David Bushnell




NA/New England region


Maritime Republic (1751-1815)








Inventor. By the time Bushnell entered Yale, he had developed concepts for both a submarine and an underwater explosive. At college, he experimented with gunpowder and proved that it could explode underwater. During the summer of 1775, the year he graduated, the thirteen colonies were in the throes of revolt against Great Britain, and Bushnell felt that an offensive weapon would be a useful tool against the Royal Navy in the ensuing conflict. With that in mind, he constructed his submarine in Saybrook during the spring and summer of 1775. Although he was secretive about his work, several colonial notables knew of it, including Ben Franklin.

The rudimentary wooden submarine, which was six feet high and seven and one-half feet long, resembled a tortoise with its two external shells joined together, hence the nameAmerican Turtle. A one-man operation, it held enough air to sustain the occupant for thirty minutes. The entrance to the vessel was elliptical and had a brass watertight cover that was screwed shut by the operator. Inside a brass crown atop the cover were three round doors that could be opened to admit air. There were several small windows for light and two air pipes, one for admitting air and the other for expelling air via a ventilator. The pipes automatically shut when the vessel was below water and opened when it surfaced. The vessel was ballasted with lead, which could be discarded if the operator needed to surface quickly. Inside, there was an oar for rowing, a rudder for steering, an oar for ascending and descending, an aperture with a valve for admitting water for descending, and two brass pumps to eject the water when ascending. A compass determined the course, and a barometer measured descent. The purpose of the submarine was to carry and deliver a powder magazine that could destroy a ship. A woodscrew would be fastened to the hull of a ship, and a rope would connect the magazine to the screw. The magazine contained a timing mechanism that sprung a lock that fired the powder.

By the summer of 1776 the Turtle was ready to go into action. A massive British fleet had assembled off New York City under Admiral Richard Howe in his flagship HMS Eagle. At this crucial time, Bushnell put the Turtle on a sloop and headed for Manhattan with its operator, Sergeant Ezra Lee of Lyme, Connecticut, to test the sub against the British fleet. On the night of 6 September 1776 the Turtle was towed out to HMS Eagle, just above Staten Island. Sergeant Lee attempted to affix the explosive to the ship's hull, but the auger hit an iron bar and he was forced to give up. Before he was rescued by the Americans, he detonated the mine. The mission was not a success, but it proved that the submarine and the mine were operable.

Not easily defeated, Bushnell's operator made two other futile attempts on British ships anchored off Fort Lee, New Jersey. Each time the sub was detected by alert seamen, and the attack was foiled. Bushnell gave up on this enterprise because, as he explained in a letter to Thomas Jefferson in October 1787, "the situation of public affairs was such, that I despaired of obtaining the public attention, and the assistance necessary. I was unable to support myself, . . . Beside I found it absolutely necessary, that the operators should acquire more skill in the management of the Vessel, before I could expect success" (Morgan, vol. 6, pp. 1506-7).

Bushnell next turned to naval mines as a way to harass the British. He constructed two mines for the attack on the HMS Cerberus anchored in Black Point Bay, between New London and Saybrook, on 13 August 1777. Each mine consisted of two twenty-inch-long, twelve-inch-wide iron vessels connected by two wheel-like iron bars at each end. An iron tube lay between the bars. The upper vessel projected above the water, while the lower one, below the water, contained the powder. The two mines were connected by a line 600 yards long. The mines were set adrift, and one landed near the Cerberus, but the ship's captain cut the line and averted an explosion. Instead, the mine demolished a schooner astern of the frigate, killing three men and injuring one.

In December 1777 Bushnell was in Bordentown, New Jersey, where he devised plans to harass the British who occupied Philadelphia. He designed a mine that exploded on contact using a springlock device as a detonator. The mines were suspended below kegs tied together by rope and then set afloat. In late December the floating mines were sent down the Delaware River toward the British ships at anchor near Philadelphia, but by then some of the ships had left. Despite the fact that the mines did not reach their intended targets, they exploded and scared the British into firing at any floating object they saw in the Delaware. This encounter, known as the Battle of the Kegs, was immortalized in a poem by Francis Hopkinson.

An example of Yankee ingenuity at its best, Bushnell received the epithet "Father of Submarine Warfare" because he constructed the first practical, functioning underwater vessel that met the criteria of a modern submarine. It was maneuverable and submersible, had a sufficient air supply, and carried an offensive weapon. Coupled with his naval mines and rudimentary torpedoes, Bushnell's vessel showed him to be a true pioneer in the development of undersea warfare.

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Date: 1875
Image Id: 403

Record ID: 314