Virginia-class submarine

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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 Virginia-class attack submarine is the U.S. Navy's newest undersea warfare platform and incorporates the latest in stealth, intelligence gathering and weapons systems technology. Attack submarines are designed to seek and destroy enemy submarines and surface ships as well as project power ashore with Tomahawk cruise missiles and Special Operation Forces, carry out Intelligence, Surveillance, and Reconnaissance (ISR) missions; support carrier battle group operations; and engage in naval mine warfare.

Virginia-class submarines are designed for a broad spectrum of open-ocean and littoral (shallow coastal water) missions. They are replacing older Los Angeles-class submarines, many of which have already been decommissioned. The Seawolf-class attack submarine was originally intended to succeed the Los Angeles-class, but production was canceled after only three submarines were produced due to budgeting restraints at the end of the Cold War, and the final submarine was manufactured in 1995. Virginia-class submarines will be acquired through 2043, and are expected to remain in service past 2060. Based on recent updates to the designs, some of the Virginia-class submarines are expected to still be in service in 2070.

Video Virginia-class submarine

History

The class was developed under the codename Centurion, renamed to New SSN (NSSN) later on. The "Centurion Study" was initiated in February 1991. Virginia-class submarines were the first US Navy warships designed with the help of computer-aided design (CAD) and visualization technology. By 2007 approximately 35 million labor hours were spent on designing the Virginia class. Around 9 million labor hours are required to construct 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 Virginia-class was intended in part as a less expensive alternative to the Seawolf-class submarines ($1.8 billion vs $2.8 billion), 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" (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 procurement plans of the Virginia class - one per year, accelerating to two per year beginning in 2012 - would result in high unit costs and an insufficient number of attack submarines, according to some of the witnesses and the committee chairman. In a 10 March 2005 statement to the House Armed Services Committee, Ronald O'Rourke of the CRS testified that, assuming that 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 (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 of 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 per year 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 Washington (SSN-787) construction.

On 21 June 2008, the Navy christened USS New Hampshire, 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 15 October 2009 to 13 April 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. Admiral Kevin McCoy announced that the problems with the Mold-in-Place Special Hull Treatment for the early subs had been fixed in 2011, then Minnesota was built and found to have the same problem.

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 commence, Congress failed to resolve the United States fiscal cliff, forcing the Navy to attempt to "de-obligate" construction funds.

Maps Virginia-class submarine

Innovations

The Virginia-class incorporates several innovations not found in previous US submarine classes.

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

Unified Modular Masts

For the first time in history the design of the eight masts in the Virginia class has been unified in a Universal Modular Mast (UMM) program led by L3 KEO (previously Kollmorgen): shared components have been maximized and some design choices are also shared between different masts. The first UMM was first installed on USS Memphis, a Los Angeles-class submarine. The UMM is an integrated system for housing, erecting, and supporting submarine mast-mounted antennas and sensors. The UMMs are:

• Snorkel mast
• Two photonic masts
• Two (tactical) communication masts
• One or two high-data-rate satellite communication (SATCOM) masts, built by Raytheon, enabling communication at Super High Frequency (for downlink) and Extremely High Frequency (for uplink) range
• Radar mast (carrying AN/BPS-16 surface search and navigation radar)
• Electronic warfare mast (AN/BLQ-10 Electronic Support Measures) used to detect, analyze, and identify both radar and communication signals from ships, aircraft, submarines, and land-based transmitters

Photonics masts

The Virginia class is the first to utilize photonic sensors instead of a traditional periscope. The class is equipped with high-resolution cameras, along with light-intensification and infrared sensors, an infrared laser rangefinder, and an integrated Electronic Support Measures (ESM) array. Two redundant sets of these sensors are mounted on two AN/BVS-1 photonics masts located outside the pressure hull. Signals from the masts' sensors are transmitted through optical fiber data lines through signal processors to the control center. Visual feeds from the masts are displayed on liquid-crystal display interfaces in the command center.

The design of earlier optical periscopes required them to penetrate the pressure hull, reducing the structural integrity of the pressure hull as well as increasing the risk of flooding, and also required the submarine's control room to be located directly below the sail/fin. Implementation of photonics masts (which do not penetrate the pressure hull) enabled the submarine control room to be relocated to a position inside the pressure hull which is not necessarily directly below the sail.

