The Rolex Oyster Perpetual Date Sea-Dweller is a line of diver’s watches manufactured by Rolex, with an underwater diving depth rating of 610 metres (2,000 ft) for the vintage models and up to 3,900 metres (12,800 ft) for the most recent Sea-Dweller model.
During the 1960s, commercial work in the oceans and seas created professional diving organisations that needed tool watches designed for conducting safe diving operations at greater depths – known as saturation diving. This led to the development of the first ‘ultra water resistant’ watches.
The Sea-Dweller’s integrated helium escape valve
The Rolex Oyster Perpetual Sea-Dweller Submariner 2000 (2000 ft = 610 m) that became available in 1967 was developed from the Submariner for the Comex S.A. industrial deep-sea diving company by increasing crystal thickness and was produced in several variations. Most Sea-Dweller watches incorporate a helium escape valve for saturation diving. Early Sea-Dwellers did however not always have the helium escape valve. Another feature setting it apart is the absence of a date magnification bubble, the cyclop, present on most Rolexes. Since 1977 the Rolex Sea-Dweller diving watch range have served as standard issue diving watches for Comex divers.
The Sea-Dweller Submariner 2000 watches have 2 red text lines on the watch dial which led to an unofficial “Double Red” designation under watch collectors for these watches.
The Sea-Dweller Submariner 2000 (2000 ft = 610 m) models were succeeded by the Rolex Oyster Perpetual Sea-Dweller 4000 (4000 ft = 1220 m) model with an increased depth rating. The current Comex Sea-Dweller 4000 Rolex reference number is 16600 and this watch has been issued to Comex divers since 1992.
At the BaselWorld watch and jewellery show 2008, Rolex introduced an updated Sea-Dweller model, named the Rolex Oyster Perpetual Date Sea-Dweller DEEPSEA. Its reference number is 116660. With an official depth rating of 3,900 metres (12,800 ft), the Sea-Dweller DEEPSEA represented in its launch year the most water resistant mechanical watch in serial production. For obtaining this official depth rating the Sea-Dweller DEEPSEA water resistance is tested to a depth of 4,875 m (16,000 ft) to offer the 25% safety reserve required by the ISO 6425 divers’ watches standard. To test the water resistance of the Sea-Dweller DEEPSEA, Rolex uses testing equipment developed for them by Comex.
Normal surface air filled watch cases and crystals designed for extreme depths must be dimensionally large to cope with the encountered water pressure. To obtain its water resistance the Rolex Sea-Dweller DEEPSEA watch case has a diameter of 43.0 mm, thickness of 17.7 mm (domed crystal thickness 5.5 mm) and the case and bracelet weigh 220 g.
The design and actual availability of diver’s watches certified for more than 1,000 meters (3,281 ft) is not solely explicable by practical diving needs.
The diving depth record for actual off shore diving was achieved in 1988 by a team of professional divers of the Comex S.A. industrial deep-sea diving company performing pipe line connection exercises at a depth of 534 meters (1752 ft) of sea water (MSW) in the Mediterranean Sea. The diver’s watches used were Rolex Sea-Dwellers.
In 1992 Comex diver Theo Mavrostomos achieved a record of 701 MSW (2300 ft) in an on shore hyperbaric chamber. He took 43 days to complete the dive. The watch used during this scientific record dive, where a hydrogen-helium-oxygen (hydreliox) gas mixture was used as breathing gas, was a Rolex Sea-Dweller 4000. Rolex used this achievement in advertising campaigns.
The complexity, medical problems and accompanying high costs of professional saturation diving to extreme depths and the development of deep water atmospheric diving suits and remotely operated underwater vehicles in offshore oilfield drilling and production effectively nixed the need for ever deeper non-atmospheric manned intervention in the ocean.