Diver Watches....what gives?

I suspect most companies advise people not to dive with their watches because they aren't ISO rated dive watches, simply "dive style" watches. It also helps to protect them from angry people who misuse the watches, then blame the company because the watch failed... 

If you want an actual dive watch you need to buy something like a Marathon GSAR/TSAR, Citizen Promaster, or one of the Seiko Prospex divers. 

I also believe most tourist dives are closer to 10m rather than 40, but I'm not a diver. 

This article offers a pretty good explanation of why a 100M WR watch may not actually survive a dive to 100M. https://aquinuswatches.com/blogs/watch-expertise/how-deep-should-a-dive-watch-be.

The salient point is that the watches are tested in static water with constant pressure in laboratory conditions, and a large body of water is anything but static, with currents causing fluctuations in the water pressure. The list below is from the article and pretty much mirrors the charts I have seen on the sites of watch brands.

Watches with 3 ATM (30 meters/100 feet) are suitable for everyday use and can tolerate splashes but not recommended for swimming and diving.
Watches with 5 ATM (50 meters/165 feet) can be used daily, including bathing but not when swimming.
Watches with 10 ATM (100 meters/330 feet) are allowed for swimming and snorkeling but not for any diving.
Watches with 20 ATM (200 meters/660 feet) are perfect for any water sports activities, such as scuba or skin diving.
Watches with a range of 20 to 50 ATM (200-500 meters) is suitable when doing high impact water sports, as well as scuba and saturation diving.
Watches with 100 ATM (1000 meters) are recommended for extreme types of diving such as wreck, rebreather, and altitude diving.

Well, if it's closer to 10m, then that proves my point all the more strongly! 🤣 But you have given me a useful tidbit of information that I plan to research: ISO ratings. I had no idea that there was such a thing before now 😀 I actually have a "lefty" vintage (1990's) Citizen Promaster, or at least, my son does. (I gave it to him.) But at any rate, it's nice to know what brands/models to look for, so thanks for that info as well. 😎 You have made my neophyte journey into watch collecting just a little smoother, and I am grateful for that. 😀

Thank you so much for this very informative and insightful comment! 🙂

Rubber seals can deteriorate or become compromised over time, so I wouldn't swim or dive with a vintage watch unless it's been properly tested by a watchmaker.

https://www.fratellowatches.com/iso-6425-certification-for-divers-watches-is-it-useless/#gref

One of the best articles on ISO 6425.

Agreed, even a small amount of debris on the gasket, or an improper reassembly of the watch, can negatively affect water resistance, no matter what the number on the dial says. 

Then there is my own highly scientific method of WR testing.

In this case it is "bar rated".

Essentially a watch rated 200m or over will be fine for diving and other water activities. There are some dive watches which are rated to 100m (for example Hamilton Khaki Navy Scuba), but these are only for light water activities like swimming in the pool and nothing more than that, but you can take it skin diving making sure it has a screw down crown for safety.

In some of the brands, it will say diver's watch 200m. That means the watch is ISO rated (ISO 6425) for scuba and skin diving. There are also many versions of ISO ratings. Seiko Prospex dive watches, Citizen Promaster divers, Certina are some of the brands which make ISO-rated watches in the affordable range. 

Some brands usually skip on the ISO rating to save cost. Orient dive watches are rated to 200m but they do not have ISO rating, but they are capable. Orient Star (premium line of Orient) have ISO ratings and says diver's 200m.

If you want more capable dive watches, you need to find ones rated for saturation diving which are usually rated over 300m and over like the Seiko Marinemaster series, Rolex Sea Dweller, Omega Planet Ocean much more. 

If you want a dive watch for vacation activities, a Ecodrive Citizen Promaster or lower end Seiko Prospex models are a great option. 

While those are generally reasonable guidelines, they are based on a weak premise. People do not move fast enough in the water to generate enough dynamic pressure to overcome the seals on a watch. A 50m WR watch with good seals will not leak while swimming at/near the surface. 

