Ohio-class submarine

Ohio-class submarine
USS Michigan (SSBN-727) at a drydock, in November 2002, prior to conversion to SSGN.
Class overview
Name: Ohio class
Builders: General Dynamics Electric Boat[1]
Operators:  United States Navy[1]
Preceded by: Benjamin Franklin class
Succeeded by: Columbia class[2]
Built: 1976–1997
In commission: 1981–present
Planned: 24
Completed: 18
Cancelled: 6
Active: 18
General characteristics
Type: SSBN/SSGN (hull design SCB-304)[3]
  • 16,764 tonnes (16,499 long tons) surfaced[1][4]
  • 18,750 tonnes (18,450 long tons) submerged[1]
Length: 560 ft (170 m)[1]
Beam: 42 ft (13 m)[1]
Draft: 35.5 ft (10.8 m) maximum[5]
  • 12 knots (22 km/h; 14 mph) surfaced[1]
  • 20 knots (37 km/h; 23 mph) submerged (official)[1]
  • 25 knots (46 km/h; 29 mph) submerged (reported)[1]
Range: Limited only by food supplies
Test depth: +800 ft (240 m)
Complement: 15 officers, 140 enlisted[1][4]
Sensors and
processing systems:
  • BQQ-6 passive bow-mounted array[1] (which includes BQS-13 fire control array)[6]
  • BQR-19 navigation[1]
  • TB-16[1] or BQR-23 towed array[6]
  • BQR-25 conformal array[6]
Armament: 4 × 21 in (53 cm) Mark 48 torpedo tubes (Forward Compartment 4th level)
General characteristics SSBN-726 to SSBN-733 from construction to refueling
Armament: 24 × Trident I C4 SLBM with up to 8 MIRVed 100 ktTNT W76 nuclear warheads each, range 4,000 nmi (7,400 km; 4,600 mi)
General characteristics SSBN-734 and subsequent hulls upon construction, SSBN-730 to SSBN-733 since refueling
Armament: 24 × Trident II D5 SLBM with up to 12 MIRVed W76 or W88 (300–475 ktTNT) nuclear warheads each, range 6,100 nmi (11,300 km; 7,000 mi)
General characteristics SSGN conversion
Armament: 22 tubes, each with 7 Tomahawk cruise missiles, totaling 154

The Ohio class is a class of nuclear-powered submarines currently used by the United States Navy. The navy has 18 Ohio-class submarines: 14 ballistic missile submarines (SSBN) and four that were later converted to guided missile submarines (SSGN).

The Ohio class is named after the lead submarine of this class, USS Ohio. The 14 Trident II SSBNs together carry approximately fifty percent of the total US active inventory of strategic thermonuclear warheads. Although the Trident missiles have no pre-set targets when the submarines go on patrol, the warships, when required, are capable of quickly being assigned targets by using secure and constant radio communications links at sea, including very low frequency (VLF) systems.

All the Ohio-class submarines, except for USS Henry M. Jackson, are named for U.S. states, which until that point was a tradition reserved for battleships and cruisers.

The Ohio-class submarines are the largest submarines ever built for the U.S. Navy. Two classes of the Russian Navy's submarines have larger total displacements: the Soviet-designed Typhoon-class submarines have more than twice the total displacement, and Russia's Borei-class submarines have roughly 25 percent greater displacement, but the Ohio-class boats carry more missiles than either: 24 Trident missiles per boat, versus 16 missiles for the Borei class (20 for the Borei II) and 20 for the Typhoon class.


The Ohio-class submarines were designed specifically for extended war-deterrence patrols. Each of these submarines is provided with two complete crews, called the Blue crew and the Gold crew, with each crew serving typically on 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, significantly reducing the time required for replenishment and maintenance of the submarines.

Longitudinal cross-section diagram of Ohio-class submarines

The class's design allows the warship to operate for about fifteen 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,[6] while the Missile Fire Control (MFC) system is a Mark 98.[6]

The Ohio-class submarines were constructed from sections of hull, with each four-deck section being 42 ft (13 m) in diameter.[5][6] The sections were produced at the General Dynamics Electric Boat facility, Quonset Point, Rhode Island, and then assembled at its shipyard at Groton, Connecticut.[5]

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 are also known as "Trident" submarines, and 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.


