Virginia-class submarine


The Virginia class, also known as the SSN-774 class, is a class of nuclear-powered cruise missile fast-attack submarines, currently in military service in the United States Navy. Designed by General Dynamics's Electric Boat and Huntington Ingalls Industries, the Virginia-class submarines are the United States Navy's latest undersea warfare platform which incorporates the latest in stealth, intelligence gathering and weapons systems technology.
Virginia-class submarines are designed for a broad spectrum of open-ocean and littoral missions, including anti-submarine warfare and intelligence gathering operations. They are scheduled to replace older s, many of which have already been decommissioned. Virginia-class submarines will be acquired through 2043, and are expected to remain in service until at least 2060, with later submarines expected to remain into the 2070s.

History

The class was developed under the codename Centurion, later renamed to New SSN. The "Centurion Study" was initiated in February 1991. Virginia-class submarines were the first US Navy warships designed with the help of the computer-aided design and visualization technology CATIA. Due to programming limitations however, this led to design issues for Electric Boat and maintenance problems for the Navy.
By 2007 approximately 35 million labor hours had been 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, 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" components, especially in their computers and data networks. In practice, they actually cost less than $1.8 billion each, due to improvements in shipbuilding technology.
In hearings before both House of Representatives and Senate committees, the Congressional Research Service 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 Cutthroat. The vehicle was designed as an affordable test platform for new technologies.
The Virginia class is built through an industrial arrangement designed to maintain both GD Electric Boat and Newport News Shipbuilding, the only two U.S. shipyards capable of building nuclear-powered submarines. Under the present arrangement, the Newport News facility builds the stern, habitability, 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 contract required the delivery of one submarine in each of fiscal 2009 and 2010, and two submarines on each of fiscal 2011, 2012, and 2013. This contract was designed to bring the Navy's Virginia-class fleet to 18 submarines. 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 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 s.
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.

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:
Virginia class subs are the first class where all masts share common design - the Universal Modular Mast - designed by L3 KEO. Shared components have been maximized and some design choices are also shared between different masts. The first UMM was installed on, 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 the following.
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 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 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 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, originally developed for the Royal Navy's s. The propulsor significantly reduces the risks of cavitation, and allows quieter operation.

Improved sonar systems

arrays aboard Virginia-class submarines have an "Open System Architecture" which enables rapid insertion of new hardware and software as they become available. Hardware upgrades are usually carried out every four years, while software updates are carried out every two years. Virginia-class submarines feature several types of sonar arrays.
Virginia-class submarines are also equipped with a low frequency towed sonar array and a high frequency towed sonar array.
The Block III submarines have two multipurpose Virginia Payload Tubes replacing the dozen single purpose cruise missile launch tubes.
The Block V submarines built from 2019 onward will have an additional Virginia Payload Module 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 s are retired from the fleet. Initially eight payload tubes/silos were planned but this was later rejected in favour of four tubes installed in a long module between the operations compartment and the propulsion spaces.
The VPM could potentially carry medium-range ballistic missiles. Adding the VPM would increase the cost of each submarine by $500 million. 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 with the new price tag now estimated at $360–380 million per boat. 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, however, manufacture is undertaken by BAE Systems.

High-energy laser weapon

According to open-source budget documents, Virginia-class submarines are planned to be equipped with a high-energy laser weapon likely to be incorporated into the photonics mast and have a power output of 300–500 kilowatts, based on the submarine's 30 megawatts reactor capacity.

Other improved equipment

Block I

Block I involved 4 boats and modular construction techniques were incorporated during construction. Earlier submarines 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 are then inserted into a hull section. 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 to build.

Block II

Block II involved 6 boats; they were built in four sections rather than ten sections, saving about $300 million per boat. Block II boats 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. As a result of improvements in the construction process, New Hampshire was US$500 million cheaper, required 3.7 million fewer labor hours to build, thus shortening the construction period by 15 months compared to Virginia.

Block III

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 sonar array, as well as technology from Ohio-class SSGNs. 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 will be equipped with a new propulsor, possibly the Hybrid Multi-Material Rotor, developed by Defense Advanced Research Projects Agency. 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

Block IV involved 10 boats. In 2013, execution of this 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 boat'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 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.

Block V

Block V involves 10 boats and may incorporate the Virginia Payload Module, 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 was expected to begin in 2019 but was pushed back to 2020, with contracts for long lead time material 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.
On 2 December 2019, the Navy announced an order for nine new Virginia-class submarines - eight Block Vs and one Block IV - for a total contract price of $22 billion with an option for a tenth boat. The Block V subs were confirmed to have an increased length, from 377 ft to 460 ft, and displacement, from 7,800 tons to 10,200 tons. This would make the Block V the second-largest US submarine, behind only the Ohio-class.

List of boats

Future acquisitions

The Navy plans to acquire at least 30 Virginia-class submarines, however, more recent data provided by the Naval Submarine League and the Congressional Budget Office seems to imply that more than 30 submarines 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 would carry VPM bringing the total number of Virginia-class submarines to 48. 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 another naval program, the, 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.

SSN(X)/Improved ''Virginia''

Initially dubbed Future Attack Submarine and Improved Virginia class in Congressional Budget Office reports, the SSN 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. It was planned that the first submarine would be procured in 2025. However, their introduction 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 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 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 launched from the submarine. Researchers have identified a quieter advanced propulsion system and the ability to control multiple unmanned underwater vehicles at once as key SSN 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.