Under the Surface - SDVs

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Under the Surface

The key issue for future swimmer delivery vehicles is the degree to which it is technologically possible to deliver combat swimmers close to their objective in a dry—and warm—environment


By Adam Baddeley

The key issue for future swimmer delivery vehicles (SDV), which provide the clandestine capability to launch and recover special forces from submarines and other platforms, is the degree to which it is technologically possible to deliver combat swimmers close to their objective in a dry—and warm—environment, boosting mission endurance and effectiveness. For the U.S., how this will be decided will depend on the outcome of a review of the troubled Advanced SEAL Delivery System (ASDS) program. The core concept of the Navy’s 65-foot long, 8-foot diameter ASDS is ensuring that its occupants remain dry while deploying relatively close to their objective, speeding there at a reported rate of eight knots at depths of beyond 150 feet. Its size is atypical, with a crew of two and a team of eight combat swimmers, with its own on-board decompression chamber. The ASDS is to be launched from either a dry deck shelter on an SSN or alternatively a surface vessel with a dock.
The ASDS program began in earnest in 1994 with an award to the then Westinghouse Electric Corporation’s Oceanic Division, now part of Northrop Grumman. The original program was to have delivered the first of six boats by 1997, but the only boat delivered took 10 years. ASDS-1 is today cleared only for limited operational service
Although not meeting all requirements, ASDS-1 was accepted by the Navy in June 2003. Despite significant investment and delay, only one out of the planned fleet of six have been delivered, with further deliveries halted in April 2006 by the DoD, while the entire program, and all of its options, was reviewed. The options now being considered are whether to invest further funds in ASDS or whether alternatives should be pursued to deliver the operational requirement through a new competition. A decision on how to proceed is scheduled for mid-2008
Thus far the costs of ASDS have been high, a May Government Accountability Office (GAO) report found total program costs had reached $885 million, making it one of USSOCOM’s largest investments. Since its “as is” acceptance by the Navy, $84 million has been spent in additional design, integration and reliability improvement work to rectify deficiencies. The same report strongly criticized the Navy for failing to control contractor costs, schedule and performance criteria and outlined criteria under which the current ASDS should be cancelled.
In a statement Northrop Grumman said, “On the whole, the GAO report correctly presented the facts on the ASDS program, however, Northrop Grumman Corporation [NGC] does not fully agree with all of the conclusions that were made. The ASDS program has been a very complex and difficult program from the beginning. As a combat submersible, it must balance elements of both submarines and manned submersibles to create a vehicle that is robust and combat capable. That combination gives rise to a very unique and difficult engineering program.
“Northrop Grumman Corporation has been unwavering in its support and commitment to delivering the ASDS, despite the many challenges. NGC has taken an overall corporate approach to the ASDS program management. Northrop Grumman Newport News has been brought in to provide the submarine expertise and rigor as well as provide program management oversight. As a result, the ASDS has demonstrated significant improvements in operational readiness and reliability.”
ASDS was decertified for operational test readiness in October 2005 because of recurring performance and reliability issues, the final catalyst being a propulsion-related failure linked to its tail assembly design. In September 2005 the Navy and USSOCOM had already formed the ASDS Reliability Action Panel to independently assess the ASDS’ reliability. In response to the resulting report, USSOCOM adjusted the program to focus on rectifying reliability issues on the existing vessel. The DoD stepped in, in April 2006, and cancelled further ASDS boat acquisition and established a parallel ASDS improvement program, with the ASDS-1 being maintained in-service with an improvement program running through FY08, while assessing alternative materiel solutions to deliver an ASDS capability.
As part of that review process, the ASDS Phase 1 critical design review reported in June this year, looking at how corrective actions would be prioritized and how more granularity could be added to cost and schedule estimates. NGC commented, “As reported in a May 23, 2007 letter report to Congress by Under Secretary of Defense [Acquisition, Technology, and Logistics] Kenneth Krieg, on the ASDS program...the reliability improvements suggested from the [Critical Systems Review] phase one review that have been installed on ASDS-1 have produced an increase in system reliability in both at-sea ASDS-1 operations and through modeling and simulation. The specific priority for improvements to ASDS-1 will be determined by USSOCOM and NAVSPECWARCOM.” [Krieg resigned from this position in late July 2007.]
A joint Navy-USSOCOM report looking at gaps in SOF clandestine maritime mobility gaps should be competed by February 2008. This following an earlier submission by USSOCOM alone, on the same subject to the Joint Requirement Oversight Council in 2007.
ASDS improvements thus far are, however, paying dividends. In testing from February to March this year ASDS-1 operated for 113 hours undertaking nine underway with no failures. In a statement NGC said, “Over the past 18 months, at USSOCOM’s request, NGC has planned and executed a number of maintenance availabilities for ASDS, during which several system improvements have been incorporated into the vehicle. During that same period, ASDS has operated nearly failure-free during numerous at-sea periods. The specific capabilities of ASDS are not available for public dissemination.”
By mid-2008 the information will be in place to make a decision on how to progress.
Industry believe that if ASDS or ASDS capabilities are re-bid, large primes like Northrop Grumman, with maritime platform and systems experience are likely to bid. It is still considered an open question on whether the DoD will sanction an ASDS Mk 2 due to recurring concerns over whether technology is sufficiently mature to field a dry submersible at this time and whether a more hybrid capability will be adopted, opening the field to smaller, specialized contractors.

