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A cut-away full size replica of the Turtle on display at the Royal Navy Submarine Museum, Gosport, UK

The Turtle (also called the American Turtle) was the world's first submersible with a documented record of use in combat. It was built in Old Saybrook, Connecticut in 1775 by American Patriot David Bushnell as a means of attaching explosive charges to ships in a harbor. Bushnell designed it for use against British Royal Navy vessels occupying North American harbors during the American Revolutionary War. Connecticut Governor Jonathan Trumbull recommended the invention to George Washington; although the commander-in-chief had doubts, he provided funds and support for the development and testing of the machine.

Several attempts were made using the Turtle to affix explosives to the undersides of British warships in New York Harbor in 1776. All failed, and her transport ship was sunk later that year by the British with the submarine aboard. Bushnell claimed eventually to have recovered the machine, but its final fate is unknown. Modern functional replicas of the Turtle have been constructed; the Connecticut River Museum, the Submarine Force Library and Museum, and the Royal Navy Submarine Museum have them on display.


This 19th-century diagram shows the side views of the Turtle. It incorrectly depicts the propeller as a screw blade; as seen in the replica photographed above and reported by Sergeant Lee, it was a paddle propeller blade.[1]

In the early 1770s, Yale College freshman David Bushnell began experimenting with underwater explosives. By 1775, with tensions on the rise between the Thirteen Colonies and Great Britain, Bushnell had practically perfected these explosives.[2] That year he also began work near Old Saybrook, Connecticut on a small manned submersible craft that would be capable of affixing such a charge to the hull of a ship. The charge would then be detonated by a clockwork mechanism that released a musket firing mechanism, probably a flintlock, that had been adapted for the purpose.[3] According to Dr. Benjamin Gale, a doctor who taught at Yale, the firing mechanism and other mechanical parts of the submarine were manufactured by a New Haven clockmaker named Isaac Doolittle.[4]

Named for its shape, Turtle resembled a large clam as much as a turtle; it was about 10 feet (3.0 m) long (according to the original specifications), 6 feet (1.8 m) tall, and about 3 feet (0.9 m) wide, and consisted of two wooden shells covered with tar and reinforced with steel bands.[5] It dived by allowing water into a bilge tank at the bottom of the vessel and ascended by pushing water out through a hand pump. It was propelled vertically and horizontally by hand-cranked propellers. It also had 200 pounds (91 kg) of lead aboard, which could be released in a moment to increase buoyancy. Manned and operated by one person, the vessel contained enough air for about thirty minutes and had a speed in calm water of about three miles per hour (5 km/h).[5]

A diagram showing the front and rear of the Turtle

Six small pieces of thick glass in the top of the submarine provided natural light.[5] Illumination while submerged was provided by a piece of cork that gave off a fungus-powered bioluminescent foxfire. During trials in November 1775, Bushnell discovered that this illumination failed when the temperature dropped too low. Although repeated requests were made to Benjamin Franklin for possible alternatives, none were forthcoming, and the Turtle was sidelined for the winter.[6]

Bushnell's basic design included some elements present in earlier experimental submersibles. The method of raising and lowering the vessel was similar to that developed by Nathaniel Simons in 1729, and the gaskets used to make watertight connections around the connections between the internal and external controls also may have come from Simons, who constructed a submersible based on a 17th-century Italian design by Giovanni Alfonso Borelli.[7]

Preparation for use

Drawing of a cutaway view of Turtle's interior.

Bushnell's work began to receive more attention in August 1775, when Franklin was informed of it.[3] Despite Bushnell's insistence on secrecy surrounding his work, news of it quickly made its way to the British, abetted by a Loyalist spy working for New York Congressman James Duane. On November 16, 1775, a coded message to William Tryon, the last royal governor of the Province of New York, brought Bushnell's work to British attention. The details of the report were highly inaccurate, implying that the Turtle was nearly ready to be deployed in Boston harbor against the fleet that was part of the British siege effort there. In fact Bushnell and his brother Ezra were still testing the machine in the Connecticut River.[8] In the spring of 1776, after the British withdrew from Boston, Bushnell offered the submarine to General George Washington for use in the defense of New York City. Washington agreed, and provided some funding to the inventor to prepare the vessel for deployment.[9]

In August 1776 Bushnell asked General Samuel Holden Parsons for volunteers to operate the Turtle, because his brother Ezra, who had been its operator during earlier trials, was taken ill.[10] Three men were chosen, and the submarine was taken to Long Island Sound for training and further trials.[11] While these trials went on, the British gained control of western Long Island in the August 27 Battle of Long Island. Since the British now controlled the harbor, the Turtle was transported overland from New Rochelle to the Hudson River.[11]