The issue is usually more that watches with 30-50m WR tend to come on straps that don't do well in the water, or are watches like chronographs that can more easily be damaged by water through accidental pressing of the pushers. 

As for immersion/hand washing, theoretically the pressure in a standard household water service(50Psi) can overcome the 30m/3ATM(44Psi) seals on a watch. In practice though it's unlikely that a faucet is putting out water at 50psi, but it could happen. 

Vacation activities is EXACTLY why I want a dive watch 😎 Can't wait until summer! 😀

From what I've read in conversations with hydrological engineers, you would have to move extraordinarily fast through the water to make make any material change in the pressure.

I'd be very surprised if your "I think I want to check out diving while we're here at the resort" dive even went to 20 meters.  

There was an ongoing thread on WUS a few years ago that was the ongoing saga of someone logging dozens of dives with a 30 meter digital Casio.  It held up just fine.

Lastly, get your seals tested often.

https://www.youtube.com/watch?v=Ti-GdfGbj4Y

I like these guys, smooshing watches in a pressure chamber...

The thing to keep in mind is that unless it's ISO certified, that watch might not have actually been tested to its rated depth. It is common to test just one production watch, or a certain percentage of production watches to the depth rating. Not to test every single one off the assembly line.

The thing about having an ISO certified watch is that you know your specific watch was actually tested. If it isn't ISO certified you are dependent on the manufacturer actually doing a test. Otherwise you might have purchased one with a faulty gasket or some other problem that renders the water resistance rating moot. 

If you are buying a new watch from a reputable source I'd be confident in the accepted depth/activity charts out there (unless the manufacturer has a different chart). Anything used, I'd treat as 30m unless it was actually tested by a watchmaker.

You can also get a G-shock, they make a great summer watch. Also, 200m WR. 

I have gone scuba diving with my Omega Seamaster and also a $200 Deep Blue.  Recently went snorkeling with my Mido GMT. They were all fine, mind you i never went deeper than 15 meters and i was do an for only an hour.  

There are alternatives to ISO, but most of their names elude me at the moment, other than Dolphin. It costs manufacturers to submit for testing, which is reflected in the price of the watch, so whilst a non-certified dive watch may be fine, it’s not guaranteed to be a diver‘s watch (and get its s) just in case. It may also miss some otherwise less-apparent detail, such as a lumed mark at 3 (has a date instead) or a lumed second hand to show it is running. The reason the alternative certifications are useful/interesting is because they are usually nation based, and therefore cheaper for a manufacturer to use… but aren‘t ISO even if it’s the exact same tests. 
 

edit: also worth mentioning that most modern divers, even the homages, will outspec James Bond in the fifties, so probably not worth worrying about unless your watch cost and arm and a leg, or there is a shark involved. 

I would check with the brand about what they mean (b/c they could be slightly or more than slightly different brand to brand). Here is the link to what Seiko says about water resistance ratings on its watches (basically 5 bar ok for "swimming",  10-20 bar ok for "shallow diving",  divers 200 ok for "scuba diving", and professional divers 1000 ok for "saturation diving"):   https://www.seikowatches.com/us-en/customerservice/faq/general-information-8

Since most of us don't dive, let alone dive below the recreational 40m limit (below which decompression stops are a factor), I think 100m is more than fine for normal summer water activities short of diving and that is about as far as I have taken my dive style watches.

Of course this didn't stop me from wanting and then buying the Helm Vanuatu with my final "justification" being that each watch is individually pressure tested in water to 125% of the rated depth, you know: for the diving that I will never do. 

I also have a watch that is certified for space (and the Moon of course) just in case NASA calls. I rate my chances at ever scuba diving or space travel to be about equal.

