Submarine

A submarine (the word originally meant under the sea) is a boat that is built to be operated under water for extended periods of time. The first known treatise on submarines (also called subs) was written in 1578. Published by English mathematician William Bourne (1535–1582) in his Inventions or Devices, the document describes a ship with two hulls, the outer made of wood. While no record exists concerning its manufacture, the ship, according to Bourne, could be submerged or raised by taking in or expelling water from between the double hulls. Dutch inventor Cornelius Drebbel (1572–1633) built the first known submarine. It consisted of greased leather over a wooden framework. It was propelled either on or beneath the surface by eight oars sealed through the sides with leather flaps. During a demonstration for James I (1603–1625) in 1620, this vessel was successfully piloted just under the surface of the Thames River. It was unable, however, to make deep descents.

During the American Revolution, American inventor David Bushnell (1742–1824) built a one-person submarine called the Turtle. It resembled an egg squashed thin with a height of 6 ft (2 m), and had two hand-cranked screw propellers, a hand-operated control lever connected to the rudder, foot-operated pumps to let water in or send it out (to submerge or surface), and a crudely lit control panel. As if it was not dangerous enough simply to get in the water sealed inside this

device, the Turtle also had a large explosive device attached to it in the hopes the operator could maneuver under an enemy ship, screw the explosive into the ship’s hull, and depart before the explosive’s timing device discharged it. Unfortunately, the Turtle failed to sink any ship. On its only test mission, the Turtle was assigned the task of bombing the British HMS Eagle off the waters of New York City, but its pilot was unable to screw the explosive into the Eagle’s copper hull.

Others, such as English carpenters Nathaniel Symons and J. Day, included ballast systems on their submarines to permit descents. Day’s submarine resembled a sloop, and had two large bags of stones hanging from its bottom to serve as ballast. Day would sink, then jettison the rocks to return to the surface. After two successful tests, Day confidently decided he would test his vessel off Plymouth Sound, a site with a depth of 900 ft (274 m). Apparently his ship was crushed by high water pressure, for when he and his crew descended, a crowd of onlookers waited in vain for his return. Day and his crew had become the first victims of a submarine mishap.

Perhaps the most successful early submarine was designed by American engineer and inventor Robert Fulton (1765–1815). In an age of naval battles, Fulton, who detested war, felt that a device capable of neutralizing the effectiveness of warships would end war altogether. While living in France in 1767, he outlined plans to build a sub called the Nautilus and unsuccessfully attempted to interest the French government in his idea. By 1801, however, he had managed to complete a submarine on his own. A 21 ft (6 m) vessel with a two-bladed propeller, the Nautilus performed well in tests, even sinking a ship with an explosive charge. But he was once again rejected by the French government, so he moved to England, hoping for a better reception there.

It soon became clear that the English did not want his submarine either. In fact, Fulton had failed not because his vessel did not work, but because major naval powers feared his vessel and did not want to participate in developing a weapon that could negate their military strength. Fulton went on to produce his famous steamboats in the United States.

After the American Civil War (1861–1865), designers, spurred on by the invention of the self-propelled torpedo in 1866, increasingly sought alternatives to human-powered propulsion for submarines. Several systems proved unsuitable—steam engines made the craft unbearably hot and an electric battery could not be recharged at sea. In the late 1890s, however, Irish-born American engineer John Philip Holland (1841– 1914) solved the problem with the use of a new power source, the gasoline engine. Because it needed oxygen, the gasoline engine could not be used while a submarine was underwater, but on the surface it could not only provide propulsion but also charge the batteries used while submerged. Holland’s vessels incorporated many of the features engineers associate with modern subs: a powerful engine, advanced control and balancing systems, and a circular-shaped hull to withstand pressure. The United States Navy accepted his submarine, the Holland, in 1900.

