America's First Submarine

By DAVID F. WINKLER

On the night of 6/7 September 1776, Ezra Lee maneuvered the Turtle through New York harbor and brought it alongside HMS Eagle, flagship of British Admiral Richard Howe, in a vain attempt to attach an explosive charge to the Eagle's hull. That this and a subsequent mission both failed cannot be attributed to the plan's concept, as would be demonstrated--more than 227 years later--by a professor at the U.S. Naval Academy (USNA).

Designed and built by Connecticut farmer David Bushnell, the Turtle was, by the standards of that time, incredibly sophisticated. Aptly named because of her more or less spherical-like shape, the Turtle would take advantage of the water currents and her own three hand-cranked two-bladed propellers to move through the water. For fore-and-aft motion, Lee had to turn a crank attached to a shaft that ran through the bow of the submersible. In addition to a small rudder aft, Bushnell installed a propeller on the port side to facilitate underwater horizontal rotation. A third shaft, which pierced the wooden hull vertically, provided a degree of diving ability.

However, Bushnell's installation of a foot-operated seacock is what made Turtle truly submersible. When Lee opened the seacock, water slowly filled the bottom of the chamber. To remove the water, Lee used his foot to operate a discharge pump. In an emergency, though, he could release a heavy lead weight that Bushnell had latched onto the keel. To help Lee gauge his depth and position, Bushnell installed a mercury bar-ometer and a compass.

Two brass tubes protruding from the sphere provided oxygen. However, over two centuries later it became evident that this air-intake system hardly sufficed. Bushnell also realized that illumination by interior candlelight exacerbated the situation. However, because Lee had to maneuver Turtle under the cover of darkness for any hope of success, he had to see his gauges. Foxfire--a phosphorescent fungus found on rotting wood--proved to be the answer. Bushnell put chunks of the material on the mercury depth gauge and on the needle tip of the compass.

To enter Turtle, Lee opened a hatch fitted with viewing ports. Once underway he could poke his head into the hatch and take a peek as the Turtle moved along the surface.

What made Turtle into a weapon-delivery system was an auger it carried that was designed to drill a bit into the hull of an enemy warship; a keg of gunpowder attached to the bit provided a lethal albeit cumbersome weapon. As Lee cranked the Turtle away from its target, a line tethered to the submersible would pull a lanyard, attached to an igniter, to set off the explosion.

Last fall, Naval Academy midshipmen conducted extensive historical research in an effort to revive and review Bushnell's design. Under a cooperative arrangement underwritten by television's Discovery Channel, students at the Massachusetts College of Art split and carved out a spruce tree trunk to form the two shells of the new Turtle. On 15 January 2003, the submersible was successfully launched, then tested, in Snug Harbor at Duxbury, Mass.

Brought down to Annapolis, the new Turtle was placed in a large tow tank at the Academy's Hydromechanics Lab. USNA Professor Lew Nuckols took the controls and was able to move the vessel through the tank at 0.7 mph. Further tests indicated, though, that, because of carbon dioxide buildup, Nuckols could stay submerged for only 30 minutes. After a mock enemy hull also was put into the tank, Nuckols attempted to simulate the attack on the Eagle. On the third try he succeeded in boring the bit into the wood and leaving an explosive charge. In 1776, Lee had claimed that, because of her coppering, he could not penetrate the Eagle's hull. After copper was installed on the mock hull earlier this year, Nuckols found that he also could not make even a dent in it.

Given his ingenuity, Bushnell might well have figured out a solution to the problem. In any case, British advances up the Hudson precluded further development of the Turtle's design. Still, despite the failed attacks, Bushnell must be credited with conceiving and incorporating several design elements in the U.S. Navy's first submersible that remain valid to this day. n

Sources: Capt. Donald H. Kern, USN (Ret.), Submarine Roots, United States Submarines, Naval Submarine League 2002; Judy Campbell, "Turtle Lives Again as Replica Surfaces at Academy," Navy Newsstand, www.news.navy.mil.

Dr. David F. Winkler is a historian with the Naval Historical Foundation.