Anaquanaut is any person who remains underwater, breathing at the ambientpressure for long enough for the concentration of theinert components of thebreathing gas dissolved in the body tissues to reachequilibrium, in a state known assaturation.
The termaquanaut derives from the Latin wordaqua ("water") plus the Greeknautes ("sailor"), byanalogy to the similar construction "astronaut." The word is used to describe a person who stays underwater, breathing at the ambientpressure for long enough for the concentration of the inert components of the breathing gas dissolved in the body tissues to reach equilibrium, in a state known as saturation. Usually this is done in anunderwater habitat on theseafloor for a period equal to or greater than 24 continuous hours without returning to the surface.[1][2][3]
The term is often restricted to scientists and academics, though there were a group of military aquanauts during theSEALAB program.Commercial divers in similar circumstances are referred to assaturation divers. An aquanaut is distinct from a submariner, in that a submariner is confined to a moving underwater vehicle such as asubmarine that holds the water pressure out.[1][2][3]
From 1969 to 1970,NASA carried out two programs, known as Tektite I and Tektite II, using theTektite habitat. Missions were carried out in which scientists stayed in the capsule for up to 20 days, in order to study fish ecology as well as to prove thatsaturation diving techniques in an underwater laboratory, breathing a nitrogen-oxygen atmosphere, could be safely and efficiently accomplished at a minimal cost.[7][8] Tektite II also studied the psychological aspects of living in such confinement.[8]
A unit of theRussian Navy has developed an aquanaut program that has deployed divers more than 300 metres (980 ft) deep. An ocean vessel has been developed and is based inVladivostok that is specialized for submarine and other deep sea rescue and that is equipped with a diving complex and a 120-seat deep sea diving craft.[10]
A Nigerian ship's cook, Harrison Odjegba Okene, survived for 60 hours in a sunkentugboat, theJascon-4, which had capsized on 26 May 2013 due to rough seas while performing tension tow operations and stabilising anoil tanker at aChevron platform in theGulf of Guinea off the Nigerian coast.[11] After sinking, the boat came to rest upside-down on the sea floor at a depth of 30 m (98 ft); eleven crew members perished. As theJascon-4 filled with water, Okene had felt around the interior underwater and found his way into theengineer's office, where he found an air pocket about 1.2 m (3 ft 11 in) in height that contained enough oxygen to keep him alive.[12][13][14][15]
Three days after the accident, Okene was discovered by three South African divers from a saturation diving support vessel, employed to investigate the sunken ship and recover bodies. Having unintentionally discovered Okene alive within the ship, the rescuers provided him with adiving helmet so he could breathe during the transit to thediving bell. He was then returned to the surface afterdecompression fromsaturation, which took about two and a half days.[11][16] After his survival underwater, he faced and overcame hispsychological trauma and later became a commercial diver himself, earning anInternational Marine Contractors Association recognisedClass 2 certificate.[17]
^Davis, Michael (1979)."Immersion hypothermia in scuba diving".South Pacific Underwater Medicine Society Journal.9 (2). Archived from the original on 13 January 2013. Retrieved14 April 2013.
Flemming, N. C.; Max, M. D. (eds.).Code of Practice for Scientific Diving: Principles for the Safe Practice of Scientific Diving in Different Environments. UNESCO Technical Papers in Marine Science 53.
