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Nedeľa, 19. mája 2024
Early History - Submarines
Dátum pridania: 30.11.2002 Oznámkuj: 12345
Autor referátu: mondeo
Jazyk: Angličtina Počet slov: 355
Referát vhodný pre: Stredná odborná škola Počet A4: 1.2
Priemerná známka: 2.99 Rýchle čítanie: 2m 0s
Pomalé čítanie: 3m 0s
Early History - Submarines

The first successful underwater craft was a leather-encased wooden rowing boat, built in England in the 1620s by the Dutch inventor Cornelis Drebbel. The vessel carried 12 oarsmen and several passengers below the surface of the Thames in a series of trips lasting several hours. Drebbel reputedly used air tubes 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, which carried only one crew member. Called Bushnell's turtle, it was invented in the 1770s by an American engineer, David Bushnell. This craft was propelled by hand-operated screw-like devices; it submerged when a valve admitted sea water into a ballast tank and rose when the tank was emptied by a hand pump. Lead ballast kept the boat upright. Because it lacked an underwater supply of oxygen, the boat could remain submerged for only half an hour. During the American War of Independence it was used in an unsuccessful attack on a British ship anchored in New York Harbor.

In 1800 the American inventor Robert Fulton built a 6.4-m (21-ft) submarine, the Nautilus, which was similar in shape to the modern submarine and included two important innovations: 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 vessels were built during the American Civil War by Confederate forces for use against the Union fleet.

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, developed by the American inventor John Philip Holland, was powered by a dual-propulsion system. Launched in 1898, the submarine, which had an overall length of 16.2 m (53 ft), was equipped with a petrol-driven engine for surface cruising and an electric motor for underwater power.
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