Around this time, two other improvements were introduced. Simon Lake (1866–1945), who also built an early gasoline-powered submarine, created the first periscope specifically for submarines: it provided a magnified view and a wide angle of vision. In the 1890s, German inventor Rudolf Diesel (1858–1913) invented an engine that was fired by compression rather than an electric spark. The diesel engine was more economical than the gasoline engine and its fumes were much less toxic and volatile. This new engine became the mainstay of all submarines until nuclear power was introduced as a means of propulsion in the 1950s.

Germany made good use of diesel propulsion during World War I (1914–1918). Unlike Britain’s small, coastal subs, Germany’s vessels, displacing up to 3,200 tons, were capable of crossing the Atlantic Ocean. Their U-boat (short for unterseeboot) sent more than 11 million tons of Allied shipping to the bottom and, in the process, created a new, terrifying type of warfare.

In World War II (1939–1945) submarines played an even larger role in Germany’s repeated attacks on Allied shipping, eventually destroying 14 million tons of shipping. Meanwhile, American submarines crippled the Japanese by sinking nearly 1,400 merchant and naval ships. The greatest improvement came through the development of the snorkel, a set of two fixed air pipes that projected from the sub’s topside. One tube brought fresh air into the vessel, and the other vented engine exhaust fumes. Now a sub could stay hidden below the surface when running on its diesel engine and recharging its batteries.

The greatest advance in submarine technology was the advent of nuclear power. With the encouragement of United States Navy Captain Hyman Rickover, American inventors Ross Gunn and Phillip Abelson designed the U.S.S. Nautilus, the first nuclear-powered submarine. Launched in 1955, the Nautilus carried a reactor in which controlled nuclear fission provided the heat that converted water into steam for turbines. With this new power source, the submarine could remain under water indefinitely and cruise at top speed for any length of time required.

For a submarine able to remain under water for longer distances at higher speeds, a needle-like shape proved inefficient. The Davis Taylor Model Basin in the United States developed a new teardrop design, first tested on its Albacore submarine. Vessels with this improved shape easily drove through the water at speeds of 35 to 40 knots (35 to 40 nautical miles per hour). The U.S. Navy later adopted the Albacore’s shape for its submarines.

Submarines have also benefited from advances in navigation equipment. Inertial navigation systems, relying on gyroscopes, now fix their position with extreme accuracy. The U.S.S. Skate used this system to navigate under the polar ice cap at the North Pole in 1959.

In the 1990s and 2000s, submarines used for the defense of a country can launch numerous weapons such as mines, cruise missiles for land attacks, torpedoes, and submarine launched ballistic missiles (SLBMs) with nuclear warheads. Most submarines run with nuclear energy, but some still use diesel engines and electric batteries. As of the mid-2000s, the United States, Russia, the United Kingdom, China, and France are the countries with the largest and most advanced fleets of submarines. Together they operate about 150 submarines. Other countries possess smaller and less sophisticated submarines.

See also Internal combustion engine.

Submarines are special purpose naval vessels that use their submerged capability for protection. A submarine must possess a hull strong enough to withstand substantial water pressure; tanks for taking on and holding water to adjust buoyancy and facilitate diving below the water's surface; and a means of underwater propulsion. Typically, submarines carry torpedoes as weapons, but some have carried ballistic missiles.

David Bushnell's human‐powered Turtle launched the first (unsuccessful) submarine attack in New York Harbor in September 1776 during the Revolutionary War. In the Civil War, Horace Hunley built the David craft for the Confederate navy, one of which sank the USS Housatonic in July 1864, in Charleston, South Carolina, sinking itself in the process. In the late nineteenth century, John Holland, an Irish immigrant and inventor from Paterson, New Jersey, privately built a series of experimental craft culminating in a gasoline‐powered submersible, Holland VI (1896). Due to its oxygen requirements, the boat's engine could only operate while it cruised on the surface, so the vessel also had an electric battery to provide submerged propulsion. Holland's design became the basis for submarines of the U.S. Navy, and the Royal Navy bought his design as well.

