Grands Fonds 300

The Grands Fonds was born at the end of the 1950s, when ZRC — until then known mainly for its expanding bracelets — became involved in supplying water-resistant cases for dive watches intended for the French Navy. The first Grands Fonds 300 took shape around 1960: a rugged case designed to withstand the pressure of the depths and the operational use of military divers.

The decisive leap came in 1964, when the Navy reported a concrete problem to ZRC: the crown positioned at 3 o'clock, as on almost all watches of the time, was too exposed during underwater manoeuvres. ZRC responded by moving the crown to 6 o'clock and integrating it into an exclusive protection system, within a monobloc steel case reinforced with molybdenum to provide antimagnetic resistance — an important requirement for divers engaged in clearing explosive ordnance. From then until 1995 the Grands Fonds 300 was officially issued to the Navy's diving school, the minesweeping groups and Commando Hubert; it was also worn by the Paris fire brigade and, according to several sources, by the divers of Jacques Cousteau's expedition.

After a long period in which the brand focused on other activities, the Brunet family — descendants of the founders — relaunched the Grands Fonds 300 from 2014-2015, restoring the proportions and spirit of the original but with modern movements and materials. Today it remains ZRC's emblematic model, the reference point from which the other collections of the Grands Fonds family derive, including editions dedicated to the Navy and to today's underwater forces.