A legend among divers’ watches, the Oyster Perpetual Sea-Dweller was created to accompany the pioneers of deep-sea diving.
The Sea-Dweller, launched in 1967, is a technical divers’ watch that was designed for the pioneers of professional deep-sea diving. It is equipped with the helium escape valve, patented by Rolex the same year. This safety valve allows excess pressure built up inside the watch case to escape during a diver’s decompression phase in a hyperbaric chamber, without compromising the waterproofness of the watch. The first versions of the Sea-Dweller were guaranteed waterproof to a depth of 610 metres (2,000 feet); the Sea-Dweller 4000 was then guaranteed to a depth of 1,220 metres (4,000 feet) in 1978.
Updated in 2017 for its 50th anniversary, the Sea-Dweller features a larger 43 mm case and calibre 3235, as well as the Cyclops lens on the crystal to magnify the date for easier reading.
BEZEL WITH CERACHROM INSERT
The unidirectional rotatable bezel of the Sea-Dweller is fitted with a 60-minute graduated monobloc Cerachrom insert in black ceramic that allows divers to monitor their time underwater. The insert, patented by Rolex, is made of an extremely hard, virtually scratchproof ceramic whose colour is unaffected by ultraviolet rays. In addition, thanks to its chemical composition, the high-tech ceramic is inert and cannot corrode. The moulded, recessed graduations and numerals are coated with yellow gold or platinum using a PVD (Physical Vapour Deposition) process. The bezel’s knurled edge offers excellent grip, to comfortably set dive time even when wearing gloves.
LEGIBLE AND FUNCTIONAL
Great attention was paid to the legibility of this divers’ watch. On the dial, the Chromalight hour markers and hands are filled or coated with a luminescent material emitting a long-lasting blue glow – for up to two times longer than traditional phosphorescent materials. On the bezel, the triangular ‘zero’ marker of the graduation is visible in the dark thanks to an embedded capsule containing the same luminescent material.
THE SEA-DWELLER, A SUPERLATIVE CHRONOMETER CERTIFIED
Like all Rolex watches, the Sea-Dweller is covered by the Superlative Chronometer certification redefined by Rolex in 2015. This exclusive designation attests that every watch leaving the brand’s workshops has successfully undergone a series of tests conducted by Rolex in its own laboratories and according to its own criteria. These certification tests apply to the fully assembled watch, after casing the movement, guaranteeing superlative performance on the wrist in terms of precision, power reserve, waterproofness and self-winding. The Superlative Chronometer status is symbolized by the green seal that comes with every Rolex watch and is coupled with an international five-year guarantee.
The precision of every movement – officially certified as a chronometer by the Swiss Official Chronometer Testing Institute (COSC) – is tested a second time by Rolex after being cased, to ensure that it meets criteria that are far stricter than those of the official certification. The precision of a Rolex Superlative Chronometer is of the order of −2/+2 seconds per day – the rate deviation tolerated by the brand for a finished watch is significantly smaller than that accepted by COSC for official certification of the movement alone.
The Superlative Chronometer certification testing is carried out after casing using state-of-the-art equipment specially developed by Rolex and according to an exclusive methodology that simulates the conditions in which a watch is actually worn and more closely represents real-life experience. The entirely automated series of tests also checks the waterproofness, the self-winding capacity and the power reserve of 100 per cent of Rolex watches. These tests systematically complement the qualification testing during development and production, in order to ensure the watches’ reliability, robustness, and resistance to magnetic fields and shocks.
THE OYSTER CASE, SYMBOL OF WATERPROOFNESS
The Sea-Dweller’s Oyster case, 43 mm in diameter and guaranteed waterproof to a depth of 1,220 metres (4,000 feet), is a paragon of robustness and reliability. The middle case is crafted from a solid block of Oystersteel, a particularly corrosion-resistant alloy. The case back, edged with fine fluting, is hermetically screwed down with a special tool that allows only certified Rolex watchmakers to access the movement. The Triplock winding crown, fitted with a triple waterproofness system and protected by an integral crown guard, screws down securely against the case, providing watertight security. The crystal, with a Cyclops lens at 3 o’clock to enhance the reading of the date, is made of virtually scratchproof sapphire. The waterproof Oyster case provides optimum protection for the Sea-Dweller’s movement.
PERPETUAL CALIBRE 3235
The Sea-Dweller is equipped with calibre 3235, a self-winding mechanical movement entirely developed and manufactured by Rolex. A consummate demonstration of technology, this movement carries a number of patents. It offers outstanding performance in terms of precision, power reserve, resistance to shocks and magnetic fields, convenience and reliability.
The oscillator of calibre 3235 has a large balance wheel with variable inertia regulated extremely precisely via gold Microstella nuts. It is held firmly in place by a height-adjustable traversing bridge enabling very stable positioning to increase shock resistance. The oscillator is also fitted on high-performance Paraflex shock absorbers, designed and patented by Rolex.
Calibre 3235 has an optimized version of the blue Parachrom hairspring, manufactured by Rolex in a paramagnetic alloy. Insensitive to magnetic fields, the Parachrom hairspring offers great stability in the face of temperature variations and remains up to 10 times more precise than a traditional hairspring in case of shocks. It is equipped with a Rolex overcoil, ensuring its regularity in any position.
This calibre incorporates the Chronergy escapement, made of nickel-phosphorus and patented by Rolex, which combines high energy efficiency with great dependability and is also insensitive to magnetic fields.
Calibre 3235 is fitted with a self-winding module featuring a Perpetual rotor, which ensures continuous winding of the mainspring by harnessing the movements of the wrist to provide constant energy. Thanks to its barrel architecture and the escapement’s superior efficiency, the power reserve of this movement extends to approximately 70 hours.
The Sea-Dweller’s movement will be seen only by certified Rolex watchmakers, yet it is beautifully finished and decorated in keeping with the brand’s uncompromising quality standards.
BRACELET AND CLASP: SECURE AND COMFORTABLE
The Sea-Dweller is fitted on a three-piece link Oyster bracelet. Equipped with a Rolex-designed and -patented Oysterlock safety clasp that prevents accidental opening, this bracelet also features the Rolex Glidelock extension system, designed and patented by the brand. This inventive toothed mechanism, located under the clasp cover, enables fine adjustment of the bracelet length, without tools. The Rolex Glidelock on the Oyster bracelet has 10 notches of approximately 2 mm each, allowing the bracelet length to be adjusted easily up to some 20 mm. The watch can therefore be worn over a diving suit up to 3 mm thick.
The Oyster bracelet on the Oystersteel version is additionally equipped with the Fliplock extension link, whose fold-out links enable the bracelet to be extended by approximately 26 mm, again without the use of tools. Together, the two extension systems allow the watch to be worn over a diving suit up to 7 mm thick.
A concealed attachment system ensures seamless visual continuity between the bracelet and case.