Attack on the Eagle

Portrait of Ezra Lee, the Turtle's operator

General Washington then authorized an expedition by the Turtle in the waters of New York Harbor.[12] At 11:00 PM on September 6,[1] one of the volunteers, Sergeant Ezra Lee, took the Turtle out to attempt an attack on Admiral Richard Howe's flagship HMS Eagle.[11] She was moored off what is today called Governors Island, which is due south of Manhattan.[13] According to Lee's account, she was towed by rowboats as close as was felt safe to the British fleet. He then navigated for more than two hours before slack tide made it possible to reach the Eagle. His first attempt to attach the explosive failed because the screw struck a metal impediment.[1] A common misconception was that Lee failed because he could not manage to bore through the copper-sheeted hull. Bushnell believed that Lee's failure was probably due to an iron plate connected to the ship's rudder hinge.[14] When Lee attempted another spot in the hull, he was unable to stay beneath the ship, and eventually abandoned the attempt. Lee reported that British soldiers on Governors Island spotted the submarine and rowed out to investigate. He then released the charge (which he called a "torpedo"), "expecting that they would seize that likewise, and thus all would be blown to atoms."[14] Suspicious of the drifting charge, the British retreated back to the island. Lee reported that the charge drifted into the East River, where it exploded "with tremendous violence, throwing large columns of water and pieces of wood that composed it high into the air."[14] It was the first recorded use of a submarine to attack a ship;[7] however, the only records documenting it are American. British records contain no accounts of an attack by a submarine or any reports of explosions on the night of the supposed attack on HMS Eagle.[15]

According to British naval historian Richard Compton-Hall, the problems of achieving neutral buoyancy would have rendered the vertical propeller useless. The route the Turtle would have had to take to attack HMS Eagle was slightly across the tidal stream which would, in all probability, have resulted in Ezra Lee becoming exhausted.[15] In the face of these and other problems Compton-Hall suggests that the entire story was fabricated as disinformation and morale-boosting propaganda, and that if Ezra Lee did carry out an attack it was in a covered rowing boat rather than the Turtle.[15]


File:Bushnell mines.jpg

Bushnell mines destroying a British ship

On October 5, Sergeant Lee again went out in an attempt to attach the charge to a frigate anchored off Manhattan. He reported that the ship's watch spotted him, so he abandoned the attempt. The submarine was sunk some days later by the British as it sat on its tender vessel near Fort Lee, New Jersey. Bushnell reported salvaging the Turtle, but its final fate is unknown.[16] George Washington wrote of the attempt that it was "an effort of genius", but that "a combination of too many things was requisite" for such an attempt to succeed.[17]

In 1777, Lee used floating mines in an attempt to destroy the British frigate HMS Cerberus, anchored in Niantic Bay. The explosion was said to have killed three sailors and destroyed a prize schooner anchored astern of the Cerberus, although it left the Cerberus undamaged.[18] In 1778 Bushnell floated mines down the Delaware River in an attempt to destroy British ships off Philadelphia. The mines took longer to reach the area than expected, and there was a report that two boys investigating them were blown up.[19] On January 5, 1778, one of the mines struck a British barge, killing four men and raising the alarm. The British response, in which virtually any piece of floating wood in the river became a target, was lampooned in a ballad called "The Battle of the Kegs".[20]


Replica at the Connecticut River Museum

In 1976, a replica was designed by Joseph Leary and constructed by Fred Frese as a project marking the United States Bicentennial. It was christened by Connecticut's governor, Ella Grasso, and later tested in the Connecticut River. This replica is owned by the Connecticut River Museum.[21]

On August 3, 2007 three men were stopped by police while escorting and piloting a replica of the Turtle within 200 feet (61 m) of the Queen Mary 2, then docked at the cruise ship terminal in Red Hook, Brooklyn. The replica was created by New York artist Philip "Duke" Riley and two residents of Rhode Island, one of whom claimed to be a descendant of David Bushnell. The Coast Guard issued Riley a citation for having an unsafe vessel, and for violating the security zone around the Queen Mary 2.[22]


  1. 1.0 1.1 1.2 Rindskopf et al, p. 30
  2. Diamant, p. 21
  3. 3.0 3.1 Diamant, p. 22
  4. Diamant, p. 23
  5. 5.0 5.1 5.2 Schecter, p. 172
  6. Diamant, p. 27
  7. 7.0 7.1 Rindskopf et al, p. 29
  8. Diamant, p. 26
  9. DANFS Turtle I
  10. Diamant, p. 30
  11. 11.0 11.1 11.2 Schecter, p. 173
  12. Shecter, p. 171
  13. Diamant, p. 31
  14. 14.0 14.1 14.2 Schecter, p. 174
  15. 15.0 15.1 15.2 Compton-Hall, pp. 32–40
  16. Diamant, p. 33
  17. Diamant, p. 34
  18. Sleeman, p. 290
  19. Scudder .p.230
  20. Coggins, p. 97
  21. Connecticut River Museum – David Bushnell's Turtle
  22. Makeshift submarine found in East River


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