My understanding is that it is possible to apply the maximum pressure to the watch before it gets to the maximum depth, but of course I could be wrong. However a quick look at this convinces me that using a 50M rated watch and a chronograph at that is foolhardy in my opinion.
Water resistance classification[edit]
Watches are often classified by watch manufacturers by their degree of water resistance which, due to the absence of official classification standards, roughly translates to the following (1 metre ≈ 3.29 feet). These vagueries have since been superseded by ISO 22810:2010, in which "any watch on the market sold as water-resistant must satisfy ISO 22810 - regardless of the brand."
[1]
Water resistance rating Suitability Remarks
Water Resistant 3 atm or 30 m Suitable for everyday use. Splash/rain resistant.
Not suitable for showering, bathing, swimming, snorkeling, water related work, fishing, and diving.
Water Resistant 5 atm or 50 m Suitable for everyday use. Splash/rain resistant.
Not suitable for showering, bathing, swimming, snorkeling, water related work, fishing, and diving.
Water Resistant 10 atm or 100 m Suitable for recreational surfing, swimming, snorkeling, sailing and water sports.
Not suitable for diving.
Water Resistant 20 atm or 200 m Suitable for professional marine activity, serious surface water sports and skin diving. Suitable for skin diving.
, but does anyone know if the pushers need to be completely pressed down to allow for water intrusion or do they just need to pushed a little to allow moisture in? For example, would the chrono need to be started underwater or would a simple wrist bend pressing on the pusher cause leakage?
