SSN-774 Virginia-class Batch 2 / Block III
Batch 2 Virginia class
The Navy planned to increase the combat power of the Virginia-class submarines by altering the way the boats are built and configured starting around 2012. The navy would change the design to contain a center section capable of housing various payloads and weapons that can be rapidly interchanged. The upgrades, which would be part of a "Batch 2 Virginia class", would occur starting in hull number 10 of a planned 30-boat program.
A family of payloads in various sizes would be developed for the SSGN, some of which will be retrofitted into the Virginia- and Los Angeles-class SSNs. Modular payload options for the Virginia class include: intelligence, surveillance, reconnaissance and target acquisition; special operations forces (SOF) support; strike weapons; undersea communications and sensor network systems; unmanned air vehicles (UAVs); and unmanned underwater vehicles (UUVs). Submarines are currently built with solid, integrated pressure vessels and weapons cells, obviating long and costly maintenance periods to carry out major changes. To create a boat capable of adapting quickly to individual missions, new submarines would be designed with a 'U-shaped' centre section that would allow various mission payloads to be removed quickly and inserted through the open part of the 'U'.
The Virginia-class submarines could include significant but classified propulsion plant innovations, with work starting on the nuclear Transformational Technology Core (TTC). At one time it seemed that the core could be ready as soon as 2010 - in time for the Batch 2 upgrades - and provide a 30-50% increase in energy output. The Transformational Technology Core reactor plant design was over 10% complete as scheduled in FY 2004.
Block III Virginia class
The VIRGINIA Class Program is structuring the next construction contract (Block III) as a Multi-Year Procurement of seven ships that will save the Navy $1.3 billion over the life of the contract. The Navy sought and obtained authority in the FY 2008 National Defense Authorization Act to enter into a Multi-Year Procurement (MYP) contract with Economic Order Quantity (EOQ) in FY 2009. This would provide the Navy a significant negotiating advantage, send a clear signal to industry regarding the Navy's commitment to future submarine procurement, and reduce risk. The Navy anticipates $2.9 billion (13%) of savings compared to annual (single ship) procurement contracts by using a 5-year/7-ship MYP contract for VIRGINIA Class submarines starting in FY 2009.
The design for affordability changes address some of the issues with the inherent and structural costs. The Navy is making an investment of about $600 million, primarily to fund design changes that will enable building the ships less expensively. That $600 million investment is driving a $3 billion reduction in the overall Virginia-Class Submarine Program. The highest priority is to reduce the cost of Virginia-Class submarines to a level that will support the procurement of two ships per year beginning in FY12.
The Design for Affordability initiative has four major aspects. The first relates to design changes to the vessel that will allow reducing the cost of buying components, and manufacturing and assembling the vessel. The second aspect would be a schedule reduction - shortening the time required to actually build the ship. That would also help avoid some of the peaks and valleys experienced in manning during the construction process. The third would be to increase efficiency on the waterfront, and the fourth would focus on the processes used to order and purchase materials. The Navy is encouraging the contractors to work closely to achieve progress in these areas and bring the cost of Virginia-class ships into the $2 billion range.
The program office will introduce a series of design changes beginning with the first Block III submarine, authorized for construction in 2008 [SSN-784]. Redesign could include anything from new lighting systems to replacing the front section of the submarine. The program office is also investigating replacing some hydraulic systems with lower-cost electric systems and simplifying other components like the propulsion lubrication system. Eventually the program office hopes to achieve savings of $100 million per submarine by 2012 through changes to technology and design.
Rear Adm. William Hilarides, the Navy's program executive officer for submarines, signaled the Block III redesign effort at an April 2006 press conference, when the Virginia subs were priced at $2.4 billion apiece. The goal is to cut the program's cost to about $2 billion per sub. The $2 billion figure is a baseline expressed in fiscal 2005 dollars. Adjusted for inflation, the actual amount will be higher when the Navy seeks funding for the ships. The figure was key to Navy hopes to begin building two subs per year starting in 2012.
Some capabilities -- such as the seven-man lockout chamber located amidships -- could be removed if other cost-reduction failed to do the job. Capability-reducing changes considered for the subs included deleting the lockout chamber and deleting or reducing the host ship capability for the Dry Deck Shelter and the Advanced SEAL Delivery System (ASDS). None of the capability-reducing changes had been incorporated as of 2007 and at that time plans retain all of these features. No reduction in combat or mission capability is expected from the changes.
