Special Forces delivery from Submarines

Since 03-31-04

From NSL UPDATE 01-05-2004

To come unseen: special forces delivery from submarines
Scott R Gourley, Jane's Navy International, 01 Dec 03

The US Navy continues to develop its capability to launch and recover special forces from submarines. Scott R Gourley traces the history and examines the future of this most specialised and covert capability.

Late August 2003 saw the opening of a new chapter in the history of underwater special forces delivery, with a milestone event focused on the deployment of the US Navy's (USN's) first Expeditionary Strike Group (ESG).

Just one year after the ESG concept was originally envisioned, the seven ships of the first ESG left Hawaii on a scheduled eight-month deployment in support of the allied 'war on terror'. Among the platforms and capabilities deployed was the nuclear attack submarine (SSN) USS Greeneville, equipped with the capability to deploy the new Advanced SEAL [Sea, Air, Land] Delivery System (ASDS).

Submarines have long been recognised as an optimum platform for the clandestine deployment of special operations forces (SOF); the history of the Second World War is replete with stories of submarines that quietly surfaced to deliver intelligence agents or raiding teams to combat theatres around the world. This delivery capability was further enhanced with special navy 'frogmen' - swimmers who could exit the craft to conduct reconnaissance and combat missions without requiring the submarine to surface.

The second half of the 20th century saw significant improvement in these capabilities as systems such as the US Mk 6 Swimmer Delivery Vehicle (SDV) - a mini-sub developed around 1964 - began to enter naval inventories. The introduction of SDVs prior to the establishment of SEAL teams probably accounts for their dual identification as 'Swimmer Delivery Vehicles' and 'SEAL Delivery Vehicles'. Further technological and operational improvements led to a series of advances.
Moreover, the late 20th century saw the growing global emphasis on joint service operations translate directly to joint service training for underwater SOF deployment.

As an example, during a 1994 presentation on recent activities of the US Atlantic Fleet, Vice Adm George W Emery (then Commander Submarine Force, US Atlantic Fleet and Commander Submarines, Allied Command Atlantic) emphasised that "1993 was a busy year for the SSNs of the attack submarine force". Noting that 22 of the SSNs had conducted missions involving SOF personnel during 1993, he added: "The stealth of our submarines makes them the perfect platform for the insertion and extraction of special forces, be they air force, marine, SEAL or army, particularly in conjunction with amphibious operations.

We've conducted extensive operations with units from all these services during the last year. For example, in the Atlantic we provided 267 days of submarine services and 34 exercises with 22 different SSNs. Included in that total were 13 exercises and 114 days of Dry Deck Shelter operations, which provide a significantly enhanced special warfare capability."

Dry Deck Shelters

The Dry Deck Shelters (DDS) noted by Vice Adm Emery provide the submarine (host ship) with the ability to participate in special operations involving SDVs, Combat Rubber Raiding Craft (CRRCs - carried deflated, but inflated for surface approach) or mass approach by combat swimmers. Additionally, in the case of SDVs, the DDS allows launch and recovery of the vehicle while the host ship remains submerged.

The DDS consists of three pressure models constructed as one integral unit: a 'hangar' in which SDV, deflated CRRCs or other equipment can be stowed; a 'transfer trunk' to allow passage between DDS and the host ship; and a hyperbaric chamber - the forwardmost compartment - for decompression and recompression treatment of divers. The three modules (constructed from HY-80 steel) are covered with glass-fibre fairings to appear as a single shelter unit measuring 2.74m wide, 2.74m high and 11.6m long, and displacing around 30t. The shelter provides a working environment at 1 atmosphere for the mission team during transit and has structural integrity to the test depth of the host ship.

The original concept for a DDS emerged in the late 1970s with the initial model, DDS-01S ('S' indicates that the door opens to starboard), completed by General Dynamics Corporation's Electric Boat Division in 1982. Between 1987 and 1991, Newport News Shipbuilding manufactured versions DDS-02 to DDS-06, with three of the doors opening to port and two starboard opening doors.

One or two DDS are installed on the host ship immediately prior to the SDV mission, and removed when the latter is completed. Host-ship modifications include a mating hatch retrofit, as well as the addition of electrical penetrations, valves and piping for ventilation; air; and draining water. USN representatives note that the installation of the DDS "does not affect the performance of the host ship appreciably. The few permanent modifications made to the ship do not degrade ship performance after the DDS has been removed". The DDS may be transported to its host boat by barge, trucked over land, or flown via C-5A Galaxy aircraft (each DDS has a specially designed truck for this purpose). Complete on-loading and testing to make the DDS ready for manned operations at sea takes from one to three days.

