Omega and the PloProf Research Programme – Innovation in Professional Dive watches (incl. Pioneering use of 904L Steel for Watches)

By rolex
May 27, 2021
7 min read

By the mid 1940s, Emile Gagnan and Jacques-Yves Cousteau’s Aqualung – the main commercially effective independent underwater breathing apparatus (a.k.a Scuba)-   had become an overall phenomenon. Along with the growing prevalence of recreational diving, the needs of military and professional divers underscored the paramount importance of solid underwater instruments. The principal modern plunge watches showed up in the mid 1950s with the Blancpain Fifty Fathoms, the Zodiac Sea Wolf or the Rolex Submariner. Created in 1953, the Blancpain Fifty Fathoms is often viewed as the model of the jump watch: a robust, exceptionally clear watch, water-resistant to incredible profundities (91 meters, in this instance) and outfitted with a unidirectional rotating bezel to time dives.

The development of remote ocean saturation diving

However, the development of remote ocean saturation diving soon made even higher performing devices necessary – basically because professional plunge watches had to adapt to the evolution of diving techniques.

Saturation diving truly began in the last part of the 1950s and the main commercial jumps were acted during the 1960s. It permits professional divers to live and work under important degrees of pressing factor for quite a long time or weeks. Subsequent to working in the water, the divers live and rest in a dry compressed environment on a diving support vessel or stage, aligned to a similar pressing factor as the work depth.  The underwater work groups are compressed to the working pressing factor and decompressed just once, thus limiting the dangers related with decompression to a single exposure.

Saturation diving is dangerous; when divers are presented to increased pressing factors for quite some time, their tissues gradually get soaked with inert gases and these need to be delivered gradually during the decompression phases of the ascent. It is exceptionally technical and there is no margin for the smallest blunder. The need for exact and solid watches that could perform at incredible profundities turned into an immeasurably significant issue. In this context, professional divers worked with watchmakers to create watches with extraordinary specifications. Among them, the COMEX is celebrated for cooperating with manufacturers like Omega and Rolex.

The Omega Seamaster professional watches

Although the Omega Seamaster was born in 1948, it turned into a genuine jump watch in 1957 with the creation of the three professional ranges: Seamaster, Railmaster and Speedmaster. With the arrival of reference CK2913, the Seamaster accepted all the ascribes of the modern jump watch: profound water resistance rating, a rotating bezel, high neatness, etc…

A few years after the fact, in 1968, with the development of saturation diving, Omega began to help out the COMEX to grow even more extraordinary watches. Saturation diving was as yet in experimental stages. With the French diving expert company, the brand was involved in a colossal exploration project, Ploprof, to build up the most ideal watch for remote ocean saturation diving, for professional use only. (Editor’s note, Ploprof stands for Plongeur Professionel, Professional Diver in French). The COMEX used Omega watches for testing on both its Physalie (1968-1972) and Janus (1968-1977) programs. By 1968, Omega had created two kinds of prototypes following similar requirement specifications. Two Ploprof projects coded internally ‘Ploprof 0’ and ‘Ploprof 1’ that would at last become commercial models.

Managing decompression

Among the stringent requirements of the Ploprof projects, decompression for saturation diving was a significant issue. As divers go further and more profound, pressure renders the air poisonous and divers need to inhale different gas combinations immersed with helium to prevent the risk of inert gas narcosis. As one of the littlest elements, helium can penetrate a watch where water or oxygen cannot. During a profound jump, the pressing factor inside the watch gradually rises to that of the vessel/ringer. During the ascent, the reversion to surface pressing factor can eventually cause the gem to pop off.

Several approaches were conceived to address this issue. In the last part of the 1960s, Rolex and Doxa dealt with the helium help valve (HRV) a sharp solution to enable the strain to escape consequently when the difference between the inner and external pressing factor ascends to a basic level. Be that as it may, the addition of a HRV comes with a disadvantage. It adds another opening in the watch case: another point that may influence its water-resistance.

Watchmakers additionally dealt with case designs to prevent the glass from popping off. (The Seamaster 300 CK2913 itself gave an interesting solution. Its hesalite glass highlighted a level edge and was inserted from the caseback and then maintained by a ring screwed from the caseback as well. With this construction, the gem isn’t held set up by pressure and hence it cannot pop out).

If you don’t give helium access, you needn’t bother with a HRV. This is basic, legitimate however more difficult than one might expect. To make an impenetrable case, Omega chose to machine a Monobloc case. The point was to keep the points through which helium may enter a case to a minimum

Ploprof 1 – Seamaster 600

The Ploprof 1 prototype brought forth the Seamaster 600 Plongeur Professionel, the PloProf as far as we might be concerned today. The model appeared commercially in 1971/1972. This monster of a plunge watch was 55mm x 13.5mm and stood apart with its hilter kilter design and its monobloc case construction that would not let any gas in.

The PloProf was evaluated water-resistant to 600m yet was tried to pressures exceeding 1,300m. Among its other unique qualities was its artificially hardened mineral glass, its dial format and its bezel locking gadget. The bezel is bi-directional however it can only be turned while pressing the red pusher.

Pioneering the use of 904L steel for watches

The materials and metals used to art a particularly avant-garde watch were of paramount importance. The Comex divers working in amazingly destructive environments (explicitly for oil drilling) required a watch made from a profoundly resistant metal. Omega attempted a few materials (included titanium!) and ended up crafting the Ploprof out of .

This innovative composite is entirely appropriate for seaward and subsea industries. Uranus steel was likewise used by Comex to create apparatuses that would be profoundly resistant to seawater corrosion and forceful environments. Today, it is better known under the name Inox 904L, the sort of combination used by Rolex toward the end of the 1980s. For additional subtleties on this theme, check our video distributed a couple of days prior: the Seamaster Chronicles, Part 1 .

Ploprof 0 – Seamaster 1000

The second Ploprof project – named internally as ‘Ploprof 0’ at Omega – is less known and was really the first! It was truth be told built up a couple of months before the Ploprof 1 and would conceive an offspring during the 1970s to one of the most uncommon and generally sought-after Seamaster watches, 

Engineered for saturation professional diving

The ‘Ploprof 0’ shares many attributes with the Seamaster 600. Everything about this instrument/professional programmed jump watch had a utilitarian reason. The huge steel case was a monobloc construction, 38mm from 9 to 3 o’clock, 54mm from 12 to 6 o’clock. The thick mineral precious stone of the prototype was made from two separate parts that were subsequently connected safely together. Like this, the complicated type of the precious stone’s profile could be manufactured effortlessly. The precious stone itself was gotten to the situation by a ring from the top. The crown was positioned to one side of the case to evade any unwanted operations underwater while allowing the wrist to move unreservedly. While the case for the commercialized models would be bended for enhanced ergonomics, the prototype actually included a level case with a scored anti-slip back. The bezel was rotatable with a no-decompression graduation in metres.

The high contrast dial highlighted tritium-covered markers. The minute hand was the most prominent hand because this is the only important one. The short central seconds hands, featured in orange, had no other utility than to watch that the watch was running.


Sincere thanks to Petros Protopapas and the Omega Museum group for their help.