Beneath the Waves

Written by Scott R. Gourley

SOTECH 2009 Volume: 7 Issue: 9 (November/December)

A recent unclassified briefing on U.S. Naval Special Warfare Command maritime priorities acknowledged that command’s responsibilities to USSOCOM for the delivery of special operations forces maritime capabilities.

“In recent years, NSW has significantly grown their maritime mobility capability,” it noted. “From professionalizing the SWCC [Special Warfare Combatant-Craft Crewman] Force as a closed-loop career to maturing surface and subsurface craft as national level assets. Past NSW craft were focused more toward only supporting SEALs, where the focus now is more toward conducting [special operations] with and from platforms. As threats have evolved and as there becomes more responsibility for global presence, NSW’s platforms have evolved from one craft to the next—Seafox to RIB, Mk III to MkV, Mk 8 SDV to Mk 8 Mod 1—to include specifics such as shock mitigation, higher speeds, endurance and survivability.” The briefing went on to acknowledge an expanded range of military operations in a post 9/11 world, with NSW capabilities and materiel working to maintain a balance between capabilities and steadily growing requirements.

The resulting commander’s Maritime Mobility Vision calls for the NSW community to “Field capabilities, including a family of surface and submersible combatant craft, to provide access to and mobility in the maritime domain, for the conduct of Special Operations.” In the “submersible” realm, those expanding capabilities include both manned and unmanned systems.

UNDERWATER SWIMMER PROPULSION/TRANSPORT

Undersea mobility has traditionally presented SOF’s most clandestine capability to deliver tailored forces/payloads, while at the same time presenting unique challenges in extreme/hostile environments. Current SOF undersea manned mobility involves a spectrum of underwater swimmer propulsion and transport devices operating in the range of maritime environments, from brown/green water to the open ocean. Beginning with the diver propulsion device (DPD), the spectrum extends through Mk 8/Mk 8 Mod 1 Combat Submersible Medium, through the Advanced SEAL Delivery System (ASDS) Combat Submersible Heavy, to Submarine Forward Staging Bases, which leverage existing U.S. Navy SSN and SSGN submarine assets through application of SOF assets like dry deck shelters.

The DPD represents a one- or two-man “wet sled” for what NSW characterizes as “very short range” underwater transit applications. Developed by STIDD Systems, the DPD is described as a mission essential surface and underwater mobility platform for combat divers, replacing the traditional mode of physically demanding in-water manual propulsion. In addition to eliminating manual propulsion requirements, DPD allows divers to carry additional gear, reduce infiltration and exfiltration times, cover large distances/areas quickly during reconnaissance/searching tasks, all while conserving both energy and time for other mission requirements.

Along with special operations applications, the DPD will be used by Army engineer dive teams as a means to move personnel and equipment quickly and efficiently while executing port construction, rehabilitation and ship husbandry, and repair.

As a recent industry development, STIDD has introduced the “RNAV” Recon Navigation System, a neutrally buoyant advanced electronic navigation system designed to provide both surface and submerged moving map navigation as well as sonar capabilities to the DPD.

Moving across the manned underwater platform spectrum, swimmer delivery capabilities are expanded through application of the MK 8 series (“Eight Boat”) SEAL Delivery Vehicle (SDV). The NSW inventory of 14 SDVs underwent a service life extension/modernization program in the mid-1990s, resulting in the Mk 8 Mod 1 designation. The Mk 8 Mod 1 SDV is a manned “wet” submersible vehicle used to deliver Navy SEALs and their equipment to mission areas. The crew operates and navigates the submerged SDV while using an underwater breathing apparatus for life support.

The modernization efforts included upgrading approximately 40 percent of the vehicle’s systems mainly covering areas of life support, command and control, navigation and communication. SDV system upgrades included: increased diver air capacity, installation of an onboard Windows-based computer, improved diver communications, addition of satellite communication capability, reduction of GPS signal acquisition time and improved electronics performance and reliability.

However, even with that modernization effort, the Mk 8 Mod 1 SDVs are approaching end of service life (EOSL), beginning in fiscal year 2012, with resulting anticipated increased maintenance requirements and other logistics issues associated with an aging fleet.

One potential solution that emerged involved a replacement effort originally called combatant submersible medium, which would have attributes including: ability to operate in open ocean to 15 feet or less, payload and range improvements over Mk 8 Mod 1, and an open architecture with improved C4I/electronics backbone. Other broad objectives included the ability to operate within constraints of the current dry deck shelter, improved power battery density solutions, and the potential for SSGN vertical launch.

