not getting the views you hoped for from the other (identical) thread/video?

 

Yes Sir.
I believe it's a subject worth discussing and I didn't have much luck in the Public Section. I have only ever come across one video that similarly explains this subject, but is 20 mins long and I found it a bit difficult to follow (excellent explanations, maybe lack of better graphic effects/ and overall length)
I understand this video contains references to a project of mine that I have been working for a while now. But that's also the very same reasons I've come to understand watches water resistance more in depth, so they are inevitably linked together.

I sincerely hope you won't find this unfair and the reason is designing an automatic watch that is capable of withstanding 20ATM at 11.50mm thick (with a domed sapphire crystal) was no easy task, and with many extra costs 😅
Informing the community that a 3ATM is more than adequate for 99% of the people out there (when comes to diving/swimming) is certainly not doing me any favours, but I thought the community deserved a fair, unbiased explanation regardless.

Hoping this clear the reasons behind this fully 👍


edit. If this is unfair or goes against any of the forum's rule, please let me know and I will ask a Moderator to remove this thread. My passion for watches and the respect for this forum and its rules comes always first.

 

here's the thing, I just don't go to videos from here, never sure of the link and don't like to be click baited into giving someone eyeballs. It's just me (maybe) but I generally ignore the self-promotional stuff.

regarding the point of your video, I'd rather read it here, I really prefer learning by reading than watching a video. I have no issues with WR ratings, or how they are arrived at. As a rule I follow what ever the manufacturer says since they're the ones that will fix it if a problem develops while abiding by their guidelines.

as for informing the community, good luck with that. there are people here who will proudly tell you they will not take their (somewhat) pricey (to them) 300m WR dive watch into the ocean and will instead use a cheaper one because...yeah I got nothing. anyway many will argue that what you say is all well and good but they're not going to risk their watch on what you have to say. let's face it, people still believe in a flat earth, science is false and vaccines are ineffective. good luck convincing them with facts and evidence that they're safe with their 3atm wr el expensivo watcho

 

Yes of course. I understand people did spoil the opportunity of sharing information and videos, by flooding the net with nonsensical stuff before.
I much prefer reading myself.
Attached here please find my chart with the basic formulas and examples I have used for the video. Should you wish, please feel free to consult it.

Please allow me a few moments to edit my first post, I shall add these pictures here with an explanation at the top.

As per people and their watches, I personally feel I am no one to judge on that. Also we all perceive things differently, so I've never really thought about changing people's mind... Maybe more trying to help those who are willing to learn new things 😅

Thank you kindly for the feedback 👍

 

WR has been well and truly done to death.

If a manufacturer tells me my under warranty watch is not suitable for immersion in water then it will not be covered if I then choose to do so.

Argue as much as you like about it, it’s a risk, are you risk averse enough to chance it?

Answer yes….go diving.

Answer no…leave it at home and put on a dive watch that says 20atm on the back.

 

I see where you are coming from and I totally understand that.
Personally I am not going to throw what a manufacturer warrant should cover or shouldn't in the mix, as is not my place to say.

I think most of the confusion is also actually caused by that, so with this thread I was just hoping to explain some dynamic pressure insights and how it effects watches (from 3ATM pressure tested)
How people decide use their own watches will always be a decision I am going to respect, as we all inevitably tend to perceive things differently.
Still well worth to discuss, not only because I love a good ol' chat about watches, but because this is a subject that we often see there is a lot of confusion.

 

In my opinion, this discussion is being held in the wrong forum, because this is supposed to be about diving watches and a watch with a pressure resistance of 3 bar / 30 m cannot be a diving watch by definition.

1 Scope of application
This standard applies to watches designated as diving watches, regardless of whether they are used for recreational or professional diving.
It applies to diving watches for diving depths 𝐿
𝐿 = 100, 200, ... m.
Only full 100 m values may be indicated. Intermediate values are not permitted.

Source: DIN 8306 / ISO 6425


But apart from that, the topic of “water resistance” has already been discussed here to excess.

 

In my opinion, this discussion is being held in the wrong forum, because this is supposed to be about diving watches and a watch with a pressure resistance of 3 bar / 30 m cannot be a diving watch by definition.


Source: DIN 8306 / ISO 6425


But apart from that, the topic of “water resistance” has already been discussed here to excess.

Absolutely! A professional diving watch cannot be anything less than 10ATM resistant.
However the 3ATM is merely a a comparison number I have used with the dynamic pressure formulas.

This thread isn't about replacing a professional diving watch with something else.
Just looking at dynamic pressure and how it relates to static pressure, and 3ATM was the chosen sample.

I understand this has been discussed before, however I have not come across a more simple mathematical explanation (with real life examples) on this forum.
I did see another thread with some formulas, but I found it rather complex to digest and lacked some of the examples I brought in.

 

I really appreciate your scientific approach to this age old question. But, it leaves me wondering and I have even more questions now.

