The oceans cover three-quarters of our planet, yet we know less about them today than about the surface of the Moon. As technological advances allow for ever more in-depth exploration of the Earth’s seas, Rolex continues to be at the forefront of technology as the maker of reference diving watches.


French novelist Jules Verne caught the imagination of his time in 1870 with his book Twenty Thousand Leagues Under the Sea, and underwater science-fiction novel featuring fantasy seacrafts that allowed humans to venture into the deepest reaches of the ocean. By the turn of the 20th century, submarines had become a reality, yet it wasn’t until the late 1940s and the advent of scuba (Self Contained Breathing Apparatus) diving that the old human dream of wandering freely under water like fish was achieved. The only “string” attached to the activity of scuba divers was the limited supply of air available to their “aqualungs”, requiring careful management of the time spent under water. The divers also had to make decompression stops and carefully pace their ascent to the surface in order to safely eliminate the absorbed inert gases from their body and avoid decompression sickness. Here again good timing was essential. So the advent of scuba diving created a new and literally vital need for reliable underwater timing instruments. As the pioneer of the waterproof watch, Rolex was up to that challenge.

rolex submariner 116610 lv green bezel rolex submariner 116610 lv 50th anniversary vintage db rolex seadweller 16600


It all started in 1926, when Rolex unveiled the Oyster, the first waterproof wristwatch in the world thanks to its patented screw-down case back, bezel and winding crown. By the time scuba diving emerged some 20 years later, the Rolex Oyster had been continuously perfected and was ready to take a deeper plunge. At the beginning of the 1950s, the case’s waterproofness was decisively reinforced with the introduction of the Twinlock winding crown, the next generation of the Rolex patented screw-down crown. Featuring two separate synthetic seals for double waterproofness, it even kept the watch dry when the crown was not screwed down onto the middle case. In 1953, Rolex launched the Submariner, the first wristwatch guaranteed waterproof to a depth of 100 metres. It was designed specifically for underwater exploration and diving, with a strong stainless steel bracelet and an extra robust and waterproof Oyster case. Its black dial with white hands and indices, coated with luminescent material, provided optimal legibility even in the twilight of the depths. A graduate rotatable bezel functioned as a simplified – and waterproof – chronograph, allowing divers to time their oxygen supply and their safety stops. Later the same year, the pressure and water resistance of the Submariner was increased to 200 metres. A highly accurate, dependable and waterproof “tool” adopted by professional diver and soon became the gold standard of diving watches. Indeed, the Submariner proved so rugged that it became the watch of choice for sports and activities far beyond diving. Its rugged elegance even made it a good fit for a drink by the pool or a black-tie gala.


Rolex never satisfied itself with good engineering and design to ensure the high performance of its watches. Its claims were tried and proven in the field by putting the watches through real-life tests. “The world is our laboratory,” Rolex founder Hans Wilsdorf used to say. In putting its new diving watch to the test, Rolex worked closely with oceanographic explorers and professional divers to validate its technical choices and constantly improve the performance and functionality of its underwater timepieces.
During the development of the Submariner in the early 1950s, Rolex collaborated with Swiss scientist Auguste Piccard, who invented the bathyscaphe Trieste, a unique deep-diving submersible, and with his son Jacques, an oceanographer (see article p.10). By 1950 Rolex had developed an experimental Oyster, the Deep Sea Special, designed to resist the extreme pressure of the abyss. The brand used the Trieste’s deep-dive explorations to test its prototype in real-life conditions.
In 1953, a Rolex Deep Sea Special was attached to the outside - and returned unharmed and perfectly working from a dive to a depth of more than 3,000 metres. On 23 January 1960, a new version of the Deep Sea Special took part in an attempt by the Trieste to reach the deepest point of the world’s ocean bed, in the Mariana Trench in the Pacific Ocean. Strapped once again to the bathyscaphe’s hull, the Rolex prototype went down to a record depth of 10,916 metres. When the Trieste surfaced after nine hours in the deepest reaches of the ocean, the watch was found to have kept perfect time, indicating it had worked during the entire dive and resisted a pressure of one tonner per square centimetre, in a telegram, Jacques Piccard congratulated Rolex for its watch which was, her said, as accurate at 11,000 metres below as at the surface, this exploit confirmed Rolex’s unparalleled expertise in pressure resistance and waterproofness for diving watches. To this day, the depth record set by the Rolex Deep Sea Special in 1960 remains unmatched.

The Oyster case is crafted from a single piece of high-grade, highly corrosion-resistant 904L stainless steel, and features an integral crown guard.

The Triplock winding crown features three waterproofness seals and screws down onto the middle case like the hatch of a submarine.
The Cerachrom disc bezel is made of extremely hard ceramic. It is virtually scratch- and corrosion-proof, and its colour is unaffected by ultraviolet rays.

