49th International Conference on Environmental Systems ICES-2019-323 7-11 July 2019, Boston, Massachusetts

Disabled Submarine Escape and Rescue Considerations

Stephanie M. Mohundro1 and Sara Jane Neal 2

Naval Sea Systems Command, Washington Navy Yard, DC 20316, USA12

Abstract HE United States Navy’s (USN) submarine escape and rescue program supports US and foreign submarine T services by providing the essential capability to rescue sailors at depth in the event of a distressed submarine (DISSUB) event, as demonstrated in support of the loss of the Argentinian submarine ARA SAN JUAN in November 2017. The USN operates the Submarine Rescue Diving and Recompression System (SRDRS) and the Submarine Rescue Chamber Fly-away System (SRCFS) for deep and shallow water rescue. As a result of the lessons learned from exercises as well as the ARA SAN JUAN events, the program is actively pursuing technology improvements to address shallow water rescue capability gaps, enhance survivability challenges of DISSUB sailors, maintain efficiency, and increase international engagements.

While maintaining existing rescue readiness, the final manned testing and certification of the Submarine Decompression System (SDS) will be completed; delivering to the fleet the ability to recover and medically treat sailors from a pressurized DISSUB. While the delivery of the SDS system will significantly advance the USN rescue capabilities, additional techonology improvements are still required to ensure a robust and sustainable submarine escape and program.

This paper will serve to update government and industry partners on the status of our capabilities, current acquisitions and procurements, highlights of recent exercises, their pertinent lessons learned, and to share perspectives on future technology objectives with emphasis on environmental systems.

I. Background Submarine Escape and Rescue has long been an integral part of the overall USN undersea warfare (USW) enterprise. Due to numerous submarines sinking with survivors that perished on board the vessels with no way off, the Submarine Escape and Rescue (SER) program was established in the beginning of the 20th century to provide the capability to rescue survivors of a DISSUB. The capability was validated during the successful response to the USS SQUALUS on 23 May 1939 when the SRC saved thirty-three submariners of the 310-foot boat from a depth of 240 feet. Due to flooding in the aft compartment, twenty-four sailors and two civilians died, but using the Momsen- McCann rescue chamber provided by the Washington Navy Yard-based Experimental Diving Unit, thirty-two sailors and one civilian were successfully brought to the surface. The evolution was accomplished in four trips spanning thirty-nine hours from the time the submarine initially sank.

While the USS SQUALUS is considered to be the only successful rescue of a USN DISSUB, submarining is a dangerous business as illustrated by the near misses of the USS SAN FRANCISCO (2005), USS GREENVILLE (2001), and USS MONTPELIER (2012), the sinking of the RN Kursk in 2000 and most recently of the loss of the ARA SAN JUAN with all personnel in November 2017. As one of only four flyaway submarine rescue systems globally, the USN submarine escape and rescue program is a humanitarian-focused avenue that provides safety to USN submarine sailors as well as partner-nation submarine sailors. Beyond the singular event of the loss of the ARA SAN JUAN, partnerships with other nations are continually being fostered and new ones founded. Through partnership with the NATO Submarine Escape and Rescue Working Group (SMERWG), the Asia Pacific Submarine Conference (APSC), Diesel Submarine Initiative (DESI) and several others, the USN submarine escape and rescue program continues to expand its global footprint to ensure DISSUB survivors can be rescued across the globe.

1 Stephanie M. Mohundro, Submarine Escape and Rescue Research and Development. 2 Sara Jane Neal, Technical Warrant Atmosphere Control

Copyright © 2019 Naval Sea Systems Command

II. Submarine Escape and Rescue Integrated Capabilities

The SER program focuses on four separate pillars that establish the four specific technology areas focused on accomplishing the successful retrieval of survivors of a DISSUB event. These four pillars are: (1) Alertment, search and localization of a DISSUB; (2) Onboard DISSUB survival of personnel; (3) Escape of survivors at depth to the surface; and (4) Rescue of personnel from depth to the surface.

