.jpg) The plannedColumbia-class submarine, as drawn in 2019 by Naval Sea Systems Command | |
| Class overview | |
|---|---|
| Preceded by | Ohio class (ballistic missile submarine variant) |
| Cost | |
| Built | 2020–present |
| Planned | 12 |
| On order | 1 |
| Building | 2 |
| General characteristics | |
| Type | Nuclear-poweredballistic missile submarine (SSBN) |
| Displacement | 20,810 long tons (21,140 t) (submerged)[2] |
| Length | 560 ft (171 m)[2] |
| Beam | 43 ft (13 m)[2] |
| Installed power | S1B[3] |
| Propulsion | Turbo-electric drive,pump-jet[2] |
| Range | Unlimited |
| Complement | 155 (accommodation)[2] |
| Sensors & processing systems | Enlarged version of theVirginia-class LAB sonar[2] |
| Armament | 16 ×Trident D5[4] andtorpedo tubes |
The upcomingColumbia class (formerly known as theOhio Replacement Submarine andSSBN-X Future Follow-on Submarine) arenuclear-poweredballistic missile submarines of theUnited States Navy, designed to replace theOhio class.[5] Construction of the first vessel began on 1 October 2020,[6] and is scheduled to enter service in 2031.[7][8][9]
On 3 June 2022, the Navy announced that the lead vessel of the class will be namedUSS District of Columbia (SSBN-826), because there is already anattack submarine namedUSS Columbia (SSN-771).[10] Nevertheless, the Navy has since continued to refer to the class asColumbia.[11][12]
TheColumbia class is to replace theOhio class of ballistic missile submarines, whose remaining boats are to be decommissioned, one per year, beginning in 2028.[citation needed] TheColumbia class will take over the role of submarine presence in the United States'strategic nuclear force.[4]
Electric Boat designed the new class with help fromNewport News Shipbuilding. A total of twelve submarines are planned,[13] and construction of the lead boat began in 2021. Each submarine will have sixteen missile tubes, each carrying oneUGM-133 Trident II D5LE missile.[citation needed] (The ninth and laterColumbias are to receive the upgraded D5LE2s.)[14][15] The submarines will be 560 feet (170.7 m) long and 43 feet (13.1 m) in diameter, as long as theOhio-class design, and 1 foot (30 cm) larger in diameter.[4]
To determine how many submarines would be needed for the U.S. strategic nuclear force, Navy planners calculated how many missiles would be needed at sea and on station at any given time, how many each submarine should carry, and the likelihood that a submarine will remain undiscovered by the enemy and be able to launch. They also explored how required maintenance would affect availability.[16] Cost-reduction studies explored design and construction possibilities, including adding missile tubes to the design of theVirginia-classattack submarine, buildingOhio-class replacement submarines using updatedOhio-class designs, and developing an entirely newOhio Replacement Submarine design.[4][17]
The Navy concluded that a new design would be the least expensive option that could meet all of the technical requirements.[16] For example, while the modifiedVirginia-class and updatedOhio-class design options would have required an expensive mid-life refueling,[4] eachColumbia-class nuclear core will last as long as the submarine is in service.[18][19]
The design and technology development of theColumbia class is projected to cost $4.2 billion (fiscal 2010 dollars), with technology and components from theOhio andVirginia classes included where possible to save money.[citation needed] The cost to buildDistrict ofColumbia, thelead boat of the class, will be an estimated $6.2 billion (fiscal 2010 dollars).[4] The Navy has a goal of reducing the average cost of the remaining eleven planned hulls in the class to $4.9 billion each (fiscal 2010 dollars).[18] The total lifecycle cost of the entire class is estimated at $347 billion.[18] The high cost of the submarines is expected to cut deeply into Navy shipbuilding.[20]
In April 2014, the Navy completed a 300-page specification report for theOhio Replacement Program submarines. There are 159 specifications including weapons, escape routes, fluid systems, hatches, doors, seawater systems, and a set length of 560 ft (170 m), partly to allow for sufficient volume inside the pressure hull.[21]
In March 2016, the U.S. Navy chose General Dynamics Electric Boat as the prime contractor and lead design yard.[22] Electric Boat, which built all eighteenOhio-class submarines,[23] will do most of the work on all twelveColumbia boats, including final assembly.[24] Huntington Ingalls Industries' Newport News Shipbuilding will serve as the main subcontractor, participating in the design and construction and doing 22 to 23 percent of the work.[25]
In late 2016, some 3,000 Electric Boat employees were involved in the detailed-design phase of the program[26] and the procurement of the first submarine was scheduled for 2021.[4] Completion of the first submarine was scheduled for 2030, followed by its entry into service in 2031. All twelve submarines are expected to be completed by 2042 and remain in service until 2085.[4][21]
On 28 July 2016, it was reported that the first submarine of the class will be namedColumbia, to commemorate theDistrict of Columbia, the capital of the United States.[27] TheColumbia class was officially designated on 14 December 2016 by Secretary of the NavyRay Mabus, and the lead submarine will beUSS District of Columbia (SSBN-826).[28] The Navy wanted to procure the firstColumbia-class boat in FY2021.[29]
