I've got one of those Casio Wave Ceptor from wally world that resets itself everynight for about $40 and never had a problem. Curiously, the watch is rated at 50M, but the back of the casing says it's rated for 5 bar, which isn't the same. Somebody didn't think that thru. On a side note, a friend of mine has a $5k rolex dive watch. Rated to like infinity or some equally large number. Looks sharp. But will he dive with it? No. He doesn't want to lose it. I thought to myself, just get a knockoff if you like that look that's rated good enough to shower in.
Water resistance ratings for watches
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hudson
Contributor
The dynamic pressure formula is:
pressure (pascals)=0.5 * density of water (kg/m^3)* speed ^2 (m/s)
Approximately, assuming a speed of, say, 2m/s:
0.5 * 1000 * 4 = 2000 pascals = 0.3 psi
Total pressure is static pressure + dynamic pressure. So unless I'm missing something (very possible) I don't see how this affects anything even if you increase velocity significantly.
pressure (pascals)=0.5 * density of water (kg/m^3)* speed ^2 (m/s)
Approximately, assuming a speed of, say, 2m/s:
0.5 * 1000 * 4 = 2000 pascals = 0.3 psi
Total pressure is static pressure + dynamic pressure. So unless I'm missing something (very possible) I don't see how this affects anything even if you increase velocity significantly.
CycloneFever
Registered
Hey everyone. I'm not much of a SCUBA diver (yet) but I've been a watch enthusiast for a while. I've got a few comments.
One. Even in the watch community we can't figure exactly why you shouldn't dive with a watch rated for say 100m. There are tons of things that affect water resistance ratings. One of the key things is that the rating assumes a watch in perfect condition. They all have seals, etc. that can degrade over time. You are also recommended to periodically have your watch pressure tested although no one does. Mainly for these reasons I think the conventional wisdom is pretty conservative, at least relative to the specified resistance ratings.
Two. Thirty seconds per day accuracy out of a mechanical watch is indeed pretty poor. Even a pretty low quality mechanical movement should perform that well and can be regulated to perform better. High quality movements can perform within COSC standards of -4/+6 seconds per day. (This is typical of Omega, Rolex, etc.) I have a Longine (vintage Ultra-Chron) that was originally guaranteed (40 years ago) to be within 1 minute per month (2 seconds per day). If it was a quartz (or kinetic, or eco-drive) it should be thrown out with that kind of accuracy.
Three. Dynamic pressures are not one of the factors that go into water resistance and the apparent discrepancy between ratings and described usage. Hudson beat me to it but as I once posted on a watch discussion board:
That being said, I would generally accept the following conservative recommendations:
<100m don't submerge
100m swim/snorkel
200m recreational SCUBA
300m anything goes
One. Even in the watch community we can't figure exactly why you shouldn't dive with a watch rated for say 100m. There are tons of things that affect water resistance ratings. One of the key things is that the rating assumes a watch in perfect condition. They all have seals, etc. that can degrade over time. You are also recommended to periodically have your watch pressure tested although no one does. Mainly for these reasons I think the conventional wisdom is pretty conservative, at least relative to the specified resistance ratings.
Two. Thirty seconds per day accuracy out of a mechanical watch is indeed pretty poor. Even a pretty low quality mechanical movement should perform that well and can be regulated to perform better. High quality movements can perform within COSC standards of -4/+6 seconds per day. (This is typical of Omega, Rolex, etc.) I have a Longine (vintage Ultra-Chron) that was originally guaranteed (40 years ago) to be within 1 minute per month (2 seconds per day). If it was a quartz (or kinetic, or eco-drive) it should be thrown out with that kind of accuracy.
Three. Dynamic pressures are not one of the factors that go into water resistance and the apparent discrepancy between ratings and described usage. Hudson beat me to it but as I once posted on a watch discussion board:
CycloneFever on Watchuseek:
That being said, I would generally accept the following conservative recommendations:
<100m don't submerge
100m swim/snorkel
200m recreational SCUBA
300m anything goes
OP
NudeDiver
Contributor
CF:
Great post. I'm a "fan" of watches, fountain pens, and similar kinds of things - but not a very educated one.
In your watch world, what's the buzz on watches with the WR rated in bars, rather than meters (or feet I guess)? Is this just an older way of doing it, a different way of doing it, or does it signify anything else (such as yeah, sure, go diving with this thing)?
