The Omega Seamaster 200 SHOM, a Factoid of Exemplary Construction

                                                                                  Omega Seamaster 200 Model 166.177 Courtesy Robert Maron

If you didn’t realise its origins, a word coined by writer Norman Mailer in his 1973 autobiography of Marilyn Monroe could be mistaken as purpose-designed for the internet. He defined a ‘factoid’ as a “fact which has no existence before appearing in a magazine or newspaper”. Through repetition, these so-called ‘facts’ enter into public consciousness to become part of urban mythology and are very difficult to dislodge.

There are countless factoids pertaining to vintage Omega watches circulating on the worldwide web, devoured and regurgitated many times by people who, conceivably, are not gormless or naive, but never-the-less have taken the speculations and falsehoods of others on the Internet as the Rock of Truth.

The statement below about the Omega Seamaster 200 model 166.0177 appearing on a respected Watch blog illustrates the point:

The SHOM Seamaster was so named because Omega created this model for France's Service Hydrographique et Océanographique de la Marine (SHOM), a public agency that is charged with documenting and studying the oceans as well as supporting mariners through the publication of charts, maps, guides and almanacs. Apparently, SHOM's workers needed a sturdy, waterproof timepiece to reference as they charted, mapped and almanacked".

The ‘SHOM factoid’, that of SHOM seeking a bespoke watch to fulfil its needs and commissioning Omega to design and manufacture it, is now part of horological folklore. Like many urban myths it contains a grain of truth, albeit a microscopic one as we will discover.

What the many SHOM whisperers either don’t know or have chosen to ignore is that SHOM also acts as a technological pimp for the French Navy, testing and supplying hydrographical and other measuring instruments for use in its fleet.  Many countries use government procurement agencies for the acquisition of hardware, if not ordinance, and the French were, and are, no different

Omega designed the 166.177 as part of a range of cal 10xx Seamasters that superceded the earlier family of mid-500 caliber dive watches.The collection included the 166.250 and the 166.137 and catered for various levels of water resistance. The 166.177 made its début at Baselworld in 1973, and it was nearly six years later that SHOM entered the life and times of the Omega Seamaster 166.177

A number of Swiss Watch companies touted their dive and tool watch collections to military procurement establishments around the world and often offered substantial discounts in their tenders to sweeten a choice in their favour. The marketing potential and resulting kudos of having a product selected by the military more than compensated for such discounts.  Omega was an old hand at tendering for military contracts and was well-known for its collaborations with marine agencies since the early days of the Seamaster 300. 

When the French Navy signalled that it was looking for an ‘official’ dive watch for its frogmen (pardon the pun), Omega was probably well up in the queue to have the Seamaster 200 evaluated by SHOM as part of its tender. It won the tender, and in 1979 began supplying the 166.177 to France’s "Marine Nationale" (meaning Navy) well in to the life span of the model, as mentioned.

Normally the 166.177 case back will show the stamp ‘Tested to 200 metres’, however some pieces will have the engraving ‘MN 79’ on the case back, indicating their production after the appointment by the French Navy. This does not signify that such watches were ever in the service of the French Navy, but simply commemorates their adoption. Other official markings would need to be present before a 166.177 could be authenticated as a genuine military watch. Furthermore, it would be rare indeed to encounter an authenticated French Navy example because these watches were in service and part of the Navy’s inventory. They wouldn’t have had an easy life, and if any survived one would assume they would look far from the many pristine or well-kept examples we see on the worldwide web.

To repeat, there is no such animal as a Seamaster 200 SHOM. It is the product of the fuddled imagination of someone who attempted to make a loaf of truth out of a grain of fact.


  1. Anonymous7:14 am

    I suspect then that the 166.0177 is a service replacement case/case back in reference to the many builds being offered for sale?

    1. You are probably right on the money! The only way to tell a genuine production model and parts combination/confection is to get an extract from archives....Wehn they become available again.