Virginia-class submarine

The Virginia-class, also known as the SSN-774-class, is a class of nuclear-powered fast attack submarines (hull classification symbol SSN) in service with the United States Navy. The submarines are designed for a broad spectrum of open-ocean and littoral missions. They were conceived as a less expensive alternative to the Seawolf-class attack submarines, designed during the Cold War era, and they are planned to replace the older of the Los Angeles-class submarines, twenty of which have already been decommissioned (from a total of 62 built). The class was developed under the codename Centurion, renamed to NSSN (New SSN) later on. The "Centurion Study" was initiated in February 1991.

Innovations
The Virginia class incorporates several innovations not previously incorporated into other submarine classes.

Photonics masts
Instead of a traditional periscope, the class utilizes a pair of AN/BVS-1 telescoping photonics masts located outside the pressure hull. Each mast contains high-resolution cameras, along with light-intensification and infrared sensors, an infrared laser rangefinder, and an integrated Electronic Support Measures (ESM) array. Signals from the masts' sensors are transmitted through fiber optic data lines through signal processors to the control center. Visual feeds from the masts are displayed on LCD interfaces in the command center.

Propulsor
In contrast to a traditional bladed-propellor, the Virginia class uses pump-jet propulsors (built by BAE Systems), originally developed for the Royal Navy's Swiftsure class submarines. The propulsor significantly reduces the risks of cavitation, and allows quieter operation.

Improved sonar systems
Virginia class submarines are equipped with a bow-mounted spherical active/passive sonar array, a wide aperture lightweight fiber optic sonar array (three flat panels mounted low along either side of the hull), as well as two high frequency active sonars mounted in the sail and keel (under the bow). The submarines are also equipped with a low frequency towed sonar array and a high frequency towed sonar array. The chin-mounted (below the bow) high frequency sonar supplements the (spherical/LAB) main sonar array enabling safer operations in coastal waters as well as improving ASW performance.

The USS California (SSN-781) will be the first Virginia-class submarine with the advanced electromagnetic signature reduction system built into it, but this system will be retrofitted into the other submarines of the class.

Other improved equipment



 * Fiber optic fly-by-wire Ship Control System replaces electro-hydraulic systems for control surface actuation.


 * Command and control system module (CCSM) built by Lockheed Martin.


 * Modernized version of the AN/BSY-1 integrated combat system designated AN/BYG-1 (previously designated CCS Mk2) and built by General Dynamics AIS (previously Raytheon). AN/BYG-1 integrates the submarine Tactical Control System (TCS) and Weapon Control System (WCS).


 * Integral 9-man lock-out chamber.

History
Virginia class submarines were the first US Navy warships designed with the help of computer-aided design (CAD) and visualization technology. Around 9 million work hours are required for the completion of a single Virginia class submarine. Over 4,000 suppliers are involved in the construction of the Virginia class. Each submarine is projected to make 14-15 deployments during its 33-year service life.

The Virginias were intended, in part, as a cheaper ($1.8 billion vs $2.8 billion) alternative to the Seawolf class submarines, whose production run was stopped after just three boats had been completed. To reduce costs, the Virginia-class submarines use many "commercial off-the-shelf" (or COTS) components, especially in their computers and data networks. In practice, they actually cost less than $1.8 billion (in fiscal year 2009 dollars) each, due to improvements in shipbuilding technology.

In hearings before both House of Representatives and Senate committees, the Congressional Research Service (CRS) and expert witnesses testified that the current procurement plans of the Virginia class – one per year at present, accelerating to two per year beginning in 2012 – would result in high unit costs and (according to some of the witnesses and to some of the committee chairmen) an insufficient number of attack submarines. In a 10 March 2005 statement to the House Armed Services Committee, Ronald O'Rourke of the CRS testified that, assuming the production rate remains as planned, "production economies of scale for submarines would continue to remain limited or poor."

In 2001, Newport News Shipbuilding and General Dynamics Electric Boat Company built a quarter-scale version of a Virginia class submarine dubbed Large Scale Vehicle II (LSV II) Cutthroat. The vehicle was designed as an affordable test platform for new technologies.

The Virginia-class is built through an industrial arrangement designed to keep both GD Electric Boat and Newport News Shipbuilding and Drydock Company (the only two U.S. shipyards capable of building nuclear-powered vessels) in the submarine-building business. Under the present arrangement, the Newport News facility builds the stern, habitability and machinery spaces, torpedo room, sail and bow, while Electric Boat builds the engine room and control room. The facilities alternate work on the reactor plant as well as the final assembly, test, outfit and delivery.

O’Rourke wrote in 2004 that, "Compared to a one-yard strategy, approaches involving two yards may be more expensive but offer potential offsetting benefits." Among the claims of "offsetting benefits" that O'Rourke attributes to supporters of a two-facility construction arrangement is that it "would permit the United States to continue building submarines at one yard even if the other yard is rendered incapable of building submarines permanently or for a sustained period of time by a catastrophic event of some kind", including an enemy attack.

