Oil Painting of the "Turtle", the United States' First Submersible, 1777

The Turtle, built in 1775 by American inventor David Bushnell, was the first military submarine used in combat. Made of oak and shaped like two turtle shells joined together, it was designed for a single operator who used hand-cranked propellers and a ballast system to maneuver underwater. Its mission was to attach timed explosives to British ships during the Revolutionary War. In September 1776, Sergeant Ezra Lee piloted the Turtle against HMS Eagle in New York Harbor, but the attack failed when he could not drill into the ship’s copper hull. Though it never scored a victory, the Turtle pioneered submarine warfare and showcased American ingenuity in the struggle for independence.