The History and Development of Rolex Sea-Dweller Deepsea

In the late 2000s, Rolex had been making waterproof mechanical watches for over 80 years, and had established themselves in the world of divers watches as the industry leader, with the most capable dive watch in the Rolex range being the Rolex Sea-Dweller ref 16600. In 2008 however, Rolex replaced its Sea-Dweller ref 16600 with a new addition to the Sea-Dweller range, the Rolex Sea-Dweller Deepsea ref 116660.

The Rolex Sea-Dweller Deepsea ref 116660, whilst it kept the recognisable Rolex diver style with is black ‘maxi’ dial and ceramic bezel, also measures in with a case 44mm wide and 17.7mm thick. It has a titanium/steel alloy case back, a 5.5mm thick domed sapphire crystal glass, and exhibited the revolutionary patented Rolex ‘Ringlock System’ that seals the glass to the case.
All this made the Rolex Sea-Dweller Deepsea ref 116660 the most water resistant mechanical watch in serial production. In order for Rolex to make this extraordinary claim, Rolex uses equipment developed by Comex to test that the watch case can withstand the enormous pressures needed to give it an official depth rating of 3,900 metres (12,800 ft). In order to be given this official depth rating, the Sea-Dweller Deepsea has to be tested to a depth of 125% of the official depth rating, in order to meet the demands of the safety reserve required by the ISO 6425 divers' watches standard. Meaning that the watch case is tested to a depth of 4,875 metres (15,994 ft).

The Rolex Sea-Dweller Deepsea takes its ‘Deepsea’ name from an experimental Rolex watch called the ‘Deep Sea Special’ from the 1960s. Since the early 1950s, Rolex had been working with a Swiss physicist and explorer by the name of Auguste Piccard who had designed the ‘Trieste’, a deep-diving research bathyscaphe submersible.
In 1960 Rolex teamed up with Piccards son Jacques Piccard and U.S. Navy Lieutenant Don Walsh as they descended in the Trieste to the deepest part of the worlds oceans, the Mariana Trench, in centre of the Pacific Ocean. This presented an ideal opportunity for Rolex to test its watches in real-life conditions, and so fixed to the outside of the bathyscaphe was an experimental prototype Rolex watch called the Deep Sea Special. The large watch was the latest prototype since the research and development into such a watch started in 1950. It had a bubble like domed glass, in a thick steel case to allow it to withstand the immense pressures it would be put under at the record breaking 10,916 metres (35,814 feet), a record that it held for almost 60 years.

In 2012, Rolex teamed up with another opportunity to send a Rolex watch to the depths of the Mariana Trench, this time with a variation on the Rolex Sea-Dweller Deepsea called the ‘Rolex Deepsea Challenge’. The Rolex Deepsea Challenge is a watch made specifically for James Cameron’s Deepsea Challenger Expedition, where the filmmaker and explorer piloted a custom-designed submersible to the deepest place on Earth, the first time anyone has done so since the first expedition in 1960. The custom watch made by Rolex for the expedition was designed using the same principles as the production model ref 116660 with its Ringlock System, but on a much more heavy duty scale making the watch much bigger at 51.4 mm wide and 28.5 mm high. The sapphire crystal was almost three times as thick as the standard model at 14.3 mm. The watch was strapped to a manipulator arm of a submersible piloted by filmmaker and explorer James Cameron, and was the ultimate test for its Ringlock system, with the system being able to withstand a pressure equivalent to a weight of 20 tonnes during tests.

In 2014 Rolex introduced a commemorative “James Cameron Dial '' option to the Rolex Sea-Dweller Deepsea ref 116660 with a blue dial that fades to black as a nod to the 2012 expedition done by him with the Rolex Deepsea Challenge.
Both the black dial and faded blue dial (sometimes referred to as the D-Blue) were carried over as Rolex updated the Sea-Dweller Deepsea range to the new ref 126660.
The Rolex Sea-Dweller Deepsea ref 126660 was launched in 2018, this new model came with the same diving capabilities as the previous model, but featured small updates to the design and movement in the watch. The new case on the ref 126660 has slightly wider lugs to accommodate a wider steel oyster bracelet, making the watch look a bit more in proportion than the ref 116660 it replaces.
The new 126660 also features the new Rolex in house calibre 3235 movement with its 70 hour power reserve.

The Rolex Sea-Dweller Deepsea range has a unique clasp design not seen on any other Rolex watches. The clasp has a double extension system, with a Fliplock extension link that sits under the clasp and works in a similar way to the Fliplock systems on other Rolex divers, but this one allowing a bracelet extension of 26 mm. But as well as the Fliplock extension, the clasp also has Glidelock functionality that allows the wearer to adjust the bracelet length up to 20 mm in 2-mm increments with a pop out ratchet function on the top of the clasp. These make the watch practical to use every day, with small adjustments for comfort, but also allowing it to be extended to fit over a wet suit or diving equipment.

Today the Rolex Sea-Dweller Deepsea ref 126660 runs alongside its sibling in the Rolex Professional range, the Rolex Sea-Dweller ref 126600. It is one of the most desirable Rolex models available, with extensive waiting times to get one from authorised dealers. The D-Blue James Cameron dial being the most popular variant, and it is thus proving to be a good investment for current owners as the price of watches on the used watch market climbs as supply from Rolex is further restricted.

Author: Watches by Timepiece