Submarine to shore

Although capable of considerable operational flexibility, the DDS is most traditionally associated with the Mk 8 SDV, or 'Eight Boat'. The latter is a 'wet' submersible, designed to carry combat swimmers and their cargo in a fully flooded enclosure. Two submerged operators - pilot and navigator - and up to four SEALs with combat equipment are sustained by individually worn underwater breathing apparatus.

A two-man Mk 9 SDV has also reportedly been developed with a combat capability of its own and outfitted with two torpedoes.

The 6.7m-long Mk 8 SDV is propelled by an all-electric propulsion system powered by rechargeable silver-zinc batteries. Buoyancy and pitch attitude are controlled by a ballast and trim system; with control in both horizontal and vertical planes provided through a manual control stick to the rudder, elevator and bow planes. A computerised Doppler navigation sonar displays speed, distance, heading, height above the seabed and other piloting functions. Instruments and other electronics units are housed in watertight canisters.

The system reportedly has a top speed of around 4kt and a maximum range of 36nm, although users note that the 'wet' nature of the craft means that the cold-water exposure can be more limiting than battery power. The early 1990s saw the development of an updated version of the SDV, introducing significantly increased range, speed and maintainability over previous SDV models. Subsequently designated as Mk 8 Mod 1, the service-life extension package was developed by Naval Sea Systems Command's (NAVSEA's) Coastal Systems Station (Panama City, Florida). The updated SDV was reintroduced into Naval Special Warfare Command (NAVSPECWARCOM) inventories in 1996.

A further three Mk 8 Mod 1 SDVs were delivered to the UK in 1999 (the UK previously operated the ageing Mk 8 Mod 0 SDV), for use by the Special Boat Service. Under a separate activity known as Project Alamanda, the UK Royal Navy's Swiftsure-class SSN, HMS Spartan, has received modifications to allow it to receive a UK-designed dry-deck hangar facility.

ASDS arrives

While the scientists, engineers, technicians and logisticians at the Coastal Systems Station were developing the Mod 1 upgrade, special operations planners were looking towards developing the ASDS to meet requirements for a revolutionary improvement in underwater insertion capabilities for the 21st century.

The major improvement of the ASDS concept over the legacy SDVs was that it called for a 'dry' boat, capable of delivering a fully equipped SEAL squad into hostile environments without exposing it to the sea. The new system would offer enhanced range, endurance, payload and habitability over previous SDVs. The improvements are so significant that NAVSPECWARCOM representatives characterise the programme in terms of "new capabilities rather than just a new system".

Three preliminary design contracts were awarded in November 1992, with eventual programme downselect and award to Northrop Grumman Corporation's Oceanic & Naval Systems business unit. Company releases highlight the system as "a mini-submarine intended to clandestinely carry navy SEAL teams and their combat gear to and from hostile shores. This first-of-its-kind system is transported to a mission area atop an attack-class nuclear submarine, or it can be airlifted with its land transport vehicle by C-5 or C-17 aircraft for insertion and deployment to littoral theatres worldwide".

On a parallel track with development of ASDS Boat 1, USS Greeneville began conducting shakedown operations in the western Atlantic from February to July 1996. A post-shakedown availability was conducted at Newport News Shipbuilding and Drydock Company from August 1996 to February 1997, to perform various alterations to improve noise quieting and equipment reliability, and to install support systems for the Deep Submergence Rescue Vehicle as well as for the ASDS.

Powering the challenges

Providing the ASDS with optimised speed and range capabilities shifted the technology spotlight onto the batteries powering the electric motors. March 2000 saw NAVSEA representatives announce the command's intent to procure ASDS batteries from BST Systems Inc. The announcement identified the company as "the designer, developer and sole manufacturer and the only firm possessing the required knowledge, data, equipment and facilities necessary to perform the effort in the required time frame". Late October that year saw a follow-on announcement describing the battery procurement as "1,288 Advanced SEAL Delivery Systems battery cells, 56 sample cells and 112 spare cells".

However, in August 2001 Northrop Grumman Corporation was awarded a US$4 million contract by NAVSEA for the development and integration of lithium-ion battery technology. Noting that the new battery system was being developed in conjunction with Alliant Techsystems, the Northrop Grumman announcement quoted Bruce Ballantyne, director of Special Defense and Submersible Programs: "The emerging lithium-ion battery technology promises a 20- to 40-times improvement in life cycle and reduced operational cost when compared with traditional battery technologies. This technology enables the navy to expand the types of missions the ASDS can perform."

