The new BQQ-10 Acoustic Rapid Commercial Off The Shelf sonar will be fitted to all 55 attack submarines by 2007, giving them a more capable and standard system. With its open architecture and massive increase in processing power, this sonar can accommodate new software that previous systems could not handle.
Some submarines (starting with the Dallas) are being fitted with a Dry Deck Shelter that can carry SEAL delivery vehicles or raiding boats, expanding their capabilities. The third Seawolf (USS Jimmy Carter) will be 30m longer than the other two so that it can accommodate new technologies to support SEALS and other special functions. Four older Trident submarines are being rebuilt to carry conventional cruise missiles (seven missiles per tube, all 154 could be ripple fired in six minutes) with two of the former missile tubes turned into airlocks for SEALs. These four subs will carry 66 SEALs all the time and can accommodate 36 more in a "surge" situation. These modified submarines will include a command center where the SEALs can plan and command their missions and two Dry Dock Shelters.
The 154 missiles are a considerable force; an entire carrier battle group carries about the same number. One study has proposed mounting the new 127mm (five inch) advanced cannon in one of the missile tubes, allowing the sub (with decks awash) to fire precision-guided shells up to 100 miles. Another design study has proposed filling a missile tube with a "canister" loaded with Army multiple-launch (MLRS) rockets for shore bombardment.
While the US Navy today is half the size it was in 1989, the number of Intelligence, Surveillance, and Reconnaissance missions has doubled. Submarines are doing a lot of this work since they are faster than carrier groups, hard to detect (and often never detected), are invulnerable to the threats that aircraft carriers face (cruise missiles, ballistic missiles, chemical weapons), and have a wide range of capabilities. And the US is working overtime to give submarines new capabilities. Manned minis subs to deliver SEAL commandoes have been around for decades, but now unmanned mini-subs are in development to conduct recon missions. New weapons are being researched that could disable a ship (or submarine) without sinking it, allowing the enforcement of blockades and sanctions with fewer casualties.
Other weapons considered for both Virginia and other submarines are underwater rockets (like the Russian Skval), laser and microwave weapons, and a device that could produce a shock wave strong enough to detonate mines.
The new Virginia-class nuclear submarine will have the capabilities of the Seawolf, but with a lower cost. Thirty will be bought to replace the Los Angeles class. Virginia is the first class designed to accommodate SEALS as a regular complement of the crew rather than as an afterthought. It includes an airlock able to handle nine frogmen at one time, as well as a Dry Dock Shelter and the Advanced SEAL Delivery System. The Virginias will be subjected to a "spiral increment" design system, where 25 major improvements are added over time to newly-built and earlier submarines. One of the periscopes on Virginia may be replaced by a 25mm M242 Chaingun carried on an extendable mast, allowing the submarine to engage helicopters or small surface craft while submerged at periscope depth.
Virginia will have an integrated electrical system, with reactor output channeled into a common power grid that could be tapped for various sensors or weapons as needed. By using a power grid rather than a physical drive shaft, designers can position equipment around the submarine in better locations. By using power and fiber-optic cables to link sections of the submarine instead of physical pipes and shafts, later refits will be faster to install.
Electric Boat is already designing the next submarine after Virginia. In a break with US designs, it will have a full-length double hull, with the pressure hull entirely inside a free-flooding outer hull. It will be 98 meters long (compared to 115 meters for Virginia) but will displace 8,600 tons (compared to Virginia's 7,830 tons). This has rows of missile tubes in the space between the hulls.
The Navy is also studying the "behemoth", a huge double-hulled submarine that is 156m long, 12.8m in diameter, and displacing 10,200 tons. It could carry 280 weapons (torpedoes or missiles) that fit in its 21-inch tubes. Double-hulled designs allow designers to build a cylindrical pressure hull (the least expensive and strongest) while shaping the outer hull for the best travel through the water. The space between the hulls can be used to dampen the sound from the machinery inside the pressure hull.
Designs for unmanned underwater vehicles are getting sophisticated, leading to the Multi Purpose Unmanned Underwater Vehicle. This can be stored inside the submarine, reconfigured with modular sensors or weapons or other payloads, and fueled for its mission, then recovered after it completes the assigned task. With extra fuel in its modular cells, it could conduct a recon mission of up to 200 nautical miles. The MPUUV could even carry relatively cheap and short-ranged bombardment missiles to saturate a target after longer-ranged Tomahawks have wrecked its defenses.--Stephen V Cole