David Bushnell of Westbrook, Connecticut

Westbrook, Connecticut

Westbrook is a town in Middlesex County, Connecticut, United States. The population was 6,292 at the 2000 census. The town center is also classified by the U.S. Census Bureau as a census-designated place .-Geography:...

, was an American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 inventor during the Revolutionary War

American Revolutionary War

The American Revolutionary War , the American War of Independence, or simply the Revolutionary War, began as a war between the Kingdom of Great Britain and thirteen British colonies in North America, and ended in a global war between several European great powers.The war was the result of the...

. He is credited with creating the first submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 ever used in combat, while studying at Yale University

Yale University

Yale University is a private, Ivy League university located in New Haven, Connecticut, United States. Founded in 1701 in the Colony of Connecticut, the university is the third-oldest institution of higher education in the United States...

 in 1775. He called it the Turtle

Turtle (submarine)

The 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...

 because of its look in the water. His idea of using water as ballast for submerging and raising his submarine is still in use today, as is the screw propeller, which was used in the Turtle.

While at Yale, he proved that gunpowder

Gunpowder

Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...

 exploded under water.