The most impressive success was the "bow bundle". Designers are dramatically simplifying the bow, working to replace the traditional sonar sphere with a hydrophone array and change the configuration for the Tomahawk cruise missile launchers mounted behind the sphere. Instead of 12 individual tubes, the design would include two six-missile magazines. Not only will it save more than $40 million per ship, it will increase the payload flexibility of the Virginia class.
The new missile tubes are based on the 7-foot diameter D-5 Trident ballistic missile tubes, with changes similar to those done in the four Ohio-class SSGN submarine conversions. The tubes, which will be newly manufactured and somewhat shorter than the Ohio tubes, each carry a Multiple All-Up-Round Canister (MAC) with six Tomahawks. The Virginia installation omits the seventh missile in the center, leaving room for an access tube. The missile canister will be removable from the new Virginia Payload Tubes, allowing flexibility to fit different weapons or underwater vehicles. Since the connectors and dimensions are the same as the Ohio SSGN tubes, new payloads designed for those ships will be compatible with the Block III and later Virginias. The new tubes nearly double the amount of payload space compared with the former VLS installation, going from 1,200 cubic feet to 2,300. The new missile tubes will reduce construction and life-cycle costs, and save an estimated $8 million per ship beginning with the 2012 ship.
The new Large Aperture Bow (LAB) sonar array substitutes the sonar sphere active/passive transducers with a listening-only hydrophone system. Replacement of the water-backed LAB array for the air-backed sonar sphere will save about $11 million per sub. Much of the savings come from eliminating the hundreds of penetrations associated with the sphere. Electric Boat would no longer need to shape the spheres using a very expensive and sophisticated five-axis cutting machine. The LAB array features two primary components: the passive array - using hydrophone technology from the Seawolf SSN 21-class submarines - and a medium-frequency active array. The new hydrophones will last the planned 33-year life of the submarine, while the transducers will need replacement at about 17 years. While the sphere needed more than a thousand transducers each costing over $5,000, the LAB's 1,800 hydrophones cost about $600.
One example of an idea under development is the electrification of the Weapon Stowage and Handling module, which replaces hydraulic motors and control valves with electric motors and controllers. According to Project Manager Tom Polo this will eliminate hydraulic piping and valves on the weapons module, increase construction efficiency, and result in a $3.2M savings per ship. The electromechanical actuation system would not need, for example, the approximate 2,800 feet of hydraulic piping and about 2,000 welds required now and will take much less time to install. It also will reduce system maintenance, test time and mean time to repair. In 2007 schedules called for implementation on the SSN-785 in 2012.
Another major cost-reduction effort involves the way the submarines are built. Rather than building the subs in 10 modular sections - an effort shared equally by Electric Boat and Newport News - the modules are combined into four "super modules," all with a high degree of completion before being fitted together. The move is in line with worldwide industry trends. Shipyards building Navy ships are increasing the work done on modules before they're assembled into a full ship.
All the improvements mean the building time for the first Block III boat, New Hampshire [SSN-778], the next hull after the last Block II boat, North Carolina [SSN-777], will be cut by a year over the first ship. New Hampshire is expected to be delivered in 72 months - 14 months earlier than USS Hawaii [SSN-776], the most recent ship produced by Electric Boat. The Navy claims that it will be able to mitigate the shortage in forces by building the new Virginia class submarines faster by reducing the time between the start of construction to delivery from the current level of 86 months for the last boat to deliver to a level of 60 months.
The Navy is attempting to reduce cost in the Virginia-class submarine program by improving production processes. The program office seeks to reduce construction time by up to 24 months through improvements to construction efficiency. Some of the methods proposed include increasing the size and weight of the sections of the submarine while decreasing the number of sections produced, installing more equipment in the sections prior to assembling them, and performing hull treatments prior to delivery. These changes will be assisted by the construction of new, more efficient equipment and facilities at the shipyards, an initiative funded by the Navy and enabled by contract incentives. The Navy anticipates per-submarine savings of $65 million to $110 million through these initiatives, but acknowledges the significant increase in maturity of construction processes required to achieve these savings.
Reducing the construction start-to-delivery time would certainly speed the arrival of new construction boats in the fleet. However, on the whole SSN-688 class consisting of 62 boats, the contractors were only able to deliver three boats with a start-to-delivery interval of 60 months or less. The maximum building time was 86 months and the average for all 62 boats was 72 months.
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