For example, my Seiko Kinetic, which is not a diver's model, indicates, "water resistant to 10 bar". Any significance to using bar rather than meters there?
Thanks!
nd
Great post. I'm a "fan" of watches, fountain pens, and similar kinds of things - but not a very educated one.
In your watch world, what's the buzz on watches with the WR rated in bars, rather than meters (or feet I guess)? Is this just an older way of doing it, a different way of doing it, or does it signify anything else (such as yeah, sure, go diving with this thing)?
For example, my Seiko Kinetic, which is not a diver's model, indicates, "water resistant to 10 bar". Any significance to using bar rather than meters there?
Thanks!
nd
sourcearun
Registered
In my experience it's pretty common to get a static pressure test done when you have the battery changed (or the case opened for whatever reason) at a dealer/repair shop - I know I do
CycloneFever
Registered
There's not really any significance to it. I think it's mostly done as a 'cool' or 'different' factor. There's no technical difference that I know of. Many times they have multiple ratings marked on them somewhere. Sometimes markings on the dial and the back of the case are different (though equivalent). Of course 1 atm = 1 bar = 10 meters = 33 feet.
Just out of curiousity, I did a survey of my collection. (Small by collection standards and not all divers.) They're rated as:
5 atm
30 m
unrated (although IIRC the specs call for 50 m)
200 m
200 m
200 m
300m / 1000 ft
660 ft / 200 m
300 m / 1000 ft
300 m / 30 atm / 1000 ft
CycloneFever
Registered
That could be. I guess I was thinking of things from my own angle (I don't have any watches requiring battery changes.)
Air On
Guest
I started reading through and just thought I'd jump to the end so forgive if i repeat something...
Water resistant is NOT water proof. Granted you could put over 20 of them on your BC for less then half the price of the 1 water proof watche... The odds are most of them would not fail.
If you are depending on the watch for your dive timer then you do not want water resistant though... If its a backup timer, then thats fine. If you depend on it... Whats your life and health worth? You decide.
I have both types, my first purchace was a $7 dime store digital I strapped to my BC as a backup. Its been diving with my since I started and hasn't leaked yet. mostly because I don't push its buttons at depth. If your doing deep dives to 100 feet though, I wouldn't advise the cheaper watches.
I also have a nice waterproof, sealed dive watch my wife gave me as a gift. Its a cool looking titanium case that sealed with a screwdown winder and a cool dive helm stamped into the back of it. The brand excapes me at the moment...
It does stick up about 1/2" to 3/4" off my arm and does catch on things...
Its a very nice dive watch though with a large enough wrist band to go around my suit and gloves. Granted I always forget to take it off before I pull my arm out of the wet suit and get stuck at the wrist all the time...lol
I WOULD count on the expensive dive watch to dive tables etc on a trip... the dime store watch was a stop gap measure until I could afford the other watch and is only a backup for my dive computer having a critical falure.
I also have a cheap camping compass that goes down with me in addition to my expensive Sunnto add on one i was able to afford later. Its liquid filled so it shouldn't ever collapse at depth.
I also started out with disposable water cameras rated to 30 feet (Though they work at 50 feet and new ones are rated to 50 feet). I was able to get a bunch of really cool pictures with them from dive trips. They float pretty hard though and seem to get in the way, when most dive equipment hangs down instead...
I now have a nice DC800 Sea Life camera (no strobes yet though) that I love... At its price though I cringe every time I get it wet... The disposable would be a loss of under $15 the digital over $400...
Now I still prefer my $40 black rubber fins, even though I added heel springs that cost more then the fins did...lol I've been thinkning about buying some new fins but these old school ones work VERY well and the price differnce is hard to justify for me.
On the other hand I have a dive flare by Princeton that is a POS... it always floods (they replaced 3-4 times now) and I always have to fall back to one of the light sticks I carry for my rescue sausage. (I recycle the chem lights by the way) So in that instance cheaper has been better. I'm looking at Glo-Tubes currently to replace the Princton eco flare.
My point is, get what you can afford thats safest, you'll be buying more and upgrade as you explore your interests anyow. You've got to start someplace.
Water resistant is NOT water proof. Granted you could put over 20 of them on your BC for less then half the price of the 1 water proof watche... The odds are most of them would not fail.