Other Programs


In parallel to ASDS conundrums, new and existing SDV capabilities are being acquired and sustained within the DoD inventory.
The Mk 8 Mod 1 SDV is the current U.S. Navy in-service solution and will remain in service until 2012. Developed as a service-life extension package by Naval Sea Systems Command’s Coastal Systems Station, it was introduced in 1996. The Mk 8 Mod 1 improvements comprise an improved aluminum frame, better electronics, navigation and sensor systems as well as a quieter all-electric propulsion system.
The Columbia Group Marine Engineering Division is the U.S. Navy’s support contractor for SDVs. Ross Lindman, vice president of the division said, “We provide engineering and fabrication support for upgrade support of U.S. Navy SDVs including the Mk 8 Mod 1, under a long-term contract with the Navy. We overhaul, refurbish and upgrade those boats every year. We also do similar things for a number of other customers.
In doing that, we both build and design our own Dolphin Class SDVs in service with friendly foreign countries and maintain and upgrade what is owned by the U.S. Navy.”
One of the principle differences between the Mk 8 Mod 1 and the Dolphin, the company’s main export SDV, is largely one of size influenced by a slightly different mission, explained Lindman. “In the case of the Mk 8 Mod 1 the U.S. Navy has constraints on size because that vehicle has to fit into the U.S. Navy’s dry deck shelter, whereas other customers deliver their SDVs from surface craft or in other ways that don’t have those size and volume constraints.” The Columbia Group is currently in negotiation with two countries for the Dolphin.
The Dolphin is an eight-man SDV, which uses a high-torque, brushless low rev direct current motor to ensure low noise and can reach speeds of above 9 knots and has a cruising range of over 70 nautical miles. The company also produces the Piranha designed to carry two crew 60 nautical miles at a cruising speed of 5 knots.
Lindman explained that the company is now looking at SDV technology issues for a program that the U.S. Navy has called SDV Next. This will be the next generation swimmer delivery vehicle, which will follow the Mk 8 Mod. 1 The Navy is currently engaged in developing the requirements for that particular craft and consequently it may be different from the Mk 8, due to different missions and support requirement and may be an entirely different boat than the existing Mk 8 Mod1.
Discussing the company’s technology priorities, Lindman said, “We are focused on extending the range of SDVs. Because it is a wet submersible, you can always make the machine go further than the man’s endurance in the water. The limit is always the diver. The only way to extend the range is to go faster. So we are looking at technologies in the propulsion system that can have the SDV travel faster with a faster average speed so they can cover more ground during the time the man can be in the water.”
The Columbia Group is also looking at advanced navigation systems and situational awareness tools to help the SDV crew know what threats there are in the area to avoid them. “One only has to look around the world today to see the emphasis on harbor security has led to more swimmer defense systems being deployed. Looking at it from the dark side, we want to answer the question of how do you get around those.”
STIDD Systems Inc. is currently supporting the U.S. and allied SOF community with two programs in the SDV domain. Over 200 of STIDD’s diver delivery systems are currently in DoD service as the Swimmer Transport Device for USSOCOM and the Diver Prolusion Device (DPD), used by the Marine Corps and Army Special Forces. Aside from a few unique USSOCOM features, the systems are essentially the same. Another approximately 100 units are now with SOF partners in Europe, Asia and other locations.
“The DPD enables combat swimmers to move men and equipment over long distances while on the surface, or while submerged, minimizing fatigue and increasing time available on the objective. The DPD has evolved into a proven, reliable insertion platform for combat swimmers. When operators realize there is a credible COTS mechanical means of propulsion available, it’s a real breakthrough moment; they don’t have to deal with 10,000 meter open water swimming anymore,” said STIDD’s David Wilberding.
One of the real attributes of the DPD, according to Wilberding, is its massive-unit small-cell lithium energy system, or MUSCLES battery. “MUSCLES provides unprecedented performance with over 2.5 hours of operation at speeds over 3 knots with up to 10 nautical miles range with an extended range option. This latter option consists of two batteries coupled together which effectively doubles the DPD’s range,” explained Wilberding.
Now in full rate production, the DPD will be further enhanced by two new optional upgrades available in late 2007; an underwater electronic navigation system called RNAV and an acoustic locator capability.
“RNAV is based on a platform of COTS marine electronics, coupled to a proprietary GPS antenna with articulating locking mast, hard-mounted to the DPD, that is deployed and stowed by the diver while underway, enabling the attainment of positive GPS lock while running submerged,” Wilberding said. STIDD placed all of this functionality in proprietary pressure containers, enhanced with a backlit color screen and a user-friendly through-the-screen gloved hand push button interface, enhancing accurate underwater navigation, mission planning and situational awareness.
Wilberding added that the introduction of acoustic locator capability “will allow a group of DPDs to drive in formation while submerged, or find each other at night in limited visibility. The addition of RNAV and acoustic locator capability to the DPD will improve safety and reduce the command and control challenges of having multiple DPDs in the water simultaneously, making the DPD an even more capable, user-friendly and cost-effective diver delivery vehicle.”
STIDD is also in full-rate production of the 32.5-foot multi role combatant craft (MRCC) that operates on the surface, semi-submerged, and fully submerged. The MRCC is another STIDD COTS platform, but further details of its specifications and design will be featured in a subsequent article.



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