In September 2003 a third company, Saft America was awarded a contract to design, build and deliver a lithium-ion battery for ASDS. Obtaining a battery so far has proven a real sticking point for the programme so far, but Northrop Grumman assured JNI that the problems have since been solved and the programme is well on track. As this new battery technology was being developed and refined, the ASDS was participating in fleet exercises. In late August 2002 Northrop Grumman announced the completion of the first ASDS operational mission under the umbrella of Joint Forces Command's Congressionally mandated Exercise 'Millennium Challenge 2002'.

On 1 and 2 August 2002 ASDS Boat 1 successfully delivered SEALs and their equipment to a precise drop-off point off the coast of Hawaii during night-time exercises. Additionally, lock-out operations were completed, enabling the submerged departure of SEALs and their equipment. The last step was the submerged recovery of SEALs at mission completion.

According to Fran Holian, vice president of Northrop Grumman Oceanic and Naval Systems, the ASDS "provides a new level of operational capability to our SEAL forces in high-threat areas". He added that "these key milestones help ensure our naval forces continue to have the most technologically advanced equipment for today's critical missions".

ASDS Boat 1 has been undergoing an aggressive schedule of testing since December 2001, preparing it for an operational evaluation in mid-2003. This included the trialling of docking and launching manoeuvres from a 'stationary primary host simulator' that replicates the mating structures on a host submarine. Boat 1 also demonstrated a submerged anchoring capability, and conducted diver lock-in/lock-out operations. These tests were designed to prepare the boat for dynamic launch-and-recovery operations from USS Greeneville in mid-2002.

Accordingly, in mid-September 2002 Northrop Grumman announced that Boat 1 had successfully completed multiple launch-and-recovery docking scenarios with the USS Greeneville. The successive dockings over a period of several days further validate the ability of the system to operate in the undersea environment. "This was the last major hurdle for this unique warfighting system," said Capt Joe Fallone, programme manager (PMS395), Deep Submerge Program, and the NAVSEA ASDS programme manager. "A lot of hard work went into making this trial a success. We are now one step closer to giving the special operations warfighter a remarkable capability."

In addition to the USS Greeneville, the USS Charlotte (SSN 766) is currently configured and certified to host the ASDS, and returned from its final sea trials with the system in May 2003. The USN's fleet of Virginia-class SSNs will be capable of mounting the ASDS, and the navy also plans to modify the four Ohio-class nuclear-powered ballistic missile submarines, scheduled for conversion to nuclear-powered cruise missile submarines (SSGNs), to carry up to two ASDS vehicles each, all of which should be in service by the end of the decade.

On 26 June 2003 NAVSEA representatives signed the US Department of Defense form DD250 to signify the official delivery of ASDS Boat 1 into navy hands; and the departure of the fully compatible Greeneville on exercise marked a new beginning for USN special forces delivery. Assuming that the ASDS is not required overseas for combat deployment, a look at the US Special Operations Command's (USSOCOM's) Fiscal Year 2004 (FY04)/FY05 biennial budget estimates provides a glimpse of where the ASDS programme might be headed in the next few years.

For example, one FY04 line item addresses Boat 1 alterations, to include the installation of the new lithium-ion batteries noted earlier. In addition, further funding has been requested in FY04 and FY05 to procure long-lead materials in support of a projected FY06 production contract award for ASDS Boat 2. Delivery of the second boat would take place in FY09.

Beyond ASDS

But the story does not end with the ASDS. Planners are already looking to the development of new technologies and capabilities for the underwater delivery of SOF personnel. One example of these new capabilities can be found in USSOCOM's Swimmer Transport Device (STD) programme.
In March 1997 USSOCOM acquisition representatives conducted an open market survey for the STD. This set out a range of characteristics and minimum specifications for the system.

Foremost among these was that the STD must be a 'non-developmental item', which would speed the system into service, produce lower costs and circumvent the complicated and often expensive development schedule that comes with developing equipment. Despite this, USSOCOM set out that the STD must be deployable to all mission areas and survive all weather conditions as specified in the standard Naval Special Warfare environmental parameters.
To ensure that the STD is compatible with the ASDS and the larger SSN and SSGN host submarines, the criteria dictated that the dimensions must be such that the STD will pass through an 11.8cm-diameter access hatch and its length shall not exceed 31.5cm. In addition, an equipment compartment was deemed desirable but not essential.

The rest of the requirements related to the STD's ability to reach the target, stating that it must operate on self-contained power, and that a navigation system that provides - at a minimum - speed, distance and course data for a dead-reckoning solution is highly desirable. On top of this, a battery-voltage discharge indicator is required to keep the operator apprised of range and endurance remaining, with "a diagnostic test kit for monitoring and testing systems to ensure normal operations".

