Developed in conjunction with Comex and the legendary Jacques Cousteau, Omega conceived and developed what was probably the first waterproof watch designed and built solely for the diving professional.
The watch took 4 years to come to the market after extensive testing and arrived in 1970. It was nicknamed PloProf by the French speaking development team and derives from the French term PLOngeur PROFessionnel (Professional Diver).
Comex used early models of the PloProf and continued their research into living underwater for prolonged periods. One Issue that still concerned Comex was helium infiltration, which carried the danger of causing a watch crystal to pop out during decompression.
There is no proof that this problem occurred with any Ploprof, and later tests by the American diving research centre Ocean Systems Inc. in Tarrytown, NY, certified that the Ploprof was ‘more watertight’ than a submarine. However, Comex wanted to be sure to combat the helium infiltration issue, rather than trust improved watch-case sealing. They chose to continue their research work with Rolex and Doxa to test their new Helium Expulsion Valve (HEV) designs. HEVs were incorporated in the Rolex SeaDweller which Comex used reliably for many, many years.
During the 4 year gestation period the PloProf was tested to 600m at the Omega factory and to 1000m in the Gulf of Lion, off the coast of Marseilles. It was used by Commander Jacques Cousteau during his series of experiments designed to test man's physical and psychological capacities when working at depths of 500m.
During ‘operation Janus’ in 1970 3 Comex divers wore the watch at a depth of 250m for 4 hours a day, for eight days whilst exploring the sea floor in the Gulf of Ajaccio.Απο
http://www.ploprof.com/Site/PloProf.htmlThe Omega Ploprof achieved its pioneering level of water resistance through several patented design innovations. The first was the case, which was machined from a single block of stainless steel (patent CH 480680 from 1967). This construction ensured that there were only two points where water might get in – via the crystal, and the winding tube attached to the crown. To protect the crown, Omega designed a unique system (patent CH 503310 from 1968). What appears at first glance to be the crown is actually a knurled locking nut which compresses the crown and stem into the case; the crown itself is the square metal element that sits flush with the crown guards. A similar compressed gasket system protects the chemically reinforced mineral crystal (treated with both anti-reflective and scratch-resistant coatings) which is secured in a compressed gasket via a screwed down ring at a pressure of 120kg. The result is a crystal which can resist hydrostatic pressures of 60 atmospheres. The bidirectional rotating bezel is locked in place, and can only be unlocked by the distinctive orange pusher protruding from its housing on the right side of the case. As the bezel is designed to be used to measure the diver's remaining air supply, the Ploprof's bezel ensured that once set, the bezel could not be accidentally bumped and yield a life threatening false reading.
One of the most famous undersea missions associated with the Omega Ploprof was the 1970 “Operation Janus” - a diving expedition which took place on the sea-bed below the Gulf of Ajaccio. The Omega Ploprof spent eight days strapped to the wrists of all three of the divers from the French diving company COMEX which were hired by an oil research firm which was exploring the sea floor. However, it was the use of the Ploprof by none other than Commander Jacques-Yves Cousteau which gained the Omega Ploprof near cult status among collectors and enthusiasts of diving watches. Commander Cousteau worked closely with Omega during the Ploprof's 4 years of development, as he conducted a series of experiments designed to test man's capabilities and limitations when working at depths of 500m.
Απο-http://www.watchtalkforums.info/forums/omega-forum/45310.htm
