Submarine: Encyclopedia II - Submarine - Military submarines

Submarine - Military submarines

There are probably more military submarines in operation than any other type of submarine, though it is difficult to obtain exact figures because navies are secretive about their submarine fleets.

Submarines are useful to a military because they are difficult to locate and, especially when deep below the surface, also difficult to destroy. A great deal of attention in the design of a submarine is devoted to making its travel through the water as silent as possible in order to prevent its detection (sound travels underwater much more easily than does light, meaning that a submarine's sound is the distinctive feature most likely to allow its detection). If a submarine remains undetected, it is able to strike at close range.

Modern submarines are usually cigar-shaped. This design, already visible on very early submarines (see below) is called a "teardrop hull", and was patterned after the bodies of whales. It significantly reduces the hydrodynamic drag on the sub when submerged, but decreases the sea-keeping capabilities and increases the drag while surfaced. Since the limitations of the propulsion systems of early military submarines forced them to operate most their time on the surface, their hull designs were a compromise. Because of the slow submerged speeds of those subs, usually well below 10 kt, the increased drag for underwater travel was considered acceptable. Only late in World War II, when technology enhancements allowed faster and longer submerged operations and increased surveillance by enemy aircraft forced submarines to stay most of their times below the surface, did hull designs become teardrop shaped again, to reduce drag and noise.

With nuclear power, submarines can remain submerged for months at a time. Diesel submarines must periodically resurface or snorkel to recharge their batteries. Some modern submarines are able to generate oxygen for their crew by electrolysis of water.

A raised tower on top of a submarine accommodates the length of the periscope and electronics masts, which can include radio, radar, electronic warfare, and other systems. In many early classes of submarines (see history, below), the Control Room, or "Conn", was located inside this tower, which was known as the "conning tower". Since that time, however, the Conn has been located within the hull of the submarine, and the tower is more commonly called the "sail" today. In another interpretation, "conning tower" comes from "to con", meaning "to navigate", as navigational systems in the conning tower. The Conn should not be confused with the "bridge", which is a small, open platform set into the top of the sail used for visual observation while operating on the surface. There may also be an additional closed platform below this with windows and wipers for bad weather.

Modern submarines use an inertial guidance system for navigation while submerged, but drift error build up over time is unavoidable. To counter this, the global positioning system will occasionally be used to obtain an accurate position. The periscope - a retractable tube with prisms allowing a view to the surface - is only used occasionally in modern submarines, since the range of visibility below the sea is short. The Virginia-class submarines have "photonics masts" rather than hull-penetrating optical tube periscopes. These masts must still be hoisted above the surface, and employ electronic sensors for visible light, infra-red, laser range-finding, and electromagnetic surveillance.

A typical nuclear submarine has a crew of over 120; non-nuclear boats typically have less than half as many. Their job is difficult because they must work in isolation for long periods of time, without much contact with their families. Submarines normally maintain radio silence to avoid detection. Operating a submarine is dangerous, even in peacetime; many submarines have been lost in accidents (see history, below).

Submarine - Types of military submarines

Non-strategic military or attack submarines may be divided in two general types: Nuclear (what the U.S. calls a fast-attack submarine; SSN) or diesel-electric (SS). Nuclear powered submarines are faster and larger, and have more firepower and longer mission endurance than diesel-electrics. Depending on the submarine's overall mission, the diesel-electric submarine is sometimes more suited for shallow water or littoral operations.

To close the gap between the two very different designs several navies have started the development of, air-independent propulsion boats which are in fact diesel-electric submarines with an enlarged diving period.

Every known strategic, ballistic-missile carrying submarine (SSBN) operated today is nuclear powered. In regard to tactical nuclear weapons, it is widely rumored that Israel tested nuclear-capable cruise missiles from two German-built Dolphin-class diesel submarines in May 2000 which thus may have reached operational capability today.

U.S. SSNs no longer carry nuclear-tipped Tomahawk cruise missiles as a result of nuclear arms control agreements. Some older, Trident class SSBN submarines are however scheduled to be converted to carry multiple conventional-warhead, "guided" Tomahawk missiles and thus become redesignated as an SSGN.

Attack submarines carrying missiles or torpedoes may be nuclear, diesel-electric or air independent powered. Currently obsolete are the tactics which called for groups of specialized submarines, such as the squadrons which contained each of the Japanese Types A, B, and C, of which the first two carried scout seaplanes, and which the first type commanded; or the US Navy's hunter-killer submarines. Other obsolete types include radar-picket submarines, such as USS Triton; specialized mine-layers; and those which carried attack seaplanes, such as the Japanese I-400-class.

Other categories include midget submarines, used for sabotage and espionage. Five of this type were used by Japan in the attack on Pearl Harbor. Another unusual category was the World War II German milchkuh submarines: submersible supply vessels.

Ballistic missile submarines (SSBNs or boomers in American slang) carry submarine-launched ballistic missiles (SLBM) with nuclear warheads, for attacking strategic targets such as cities or missile silos anywhere in the world. They are currently universally nuclear-powered, to provide the greatest stealth and endurance. (The first Soviet ballistic missile submarines were diesel-powered.) They played an important part in Cold War mutual deterrence, as both the United States and the Soviet Union had the credible ability to conduct a retaliatory strike against the other nation in the event of a first strike. This comprised the strategy of Mutual Assured Destruction.