Based on the results of the survey, the command issued an announcement in April 1999 of their intent to acquire an STD that will provide an intermediate transport capability to augment the ASDS submerged-insertion requirements. STDs will enable the ASDS to loiter in deeper water away from the direct insertion zone, and will transport SOF combat swimmers (wearing underwater breathing apparatus) and their mission-essential equipment out to shallow-gradient target areas and, post-mission, return them to the ASDS. USSOCOM states that "the STD will assist SOF combat swimmers to transit longer distances, while delivering increased payload, in more adverse conditions".

The announcement included an expanded range of specifications in terms of Key Performance Parameters (KPPs), which were further broken into 'threshold' and 'objective' levels. While not being prescriptive about the appearance of the STD, these KPPs set out that the system should be able to meet a threshold capability of towing one combat swimmer and 80 lb of neutral-load equipment out to a target 5nm away, and then returning, with an objective range of 7nm.

The notice also set out that the STD must be able to tow the swimmer and their equipment at a threshold speed of not less than 2kt with no current, but objectively at 3kt with no current.
Moreover, the specifications were now refined to address more specific characteristics. As an example, the original requirement to "pass through an access hatch 30in [11.8cm] in diameter" was now replaced with the requirement that: "In its entirety, or in modules, the STD must be carried [within] an ASDS, and be able to pass through a 25in [9.8cm]-diameter hatch."

STIDD Systems Inc. received the initial STD contract in late September 2000. The company describes the programme as "[offering] divers a fast, rugged and reliable means of underwater mobility, travelling farther and faster with more equipment than possible with any previous diver-propulsion unit". The STD takes the shape of a relatively small submersible body, with a battery-powered single screw pushing the craft through the water.

Another recent example of USSOCOM's investigation of new and supporting technologies can be found in the Surface Planing Wet Submersible (SPWS). STIDD Systems also won the contract for this system - worth US$21.3 million - from USSOCOM in early September 2001 - an award that is often forgotten because of the chaos of the terrorist attacks on 11 September that year.

When contacted, the company declined to talk about the programme, referring all enquiries back to NAVSPECWARCOM - which was equally reticent. However, STIDD notes that the "SPWS carries divers and their equipment over long distances on the surface at high speeds... then transitions quickly and proceeds submerged to the objective. The SPWS is currently manufactured by STIDD Systems under contract to the US Special Operations Command".

Although exact details are classified, JNI believes that the SPWS is capable of carrying a six-man SEAL team up to 165nm at a cruising speed of 30kt while on the surface, and for 18nm at 6kt while submerged. Unlike the ASDS, the SPWS is a 'wet' submersible - as the name suggests - exposing the occupants to the water as in the USN's existing SDVs. The depth to which the vessel can submerge, how it is powered while submerged and whether it can snorkel to recharge are all classified.

In 2002 USSOCOM stated that it has no definite 'requirement' for the craft and is only using the prototype as a 'technical demonstrator'; however, the command continues to fund the SPWS' development. (North Korea reportedly has a number of similar vessels for high-speed agent insertion, travelling at high speed on the surface - possibly up to 35kt - and then submerging to a depth of 3m, powered through a snorkel at 4kt, to deliver SOF personnel and intelligence agents close in shore.)

Nevertheless, further details are not forthcoming, and both NAVSPECWARCOM and USSOCOM declined to comment specifically on the SPWS programme. However, an USSOCOM  representative offered the following generic admission about the contract award: "one of our key functions here [at USSOCOM] is to equip America's elite special operations forces with any kind of advanced specialised vehicle or equipment that they need. So this is something that would definitely fit under our purview. And when we, here at the headquarters, look to the future of special operations we have four essential characteristics that we're looking at. And something like this vessel here would probably hit all four of our key essential characteristics that we need. And those four are: greater strategic agility; global access; ubiquitous presence; and information dominance. Now whether or not it can do all those things, I can't tell you...".

As with modern SOF personnel worldwide, the subordinate components of USSOCOM have long prided themselves as being 'the quiet professionals'. USSOCOM's recent change in commanders has resulted in a new emphasis on the adjective 'quiet'. The shutters are coming back down and recent service responses seem to indicate that specific emphasis has been directed towards the ASDS and related underwater delivery programmes.

Nevertheless, although some of the available information on ASDS and other programmes within the naval special operations arena has begun to slip back beneath the waves, several aspects of the activities and capabilities surfaced long enough to provide a representative glimpse of what is to come.

C.J. Ihrig

President, Capitol Chapter