In order to get the submarine's price down to $2 billion per submarine in FY-05 dollars, the Navy instituted a cost-reduction program to shave off approximately $400 million in costs off each submarine's price tag. The project was dubbed "2 for 4 in 12," referring to the Navy's desire to buy two boats for $4 billion in FY-12. Under pressure from Congress, the Navy opted to start buying two boats a year earlier, in FY-11, meaning that officials would not be able to get the $2 billion price tag before the service started buying two submarines per year. However, program manager Dave Johnson said at a conference on 19 March 2008, that the program was only $30 million away from achieving the $2 billion price goal, and would reach that target on schedule.

The Virginia Class Program Office received the David Packard Excellence in Acquisition Award in 1996, 1998, 2008, "for excelling in four specific award criteria: reducing life-cycle costs; making the acquisition system more efficient, responsive, and timely; integrating defense with the commercial base and practices; and promoting continuous improvement of the acquisition process".

In December 2008, the Navy signed a $14 billion contract with General Dynamics and Northrop Grumman to supply eight submarines. The contractors will deliver one submarine in each of fiscal 2009 and 2010, and two submarines on each of fiscal 2011, 2012 and 2013. This contract will bring the Navy's Virginia-class fleet to 18 submarines. And in December 2010, the United States Congress passed a defense authorization bill that expanded production to two subs per year. Two submarine-per-year production resumed on 2 September 2011 with commencement of SSN-787 construction.

On 21 June 2008, the Navy christened the USS New Hampshire (SSN-778), the first Block II submarine. This boat was delivered eight months ahead of schedule and $54 million under budget. Block II boats are built in four sections, compared to the ten sections of the Block I boats. This enables a cost saving of about $300 million per boat, reducing the overall cost to $2 billion per boat and the construction of two new boats per year. Beginning in 2010, new submarines of this class will include a software system that can monitor and reduce their electromagnetic signatures when needed.

The first full duration six month deployment was successfully carried out from October 15, 2009 to April, 13, 2010. Authorization of full-rate production and the declaration of full operational capability was achieved five months later. In September 2010, it was found that urethane tiles, applied to the hull to damp internal sound and absorb rather than reflect sonar pulses, were falling off while the subs were at sea.

Professor Ross Babbage of the Australian National University has called on Australia to buy or lease a dozen Virginia class submarines from the United States, rather than locally build 12 replacements for its Collins class submarines.

In 2013, just as two per year sub construction was supposed to get started, Congress failed to resolve the United States fiscal cliff, forcing the Navy to attempt to "de-obligate" construction funds.

Technology barriers
Because of the low rate of Virginia production, the Navy entered into a program with DARPA to overcome technology barriers to lower the cost of attack submarines so that more could be built, to maintain the size of the fleet.

These include:


 * Propulsion concepts not constrained by a centerline shaft.
 * Externally stowed and launched weapons (especially torpedoes).
 * Conformal alternatives to the existing spherical sonar array.
 * Technologies that eliminate or substantially simplify existing submarine hull, mechanical and electrical systems.
 * Automation to reduce crew workload for standard tasks

Virginia Payload Module
Submarines built from 2019 onward will have an additional Virginia Payload Module (VPM) mid-body section, increasing their overall length. The VPM will add four large vertical launch tubes, located on the centerline, carrying up to seven Tomahawk missiles apiece, that would replace some of the capabilities lost when the SSGN conversion s are retired from the fleet. Initially eight payload tubes/silos were planned.

The VPM could potentially carry (non-nuclear) medium-range ballistic missiles. Adding the VPM would increase the cost of each submarine by $500 million (2012 prices). This additional cost would be offset by reducing the total submarine force by four ships. More recent reports state that as a cost reduction measure the VPM would carry only Tomahawk SLCM and possibly unmanned undersea vehicles (UUV) with the new price tag now estimated at $360-380 million per boat (in 2010 prices). The VPM launch tubes/silos will reportedly be similar in design to the ones planned for the Ohio class replacement. the CNO was still hoping to field the VPM from 2027, but deployment now seems unlikely since JROC moved the program in February 2013 from the Prompt Strike budget to the main Navy shipbuilding account, which is already under financial pressure.

Specifications



 * Builders: GD Electric Boat and HII Newport News
 * Length: 377 ft
 * Beam: 34 ft
 * Displacement: 7800 LT
 * Payload: 40 weapons, special operations forces, unmanned undersea vehicles, Advanced SEAL Delivery System (ASDS)
 * Propulsion: The S9G nuclear reactor, 29.8 MW delivering 40,000 shaft horse power. Nuclear core life estimated at 33 years.
 * Maximum diving depth: greater than 800 ft, allegedly around 1600 ft
 * Speed: Greater than 25 kn, allegedly up to 34 knots
 * Planned cost: about US$1.65 billion each (based on FY95 dollars, 30-ship class and two ship/year build-rate)
 * Actual cost: US$1.5 billion (in 1994 prices), US$2.6 billion (in 2012 prices)
 * Crew: 120 enlisted and 14 officers
 * Armament: 12 VLS & four torpedo tubes, capable of launching Mark 48 torpedoes, UGM-109 Tactical Tomahawks, Harpoon missiles and the new advanced mobile mine when it becomes available.
 * Decoys: Acoustic Device Countermeasure Mk 3/4

Block I
Modular construction techniques were incorporated during construction. Block I boats were built in 10 modules with each submarine requiring roughly 7 years (84 months) to build.
 * USS Virginia (SSN-774), commissioned and in service.
 * USS Texas (SSN-775), commissioned and in service.
 * USS Hawaii (SSN-776), commissioned and in service.
 * USS North Carolina (SSN-777), commissioned and in service.

