Turtle was the world's first submarine used in battle. It was invented in Connecticut in 1775 by American Patriot David Bushnell as a means of attaching explosive charges to ships in a harbor. The submarine was designed as a naval weapon, and it was meant to drill into a ship's hull and plant a keg containing 130 pounds of gunpowder, which would be detonated by a time fuse.
Named for its shape,it was about 8 feet long (according to original specs), 6 feet (1.8 m) tall, and about 3 feet (0.9 m) wide, consisting of two wooden shells covered with tar and reinforced with steel bands.
It submerged by allowing water into a bilge tank at the bottom of the vessel and ascended by pushing water out through a hand pump and was propelled vertically and horizontally by hand-cranked propellers. It also had two hundred pounds of lead which could be released in a moment to increase buoyancy. It was manned and operated by one person. It contained enough air for about thirty minutes and had a speed in calm water of about three miles per hour.
It was reputed to have attempted an attack on Admiral Howe's flagship HMS Eagle on the night of September 7, 1776. Though problems with strong currents and in keeping the submarine in a stable enough position to attach the explosive proved overwhelming and the attack had to be abandoned.