New Rescue System Replaces Submersibles



The Navy has officially placed in service a new submarine rescue capability, replacing its long-serving and highly versatile rescue submersibles. The Submarine Rescue Diving and Recompression System (SRDRS)replaces the submersible Mystic, the Navy's last Deep Submergence Rescue Vehicle (DSRV).

The SRDRS, according to Navy statements, "is a rapidly deployable rescue asset that can be delivered by air or ground, installed on pre-screened military or commercial vessels of opportunity. . . and mated to a distressed submarine within a 72-hour time to first rescue period."

Unfortunately, only two of the three major components of the SRDRS are now available, and the system in some ways lacks the flexibility of the now-discarded DSRVs. The SRDRS is a three-phased acquisition program:

The first phase was the Atmospheric Dive System 2000 (ADS2000), which was delivered to the Navy in 2006. This is a manned, one-atmosphere dive suit that enables a diver to inspect a disabled submarine on the ocean floor to a depth of 2,000 feet, i.e., approximately the "crush depth" of the U.S. Navy's deepest-diving submarines. The diver would also have a limited ability to clear debris from escape hatches.

The second phase is the Rescue Capable System (RCS), delivered to the Navy in October 2008. This system is based on the "Falcon," a tethered, remotely-operated, pressurized rescue module that is lowered from the surface ship to "mate" with the escape hatches on a disabled submarine. The survivors climb into the module, which is then brought back up to the surface ship. The RCS also includes the ship-based launch and recovery system, and controls. The Falcon can conduct rescue operations to a depth of 2,000 feet, can mate to a disabled submarine at a list and trim of up to 45 degrees, and can transfer up to 16 personnel at a time.

But the third phase of the SRDRS -- that will not be delivered until late 2012 -- is the submarine decompression system. This will enable rescued submariners to remain under pressure during the transfer from the rescue module to hyperbaric treatment chambers aboard the surface ship to prevent their being affect by the "bends" as they reach surface pressure after being in a disable submarine that might have increased internal pressure.

The Navy touts the SRDRS as being air transportable and then able to be taken to sea in a variety of pre-designated U.S. and foreign naval and merchant ships.  However, being a surface-based system, the SRDRS is vulnerable to bad weather and rough seas and, of course, could not affect a rescue under Arctic ice.

The SRDRS underwent a test and operational evaluation during the international submarine rescue exercise Bold Monarch in May-June 2008. The rescue module transferred personnel from three participating submarines -- from Norway, the Netherlands, and Poland. More recently, the SRDRS conducted an exercise with the Chilean submarine Simpson on 17-18 September 2008.

The SRDRS replaces the rescue submersibles Avalon (DSRV 2), which was deactivated on 1 September 2000, and the Mystic (DSRV 1), deactivated on 1 October 2008. Both DSRVs became fully operational in late 1977, although they were completed several years earlier. The DSRVs, also air-transportable, could be carried and supported by specially designed surface ships -- that have since been discarded -- and submarines (SSN and SSBN) that have special fittings provided. Several U.S. and foreign submarines were modified to carry a DSRV. The rescue submersible could then be carried to sea and both launched and recovered from the submerged "mother" submarine.

The DSRV could mate with all U.S. submarines except for the new discarded NR-1 and Dolphin (AGSS 555) as well as most foreign submarines. A DSRV could carry 24 survivors (plus 3 or 4 crewmen), and could transport them under pressure to the mother submarine, which could also have a pressurized compartment to receive the survivors. And, with the DSRV there was no need to place a diver on the disabled submarine, in part because the DSRV had a capability of both examining the submarine and clearing debris from a hatch. However, while the DSRVs had a capacity of 24 crewmen compared to 16 for the Falcon rescue chamber, the latter received power through its tether while the DSRVs required a two-hour battery charge between rescue cycles.

The two DSRVs were built as part of the comprehensive Deep Submergence Systems Project (DSSP), established following the loss of the nuclear-propelled submarine Thresher (SSN 593) in 1963. Two DSRVs were built, each weighing 37 tons and just under 50 feet in length. They had an operating depth of 5,000 feet -- far beyond the collapse depth of U.S. submarines -- and, because they could be clandestinely employed from submarines, they provided a very use capability for special missions.

The DSSP also sponsored the development of advanced emergency submarine location devices, submarine escape gear, the ability to locate and recover small objects on the ocean floor, and a large object salvage capability. It was also responsible for developing systems for the nuclear-propelled research/recovery submersible NR-1.

-- Norman Polmar

Show Full Article

Related Topics