Before becoming one of the world’s foremost producer of luxury timepieces, Rolex was mostly known as a manufacturer of professional timepieces. They released a number of models targeted to an extremely restricted and specific audience (at least at the beginning): from the Submariner (developed for relatively common scuba divers), to the Milgauss (made for personnel working in the presence of strong magnetic fields), to the Explorer (made for, indeed, explorers conquering at the time the last corners of the world where no human had yet set foot) to the present, and possibly most “professional” and specific of them all, Sea-Dweller. While widely used by scuba divers as an improved version of the Submariner, the Sea-Dweller was in fact developed - in conjunction with COMEX - for an extremely specific purpose: to be worn in hyperbaric chambers or “underwater habitats”, experimental underwater facilities where scientists would live for days or even weeks, conducting researches on underwater environment. Due to the high pressure making normal air toxic, a special mixture of gasses had to be used in pressurized atmospheres, helium among those. Helium atoms are extremely tiny, so much that they would penetrate into the watch through the gasket, and when depressurizing the expansion of the gas inside the watch would pop the crystal. The Sea-Dweller solved this issue with the addition of a valve in the band which allows the trapped gas to escape.
It is obvious how such a technical piece was truly necessary only to a handful of individuals on the planet, highlighting the ethos of Rolex at the time.
While in the end Rolex released the Sea-Dweller to the general public, the present example, in the rare and extremely appealing “Double Red” configuration nonetheless, is in fact one of the few specimens that have been used to the full extent of their capabilities. As proudly engraved (by Rolex) on its back, it originally belonged to Philippe Jeantot, one of the 6 members of the Janus IV - Phase B (Phase A took place the previous year, reaching a max simulated depth of 480 meters) expedition. The Janus project, made by Comex in conjunction with Rolex, consisted in a series of dives made between 1968 and 1977 with increasing depth starting at 150 meters (Janus I). Janus IV will eventually reach a depth of 501 meters below sea level, marking a world record for scuba diving that lasts to this day and will most probably never be beaten. Not only the improved depth resistance was necessary for such a feat, but also the Helium Escape Valve: in order to reach such an enormous depth, the divers had to live for several days before the attempt in a hyperbaric chamber which was slowly pressurized with a mixture of helium, oxygen and nitrogen (Trimix Helium) to a pressure equivalent to 430 meters below sea level. Furthermore, during the descent the pressure was further increased to the equivalent of 490 meters (and from that point the dive to 501 meters took place). Without an escape valve, there is no way the watch would have come out of decompression intact.
A true piece of history, a tool watch exploited out of necessity in all of its capabilities and a witness to a nearly superhuman feat which is likely to rest unchallenged for the foreseeable future, it is without a doubt that they present watch is one of the most important Sea-Dweller watches - nay! All professional watches - to ever appear on the market, and the “human” counterpart to the Deepsea Special (lot 248): where the latter reached the lowest depth achieved by a manned vehicle, this watch was present when humankind marked the lowest depth for an “unshielded” dive.
