Should a submarine get into difficulty, the NATO Submarine Rescue System (NSRS) is ready around the clock for deployment to provide assistance. Here we look in detail at the history, capabilities and future of NSRS.
The RN has not lost a submarine in an accident at sea since HMS Affray sank near Alderney in 1951. As an inherently dangerous business, the safety record of modern RN and NATO submarines is exceptionally good, although there have been several close calls including some not in the public domain. Despite the high standards of maintenance and operation, the risk of a submarine becoming trapped on the seabed remains a possibility. A credible rescue capability is therefore an important backup for any submarine force and a statement that the navy cares about the welfare and safety of those serving.
It is theoretically possible for personnel to evacuate directly from a bottomed submarine and ascend from the escape tower to the surface using escape suits. The RN trains its submariners in Submarine Escape, Rescue, Abandonment and Survival (SMERAS) techniques. However, this is fraught with risk and is a last resort option that is only viable at relatively shallow depths. Rescue by another submersible is a far safer means of escape where possible.
The NSRS can perform rescues down to depths of 610 meters, essentially covering the continental shelf but it should be remembered that about 90% of the ocean is more than 1,000 meters deep. Should an incident cause an uncontrolled descent in the open ocean, the boat would exceed crush depth, implode and be far beyond rescue. However, attack submarines at least, tend to spend a disproportionate amount of their time in shallower waters, either operating off coasts or in transit to their bases. NSRS is primarily intended to cover Northern European waters but overlaps with rescue systems provided by other navies worldwide.
Fortunately, NSRS has yet to be called upon for a live DISSUB (Distressed Submarine) event by any nation. There is a common bond among submariners that may transcend international tensions and submarine rescue is often a collaborative endeavor, most recently demonstrated by the effort to locate the lost Argentine boat ARA San Juan in 2017 and Indonesian boat KRI Nanggala in 2021.
In August 2001 the LR5 was flown to Norway and was prepared to dive on the Russian Oscar-class SSGN RFS Kursk that had suffered a catastrophic torpedo explosion and had sunk in the Barents Sea. Russian delays in accepting foreign assistance prevented LR5 from being deployed, although subsequent investigation suggests the survivors of the initial explosions only lived for a few hours afterwards.
In 2005 the Scorpio intervention ROV was employed to save the lives of 7 Russian submariners. The Priz-class submersible AS-28 became entangled in nets while working on acoustic arrays off the coast of Kamchatka in 2005. Hard to believe in today’s context, but subsequently, Vladimir Putin personally awarded medals to 5 of the British personnel involved at a ceremony hosted in 10 Downing Street.
Roger Champan was an ex-RN submariner who narrowly escaped death when working in a commercial submersible on trans-Atlantic phone cables in 1973. The Pisces III became trapped on the bottom and was finally rescued when ROVs attached cables to lift the boat from the seabed. As a result of this experience, Chapman founded Rumic Ltd and designed the LR5 manned rescue submersible which provided submarine rescue services to the RN from 1983. In 2004 Rolls Royce was appointed prime contractor in partnership with Rumic to develop a new NATO rescue system and in 2008 the SRV1 entered service, replacing the LR5.
James Fisher Defence (JFD) acquired Rumic and in 2015 was awarded the Second NSRS In-Service Support contract which was extended in 2020 to run until next year. A competition for the third In-Service Support Contract is underway, due to commence in January 2023 and run for 5 years with the option to extend a further 4 years out to 2032. JFD is an example of British export success, they also provide their specialist submarine rescue expertise to the navies of India, South Korea, Singapore and Australia.
NSRS is an international collaboration comprising three participant nations, France, Norway and the UK, sharing the costs between them. In the event of a DISSUB incident other NATO and possibly non-NATO nations could request assistance and financial compensation would be resolved afterward. NSRS runs on a government-owned, contractor-operated equipment model with JFD as the prime contractor responsible for managing the supply chain, maintenance of the system and mobilisation when called upon. It is up to the MoD to arrange air transport provided either by the RAF or commercial charter. They are also tasked with locating and securing appropriate Vessels of Opportunity (VOOs) to transport the rescue system to the site of the DISSUB. The rescue would be managed by JFD, including bridge operations, launch/recovery, and piloting of the SRV while the participant nations provide the military leadership, medics and Transfer Under Pressure System (TUPS) operators.