1. Assuming a watch is rated at 3 ATM at the factory, that is under static ideal conditions with new gaskets. What happens when the gaskets are a year old? Don't they deteriorate over time? That's why pretty much all manufacturers suggest to have water sealing checked once a year right?
2. What about temperature? How does that affect the gaskets and water tightness? What if the watch is cold versus warm? Does that affect the depth rating?
3. Your calculations for dynamic pressure, I assume, are for an instant in time. What happens to the water tightness assuming you are hitting the water at 16 m/s and then plunging to some depth after that?
4. Does angle of attack matter? i.e. Where is the gasket the weakest and does that matter in a static versus dynamic pressure situation?

I am NOT a chemical engineer with expertise in fluid dynamics but as a lay person, these are just some of the questions that come to my mind.

 

Hi fc3861!
Thank you for taking our time to appreciate the efforts made behind this thread! And thanks for the questions!!!

1. Static "ideal" conditions when looking at the examples we brought in, are actually harsher than the "dynamic conditions" examples we discussed!
Look at it this way, 3ATM equals, more or less depending on salinity, temperature of the water etc... to diving at 30M below the water surface. In other words, that means that the pressure is coming from ALL that water on top of your head! The way you will be experience pressure when diving is of course different, that's because the pressure will be exerted equally from all direction (not just from above you).
Not my words but a very effective explanation, and I quote: "In a fluid, pressure from above and below caused by gravity also forces the fluid or gas to push in all directions, as it seeks to fill areas of lower pressure"

Moving to the gasket question, rubber does perish overtime. Some manufacturer advice people to do extraordinary maintenance when using a watch for professional diving (every year instead of three) and I agree.

2. Temperature does play a role on everything. Not just the gaskets. It will of course have an impact on the density of a fluid, the gaskets, the expansion and contraction of the watch case (either plastic, steel etc) BUT normally this temperature variation aren't extreme to the point they will have a significant impact on the watch water resistance.
Should we wish to discuss how temperature impacts the watch performance, we should first find what's the material properties and characteristic of every components and variable at that given temperature. It is pretty much a gazillion different numbers unfortunately. Also because maybe a different manufacturer uses a different type of rubber (that might fail at a different temperature compared to another) you are at risk of ending in the rabbit hole.

FIY natural rubber normally fails around 85°C, I believe my heart will probably fail before my watch's gasket if I am to swim in those conditions.

3. If your question is related to the "jumping off a cliff scenario" you will slow down immediately loosing the vast majority of your speed on impact. Let's say you are jumping attached to a mini submarine, keeping a constant velocity of 16 m/s whilst diving, you can still dive down to 20M below the surface before having any issue. (I can't think of anything that goes that fast underwater by the way)

Don't forget total pressure is Static and Dynamic pressure combined

4. No, as we looked into question 1 a fluid will always seek to fill the area of lowest pressure regardless any "angle of attack". If a watch can sustain 3ATM of pressure, anything below that threshold is safe for a watch. Anything beyond will cause a failure. In fluid dynamics, pressure when channelled or constrained does vary. However due to friction will naturally tend to loose velocity. Should any engineer specialized in fluid dynamics disagree, please come forward and give us a deeper explanation 👍


Hoping this touched every point! Thank you so much for reading this thread

 

Great follow up, thank you!

 

My pleasure!! Those very actually some real solid questions!

Despite what many thinks, shows us that this is a subject that still has plenty of room for more discussions and clarifications!

Thank you for that.

 

Ho' Boy - here we go AGAIN with the whole "Static vs. Dynamic" argument...

 

Ho' Boy - here we go AGAIN with the whole "Static vs. Dynamic" argument...

I know old timer!

 

These are my favorite threads: knowledgeable people versus irrational WR-obsessed WIS on WUS

 

What can I say 🤣🤣
I have my irrational moments too you see... Like answering politely to some of the comments some of these people just made 😂😂👍

 

I’m not a WR fanatic but a 3ATM dive watch?

 

It certainly happened before:

Credit source:

Can I dive with a 30m WR watch? An empirical experience

We often see around the forum new topics asking questions like: "can I shower with my 8000m WR watch?" or "can I be at the pool with my 100m WR watch?" Unless these questions are a sort of preemptive excuse to get a new tuna (in which case I fully support it and would answer "no! Are you crazy...

www.watchuseek.com

Please understand that I am not saying this is or can replace a professional diving watch.
But can we dive with a 3ATM watch? There is no limit to what depth people can dive without training or qualifications, however 20 metres without it is already considered dangerous.
So for recreational diving, why not?


Vast majority of us out there still believe that a 5ATM watch can be used in water... for a short period of time? How can something like that make any sense?
And this is not just anyone saying it, what I believe are true watch enthusiast also struggle to grasp this concept nowadays still.

Not your case, but have you seen how many people believe we discussed this subject enough already? But have we? 😅😅

 

Disregarding ignorant/stupid claims (there are terraplanists, right?) it's well known no "dynamic pressure" will be anything near to be of concern. Neither is temperature, soap, steam, etc. for any normal wristwatch use case scenario (i.e.: one that won't kill the owner of the wrist the watch is attached to). In fact, 10m is a good enough pressure resistance as long as 10m means 10m (or 1atm for that matter).