The current photonics masts have a visual appearance so different from the ordinary periscopes that when the submarine is detected, it can be distinctly identified as a Virginia-class vessel. As a result, current photonic masts will be replaced with Low-Profile Photonics Masts (LPPM) which resemble traditional submarine periscopes more closely.

In the future, a non-rotational Affordable Modular Panoramic Photonics Mast may be fitted, enabling the submarine to obtain a simultaneous 360° view of the sea surface.

Propulsor

In contrast to a traditional bladed propeller, 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

Sonar arrays aboard Virginia-class submarines have an "Open System Architecture" (OSA) which enables rapid insertion of new hardware and software as they become available. Hardware upgrades (dubbed Technology Insertions) are usually carried out every four years, while software updates (dubbed Advanced Processor Builds) are carried out every two years. Virginia-class submarines feature several types of sonar arrays.

• BQQ-10 bow-mounted spherical active/passive sonar array (Large Aperture Bow (LAB) sonar array from SSN-784 onwards)
• A wide aperture lightweight fiber optic sonar array, consisting of three flat panels mounted low along either side of the hull
• Two high frequency active sonars mounted in the sail and bow. The chin-mounted (below the bow) and sail-mounted high frequency sonars supplement the (spherical/LAB) main sonar array, enabling safer operations in coastal waters, enhancing under-ice navigation, and improving anti-submarine warfare performance.

• Low-Cost Conformal Array (LCCA) high frequency sonar, mounted on both sides of the submarine's sail. Provides coverage above and behind the submarine.

Virginia-class submarines are also equipped with a low frequency towed sonar array and a high frequency towed sonar array.

• TB-16 or TB-34 fat line tactical towed sonar array
• TB-29 or TB-33 thin line long-range search towed sonar array

Rescue equipment

• Submarine Escape Immersion Equipment MK11 suit(s) - enable ascent from a sunken submarine (maximum ascent depth 600 feet)
• lithium hydroxide canisters that remove carbon dioxide from the submarine's atmosphere
• Submarine Emergency Position Indicating Radio Beacon (SEPIRB)

Virginia Payload Module

The Block III submarines have two multipurpose Virginia Payload Tubes (VPT) replacing the dozen single purpose cruise missile launch tubes.

The Block V 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 more VPTs of the same diameter and greater height, located on the centerline, carrying up to seven Tomahawk missiles apiece, that would replace some of the capabilities lost when the SSGN conversion Ohio-class submarines are retired from the fleet. Initially eight payload tubes/silos were planned but this was later rejected in favour of 4 tubes installed in a 70-foot long module between the operations compartment and the propulsion spaces.

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 boats. 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. In July 2016 General Dynamics was awarded $19 million for VPM development. In February 2017 General Dynamics was awarded $126 million for long lead time construction of Block V submarines equipped with VPM.

The VPM was designed by BWX Technologies (the same company also designs the missile tubes for the Columbia-class submarine), however, manufacture is undertaken by BAE Systems.

Other improved equipment

• Optical fiber fly-by-wire Ship Control System replaces electro-hydraulic systems for control surface actuation.
• Command and control system module (CCSM) built by Lockheed Martin.
• The auxiliary generator is powered by a Caterpillar model 3512B V-12 marine diesel engine. This replaced the Fairbanks-Morse diesel engine, which would not fit in Virginia's auxiliary machinery room.
• 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).
• USS California was the first Virginia-class submarine with the advanced electromagnetic signature reduction system built into it, but this system is being retrofitted into the other submarines of the class.

• Integral 9-man lock-out chamber.

