Alex Hubbard age 12, of Lake Charles, La., for his question:
WHO BUILT THE FIRST SUBMARINE?
A submarine is a naval vessel designed principally for underwater operations. The first successful underwater craft was a leather encased wooden rowboat that was built in England in the late 1620s by a Dutch inventor named Cornelius Drebbel.
According to accounts, Drebbel's vessel carried 12 oarsmen and several passengers below the surface of the Thames River in a series of trips that lasted several hours. Accounts also say the inventor used air tubs supported on the surface of the water by floats to replenish the oxygen supply while the boat was underwater.
The first submarine to be used as an instrument of war was an egg shaped craft called the Turtle. It was invented in the 1770s by an American engineer named David Bushnell. It was propelled by hand operated screwlike devices. It submerged when a valve admitted seawater into a ballast tank and it rose when the tank was emptied by a hand pump.
Lead ballast kept Bushnell's submarine upright. But because it lacked an underwater supply of oxygen, the Turtle could remain submerged for only a half hour. During the American Revolution it was used in an unsuccessful attack on a British ship anchored in New York Harbor.
In 1800, an American inventor named Robert Fulton built a submarine named the Nautilus which was similar in shape to the modern submarine. Fulton introduced two important features in his new craft: rudders for vertical and horizontal control and compressed air as an underwater supply of oxygen.
When submerged, the Nautilus was powered by a hand operated, four blade propeller. On the surface the boat was propelled by means of sails attached to a folding mast.
Four submersible vessles were built during the American Civil War by the Confederates for use against the federal fleet. In 1864, a Confederate submarine, the Huntley, blew up the U.S.S. Housatonic in Charleston, S.C. Harbor, but was itself destroyed by the explosion.
In the latter half of the 19th century many attempts were made to develop an adequate means of submarine propulsion. Inventors experimented with compressed air, steam and electricity as power sources.
The first practical submarine with an efficient source of power was developed by an American inventor named John Philip Holland who used a dual propulsion system. Launched in 1898, Holland's submarine was equipped with a gasoline engine for surface cruising and with an electric motor for underwater power. The boat, which had an overall length of 53 feet, was purchased by the U.S. government in 1900 and named the U.S.S. Holland.
An American engineer named Simon Lake made several contributions to the development of the modern submarine, notably by designing in 1898 the free floating superstructure.
In 1906 the Germans adapted the diesel engine to the submarine. They also came up with the periscope and the self propelled torpedo.
The effectiveness of the underwater craft as a deadly weapon was first demonstrated during World War I when German submarines, known as U boats, were used extensively against Allied warships and merchant vessels.