel, the Union sloop-of-war USS Housatonic. In the aftermath of its successful attack against the ship, the Hunley also sank, possibly because it was too close to its own exploding torpedo.

Mechanical powerβThe first submarine not relying on human power for propulsion was the French Plongeur (Diver), launched in 1863, and using compressed air at 180 psi (1241 kPa).

βThe first air independent and combustion powered submarine was the Ictineo II, designed by the Spanish intellectual, artist and engineerNarcís Monturiol. Launched in Barcelona in 1864, it was originally human-powered, but in 1867 Monturiol invented an air independent engine to power it underwater.

βThe 14 m (46 ft) long craft was designed for a crew of two, performed dives of 30 m (98 ft) and remained underwater for two hours. Both the Ictineo I and II were double-hulled vessels that solved pressure and buoyancy control problems that had troubled and limited the functionality of earlier submarines.

The Nordenfelt-designed, Ottomansubmarine Abdül HamidLike Resurgam, Nordenfelt I operated on the surface by steam, then shut down its engine to dive. While submerged the submarine released pressure generated when the engine was running on the surface to provide propulsion for some distance underwater. Greece, fearful of the return of the Ottomans, purchased it.

Nordenfelt then built Nordenfelt II (Abdül Hamid) in 1886 and Nordenfelt III (Abdül Mecid) in 1887, a pair of 30 metre (100 ft) submarines with twin torpedo tubes, for the Ottoman navy. Abdülhamid became the first submarine in history to fire a torpedo submerged.

Nordenfelt's efforts culminated in 1887 with Nordenfelt IV, which had twin motors and twin torpedoes. It was sold to the Russians, but proved unstable, ran aground, and was scrapped.

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 James Franklin Waddington in England, Dupuy de Lôme and Gustave Zédé in France and Isaac Peral in Spain.

The Gymnote was launched by the French Navy in the same year. Gymnote was also an electrically powered and fully functional military submarine. It completed over 2,000 successful dives using a 204-cell battery.

Although the Gymnote was scrapped for its limited range, its side hydroplanes became the standard for future submarine designs.

Modern submarinesAkula (launched in 1907) was the first Russian submarine able to cruise long distances. Wreck nearHiiumaa, Estonia.Submarines were not put into service for any widespread or routine use by navies until the early 1900s. The turn of the century marked a pivotal time in submarine development, and a number of 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.

USS Plunger, launched in 1902€The Irish inventor John Philip Holland built a model submarine in 1876 and a full scale one in 1878, followed by a number of unsuccessful ones. In 1896 he designed the Holland Type VI submarine.

€This vessel made use of internal combustion engine power on the surface and electric battery power for submerged operations.

€ Launched on 17 May 1897 at Navy Lt. Lewis Nixon's Crescent Shipyard inElizabeth, New Jersey, the Holland VI was purchased by the United States Navy on 11 April 1900, becoming the United States Navy's first commissioned submarine and renamed USS Holland.

The German submarine SM U-9, which sank three British cruisers in less than an hour in September 1914.

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 the sinking of RMS Lusitania, 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 very outbreak of war Germany had only 20 submarines immediately available for combat, although these included vessels of the diesel-engined U-19 class with the range (5,000 miles) and speed (eight knots) 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.

HMS Astute is among the most advanced nuclear submarines.Nuclear power is now used in all large submarines, but due to the high cost and large size of nuclear reactors, smaller submarines still use diesel-electric propulsion.

The ratio of larger to smaller submarines depends on strategic needs. The US Navy, French Navy, and the British Royal Navy operate only nuclear submarines, which is explained by the need for distant operations. Other major operators rely on a mix of nuclear submarines for strategic purposes and diesel-electric submarines for defense. Most fleets have no nuclear submarines, due to the limited availability of nuclear power and submarine technology.

Diesel-electric submarines have a stealth advantage over their nuclear counterparts. Nuclear submarines generate noise from coolant pumps and turbo-machinery needed to operate the reactor, even at low power levels.[51] Some nuclear submarines such as the American Ohio class can operate with their reactor coolant pumps secured, making them quieter than electric subs.

A conventional submarine operating on batteries is almost completely silent, the only noise coming from the shaft bearings, propeller, and flow noise around the hull, all of which stops when the sub hovers in mid-water to listen, leaving only the noise from crew activity. Commercial submarines usually rely only on batteries, since they never operate independently of a mother ship.

The largest submarine in us navyThe Ohio class is a class of nuclear-powered submarines used by the United States Navy. The navy has 18 Ohio-class submarines: 14 ballistic missile submarines (SSBN) and four that were later converted to guided missile submarines (SSGN).

The Ohio class is named after the lead submarine of this class, USS Ohio. The 14 Trident II SSBNs together carry approximately fifty percent of the total US active inventory of strategic thermonuclear warheads.

The exact number of warheads deployed across the world varies in an unpredictable and classified manner,[citation needed] but always at or below a maximum number set by various Strategic Arms Reduction Treaties.

Trident missiles have no pre-set targets when the submarines go on patrol[citation needed], the warships, when required, are capable of quickly being assigned targets by using secure and constant radio communications links at sea, including very low frequency (VLF) systems.

All the Ohio-class submarines, except for USS Henry M. Jackson (SSBN-730), are named for U.S. states, which until that point was a tradition reserved for battleships and cruisers.

The Ohio-class submarines are the largest submarines ever built for the U.S. Navy. Two classes of the Russian Navy's submarines have larger total displacements: the Soviet-designed Typhoon-class submarines have more than twice the total displacement, and Russia's Borei-class submarines have roughly 25 percent greater displacement, but the Ohio-class warships carry more missiles than either of the other designs: 24 Trident missiles per boat, versus 16 missiles for the Borei class (20 for the Borei II) and 20 for the Typhoon-class.

The idea of traveling underneath the ocean waters inside a contained vessel has been around for centuries. Legend says Alexander the Great ventured below the waters of the Aegean Sea inside a glass barrel around 333 B.C. He is reported to have seen whales and deep-sea life on his underwater journey.

The next record of a submarine came more than 1900 years later. In 1578 A.D., British naval officer William Bourne described a wooden frame vessel enclosed in waterproof leather, which could be rowed underwater. Bourne's creation was never realized.

In 1904, the French built the Aigrette, the first submarine to use a diesel engine on the surface and an electric engine below. The United States followed in 1911 with the F-class Skipjack. It too was powered by diesel instead of gas engines.

How they functionTo function underwater, submarines are built a bit differently than surface ships that float on the water's surface.

In order to travel underwater, submarines must function in agreement with some key laws of nature, including Archimedes' Principle and Boyles' Law.

Submarines are completely enclosed vessels with cylindrical shapes, narrowed ends and two hulls: the inner hull and the outer hull.

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