Submarine escape training facility A Submarine Escape Training Tower is part of a facility used for training submariners in methods of emergency escape from a disabled submarine . It is a tall cylinder filled with water with several entrances at varying depths each simulating an airlock in a submarine . Since the 1930s Towers have been built for use by the Royal Navy , US Navy , Royal Australian Navy and in several other countries . Royal Navy SETT . The Submarine Escape Training Tank ( SETT ) is a deep facility primarily operated to conduct training with submarine escape equipment , operated by the Royal Navy . The facility , located at Fort Blockhouse , Gosport opposite HMNB Portsmouth , includes a fresh , chlorinated water column with a single escape chamber ( as fitted to some classes of RN submarines ) mounted at the base , through which students can conduct a fully representative escape cycle from , closely replicating actions which would be required if forced to abandon a distressed submarine from depth . The SETT has its own dedicated boiler house to maintain its water temperature at 34 °C ( 94 °F ) . The SETT was commissioned in 1954 , with the first students trained in July of that year . Since that time completion of ‘ the Tank ’ has been a rite of passage for all RN Submariners . Training includes ascents from increasing depths as a major element , but in addition is underpinned by lectures and practical training in how to survive within a disabled submarine , operation of emergency equipment and survival techniques on reaching the surface – a package of potentially life saving skills . Over the years , the SETT has been used to train submariners from Italy , USA , Greece , Canada , Israel , Russia , Venezuela , Turkey , Australia and the Netherlands – with the staff and facility enjoying a worldwide reputation for excellence and good practice . Owing to a combination of increased safety associated with modern submarine design , submarines operating in areas where escape would be impossible with current equipment and the risk associated with the conduct of training , the RN discontinued pressurised submarine escape training in March 2009 . The staff at RNSETT are drawn from the ranks of the UK Submarine Service . All members of SETT staff form part of the SMERAT ( Submarine Escape and Rescue Advisory Team ) , some members form the UK SPAG ( Submarine Parachute Assistance Group ) , and some form part of the UK contribution to the NSRS ( LR5 ) Team . All staff are trained in advanced life saving techniques and diving medicine . The tower was also privately hired to civilian diving clubs for the purpose of recreational diving and dive training . It is a popular ' novelty ' dive amongst UK SCUBA divers since it allowed new trainees to extend their depth experience in a safe , controlled environment with good visibility and warm water temperature – two conditions that are in short supply in the UK . For similar reasons it was also used for freediving training , with participants including world record holder Tanya Streeter . In addition , the SETT has been used frequently for both underwater equipment testing , and to support media activity – notably hosting Blue Peter on a number of occasions , with some presenters completing ascent training . It has also been used frequently as a Situation Assessment Trials Tank ( SATT ) for Technical Divers . Other facilities . The decommissioned tower on Ford Island , Hawaii , was built to train United States Navy Pacific Fleet submariners prior to World War II , and was converted for use as an airport control tower after the attack on Pearl Harbor . Across the harbor , the tower on Sub - Base Pearl Harbor was used between 1932 and 1983 . Neither of the U . S . escape towers in Hawaii are in use . The towers were also used to train SCUBA equipped divers ( SEALS ) or demolition teams to access or egress the submarine during Special Operations . The tower once located on Naval Submarine Base New London was in use between 1930 and 1994 and has since been razed . The Submarine Escape Trainer , a high , 84 , 000 - gallon pool was constructed at New London in 2007 . Similar facilities are operated by the Royal Australian Navy at the Submarine Escape Training Facility at , and in Norway , Sweden and Turkey at Gölcük Naval Base . The German Navy operates a 36 - metre deep escape training pool , built in 1977 , at Einsatzausbildungszentrum Schadensabwehr Marine ( Damage Control Training Centre ) in Neustadt in Holstein .