Turtle (submarine)
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Turtle was the world's first submarine used in battle. It was invented in Connecticut in 1775 by David Bushnell and was created as a means of attaching explosive charges to ships in a harbor.
Named for its shape, Turtle resembled a large clam as much as a turtle; it was 7.5 feet (2.3 m) long, 6 feet (1.8 m) tall, and about 3 feet (0.9 m) wide, consisting of two wooden shells covered with tar. It submerged by allowing water into the hull and ascended by pushing water out through a hand pump, similarly to the use of ballast tanks in modern submarines, and was propelled vertically and horizontally by hand-cranked propellers, the first recorded use of the screw propeller for ships. It was manned and operated by only one person.
The submarine was designed as a naval weapon, and it was meant to drill into a ship's hull and plant a keg of powder, which would be detonated by a time fuse. Much testing was done by the inventor's brother, Ezra Bushnell, in the waters of the Connecticut River. After Bushnell pondered the problem of lighting the inside of the ship and after learning that using a candle would hasten the use of the limited oxygen supply of the air inside, he solicited the help of Benjamin Franklin who cleverly hit upon the idea of using bioluminescent foxfire to provide illumination for the compass and depth meter. The light given by the material was said to be sufficient, though likely dimmer than expected, because the ship was cooled by the surrounding sea water and the metabolic rate of poikilothermic, heterotrophic organisms is temperature-dependent.
On September 7, 1776, Turtle, under the guidance of Army volunteer Sergeant Ezra Lee, attacked HMS Eagle, which was moored off what is today called Liberty Island, but it could not manage to bore through the hull. When he attempted another spot in the hull, he lost the ship, and eventually abandoned the attempt.
In 1976, a recreation was designed by Joseph Leary and constructed by Fred Frese as a Bicentennial project. It was christened by Connecticut's governor, Ella Grasso, and later tested in the Connecticut River. It is owned by the Connecticut River Museum and is currently on loan to Old Saybrook High School in Old Saybrook, Connecticut, where students under the direction of Fred Frese are currently building a working recreation of that model.
[edit] References
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- Alex Roland, Underwater Warfare in the Age of Sail (Indiana University Press, 1978), chaps. 5 and 6 ISBN 0-253-31824-6