European technical developments paralleled U.S. efforts, especially in Germany and France. French naval theorists of the so‐called young school (jeune école) provided submerged weapons for submarines by first combining them in 1893 with the self‐propelled torpedo. In the view of most naval officers, submarines would be especially useful to defend a coast or for a relatively weak naval power to attack an enemy line of battleships. Due to their low submerged speed, most submarines operated as temporarily submersible torpedo boats, largely sailing and often attacking while surfaced.

During World War I, the submarines, and especially the German Untersee boats (U‐boats), achieved prominence. Submarine crews gained a reputation as élite personnel who endured real hardships; few survived the sinking of a submarine. The submarines of all navies had internal combustion engines (usually diesel), a periscope, and a deck gun for surface combat, as well as torpedoes or mines. Early in the war, a submerged German U‐boat torpedoed and sank three British cruisers in one day; another was responsible for the sinking of Lusitania (1915). Against Allied merchant shipping, the long‐range U‐boat came into its own, evading the larger Royal Navy, and sometimes attacking even while surfaced until deterred by the U.S. convoy system and vigorous U.S. antisubmarine efforts in 1917–18. Allied submarines, including American boats sent to Britain in 1918, focused upon attacking enemy surface ships but faced few targets due to the enemy's caution. Since the force almost succeeded in starving Britain, the Treaty of Versailles forbade German possession of U‐boats.

After World War I, the Washington Naval Arms Limitation Conference (1922) considered a complete ban on submarines. But opposition from the Italian and French governments guaranteed that submarines remained in the inventories of most navies, and they returned in Germany after 1935. Interwar developments included improved construction, more sophisticated torpedoes, better torpedo fire control systems, and even air conditioning in U.S. vessels. Submarine doctrine remained divided between those who desired to use the boats for commerce warfare, the German goal, and those who emphasized fleet reconnaissance and attacks on warships, the policy in the U.S. and Imperial Japanese navies.

World War II saw accelerated building of submarines by both the Axis and the Allied sides, with almost 2,000 vessels serving. Overwhelmingly, submarines attacked enemy merchant shipping, despite prewar doctrines emphasizing fleet operations. Their patrols succeeded in sinking over 20 million tons of shipping, one‐quarter by 300 American boats, which provided an effective naval blockade of Japan. U.S. design innovations included improved torpedoes and the addition of radar for surface operations. Changes from 1943 onward in Germany included series construction, the snorkel, an air tube for submerged diesel use, and improvements in submarine battery power and submerged speed. All postwar diesel submarine designs made use of these German innovations.

During the Cold War, submarine design incorporated nuclear weapons and propulsion, as well as improved sonar and reduced noise signatures. Nuclear weapons entered use as torpedoes, cruise missiles, and as the strategic ballistic missiles that the United States, Soviet Union, France, Britain, and the People's Republic of China added to their fleets. Ballistic missile submarines were a prominent nuclear deterrent. Nuclear propulsion, first introduced in the U.S. Navy by Adm. Hyman Rickover, gave submarines virtually unlimited range and radically more underwater capability due to their power plants' independence of air supplies. With improved range and weapons, both diesel and nuclear submarines fully realized their capabilities, emerging as a versatile branch of modern navies.
[See also Mines, Naval; Washington Naval Arms Limitation Treaty.]

Bibliography

John Moore , Jane's Pocket Book of Submarine Development, 1976.
Ulrich Gabler , Submarine Design, 1986.
Gary Weir , Building American Submarines 1914–1940, 1991.
Gary Weir , Forged in War, 1993.
Norman Friedman , U.S. Submarines Since 1945, 1995.
Norman Friedman , U.S. Submarines Through 1945, 1995.

Sarandis Papadopoulos

SUBMARINES

SUBMARINES. The first operating submarine was tested by the Dutch inventor Cornelis Drebbel from 1620 to 1624, but a submarine was not used in combat until 1776, when David Bushnell's one-man wooden craft, the Turtle, failed in its submerged attack on the British ship Eagle in New York harbor. Later, Robert Fulton, a famous American artist and inventor, built the Nautilus (1801) out of wood covered by iron plates. Although successful in submerged tests against wooden ships, the Nautilus failed to interest the government of France, England, or the United States. Bushnell produced another submarine for the War of 1812 against England, but his craft was unsuccessful.

