In the early 1960s, Louis Brunet and the Annecy diving team, with the support of local figures such as Louis Servetaz and Mr. Bouchet, launched plans for an affordable and efficient diving watch. ZRCsales supervisor Mr. Bourdarian worked alongside Mr. Pastre and Mr. Digne, then watchmakers in Toulon, who specialized in commercial relations with the French Navy. Together, they formed a partnership to develop the Grands Fonds 300 watch.

The Grands Fonds 300 watch, His history...

Following its referencing of the first watch, the French Navy explained to the designers that the crown located at 3 o’clock posed a problem, as it was too vulnerable during underwater manipulations. It asked ZRC to « find a solution » to protect the crown without impeding wrist movement, and above all, to ensure it could not open under water. The team resumed their work and developed the famous crown at 6 o’clock, connected to the case using an exclusive system consisting of a machined canon, making the Grands Fonds the first and only watch to be equipped with a 100% single-piece case. Furthermore, the case is machined from a particular type of steel reinforced with magnesium that is completely non-magnetic: an absolute necessity for the mine clearance divers of the French Navy. ZRC developed an exclusive retractable lug specific to the space between

the horns, which only allows the crown to pass through or the strap to rotate in the closed position, making submerging the watch impossible if the crown is not fully screwed down. The strap is also original by virtue of its two extendable links, allowing the watch to be worn over a diving suit with no further adjustments. The ultra-luminescent Magnum hands ensure perfect legibility when diving. A revolutionary watch in many ways, the ZRC Grands Fonds was issued to the Paris fire service and the French waterskiing team. But it was above all the watch of the French Navy (Toulon diving school, third division of Toulon mine clearance divers, Hubert commando). A diving watch designed by divers, it was also adopted by non-military units supported by the French Navy, including the famous Calypso of Commander Cousteau, which took the watch around the world and firmly established its reputation


Vintage advertisements

A tribute to Grands fonds 300 watch

Following the success of the Grands Fonds 300, ZRC has decided to continue the adventure by re-releasing a new Swiss-made version of this revolutionary watch. Available for purchase from 2015, two models of the watch will be on offer: the re-edition, which is 100% faithful to the model produced in the 1960s for the mine clearance divers of the French Navy, and a more chic sport version, tying in with the current design trends and conventions, which has the same case, with its famous crown at 6 o’clock and bezel with luminous inserts. It is a diving watch par excellence, with great diving legibility provided by its super luminous hands, its crown at 6 o’clock protected by the CPS© (Crown Protection System), ETA movement, unidirectional notched bezel, reverse direction winding mechanism and diver’s strap.

The new Grands Fonds 300 proudly asserts its original identity. Moving from a case diameter of 36 to 40.5 mm, which is more in line with current trends, the watch has been given a domed anti-reflective sapphire crystal. The addition of chamfers to the case/strap ensemble makes it very pleasant to wear. With its clean lines and sleek esthetics, the new Grands Fonds 300 pays homage to its heritage and represents a perfect fusion of tradition and innovation.


The ECS™ is a technical solution to an issue encountered by the mine clearance divers of the Marine Nationale during their many dives: salt crystallizing in the gaps between the bezel and case, thus impeding its rotation. For the 2015 re-issue of the Grands Fonds 300, ZRC has developed and patented a functional solution – the ECS™ was born. A unique system for cleaning the inside of the bezel by circulating fresh water that dilutes and evacuates the sea salt. The ECS™ is the ultimate tribute to the original Grands Fonds and is perfectly in tune with the brand’s identity.

Patent pending number : 1462496


100% safety is guaranteed thanks to this exclusive strap system using retractable lugs. It is now impossible to place the watch in water without screwing the crown back into its original position. If the crown is not screwed down, the strap cannot be correctly repositioned. This effective method prevents oversights that can lead to technical difficulties.


The new Grands Fonds 300 is equipped with an automatic adjustable strap, which allows it to be worn over a diving suit. This unique embedded spring system automatically adapts to the diameter of the wearer’s wrist for unparalleled comfort. No adjustments are required, as two links on either side of the case extend to accommodate the new diameter.


1950-2015 : 60 years of history …

The adventure continues



The grands Fonds 300 watch

A growing community of enthusiasts forums

” a Great Fund is the result of a set of highly technical charges and everything is designed to optimize the use of which is his, the diving.”

” t is sublime with the 1st oversized needles, his telescope that I love, of course the crown at 6:00 am and steel bracelet !!!”

Here are all the links that speak of the Great grands fonds 300 watch :

Montres mécaniques Forum
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Montres mécaniques Chrono