First Advanced SEAL Delivery System Sub Accepted by Navy Despite Development Problems, Critics

On 26 June, the US Navy took delivery of the US Special Operations Command’s (USSOCOM) Advanced SEAL Delivery System (ASDS), during a ceremony at Northrop Grumman Oceanic and Naval Systems in Annapolis. This not withstanding, talk of problems dogs the new system.

As reported previously in The Nav Log, the US Navy is converting four older Trident-class ballistic missile submarines for 21st century duty as guided missile subs (SSGNs) and vessels to support littoral warfare. One if the new features of these subs is as a carrier of dedicated SEAL teams, complete with their own small special ops submarine, carried piggyback upon the host sub. The boat was designed and developed by a team composed of Northrop Grumman's Oceanic & Naval Systems business unit, NAVSEA, USSOCOM and Naval Special Warfare Command.

Currently, ASDS is deployable from some modified Los Angeles-class SSNs, though the four ex-Trident-class SSBN fleet ballistic missile submarines -- once converted to SSGN cruise missile and special forces carriers -- will be capable of carrying ASDS, as will the Virginia-class attack submarines and the last of the Seawolf-class, USS Jimmy Carter (SSN 23). The ASDS is, says the Navy, a key element in the transformational capabilities of the SSGN.

Several reports, however, indicate that development of the new mini-sub – officially the Advanced SEAL Delivery System (ASDS) – is behind schedule, over budget, and beset with major technical problems.

The Baltimore Sun recently reported that the sub has been tested in the waters off Maryland, with mixed results. The craft – reportedly about the size of a semi truck trailer – has been tested at night, in secrecy, and amid high security. Results of these tests have some critics claiming that the sub’s design has proved faulty, that its costs are out of control, and that it is as much as six years behind in development. In fact, Congress may be ready to scrap the project.

Critics say the craft is too loud for covert operations and that its battery propulsion system does not meet requirements. In 1994, a fleet of six subs was supposed to cost $527 million; one current estimate is now $2.3 billion or more. According to the Sun, Northrop counters that problems have been fixed and that giving the project to a different contractor would simply boost costs in reworking. Northrop has gone as far as warning that the company's Annapolis facility, with 550 employees, might close if the program is lost.

The Advanced SEAL Delivery System first was to have replaced the Mk VIII SEAL delivery vehicle, which is an open craft requiring SEALS to wear SCUBA gear and wetsuits. The ASDS is an enclosed mini-sub, allowing SEALs to operate longer and deeper and to arrive on land in better physical shape. It is to be transportable aboard either a C-5 or C-17 USAF transport aircraft. Westinghouse Oceanic Division (bought by Northrop in 1996 and now the Northrop Grumman Oceanic and Naval Systems Business Unit, based in Annapolis, MD) won the project in 1994 after a three-way bid, with the first vessel to largely use commercial technology and to have been completed in 1997 for $ 131 million. However, mission creep and an unrealistically optimistic development scheme soon caused problems. The sub had to be extended another ten feet and the outer hull had to be redesigned from lighter materials. Its configuration has become ever more grand and complex, until it now resembles a full-function, scaled-down traditional attack submarine. Management was called “inattentive” as costs grew and the schedule continued to slip.

Northrop’s Oceanic and Naval Systems is part of Northrop Grumman Electronic Systems. Naval Sea Systems Command (NAVSEA PMS 395) is running the Navy end of the program. One ASDS exists at this time and its deep water testing was done in 2002 at NS Pearl Harbor, HI. Testing apparently recently moved to Maryland, probably to be closer to Northrop Grumman’s facilities. Boat number one is to be stationed at Pearl, according to Northrop Grumman. This reporter spoke with Deborah McCallum, Manager, Northrop Grumman Media Relations, regarding this program. McCallum indicated that the program is largely on schedule, with three operational trials having been completed in 2002 (Millennium Challenge, Launch and Recovery, and Vehicle Integrated System Test). In May, 2003, a test was completed, during which USS Charlotte conducted an Operational Evaluation (OPEVAL) with the ASDS. During this test, two missions were conducted, with a battery charge between the two. During the test the ASDS’ threshold range, speed, and other capabilities were evaluated. One result of the OPEVAL was the installation of new propeller. Submarines have long been detected and tracked acoustically, with propeller and drive train noise a major component of its “signature.”

McCallum acknowledged two of the program’s critics’ main concerns. “The two primary technical issues [uncovered during testing] were battery reliability and the ASDS acoustic signature.” She indicated, however, that these issues are being addressed. ASDS design requirements dictate “high energy density” (i.e. a lot of power is needed from the battery system). As a result, she told this reporter that technical issues around the use of Silver-Zinc batteries continue to be a problem, such batteries having too short a life cycle. ASDS operations require about 20 full-charge and discharge cycles; current technology yields about four to five cycles. Further, since present recharge time is heavily determined by water temperature and the amount of energy removed, maximum time in hot water and full charge is 5 days – too long (cooler water and less than full recharges can substantially lessen the charge time). So, lithium-ion batteries are now being investigated as an alternative, as they are able to undergo 30 times the number of charge/discharges predicted for Silver-Zinc and can be recharged in 48 hours or less (unfortunately, one severe draw-back with lithium batteries is that they can produce poison gas – about the last thing you’d want aboard a submarine).

Development work continues, and according to McCallum, recently, NAVSEA selected two additional companies (SAFT Battery Corp., Bagnolet, FRANCE, and Yardney Technical Products, Pawcatuck, CT) to compete as an alternative Lithium Ion technology supplier. The anticipated life cycle for the Lithium-Ion battery, according to McCallum, is over 600 full-charge and discharge cycles. The other major design problem -- acoustic quieting – is related to the DOD’s decision to use COTS technology wherever possible, according to McCallum. As a result, ASDS Boat 1 exceeded the noise thresholds. Although during sound trials the propeller was identified as a primary source of noise, the trials also verified previously known internal sources of acoustic noise. The acoustic signature issue associated with the propeller appears to have been mitigated by the design of a new composite propeller by Penn State's Applied Research Lab. Reports suggest that the new propeller substantially reduced radiated noise, though details are classified.

The program is next due for a $24 million payment to begin construction of a second boat, but the Senate Armed Services Committee has threatened withhold payment until questions about the program have been answered to its satisfaction. Amid Congressional concerns and budget realities, the future of a six-boat ADSD fleet remains uncertain.

ASDS-1 rides atop USS Dolphin (AGSS-555) during testing. In June the Navy accepted the first of six planned Advanced Seal Delivery System mini-submarines.