
A Submarine Escape Training Tower is a facility used for training submariners in methods of emergency escape from a disabled
submarine
A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or infor ...
underwater. It is a deep tank filled with water with at least one underwater entrance at depth simulating an
airlock
An airlock is a room or compartment which permits passage between environments of differing atmospheric pressure or composition, while minimizing the changing of pressure or composition between the differing environments.
An airlock consist ...
in a submarine. Since the 1930s, towers have been built for use by the
Royal Navy
The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
,
US Navy
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
,
Royal Australian Navy
The Royal Australian Navy (RAN) is the navy, naval branch of the Australian Defence Force (ADF). The professional head of the RAN is Chief of Navy (Australia), Chief of Navy (CN) Vice admiral (Australia), Vice Admiral Mark Hammond (admiral), Ma ...
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
Fort Blockhouse is a former military establishment in Gosport, Hampshire, England, and the final version of a complicated site. At its greatest extent in the 19th century, the structure was part of a set of fortifications which encircled much ...
,
Gosport
Gosport ( ) is a town and non-metropolitan district with Borough status in the United Kingdom, borough status in Hampshire, England. At the 2021 United Kingdom census, 2021 Census, the town had a population of 70,131 and the district had a pop ...
opposite
HMNB Portsmouth
His Majesty's Naval Base, Portsmouth (HMNB Portsmouth) is one of three operating bases in the United Kingdom for the Royal Navy (the others being HMNB Clyde and HMNB Devonport). Portsmouth Naval Base is part of the city of Portsmouth; it is loc ...
,
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 risks associated with the conduct of training, the RN discontinued pressurised submarine escape training in March 2009.
The staff at SETT 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
The Royal Navy's Submarine Parachute Assistance Group (SPAG) is a team who provide a rescue support capability to submarine sinking incidents worldwide, available at short notice.
History
The Submarine Parachute Assistance Group was originally ...
),
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.
Other uses

The tower was also privately hired to civilian diving clubs for the purpose of recreational diving and dive training. It was a popular 'novelty' dive amongst UK
scuba divers
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The word ''scuba'' is an acronym for ...
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
Freediving, free-diving, free diving, breath-hold diving, or skin diving, is a mode of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear.
Besides the limits of breat ...
training, with participants including world record-holder
Tanya Streeter
Tanya Streeter (born Tanya Dailey, 10 January 1973, Grand Cayman) is a British-Caymanian-American world champion freediver, inducted into the Women Divers Hall of Fame in March 2000.
For more than two months, from 17 August 2002, she held the ...
. In addition, the SETT has been used frequently for both underwater equipment testing, and to support media activity – notably hosting
Blue Peter
''Blue Peter'' is a British children's television entertainment programme created by John Hunter Blair. It is the longest-running children's TV show in the world, having been broadcast since October 1958. It was broadcast primarily from BBC ...
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.
US Navy
US Navy escape towers were known as Escape Training Tanks. From the 1930s through the 1990s, they were used for training in
buoyant ascent, the
Momsen lung
The Momsen lung was a primitive underwater rebreather used before and during World War II by American submariners as emergency escape gear. It was invented by Charles Momsen, who worked on it from 1929 to 1932. Submariners trained with this appar ...
, and the
Steinke hood
A Steinke hood, named for its inventor, Lieutenant Harris Steinke, is a device designed to aid escape from a sunken submarine. In essence, it is an inflatable life jacket with a hood that completely encloses the wearer's head, trapping a bubble ...
. The decommissioned tower on
Ford Island
Ford Island () is an islet in the center of Pearl Harbor, Oahu, in the U.S. state of Hawaii. It has been known as Rabbit Island, Marín's Island, and Little Goats Island; its native Hawaiian name is ''Mokuumeume''. The island had an area of ...
,
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
, was built to train
United States Navy
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
Pacific Fleet submariners prior to
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
, and was converted for use as an
airport control tower
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...
after the
attack on Pearl Harbor
The attack on Pearl HarborAlso known as the Battle of Pearl Harbor was a surprise military strike by the Empire of Japan on the United States Pacific Fleet at Naval Station Pearl Harbor, its naval base at Pearl Harbor on Oahu, Territory of ...
.
Across the harbor, the tower on Sub-Base
Pearl Harbor
Pearl Harbor is an American lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. It was often visited by the naval fleet of the United States, before it was acquired from the Hawaiian Kingdom by the U.S. with the signing of the Reci ...
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
Scuba, originally SCUBA, often expanded to scuba set, is any self contained underwater breathing apparatus, a source of breathing gas used for underwater diving which is carried by the diver.
Scuba may also refer to:
* Scuba diving, swimming unde ...
equipped divers (
SEAL
Seal may refer to any of the following:
Common uses
* Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly:
** Earless seal, also called "true seal"
** Fur seal
** Eared seal
* Seal ( ...
s) or
Underwater Demolition Team
The Underwater Demolition Team (UDT), or frogmen, were amphibious units created by the United States Navy during World War II with specialized missions. They were predecessors of the Navy's current United States Navy SEAL, SEAL teams.
Their pri ...
s to access or egress the submarine during special operations. The tower once located on
Naval Submarine Base New London
Naval Submarine Base New London is the primary United States Navy East Coast submarine base, also known as the "Home of the Submarine Force." It is located in Groton, Connecticut directly across the Thames River from its namesake city of New L ...
was in use between 1930 and 1994 and has since been razed. The Submarine Escape Trainer, a high, 84,000-gallon pool with two
escape trunk
Escape or Escaping may refer to:
Arts and media Film
* ''Escape'' (1928 film), a German silent drama film
* ''Escape!'' (film), a 1930 British crime film starring Austin Trevor and Edna Best
* ''Escape'' (1940 film), starring Robert Taylor and ...
s was constructed at New London in 2007.
Other facilities