The U.S. has 18 Ohio class submarines, of which 14 are Trident II SSBNs, each carrying 24 SLBMs. The American George Washington class "boomers" were named for "famous Americans", and together with the Ethan Allen, Lafayette, James Madison, and Benjamin Franklin classes, these SSBN's comprised the "41 for Freedom." Later Ohio class submarines were named for states (recognizing the increase in striking power and importance, equivalent to battleships), with the exceptions that some of the "famous Americans" were foreigners and SSBN-730 gained the name of a Senator. The first four Ohio class vessels were equipped with Trident I, and are now being converted to carry Tomahawk guided missiles.

For Russia, see List of NATO reporting names for ballistic missile submarines.

The British Royal Navy possess a single class of four ballistic missile submarines (what RN call "bombers", for their function), the Vanguard class. The Royal Navy's previous ballistic missile submarine class was the Resolution class which also consisted of four boats. The Resolutions, named after battleships to convey the fact they were the new capital ships, were decommissioned when the Vanguards entered service in the 1990s.

France operates a force de frappe including a nuclear ballistic submarine fleet made up of one SSBN Redoutable class and three SSBNs of the Triomphant class. One additional SSBN of the Triomphant class is under construction.

The People's Republic of China's People's Liberation Army Navy's SLBM inventory is relatively new. China launched its first nuclear armed submarine in April 1981. The PLAN currently has 5 Hans at 5,000 tons displacement and 1 Xia at roughly 8,000 tons displacement. Both are based on Soviet designs. The Type 91 is outfitted with 6 SLBM launching tubes and the Type 92 is equipped with 12. China's SLBM program is built around its JL-1 inventory. The Chinese Navy is estimated to have 24 JL-1s. The JL-1 is basically a modified DF-21.

The PLAN plans to replace its JL-1 with an unspecified number of the longer ranged, more modern JL-2s. Deployment on the JL-2 reportedly began in late 2003.

Submarines designed for the purpose of attacking merchant ships or other warships are known as "fast attacks", "hunter-killers", "fast boats", or "fleet submarines". They typically carry torpedoes for attacking naval vessels, and today carry cruise missiles for attacking either land-based targets or shipping. On American submarines, cruise missiles can be fired horizontally through a submarine's torpedo tubes, or, on newer vessels, via specially designed vertical launch tubes. The former has an effect of reducing the available torpedoes a submarine can carry, while the latter requires it to be reloaded by a submarine tender or by returning to port. The Soviet Navy also developed several types of missile attack submarines (SSGNs), which carried a heavy load of anti-surface missiles, as their primary targets were U.S. aircraft carriers.

Attack submarines can use a wide variety of propulsion systems. The majority of non-nuclear submarines use the same diesel-electric combination developed early in the 20th century, many use nuclear power, and a small but growing number use some other form of air-independent propulsion such as fuel cells or Stirling engines. All of the attack submarines of the United States use nuclear power.

All American attack submarines (that had actual names rather than just alphanumeric designators) were named for various ocean fish until the Los Angeles class, which are named for cities—with the exceptions of a few named for politicians and Hyman G. Rickover, the Seawolf class, which received the traditional name for the first, a state name for the second and a Presidential name for the third (and last), and now the Virginia class, where the first six are named after states.

Until the 1980s, Russian attack submarines were designed around the concept of Anti-Surface Warfare so they tended to be fast and noisy. Due primarily to a U.S. sailor and communications technician who spied for the Soviet Union, John Anthony Walker, Russia learned NATO naval forces could track them quite easily and over time redesigned their submarines to operate much more quietly. The Victor III was the first class of Russian submarine to be built with this new capability; armed with torpedoes, SUBROCs, and cruise missiles, they posed a more significant threat to NATO sea power. Today Russian Akula (Shark), Sierra, and Graney class submarines continue in design innovation and are respected as some of the finest submarines in the world.

Just before the 1990s, the Royal Navy consisted of diesel and nuclear powered submarines but, due to the end of the Cold War, financial cuts saw the RN submarine fleet became all-nuclear, presently consisting of the Swiftsure and Trafalgar class submarines, the latter named after the Battle of Trafalgar. The boats are armed with torpedoes, Harpoon anti-ship missiles and many are now armed with the Tomahawk cruise missile, which is fired from their torpedo tubes. The RN intends to have all of its attack submarines armed with the Tomahawk by 2008. During the Kosovo War, HMS Splendid became the first RN submarine to fire a Tomahawk in anger. The expected replacement of those classes is the Astute-class submarine, but delays have seen the expected launch of the first A class, HMS Astute, moved to 2009.

The names of Royal Navy submarine classes, including ballistic missile submarines, are letter-based; thus, all boats of the Swiftsure class begin with the letter S and the Trafalgars, the letter T. Royal Navy submarines were originally designated alphanumerically, such as HMS A1 of the A-class of 1903 (built by the pioneer designer, John P. Holland).

The role of all these attack boats has changed considerably since the end of the Cold War. U.S. fast boats no longer prowl the deep oceans in the hunt for the elusive Soviet, instead they provide cruise missile support, early warning and intelligence gathering, harbor mine clearing, Special Operation Warfare team delivery, and others. The Virginia class was specifically designed with this multiple-mission capability in mind.

Adapted from the Wikipedia article "Military submarines", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki