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Celebrating 50 years

The new Sea-Dweller (2017).

Left: The first Sea-Dweller (Ref 1665) was introduced in 1967. Right: One key feature of the Sea-Dweller remains despite all the changes made in its latest version - the helium escape valve.

THE Sea-Dweller is said to be the least popular of Rolex's sports watches. Yet the most talked about timepiece launched in March at the mega Baselworld watch fair in Switzerland was probably an updated model (Ref 126600) of the extreme dive watch. Retailers were already reporting a long customer queue for it, even before the new Sea-Dweller arrived in shops in July.

Rolex stopped production of the model in 2008 to develop the Deepsea, which can go as deep as 3,900 metres (12,800 feet) in water - over three times the depth which the Sea-Dweller can go. Still, collectors could not accept the Deepsea replacing the Sea-Dweller.

Perhaps that's why Rolex reintroduced the Sea-Dweller in 2014, with subtle improvements such as a slimmer case, ceramic bezel and adjustable glide-lock bracelet. Even so, why is another Sea-Dweller timepiece unveiled this year - so soon after the 2014 comeback?

There's a good reason for it. It's the dive watch's 50th birthday - and this time the changes made to it are more controversial, fanning further the buzz which surrounds the launch of the latest model.

The most obvious change is the case - it's bigger at 43mm, compared to 40mm in previous models. While there are supporters as well as critics, it's agreed that a larger case provides a clearer reading of the time, more comfort on the wrist and greater distinction from another Rolex dive watch - the Submariner. The change that created probably the most heated discussion is the magnifying cyclops on the date window. This was unexpected and somehow contradicted the idea of the original model.


The Sea-Dweller never had the cyclops, which was seen to have made the watch an exceptional Rolex timepiece; all other Rolex watches with a date have a cyclops.

Yet there's a technical reason for making the Sea-Dweller the exception: Until now, Rolex couldn't make a cyclops which could withstand the pressures at those depths which the watch could go.

Another visible change is the watch's name on the dial - "Sea-Dweller" is in red, a subtle reference to the model's origins.

The first Sea-Dweller (Ref 1665) was introduced in 1967 and those in production until 1977 had Sea-Dweller in red on the dial. Beneath it is printed Submariner 2000, also in red. This is an indication that these earlier models are water-resistant up to 2,000 feet deep, and that they are also similar to a Submariner model (Ref 5514) which Rolex made for Comex, a renowned professional diving company.

The lettering started to appear in white from 1977 and Submariner 2000 was not indicated on the dial anymore. The changes were made to better differentiate between the Submariner and Sea-Dweller timepieces.

A more substantial but unseen change in the new Sea-Dweller is its new Rolex movement (Calibre 3235), which is more precise and efficient, with a greater 70-hour power reserve.

The movement was introduced in the 2015 Day-Date model and used in the 2016 Datejust watch. The Sea-Dweller is the first Rolex sports timepiece to be powered by the new generation movement.

One key feature of the Sea-Dweller remains despite all the changes made in its latest version - the helium escape valve. It defines the Sea-Dweller and is arguably the reason for launching the watch in the beginning.


The helium escape valve, fitted into the watch's case, was built for extreme diving.

After World War II, diving became an increasingly popular sport. In 1954, Rolex introduced the world's first commercially produced dive watch, the Submariner (Ref 6200). This had a 100-metre water resistance (later 200m and 300m).

But by the 1960s, there was a greater demand for dive watches which could go deeper because of experiments on saturated diving - a technique which allows divers to reduce the risk of decompression sickness when they work at great depths for long periods of time. So, Rolex started working on a dive watch that could triple the Submariner's then 200m depth rating. A key problem was that the watch case could not withstand the pressure when it descended deeper in water. The helium escape valve was able to ease the pressure in the watch while maintaining its water-proofness at greater depths.

The helium escape valve was first used in the Submariner Ref 5514, made for Comex. Shortly after, it was introduced in the first Sea-Dweller. In 1978, Rolex unveiled a Sea-Dweller watch (Ref 16660) fitted with a sapphire crystal, a bigger helium release valve and a depth rating of 1,220m, double the rating of the earlier models.

Finally, in 1988, Ref 16660 was given a modern movement (Calibre 3135), solid end-links on the bracelet and a glossy dial.

Even with the new watch launched this year, the question of whether Rolex will continue with the Sea-Dweller lingers. Will the Deepsea make it redundant? There's already talk that the latest Sea-Dweller model is a one-off, issued only to mark the Sea-Dweller's 50th anniversary.

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