Date: 1960sDesigner: United States NavyCost: Undisclosed
The 1960s was a time of huge advancement in human exploration. But while the eyes of the headline writers were on Nasa's Apollo programme and events leading up to the lunar landings, nobody really noticed that the US Navy was pushing back another equally important frontier: the ocean depths.
While it was the space race that captured the public's imagination, the development of underwater habitats was accelerating, with research stations being built by scientists such as Jacques Cousteau. But it was the US Navy that led the way with its Sealab programme, which in three phases spanned most of the decade before its abrupt closure. The main purpose of the initial programme was to conduct research into the physiological aspects of saturation diving. The idea was that by providing divers with a pressurised subsea habitat, their ability to work underwater for longer periods would be increased, while the amount of time spent in decompression would be reduced.
Author Ben Hellwarth is one of the leading experts on Sealab, who describes the subsea modules as the marine equivalent of space stations, where "a gutsy group of US Navy divers and scientists forever changed man's relationship to the sub-aquatic world". Up until the 1960s conventional dives had strict depth limits, with divers only able to remain submerged for a matter of minutes. Sealab changed all that, with the window of opportunity for submersion extended to hours, days or even weeks.
The man behind the vision was George Bond, a retired doctor who had joined the Navy in the belief that there was a revolution waiting to happen in the world of deep-sea diving. It is thanks to Bond's pioneering spirit that divers in the offshore oil industry today, as well as scientists and military personnel, can spend extended time underwater.
Sealab I went into action off the coast of Bermuda in 1964, commanded by Bond, and reached a depth of 58m. Four divers were involved in the experiment, which lasted for 11 days and was brought to a close because of an impending tropical storm. The experiment was a success, with Bond showing that saturation diving in the open ocean was feasible for extended periods.
Sealab II was launched the following year in the La Jolla Canyon, California, to a depth of 62m. Considerably more advanced than its predecessor, Sealab II benefitted from hot showers and refrigeration and became known as the 'Tilton Hilton' on account of the slope of the landing site. Three teams of divers spent 15 days underwater, with aquanaut Scott Carpenter doing a double shift and setting a record of 30 days below. Work included research into heated dry suits as well as physiological testing and tool evaluation. The US Navy Marine Mammal Program supplied a bottlenose dolphin called Tuffy, who was employed to shuttle materials from the surface and to help with diver rescue should this become necessary. Tuffy's involvement was not an unqualified success and plans to include the cetacean in the next generation of Sealab activity were shelved.
Sealab III was built using the same structure as Sealab II, but was constructed in such a way that it could operate in water three times deeper. February 1969 saw the beginning of the project, which was to be shrouded in controversy and mystery. Soon after being lowered to the ocean floor off San Clemente technical problems occurred, and one of the four divers sent down died of carbon dioxide asphyxiation. Concern for diver safety prompted the Navy to scrap its seafloor habitat programme.
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