During the Civil War the Confederacy undertook the construction of various submarines. Horace L. Hunley financed the building of the Pioneer (1862) by James McClintock and Baxter Watson, but it never entered combat. A second vessel was lost en route to the fighting. The first submarine to sink a ship was the hand-powered Hunley. This cigar-shaped boat was made of boiler plate and manned by a crew of nine. It took the lives of thirty-five volunteers in five trial runs and became known as the Peripatetic Coffin. On the night of 17 February 1864, it drove its spar torpedo into the Union Housatonic anchored at the entrance to Charleston harbor, South Carolina, and both vessels sank. The Union's one attempt to construct a submarine proved abortive; the main effort went into semisubmersibles and monitors.

England, France, Sweden, Russia, and Spain pursued submarine development in the ninettenth century. Modern undersea craft in America evolved from the pioneering work of John P. Holland, an Irish immigrant, and Simon Lake. Holland built six submarines (1875–1897), one of which, the Plunger, won the U.S. government's competition for a practical submarine design in 1893. It was never completed. His most famous craft, the fifty-three-foot Holland, was built at his own expense and became the U.S. Navy's first submarine in 1900. Lake, Holland's chief competitor, envisioned submarines mainly as salvage and exploration vehicles. Lake's company built seven submarines for Russia (1901–1906) and twenty-seven for the United States, with the first completed in 1911.

England and Germany had a delayed interest in submarines. England's first order came in 1901; the first German vessel, the 139-foot U-1, was not completed until 1905. At the outset of World War I, there were submarines

in the fleets of all the major navies. The standard submarine was about two hundred feet long and displaced several hundred tons. German U-boats sank more than five thousand merchant and fishing ships during the conflict. After the war, the U.S. Navy built a series of classes leading to the successful Gato and Balao classes of sub-marine of World War II.

Germany again used submarines to good advantage during World War II, although its attacks failed in the end because of a devastating Allied antisubmarine campaign. In the Pacific, U.S. submarines sank 1,314 naval and merchant ships (1941–1945). Two wartime developments—radar and the snorkel (breathing tubes to draw in air from just under the surface)—made a major impact on submarine combat.

After World War II, the United States was quick to adapt advanced German submarine technology. War-built submarines were converted to the improved GUPPY-configuration (1946–1962), and the world's first nuclear-powered submarine, the U.S.S. Nautilus, was launched in 1954. With a three-thousand-ton displacement and 320 feet long, the Nautilus traversed the Arctic Ocean under the ice cap, crossing the North Pole on 3 August 1958. The U.S. Navy married the advanced Albacore "tear drop" hull with a nuclear propulsion plant to produce the Skipjack (1956–1957), and later the Thresher, Sturgeon, and Los Angeles, classes of very fast submarines, capable of underwater speeds exceeding thirty knots.

The majority of U.S. nuclear submarines are primarily intended to destroy enemy submarines; the remainder are the fleet ballistic-missile submarines armed with strategic Polaris, Poseidon, or Trident missiles for use against land targets. The Navy commissioned forty-one Polaris-Poseidon submarines between 1959 and 1967. Displacing between 5,900 and 7,320 tons each, these vessels were a vital part of the U.S. nuclear deterrent force.

The submarine played a vital role in America's Cold War military strategy. Beginning with the Poseidon missile (1970), all U.S. submarines carried submarine launched ballistic missiles (SLBMs), all of which carried multiple warheads, dubbed multiple independently targeted reentry vehicles (MIRVs). The Trident carries twenty-four Trident C-4 or D-5 missiles, each loaded with eight warheads. In 1988, the United States had sixty-six hundred warheads on thirty-two submarines and the Soviet Union thirty-four hundred warheads on sixty-three submarines. Both forces were reduced under the terms of the first Strategic Arms Reduction Talks Treaty (START I). The START II agreement in 1993 downgraded the U.S. force to about seventeen hundred warheads on eighteen submarines. The accuracy of SLBMs was greatly improved with the introduction of the global positioning system (GPS). Signals emitted from satellites in orbit enable the missile's computers to calculate its position with very high precision.

