David Bushnell (inventor)

David Bushnell (1740 to 1824) was an American inventor, teacher and medical doctor, and a veteran of the American Revolutionary War. He is remembered in transport and naval history as the designer of Turtle, a hand powered, egg shaped submersible vessel intended to attach an explosive charge to the hull of a British warship, making it the first submarine recorded to have been used in a military attack when it was deployed against HMS Eagle in New York harbor in 1776. Although the attack failed to sink its target, Turtle demonstrated the basic working principles of underwater ballast control, hand cranked propulsion and a detachable explosive charge that later submarine designers would build on. Bushnell also invented a floating naval mine that could be triggered by contact, another innovation aimed at attacking enemy shipping during the war. After the war he continued his career as an inventor and later practiced medicine under an assumed name in Georgia, but his wartime work on Turtle remains his defining contribution to the early history of underwater transport and naval warfare.