How Rolex conquered the deep
When the Hydra VIII mission by Comex (Compagnie Maritime d'Expertises) set the world open-sea diving record at a depth of 534 metres in 1988, the watch that accompanied the divers on their mission was a Rolex Oyster Perpetual Sea-Dweller chronometer. This model was standard equipment for the world leader in marine engineering.
It was the only watch the firm’s elite divers fully trusted on their saturation dives to great depths – when precise timing is of vital importance at every stage – and the watch they had used on thousands of successful underwater missions in extreme conditions. Thanks to its Rolex-patented helium valve, this legendary watch was instrumental in the conquest of the deep. It is being reintroduced in an updated version that benefits from Rolex’s latest technical innovations while remaining faithful to the iconic aesthetics of the original model.
The original helium escape valve, the key to the deep.
The Sea-Dweller 4000
Developed in 1967, waterproof to a depth of 610 metres (2,000 feet) initially and then to 1,220 metres (4,000 feet) in 1978, the Sea-Dweller is the watch for the pioneers of the deep. Those who were once known as aquanauts, explorers of the hydrosphere – the waters which cover some 70 per cent of the Earth’s surface. Like them, the Sea-Dweller had to adapt to the artificial breathing mixes devised for great pressure environments and composed of light gases such as helium or hydrogen. The watch has to face the same long decompression process as the diver undertakes in order to safely eliminate those gases without injury and avoid potentially fatal decompression sickness, or ‘the bends’, before he returns to the surface. With this in mind, in 1967 an important innovation developed and patented by Rolex was introduced on the Sea‑Dweller: the helium escape valve. This ingenious safety valve, set in the watch case, played an all-important role in the development of deep‑sea diving, a field in which Comex was the most renowned player. The company’s late founder and president, Henri-Germain Delauze, a pioneer of deep diving, said of his favourite watch: “A diver breathing hydrogen can’t live without his Rolex,” adding; “In diving, time is a crucial piece of information. Be it operations, changing gas mixes, timing decompression stops, entering and exiting the diving bell, it’s all a matter of seconds. Having a precise, robust, reliable watch was of vital importance.”
In diving, time is a crucial piece of information. Having a precise, robust, reliable watch was of vital importance.
Helium escape valve
In habitats at overpressure, which are filled with breathing mixes composed largely of helium, the watches behave in a similar manner to the divers’ bodies. The inner part of the watch case becomes saturated with helium as the pressure inside the watch case equalizes with that inside the chamber. Due to the extreme volatility of this light gas, which has the smallest molecules on Earth, the helium gradually penetrates the watch through the gaskets. During the decompression phase, helium is eliminated from human tissue at a faster rate than it can escape from a waterproof watch, with the result that pressure effectively builds up inside the watch case. Divers often observed during decompression that the watch crystal could pop out like a champagne cork from a bottle, due to this internal pressure. The watch must also be able to eliminate the excess helium inside the case.
Instead of attempting to make the watch impervious to helium, a practically impossible task, Rolex developed a unidirectional valve on the side of the watch case. It is activated automatically above a certain level of internal pressure to allow the gas to escape from the case, without affecting the waterproofness of the watch. Patented in 1967 by Rolex for its new professional divers’ model, the Oyster Perpetual Sea‑Dweller, the helium valve proved invaluable to the rise of deep-sea saturation diving. Comex swiftly adopted the Sea-Dweller as its official watch, as its divers continued to push ever further the limits for manned deep dives. The open-sea record of 534 metres set in 1988 was followed by another record in 1992 at an experimental depth of 701 metres in a hyperbaric chamber, with a 24-day decompression period – a record which still stands today.
The new Oyster Perpetual
In 2014, Rolex is bringing a legend of professional diving back to life with a brand new, updated Oyster Perpetual Sea-Dweller 4000. This 40‑mm‑diameter technical model, waterproof to a depth of 1,220 metres (4,000 feet), features all the latest Rolex standards of innovation: Cerachrom bezel insert in a ceramic virtually impervious to scratches and ultraviolet rays; Chromalight display with long-lasting luminescence; paramagnetic blue Parachrom hairspring; Oysterlock safety clasp; and the Rolex Glidelock extension system. Not forgetting, of course, the groundbreaking function for which the Sea-Dweller is renowned, the helium escape valve.