Submarine Escape Immersion Equipment Submarine Escape Immersion Equipment ( SEIE ) MK - 10 , also known as Submarine Escape " and " Immersion Equipment is whole - body suit and one - man life raft , designed by British company RFD Beaufort Limited , that allows submariners to escape from a sunken submarine . The suit provides protection against hypothermia and is rapidly replacing the Steinke hood rescue device . The suit allows survivors to escape a disabled submarine at depths down to , at a rate of eight or more men per hour . RFD Beaufort has pioneered the development of Submarine Escape Technology from the 1950s and has set the global standard for submarine escape . The latest generation RFD Beaufort SEIE MK11 enables free ascent from a stricken submarine and provides extensive protection for the submariner on reaching the surface until rescued . Since 1994 over 25 , 000 SEIE suits have been supplied to over 20 navies . A typical assembly comprises a submarine escape and immersion suit , an inner thermal liner , and a gas - inflated single - seat life raft , all contained in an outer protective stowage compartment . The suit not only keeps the escapee dry and protected from cold shock during escape , but also acts as a thermally efficient immersion suit on reaching the surface . Full protection is therefore provided while deploying and boarding the life raft . The suit provides sufficient lifting force to take the escapee from the submarine to the surface at a safe speed of approximately two to three meters per second . The SEIE Mk - 10 has been used in Royal Navy Submarines for a number of years . The SEIE MK - 10 is scheduled to replace all Steinke hoods aboard U . S . Navy submarines . The reconfiguration of escape trunk s and training of the crews are requirements prior to installing the new system and several submarines have already installed the new system . The Steinke hood was designed for the same circumstances , but did not include a full - body , thermally insulated suit or life raft . It was at best a last - ditch survival device but would not protect submariners from hypothermia or provide shelter or visibility at the surface , as the SEIE is designed to do . In the event of an emergency , the SEIE might save submariners from death . However , the device is designed to be a last resort in the event of a submarine emergency at sea . The goal in the event of a submarine mishap is survival . The second is rescue with a submarine rescue vehicle . Lastly , if a rescue vehicle is not available or cannot connect to a stricken submarine , the crew can escape using the SEIE . Optimally , a rescue vehicle is preferred as it allows crewmembers to survive with essentially no injuries since they are protected from the great amount of pressure at ocean depths . A rescue vehicle connects directly to the escape hatch of a submarine , eliminating the threat of exposure to cold water and extreme pressure . In addition , the primary benefit of rescue before resorting to escape with the SEIE is that there would be resources available , including a recompression chamber , should it be needed by the rescued crew members . However , unlike the Steinke Hood , the suit provides good protection from decompression sickness , hypothermia , and climatic exposure .