See also: STRAT-X

The first eight Ohio-class submarines were armed at first with 24 Trident I C4 SLBMs.[5] Beginning with the ninth Trident submarine, Tennessee, the remaining boats were equipped with the larger, three-stage Trident II D5 missile.[6] The Trident I missile carries eight multiple independently targetable reentry vehicles (MIRV), while the Trident II missile carries twelve, in total delivering more destructive power than the Trident I missile and with greater accuracy. Starting with Alaska in 2000, the Navy began converting its remaining ballistic missile submarines armed with C4 missiles to carry D5 missiles. This task was completed in mid-2008.

The first eight submarines had their home ports at Bangor, Washington, to replace the submarines carrying the Polaris A3 missile that were then being decommissioned. The remaining ten submarines originally had their home ports at Kings Bay, Georgia, replacing the Poseidon and Trident Backfit submarines of the Atlantic Fleet. During the conversion of the first four submarines to SSGNs (see below), five of the submarines, Pennsylvania, Kentucky, Nebraska, Maine, and Louisiana, were transferred from Kings Bay to Bangor. Further transfers occur as the strategic weapons goals of the United States change.

In 2011, Ohio-class submarines carried out 28 deterrent patrols. Each patrol lasts around 70 days. Four boats are on station ("hard alert") in designated patrol areas at any given time.[7] From January to June 2014, Pennsylvania carried out a 140-day-long patrol, the longest to date.[8]

SSBN/SSGN conversions

After the end of the Cold War, plans called for Ohio to be retired in 2002, followed by three of her sister boats. However, Ohio, Michigan, Florida, and Georgia instead were slated for modification, to remain in service carrying conventionally armed guided missiles, and were redesignated as SSGNs.

The conversion modified 22 of the 24 88-inch (2.2 m) diameter Trident missile tubes to contain large vertical launch systems (VLS), one configuration of which may be a cluster of seven Tomahawk cruise missiles. In this configuration, the number of cruise missiles carried could be a maximum of 154, the equivalent of what is typically deployed in a surface battle group. Other payload possibilities include new generations of supersonic and hypersonic cruise missiles, and Submarine Launched Intermediate Range Ballistic Missiles (SLIRBM),[9] unmanned aerial vehicles (UAVs), the ADM-160 MALD, sensors for anti-submarine warfare or intelligence, surveillance, and reconnaissance missions, countermine warfare payloads such as the AN/BLQ-11 Long Term Mine Reconnaissance System (LMRS), and the broaching universal buoyant launcher (BUBL) and stealthy affordable capsule system (SACS) specialized payload canisters.

Black submarine with orange paint from cheatline down in drydock at nightfall.
USS Ohio being converted from an SSBN to an SSGN in March 2004.

The missile tubes also have room for stowage canisters that can extend the forward deployment time for special forces. The other two Trident tubes are converted to swimmer lockout chambers. For special operations, the Advanced SEAL Delivery System and the dry deck shelter can be mounted on the lockout chamber and the boat will be able to host up to 66 special operations sailors or Marines, such as Navy SEALs, or USMC MARSOC teams. Improved communications equipment installed during the upgrade allows the SSGNs to serve as a forward-deployed, clandestine Small Combatant Joint Command Center.[10]

On 26 September 2002, the Navy awarded the Electric Boat company a US$442.9 million contract to begin the first phase of the SSGN submarine conversion program. Those funds covered only the initial phase of conversion for the first two boats on the schedule. Advanced procurement was funded at $355 million in fiscal year 2002, $825 million in the FY 2003 budget and, through the five-year defense budget plan, at $936 million in FY 2004, $505 million in FY 2005, and $170 million in FY 2006. Thus, the total cost to refit the four boats is just under $700 million per vessel.

The helm of the Ohio-class guided-missile submarine, USS Florida (SSGN-728), in March 2010.

