In the early morning hours of September 7, 1776, General Washington ordered a secret attack on Lord Admiral Howe’s British ship, the HMS Eagle, anchored near New York Harbor. The attack was to be made by a secret weapon called the Turtle. To a creative 21st century mind, visions of a Teenage Mutant Ninja Turtle (my favorite Leonardo) hopping aboard Howe’s ship with his swords whirling come to mind. This, however, was not the Turtle of Washington’s day. Washington’s Turtle was the first submersible weapon ever used in war.
The Turtle was designed by a young Yale graduate by the name of David Bushnell. Bushnell was only 21-years-old when he began experimenting with detonating gun powder under water. Bushnell took this idea and envisioned a submersible vessel with the ability to deliver a timed explosive charge next to a ship’s hull, causing massive damage, and sinking the ship. While we take this torpedo technology for granted today, Bushnell’s idea was revolutionary and nearly one-hundred years ahead of his time.
The Turtle’s design was an engineering marvel. At 7 feet long, 6 feet high, and 3 feet wide, the Turtle was just large enough for a man to fit inside. It was made from two large halves of an oak tree. The huge oak slabs were hollowed out, and then joined together with tongue and groove construction. With a generous application of oakum sealant (hemp, jute, and tar), the Turtle was nearly watertight. Bushnell also designed a propeller, which he called an oar, that was manually turned by the operator using a spinning wheel type foot pedal. A tiller was mounted for steering and a ballast tank was added to allow the Turtle to travel underwater. To surface, the operator would need to manually pump out the water in the ballast tank. Glass mounted at the top of the vessel allowed the operator to maneuver.
While the Turtle’s design was a marvel, it had a significant limitation. It relied solely on human power to move. This problem was compounded by the fact that there would be a limited supply of oxygen contained inside the Turtle once under water. Pedaling the Turtle out into the tides and currents of New York Harbor would be a difficult and dangerous task. This danger is exactly what the Turtle’s operator, Ezra Lee, volunteered for as he began his journey on September 7, 1776.
Ezra was to pilot the Turtle under the HMS Eagle’s hull and then attach an underwater timed explosive to the ship. Ezra would need to use an auger drill fastened to the top of the Turtle to drill a hole to attach the explosive to the Eagle. Ezra took nearly two hours to reach the Eagle, and once there was exhausted and likely suffering from oxygen deprivation. He could not get the auger to drill into the Eagle’s hull. British ships had a metal plate connected to the rudder hinge, which may have prevented Ezra’s drill from working. Ezra’s failure may have also been due to his fatigue and inability to think clearly form a lack of oxygen. With dawn fast approaching and fear that he would be discovered, Ezra abandoned his mission. He let his explosive charge loose, which floated into the East River where it exploded without causing any damage to British ships. Ezra made it safely back to Patriot whaling ships.
The Turtle never was able to deliver an explosive charge under a British ship. A second attempt was made without success and the Turtle project was abandoned. It would be nearly another century before Bushnell’s design was revisited and used as weapon. Although it’s mission failed, the design was pure genius. Lucky for Lord Admiral Howe, Washington used the submersible Turtle, and not the Teenage Mutant kind.
For more information about the Turtle check out Arthur Lefkowitz’s book The American Turtle Submarine: The Best-Kept Secret of the American Revolution.