Bushnell's Turtle was a war submarine built in 1776 by David Bushnell.
It was a wooden oval banded with iron rings, 11 feet high and 7 feet across, driven by two hand-cranked propellers; the rudder was operated by a foot pedal. A metal screw protruded from it, ready to drill into the hull of an enemy ship and deposit a clockwork gunpowder torpedo.
Lighting the Turtle was a problem; burning a candle used too much oxygen in the cramped interior of the sub. The solution, suggested by Benjamin Franklin, was to line the sub's walls with foxfire, which is wood that is rotten with a phosporescent fungus.
Lead ballast, and water ballast in a chamber with a pump and a valve, controlled the depth of the sub's descent. In the submerged vessel, there was air for one person for 30 minutes.
General George Washington and Connecticut Governer Jonathan Trumbull funded the building of Bushnell's Turtle.
It was first used against HMS Eagle, the flagship of the British Admiral Howe, in New York Harbor. The Turtle maneuvered, undetected, into place and began to drill. But the torpedo did not attach successfully. In its second attempt, the Turtle was foiled by a metal plate in the Eagle's hull. Though the Turtle didn't blow up its targets, the British fleet may have been scared out of New York Harbor by it.
The pilot in this attempt, Ezra Lee, was barely trained to use the sub, and had rowed it for over an hour underwater in treacherous tidal currents.
Subsequent attempts to blow up British vessels also failed.
The submarine was actually christened as the American Turtle, but history has called it after its inventor. Bushnell abandoned the idea of building a new submarine when the Turtle, when in transport aboard anAmerican ship, was sunk in October 1776.