In June 2009, USSOCOM released a request for information “from appropriate companies or parties currently capable of developing and fielding a submarine-launched, free-flooding, shallow water combat submersible (SWCS) vehicle that will provide special operations continued operational capability to conduct SOF shallow water undersea operations similar to those currently performed on the Mk 8 Mod 1 SDV. The SWCS must address a wide range of operational challenges including the growing ability of hostile nations to detect, identify and target SOF conducting undersea tasks. Broad industry participation is desired, but USSOCOM is keenly interested in designs that are currently in production or capable of rapidly entering into production. Delivery date of first production unit is planned in 2015. To complete the study and consider programming initiatives in the FY10 Program Objective Memorandum, USSOCOM requires current industry sources and capabilities information.”

Reflecting on the EOSL complications, the announcement noted, “The Mk 8 Mod 1 SDV is approaching the end of its service life. The system was originally designed around a standard 1553 data bus, making upgrades and replacements no longer cost-effective due to obsolescence. In some cases, increased capability may be available, but the lack of an open architecture prevents cost-effective upgrade of the systems.”

It continued with notional operational scenarios, including, “The new SWCS will perform clandestine transport of SOF personnel and equipment in a wet environment into littoral waters and harbors. The SWCS must address a wide range of operational challenges including the growing ability of hostile nations to detect, identify and target SOF conducting undersea tasks. Thus, the SWCS shall have a modular open architecture design conducive to accommodating upgrades to processors and sensors. Operating in a free-flooding ‘wet’ vehicle, the SWCS passengers and crew transit for extended durations (i.e. up to 12 hours) in a wet, variant temperature environment while breathing from scuba gear. Thus hardware and software selected must feature interfaces that are mission centric to ensure required operator actions are simple and minimized.”

Additional general requirements outlined in the request included: capability for launch and recovery from surface vessels and from submerged host platforms, with the submerged launch and recovery platform being the DDS mounted external to a submarine host platform aft of the sail; loading, manning and maintaining while enclosed in the DDS (total available volume inside the DDS is 8 feet in diameter x 22 feet in length from the bubble window operator station to the apex of the elliptical outer door); crew of two with useable space for additional passengers and cargo maximized for transport of SOF personnel and equipment; primary life support via closed-circuit underwater breathing apparatus for primary life support with an auxiliary opencircuit breathing system capable of sustaining six divers for 1.25 hours at 25 FSW and 8.75 hours at 15 FSW before recharging; minimized acoustic, magnetic, infrared and visual signatures; and maximized cruise speed and transit range via hydrodynamic optimization, motor and propeller selection, and battery design.

Moving further across the underwater manned spectrum, NSW planners categorize an underwater delivery capability characterized under the general heading of Combatant Submersible Heavy (CSH).

The current CSH is the Advanced SEAL Delivery System (ASDS). Measuring 65 feet in length with a beam of 6.75 feet and displacement of 55 tons, the ASDS was designed to provide a high degree of access in threat environments; dry submersible, greater time on station, payload, range than a wet submersible, as well as environmental protection for mission personnel. In terms of operational employment, ASDS can be hosted by the Ohio-class SSGNs, Virginia-class SSNs, LA-class SSNs or launched from/recovered to L-class ship well decks.

Following OSD AT&L [Office of the Under Secretary of Defense for Acquisition, Technology & Logistics] cancellation of additional ASDS procurements on April 6, 2006, NSW planners performed analysis and identified gaps in terms of both capabilities and inventory (one ASDS versus six planned).

Further complicating matters, on November 9, 2008, NSW’s single ASDS (ASDS-1) suffered a major fire while completing a battery charging evolution at SDV Team One compound, in Pearl City, Hawaii, with the fire resulting in what the government described as “significant damage” to the Operator’s Compartment (OC).

With the capability gap clearly identified and the single platform significantly damaged, planners were faced with several options involving repairs and replacements. Just two months after the fire, for example, the government released a request for information (RFI) “to obtain information from industry, including a ROM cost and timeline, to repair and recertify the Advanced SEAL Delivery System (ASDS- 1).”

“The repair strategy being evaluated entails the replacement of all components, including the hull structure, forward of the hatch between the OC and the lock in-lock out chamber,” it stated. “The government has not made a decision to repair ASDS-1 but responses to this RFI would help provide information inherent in that decision.”

The initial visual inspection of the vehicle revealed significant damage to the OC pressure hull structure and to all the systems installed internal and external to this compartment, including but not limited to hydraulics, high pressure air, oxygen, power distribution, external titanium battery bottles, and external fairings and support structure,” it continued. “NAVSEA has determined that one of the viable repair options for the vehicle is the replacement of the entire forward section of the vehicle. The repairs would also include the replacement of all four (4) ASDS hatches. Approach: In order to minimize technical risk and expeditiously return ASDS-1 to operational status, if a contract were awarded, the contractor would be tasked, to the maximum extent possible, to repair the vehicle to the existing configuration. The only exception would be design changes required to address obsolescence issues.”

At about the same time that it was trying to assess the extent of the repair burden, the government also began exploration of a potential replacement approach that would help to close the identified capability gap.

