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Seawolf-class submarine

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Seawolf class
The USS Seawolf (SSN-21) underway
Top: USS Seawolf (SSN-21) underway
Middle: Seawolf subgroup (boats 1 and 2) profile
Bottom: USS Jimmy Carter (boat 3) profile
Class overview
BuildersGeneral Dynamics Electric Boat
Operators United States Navy
Preceded byLos Angeles class
Succeeded byVirginia class
Cost$3 billion per unit (equivalent to $6 billion in 2023)[1]
In commission1997–present
General characteristics
TypeNuclear attack submarine
Beam40 ft (12 m)
  • 1 S6W PWR 220 MW (300,000 hp), HEU 93.5%[3][4]
  • 1 secondary propulsion submerged motor
  • 2 steam turbines 57,000 shp (43 MW) [4][5]
  • 1 shaft
  • 1 pump-jet propeller
  • 20 knots (23 mph; 37 km/h) (silent)[9]
  • 35 knots (40 mph; 65 km/h) (maximum)[9]
EnduranceOnly limited by food supplies
Test depth1,600 ft (490 m)[6]
Crew14 officers; 126 enlisted
Armament8 × 26.5-inch torpedo tubes, sleeved for 21-inch weapons[7] (up to 50 Tomahawk land attack missile/Harpoon anti-ship missile/Mk 48 guided torpedo carried in torpedo room)[8]

The Seawolf class is a class of nuclear-powered, fast attack submarines (SSN) in service with the United States Navy. The class was the intended successor to the Los Angeles class, and design work began in 1983.[10] A fleet of 29 submarines was to be built over a ten-year period, but that was reduced to 12 submarines. The end of the Cold War and budget constraints led to the cancellation of any further additions to the fleet in 1995, leaving the Seawolf class limited to just three boats. This, in turn, led to the design of the smaller Virginia class. The Seawolf class cost about $3 billion per unit ($3.5 billion for USS Jimmy Carter), making it the most expensive United States Navy fast attack submarine and second most expensive submarine ever, after the French Triomphant-class nuclear-powered ballistic missile submarines.


The Seawolf design was intended to combat the threat of advanced Soviet ballistic missile submarines such as the Typhoon class, and attack submarines such as the Akula class in a deep-ocean environment. Seawolf-class hulls are constructed from HY-100 steel, which is stronger than the HY-80 steel employed in previous classes, in order to withstand water pressure at greater depths.[11][12][self-published source]

Seawolf-class submarines are larger, faster, and significantly quieter than previous Los Angeles-class submarines; they also carry more weapons and have twice as many torpedo tubes. The boats are able to carry up to 50 UGM-109 Tomahawk cruise missiles for attacking land and sea surface targets. The boats also have extensive equipment to allow shallow water operations. The class uses the more advanced ARCI Modified AN/BSY-2 combat system, which includes a larger spherical sonar array, a wide aperture array (WAA), and a new towed-array sonar.[13] Each boat is powered by a single S6W nuclear reactor, delivering 45,000 hp (34 MW) to a low-noise pump-jet.

As a result of their advanced design, however, Seawolf-class submarines were much more expensive. The projected cost for 12 submarines of this class was $33.6 billion, but construction was stopped at three boats when the Cold War ended.[14]


USS Jimmy Carter is roughly 100 feet (30 m) longer than the other two boats of her class, due to the insertion of a section known as the Multi-Mission Platform (MMP) which allows launch and recovery of remotely operated underwater vehicles (ROV) and Navy SEALs.[15] The MMP may also be used as an underwater splicing chamber for tapping of undersea fiber optic cables. This role was formerly filled by the now decommissioned USS Parche. Jimmy Carter was modified for this role by General Dynamics Electric Boat at a cost of $887 million.[16]

Boats in class[edit]

Name Hull no. Builder Laid down Launched Commissioned Status
Seawolf subgroup
Seawolf SSN-21 General Dynamics Electric Boat, Groton 25 October 1989 24 June 1995 19 July 1997 Active in service
Connecticut SSN-22 14 September 1992 1 September 1997 11 December 1998 Active in service
Jimmy Carter subgroup
Jimmy Carter SSN-23 General Dynamics Electric Boat, Groton 5 December 1998 13 May 2004 19 February 2005 Active in service

See also[edit]


  1. ^ Trevithick, Joseph (22 October 2018). "Navy Wants New 'Seawolf-Like' Attack Submarines To Challenge Russian And Chinese Threats". Drive Media Inc. Retrieved 9 September 2019.
  2. ^ "The US Navy – Fact File". US Navy. Archived from the original on 3 July 2007. Retrieved 30 August 2008.
  3. ^ Alan Kuperman; Frank von Hippel (10 April 2020). "US study of reactor and fuel types to enable naval reactors to shift from HEU fuel". IPFM Blog.
  4. ^ a b "Validation of the Use of Low Enriched Uranium as a Replacement for Highly Enriched Uranium in US Submarine Reactors" (PDF). dspace.mit.edu. June 2015. p. 32. Retrieved 20 November 2021.
  5. ^ "S6W Advanced Fleet Reactor". www.globalsecurity.org. Retrieved 23 January 2023.
  6. ^ Federation of American Scientists (8 December 1998). "Run Silent, Run Deep". Military Analysis Network. Retrieved 10 May 2010.
  7. ^ Schank, John F.; Cesse, Cameron; Ip, Frank W.; Lacroix, Robert; Murphy, Mark V.; Arena, Kristy N.; Kamarck; Lee, Gordon T. (2011). "Learning from Experience: Volume II: Lessons from the U.S. Navy's Ohio, Seawolf, and Virginia Submarine Programs". rand.org.
  8. ^ "Attack Submarines - SSN". United States Navy Fact Files. United States Navy. Retrieved 13 November 2021.
  9. ^ a b "SSN Seawolf Class". naval-technology.com.
  10. ^ "Submarine Centennial Chronology". Archived from the original on 6 October 2012. Retrieved 22 December 2012.
  11. ^ Polmar, Norman (2004). The Naval Institute guide to the ships and aircraft of the U.S. fleet (18 ed.). Annapolis, Maryland: Naval Institute Press. pp. 81–82. ISBN 978-1-59114-685-8.
  12. ^ Zimmerman, Stan (2000). Submarine Technology for the 21st Century. Victoria, British Columbia: Trafford Publishing. p. 81. ISBN 978-1-55212-330-0.[self-published source]
  13. ^ "AN/BSY-2 sonar". www.harpoondatabases.com. Archived from the original on 6 October 2014. Retrieved 5 April 2018.
  14. ^ "SSN-21 Seawolf Class". Federation of American Scientists. Archived from the original on 19 April 2014. Retrieved 11 August 2011.
  15. ^ "USS Jimmy Carter (SSN-23)". Submarinehistory.com. Archived from the original on 3 July 2009. Retrieved 10 June 2009.
  16. ^ "Seawolf Class". General Dynamics Electric Boat. Archived from the original on 30 September 2011. Retrieved 5 August 2011.