BIBLIOGRAPHY

Alden, John D. The Fleet Submarine in the U.S. Navy: A Design and Construction History. Annapolis, Md.: Naval Institute Press, 1979.

Burgess, Robert F. Ships Beneath the Sea: A History of Subs and Submersibles. New York: McGraw-Hill, 1975.

Cochran, Thomas B., William M. Arkin, and Milton M. Hoenig. Nuclear Weapons Databook. Vol. 1. Cambridge, Mass.: Ballinger, 1984.

———, et al. Nuclear Weapons Databook. Vol. 4. New York: Harper and Row, Ballinger Division, 1989.

Hoyt, Edwin P. From the Turtle to the Nautilus: The Story of Submarines. Boston: Little, Brown, 1963.

Polmar, Norman. The American Submarine. Annapolis, Md.: Nautical and Aviation Publishing Company of America, 1981

———, and Jurrien Noot. Submarines of the Russian and Soviet Navies, 1718–1990. Annapolis, Md.: Naval Institute Press, 1991.

Roscoe, Theodore. United States Submarine Operations in World War II. Annapolis, Md.: United States Naval Institute, 1949.

LeoSartori

Ken W.Sayers/a. r.

See alsoAtlantic, Battle of the ; Lusitania, Sinking of the ; Merchantmen, Armed ; Missiles, Military ; "Nautilus" ; Navy, Confederate ; North Sea Mine Barrage ; Philippine Sea, Battle of the ; World War II, Navy in .

Submarine

The first known treatise on submarines was written in 1578. Published by William Bourne in his Inventions or Devices, the document describes a ship with two hulls, the outer made of wood . While no record exists concerning its manufacture, the ship, according to Bourne, could be submerged or raised by taking in or expelling water from between the double hulls. The first known submarine was built by Dutch inventor Cornelius Drebbel, and consisted of greased leather over a wooden framework. It was propelled either on or beneath the surface by eight oars sealed through the sides with leather flaps. During a demonstration for James I in 1620, this vessel was successfully piloted just under the surface of the Thames River. It was unable, however, to make deep descents.

During the American Revolution, David Bushnell built a one-man submarine called the Turtle. It resembled an egg squashed thin with a height of 6 ft (2 m), and had two hand-cranked screw propellers, a hand-operated control lever connected to the rudder, foot-operated pumps to let water in or send it out (to submerge or surface), and a crudely-lit control panel. As if it was not dangerous enough simply to get in the water sealed inside this device, the Turtle also had a large explosive attached to it in the hopes the operator could maneuver under an enemy ship, screw the explosive into the ship's hull, and depart before the explosive's timing device discharged it. Unfortunately, the Turtle failed to sink any ship. On its only test mission, the Turtle was assigned the task of bombing the British HMS Eagle in New York, but its pilot was unable to screw the explosive into the Eagle's copper hull.

Others, such as English carpenters Symons and Day, included ballast systems on their submarines to permit descents. Day's submarine resembled a sloop, and had two large bags of stones hanging from its bottom to serve as ballast. Day would sink, then jettison the rocks to return to the surface. After two successful tests, Day confidently decided he would test his vessel off Plymouth Sound, a site with a depth of 900 ft (274 m). Apparently his ship was crushed by high water pressure , for when he and his crew descended, a crowd of onlookers waited in vain for his return. Day and his crew had become the first victims of a submarine mishap.

