Water resistance

There’s a common misconception: if you have a watch rated to 50m water resistance (WR), it should be good for scuba diving, right? That would make sense, but in reality you’re not safe going 17m deep with a 50m WR watch.

Many of these watches are engineered to a relatively loose standard (ISO22810) with lower tolerances and inferior water resistance designs such as a snap-on case back. They may claim to have 50m WR, but only one or two samples from the whole production batch get tested – in a vacuum. So the cases are never actually tested in water, and it’s only tested in a vacuum under perfect lab-like conditions. This standard of water resistance does not take into account the changes in seawater temperature, ageing or seals and rapid changes in water pressure.

A new watch has not been exposed to things like salt water, sweat, cologne or sunscreen. After a few months of wear those gaskets in a snap back case are going to start degrading. It’s this loophole in testing and standards that has led to watchmakers creating a new chart of water resistance, indicating which activities you can and can’t do given the stated WR rating on a watch:

50m WR You could get away with submerging it in water for a short while, but little more than that.
100m WR Good for swimming, and snorkelling.
200/300m WR Suitable for recreational scuba diving
500m WR or more Rated for more extreme diving, Saturation diving

There is a stricter standard (ISO6425) for creating a water-resistance watch however.

All our watches are tested against the immersion and pressure tests of ISO6425, but we do not record and submit our tests to ISO for verification.

  • We follow the same guidelines in terms of tolerances, case engineering and case thickness to meet ISO6425.
  • All the cases are tested in real water at the required depth to check for leaks.
  • After full assembly, the watch is then tested in a vacuum

Helium escape valve (HEV)

Our Benguela model which is rated to 500m has whats known as a helium escape valve (HEV). This is a specifically engineered valve on the side of the case which allows pent up gases from inside the case to release. These gases (helium specifically) can accumulate when the diver is spending long periods of time under pressure, such as saturation diving. Without the HEV, it is possible for the crystal of the watch to pop off and the movement become exposed to moisture and contamination.

The helium escape valve of the Benguela


A few tips

  • Avoid over-tightening the crown of your watch. This can cause wear on the seals, and over time they will perish. We recommend having the seals of your watch checked once every five years, especially if you are exposing it to moisture on a regular basis.
  • Avoid wearing your watch in the shower or bath. Exposure to soaps and steam can accelerate the penetration of water into the seals of your watch, potentially damaging the movement.