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SSN-21 Seawolf-class

Seawolf-class submarines were designed to operate autonomously against the world's most capable submarine and surface threats. The primary mission of the Seawolf was to destroy Soviet ballistic missile submariness before they could attack American targets. The Soviet submarines are one of the most survivable elements of their intercontinental ballistic missile arsenal. In addition to their capabilities in countering enemy submarines and surface shipping, Seawolf submarines are suited for battlespace-preparation roles. Incorporation of sophisticated electronics produces enhanced indications and warning, surveillance, and communications capabilities. These platforms are capable of integrating into a battle group's infrastructure, or shifting rapidly into a land-battle support role.

The Seawolf features a strengthened sail, designed to permit operations under the polar ice cap for taking the fight to the Soviets in their own front yard. It sports an eight-tube, double-deck torpedo room to simultaneously engage multiple threats. It incorporates the latest in quieting technology to keep pace with the threat then posed by an aggressive Soviet Union.

The Seawolf has the highest tactical speed of any US submarine. Much much of the design effort was focused on noise reduction, and it is expected that the fully coated boat will restore the level of acoustic advantage which the US Navy enjoyed for the last three decades. The Seawolf's propulsion system makes it ten times more quiet over its full range of operating speeds than the Improved-688 class and 70 times more quiet than the initial generation of Los Angeles 688-class submarines. The Seawolf's quieter propulsion system will also enable it to have twice the tactical speed as the I-688. Tactical speed is the speed at which a submarine is still quiet enough to remain undetected while tracking enemy submarines effectively. Overall, the Seawolf's propulsion system represents a 75-percent improvement over the I-688's -- the Seawolf can operate 75 percent faster before being detected. It is said that SEAWOLF is quieter at its tactical speed of 25 knots than a LOS ANGELES-class submarine at pierside.

The AN/BSY-2 Submarine Combat System is designed to support SSN 21 in all mission areas. It detects, classifies, localizes and tracks targets, platforms, and weapons by means of onboard active and passive sensors and with augmented target information from other platforms and external detection systems. The combat control subsystem provides setting and control of weapons, over-the-horizon targeting, combat systems management, improved target motion analysis, piloting and navigation functions, and automatic contact correlation. It includes the weapon launch equipment for the Mark 48 Advanced Capability Torpedo and the Tomahawk Missile. Acoustic hardware includes a truncated 24 ft diameter spherical receive array, a 15 ft diameter hemisphere active transmit array, a wide aperture array, a low frequency bow array, two towed arrays, and a mine detection and avoidance high frequency array.

With twice as many torpedo tubes and a 30% increase in weapons magazine size over the Los Angeles (SSN 688)-class submarines, Seawolf is capable of establishing and maintaining battlespace dominance. Seawolf's inherent stealth enables surreptitious insertion of combat swimmers into denied areas. SSN 23 will incorporate special-operations force capabilities, including a dry deck shelter (DDS) and a new, specially designed combat swimmer silo. The DDS is an air-transportable device that piggy-backs on the submarine and can be used to store and launch a swimmer delivery vehicle and combat swimmers. The silo is an internal lock-out chamber that will deploy up to eight combat swimmers and their equipment at one time.

The submarines are constructed from hull sections built in a factory at Quonset Point, RI. A hull section is a cross-sectional piece of the ship, approximately 25-40 feet long. A hull section consists of welded-together cylinders with diameters of their respective parts of the ship, up to about 40 feet. While still in the factory, these sections are outfitted with almost all of the items that go into that part of the submarine; they are very crowded. This in-factory, modular manufacturing is much more efficient than outfitting the ship after welding the sections together in the shipyard, as was done in the past. One complication in modular manufacturing: pipes and cables span multiple hull sections, some running nearly the length of the ship's interior. The approximately 1000-ton, 90+-percent-populated hull sections are then shipped on barges to the shipyard in Groton, CT, where they are welded together, assembled, and finished.

Construction of the submarine has relied on a new welding material to join the steel into plates, hull subsections and large cylindrical sections. The Seawolf is the first American attack submarine to use a hull made entirely of high-pressure HY-100 steel -- previous sumarines used HY80 steel. HY-100 steel was first used in submarines in the early 1960s in the Navy's deep-diving SEA CLIFF and TURTLE,, which were capable of reaching depths in excess of 10,000 feet. More recently, the Moray, an advanced conventional submarine designed by the Dutch shipyard R.D.M. (Rotterdamsche Droogdok Maatschappij B.V), incorporated HY-100 steel to achieve an operational diving depth of 300 meters, and an incidental diving depth of 360 meters.

