The submarine is one of the greatest naval inventions in the history of war. This innovation allows men to dive to certain depths in the open seas at will. Submarines were equipped with weapons and communication devices. The submarine could stay at sea for months at a time and only required a few men to operate. They were small, quick, and hard to locate by larger ships. The submarine was thought to be the perfect naval vessel.
             The concept of the submarine dates back to Archimedes, the ancient mathematician, who "dreamed of building war vessels that could submerge at will and operate under the sea, so that they might sink the enemy without forewarning of their presence"(Bennett 265). A Dutchman named Cornelis Drebbel built the first successful submarine in 1620. Cornelis had designed a wooden submersible vehicle encased in leather. It was able to carry 12 rowers and a total of 20 men. Amazingly enough, the vessel could dive to the depth of 20 meters and travel 10-km. He conducted several series of trips below the surface of the Thames River, which lasted many hours. This early submarine was the first to address the problem of oxygen replenishment while submerged.
             In 1774, Thomas Day was one of those who lost their lives while trying to make the submarine dream a reality. The first use of the submarine in combat was in 1778 during the American Revolution when David Bushnell's "hand-propelled Turtle" was sent to attack the 64-gunned flagship, HMS Eagle. The Turtle had a one man crew operation. In 1790, Robert Fulton developed a submarine called the Plunger, which he tried to interest Napoleon Bonaparte in it's potential as a great naval investment. During the Civil War in the United States of America, the Confederate Hunley was dispatched and successfully sank the blockading Federal ships. At this time, three inventions were developed:
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