Submarine

Submarine, ship capable of sustained underwater operation. The first working craft, built by the Dutch inventor Cornelis Drebbel (1620), was a wooden rowboat covered with greased leather that could remain submerged for as long as 15 hours. The first submarine used in warfare, designed by David Bushnell of the United States (1776), was a one-man, hand-powered, screwdriven vessel designed to attach mines to enemy ships. In the Civil War the Confederate states produced several submarines. Later (late 1800s and early 1900s) John P. Holland and his rival Simon Lake designed vessels powered by gasoline engines on the surface and by electric motors when submerged. The forerunners of modern submarines, they were armed with torpedoes and guns. Great advances were made during World War I and World War II. German U-boats introduced snorkels to hinder detection while recharging batteries. The first nuclear-powered submarine was the USS Nautilus (1955), which made the first voyage under the polar ice-cap (1958). Modern submarines are streamlined vessels, generally with a double hull, the inner one a pressure hull separated from the outer one by fuel and ballast tanks. The submarine submerges by flooding the ballast tanks to displace its own weight of water. It uses hydrofoil diving planes. Besides their military applications, submarines are used for oceanographic research and exploration, salvage, and rescue.