As a frequent ocean occupant who occasionally free dives 10 or 15 feet to see what’s on the bottom - 100m is fine.  100m with a screw crown is actually the former diving standard rating.  Oris still makes divers with 100m.   It’s the watches without a screw crown and 50 or 100m that I don’t trust.  This type of watch has failed me before with water ingress with just swimming 

If you are talking about SCUBA diving…most sport diving occurs in 100 ft of water max. And 30-40 feet is very common. Nobody dives in 200-300m of water without specialized training and equipment.

your watch should be fine…

Same here. A hotel pool in Mexico still owes me a watch with 50m WR.

These are definitely worth a watch. The most interesting thing is that most of the watches fail first by having the caseback deform and pushing the movement into the crystal stopping the seconds hand. 

200m WR is generally considered a diving watch.  100m WR is considered good for activities around water, light diving etc.. 

As for diving recreational you wont be going below 30m. 

After 30m folk start getting nitrogen narcosis when breathing air and decompression penalties become pretty severe. 

Showering with a watch in hot water is a good way to degrade the seal on your watch …. No matter it’s rating .

Thank you for that tidbit of info 🙂 I actually don't shower with my watch(es) on, but when I mentioned it, I was thinking more along the lines of the kind of "shower" you get when you're chasing your kiddos around at the water park. 😎 But I had no idea about the hot water thing. Thanks! 😃

This is worth noting. The case construction matters as water pressure will act differently based on that. Compressor divers for example, are designed to do exactly that, compress when exposed to pressure. I hear Vostok's work under a similar principle.

Average digital watches, which are made of different materials and are much lighter, do not react to pressure the same as a steel mechanical watch. For that matter, your plastic 50m Timex Ironman is more likely to survive a casual surfing session than a Seiko 5KX rated for 10atm/100m. Both have no screw down crowns, the metal one is rated higher, but they both react differently to the same conditions.

The GShock recommendation is the best and safest route IMHO for most kinds of activities. If you're just lounging in a pool or boat a mechanical watch is just fine. In either case, always remember to rinse your watch in fresh water after going into salt water. If you don't the watch seals and parts in general will erode and corrode. This will definitely then guarantee your watch fails even in a shallow cup of water.

I was a padi open water diver recreationally in the nineties and personally never dived below 30m. Neither did anyone I regularly dived with.

I also used a dive computer even then and not a dive watch. I hardly remember any diver I saw actually wearing a dive watch.

I think people get hung up on ISO ratings and similar certification.

As another has commented here the standard Orient divers (not Orient star) are not ISO rated but are without doubt very capable of 200m. Vostoks likewise are not rated officially to ISO etc but are famous for going way below 200m.

It's the 30 to 50m advertised resistance where buyers need to take care IMO.

fair point 🤣

If you want to test out diving one time in the Summer most likely that The most advanced thing you’ll do is something like the PADI Open Water diving course. This is generally a 5 day course at the end of which you’re certified to dive to a depth of 18m. Even if i you tak it to the next step and become an advanced open diver the deepest you’re certified to is 30m. You can probably wear any modern 200m dive watch to that depth, the reason the brands themselves don’t say that is that they don’t actually send their watches down there they simply check to see if their watches can take 20bars of pressure in still dry air and then cover themselves. Just make sure the crown is properly secured and you’ll probably be fine (look at me covering my ass with probably). 
Another thing to think about is that if you go on a dive course now you’ll almost definitely be issued a dive computer.  I’ve never dived with a watch and treat my dive watches as fidget spinners. And for snorkling or other water sports you’ll be fine with a 100m watch unless you get really serious about free diving. Just make sure it’s got a screw down crown and if it’s not new you check the seals regularly. 

WR rating is basically a marketing ploy to get your money. Try redeeming a warranty for a water damaged watch if you don't believe me.

That's true.  Most resort dives are no more than 20-30ft.  That is where the reefs are, so that's where most of the interesting stuff to look at is.  These are the folks who would use luxury divers for diving.  Those who are going down to 80-100ft use dive computers to make sure their dives are as safe as possible.