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COMEX Watches: Rolex vs Omega – the Ultimate Dive Watch

COMEX Watches: Rolex vs Omega – the Ultimate Dive Watch

COMEX watches

COMEX watches from Rolex and Omega revolutionised the field of saturation dive watches but how did they actually rise to success? In today’s article, let’s take a look at the Omega Seamasters, Rolex Submariners and Rolex Sea-Dwellers which were used by this iconic French diving firm.

Amongst watch lovers and enthusiasts, the acronym ‘COMEX’ has developed a unique attraction. Being the name of France’s Compagnie Maritime d’Expertises, this diving firm became the leader in underwater research from the 1970s onwards after the likes of Jacques-Yves Cousteau and the U.S. Navy went in different directions in the late 1960s.

Omega Seamaster Ploprof Sothebys
Omega Seamaster 600 ‘Ploprof’ ref. 166.077 | Photo: Sotheby’s

Most importantly, this company had a very close involvement with watches from Rolex and Omega. It was through COMEX and its endeavours that the Rolex Sea-Dweller became the watch it is today and the Omega Seamaster PloProf became an icon of the deep. However, the truth behind how this happened is often recounted in dribs and drabs and, as with many things, the truth is rather more complicated than it at first seems. Today, and in line with the historical core of WATCH CHRONICLER, I would like to take you on a subaquatic journey through just how COMEX created legends of these dive watches.

COMEX: Masters of the Deep

COMEX advert
Photo: CACx 2015, Dominique Breheret & Annie Harriz

To give you a bit of backstory, COMEX was formed in 1961 and, from the late 60s started to lead the field of technical and commercial diving. Specifically, it was COMEX’s work which pushed the limits of what an extreme diver could physically withstand. This was achieved with an array of hyperbaric equipment and research ships. In fact, COMEX is even known for developing the SAGA submarine which was to be the first commercial nuclear submariner with saturation diving facilities and was co-developed for France and Canada. The SAGA was based on the Argyronète, a 1966 submarine designed by Jacques Cousteau to accommodate divers as a ‘subaquatic house’. This project’s hull was bought by COMEX in the early 1980s and work on SAGA began. This ultimately fell through, but I think it illustrates just how serious COMEX were.

SAGA submarine
Photo: Les Amis du SAGA, Copyright 2002

The COMEX Divers & Their Watches

COMEX watches
Photo: CACx 2015, Dominique Breheret & Annie Harriz

When one thinks of COMEX, though, it is usually associated with saturation diving. Where these diving missions were concerned, the four most well known projects were PHYSALIE, JANUS, SAGITTAIRE, & HYDRA.

  • PHYSALIE (1968 – 1972) comprised experiments to understand how the human body reacted to pressure. This project revealed the effects of high-pressure nervous syndrome.
  • JANUS (1968-1977) was a project to evaluate the practical uses for commercial divers between 150 and 501 metres.
  • SAGITTAIRE (1971 – 1974), following the lines of PHYSALIE, took divers to depths between 300 and 610 metres to see physical and mental changes.
  • HYDRA (1968 – 1992) tested the use of experimental gases to reach absolute depth records between 70 and, with 1992’s HYDRA X, 701 metres.

So, where do watches come into this? Well, the first thing to know about the Rolex Submariners, Sea Dwellers and Omega Seamasters involved with COMEX is that their history is often misconstrued based on very sensible assumptions. A key assumption is that these brands only offered their watches to COMEX after they had started production. In truth, many watches used were prototypes courtesy of the testing opportunities inherent to a partnership.

Omega Seamaster 300 Jacques Cousteau ST165.024
Omega Seamaster 300 ref. ST165.024-63 worn by the Cousteau team during Conshelf II in 1963 | Photo: Christie’s

The story begins with Omega, a brand involved very closely with deep-sea exploration since Jacques Cousteau’s famous Conshelf missions to test the idea of a long-term undersea habitat for divers. During the Conshelf III mission in 1965 at a depth of 102.4 metres, the Omega Seamaster 300 watches worn started to exhibit a serious flaw: they blew-off their crystals as they ascended due to a build-up of helium inside the case under pressure. This incident, paired with similar ones elsewhere, was a key moment for Omega which started to work with up-and-coming COMEX in 1968.

Jacques Cousteau Conshelf II
Jacques Cousteau and his team during Conshelf II in 1963 | Photo: Robert B. Goodman – National Geographic / Getty Images

Omega Seamaster PloProf

At this point, Omega was highly ambitious to use their technical might to create the ultimate dive watch. Even so, the aforementioned Seamaster 300 was hardly a substandard product. Importantly, it used a crystal with an outer lip to be secured in place although, given its failures, this clearly wasn’t sufficient. After conducting tests, Omega returned to COMEX with two prototype watches: the Ploprof 1 and Ploprof 0.