In November 2002, Ohio entered a drydock, beginning her 36-month refueling and missile conversion overhaul. Electric Boat announced on 9 January 2006 that the conversion had been completed. The converted Ohio rejoined the fleet in February 2006, followed by Florida in April 2006. The converted Michigan was delivered in November 2006. The converted Ohio went to sea for the first time in October 2007. Georgia returned to the fleet in March 2008 at Kings Bay.[11] These four SSGNs are expected to remain in service until about 2023–2026. At that point their capabilities will be replaced with Virginia Payload Module equipped Virginia-class submarines.[12]


The U.S. Department of Defense anticipates a continued need for a sea-based strategic nuclear force.[13] The first of the current Ohio SSBNs are expected to be retired by 2029,[13] meaning that a platform must already be seaworthy by that time. A replacement may cost over $4 billion per unit compared to Ohio's $2 billion.[4] The U.S. Navy is exploring two options. The first is a variant of the Virginia-class nuclear-powered attack submarines. The second is a dedicated SSBN, either with a new hull or based on an overhaul of the current Ohio.

With the cooperation of both Electric Boat and Newport News Shipbuilding, in 2007, the U.S. Navy began a cost control study.[13] Then in December 2008 the U.S. Navy awarded Electric Boat a contract for the missile compartment design of the Ohio-class replacement, worth up to $592 million. Newport News is expected to receive close to 4% of that project. The U.S. Navy has yet to confirm an Ohio-class replacement program. However, in April 2009, U.S. Defense Secretary Robert M. Gates confirmed that the U.S. Navy should begin such a program in 2010.[4] The new vessel is scheduled to enter the design phase by 2014. It is anticipated that, if a new hull design is used, the program must be initiated by 2016 in order to meet the 2029 deadline.[13]

Artist's concept of an Ohio-class SSGN launching Tomahawk Land Attack Missiles.

As ballistic missile submarines, the Ohio class has occasionally been portrayed in fiction books and films.

See also


  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 "Ohio-class SSGN-726 Overview". Federation of American Scientists. Retrieved 2011-09-27.
  2. "New U.S. Navy Nuclear Sub Class to Be Named for D.C.". 28 July 2016.
  3. Adcock, Al. (1993). U.S. Ballistic Missile Submarines. Carrolltown, Texas: Squadron Signal. pp. 4, 40. ISBN 978-0-89747-293-7.
  4. 1 2 3 4 Frost, Peter. "Newport News contract awarded". Daily Press. Retrieved 2011-09-27. (subscription required (help)).
  5. 1 2 3 4 5 6 Adcock, Al (1993). U.S. Ballistic Missile Submarines. Carrolltown, Texas: Squadron Signal. p. 40. ISBN 978-0-89747-293-7.
  6. 1 2 3 4 5 6 7 Adcock, Al (1993). U.S. Ballistic Missile Submarines. Carrolltown, Texas: Squadron Signal. p. 41. ISBN 978-0-89747-293-7.
  7. Kristensen, Hans M. (December 2012). "Trimming Nuclear Excess: Options for Further Reductions of U.S. and Russian Nuclear Forces Special Report No 5" (pdf). Federation of American Scientists.
  8. Arendes, Ahron (30 June 2014). "USS Pennsylvania Sets Patrol Record". Military.com.
  9. "Submarine Launched Intermediate Range Ballistic Missile". Global Security. Retrieved 2011-09-27.
  10. "USS Ohio Returns To Service As Navy's First SSGN" (PDF). Electric Boat News (Newsletter). General Dynamics Electric Boat. February 2006. Archived from the original (pdf) on 2009-07-31.
  11. "Navy Marks USS Georgia's Return To Service". CBS 4 News Jacksonville. Retrieved 2008-12-03.
  12. O'Rourke, Ronald (1 March 2012). "CRS-RL32418 Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress". Open CRS. Congressional Research Service. Retrieved 2012-11-21.
  13. 1 2 3 4 "SSBN-X Future Follow-on Submarine". Global Security. Retrieved 2011-09-27.
  14. http://www.usnavymuseum.org/pdf/teacher_help-10.pdf
  15. "Crimson Tide". Internet Movie Database. Retrieved 2011-09-27.
  16. "Last Resort Co-Creator Explains Submarine Story Development". The Dead Bolt. 27 September 2012. Retrieved 2011-09-27.

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