Perhaps the most successful early submarine was designed by Robert Fulton. In an age of naval battles, Fulton, who detested war, felt that a device capable of neutralizing the effectiveness of warships would end war altogether. While living in France in 1767, he outlined plans to build a sub called the Nautilus and unsuccessfully attempted to interest the French government in his idea. By 1801, however, he had managed to complete a submarine on his own. A 21 ft (6 m) vessel with a twobladed propeller, the Nautilus performed well in tests, even sinking a ship with an explosive charge. But he was once again rejected by the French government, so he moved to England, hoping for a better reception there.

It soon became clear that the English did not want his submarine either. In fact, Fulton had failed not because his vessel did not work, but because major naval powers feared his vessel and did not want to participate in developing a weapon that could negate their military strength. Fulton went on to produce his famous steamboats in the United States.

After the American Civil War, designers, spurred on by the invention of the self-propelled torpedo in 1866, increasingly sought alternatives to human-powered propulsion for submarines. Several systems proved unsuitable—steam engines made the craft unbearably hot and an electric battery could not be recharged at sea. In the late 1890s, however, Irish-born American John Holland solved the problem with the use of a new power source, the gasoline engine. Because it needed oxygen , the gasoline engine could not be used while a submarine was underwater, but on the surface it could not only provide propulsion but also charge the batteries used while submerged. Holland's vessels incorporated many of the features we associate with modern subs: a powerful engine, advanced control and balancing systems, and a circular-shaped hull to withstand pressure. The United States Navy accepted his submarine, the Holland, in 1900.

Around this time, two other improvements were introduced. Simon Lake (1866-1945), who also built an early gasoline-powered submarine, created the first periscope specifically for submarines: it provided a magnified view and a wide angle of vision . In the 1890s Rudolf Diesel invented an engine that was fired by compression rather than an electric spark. The diesel engine was more economical than the gasoline engine and its fumes were much less toxic and volatile. This new engine became the mainstay of all submarines until nuclear power was introduced as a means of propulsion in the 1950s.

Germany made good use of diesel propulsion. Unlike Britain's small, coastal subs, Germany's vessels, displacing up to 3,200 tons, were capable of crossing the Atlantic. Their U-boat (short for unterseeboot) sent more than 11 million tons of Allied shipping to the bottom and, in the process, created a new, terrifying type of warfare.

In World War II submarines played an even larger role in Germany's repeated attacks on Allied shipping, eventually destroying 14 million tons of shipping. Meanwhile, American submarines crippled the Japanese by sinking nearly 1,400 merchant and naval ships. The greatest improvement came through the development of the snorkel, a set of two fixed air pipes that projected from the sub's topside. One tube brought fresh air into the vessel, and the other vented engine exhaust fumes. Now a sub could stay hidden below the surface when running on its diesel engine and recharging its batteries.

The greatest advance in submarine technology was the advent of nuclear power. With the encouragement of United States Navy Captain Hyman Rickover, American inventors Ross Gunn and Phillip Abelson designed the U.S.S. Nautilus, the first nuclear-powered submarine. Launched in 1955, the Nautilus carried a reactor in which controlled nuclear fission provided the heat that converted water into steam for turbines. With this new power source, the submarine could remain under water indefinitely and cruise at top speed for any length of time required.

For a submarine able to remain under water for longer distances at higher speeds, a needle-like shape proved inefficient. The Davis Taylor Model Basin in the United States developed a new teardrop design, first tested on its Albacore submarine. Vessels with this improved shape easily drove through the water at speeds of 35-40 knots per hour. The United States Navy later adopted the Albacore's shape for its submarines.

Submarines have also benefited from advances in navigation equipment. Inertial navigation systems, relying on gyroscopes, now fix their position with extreme accuracy. The U.S.S. Skate used this system to navigate under the polar ice cap at the North Pole in 1959.

See also Internal combustion engine.

Submarine

A submarine is a ship capable of operating underwater. Because its great advantage is its ability to stay hidden, the submarine has developed as a tool of warfare.

In 1578, in his book Inventions or Devices, William Bourne described a ship with two hulls (bodies), one made of wood, the other of leather. According to Bourne, the ship could be submerged or raised by taking in or expelling water from between the double hulls.