The graduated rotatable bezel works like a simplified chronometer and allows divers to safely time their oxygen supply and safety stops. Its luminescent capsule keeps it functional even in dark waters or at night.


But diving watches are meant for humans, not bathyscaphes. In parallel with waterproofness testing, Rolex worked closely with professional divers to continuously improve the performance and functionality of its diving watch. The feedback from these field users led the evolution of the Submariner during the entire decade of the 1950s.
The hour and minute hands were better differentiated in order to avoid any possible confusion with the introduction of the landmark luminescent sign on the hour hand. The graduation on the bezel was marked down to the minute for the first 15 minutes to allow more accurate timing of the safety stops. The edge of the bezel was notched deeper and the winding crown enlarged to offer a better grip. And to protect this crown against knocks and shocks, Rolex invented the crown guard – metal shoulders on both sides of the crown which are an integral part of the case.
They were introduced on the Submariner in 1959, together with a larger 40mm case (up from a previous 36mm). By that time, most of the defining features of the Submariner’s iconic design were in place, making it the archetype of the diving watch – which it remains today. Subsequent developments comprised the introduction in 1969 of a Submariner version which included the date and a magnifying Cyclops lens as well as a gold version, and in 1979 the waterproofness was increased to 300 metres.
By then, this performance was far exceeded y Rolex’s own Sea-Dweller, a new model created in 1967 to meet the new and most demanding needs of specialised deep-diving professionals using new saturation techniques. And Rolex was up to the challenge again: it stayed at the forefront.


If the 1950s were a time of discovery and exploration of the underwater world, in the 1960s the focus turned to pushing the boundaries in terms of how deep humans could go and how long they could live and work in the sea as well as exploiting its riches, for off-shore oil in particular. The development of saturation diving and new breathing mixes by the end of the 1950s provided the technical capabilities for ever deeper ventures and extended stays in the sea while avoiding the deadly effects of decompression sickness or “the bends”. Experimental underwater habitat programmes were launched in the 1960s by French oceanographer Jacques-Yes Cousteau (Conshelf) to allow humans to “dwell” and work in the oceans for several weeks.
Around the same time, offshore oil drilling and other marine engineering needs led to the creation of commercial diving companies specialized in deep-dive operations using saturation techniques. One of the most renowned and pioneering firms was the French company COMEX (Compagnie Maritime d’Expertises), founded in 1961 and run ever since by Henri Germain Delauze (see interview p.63). COMEX divers were equipped with Submariner watches. Their experience and feedback were instrumental in the development of the next generation “ultra-waterproof watch”, aptly named the Sea-Dweller.
COMEX divers, constantly trying to reach greater depths, were getting closer to the 200-metre waterproofness limit of the Submariner. Around the mid-1960s, COMEX collaborated with Rolex to develop watches that could go deeper. COMEX founder Henri Germain Delauze was the first man to reach 335 metres deep in 1968. To deliver on this request Rolex could “beef up” the Oyster case and its components, drawing on the experience grained with the Deep Sea Special. But there was another challenge.

The original. First diving watch guaranteed waterproof to 100 metres.

Large winding crown with protective shoulders, bezel with 15 minutes graduation and deeper notches, distinctive hour hand and waterproof to 200 metres.
Same look, increased performance: waterproof to 610 metres and with a helium valve.


COMEX saturation divers were experiencing a rather troublesome phenomenon that affected their watches during the decompression phase after deep dives. In order to bring them slowly back to the normal atmospheric pressure, saturation divers had to spend lengthy stages in decompression chambers breathing Heliox, a gas mixture which is around 95% helium. Helium molecules are so tiny they can slowly penetrate the watch case through the seals, so the pressure inside the watch becomes the same as inside the habitat. On decompressing the chamber however, the gas is unable to escape from the waterproof case quickly enough. The resulting pressure difference inside and outside the watch often resulted in the crystal of the watch popping, off, rather like a champagne cork.
To address this issue, Rolex invented and patented the gas escape valve, a one-way valve which safely allows the helium trapped in the watch to be released at a given pressure while preserving the tight waterproofness of the Oyster case.
Building on these innovations, Rolex launched a new “supercharged” professional diving watch in 1967: the Sea-Dweller. It was guaranteed waterproof to a depth of 600 metres, offering a comfortable safety margin over the deepest dives of the time, its appearance and functionalities were very similar to the Submariner, except that, apart from the helium valve, the Sea-Dweller was a little thicker and had no Cyclops on the date.
Rolex also graced it with another innovation: a “Fliplock” extension link of the bracelet allowing the watch to be worn on top of the thick diving suit used by technical divers to insulate them from the cold at such depths.
COMEX was so pleased with Sea-Dweller that, as of the early 1970s, it ruled that only Rolex diving watches were to be used by their divers. The Sea-Dweller would soon accompany them to new record depths. In 1977, COMEX divers reached 501 metres below the surface, once again challenging the original depth-rating of the Sea-Dweller at 610 metres. One year later, Rolex raised the bar further and set new standards for professional diving watches. This time, humans could not keep up.


