Turtle was the hand-powered submarine used in an American Revolutionary War attack attempt.
David Bushnell designed Turtle in 1775, and the small, one-person craft was built by his brother Ezra. Its operator turned a hand crank to drive propellers, while separate controls helped the vessel move vertically and horizontally. The design used ballast tanks and a screw-like mechanism to approach enemy ships underwater.
In September 1776, Sergeant Ezra Lee reportedly piloted Turtle toward HMS Eagle in New York Harbor. He attempted to attach an explosive charge beneath the British ship, but the drill could not penetrate the ship’s copper sheathing. The charge was released nearby and exploded without sinking Eagle.
Turtle therefore did not achieve its intended result, but it is widely recognized as the first submarine used in an attempt to attack an enemy vessel. It was also an early example of a purpose-built military submarine, rather than a diving bell or underwater observation device.