JFD’s naval architects hold a register of potential VOOs or motherships thought to number around 2,000 that are capable of hosting the rescue or intervention systems. These include large diving support ships, cable ships and other offshore supply vessels which have sufficient deck space, capacity for the rescue team and survivors as well having adequate speed and the ability to operate in high sea states
The Intervention System
The NSRS team at Faslane is on standby 24/7 and on receipt of a SUBSUNK notification would respond roughly as follows. The first major component of the NSRS in the Intervention system, designed to provide the initial response, with the primary task of localising the DISSUB, making contact with those on board and delivering emergency supplies. Held at 6 hours notice to move, the intervention system is packed onto 4 lorries at Faslane for transport to Prestwick or another airport, loaded onto aircraft and flown to the nearest airfield to a suitable VOO. This system is transported from the airport and loaded onto the ship which then sails for the approximate location of the DISSUB. The target time for the intervention system to make contact with the DISSUB is within 56 hours. Depending on the circumstances, actually locating the submarine in trouble may be the hardest part of the rescue operation, a process that will be started well before the intervention system is on scene.
The IROV is deployed from the VOO to pinpoint the position of the submarine, survey the site, drop transponders, inspect the rescue escape hatch and remove any debris that could obstruct escape. The IROV can also deliver Emergency Life Support Stores (ELSS) pods which may contain medical kit, food/water, oxygen candles or CO2 scrubbers. The hatch is opened by the submariners below and the ELSS is dropped into the escape tower in a process known as ‘pod posting’. The main hatch is then shut and the ELSS can be recovered by the submariners opening the hatch at the bottom.
The Rescue System
The second major component of the NSRS is the larger and more complex Rescue System which requires 18 lorries to transport its elements. It follows on behind the Intervention System, with a target time of 72 hours to begin rescue work. In an incredible logistic feat, the system is also moved by road and air and onto a VOO. The work to install the equipment onto the ship is demanding, requiring the 100-tonne Portable Launch and Recovery System (PLARS) to be assembled and welded or bolted to the decks. The SRV, together with the large TUPS which includes two decompression chambers and many other items must be embarked and set to work in a very short timeframe. A team of more than 70 people are expected to complete the equipping of the ship within around 18 hours after the last component arrives on site.
When the precise location of the DISSUB is known and the rescue system has arrived on site, the SRV is deployed and dives to the submarine. The pilots must precisely manoeuvre the SRV to align the dry-mating skirt over the escape hatch. As the DISSUB is unlikely to be lying exactly flat on the seabed, the system is designed to allow the SRV to mate with a boat lying up to 60º from the horizontal.
Once in place, pumping water out of the skirt creates sufficient pressure differential to lock the SRV to the DISSUB. The hatches can then be safely opened allowing the first batch of submariners to climb up into the rescue chamber of the SRV. As a damaged submarine may have suffered progressive flooding, the internal air pressure may have been considerably raised beyond normal atmospheric level. The rescue chamber air pressure is therefore raised to match that of the submarine and is sealed off from the forward command module where the two pilots control the SRV.
The SRV then ascends to the surface, is lifted on board the VOO, slides back on a rail system and its rear hatch makes an air-tight connection to the TUPS. This maintains the air pressure and the submariners can then exit into the decompression chambers where the pressure is slowly reduced over a number of hours to avoid the effects of the bends (Decompression sickness).
The only way to meet the targets for such a rapid response is through constant practice. Either once or twice a year the intervention and rescue systems go to sea. NSRS participates in exercise Dynamic Monarch, a multi-national NATO DISSUB rehearsal conducted every 3 years. The system is also deployed at sea to one of the three participant nations every year.
Individual elements of the system are also exercised independently. Pilots train on the SRV at the Underwater Centre in Fort William, PLARS assembly is practiced ashore on a plinth, and TUPS operators and medics train at Faslane. Around 15 JFD staff carry out routine maintenance at Faslane, supported by a largely local supply chain and by a similar number of admin staff in the main JFD head office. In a rescue the total number actively involved in the operation could range from 60-100 depending on the task.
With the NSRS, the UK has access to a world-leading rescue capability. Equipment is gradually improved and JFD are continually challenged to reduce response time and increase efficiency. By not being tied to a single ship and being air-portable, the system can be on-site and in action quickly when the clock is ticking on survival time for trapped submariners. Hopefully, NSRS will never be called upon for real but it remains the ultimate insurance policy for the submarine service.