The watch divers rely on
The divers of the French Compagnie Maritime d’Expertises were true professionals. Like many of their colleagues, COMEX’s men relied on the time-honored Rolex Submariner. Their timekeeping situation changed when closed bells were invented so divers could acclimate above the surface to pressure conditions they’ll afterwards encounter at their working depth. A special helium-enriched breathing gas was essential for longer sojourns at deeper depths, but this gas caused massive problems for conventional watches. While divers tarried in a pressurized chamber, helium molecules penetrated through the gaskets and Plexiglas crystals into their watches. When the pressure later decreased, helium escaped so slowly that excess pressure in the case could blow off the crystal. Patented in 1967, an ingenious valve on the left- hand flank solved the problem. The valve automatically comes into play when the interior pressure exceeds 2.5 kg/cm2. That same year, Rolex installed the valve in the new Sea-Dweller, which COMEX’s divers chose as their official wristwatch. Rolex fetes this model’s fiftieth birthday in 2017 with the 43 mm Reference 126600, which is water-resistant to 122 bar. A helium valve is installed in the left-hand flank of the steel case that features a scratch-resistant rotating Cerachrom bezel. Caliber 3235 is the horological delicacy inside the case: protected by 14 patents, several years were required to develop this innovative self-winding Rolex manufacture movement with bidirectionally winding rotor. Its Chronergy escapement with narrow pallet jewels (a mere 1.25 mm wide) boosts efficiency by 15 percent, while the pallet lever and escape wheel are made from paramagnetic nickel materials manufactured using the precise photo- lithographic LIGA method. A longer mainspring contributes to this caliber’s ability to keep running at a steady pace of 4 Hz for 70 consecutive hours. This watch deviates from the time shown on an atomic clock by no more than -2 to +2 seconds per day and comes with a global five-year guarantee.