David Bushnell

David Bushnell (1742 - 1824) is the inventor of the first Sous-marin of combat, Turtle, in 1776.

Born in 1742 in Saybrook, Connecticut. Died in 1824 with Warrengton, Georgia.

It makes studies with Saybrook then works in the family farm. In 1771, with died of his/her father, it decides to sell the farm and settles with Yale where it begins scientific studies. In 1775, graduate of the university of Yale, it turns over to Saybrook.

The war of independence started. The British navy imposes a blockade on the American ports. Bushnell thinks of new weapons in the maritime field. Taking as a starting point drawings and descriptions former (like those of William Bourne, Cornelis Drebbel or Nathaniel Symons), including representations of the machine submarine of Alexandre Large the described by Aristote, it conceives the first true operational Sous-marin.

With the assistance of his Ezra brother, it will develop " The Turtle ", a kind of small sinkable ship (length 2.30 m, width 1.80 m). It consists of two identical parts out of wooden of Chêne of concave form, similar to two carapaces of tortoise (from where its name), united together and reinforced by iron bands. The hull is carefully worked and the joints are caulked before being covered with pitch. Stability is ensured by a lead ballast. A tank ballast which one fills by opening a valve and which one can empty with two manual brass pumps makes it possible to control buoyancy.

The machine is designed to be operated by only one operator sitting in the center. It has in front of him of the cranks horizontal and vertical propulsion by Hélice S primitives, as well as Gouvernail. A small kiosk equipped with port-holes and an opening panel overcomes the unit. A kind of ordered drill of the interior must make it possible to fix the explosive load, transported behind kiosk, on the hull of the enemy ship. Bushnell, in spite of limited means, managed to solve the majority of the encountered engineering problems: sealing and pressure resistance of water, propulsion, stabilization, direction and armament.

Autonomy in diving was of approximately thirty minutes. Because of its low speed, the machine was to be towed with more close to the objective.

The tests carried out in the Connecticut River require several developments, however the machine is ready at spring 1776. The generals Israel Putnam and George Washington give their agreement and make transport in secrecy the machine until New York, where it is placed under the authority of the Putnam General. Ezra Bushnell begins long series of drive to familiarize itself with the conditions of currents and tides of bay of New York. But beginning July 1776, whereas beautiful attack appropriatenesses arise, Ezra Bushnell falls ill and must be replaced. Among the volunteers, the sergeant Ezra Lee is appointed and must involve himself intensively during several weeks.

It is the September 6th 1776 which the attack will have place. The HMS Eagle, ship British of 64 guns, is wet between Staten Island and Governor' S Island (where the Statue of Freedom is today). In the middle of the night, The Turtle, towed by a Chaloupe, is as brought close as possible of the enemy. The Lee sergeant only embarks and continues. Lee approaches the HMS Eagle and makes plunge The Turtle in order to come to position under the ship. It tries during long minutes to drill the hull to fix the explosive load at it. Oxygen has suddenly missed, it is constrained to move away and remake surface to renew the air. It tries once again to fix the load without success, obstructed by the copper shielding of the hull with which certain British ships are equipped or by a metal part of reinforcement. Exhausted, Lee must face several dangers whereas the day will rise. It must fight of all its forces against the tide which risks to involve it towards the broad one and to escape the British soldiers who patrol. To make diversion or to become lighter it decides to get rid of the explosive load. This one drifting with the wire of the current is not long in going to explode on the side of the British vessels causing a beautiful panic. The British fleet weighs the anchor to gain sourer water. The sergeant Lee and The Turtle did not succeed in destroying the British vessel, but by this action, they caused the rupture of the blockade of New York.

Other attempts will be also balanced by failures and finally The Turtle will be destroyed when the sloop which transported it was run by a British frigate.

Following its results and into the regard of the General George Washington, Bushnell integrated the body of the engineers of US Army, which it directed starting from 1783. It continued its studies on the design of submarines, but was also devoted to the use of the naval mines which one names at that time (and for more than one century still) " Torpedo ".

Towards 1795, it travelled in England and France to present its concept of Sous-marin to admiralties. It met another large American inventor, Robert Fulton. Perhaps it in its project of submarine helped it. Disillusioned in front of the little of enthusiasm met by its idea as well in Europe as with the the United States, it returned to America and resumed studies of medicine. It settled, under a name of loan, as expert with Warrengton, Georgia. It dies there in 1824, at the 82 years age.

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