A December 30, 2008, RFI outlined the parallel thread, noting, “A future combat submersible should provide theater SOF commanders the operational capability to conduct insertion and extraction of SOF personnel and/or payloads into and from denied areas from strategic distances. These submersibles would mate to a host submarine using the same interface as that of ASDS-1. The submersibles should be able to conduct clandestine surveillance during extended loiter times at close-in distances. A modular capability and capacity to hold varying payload would enhance its utility for a broad range of missions including intelligence collection, surveillance and reconnaissance in support of SOF objectives. An initial operating capability (IOC) of FY16 is desired for the first of three potential submersible units.”

Throughout 2009, the parallel program matured into an FY10 new program start designated as the Joint Multi-Mission Submersible (JMMS) and described in procurement documentation as “a manned, dry combatant submersible that provides a clandestine mobility platform. It will be capable of operating in a wide range of littoral and threat environments and will be tactically transported by specially modified submarines. The JMMS will provide improved performance over the Advanced SEAL Delivery System and will permit small, highly trained forces to operate in denied areas increasingly controlled by a sophisticated threat. The [FY10] project provides RDT&E funds for analysis and technology development phase efforts.”

According to Lieutenant Nathan Potter, spokesman for U.S. Naval Special Warfare Command, some of the final decisions regarding ASDS repair and/or JMMS replacement strategies are still up in the air as of press time.

“There remains a valid requirement to have ASDS, but due to competing priorities for funds at this time, USSOCOM has not been able to determine the availability of funds to repair it or replace it,” he told SOTECH. “But even though that remains a ‘to be determined’ at this point, there is still a valid requirement to have that capability.”

Finally, although not a transport platform itself, a critical enabling technology for many operations is the DDS. The external shelter is mated to SSN or SSGN submarines for movement of SDV and other payloads. The shelters can be used to launch and recover SDVs or some inflatable combat raiding craft, as well as NSW Mass Swimmer Lock-Out of approximately 20 SOF plus equipment.

With an inventory of six DDS, planners have begun an analysis of requirements for a next generation capability.

UNMANNED UNDERWATER VEHICLES

Although not as advanced as the underwater delivery platforms for swimmers and personnel, the special operations community has also begun fielding its own initial generation of unmanned underwater vehicles (UUV).

Naval Special Warfare Command’s Potter noted that the recent consolidation of the command’s undersea components places NSW UUV responsibilities under Naval Special Warfare Group Three (NSWG-3).

Potter explained that the recent consolidation of SDV teams has resulted in a number of direct benefits for the naval special warfare community, ranging from the establishment of an Underwater Center of Excellence in Hawaii to a “freeing up” of “extra SEALs” through the consolidation process.

Somewhat surprisingly, he observed that UUV applications by the NSW community are somewhat limited, noting, “You might think that they would have a whole arsenal of undersea remotely operated equipment. But they really have just one that they’re willing to talk about, called the SAHRV, or ‘Sheriff’ [semi autonomous hydrographic reconnaissance vehicle].”

Based on the Remote Environmental Monitoring Unit System developed by Woods Hole Oceanographic Institution under Office of Naval Research (ONR) support, the SAHRV was cooperatively developed by the Naval Sea Command and ONR to specifically support Naval Special Warfare missions for USSOCOM. The SAHRV vehicle is an unmanned underwater vehicle that performs reconnaissance (hydrographic and sidescan sonar surveys) in littoral waters, from the seaward edge of the surf zone into waters as deep as 100 meters. Initial sensor packages included a Marine sonics side scan sonar (COTS sonar) and acoustic Doppler/ conductivity Temperature depth/optical backscatter sensor.

The vehicle, which measures 63 inches in length, 7.5 inches in diameter, and weighs 80 pounds, is capable of deployment by two people and can be launched and recovered from a small vessel without a crane or other special handling equipment. SAHRV can operate over 20 hours on battery power before recharging and is capable of speeds over 2.5 meters per second. The primary navigation is by localization relative to long base line transponders. Navigation is additionally supported by an ultra short base line system, Doppler velocity log, and compass. In addition to searching and detecting mine-like objects, system products from reconnaissance missions include water current velocity, seafloor bathymetry, water temperature and salinity, and optical properties of the water.

“SAHRV is one of the first UUVs,” Potter said. “It’s a Naval Special Warfare asset, and it is operational. There are 18 of them total, and they are ‘owned’ by the SDV team. There was formerly an SDV Team Two on the east coast but that is now a Little Creek-based detachment of SDV Team One in Hawaii.

“However, they say that they don’t use SAHRV that frequently,” he added. “Actually the opportunities are few and far between. It does underwater hydrographic reconnaissance so sometimes it ‘paints’ the bottom of the ocean, but they say they really don’t use it that often.”

