I have a diving watch with depth rating or 200 meters or about 660 feet.
here is my question…
lets say the watch would implode at 200.1 meters. I go to 200 meters exactly and started vigorously waving my arm. Would the movement increase the pressure on the watch and make the watch implode?
Basically, does movement in watch increase the pressure, if so is it a lot or a little?
Thanks H
Do you also go searching for the straw that breaks the camel’s back?
In any rating, warranty, etc., there is always wiggle room. A very small percentage of the watches will fail at less than 200 meters. The vast majority of them will perform without fail far beyond 200 meters.
Sure that is obvious, the point of the question is …
Does the vigorous movement in the water significantly increase the pressure on the watch, or is it insignificant?
Chances are: “Yes”.
As I remember it, the “200m” rating is from a short static pressure test to 20 atmospheres (10m = 1 ATM). Any dynamic presure change is quite likely be too much for it.
By the way - it won’t implode, it will just leak water in round the seals.
I was told, and I never tested it, that the potential problem isn’t so much with leaks or the case failing, it’s with the function buttons or the crown not operating properly. The pressure will force the buttons down so you can’t operated the watch properly. That’s why deep water watches use a bezel instead of a stopwatch to measure the length of a dive.
Correct me if I’m wrong.
If you’re diving to 200m, you’ve bigger issues than your watch.
Recreational dive tables don’t go anywhere near that deep, and .7 seconds of bottom time wouldn’t be worth it anyway! 
When I was watch shopping, I was informed that my 100m watch would be fine for snorkeling, but I probably shouldn’t take it scuba diving, as the dynamics would create pressures that it wouldn’t withstand. Most dive watches are rated to 200m, even though you won’t be getting nearly that deep. (Rec divers typically don’t get much below 100 ft.) They are rated to 200 static meters.
100 meters = 328 feet = dead recreational diver. You can get done there, but you won’t get back. So I think the people selling the watches don’t know what they are talking about. If the watch is good to 100 meters, it is fine for all recreational diving.
I have a Brietling dive watch rated to 250m. When it needed a new battery the store wanted something like $50 to replace the gas inside the watch (other than air). I said forget it and it has never leaked on a dive.
The point was, it may be fine to go to 100 meters if you send it down on a string nice and slow. But if you are at 20 meters, which is a reasonable depth for a rec diver, your movement will create pressures that the watch wouldn’t be able to withstand.
I’m going to post a big, “I don’t know” about this claim. It’s been many years since my physics classes, but I wonder how much atmospheric changes you can create with a minor increase in velocity?
A post on a watch website I used to frequent (TimeZone) tried to calculate the effect, for example, of falling while water skiing - would the pressure from hitting the water at 20 mph create an instantaneous pressure in excess of the watch’s rating. The result of all the math was that while there was an increase in pressure, it was minimal (I think it was compared to being 10 or 20 feet under water). So your movement underwater may increase the pressure on one side of the watch (I imagine the leeward side would have a decrease in pressure), but not enough to make any difference.
Oh, I think they know what they are talking about - in general cheap watches are rated in ‘marketing metres’, whereby 20m=splashproof, 50m=can cope with swimming, 100m=good for snorkelling, 200m=may just about survive a non-deco dive. I know my allegedly 50m proof Swatch leaked after two weeks of snorkelling, and I certainly can’t duck-dive anywhere near that deep.
Expensive watches like TAG, Breitling, Omega etc. are more likely to be able to take the pressures they advertise, but a cheap mass-manufactured watch is not likely to have the engineering to work that deep (and let’s face it, how likely is someone to complain that their Lorus crapped out at 80m instead of 200?).
However, I think this is the champ of marketing metre watches - if this leaks on you, simply take it back and demand a refund, since no-one will be able to accuse you of taking beyond its limit…
Interesting! Swiss quartz movement. How do you change the battery? The watch is only guaranteed for 12 months so do you have to replace the watch when the battery craps out?
Hey, if it leaked how would you know? It’s already filled with liquid!