Similar facilities are operated by the Royal Australian Navy at the
Submarine Escape Training Facility
A Submarine Escape Training Tower is a facility used for training submariners in methods of emergency escape from a disabled submarine
A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It di ...
at , in Norway and Sweden, and in Turkey at
Gölcük Naval Base. The
German Navy
The German Navy (, ) is part of the unified (Federal Defense), the German Armed Forces. The German Navy was originally known as the ''Bundesmarine'' (Federal Navy) from 1956 to 1995, when ''Deutsche Marine'' (German Navy) became the official ...
operates a 36-metre-deep escape training pool, built in 1977, at Einsatzausbildungszentrum Schadensabwehr Marine (Damage Control Training Centre) in
Neustadt in Holstein
Neustadt in Holstein (; Holsatian: ''Niestadt in Holsteen'') is a town in the district of Ostholstein, in Schleswig-Holstein, Germany, on the Bay of Lübeck 30 km northeast of Lübeck, and 50 km southeast of Kiel.
History
In World War ...
.

Since 2013 there is a submarine escape training tank situated next to non-profit swimming pool ''
Het Heersdiep'' in
Den Helder
Den Helder () is a municipality and a city in the Netherlands, in the province of North Holland. Den Helder occupies the northernmost point of the North Holland peninsula. It is home to the country's main naval base.
From here the Royal TESO fe ...
, The
Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...
. This tank is used by the
Royal Netherlands Navy
The Royal Netherlands Navy (, ) is the Navy, maritime service branch of the Netherlands Armed Forces. It traces its history to 8 January 1488, making it the List of navies, third-oldest navy in the world.
During the 17th and early 18th centurie ...
and also by other navies from all over the world. The tower at Aquacentrum Den Helder can also be used by civilian diving clubs for recreational diving and dive training. It is also used for
freediving
Freediving, free-diving, free diving, breath-hold diving, or skin diving, is a mode of underwater diving that relies on breath-holding until resurfacing rather than the use of breathing apparatus such as scuba gear.
Besides the limits of breat ...
training and for fire brigade diving training.
The
South African Navy
The South African Navy (SA Navy) is the naval warfare branch of the South African National Defence Force.
The Navy is primarily engaged in maintaining a conventional military deterrent, participating in counter-piracy operations, fishery prote ...
has a submarine escape training tank at the navy diving school at the
SAS Simonsberg
SAS or Sas may refer to:
Military
* Special Air Service, a special forces unit of the British Army
* Special Air Service Regiment, a special forces unit of the Australian Army
* 5th Special Air Service, a Belgian Second World War formation
* ...
training unit in
Simon's Town
Simon's Town (), sometimes spelled Simonstown, is a town in the Western Cape, South Africa and is home to Naval Base Simon's Town, the South African Navy's largest base. It is located on the shores of Simon's Bay in False Bay, on the eastern s ...
on the Cape Peninsula.
References
External links
''Rescue Tank May End Sub Deaths'', November 1930, Popular Science– two-page 1930 article on the new US Navy SETT in New London, Connecticut
Royal Navy Submarine School (RNSMS)Submarine Escape Training Tank– Royal Navy website
International Submarine Escape & Rescue Office*
Dutch International Submarine Escape & rescue Training TRITON12
{{authority control
Royal Navy bases in Hampshire
Freediving
Underwater diving sites
Underwater diving procedures