Omega Seamaster 600 PloProf

Omega Seamaster 600 PloProf – 52Mondayz, week #45

Gerard Nijenbrinks
November 06, 2017
Omega Seamaster 600 PloProf – 52Mondayz, week #45

This episode of 52Mondayz is kind of a goodbye to a watch. Soon, I will say goodbye to this beautiful Omega Seamaster 600 PloProf from the first generation. But before it is that time, let me talk a bit about this iconic divers watch from the 1970s.

Omega Seamaster 600 PloProf

Omega Seamaster 600 PloProf

54mm in width, 45mm in length and 15mm thick

After four years of extensive testing Omega produced the first generation of the PloProf in the beginning of the seventies. The Compagnie Maritime d’Expertises (short Comex) and well known professional diver Jaques Cousteau were of help to Omega with developing the first waterproof watch designed and built solely for the diving professional. The watch was nicked PloProf, derived from Plongeur Professionnel which is French for Professional Diver.

A major concern with professional dive watches is the entry of helium inside the watch case. Helium is used in diving bells when professional divers have to work at greater depths for a longer period of time. Even if a regular diving watch is able to withstand a certain water pressure, helium molecules still might be able to slowly enter the watch through its gasket materials.

Omega Seamaster 600 PloProf

The red button prevents the bezel from turning unintentionally

When while surfacing the pressure drops, the helium will expand. It’s not able to leave the watch quickly enough, and the watch will get damaged by for instance popping off its glass. At that time some watch brands were testing solutions enabling the helium to escape quickly enough from the watch. A so called helium escape valve (automatic or manual) was developed and used for instance by Rolex and Doxa.

Not Omega. Omega choose to produce a watch casing which was strong enough to avoid helium to enter in the first place. they decided that it would be better to prevent helium from entering the watch in the first place. Hence the PloProf was born. Omega measured the maximum pressure the Ploprof could handle which resulted in a failure of the watch at 1370 meters (or 137 bar) as the second hand stopped due to deformation of the crystal and case. The later re-edition of the PloProf, introduced in 2009, does have a helium valve.

Omega Seamaster 600 PloProf

So far a bit of history, back to my watch. I bought this watch some 10 years ago from the first owner. He remembered having bought it very well. It was a difficult watch which sat in the shop for many years. He could acquire it with a nice discount.

However he as well mentioned that it wasn’t a watch everyone is able to wear on a daily basis. Certainly for that time (the seventies) it was a huge and very present watch. He ended up not wearing the watch very much as well, and the watch ended up with its box and papers in a drawer. Years later he took it out and decided to sell it in order to buy a watch which would suit him better for daily use.

Omega Seamaster 600 PloProf

To be honest, I didn’t wear the watch very often as well. Sometimes a few weeks, and often when attending a watch related event. The PloProf always attracts attention and is highly valued by many watch enthusiasts. But even while not wearing it on a daily basis I didn’t want to part with it.

Until now that was. Coincidentally a fellow Facebook watch group member mentioned to me that he was looking for a PloProf. At the same time I added some new pieces to my Omega Speedmaster collection. I thought this was a the right time to let it go..

Omega Seamaster 600 PloProf

A monobloc casing helps making this watch super-waterproof

We did a more in depth article on te original Ploprof here, while there’s another very informative article at John Wallis


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Gerard Nijenbrinks
About the author

Gerard Nijenbrinks

Gerard has been in the watch industry for over two decades now. He owned a watch shop in The Hague, The Netherlands, and besides that he has journalistic and photographic activities in the field of watches. Collecting watches since he... read more

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