Compagnie maritime d'expertises

{{Short description|French offshore diving contractor}}

File:Comex diving sphere mg 6143.jpg]]

COMEX (or Compagnie Maritime d'Expertises) is a French company specializing in engineering and deep diving operations, created in November 1961 by Henri-Germain Delauze and run by him until his death in 2012.

This company is known worldwide for its technology in regard to underwater exploration at great depths.{{citation needed|date=April 2020}}

Its line of business includes:{{citation needed|date=April 2020}}

• hyperbaric testing facilities,
• oceanographic research ships (Minibex and Janus),
• testing pool.{{clarify|date=April 2020}}

COMEX carried out pioneering work in very deep saturation diving. The company experimented with the use of hydrogen in the divers' breathing gas.

This work with heliox (a breathing gas mixture of helium and oxygen) and hydreliox (an exotic breathing gas mixture of helium, oxygen and hydrogen gas) mixtures started with Hydra I in 1968. The saturation diving physiology studies were conducted with helium from {{convert|45|to|610|m|ft|abbr=on}} and with hydrogen from {{convert|70|to|701|m|ft|abbr=on}}. The diving depth record for off-shore (saturation) diving was achieved in 1988 by a team of COMEX professional divers (Th. Arnold, S. Icart, J.G. Marcel Auda, R. Peilho, P. Raude, L. Schneider) performing pipe line connection exercises at a depth of {{convert|534|m|ft|abbr=on}} of seawater (msw/fsw) in the Mediterranean Sea, whist breathing a hydreliox mixture, as part of the Hydra VIII (Hydra 8) programme.{{cite web |url=http://www.comex.fr/suite/ceh/histo/histo%20anglais.html |title=Extreme Environment Engineering Departement Hyperbaric Experimental Centre - History |access-date=2009-02-22 |url-status=dead |archive-url=https://web.archive.org/web/20081005073910/http://www.comex.fr/suite/ceh/histo/histo%20anglais.html |archive-date=October 5, 2008 }} The Hydra programme culminated with Hydra X (Hydra 10) in 1992 when COMEX diver Théo Mavrostomos achieved a record simulated dive of {{convert|701|m|ft|abbr=off}} in an onshore hyperbaric chamber.{{cite web|url=http://gtuem.praesentiert-ihnen.de/tools/literaturdb/project2/pdf/Gardette%20B.%20-%20EUBS%201993%20-%20S.%2032.pdf|title=Hydra 10 : a 701 msw onshore record dive using "hydreliox"}}[https://www.newscientist.com/article/mg13618493.000 Technology: Dry run for deepest dive, New Scientist 28 November 1992]{{cite journal |vauthors=Lafay V, Barthelemy P, Comet B, Frances Y, Jammes Y |title=ECG changes during the experimental human dive HYDRA 10 (71 atm/7,200 kPa) |journal=Undersea and Hyperbaric Medicine |volume=22 |issue=1 |pages=51–60 |date=March 1995 |pmid=7742710 |url=http://archive.rubicon-foundation.org/2203 |access-date=2009-02-22 |archive-url=https://web.archive.org/web/20110811174923/http://archive.rubicon-foundation.org/2203 |archive-date=2011-08-11 |url-status=usurped }}{{cite web|publisher=Comex S.A. |title=HYDRA 8 and HYDRA 10 test projects |url=http://www.comex.fr/suite/ceh/histo/histo%20anglais.html |access-date=2009-02-22 |url-status=dead |archive-url=https://web.archive.org/web/20090105233813/http://www.comex.fr/suite/ceh/histo/histo%20anglais.html |archive-date=January 5, 2009 }}

The use of hydrogen for diving was in part driven by the need to overcome the problems of high-pressure nervous syndrome (HPNS). However, there was another reason for the interest in using hydrogen in a breathing gas. In 1987, Comex was part of a Canadian-French consortium that was building the world’s first commercial nuclear mini-submarine. This submarine, Saga, was a prototype intended to be used for oil exploration and development under the Arctic ice. Saga was built on a hull originally constructed by Jacques-Yves Cousteau but not completed due to lack of funds. Saga would have a complete saturation diving system on board. The nuclear power plant would be able to produce large volumes of hydrogen and oxygen through the electrolysis of water. This would provide plentiful amounts of breathing gas for autonomous diving operations under the Arctic ice cap.

The project suffered tax problems in Canada which caused political repercussions between the French and Canadian governments.{{Cite web|url=https://www.cns-snc.ca/branches/quebec/saga_n/SAGA_N.html|title=Submarine project in dispute France, Canada clash over firm's unpaid taxes|last=Moon|first=Peter|date=1 July 1987|publisher=The Globe and Mail|archive-url=https://web.archive.org/web/20040621200312/http://www.cns-snc.ca/branches/quebec/saga_n/SAGA_N.html|archive-date=2004-06-21|url-status=dead}} Saga did undergo successful sea trials in 1991 but without the intended nuclear power plant. Underwater propulsion was provided by a Stirling engine and surface propulsion by a diesel engine.{{Cite web|title=WTEC: Reports|url=http://scienceus.org/wtec/|access-date=2021-05-08|website=scienceus.org}} The project was abandoned and Saga was laid up at Marseille.