Divers’ Watches

Why 300 is the magic number

BRICE LECHEVALIER, OF WORLD TEMPUS, THE SWISS WATCH AUTHORITY, TAKES US ON A DEEP DIVE OF
WATERPROOF-WATCH HISTORY AND SOME NOTABLE MODELS TO LOOK OUT FOR.

What do Rolex, Seiko, Panerai, Blancpain, Doxa, Hublot and Omega have in common? You might be tempted to think of the history of diving watches as a race to reach ever greater depths. But between the honourable Fifty Fathoms by Blancpain and the 10,000+ metres from Rolex, there is a world of possibilities and priorities, as we will see. On the one hand, you have incredible feats, on the other, everyday wearability. Prototypes here, versus production watches there. Civilian and military. Quartz and mechanical. There is an ocean of subtle details and choices to suit your style.

The 300m threshold
Today, a ‘divers’ watch is one that meets the specifications of the ISO 6425 standard and one of the ISO criteria is
to be water resistant to a depth of at least 100 metres (330ft). Most watches can achieve this without too much
difficulty, which is why, in reality, divers watches are generally expected to be waterproof to at least 300 metres (990ft).
It’s no coincidence that many brands have adopted this reference point for their own diving timepieces: Omega Seamaster 300, Eberhard Scafograf 300, Doxa Sub 300, Mauron Musy Armure and more.

A budget Superman
The contemporary watches we see are the result of decades of innovation. Rolex entered the race for waterproofing in 1927, followed in 1932 by Omega. Panerai joined them a few years later, during the Second World War. Nevertheless, it was a completely different watchmaker, Aquastar, that was the first to develop a watch with a depth rating of 500 metres, the Benthos 500. So, although the new 300-metre threshold is now easily achieved, due to the very small pool of buyers needing more, few brands care to aim beyond that. The one thing that did change was affordability. Yema is notable in this area, bringing out an affordable dive watch, named – perhaps confusingly – after an airborne superhero, Superman! This model has also recently been reissued and is an excellent budget choice.

A Diving Driving Force
Public interest in diving surged under the influence of one of its most charismatic heroes, Jacques Cousteau.
Not only did he make diving popular, but he also boosted the popularity of diving accessories. On the strength of
this, several watch brands brought out models that were waterproof to 300 metres or more. They included the Seiko 6215, part of the Professional 300 collection, along with the Scafograf 300 by Eberhard, followed by the Vulcain Nautical in 1970. As far as the general public was concerned, three hundred metres was now the de facto standard. The Cousteau-effect was also, perhaps, behind a renewed push for depth records, with Rolex, Omega (Ploprof) and Seiko (Prospex) the main players here.


Overcoming technical limitations
So, from a technical point of view, why 300? A simple answer is reliability of parts. Three hundred metres is the depth rating that can be achieved using the usual watch manufacturing make-up of an O-ring, standard case and screw-down crown. Progress in manufacture saw the emergence of sapphire case backs, notably on the Seamaster 300M.

Another reason why 300m is a natural seabed of ambition is that as dives get deeper different equipment comes into play. Wrist computers have become a common sight. This tech might not only render a 300m-plus watch less necessary but could also jeopardise the performance of mechanical watches through magnetic fields. Silicon escapements solved this issue, so magnetism is no longer a problem.

So, for some time now, with subtle but notable improvements along the way, watchmakers have been able to offer diving watches that can descend to 300 metres at a democratic price point. But before we clock off, we might look to the future.

A recent exception to the traditional manufacturing theories comes from Mauron Musy, a young brand that has developed an alternative to the O-ring. Its “nO-ring” technology is based on three principles, a mechanical seal, a clamp brace and a satellite compression spring. This unique solution represents a genuine paradigm shift, propelling water-resistance to the status of an “exterior complication” rather than the usual manufacturing headache.

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