In 1978, Rolex engineers achieved a twofold increase in the guaranteed waterproofness of the Sea-Dweller, from 610 metres to 1,220 metres. By comparison, modern military nuclear submarines have a crush depth (the submerged depth at which their hull will collapse due to pressure) of about 750 metres. As hydrogen used in the deep-diving breathing mixes becomes toxic below 700 metres, this is considered to be the physiological limit for humans in the current state of technology. This ultimate threshold was reached by a COMEX diver in a compression chamber in 1992, setting a world record at 701 metres which is still unmatched today. The Sea-Dweller the diver was wearing worked just fine under these extreme conditions, with another 520 metres of leeway before starting to really feel the pressure.
On these new Sea-Dwellers, Rolex upgraded the crystal piece. Scratchproof sapphire crystal was introduced, tightly assembled on the middle case with a polymer seal. The screw-down case back and the Trip-lock winding crown, introduced in 1970 with a third waterproofness seal, were so “over-engineered” that they did not require any improvement. The Triplock crown actually proved so efficient that it was used unaltered some 40 years after its invention when Rolex launched its latest abyssal watch in 2008, the Rolex Deepsea.
This time the performance increase compared to the previous generation was more than threefold, reaching the extreme depth of 3,900 metres below the sea. This next-generation professional diving watch provides a high level of security to the most demanding divers, who value the superior robustness and reliability of a mechanical watch.
The entire architecture of the Rolex Deespsea case has been re-engineered to ensure this phenomenal pressure resistance without compromising on the size and thickness of the watch. The result is the patented Ringlock System architecture, featuring a high-performance nitrogen-alloyed stainless steel. It provides the backbone supporting a dense 5mm done-shaped sapphire crystal and a grade-5 titanium alloy case back (see illustration above). It can withstand four tonnes of force, which is equivalent to the pressure at 3,900 metres.
To guarantee the stated water and pressure resistance, a new generation of testing equipment also had to be developed in order to test 100% of the watches during production. Rolex worked closely with COMEX experts to build a custom-made hyperbaric tank (see p.63), which simulates the pressure at 4,875 metres below sea level – some 25% greater than the depth indicated on the watch dial.

Allows the watch to “decompress” with the diver after deep saturation dives by safely releasing the helium trapped in the watch.

This integrated extension system allows for adjustment of the bracelet in 2mm increments up to about 20mm in order to wear the watch over a diving suit.


As the flagship diving watch, the Rolex Deepsea introduced innovations which later benefitted the Submariner. The graduated bezel aluminium disc of the rotatable bezel has been replaced with a Cerachrom disc made of extremely hard ceramic, this exclusive and highly durable component is virtually impervious to scratches and corrosion, and its colour will not fade as it is unaffected by ultraviolet rays of the sun. It also offers excellent legibility of the engraved graduations, which are deposited with a thin layer of gold or platinum via a patented process. T legibility of the dial has been greatly enhanced by the new Chromalight display, using an advance luminescent material on the hands, indices and markings, which emits a blue glow lasting up to twice as long in the dark. The movement of the Rolex Deepsea integrates the Rolex patented blue Parachrom hairspring, which remains up to 10 times more accurate in case of shocks and is perfectly insensitive to magnetic fields. The bracelet has also received a lot of attention. Like the case, it is crafted in highly corrosion-resistant 904L stainless steel - a standard pioneered by Rolex on all its diving watches since 1985. The patented Rolex Glidelock clasp lets divers expand the band by up to about 20mm in 2mm increments, while the Fliplock extension links allow it to be further lengthened, for a total of about 45mm. This remarkable extension provides leeway for a secure and comfortable fit even over the thickest of diving suits. These innovative features were passed on to the stainless steel Submariner Date in 2010, further enhancing the functionality, robustness, precision and appeal of this iconic diving watch. A spectacular green version completed this overhaul, with a green Cerachrom bezel and a unique green gold dial.


In the deepest reaches of the world’s waters, at depths at which no light penetrates, the mysterious universe of the oceans still has many secrets to reveal. As scientists, explorers and conservationists consolidate their efforts on the ocean’s resources and how to best preserve them, Rolex continues to innovate right alongside them, leading the way into the most fascinating and uncharted waters on our planet with cutting-edge performance and legendary style.

(C) COPYRIGHT - Rolex Exploration Perpetual Spirit

By Grégoire Baillod