Alertment, Search and Localization. Alertment of a DISSUB is accomplished on USN submarines by the launch of a Submarine Emergency Positioning Indicator Radio Beacon (SEPIRB) by DISSUB survivors. Each submarine compartment has two SEPIRBS that are passively launched from either the forward or aft compartments to identify to rescue forces that a submarine is in distress and requires assistance. Figure 1. Submarine Emergency Positioning Indicator Radio Beacon Once alerted, the search and localization of the DISSUB by rescue forces is accomplished by surface and subsea equipment to establish a datum point for the DISSUB. The SER program mobilizes the Assessment Underwater Work System (AUWS), which is comprised of a medium-weight Remotely Operated Vehicle (ROV) SIBITSKY. In addition to providing localization of the DISSUB, the SIBITSKY also is responsible for hatch and debris clearance, establishing communications if able, and providing intervention if necessary. The ROV operates to 2000 feet of sea water to support the deep water rescue requirements. Figure 2. SIBITZKY ROV. DISSUB Survival. In the case of a DISSUB event, it is anticipated that there will be a loss of normal power and therefore a loss of normal operations of atmospheric and environmental control. Survivors will have to rely on available emergency battery capabilities and passive technologies to provide Carbon Dioxide (CO2) scrubbing, Oxygen (O2) generation, and contaminant, humidity and temperature control. Space available onboard precludes the ability for these measures to be large and physiological constraints preclude the ability to require high levels of manpower to operate. The short-term and long- term effects of personnel subjected to increased pressures while awaiting rescue or sustained exposure to atmospheric contaminants is also a concern. The decision to escape versus await rescue is a result of atmospheric and environmental conditions onboard the DISSUB degrading significantly to the point that the Senior Survivor has determined the risks of awaiting rescue are higher than attempting escape. All USN submarines are outfitted with passive CO2 removal curtains and O2candles to provide atmosphere control. There are sufficient quantities of CO2 curtains and O2 candles to support seven days of survivability for a full submarine crew complement. Beyond the removal of CO2 and the introduction of O2, USN has limited means of passively removing atmospheric contaminants. The Senior Survivor uses Guard Books to monitor the atmosphere of the Figure 3. Left, CO2 Curtains. Right, Oxygen Candles. DISSUB and colormetric tubes to determine the toxicity levels of Top, Guard Book. constituents, with the primary focus on seven Submarine Escape Action Limit (SEAL) gases. The seven SEAL gases are Carbon Monoxide, Hydrogen Cyanide, Ammonia, Chlorine, Hydrogen Chloride, Sulfur Dioxide, and Nitrogen Dioxide; these specific contaminants have been identified as the most likely atmospheric contaminants resulting from a DISSUB event. Each SEAL gas has two specific thresholds (SEAL Level 1 and SEAL Level 2) that are monitored to identify when escape must be attempted to support survival of personnel during the escape sequence and once on the surface. In the event the SEAL Level 1 of a particular SEAL gas, is approaching or has been met, all survivors

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will don the Emergency Air Bib (EAB) and commence escape, such that all personnel have escaped (or been rescued) prior to the SEAL Level 2 limit(s) being met. While reasonably accurate at surface pressure, i.e. 1 atmosphere absolute (ATA), internal navy testing has identified that the accuracy and precision of colormetric tubes to provide toxicity levels at higher pressures, i.e. greater than 1 ATA, may be degraded. At this time, however, currently developed technology precludes the ability to provide more accurate capabilities.

With the exception of monitoring and controlling the atmosphere during a DISSUB event, any additional actions on the part of the DISSUB crew are kept at a minimum to reduce the physiological effects of the confined and austere environment while awaiting rescue.

Escape. All USN submarines are outfitted with Submarine Escape and Surface Survival Protection Equipment (SESSPE) suits that allow for escape from a submarine down to 600 fsw. The equipment itself can support escape to deeper depths; however, there is high likelihood of death. Two survivors can escape per cycle via each Figure 4. Submarine Escape and Surface Survival Protection Equipment. escape trunk by charging the escape trunk with air from regulators prior to flooding the trunk and opening the upper hatch. The trapped air within the suit provides positive buoyancy and breathable air to the escaper until reaching the surface. Once on the surface and self-contained, single-man liftraft can be inflated via a compressed CO2 cylinder, allowing for a minimum of 24 hours of surface survivability. The rapid flood-up time reduces the risks associated with decompression obligations once at the surface. However, due to the higher risk, rescue is the primary procedure used for USN submarines.

Rescue. Awaiting rescue is considered to be the primary method to leave a USN DISSUB. The US has two rescue systems, operated by the Undersea Rescue Command (URC) based at NAS North Island in San Diego, California.