If you are depending on the watch for your dive timer then you do not want water resistant though... If its a backup timer, then thats fine. If you depend on it... Whats your life and health worth? You decide.
I have both types, my first purchace was a $7 dime store digital I strapped to my BC as a backup. Its been diving with my since I started and hasn't leaked yet. mostly because I don't push its buttons at depth. If your doing deep dives to 100 feet though, I wouldn't advise the cheaper watches.
I also have a nice waterproof, sealed dive watch my wife gave me as a gift. Its a cool looking titanium case that sealed with a screwdown winder and a cool dive helm stamped into the back of it. The brand excapes me at the moment...
It does stick up about 1/2" to 3/4" off my arm and does catch on things...
Its a very nice dive watch though with a large enough wrist band to go around my suit and gloves. Granted I always forget to take it off before I pull my arm out of the wet suit and get stuck at the wrist all the time...lol
I WOULD count on the expensive dive watch to dive tables etc on a trip... the dime store watch was a stop gap measure until I could afford the other watch and is only a backup for my dive computer having a critical falure.
I also have a cheap camping compass that goes down with me in addition to my expensive Sunnto add on one i was able to afford later. Its liquid filled so it shouldn't ever collapse at depth.
I also started out with disposable water cameras rated to 30 feet (Though they work at 50 feet and new ones are rated to 50 feet). I was able to get a bunch of really cool pictures with them from dive trips. They float pretty hard though and seem to get in the way, when most dive equipment hangs down instead...
I now have a nice DC800 Sea Life camera (no strobes yet though) that I love... At its price though I cringe every time I get it wet... The disposable would be a loss of under $15 the digital over $400...
Now I still prefer my $40 black rubber fins, even though I added heel springs that cost more then the fins did...lol I've been thinkning about buying some new fins but these old school ones work VERY well and the price differnce is hard to justify for me.
On the other hand I have a dive flare by Princeton that is a POS... it always floods (they replaced 3-4 times now) and I always have to fall back to one of the light sticks I carry for my rescue sausage. (I recycle the chem lights by the way) So in that instance cheaper has been better. I'm looking at Glo-Tubes currently to replace the Princton eco flare.
My point is, get what you can afford thats safest, you'll be buying more and upgrade as you explore your interests anyow. You've got to start someplace.
OP
NudeDiver
Contributor
I still dunno why this turned into a conversation about cost issues.
Suppose it is a nice $1000 watch and he says on the case, "Waterproof to 500m - read manual for details". Then, when you read the manual, it says, "for use around kitchen sinks and swimming pools. Do not use when SCUBA diving." Then what?
The intent of raising the OP was about ratings, what they say, and what they mean - not an issue of cost. No matter HOW much you pay, if the rating alone cannot be trusted to mean what it actually says (within reason), then that's a problem in my view. I'd think its misleading labeling, or false advertising - and while I'm a hater of government, it should be prevented by one or more government agencies.
Personally, I think the concepts of "water resistant" and "to 50 feet" (let alone, meters) are incompatible. To most people, at least anyone I know, "water resistant" is referring to getting splashed, or at most, submersed in a few feet of water. To use that term for something with anything even close to a 50m rating (let alone beyond that) is simply misleading - hell, it's even false!
I don't like it. So, I'll bitch about it. So there. Nah ne nah nah nee nee.
Suppose it is a nice $1000 watch and he says on the case, "Waterproof to 500m - read manual for details". Then, when you read the manual, it says, "for use around kitchen sinks and swimming pools. Do not use when SCUBA diving." Then what?
The intent of raising the OP was about ratings, what they say, and what they mean - not an issue of cost. No matter HOW much you pay, if the rating alone cannot be trusted to mean what it actually says (within reason), then that's a problem in my view. I'd think its misleading labeling, or false advertising - and while I'm a hater of government, it should be prevented by one or more government agencies.
Personally, I think the concepts of "water resistant" and "to 50 feet" (let alone, meters) are incompatible. To most people, at least anyone I know, "water resistant" is referring to getting splashed, or at most, submersed in a few feet of water. To use that term for something with anything even close to a 50m rating (let alone beyond that) is simply misleading - hell, it's even false!
I don't like it. So, I'll bitch about it. So there. Nah ne nah nah nee nee.
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