[Samsung Galaxy Note 8 Guides, News, & Discussion] Ryland Johnson:
Quote

"DEEPSEA TEST TANK

Extreme depths

To guarantee the water resistance of the Rolex Deepsea divers' watch to the extreme depth of 3,900 metres (12,800 feet), Rolex tests every single one made in a specially designed high-performance tank. This stainless steel hyperbaric tank is cast in a single piece and weighs 1.3 tonnes. It simulates the pressure at 4,875 metres (16,000 feet) below sea level, some 25 percent greater than the depth indicated on the dial. At this depth, the force exerted upon the watch is equivalent to a weight of 4.5 tonnes. This test could be destructive, meaning that the slightest weakness in a watch would cause it to implode. Obviously, all Rolex Deepsea watches offered for sale have survived it."

This is one of a handful of watches that are so tested in official labs with highly qualified engineers.

I will now show the official watch industry water resistance table:

....................................................................................................................................

"Water resistance classification

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 These vagueries have since been superseded by ISO 22810:2010, in which "any watch on the market sold as water-resistant must satisfy ISO 22810 – regardless of the brand." [5]

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 swimming, white water rafting, and fishing.	Not suitable for diving and snorkeling.

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.

Diver's 100 m	Minimum ISO standard (ISO 6425) for scuba diving at depths not suitable for saturation diving.	Diver's 100 m and 150 m watches are generally old(er) watches.

Diver's 200 m or 300 m	Suitable for scuba diving at depths not suitable for saturation diving.	Typical ratings for contemporary diver's watches.

Diver's 300+ m for mixed-gas diving	Suitable for saturation diving (helium enriched environment).	Watches designed for mixed-gas diving will have the DIVER'S WATCH xxx M FOR MIXED-GAS DIVING additional marking to point this out."

....................................................................................................................................

As you can read "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." Rating 30M yet its only splash proof!

and.....

"Water Resistant 20 atm or 200 m. Suitable for professional marine activity, serious surface water sports and skin diving. Suitable for skin diving." Rating 200M yet in reality only fir for water sports and skin diving!

From this one can clearly see how the actual rating on the rear of ones watch is a complete joke.

A handful are exceptions like yours that is why I asked you about it. I come from a family of horologists and though watches are another one of my vices I am not a horologist myself. I have been saying for decades how the watch industry screws the consumer with these highly misleading water resistance ratings etched onto the rear of the case.

Same principle applies to our mobiles. The ratings are very VERY misleading. Add to that sea water or swimming pool water and the chemicals or salt will, over time, ruin the water resistant membranes of the mobile.

I will not start to write about the physics of static water pressure at small depths V water pressure at immersion levels when force of movement is added such as a swimmers arm. Swimming with a mobile places immense pressure on the device even at 1" depth. This is due to water pressure through movement not static depth. Enough already.

The best respectful advice I would give any mobile owner is to treat the 'water resistance' as merely splash or wet hand proof. Nothing more. Its a complex situation. Original Sony Z owners know all about it lol. Sony lost a massive client base over that fiasco and Sony themselves considered closing their mobile division.

Ryland