Rolex Sea-Dweller

In the 1960s, so-called “saturation” diving made it possible to remain at great depths for extended periods. It consists of housing divers in a pressurized habitat, so as to reproduce the pressure that prevails in their underwater working environment. This means that they need only undergo a single decompression process, at the very end of the mission.

This process can damage the watch. Divers breathe a mix of gases composed mainly of helium, whose extremely fine atoms can penetrate the case. On returning to the surface, the helium trapped inside can create a phenomenon of excess internal pressure liable to compromise its integrity.

In order to overcome this problem, in 1967 Rolex introduced the Sea-Dweller, a divers’ watch with a helium escape valve. It is screwed to the case and consists of a hermetic cylinder, a piston, a gasket and a spring, acting as a safety valve. When the internal pressure in the case is too high, it opens automatically, allowing the helium atoms to escape.

The Sea-Dweller is equipped with a Triplock winding crown. This screw-down crown was invented in 1970 and comprises three waterproofness zones. It reinforces the impermeability of the Sea-Dweller’s 43 mm Oyster case, whose middle case is crafted from a solid block of Oystersteel, a particularly corrosion-resistant alloy.