The first known submarine to be built was by Dutch inventor Cornelius Drebbel. It consisted of greased leather over a wooden framework. It was propelled either on or beneath the surface by eight oars sealed through the sides with leather flaps. During a demonstration for English king James I in 1620, Drebbel's vessel was successfully piloted just under the surface of the Thames River in London. However, it did not make deep descents.

During the American Revolution (1776–81), American inventor David Bushnell built a one-man submarine called the Turtle. It was 6 feet (2 meters) tall and resembled a slightly squashed egg. It had two hand-cranked screw propellers, a hand-operated control lever connected to the rudder, foot-operated pumps to let water in or send it out (to submerge or surface), and a control panel. The Turtle also had a large explosive attached to it in the hopes the operator could maneuver under an enemy ship, screw the explosive into the ship's hull, and depart before the explosive's timing device discharged it. On its only test mission, the Turtle failed to sink its target.

Robert Fulton

Perhaps the most successful early submarine was designed by American inventor Robert Fulton. He lived in an age of naval battles, but hated war. Fulton hoped that a device that could make warships ineffective would end war altogether. In 1801, he built a 21-foot (6-meter) vessel with a two-bladed propeller, which he called Nautilus. After he was unable to interest both the French and English governments in his idea, Fulton abandoned the submarine project, returned home, and went on to produce his famous steamboats in the United States.

After the American Civil War (1861–65), designers sought alternatives to human-powered propulsion for submarines. Several systems proved unsuitable; for instance, steam engines made the craft unbearably hot and an electric battery could not be recharged at sea.

In the late 1890s, Irish-born American John Holland solved these problems by adding a second power source, the gasoline engine, to the batteries then in use. Because it needed oxygen, the gasoline engine could not be used while a submarine was underwater. When the ship was above water, its engine could provide propulsion and charge the batteries used while the ship had been submerged. Holland's vessels incorporated many of the features found in modern submarines: a powerful engine, advanced control and balancing systems, and a circular-shaped hull to withstand pressure. The United States Navy accepted his submarine, the U.S.S. Holland, in 1900.

Periscopes and diesel engines

Around this time, two other improvements were introduced. Inventor Simon Lake created the first periscope specifically for submarines. A periscope is a vertical telescope that provides a magnified view and a wide angle of vision. In the 1890s, Rudolf Diesel invented an engine that was fired by compression rather than an electric spark. The diesel engine was more economical than the gasoline engine and its fumes were much less toxic (poisonous) and volatile (explosive). This new engine became essential to all submarines until nuclear power was introduced as a means of propulsion in the 1950s.

In World War II (1939–45), submarines played a large role in Germany's repeated attacks on Allied (English, American, and French) ships. Meanwhile, American submarines crippled the Japanese by sinking nearly 1,400 merchant and naval ships. During this time, the snorkel was developed. It was a set of two fixed air pipes that projected from the sub's topside. One tube brought fresh air into the vessel, and the other vented engine exhaust fumes. Now a sub could stay hidden below the surface when running on its diesel engine and recharging its batteries.

Nuclear power

The greatest modern advance in submarine technology was the introduction of nuclear power. With the encouragement of U.S. Navy captain Hyman Rickover, American inventors designed the U.S.S. Nautilus, the first nuclear-powered submarine. Launched in 1955, the U.S.S. Nautilus carried a reactor in which controlled nuclear fission provided the heat that converted water into steam for turbines. With this new power source, the submarine could remain underwater indefinitely and cruise at top speed for any length of time required.

However, the traditional needle-like shape proved inefficient for such a submarine. A new teardrop design was introduced in the United States. Vessels with this improved shape easily drove through the water at speeds of 35 to 40 knots (about 40 to 46 miles or 64 to 74 kilometers) per hour. The U.S. Navy later adopted this shape for its submarines.

[See also Diesel engine; Nuclear power ]