page_title: Ohio-class submarine
section_title: Description
hierarchical_section_title: Ohio-class submarine / Description
caption_attribution_description: 021114-N-6497N-150 Naval Submarine Base, Bangor, Wash. (Nov. 14, 2002) -- Sailors complete the 200th drydocking maneuver of a Trident submarine at the Intermediate Maintenance Facility (IMF) Delta Pier. The strategic missile submarine USS Michigan (SSBN 727) is one of the Trident submarines that IMF has performed maintenance and a substantial level of overhaul work for which they recently celebrated their 20th anniversary.
context_page_description: The Ohio class of nuclear-powered submarines includes the United States Navy's 14 ballistic missile submarines and its four cruise missile submarines. Each displacing 18,750 tons submerged, the Ohio-class boats are the largest submarines ever built for the U.S. Navy. They are the world's third-largest submarines, behind the Russian Navy's Soviet-designed 48,000-ton Typhoon class and 24,000-ton Borei class. The Ohios carry more missiles than either: 24 Trident II missiles apiece, versus 16 by the Borei class and 20 by the Typhoon class.
  Like its predecessor Benjamin Franklin- and Lafayette-class subs, the Ohio SSBNs are part of the United States' nuclear-deterrent triad, along with U.S. Air Force strategic bombers and intercontinental ballistic missiles. The 14 SSBNs together carry about half of U.S. active strategic thermonuclear warheads. Although the Trident missiles have no preset targets when the submarines go on patrol, they can be given targets quickly, from the United States Strategic Command based in Nebraska, using secure and constant radio communications links, including very low frequency systems.
  The lead submarine of this class is USS Ohio.
context_section_description: The Ohio-class submarine was designed for extended strategic deterrent patrols. Each submarine is assigned two complete crews, called the Blue crew and the Gold crew, each typically serving 70-to-90-day deterrent patrols. To decrease the time in port for crew turnover and replenishment, three large logistics hatches have been installed to provide large-diameter resupply and repair access. These hatches allow rapid transfer of supply pallets, equipment replacement modules, and machinery components, speeding up replenishment and maintenance of the submarines. Moreover, the "stealth" ability of the submarines was significantly improved over all previous ballistic-missile subs.  Ohio was virtually undetectable in her sea trials in 1982, giving the U.S. Navy extremely advanced flexibility.
  The class's design allows the boat to operate for about 15 years between major overhauls. These submarines are reported to be as quiet at their cruising speed of 20 knots (37 km/h; 23 mph) or more than the previous Lafayette-class submarines at 6 knots (11 km/h; 6.9 mph), although exact information remains classified.  Fire control for their Mark 48 torpedoes is carried out by Mark 118 Mod 2 system, while the Missile Fire Control system is a Mark 98.
  The Ohio-class submarines were constructed from sections of hull, with each four-deck section being 42 ft (13 m) in diameter. The sections were produced at the General Dynamics Electric Boat facility, Quonset Point, Rhode Island, and then assembled at its shipyard at Groton, Connecticut.
  The US Navy has a total of 18 Ohio-class submarines which consist of 14 ballistic missile submarines (SSBNs), and four cruise missile submarines (SSGNs). The SSBN submarines provide the sea-based leg of the U.S. nuclear triad. Each SSBN submarine is armed with up to 24 Trident II submarine-launched ballistic missiles (SLBM). Each SSGN is capable of carrying 154 Tomahawk cruise missiles, plus a complement of Harpoon missiles to be fired through their torpedo tubes.
  As part of the New START treaty, four tubes on each SSBN will be deactivated, leaving each ship with only 20 available for war loads.
caption: USS Michigan (SSBN-727) at a dry-dock in November 2002, before its conversion to an SSGN.
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