The first truly successful underwater boat was a small, leather-encased wooden craft, built in England in 1620 by the Dutch inventor Cornelis Drebbel. The vessel carried 12 oarsmen and several passengers below the Thames River in England in a series of trips lasting hours. Drebbel used air tubes supported on the surface of the water by floats to provide air while the boat was underwater. The first military sub was an egg-shaped craft, which carried one crew member; called the Turtle, it was invented in the 1770s by an American engineer named David Bushnell. The Turtle was pushed along by hand-operated propellors, submerged when a valve admitted seawater into a ballast tank, and rose when the tank was emptied by a hand pump. Lead ballast kept the boat upright. It was not a great success, as it never sank one target it was supposed to. Air supply was a problem; it had none, and had to be brought up every 30 minutes. In 1800 the American inventor Robert Fulton built a 21 foot-long submarine named the Nautilus, which was similar in shape to the modern submarine. There were two important improvents over the Turtle: rudders for vertical and horizontal control and compressed air as an underwater supply. It used a hand-cranked, four-blade propeller. On the surface the boat was propelled by sails. Four primitive subs were built during the American Civil War by the Confederates. In 1864 a Confederate submarine, the Hunley, blew up the USS Housatonic in Charleston, South Carolina, Harbor, but was itself destroyed by the explosion. Not exactly a quantum leap, but some progress was being made. From 1870-to 1900 many attempts were made to develop reliable submarine propulsion. Inventors experimented with compressed air, steam, and electricity. The first practical submarine with a realistic power plant was created by the American inventor John Philip Holland. Launched in 1898, The USS Holland had a gasoline engine for surface cruising and an electric motor for underwater. It had an overall length of 16.2 m (53 ft). This was probably the first completely practical craft. An American engineer named (likely enough) Simon Lake did a great deal towards perfecting the submarine. In 1898 he came up with the free-flooding superstructure. In 1906 the Germans applied the diesel to the submarine, an important development. Then came the periscope and the self-propelled torpedo, and the submarine became a factor in naval warfare to be reckoned with. During WWI, German submarines, known as U-boats, sank tons of allied shipping. Depth charges were invented during this period as countermeasures. During 1918-1945 the sub came into it's own. Sonar and rescue devices, such as the lightweight breathing apparatus became standard equipment for crews in case of emergency. A typical Allied World War II submarine had a surface speed of about 18 knots using diesel engines and a submerged speed of 8 knots using electric motors. But operating range was limited with batteries, and the subs had to surface to recharge. The Germans, however, were not limited by this, having a device called "The Snorkel", which the allies did not; this allowed them to perform a recharge at periscope depth. A new blimp-like sub shape came in with the USS Albacore, launched in 1953. It was extremely successful. All subs that came after took this shape. The first nuclear-powered submarine was launched in 1954. Early in August 1958 the Nautilus made the first undersea transit of the North Pole, cruising under the polar ice pack from Point Barrow, Alaska, to a point between Spitsbergen, Norway. The Seawolf was launched shortly thereafter and set an endurance record for underwater operation of two months. In the early 1970s the U.S. started the development of the Trident I system, a successor to the earlier Polaris-Poseidon. Currently it is estimated that the U.S. has 132 submarines in operation, almost all of them nuclear-powered. © 1997-2017 by Moonlight Systems All rights Reserved (Click here for Copyright info)