David Bushnell (1740–1824), of Westbrook, Connecticut, was an American inventor and a veteran of the Revolutionary War. He is credited with creating the first submarine ever used in combat, while studying at Yale College in 1775. He called it the Turtle because of its look in the water. His idea of using water as ballast for submerging and raising his submarine is still in use, as is the screw propeller, which was used in the Turtle.
While at Yale, Bushnell proved that gunpowder could be exploded under water. He also made the first time bomb. He combined these ideas by building the Turtle which was designed to attack ships by attaching a time bomb to their hulls, while using a hand powered drill and ship auger bit to penetrate the hulls. He used the Turtle in attempts to attack British ships which were blockading New York Harbor in the summer of 1776. His efforts failed every time because the Turtle's boring device was unable to penetrate the copper sheeting lining in the ships' hulls which was designed to protect against parasites in their previous destination, the Caribbean. The Turtle was lost while being transported aboard a sloop; the sloop was discovered, and sank, by British frigates leaving Bloomingdale.
In 1777 Bushnell attempted to use a floating mine to blow up the HMS Cerberus (1758) in Niantic Bay; the mine struck a small boat near the Cerberus and detonated killing four sailors  and destroying the vessel, but not the intended target. In 1778 he launched what became lauded as the Battle of the Kegs, in which a series of mines was floated down the Delaware River to attack British ships anchored there, killing two curious young boys  and alerting the British. The attack was ineffectual. In 1778, General Washington proposed the formation of a new military unit to be known as the "Corps of Sappers and Miners" and in the summer of the next year it was organized. Bushnell was given command of the Corps with the rank of captain-lieutenant on August 2, 1779. On 6 May 1779, he was taken prisoner in Middlesex Parish, now Darien, Connecticut.
On 8 June 1781, David Bushnell was commissioned as a captain in the Continental Army and was at the Siege of Yorktown in the following September and October. This was the only time the unit had had the opportunity to serve in combat.
Bushnell served in the Army until he was discharged on June 3, 1783. He then became an original member of the Connecticut Society of the Cincinnati, an organization formed by officers who were veterans of the Continental Army and Navy.
At some point after the Revolution, Bushnell was presented a medal by George Washington.
After peace was declared he returned to Connecticut then later traveled to France and then settled in Warrenton, Georgia where he taught at the Warrenton Academy and practiced medicine. He died in Georgia in 1824.
In 1915, the U.S. Navy named the submarine tender USS Bushnell (AS-2) after him and it was launched in Bremerton, Washington. On 14 September 1942, another submarine tender of the same name USS Bushnell (AS-15) was launched.
- Charles Griswold to Professor Silliman, Lyme CT, 21 Feb 1820; from "The Beginning of Modern Submarine Warfare, under Captain-Lieutenant David Bushnell, Sappers and Miners, Army of the Revolution;" Henry L. Abbot (pamphlet, 1881); reproduced by Frank Anderson (Archon Books and Shoe String Press, Hamden CT, 1966); pp 26-28
- Swanson, June. David Bushnell and His Turtle" - The Story of America's First Submarine. Atheneum. 1991. ISBN 0-689-31628-3
- The Record of Connecticut Men in the Military and Naval Service During the American Revolution, by the Connecticut Historical Society
- Lefkowitz, Arthur S. "Bushnell's Submarine" - The Best Kept Secret of the American Revolution. Scholastic Inc. 2006. ISBN 0-439-74352-4