Bushnell, David

Bushnell, David (c.1742–1824), American inventor, one of the fathers of the submarine. Graduating from Yale in 1775, the year of the first skirmish between British troops in America and the colonists, he had bitter feelings against Britain and determined to put his engineering abilities to use in aid of the American colonies in revolt. He designed and built a small wooden ‘submarine’ named USS Turtle. It was shaped like an egg, floated upright in the water, and could be trimmed down until the conning tower was awash by admitting water to two small internal tanks. This curious vessel carried a detachable charge of 68 kilograms (150 lb) of gunpowder which could be fixed to the bottom of an enemy ship by means of a screw. In 1776, when the British fleet was lying off New York, Bushnell launched his submarine with a sergeant in the American Army, Ezra Lee, operating it by turning a propeller by hand. Lee managed to force it under the hull of HMS Eagle, flying the flag of Lord Howe (1726–99), but was unable to screw the charge home as Bushnell had not made allowance for the fact that the bottoms of British warships at that time had copper sheathing. At the end of the war in 1782, Bushnell gave up his submarine experiments and, assuming another name, became a successful doctor.