The idea of using a modified screw to propel a ship had been proposed as early as 1752. John Fitch experimented with a screw propeller before his steam paddle boat. Both the Bushnell (1777) and Fulton (1797) submarines used propellers. Of course a paddlewheel would not make sense for an underwater boat, so propellers were mandatory on submarines.
Several experiments were made with different versions of a screw propeller. These assumed that a ship could be propelled not by sail, oars, or paddlewheels, but by a modified version of the Archimedes screw. One preferred design included a long tube enclosing a screw shape, like the historical water lifting device called the Archimedes Screw. Some did away with the tube, and just had a long screw. In 1834 Britain Francis Pettit Smith built one such long wooden screw to drive his 237 ton ship Archimedes. In trials part of the long screw broke off, and to everyone's surprise, instead of slowing the ship down, the shorter screw speeded it up. More experiments arrived at a very short screw shape, closer to what we know as a propeller.
The original propeller of the Archimedes was mounted about in the center of the hull, and was really a screw, not a bladed propeller that later was developed. First tested in 1839, the Archimedes hoped to achieve 4-5 knots, but the engineering world was astounded when it achieved 9.5 knots. However, the engineering world was skeptical, and many were adamently opposed not only to screw propellers, but also iron ships and steam power. The Rattler was built for the British Navy in 1841.
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Posted by: TheRealNeo | April 11, 2006 at 10:34 AM