The shallow water system for the USN is the Submarine Rescue Chamber (SRC) initially designed in the 1930’s by the Navy’s Experimental Diving Unit. The SRC is a fly-away system capable of providing rescue of 8 survivors per sortie to a depth of 850 fsw at 1 ata and is continuously ventilated from the surface via umbilical hoses. After a down-haul cable is connected to the DISSUB hull, the chamber is driven from the surface to the DISSUB via an air ratchet system. The rescue chamber mates to the DISSUB escape hatch where the water in the lower compartment is pumped to the chamber’s ballast tanks to create a differential pressure seal. The pressurized air in the ballast tanks is then vented into the upper compartment and then to the surface via the exhaust hose. Once vented, the chamber and the DISSUB can equalize and the upper hatch of the DISSUB can be opened allowing for survivors to exit the DISSUB and enter the chamber for transport to the surface. The USN currently maintains and operates two SRCs as part of the submarine rescue program.

Deep water, pressurized rescue is accomplished via the Submarine Diving and Recompression System (SRDRS). Designed with two configurations, the Submarine Rescue System – Rescue Capable System (SRS-RCS) is used for unpressurized training Figure 5. Submarine Rescue and the Submarine Rescue System – Transfer Under Pressure (SRS-TUP) provides actual Chamber. submarine rescue to an internal DISSUB pressure of up to 5 ATA and to a submerged depth of up to 2000 fsw. Both configurations are fly-away systems via a combination of C-17’s and C-5’s and designed to be mobilized onboard a commercial or military Vessel of Opportunity (VOO).

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The Pressurized Rescue Module (PRM) of the SRDRS is a remotely operated vehicle with the capacity to hold 18 personnel, 16 rescuees and 2 internal attendants, per sortie. The internal attendants are responsible for creating a seal with the DISSUB, monitoring life support internal to the PRM, and providing assistance to the rescues while transiting to the surface. The PRM is designed with an active life support system. The active life support is provided by six fan-powered CO2 scrubbers using Sofnolime granules and a high-pressure O2 bleed to provide to metabolic make- up. In addition to cabin air, the PRM is outfitted with a closed-circuit Emergency Breathing System (EBS) in the event the cabin atmosphere is contaminated. There are 20 EBS masks installed. In the event of loss of power from the umbilical, the onboard emergency batteries can maintain emergency life support to the cabin for 18 hours with a full complement of 18 personnel. In addition to CO2 scrubbing and O2 bleed, the PRM has a baffle forced-air environmental control system to maintain the internal temperature and humidity.

SRS-TUP provides a full end-to-end pressurized rescue of DISSUB survivors up to 5 ATA. There is a high likelihood that pressurized rescue would be required in a DISSUB event as a result of flooding or airbank usage and thus saturation of survivors will occur within 60 minutes at 60 fsw. This will increase the risk of decompression obligations once the survivors are Figure 6. PRM on VOO during deployment process. transported to the surface. The TUP complex, comprised of two Submarine Decompression Chambers (SDCs), flexible manways, and medical transport locks (MTLs), provides the ability to transfer rescued personnel from the PRM to the SDCs under pressure. Once entering the complex, rapid depressurization treatment can be administered for up to 62 rescuees at a time, with each SDC also internally monitored by two internal attendants. Decompression tables have been developed to provide air decompression from 5 ATA of one person in 52 hours or O2 decompression of one person in 32 hours. If further treatment is required, survivors can be locked out in the MTLs, and each MTL can support one rescuee and one attendant. Similar to the PRM, life support is provided to the SDCs and the MTLs via fan-powered CO2 scrubbing and O2 bleed to provide metabolic makeup. High pressure O2 and Air is supplied by gas racks that are mobilized with the SRDRS system. Both the Air and O2 gas cylinders are capable of being charged via an LP Air compressor and an O2 booster pump if required.

In addition to the PRM and the TUP complex, additional equipment is mobilized to support rescue operations. This includes the PRM Launch and Recovery System, the Control Van, the Deck Cradle, Ship Interface Templates, and various other Mission Support Equipment.

