The Turtle

In 1870, when Jules Verne wrote Twenty Thousand Leagues Under the Sea, the idea of a submarine was still a fantasy. It is hard to believe that the technology would be available to create such a piece of machinery in the 19th century. While Verne was ahead of his time with the description of his vessel called Nautilus, the fact remains that Verne based his idea of a submarine on the very real advancements that were being made at the time. Around the world, inventors were working on different methods to create a usable model.  By the time Twenty Thousand Leagues had hit the bookshelves, a submarine had already been used in war  multiple times. In 1863, the H.L. Hunley sank the USS Housatonic during the Civil War. And on September 7, 1776, the world’s first submarine attack was reordered during the American Revolution.

In 1740, in what is today Westbrook, Connecticut, David Bushnell was born. He was the eldest of five children, and by the time he was 26, inherited his family farm which he ran with his brother Ezra. David left the farm in 1771 to study at Yale. His studies included mathematics, religion, and natural philosophy, and he was known for doing experiments with gunfire underwater. It was during his last year at Yale that news broke about the battles at Lexington and Concord. The revolution had begun, school was shut down, and David returned to his family farm. With war raging, David set out to build a submarine that could deliver underwater explosions that would help ended British efforts. This submarine became The Turtle.

Figure 1 Print shows three views of the “Turtle”, a one-man submarine designed and built by David Bushnell to attach bombs to British warships during the American revolutionary war.

He knew that his device couldn’t simply dive while connected to ropes. David knew that to make an effective weapon, his device needed to be fully submerged, be able to move through the water and, when ready, come back to the surface. Bushnell’s submarine was constructed out of oak, in a barrel shape and bound by heavy iron hoops. To solve the problem of how to submerge the vessel, David decided that the operator would flood the chamber with water, making it heavier as needed to achieve the desired depth. This air-filled chamber was manufactured by Isaac Doolittle, a clockmaker, using specially made valves and pumps. A real ballast was placed on the outside and carried through to the inside to help with stabilization. A front propeller was used to help propel the vessel forward and backwards while a vertical propeller was placed on the top to help with the ascent. Both propellers were operated by a hand crank. To provide air to the single operator inside the boat, two snorkels were places in the chamber that closed over when the boat submerged. Because air was limited, the submarine was designed to stay at the surface until it had to submerge to avoid detection. One of the largest problems that faced The Turtle was the mine that was filled with gunpowder and was attached to the enemy ship. To help Bushnell with this, Doolittle and Phineas Pratt modified a clockwork timing device to trigger a flint from a musket. The sparks would ignite the powder and set it off. The idea was that the operator of the submarine would set off the timing device, leaving him enough time to clear the area.


Figure 2 Ezra Lee

Once The Turtle was deemed seaworthy, she began trials which quickly caught the attention of Benjamin Franklin and George Washington. In June of 1776, a British force began to move into New York Harbor carrying supplies and soldiers. Bushnell hoped that sinking the HMS Eagle, the flagship of British Admiral Howe, would be a decisive blow for the British troops. Upon arriving in New York, the operator who had been trained to run the submarine, Ezra Bushnell came down with a fever. Ezra Lee, of Lyme, Connecticut was selected to be the new pilot. Little is known about Lee except that he was a colonial solider who was selected for the mission by his brother-in-law Brigadier General Samuel Holden Parsons. To avoid being discovered, the Turtle, Lee and Bushnell returned to Connecticut to train in secret. After two weeks of training, the mission was scheduled. On September 7, 1776, Lee set out on his mission to sink the HMS Eagle. Due to the tide, Lee couldn’t maneuver the propellers properly and spent two hours in the water unable to submerge below the British ship. Ezra Lee described the event saying, “When I rowed under the stern of the ship, could see men and deck and hear them talk-then I shut all doors, sunk down, and came up under the bottom of the ship, up with the screw against the bottom but found that it would not enter.”[1] The boring tools attached to The Turtle that would allow Lee to attach the mining device, could not penetrate the iron sheathing on the bottom of the ship. By this time, daylight had begun to break, so Lee headed for shore, hoping to not be detected. British guards on Governors Island saw the craft and made their way towards Lee. Ezra Lee described what happened next by saying, “he let loose the magazine (mine) in hopes, that if they should take me, they should likewise pick up the magazine, and then we should all be blown up together.”[2] The magazine would explode in open water, scaring off the guard boats and allowing Lee and The Turtle to escape. In the following week, the Turtle made several attempts to sink British ships. However, all were unsuccessful. Only Bushnell was fully capable of understanding the submarines complicated functions. However, due to physical limitations, he was unable to power the device himself. The Turtle was lost during the Battle of Fort Lee when the sloop transporting her was sunk by the British.

Bushnell would go on to develop other underwater mines that could be delivered without a submarine. One was used in New London Harbor and the other in the Delaware River, both with successful results. After the war ended, Bushnell would move to Warrenton, Georgia and teach at Franklin College. He died in 1826 while working on a floating torpedo for the US Navy. Bushnell’s device was made known to the public in 1798 by Thomas Jefferson, who used a letter written by Bushnell in 1787 about the details of his inventions. Bushnell is known as the Father of Submarine Warfare. The two propellers on the Turtle were his greatest contribution to submarine development. Like Bushnell’s original design, navies around the world mimicked marine animals natural designs in their hull structures.  Despite its shortcomings, The Turtle marked an important milestone in submarine development. Bushnell created a military vantage point that had yet to be seen. And even though the Turtle failed its mission, it served as an important symbol of American inventions at a time when America was just beginning to discover its identity. Submarine development has come a long way since Bushnell’s time, becoming an essential member of naval warfare.  A replica of Bushnell’s Turtle is on display at the Submarine Force Museum.

Replica of the Turtle at Submarine Force Museum

Replica of the Turtle at the Submarine Force Museum



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