History of submarines few years before the US, and paralleled subsequent US development in this area. In the 1950s, nuclear power partially replaced diesel-electric propulsion. The sailing of the first nuclear-powered submarine, the USN ""Nautilus"" in 1955 was soon followed by similar British, French and Russian boats. Equipment was also developed to extract oxygen from sea water. These two innovations, together with inertial navigation systems, gave submarines the ability to remain submerged for weeks or months, and enabled previously impossible voyages such as the crossing of the North Pole beneath the Arctic ice cap by the USS "Nautilus" in 1958. Most of the
Sail (submarine) Sail (submarine) In naval parlance, the sail (American usage) or fin (European/Commonwealth usage) of a submarine is the tower-like structure found on the dorsal (topside) surface of submarines. Submarine sails once housed the conning tower (command and communications data center), the periscope(s), radar and communications masts (antenna), though most of these functions have now been relocated to the hull proper (and so the sail is no longer considered a "conning tower"). In the US Navy, the structure is frequently called a fairwater, and diving planes mounted on it are called fairwater planes. When above the water's surface, the sail serves