On 28 October 2020, U.S. Navy SecretaryKenneth J. Braithwaite announced that the second submarine would be namedUSS Wisconsin (SSBN-827), after theU.S. state of the same name.[30]
On 7 June 2021, the U.S. Navy budget office announced that the total cost forDistrict of Columbia would reach $15.03 billion, which includes planning costs for the entire program.[31] As of April 2023, the estimated construction cost of the twelve-boat program is $132 billion. Securing the supply chain and maintaining a skilled labor force are two major challenges for the program.[32]
Although still evolving, the following are some of the characteristics for the SSBN(X) design:[8][33]
The U.S. Navy has also said that "owing to the unique demands of strategic relevance, SSBN(X)s must be fitted with the most up-to-date capabilities and stealth to ensure they are survivable throughout their full 40-year life span."[4]
In November 2012, the U.S. Naval Institute, citingNaval Sea Systems Command, revealed additional design information:[37]
TheColumbia-class submarine may also be equipped with a Submarine Warfare Federated Tactical System (SWFTS), a cluster of systems that integrate sonar, optical imaging, weapons control etc.[38][39][40]
In a bid to reduce life-cycle cost andacoustic signature,[41][42]Columbia is to run on electric drive—that is, it will use an electric motor to turn its propellers instead of the reduction gearing and mechanical drive systems used on earlier nuclear-powered submarines.[43][44] It will retain the nuclear reactor andsteam turbines typical of U.S. Navy submarines. In such systems, the nuclear reactor heats water to steam, the turbines convert the heat in the steam into mechanical energy, and the generators convert that mechanical energy into electrical energy[45] for use by the propulsion motors and other onboard systems.[46][47]
Turbo-electric drives were successfully used on U.S. battleships and aircraft carriers in the first half of the 20th century,[48] and on the small nuclear-powered submarineUSS Tullibee in the late 1950s.[49] Another larger nuclear-powered submarine,USS Glenard P. Lipscomb, was equipped with a turboelectric drive but proved to be underpowered, unreliable, and maintenance-hungry.[50][51] As of 2013[update], the only operational turboelectric-powered subs were the French Navy'sTriomphant-class submarines.[52]
In 2014,Northrop Grumman was chosen as the prime designer and manufacturer ofColumbia's turbine generator units.[46] That same yearLeonardo DRS was selected as the main propulsion motor and propulsion motor drive provider. The lead ship motor was delivered to Electric Boat in August 2022.[53]
Various types of electric motors have and are being developed for military and non-military vessels.[54] Types being considered for future U.S. submarines include permanent magnet motors (PMM) being developed byGeneral Dynamics and Newport News Shipbuilding, and high-temperature superconducting synchronous motors, being developed by American Superconductors andGeneral Atomics.[54][55][56] More recent[when?] data shows that the U.S. Navy appears to be focusing on permanent-magnet, radial-gap electric propulsion motors.[citation needed] TheZumwalt-class destroyer design switched from PMM to an advanced induction motor.[57] In 2013, permanent magnet motors were tested on theLarge Scale Vehicle II for possible application on late-productionVirginia-class submarines, as well as future submarines.[58][59] Siemens AG PMMs are used onType 212 submarines in service with theGerman andItalian navies.[60]
TheRoyal Navy'sDreadnought-class submarine, which is to replace theVanguard class of ballistic missile submarines, may have submarine shaftless drive (SSD) with an electric motor mounted outside the pressure hull.[61][unreliable source?] SSD was evaluated by the U.S. Navy, but it remains unknown whether theColumbia class will have it.[62][63] On contemporary nuclear submarines, steam turbines are linked to reduction gears and a shaft rotating the propeller/pump-jet propulsor. With SSD, steam would drive electric turbogenerators, powered by steam turbines, that would be connected to a non-penetrating electric junction at the aft end of the pressure hull, with a watertight electric motor mounted externally, possibly an Integrated Motor Propulsor arrangement,[64] powering the pump-jet propulsor,[61] although SSD concepts without pump-jet propulsors also exist.[65] In 2015, anOhio-Replacement scale model at the Navy League's 2015 Sea-Air-Space Exposition suggested that the sub would have a pump-jet propulsor visually similar to the one used onVirginia class[66][37] perhaps as part of the Navy's stated desire to reuseVirginia components to reduce risk and cost of construction.[66][4]
In December 2008, General Dynamics Electric Boat Corporation was selected to design the Common Missile Compartment that will be used on theOhio-class successor.[35] In 2012, the U.S. Navy announced plans for its SSBN(X) to share a common missile compartment (CMC) design with the Royal Navy'sDreadnought-class ballistic missile submarine.[4] The CMC will house SLBMs in "quad packs".[67][68]
| Name | Hull Number | Builder | Ordered | Laid down | Launched | Commissioned | Homeport | Status |
|---|---|---|---|---|---|---|---|---|
| USSDistrict of Columbia | SSBN-826 | General Dynamics Electric Boat,Groton, CT | 5 November 2020[69] | 4 June 2022[69][70] | Under construction[69] | |||
| USSWisconsin | SSBN-827 | 5 November 2020[71] | 27 August 2025[72] | Under construction | ||||
| USSGroton[73] | SSBN-828 |
