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PropulsionSubmarines Nuclear Propulsion | Jet Propulsion, Electric propulsion | Power Submarines |
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Propulsion | Submarines Nuclear Propulsion | Jet Propulsion, Electric propulsion | Power SubmarinesPropulsion | Submarines Nuclear Propulsion | Jet Propulsion, Electric propulsion | Power Submarines Modern submarines use either diesel-electric or nuclear power to drive the sub's propeller and to provide internal electric power. Diesel-electric power emerged as the most efficient propulsion system for submarines in the early 20th century, following unsuccessful attempts to use steam or gasoline power. While on the surface, the submarine uses a diesel engine to drive the propeller and generate electricity. When submerged, a battery-driven electrical motor takes over for propulsion and power. The diesel engine recharges the batteries. Using the diesel engine requires air, however, and so a submarine has to surface and thus expose itself to attack. German engineers solved this problem in the design of their World War II submarines, called U-boats. They did so by developing the snorkel, a retractable tube that can be extended above the surface of the water while the submarine operates at periscope depth—about 18 m (60 ft) below the surface. The snorkel provided the air to burn fuel in the diesel engine and vented off the exhaust fumes produced by the engine. Using the snorkel gave a margin of safety for submarines as they recharged their batteries, and allowed submarines to extend their underwater range considerably. Propulsion | Submarines Nuclear Propulsion | Jet Propulsion, Electric propulsion | Power Submarines The successful design in the early 1950s of a nuclear reactor small enough to fit inside a submarine hull was the most significant advance in submarine technology since the advent of diesel-electric propulsion a half-century earlier. A U.S. Navy team led by then-Captain Hyman G. Rickover engineered the breakthrough. Their success followed years of scientific speculation that a controlled nuclear fission reaction might be harnessed to power submarines. The theory is as simple as the reactor designs are complex: A controlled nuclear reaction, which takes place within a pressure vessel, produces enormous heat energy. This heat is channeled through a piping system that, in turn, heats water in a second, separate circuit of pipes. The heated water turns to steam, which passes through a turbine to power the submarine's propulsion drive. The steam also provides internal electric power via a turbine-driven generator. Because the nuclear reactor does not need access to fresh air, a modern nuclear submarine can cruise submerged for an unlimited amount of time. During long stretches underwater, the vessel replenishes its supply of breathing oxygen through hydrolysis, a chemical process that extracts oxygen from seawater. Propulsion | Submarines Nuclear Propulsion | Jet Propulsion, Electric propulsion | Power Submarines |
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Propulsion | Submarines Nuclear Propulsion | Jet Propulsion, Electric propulsion | Power Submarines |
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