Turtle (submersible)

The Turtle was the first manned submarine known to be used in combat during the Revolutionary War (1775–1783). It is also called the American Turtle. Built in 1775, the submersible was meant to be a means of sinking enemy British ships in the New York Harbor during the war. A man was able to fit inside the round vessel and control the movement of the submersible to travel out into the harbor and attach an explosive to the hull of an enemy ship. The underwater explosive was set to detonate on a delay. Its innovative design was a landmark invention in submersible watercraft and provided further inspiration for successive generations of inventors.

Brief History

The concept of the Turtle came from inventor David Bushnell, who was a Yale college student from Westbrook, Connecticut. He was trying to create a weapon that could be used against the British Navy while their ships were docked in the New York Harbor. He and fellow Yale student, Phineas Pratt, first developed a bomb that was able to detonate underwater and could be transported on a manually propelled submarine in 1775. They were able to attach a clockwork mechanism to a firing mechanism from a musket and provide enough of a delay in the detonation of the explosive.

Later that year, Bushnell took the idea he and Pratt developed a step further and began to work on a manned submersible that could be used to attach the explosive device to the wooden hull of a ship. He shared news of his progress with fellow patriot, Benjamin Franklin, and news of his idea spread. When the governor of Connecticut, Jonathan Trumbull, heard of the invention, he sent word to George Washington, commander of the Continental Army. Washington authorized support and funding for development and testing.

Bushnell found expert craftsmen who could help him bring to life his idea for his submersible vessel. It was first launched before dawn on the morning of September 7, 1776, in New York Harbor and was manned by a sergeant who targeted the HMS Eagle, a sixty-four-gun British frigate. The Turtle successfully maneuvered to the rudder of the ship, but since the boring mechanism struck a thick piece of metal rather than wood, it was unable to attach the explosive to the wooden part of the hull. The explosive was later discharged in an effort to distract the British from investigating the area near the ship, but no damage to any enemy ships was recorded. However, the Turtle was able to successfully return back to port.

Although two similar attempts were made to bomb British ships, the Turtle was ultimately unsuccessful to cause any significant damage. It was destroyed and any further plans for use were scrapped when the ship carrying it was sunk by the British. However, Bushnell’s innovation was lauded as being “an effort of genius” in a letter from George Washington to Thomas Jefferson in 1785.

Bushnell is said to have recovered the submersible, but it is unknown what became of it if he did actually find it. Despite this, replicas of the Turtle have been made according to Bushnell’s plans. These are on display and can be visited by tourists at the Connecticut River Museum and the US Navy Submarine Force Library and Museum, also in Connecticut. Outside of the United States, rebuilt Turtle submersibles are on view at the Oceanographic Museum of Monaco and the Royal Navy Submarine Museum in England.

Overview

The Turtle was named after the animal because of its similar appearance to a giant wooden and brass turtle. The hull of the vessel was barrel-shaped and made of oak held together with wrought iron hoops, which look like two large turtle shells joined together. Tar covered the hull, making it waterproof, and the door and much of the mechanical parts were made of brass. It was ten feet long, six feet tall, and three feet wide. One person could fit inside the vessel, and it held enough air in it to support the operator for about thirty minutes.

Water was let into a bilge tank at the bottom which allowed it to dive, and water could also be pumped out by hand to bring the vessel back to the surface. To create buoyancy, lead was kept on the hull and could be released by the operator as needed. Hand cranks and pedals controlled the propellers that moved it vertically and horizontally in the water, giving it a top speed of about 3 mph or 2.6 knots in calm waters.

The mechanical parts were crafted by New Haven, Connecticut, clockmaker and metal worker, Isaac Doolittle. He was known for his intricate design and manufacturing of clocks, printing presses, compasses, and surveying instruments. During the Revolutionary War, he also owned a brass foundry and a gunpowder mill, which he used to support the war effort. Bushnell took advantage of his skills and resources and used him to create much of the moving mechanisms and navigational equipment. The brass propeller used in the Turtle was the first known use of a propeller design in any type of watercraft, and was likely forged by Doolittle.

Doolittle was also instrumental in helping Bushnell create the auger attachment mechanism of the explosive the submersible was transporting. It was used to drill into the hull of the targeted ship and leave the explosive device behind. The fuse of the explosive could be lit from the surface by the operator, and the timing mechanism would create a sufficient delay in the explosion. However, strong currents and darkness made navigating the submersible quite a challenge, and this likely led to the lack of success of the Turtle in being able to successfully place an explosive on the hull of a ship in combat.

Bibliography

“Bushnell’s Turtle: A Revolutionary Submarine.” American Battlefield Trust, 25 July 2022, www.battlefields.org/learn/articles/head-tilting-history/bushnells-turtle-revolutionary-submarine. Accessed 9 Jan. 2023.

Giaimo, Cara. “The World’s First War Submarine Was Made of Wood, Tar, and a Bit of Metal.” Atlas Obscura, 7 Sept. 2018, www.atlasobscura.com/articles/american-turtle-first-submarine-battle. Accessed 9 Jan. 2023.

Rockwood, Heather. “The Turtle: Submarine Warfare during the American Revolution.” The Beehive, 22 June 2022, www.masshist.org/beehiveblog/2022/06/the-turtle-submarine-warfare-during-the-american-revolution/. Accessed 9 Jan. 2023.

Schenawolf, Harry. “The Turtle: Infernal Vessel Became the First Submarine Used in War.” Revolutionary War Journal, 31 Mar. 2022, www.revolutionarywarjournal.com/the-turtle-infernal-vessel-became-the-first-submarine-used-in-war/. Accessed 9 Jan. 2023.

“The Submarine Turtle: Naval Documents of the Revolutionary War.” Naval History and Heritage Command, 2 Nov. 2017, www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/s/submarine-turtle-naval-documents.html. Accessed 9 Jan. 2023.

“‘Turtle’ Submarine.” Connecticut River Museum, 2023, ctrivermuseum.org/turtle-submarine/. Accessed 9 Jan. 2023.