Not the first, but an important one
Calling the Turtle the “first submarine” is a stretch. Rowed underwater boats had been described in the early 1600s, and the Turtle was not the first of those. What makes it notable is that it appears to be the first submersible with a documented attempt to attack a warship in wartime, and it was designed from the start as a one-person weapon. The details below come mostly from letters and accounts written by the people involved, some of them years afterward, so a few points remain uncertain.
David Bushnell and the idea
David Bushnell was a Connecticut inventor who studied at Yale. Before the Turtle, he worked on underwater explosives, and by his own account he was interested in whether a charge could be set off against a ship’s hull without a crew being killed. The submersible craft was developed as a way to deliver such a charge. He began building it in about 1775, and trials in the Connecticut area followed with assistance from his brother Ezra, who helped operate it before he fell ill.
How the Turtle worked
Surviving descriptions, together with replicas built by modern researchers, give a reasonably good picture. The hull is usually described as egg-shaped or like two turtle shells joined together, and it was made of wood with iron bands and made watertight with tar-like sealant. It was about large enough for one seated person.
Its key features, as generally described, were:
- Water ballast. The operator let water in to sink and pumped it out to rise, using a foot-operated valve and a hand pump.
- Propellers. Two hand-cranked screw-like propellers, one for forward motion and one for moving vertically. These are often cited as an early use of the screw propeller principle underwater, though how effective they were is difficult to judge.
- A conning tower. A small tower with windows, fitted with a hatch, gave the operator some view of the surface.
- A detachable charge. An explosive held in a casing was meant to be attached to the enemy hull with a screw. It was fitted with a clockwork timer that would set off the black powder after the operator had gotten away.
The air in the compartment was limited, and descriptions suggest that the operator could stay submerged for only a short time, around half an hour at most. Accounts also refer to a depth gauge and a compass lit by a glowing material, but the exact fittings are less certain.
The 1776 attempt
In September 1776, British warships were anchored near New York as the Continental Army was being pushed out of the city. The Turtle was brought to the area, and Sergeant Ezra Lee, a volunteer who had trained in it, was chosen as the operator. During the night, he was towed out by rowboats and then moved toward HMS Eagle, a ship associated with Admiral Richard Howe.
According to Lee’s later account, he got under the ship but could not fix the charge to the hull. A common explanation is that the screw could not penetrate the bottom, perhaps because of metal fittings or copper sheathing. Historians have questioned this explanation, and it is difficult to confirm. Another possibility is that he had trouble holding the craft in position beneath a moving ship in the current.
Lee gave up and began to make his way back. Pursued for a time, he released the charge, and it exploded harmlessly in the water. The British, as far as accounts show, did not understand what had happened.
What became of it
Further attempts were made against other ships in the Hudson River, with no success. The craft is reported to have been lost when a vessel carrying it was sunk by British forces in the fall of 1776, though accounts differ about details. Bushnell later turned to floating mines, which also produced only limited results.
George Washington, who took an interest in the project, later wrote that it showed a great deal of ingenuity but that it was difficult to use. That assessment is a fair one.
Why it still matters
The Turtle is remembered because it combined the main elements of a combat submersible: ballast, propulsion and control by one person, and a plan for delivering a weapon. It did not work well enough to alter the outcome of the war. Its importance is as a proof of concept, and a reminder that the first attempts at a new weapon often fail and still lead others to try again. Today, replicas are displayed in several museums, and one built in the 1970s was tested in the water.