Omega Seamaster 166.077
Omega Seamaster 600 ‘Ploprof’ ref. 166.077 | Photo: Omega SA

Built from Uranus steel — the corrosion-resistant steel used for COMEX’s diving bells and what we now call 904L steel — these watches were a direct product of the diving firm’s engineering. Most importantly, these watches needed to fend off the ingress of helium — something they achieved by simply being entirely airtight: 100 times more airtight than even NASA’s Apollo crew capsule. This was managed through large, monobloc cases and a screwed crystal.

Omega Seamaster Ploprof 0 COMEX watches
Omega Seamaster ‘Ploprof 0’ used for Hydra I in 1968. Note the experimental hands, decompression bezel and unique second hand | Photo:

The idea with ‘Ploprof 0’ and ‘Ploprof 1’ prototypes was to get the divers’ perspective on the functionality of these watches and, interestingly, the favourite was the ‘Ploprof 0’. This featured a Flightmaster-style case and a simple rotating bezel as was used in 1968’s Hydra I experiment. Curiously, this example used the earlier cal. 552 of the Seamaster 300. This would ultimately become the later Seamaster 1000 whilst the ‘Ploprof 1’, the Seamaster 600, would be more of a favourite with Omega thanks to its push-button system for the bezel.

Omega Seamaster 600 PloProf
Omega Seamaster 600 ‘Ploprof’ ref. 166.077 | Photo: Omega SA

Today, we have the successor of the Seamaster 600 in the form of the modern 1200m PloProf although this doesn’t use the innovative design of the original. The original Seamaster 1000 and Seamaster 600 models used a crystal which was supported by a ring around the movement. As the pressure increased, it compressed the ring until, without breaking the seal, the hands were stopped by the crystal. This occurred at 1,370m for the Seamaster 600 but, to the best of my knowledge, nobody has put their Seamaster 1000 forward for a crush test, so we don’t know if it would fare any better.

The Underappreciated Seamaster 1000

Omega Seamaster 1000 Le Grand
Omega Seamaster 1000 ‘Le Grand’ ref. 166.093 | Photo: Omega SA

From what we know, it seems that COMEX’s divers found the Seamaster 600 variant a cumbersome and largely over-engineered option given the already limited use for a bezel during saturation diving. It’s worth also noting that the ‘Ploprof 0’ or Seamaster 1000 used by COMEX was in prototype form and often appeared with experimental hands and bezels. Despite being regarded as a diver’s favourite (even accommodating different wrist sizes with four lug holes), it is possible that the Seamaster 1000 would never have reached production without the help of some very illustrious friends.

Monaco Oceanographic Museum
The Monaco Oceanographic Museum | Photo: Stanimir Stoyanov / CC BY-SA (

In 1957, Jacques Cousteau began his tenure as the director of the Monaco Oceanographic Research Institute and Museum. In order to reward and celebrate friends of this institution, Prince Rainier III of Monaco is believed to have commissioned 50 dive watches from Omega other than the conventional Seamaster 600 ‘PloProf’. The result was the Seamaster 1000 ‘Le Grand’ of which the first was given to Cousteau. Subsequent demand drove the production of another 100 examples for the public market.

From 1968 all the way through to the Sagittarius 1 mission in late 1971, COMEX used Omega’s watches before, at last, moving to Rolex – the brand most often associated with this pioneering firm.

Rolex and COMEX

Rolex Submariner 5512 Sothebys
Rolex Submariner ref. 5512 | Photo: Sotheby’s

Before talking about that development, we do have to address which watch Rolex was proposing to use. You see, many people assume that the ref. 5513 and ref. 5514 200-metre Rolex Submariners with helium escape valves were the first attempt from Rolex to produce a saturation dive watch. However, the timeline suggests that these were a later addition in the 1970s. In the 1960s, it was the ref. 5512 and ref. 5513 Submariners (the 5512 being the chronometer version of the 5513) which were used by Rolex for missions such as the US Navy’s SEALAB which began to get seriously close to their 200-metre depth limit. As such, when Rolex began work on the Sea-Dweller in 1967, they were merely trying to make a deeper-diving watch as explained by the research of Jose Pereztroika on Perezcope.


In response to a desire for a deeper-diving watch, Rolex began work on the Sea-Dweller. During SEALAB 3, however, the prototype Single-Red 500m Sea-Dwellers worn began to explode on decompression and, soon after, Rolex fitted the iconic valve to relieve internal pressure. The story of how Rolex fitted the gas escape valve is varied, it now seems fairly conclusive that it was a single-red model worn by Dr Ralph Brauer, a pioneer of understanding high-pressure nervous syndrome, whilst working alongside COMEX in 1968.

