diving watches... the meaning of bar?

we were discussing diving watches at work today and somebody pointed out that my AT2000 goes deeper than the human body can stand. this may be true, or not but it got us onto the Deep Two which states that it goes to 12bar.
is this correct, as 12bar is only approx 120metres? i would have thought the Deep Two would handle more depth than the AT2000?
stephen

I am sure MF will correct me if I am

wrong, but I believe the reason for the large discrepancy is that the AT 2000 has only to withstand the pressure of being that deep in the water whereas the Deep Two has a very intricate and sophisticated indicator which is only designed to register to a specific depth with the stated accuracy. As such the mechanism in the Deep Two must perform while the AT 2000 really only has to tell time and not implode.

diving watches...

Hi Stephen,

A simple rule to calculate depth in meters is : 1bar=10meters down.
Aquatimer DeepTwo can handle 12bar=120m
Aquatimer Auto 2000 can handle 200bar=2000m

Meters and movement

I thought that the meters down the water a watch can stand, like 30 meters, is true as long as the watch is not moved too much while being in the water. When mowing with your arms fiercefully, like when swimming vehemently, a watch could be in danger because of the pressure built up by the movement. The same is true when keeping the watch under the tap while the water flows with some pressure: again, the watch may be in danger. This is the reason that when one likes to swim, a watch standing 120 meters seems OK while with a watch standing 30 meters you take a risk.

Kind regards,
Paul, wearing rose gold VC Portuguese, that doesn't like water because of the above, and the leather strap

Thank you for correcting this

I apparently missed this post. And indeed at other places at the start of the holiday season people were warned to let the seals of their watches be checked before giving the watch some water action. That should take the troubles away for more than 99%.

Kind regards,
Paul, wearing steel VC Pilot's watch

Corection to BAR / Depth here...

1 ATM (Bar) is the pressure we have at sea level and as a generalization (note: there is a difference in Salt water v. Fresh Water) the pressure increase 1 ATM for every ten metres of depth. So at 10m depth, the pressure is generally said to be 2 BAR. < 20m=3 Bar, 30m=4 BAR etc. etc. Since the human body is made up for a large percentage of fluids and cells containing fluids and the surounding pressure has little effect (inability to compress) fluids, the issue is (as is the case with watches) the open air cavities within the "body". Currently Free Divers (no scuba) are breaking the 210m depth record, but can do that as the human body adjusts, and blood plasma fills up blood vessels in the lung while reducing the volume. Without this adaptation, the lungs would be compacted/shrink and a colapsed lung (= mostly permanent damage), would be proable already at 25-30 meters. The same for watches. While your watch could be rated to 30 BAR (so 310m) depth, as long as it has air in it - sooner or later the O-Rings and/or Saphire glass will sucumb to the pressure if you succeed that rating. IWC watches would probably have a fair margin of "safety" over the stated limit due to the high quality of manufacture, fit and quality, but would you risk it? Not me - so dont go testing it unless you have a real need to do so, and use the aquatimer as a mechainical backup only for safety - within the specifications.

Thank you for correcting my comment (nt)

diving with IWC

Although I read the posts with interest,
I must say that despite owning an 3536 and 3719 and are a frequent "holiday" diver (I dive on vacations when possible). I never felt the need to take an IWC with me in the water. While showering I even take them of... Although I´m convinced they´ll do fine it is just to precious to take along, while nowadays all the diving computers on your console provide time...
Perhaps I cherish my watches to much...
best regards
Bas Dekkers
wearing an MarkXII today.

diving with IWC - Simply DO IT !! ....

Bas, I understand the sentiment but to be honest, IWC build AquaTimers to be just that - the ultimate dive backup safety timer for sport divers. In my opinion, as long as the watch is reguarly serviced, then dive with it and have the comfort and safety of a mechanical backup. After all, you have your regulator serviced reguarly too (or trust the dive centre hire shop did) and then you rely on that service to keep it working correctly. I've put hundreds of dives on my AT, and never an issue. Treat it right, service it regulary, dive within the limits and it will give you hours of extra pleasure.
mvg
Mark

okay, you've convinced me..

okay, you've convinced me..
I'll have a go this summer (pictures to come).
cheers
Bas

PS still feeling a bit nervous