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Specifications

• Builders: GD Electric Boat and HII Newport News Shipbuilding
• Length: 377 ft (114.91 m)
• Beam: 34 ft (10.36 m)
• Displacement: 7,800 long tons (7,900 t)
• Payload: 40 weapons, special operations forces, unmanned undersea vehicles, Advanced SEAL Delivery System (ASDS)
• Propulsion: The S9G nuclear reactor delivering 40,000 shaft horse power. Nuclear core life estimated at 33 years. Nuclear fuel manufactured by BWX Technologies.
• Test depth: greater than 800 ft (240 m), allegedly around 1,600 feet (490 m).
• Speed: Greater than 25 knots (46 km/h; 29 mph), allegedly up to 35 knots (65 km/h; 40 mph)
• Planned cost: about US$1.65 billion each (based on FY95 dollars, 30-boat class and two boat/year build-rate)
• Actual cost: US$1.5 billion (in 1994 prices), US$2.6 billion (in 2012 prices)
• Annual operating cost: $50 million per unit
• Crew: 120 enlisted and 14 officers
• Armament: 12 VLS & four torpedo tubes, capable of launching Mark 48 torpedoes, UGM-109 Tactical Tomahawks, Harpoon (missile)s and the new advanced mobile mine when it becomes available. Block V boats will have the additional VPM module which contains four large diameter tubes which can accommodate 7 Tomahawk cruise missiles each. This would increase the total number of torpedo-sized weapons (such as Tomahawks) carried by the Virginia class design from about 37 to about 65--an increase of about 76%.
• Decoys: Acoustic Device Countermeasure Mk 3/4

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Boats

Block I

(4 boats) Modular construction techniques were incorporated during construction. Earlier submarines (e.g., Los Angeles-class SSNs) were built by assembling the pressure hull and then installing the equipment via cavities in the pressure hull. This required extensive construction activities within the narrow confines of the pressure hull which was time-consuming and dangerous. Modular construction was implemented in an effort to overcome these problems and make the construction process more efficient. Modular construction techniques incorporated during construction include constructing large segments of equipment outside the hull. These segments (dubbed rafts) are then inserted into a hull section (a large segment of the pressure hull). The integrated raft and hull section form a module which, when joined with other modules, forms a Virginia-class submarine. Block I boats were built in 10 modules with each submarine requiring roughly 7 years (84 months) to build.

Block II

(6 boats) 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). As a result of improvements in the construction process, New Hampshire was 500 million USD cheaper, required 3.7 million fewer labor hours to build (25% less), thus shortening the construction period by 15 months (20% less) compared to Virginia.

Block III

(8 boats) SSN-784 through SSN-791 make up the Third Block or "Flight" and began construction in 2009. Block III subs 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 replaces the spherical main sonar array which has been used on all U.S. Navy SSNs since 1960. The LAB sonar array is water-backed--as opposed to earlier sonar arrays which were air-backed--and consists of a passive array and a medium-frequency active array. Compared to earlier Virginia-class submarines about 40% of the bow has been redesigned.

South Dakota (SSN-790) will be equipped with a new propulsor, possibly the Hybrid Multi-Material Rotor (HMMR), developed by Defense Advanced Research Projects Agency (DARPA). The Hybrid Multi-Material Rotor program is an attempt to improve the design and manufacturing process of submarine propellers with an aim of reducing the cost and weight of the propeller/rotor as well as improving overall acoustic performance.

Block IV

(10 boats) In 2013 execution of a 10-submarine contract was put in doubt by Budget sequestration in 2013. The most costly shipbuilding contract in history was awarded on 28 April 2014 as prime contractor General Dynamics Electric Boat took on a $17.6 billion contract for ten Block IV Virginia-class attack submarines. The main improvement over the Block III is the reduction of major maintenance periods from four to three, increasing each ship's total lifetime deployments by one.

The long-lead-time materials contract for SSN-792 was awarded on 17 April 2012, with SSN-793 and SSN-794 following on 28 December 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 consists of 10 submarines and comprises the following hull numbers.

Block V

(10 boats) Block V subs may incorporate the Virginia Payload Module (VPM), which would give guided-missile capability when the SSGNs are retired from service. The Block V subs are expected to triple the capacity of shore targets for each boat. Construction on the first two boats of this block is expected to begin in 2019, with contracts for SSN-802 and SSN-803 being awarded to General Dynamic's Electric Boat. HII Newport News Shipbuilding was awarded a long-lead materials contract for two Block V boats in 2017, the first Block Vs for the company.

Future acquisitions

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.

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SSN(X)/Improved Virginia

Initially dubbed Future Attack Submarine and Improved Virginia class in Congressional Budget Office (CBO) reports, the SSN(X) or Improved Virginia-class submarines will be an evolved version of the Virginia class.