Block II
Block II boats were built in four sections rather than ten sections, saving about $300 million per boat. Block II boats (excluding SSN-778) were also built under a multi-year procurement agreement as opposed to a block-buy contract in Block I, enabling savings in the range of $400 million ($80 million per boat). Improvements in the construction process also enabled shorter construction periods, for example, USS New Mexico (SSN-779) required one million fewer work hours to build than USS North Carolina (SSN-777).


 * USS New Hampshire (SSN-778), commissioned and in service.
 * USS New Mexico (SSN-779) commissioned and in service.
 * USS Missouri (SSN-780), commissioned and in service.
 * USS California (SSN-781), commissioned and in service.
 * USS Mississippi (SSN-782), commissioned and in service.
 * USS Minnesota (SSN-783), commissioned and in service.

Block III
USS North Dakota (SSN-784) through approximately SSN-791 are planned to make up the Third Block or "Flight" and began construction in 2009. Block III subs will feature a revised bow with a Large Aperture Bow (LAB) sonar array, as well as technology from Ohio-class SSGNs (2 VLS tubes each containing 6 missiles). The horseshoe-shaped LAB sonar array will replace the spherical main sonar array which has been used on all U.S. Navy SSNs since 1960.


 * USS North Dakota (SSN-784), named 15 July 2008, laid down 11 May 2012, will be christened in November 2013 and commissioned in May 2014.
 * USS John Warner (SSN-785), named 8 January 2009, laid down 16 March 2013, and is contracted for delivery in August 2015.


 * USS Illinois (SSN-786), construction has begun in March 2011.
 * USS Washington (SSN-787), named 13 April 2012, construction began on 2 Sep 2011.
 * USS Colorado (SSN-788)
 * USS Indiana (SSN-789)
 * USS South Dakota (SSN-790)
 * USS Delaware (SSN-791)

Block IV
No block IV submarines are yet under contract. The first block IV submarine is not scheduled to be procured until FY14. The long-lead-time materials contract for SSN 792 was awarded on April 17, 2012, with SSN 793 and SSN 794 following on December 28, 2012. the U.S. Navy has awarded General Dynamics Electric Boat a $208.6 million contract modification for the second fiscal year (FY) 14 Virginia-class submarine, SSN-793, and two FY 15 submarines, SSN-794 and SSN-795.With this modification, the overall contract is worth $595 million. Block IV will consist of 9-10 submarines. Based on the planned split between block IV and block V boats, the block IV procurement should comprise the following hull numbers.


 * SSN-792
 * SSN-793
 * SSN-794
 * SSN-795
 * SSN-796
 * SSN-797
 * SSN-798
 * SSN-799
 * SSN-800
 * SSN-801

Block V
Block V subs may incorporate the Virginia Payload Module (VPM), which would give guided-missile capability when the SSGNs are retired from service.
 * SSN-802
 * SSN-803
 * SSN-804

The Navy plans to acquire at least 30 Virginia class submarines, however, more recent data provided by the Naval Submarine League (in 2011) and the Congressional Budget Office (in 2012) seems to imply that more than 30 may eventually be built. The Naval Submarine League believes that up to 10 Block V boats will be built. The same source also states that 10 additional submarines could be built after Block V submarines, with 5 in the so-called Block VI and 5 in Block VII, largely due to the delays experienced with the "Improved Virginia". These 20 submarines (10 Block V, 5 Block VI, 5 Block VII) would carry VPM bringing the total number of Virginia class submarines to 48 (including the 28 submarines in Blocks I, II, III and IV). The CBO in its 2012 report states that 33 Virginia class submarines will be procured in the 2013-2032 timeframe, resulting in 49 submarines in total since 16 were already procured by the end of 2012. Such a long production run seems unlikely but it should be noted that another naval program, the Arleigh Burke class destroyer, is still ongoing even though the first vessel was procured in 1985. However, other sources believe that production will end with Block V. In addition, data provided in CBO reports tends to vary considerably compared to earlier editions.

In 2013 execution of a 10 submarine contract was put in doubt by Budget sequestration in 2013.

Improved Virginia
Initially dubbed Future Attack Submarine. Improved Virginia-class submarines will be an evolved version of the Virginia-class. It was planned that the first "Improved" Virginia-class submarine would be procured in 2025. However, according to some reports their introduction has been pushed back by eight years, to 2033.