David was born in Saybrook, Connecticut about 1742. When his father died, David sold his portion of the estate and used the money to attend college at Yale. During his freshman year an instructor told the class that gunpowder would not explode underwater. This statement interested him, so he decided to see for himself. He found that not only will gunpowder go of under water, but its force was greatly increased, since the density of the water kept the force of the explosion form being dissipated. (Note to Jim, James, Zach and Nathaniel and any other young inventors--- DO NOT TRY THIS AT HOME!!)

This got Bushnell thinking about making explosive bombs to attach to the hulls of warships. Which in turn made him wonder about how to put them there without being detected. In 1775 he built "The American Turtle" at his home in Saybrook, CT and tested it in the Connecticut River. At this time in history the American Colonies had not declared their independence, but fighting had broken out in a few places and war was eminent. The craft was built in secrecy. It was very advanced for it's time including several items never before seen, such as the pressure operated depth gauge, conning tower and screw propeller. Although no plans or diagrams of the Turtle were left by Bushnell. Historians tell us that it was roughly egg shaped with the small end of the egg down. The bottom held a large lead weight to hold the craft upright. The operator used the 2 propellers to guide the craft up and down or forward and backward, there was also a rudder and 2 pumps for getting water in and out of ballast tank.

To submerge the operator used one foot to let water into the ballast tank, which is located on the back above the rudder. This determined how heavy the turtle was and how high in the water it floated. Letting in more water made the turtle sink, pumping water out made it float. (Note: This you can try, boys)

The Turtle ran with it's top just above the surface so the driver could see out the windows in the top. The idea was to sneak up as close as possible to the ship and then submerge completely. When submerged he would use his compass to guide him to where he wanted to be. The operator could tell how deep he was from a pressure-operated depth gauge invented by Bushnell. Here, in an excerpt of a letter he wrote to Thomas Jefferson in 1787, David Bushnell tells about the depth gauge.

A glass tube eighteen inches long and one inch in diameter, standing upright, its upper end closed and its lower end, which was open, screwed into a brass pipe, through which the external water had a passage into the glass tube, served as a water-gauge or barometer. There was a piece of cork with phosphorus on it, put into the water-gauge. When the vessel descended the water rose in the water-gauge, condensing the air within and bearing the cork with its phosphorus the ascent of the water in the gauge was rendered visible, and the depth of the vessel under water ascertained by a graduated line.

When the Turtle was under the hull of the enemy ship the plan was to attach a big bomb that contained 150 lbs of gunpowder, to the bottom of the ship. To do this the operator would use a big screw to drill into the wooden bottom of the ship. The mine was tied to the screw with a short rope and because the mine floated, it would be pushed up against the bottom of the ship. The bomb was set to go off with a timer, giving the Turtle time to get away.

Bushnell showed his invention to the governor of the some of the political leaders of the time. George Washington, and others took interested in it and provided funds and munitions for the project. In 1776 The American Turtle was the first submarine to be used in combat, when it was sent to blow up the flagship of the British fleet, the H.M.S. Eagle, a fifty-gun frigate.

David's brother, Ezra Bushnell was to be the operator, but he fell ill and didn't recover strength enough to operate the propeller crank, so Ezra Lee stepped in to pilot the complicated craft. The turtle was towed close to the British fleet after dark and Lee positioned it under the hull of the Eagle. Unfortunately he could not get the screw to attach to the hull. Some accounts say that the reason was because there was a copper sheeting covering the hull, others say the British did not use sheeting at that time, claiming he must have hit a bolt, or an Iron strap that supported the rudder, but we know for sure that the screw was not able to get a bite. After struggling with it for some time the air in the turtle was becoming exhausted and Lee was forced to surface. He released the bomb in hopes that it would do some good, and headed for shore. Dawn was coming and he was spotted but was able to escape. The bomb exploded, doing no damage but letting the British know that the Colonists had a new and different way to attack their ships.

Modern science may have discovered at least part of the reason for the failure. It is now believed lack of oxygen may have caused the illness of Ezra Bushnell and contributed to the inability of Lee to complete the missions. It took two hours to peddle the turtle to the target, all the while steering, and adjusting the ballast tanks. By the time Lee reached his target he must have been exhausted. Then when submerged under the giant hull of the Eagle Lee was in total darkness, but would still have to keep menouvering his craft in the water currents to maintain his position. Having adjusted the ballast to be submerged there would not have been much weight to push the screw up into the hull. Add to this the disorientation that comes with carbon monoxide poisoning, and the knowledge that he was carrying a 150 pound time-bomb, and it isn't hard to see why the mission failed. In spite of its failier, George Washington later wrote, "I then thought, and I still think, that it was an effort of genius." The mission is remembered, not because it failed, but because it so nearly succeeded. Exploding a charge next to the bottom of s ship would have been a far better means of attack. At that time ships were rarely sunk by gunfire alone. Ships can take a large amount of damage to the portion above the water line and still float, but knock a whole below the water line and they are soon out of commission, destroying the ship completely, and taking most of the crew down with it.

Some weeks later another attack was planned this time in the Hudson River. This time Lee lost track of his target in the river current. Before he was able to work his way back, the tide had come in and it swept him away again.

The Turtle was sunk by cannon fire while it was being taken to its next mission. It was recovered, but never used again. It is said that they dismantled it then, before it could be discovered by the British.

Bushnell was not finished yet though. One December night, he packed several kegs with gunpowder and sent them floating down the Delaware River with the current toward the fleet that was guarding Philadelphia. Unfortunately the kegs were launched too far up stream and ice stopped them. They were free again in the morning but clearly visible in the light of. The British went to investigate one of the kegs. It's detonator was set to go off when it touched something and it exploded killing 3 soldiers and sinking their rowboat. The British stationed troops on both banks of the river shooting away at everything that floated. This is known as "The Battle of the Kegs" and was a favorite story among the revolutionary soldiers and was made into a song by Francis Hopkins. After serving a as captain-lieutenant and later Captain in the military unit known as the Corps of Sappers and miners" On May 6 1779 he was taken prisoner in Middlesex Parish, now Darien, Connecticut. After peace was declared he returned home with some honor, but with a large amount of ridicule. It was then considered unsportsmen-like, or at least ungentlemanly to attack an enemy under cover and destroy them without giving him the opportunity to fight back. A very different view from that held today.

Bushnell became discouraged and moved to France. In 1795/6 he returned to the United States and settled in Georgia, where he went by the name of Bush. He practiced medicine for many years and it wasn't known until the will was read following his death in about 1823, that he was one of the greatest inventors and geniuses of his time.

Bibliography

Vessels for Underwater Exploration, by Peter R. Limburg and James B. Sweeney, Copyright 1973 by Crown Publishers, Inc. 419 Park Avenue South, New York NY 10016 pp. 32-35.

From the Turtle to the Nautilus, by Edwin P. Hoyt Illustrated by Charles Geer, Copyright 1963, Little Brown and Company

Submarines, by Anthony Preston Copyright 1982 by Gallery books, a division of WH Smith Publishers 112 Madison Avenue, Nee York NY 10016.

Bushnell Family Genealogy- Ancestry and Posterity of Francis Bushnell (1580-1646) of Horsham, England and Guilford, CT by George Eleazer Bushnell, Copyright 1945. Nashville TN.

Navies of the American Revolution by Anthony Preston, David Lyon and John H. Batchelor, Copyright 1975, Published by Prentice Hall Inc, Endlewood Cliffs, NJ

.	Back to Shirley's Genealogy page Back to Shirley's Homepage Email me!