In late 2014, the Navy began early preparation work on the SSN(X). It was planned that the first submarine would be procured in 2025. However, their introduction (i.e., procurement of the first submarine) has been pushed back to 2033/2034. The long-range shipbuilding plan is for the new SSN to be authorized in 2034, and become operational by 2044 after the last Block VII Virginia is built. Roughly a decade will be spent identifying, designing, and demonstrating new technologies before an analysis of alternatives is issued in 2024. An initial small team has been formed to consult with industry and identify the threat environment and technologies the submarine will need to operate against in the 2050-plus timeframe. One area already identified is the need to integrate with off-board systems so future Virginia boats and the SSN(X) can employ networked, extremely long-ranged weapons. A torpedo propulsion system concept from the Pennsylvania State University could allow a torpedo to hit a target 200 nmi (230 mi; 370 km) away and be guided by another asset during the terminal phase. Targeting information might also come from another platform like a patrol aircraft or an unmanned aerial vehicle (UAV) launched from the submarine. Researchers have identified a quieter advanced propulsion system and the ability to control multiple unmanned underwater vehicles (UUVs) at once as key SSN(X) components. The future submarines will operate through the end of the 21st century, and potentially into the 22nd century. New propulsion technology, moving beyond the use of a rotating mechanical device to push the boat through the water, could come in the form a biomimetic propulsion system that would eliminate noise-generating moving parts like the drive shaft and the spinning blades of the propulsor.

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See also

• List of submarine classes of the United States Navy
• List of submarines of the United States Navy
• List of submarine classes in service
• Submarines in the United States Navy
• Cruise missile submarine
• Attack submarine
• List of current United States Navy ships

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References

Notes

Citations

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Further reading

• Clancy, Tom (2002). Submarine: A Guided Tour Inside A Nuclear Warship. New York: Berkley Books. ISBN 0-425-18300-9. OCLC 48749330. 
• Christley, J. L. (2000). United States Naval Submarine Force Information Book. Marblehead, Massachusetts: Graphic Enterprises of Marblehead. OCLC 53364278. 
• Christley, Jim (2007). US Nuclear Submarines: The Fast Attack. Oxford, UK. ISBN 1-84603-168-0. OCLC 141383046. 
• Cross, Wilbur; Feise, George W. (2003). Encyclopedia of American Submarines. New York: Facts on File. ISBN 0-8160-4460-0. OCLC 48131805. 
• Gresham, John; Westwell, Ian (2004). Seapower. Edison, New Jersey: Chartwell Books. ISBN 0-7858-1792-1. OCLC 56578494. 
• Holian, Thomas (Winter 2007). "Voices from Virginia: Early Impressions from a First-in-Class". Undersea Warfare. 9 (2). 
• Johnson, Dave, CAPT; Muniz, Dustin, LTJG (Winter 2007). "More for Less: The Navy's Plan to Reduce Costs on Virginia-class Submarines While Increasing Production". Undersea Warfare. 9 (2). 
• Little, Molly (Summer 2008). "The Elements of Virginia". Undersea Warfare Magazine (38).  Updates on the boats of the Virginia-class
• Little, Molly (Summer 2008). "A Snapshot of the Virginia-class With Rear Adm. (sel.) Dave Johnson". Undersea Warfare (38).  Q&A on the Virginia-class program since the Winter 2007 article
• Parker, John (2007). The World Encyclopedia of Submarines. London: Lorenz. ISBN 0-7548-1707-5. OCLC 75713655. 
• Polmar, Norman (2001). The Naval Institute Guide to the Ships and Aircraft of the U.S. Fleet. Annapolis, Maryland: Naval Institute Press. ISBN 1-55750-656-6. OCLC 47105698. 
• "The Virginia Class Submarine Program". Fort Belvoir, Virginia: Defense Standardization Program Office. 2007. OCLC 427536804. 

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External links

• Naval History & Heritage Command
• VIRGINIA CLASS ATTACK SUBMARINE - SSN
• Stealth, Endurance, and Agility Under the Sea
• Virginia Class Submarines Some U.S. Navy Photos of Virginia Class Submarines
• Submarine Industrial Base Resources Information about the Submarine Industrial Base

Source of article : Wikipedia