Rolex Single Red Sea-Dweller
1967 Rolex Sea-Dweller ‘Single Red’ ref. 1665 without a Helium Escape Valve| Photo: Antiquorum Genève SA, 2020

The ‘Double-Red’ version of the Sea-Dweller came in 1969 when Rolex bumped up the water resistance rating to 610m – perhaps a response to Omega’s Seamaster 600 Ploprof. These models also had sturdier valves and somewhat thicker cases. Whether this was to package the valve more easily or to increase the water resistance is not known. Importantly, Rolex still hadn’t been granted the valve patent filed in late 1967 – something which only came in 1970. At this point, Rolex could actually market and sell the watch to the public.

Rolex Sea-Dweller 1665
Rolex Sea-Dweller ‘Double-Red’ ref. 1665 | Credit: Rolex/Jean-Daniel Meyer

The reasons for COMEX’s change from Omega to Rolex have been discussed at length and several hypotheses have surfaced. Firstly, there was the immense cost of Omega’s super-divers before considering that the 1000 series movements in both models were unreliable. Then, whilst brilliantly engineered, the airtight case trapped moist air after a time change in a diving bell, thus causing dial and movement degradation. The answer, as revealed by Jake Ehrlich, editor of Jake’s Rolex World, was that Rolex needed to get their Sea-Dweller in front of a bigger audience of professional divers. Inevitably, a specialist product like it had little appeal to the average buyer.

Consequently, Rolex approached COMEX offering 100 dive watches as well as appropriate repairs and servicing. This was supplemented, it is reported, with approximately another 100 watches per year from then on. This was hardly an offer to turn down and so the Rolex Sea-Dweller became the de facto COMEX watch.

COMEX in the 1970s

Rolex Submariner 5514
Rolex Submariner ref. 5514 made specifically for COMEX | Photo: Christie’s

Nonetheless, our story doesn’t end there because we still have the COMEX submariner to address – a topic with seemingly less conclusive evidence behind it. The first models offered until 1973 of the Submariner range were ref. 5513s with a retrofitted helium escape valve. After this, COMEX was given its own reference, the ref. 5514 which was a specific model conceived with the valve built-in. Whilst early models didn’t always show the COMEX logo on the dial, they were stamped in various iterations on the case back with ‘COMEX-ROLEX’.

Rolex Submariner 1680 COMEX
Rolex Submariner ref. 1680 made specifically for COMEX | Photo: ROY & SACHA DAVIDOFF SA

Interestingly, from 1978, the 5514 was replaced by a valve-less ref. 1680: the Submariner Date.  These were branded clearly with the COMEX logo and started a chain of such watches which continued to be issued to COMEX until 1997. By this stage, COMEX’s most adventurous work was covered by the Sea-Dweller. In 1992, on the HYDRA X onshore experiment, the Sea-Dweller 16600, the first to feature the cal. 3135, set a depth record of a simulated 701 metres. This achievement came 4 years after setting the wet depth record of 534 metres off the coast of Marseille with the previous reference 16660 Sea-Dweller as 6 divers completed the deepest saturation pipeline work in history. That’s quite an achievement and a hell of a testament to how much punishment such watches could take.

COMEX Hydra X 701m watches
Photo: COMEX

So, what did all this technology give the modern day diver or watch lover? Perhaps more than you think. Where Omega was concerned, the Seamaster 600 Ploprof was set to return as the Omega Seamaster Ploprof 1200M yet without the original’s innovation. Gone was the innovative crown, the helium-proof case and the 904L steel in exchange for a modern, screwed case back and helium escape valve in 316L steel. You could, of course, argue that the original crown was not suitable for Omega’s modern, luxury audience or that the monobloc case was an inconvenience. For such a niche product, though, I would argue that both may have added charm to the package.

Do not despair, though, as the innovation of Omega’s engineers in the 1970s wasn’t lost. In fact, the beneficiary was none other than Rolex. Today, this Swiss giant produces the modern Sea-Dweller DeepSea on the back of Omega’s achievement. With a crystal supported by a metal ring, the immense pressure of the abyss is transferred to the titanium case back as it was by the plastic ring of the original Ploprof. Similarly, the case back itself is formed from an inner, sealed piece clamped to the case by a screwed ring — a similar idea to the Omega’s screwing nut to seal the crown.

Meanwhile, Seiko, a brand never involved with COMEX but which developed a similar philosophy to that of Omega in the 1970s continues to produce the monobloc-cased ‘Tuna’ dive watch. In mechanical form, like the Rolex DeepSea, it is capable of resisting around 4000 metres of water above it. In short, COMEX watches and those for other diving firms continue to shape dive watch design to this day.

Head over to our dedicated column to read more or take a look at the Rolex, Omega, COMEX or Seiko websites for further information.

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