|
|
|
|
|
|
Submarines |
|
|
Submarine, type of warship designed to operate completely underwater for long periods of time. They are designed to submerge and surface, and to maneuver quietly underwater to avoid detection. Submarines can launch a variety of weapons including torpedoes, mines, antiship and land-attack cruise missiles, and submarine launched ballistic missiles (SLBMs) with nuclear warheads. Modern submarines have a cylindrical hull that tapers at one end and forms a blunt, rounded nose at the other end. They are usually made of high-quality steel but may also be made out of titanium. Most modern submarines are powered by nuclear energy, though some rely on diesel engines and electric batteries for propulsion. Photo in the News: Crashed U.S. Nuclear Submarine
February 1, 2005—The U.S. Navy released this photograph last Thursday of the nuclear submarine San Francisco, which crashed headlong into an uncharted undersea mountain near Guam on January 8. Standing more than three stories high and with classified technology veiled by a tarp, the fast-attack submarine is shown awaiting repairs in a Guam dry dock. The impact shredded the submarine's nose, killed one sailor, and injured 60 more. The sailors were largely protected by the vessel's reinforced inner hull, which did not rupture. After the wreck, the crew quickly ascended and sailed along the ocean's surface back to their base in Guam. Modern Nuclear Submarine:
Modern submarines are an important part of a country’s military forces. Attack submarines, like the USS Asheville shown here, are primarily used to hunt other submarines or surface warships. They can also fire at land targets with cruise missiles. Submarine design and complexity have evolved considerably since the first efforts to build submarines over 500 years ago. Accounts of pre-industrial submarines of the 1500s describe small oar-propelled wooden boats covered in treated leather, which would allow them to travel at or just below the water’s surface for short distances. In contrast, the nuclear attack submarine USS Seawolf is 107.6 m (353 ft) long, made of steel, and is armed with a variety of weapons. The USS Seawolf has a crew of 130, and can travel around the world completely submerged at depths in excess of 460 m (1500 ft). The use of submarines in warfare has evolved steadily with improvements in their diving ability, underwater endurance, and weapons technology. Submarines of the 1700s and early 1800s were larger in size than their predecessors, but were still primitive hand-powered ships, with rudimentary and often ineffective explosive weapons. Periscopes, which enabled submariners to view the surface waters while remaining shallowly submerged, were added to submarines in the mid-1800s. By the outbreak of World War I (1914-1918), most industrialized countries had acquired a first generation fleet of crude but effective diesel-electric submarines. World War II (1939-1945) submarines improved upon these designs with better engines and longer ranges. Nuclear power, first introduced into a submarine in 1954, extended the range of a submarine even more. Nuclear-powered submarines can stay submerged for longer periods than diesel subs, since nuclear engines don’t need to surface for oxygen. 
Crew members of submarine Vladivostok gather on the deck of the ship for a rare moment in open air. Named after an important naval base founded by the Russians in 1860, the ship spends most of its time underwater during patrols and other missions. Although a crew member may spend sixty days beneath the surface at a time, modern submarines are well air-conditioned and usually have libraries and game rooms to relieve monotony. Submarines are valued for their ability to roam undetected in the ocean, and many navies operate submarine fleets. In the 1950s, when international tensions between the United States and the Union of Soviet Socialist Republics (USSR) were at their peak, there was a maximum of about 650 submarines of all types among the major powers. Since the collapse of the USSR in 1991, the number of advanced submarines in the world has shrunk considerably. In the late 1990s, five countries—the United States, Russia, the United Kingdom, France, and China—continued to operate a total of about 150 advanced submarines, most of them nuclear-powered. Several other countries continue to operate older, less sophisticated submarines. |
|
|
|
|
|
|
|
|
|
|
|
|