The American Revolutionary War marked a period of great expansion in maritime history. One of the most significant developments was the invention of the first combat submarine: the submergible attack vessel known as the Turtle, designed by David Bushnell.
At the start of the Revolution, David Bushnell (1740–1824) was a student at Yale where he excelled in the research of explosives. Of particular note, Bushnell created a process that allowed gunpowder to explode under water, and he delighted in fraying the nerves of his classmates with his experiments.
Bushnell left Yale in the spring of 1775 with the advent of the Revolution. By early 1776, David and his brother Ezra had created what came to be known as the Turtle, so named because it resembled two turtle shells joined together. George Washington gave the go-ahead for the Turtle to embark on its first mission in the fall of 1776. The target was the British Flagship HMS Eagle helmed by Admiral Richard Howe, who was then orchestrating a naval blockade in the New York Harbor.
On the night of September 6, 1776, volunteer Ezra Lee rowed the Turtle to the middle of the Harbor, and then navigated the submergible right up to the side of the Eagle. “I could see men and deck and hear them talk,” Lee recounted later. “Then I shut all doors, sunk down, and came up under the bottom of the ship.” Lee then maneuvered the Turtle “up with the screw against the bottom but found that it would not enter.” The hull of the Eagle had been plated with copper to protect it from barnacles and parasites. Lee tried in vain to attach a mine with an explosive package of about 150 lbs of gunpowder, but the Turtle’s screw could not find purchase in the Eagle’s hull.
Out of time and air, Lee paddled the Turtle away and detonated the mine in the harbor. The explosion startled the crew of the Eagle, and they immediately sailed the Eagle further from land.
The Turtle is credited as the first submerged vessel used in combat. It is argued that due to the Turtle’s attack on the Eagle, the British navy was reluctant to come close to shore, which kept them from doing much damage to mainland targets.
Roy R. Manstan and Frederic J. Frese, Turtle: David Bushnell’s Revolutionary Vessel (Yardley, PA: Westholme Publishing, 2010).
Bushnell's American Turtle
A Seascape, Shipping by Moonlight, c. 1864