The SEAWOLF program began in the mid-1980s to ensure U.S. submarine superiority over Soviet counterparts well into the next century. The first U.S. attack submarine in decades designed from the keel up to accommodate the latest weapons, sensors, propulsion, and communication advancements, SEAWOLF exceeded expectations during lead ship sea trials in the summer of 1996. The test program included first underwater submergence, acoustics trials, engineering inspections and at-sea training for the crew. Seawolf (SSN 21) was commissioned on 19 July 1997 at Electric Boat Shipyard.

Seawolf was projected to be the most expensive ever built, with a total program cost for 12 submarines estimated in 1991 at $33.6 billion in current dollars. As many as 29 submarines were planned. The Navy's plans for Seawolf would have resulted in spending 25 percent of the Navy's shipbuilding budget on a ship that was designed for threats that vanished with the end of the Cold War. In the 1992 State of the Union address, President Bush [and Defense Secretary Dick Cheney] proposed the rescission of $2,765,900,000 previously appropriated for the procurement of the second and third Seawolfs. Two Seawolf Class submarines were authorized by Congress, which in 1995 agreed to terminate the program at three boats. President Clinton endorsed the construction of SSN-23 as the most cost-effective method of retaining the vitality of the submarine industrial base while bridging the gap to the future New Attack Submarine. The Fiscal Year 1998 $153.4 million budget request was the final increment of funding required for the third SEAWOLF to complete the program. The program continues to be managed within the Congressionally mandated cost cap.

Overall, the reduction in the class of ships from an original projection of thirty total to three total coupled with potentially incomplete allowance computation models to create logistics support challenges for Seawolf. Those challenges were addressed in various ways, including the cannibalization of Prospective Commissioning Unit (PCU) Jimmy Carter (SSN 23) to support the two operational units. But, this proved a costly and risky proposition.

As of 1998 the $7.4 billion cost limitation for the Seawolf Program appeared to be adequate. Of the $745.4 million of obligated canceled ship funds, the Navy obligated $557.6 million in design costs, termination costs, and program support costs that did not result in components that the Navy could use in the construction of the Seawolf class submarines. The costs should not be applied against the cost limitation. The Navy obligated the remaining $187.8 million for construction spares. The Navy planned to use $28.4 million of the $187.8 million for hull, mechanical, and electrical components in constructing the SSN-23 submarine. Because the cost limitation imposed on the Seawolf program applies to ship construction funds used to construct the SSN-21, SSN-22, and SSN-23 submarines, the Navy should apply the $28.4 million for SSN-23 submarine construction spares against the cost limitation. If the Navy uses any of the remaining $159.4 million in construction spares for construction of the Seawolf submarines, then it should apply those costs against the cost limitation; otherwise it should not apply those costs against the cost limitation.

The Navy performed two estimates-at-completion for the Seawolf program. Both the Seawolf Program Management Office and the Seawolf Independent Cost Review Team develop an estimate-at-completion. The Seawolf Program Management Office estimate-at-completion is $7,393 million, the Seawolf Independent Cost Review Team estimate is $67.3 million less at $7,325.7 million. The Navy has only requested additional funds for allowable escalation and post-delivery and outfitting costs. The Seawolf Program Management Office's budget submission for FY 1999 included $50 million in escalation. In addition, the budget submission included $30 million for recovery of FY 1996 and 1997 congressionally directed reductions in budgeted funding levels to cover other priorities outside the Seawolf program. The Seawolf program had not experienced cost growth in the Shipbuilding and Conversion-Navy funding levels since Congress established the $7.2 billion cost limitation in FY 1996.

Although several requirement thresholds were not met, DOT&E evaluated the Seawolf Class Nuclear Attack Submarine and the BSY-2 Submarine Combat Control System as operationally effective and operationally suitable. Details of USS Seawolf's performance during OPEVAL are available in the classified OT&E/LFT&E Report. The Seawolf and the BSY-2 Combat Control System were adequately tested to assess operational effectiveness and suitability, but the lack of a full ship shock trial prevented full assessment of Seawolf's survivability. However, the Seawolf design incorporates numerous features that improve survivability over previous classes. These features make Seawolf less susceptible and vulnerable and thus, considered more survivable than the Los Angeles class submarine.

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Page last modified: 07-07-2011 12:54:41 ZULU