The SAHRV is characterized as something of a first step in the Navy’s November 2004 “UUV Master Plan,” which notes, “Continued introduction of functional UUVs into the fleet is critical. Fleet sailors have enthusiastically received a variety of small vehicles since the approval of the last Master Plan. Fleet fielded systems such as SAHRV (Navy Special Warfare- NSW) and SCULPIN (EOD) not only provided operational capabilities in contingencies such as Operation Iraqi Freedom, but also provide a critical pool of educated Fleet UUV operators who are a critical link in the evolution of future generations of UUVs. Execution of larger vehicle programs needs to be in accordance with a ‘spiral development’ philosophy. Some capabilities, even if they are interim, need to be provided to the fleet as soon as possible.” The plan emphasized, “A partial technical solution in-use in the Fleet is worth more than perfection in the laboratory.”

But other steps are already under way. Specifically, while Naval Special Warfare representatives limited their comments and observations to the SAHRV platform, other recent briefings have indicated that additional UUV capabilities may be entering the NSW community.

One example of these additional platform capabilities emerged earlier this year during the Association of Unmanned Vehicle Systems International (AUVSI) program reviews, in Washington, D.C. During those briefings, Rear Admiral Mark Kenny, director, Navy Irregular Warfare (IW), identified a number of cooperative initiatives under way in both air and sea unmanned realms.

As a representative IW UUV, Kenny highlighted the Sea Stalker large diameter UUV. With a 38-inch diameter cylindrical configuration, Sea Stalker can be deployed from a variety of naval platforms. The operational design places the main element just underwater with monopole antenna raised above the surface for both command and control and intelligence, surveillance and reconnaissance missions. According to Kenny’s overview, Sea Stalker parameters include a payload suite with “ability to collect on multiple signals of interest” as well as a remote command and control capability.

Shifting to the concept of operations, the overview credited Sea Stalker with contributions toward both counter terrorism and counter narco terrorist operations, through “clandestine transit to/from pre-programmed targeted area of collection” as well as the ability to “rendezvous with naval platforms for recharge/battery change out.” An additional note indicated that the system was “supporting SOCOM, SOUTHCOM and JIATF-SOUTH.”

Another series of autonomous underwater vehicles (AUVs), Hugin and Remus come from Kongsberg and offer a range of capabilities.

Remus 100 is a man portable system cable of being quickly and covertly deployed from small RHIBs. On the opposite end of the product line are the Hugin 4500 and Remus 6000 vehicles that are capable of reaching the deep regions of the world’s oceans with a range of sensors to accomplish diverse mission objectives.

The Kongsberg AUVs are suited for applications ranging from very shallow water mine countermeasures to search and survey applications in the deep ocean. All AUVs can be equipped with a wide selection of sensors—for acoustic and optical imaging, bathymetry, and environmental data collection.

The more advanced sensors are only available on the larger vehicles. Larger vehicles also have longer endurance, superior navigation, and allow simultaneous operation of more sensors. The smaller vehicles are cheaper, easier to transport and deploy. The small and medium sized Remus 100 and 600 carry high frequency side scan sonar (SSS) and bathymetric sensor. The larger Remus 6000 carries SSS and high dynamic range electronic still camera. Hugin 1000 carries multibeam echo sounder (MBE) and very high resolution interferometric synthetic aperture sonar (HISAS), a COTS product from Kongsberg.

The smaller systems can be deployed using standard shipboard handling equipment, whereas the larger systems are deployed with dedicated launch and recovery Systems (LARS). The LARS enables AUVs to be deployed in open water and rough weather conditions, without the need to put a small boat or a diver in the water. The LARS also enables operations on vessels of opportunity.

Kongsberg Maritime recently completed a Hugin 1000 portable AUV system, housed in a 20-foot ISO container for AUV storage, maintenance and LARS, and one 10-foot ISO container housing two AUV operators and the topside vehicle control and PMA system. “This AUV system is unique in the world today, being overnight air-shippable to anywhere in the world, allowing for easy and fast installation on vessels of opportunity with a very small system footprint,” says Einar Gustafson, AUV sales and marketing manager at Kongsberg Maritime’s Subsea Division.

On discussing Kongsberg’s width of AUV offerings, Bjørn Jalving, head of the company’s AUV Department said, “The Hugin 1000 with the HISAS and MBE payloads is today’s most capable and robust AUV system, and is leading the technology development in a highly competitive environment.”

The most recent indications of nearterm UUV program enhancement efforts can be found in a spate of federal/DoD business announcements, such as the October 20 contract award to Woods Hole Oceanographic Institution Grants and Contracts Services to “provide for the development and testing of new sensors for the enhancement of detection from UUVs and to obtain new data analysis capabilities for performance enhancement.”

While current applications may still be somewhat limited, it’s clear that UUVs will play increasingly important roles in special operations applications. ♦

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