III. Tragic loss of the ARA SAN JUAN, USN SER Response, and Lessons Learned

In November 2017, the ARA SAN JUAN was lost at sea off of the coast of the Falkland Islands in southern Argentina. During a transit north back to the ship’s homeport, a battery casualty was reported by the submarine. The last known position of the ship was on 15 November 2017 and assistance for search and rescue was requested from the USN by the Argentinian government. Due to the limited time available to any DISSUB survivors, URC, along with other search assets from USN, NASA, and WHOI, were immediately mobilized to render search and rescue aid. Equipment and personnel mobilized from URC included the SRDRS, the SRC, the ROV, side-scan sonars and Unmanned Underwater Vehicles. Via 5 C-17s and 3 C-5’s, 365 tons of equipment and 200 personnel were transported from the US to the rescue port located in Comodoro Rivadavia (CR) Argentina. All rescue equipment was mobilized onboard three commercial ships, the Skandi Patagonia, the Sophie Siem and the DIDI K, all of which had Figure 7. Pressurized Rescue Module. never been utilized before. Search and rescue efforts were performed from 17 4 International Conference on Environmental Systems

November to 01 December, at which time rescue efforts were suspended due to the fact that onboard survival stores would have been expended. The ARA SAN JUAN was ultimately found by commercial search equipment on 16 November 2018 at a depth of approximately 3,000 feet. Search and recovery efforts continued until 28 December 2017. Visual confirmation indicated that the submarine suffered an implosion.

Following the loss of the ARA SAN JUAN, the greater USN submarine force reviewed the response by the USN submarine rescue program to identify lessons learned and lessons identified for both implementation domestically and to provide to partner nations. Those lessons continue to be revisited, refined and further implemented to ensure that the submarine rescue program continues to provide the highest level of support in the event of a DISSUB as possible.

Specific to the ARA SAN JUAN, a key takeaway for the search, rescue and recovery response is focused on the challenges associated with quickly identifying the location of the DISSUB when prior cueing or information is Figure 8. Search Area off Argentine Coast. forthcoming. Most submarines, regardless of the country, are outfitted with some emergency life support stores that are to be used only if survivors are confined to an austere environment awaiting rescue. The amount of emergency life support stores that are provided is typically calculated to coincide with the compartment size of the vessel, the number of riders, and range. USN submarines get underway with a minimum of 7 days of emergency life support stores.

The extreme distance to the rescue port and the weather played a key role in the amount of time required to mobilize rescue forces and contact search operations. While the first air transport landed in Comodoro Rivadavia, Argentina 43 hours after the Notice to Mobilize (NTM), the SRC was mobilized and underway within 96 hours, and the remainder of the necessary equipment, to include the Pressurized Rescue Module, was mobilized within 120 hours, which was 168 hours after the last known communications.

IV. Conclusion: Survival in Confined, Extreme and Austere Environments and Technology Objectives

The ability to survive in and rescue personnel from confined, extreme and austere environments provides unique challenges that are not seen in normal operations. Space constraints, limited prior information, and acknowledgement of the risks to rescue forces further complicates these challenges.

While historically the USN submarine force has established the requirement for 7 days of emergency life support stores on all USN submarines, review of the lessons learned has identified that additional means to control the DISSUB atmosphere may be required. Initiatives by the Submarine Escape and Rescue Research and Development program have been established to address this. These initiatives include research in the ability to provide passive depressurization of the DISSUB while awaiting rescue, the ability to provide more accurate measurement and monitoring of atmospheric contaminants under pressure, the ability to provide increased efficiency of CO2 scrubbing and the ability to provide scrubbing of the 7 SEAL gas contaminants, to name a few. Additionally, with the acknowledgement of the expertise resident across multiple organizations with similar mission profiles, the Submarine Escape and Rescue program has begun to establish a consortium to promote knowledge sharing and information.

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ABBREVIATIONS / ACRONYMS

APSC Asia Pacific Submarine Conference ATA Atmospheres Absolute AUWS Assessment/ Underwater Work System CO2 Carbon Dioxide CR Comodoro Rivadavia DESI Diesel Submarine Initiative DISSUB Disabled Submarine EAB Emergency Air Bib EBS Emergency Breathing Apparatus MTL Modified Transfer Lock NTM Notice to Mobilize O2 Oxygen PRM Pressurized Rescue Module ROV Remotely Operated Vehicle SDC Submarine Decompression Chamber SDS Submarine Decompression System SEAL Submarine Escape Action Limit SEPIRB Submarine Emergency Position Indicating Radio Beacon SER Submarine Escape and Rescue SESSPE Submarine Escape and Surface Survival Protection Equipment SMERWG Submarine Escape and Rescue Working Group SRC Submarine Rescue Chamber SRCFS Submarine Rescue Chamber Fly-away System SRDRS Submarine Rescue Diving and Recompression System SRS-RCS Submarine Rescue System – Rescue Capable System SRS-TUP Submarine Rescue System – Transfer Under URC Undersea Rescue Command USN United States Navy USW Undersea Warfare VOO Vehicle of Oppurtunity

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