The problem is not there. The problem is that... 30m doesn't mean 30m if the builder doesn't want to. That's the "benefit" ISO-2281 brought to the table: the ability to stamp on a watch a number the watch can't withstand.

Now, for the good news with an example: if the builder means the number it stamps on the watch, you are good with basically any number. This week I've been on holidays and the wristwatch that came with me was my faithful 2006 Omega Speedmaster Mk40: it's a 30m, pressure-fitted back and crown and chrono buttons. On top of daily showers (as always) it took two spa evenings including sauna sessions, and an hour of turkish bath (you know, cold and hot water, full steam, etc.). Result? no harm, ticking as always, today, +10s after a week.

Finally, it's true that any watch that sees water will eventually flood. Up to you risking flooding or risking letting it fall from your bedside table, forgetting it, losing it or being stolen when out of your wrist.

 

You can all the calculations you like to show this point but if you take a watch rated at roughly 100 fsw you are asking for trouble. That watch is fine for rain and storms and maybe a splash in the pool, but not much more. I have taken a Citizen windsurfing model rated to 10 BAR on a scuba diving trip with about 12 dives to 80 - 110 fsw and it filled up and died.

 

Sorry to read that your watch failed on you. Would you mind sharing more details with us?
Like how old the watch and when was last serviced before diving?

I personally consider Citizen a very reputable and excellent brand that make some great diving watches (like the Promasters series) which I have personally owned and taken to the water in many different occasions.
Calculations I'm afraid is what I always rely on. If a 10ATM watch survives the pressure tester for its rated pressure, and its taken 30 metre below the water surface (or 100 fsw), I'm afraid it's unequivocally and mathematically impossible it will fail (providing gaskets are healthy and assembled correctly)

Should you wish to put all these numbers aside, please refer to Seppia's excellent thread, where he personally conducted a very effective empirical test. Please find the link just above

 

I appreciate a mathematical approach to this, and find it interesting and somewhat persuasive.

One thing that I notice is missing from your equations is time. How does continuous time underwater fit into this equation? Is it projected that because a 3ATM watch is rated for the water pressure experienced while swimming, the duration of the water activity is irrelevant? What about water exposure beyond typical human capabilities (like 1000 continuous hours)?

 

This argument had no influence whatsoever as it is just as pertinent to any watch used in water. Divers or otherwise.


Sent from my iPhone using Tapatalk Pro

 

I don't think it should matter what activities a watch is rated to. If it is rated to 10 ATM, then it is rated to 10 ATM. No matter if the manufacturer recommends diving with it or not. I think this is a good explanation to me, who has sometimes wondered about what a 3 ATM watch can actually do. Now I know that a 3 ATM watch, can go down at least 20m even with dynamic pressure.

If a Citizen Windsurfing model is rated to 10 ATM, it doesnt matter if Citizen doesn't say you should dive with it, as they have already said it is rated to 10 ATM, so the watch will, unless Citizen has terrible quality control, survive 10 ATM of pressure and likely survive a 80m dive including any dynamic pressure.

Possibly windsurfing would put abnormal stress on the watch, however Citizen has certified it for Windsurfing AND 10 ATM, so it should be able to do windsurfing and still have 10 ATM WR.

 

Perhaps VinceWatch was referring more to mechanical stress and damages that could undermine wr?
But that could apply to any watch with any WR

What I wanted to say anyway is
Please bear in mind that dynamic pressure, once fully submerged in water, practically plays no role on our watches (as well as it doesn't when on the surface, for anything 3ATM rated and above according to our calculations)
As our movements speed once under the water will be extremely slow anyway.

If you are safe at 20M (when looking at the dynamic pressure effects) you will certainly be at 30M as well.
Without considering that with a minimum of 3ATM should be safe even on the surface for that matter.

 

But my watch has a screw down crown so that adds enough WR to compensate for the dynamic pressure derp derp.

 

😂😂

Well for anything that is beyond 10ATM a screwdown crown with a gasket will press that extra gasket on thread (normally a gasket is always fitted in the case's thread).
That's another very confusing subject for many.
Some screw down crown could have been designed without a gasket, in that case that feature adds no benefit to a watch water resistance.

Watch crown with tube gasket, and crown gasket chosen by us:

 

Why do you only care about dynamic pressure? Your calculations are looking at only momentary force and you fail to consider time within the pressurized environment. I suggest time at pressure is the critical component to a sealed vessel (i.e. a watch case).

My experience suggests that the number printed on a watch case regarding water resistance has little relationship with the watch’s actual water resistance capability.

In most cases, the number is either marketing (aka a lie) or simply the limit the company feels like testing the case to due to manufacturing time or evaluation cost (as seen with Seiko “air dive” models rated to 200m, yet have been independently tested to beyond 800m without issue).

Can a watch rated to 3 ATM be used while diving? Sure. It’s your money and your life, do what you want.

On the other hand I can buy a watch pressure tester rather to 6ATM for $150 on Amazon. If I cared about the watch, I’d just test it prior to diving with it.

 

Why do you only care about dynamic pressure? Your calculations are looking at only momentary force and you fail to consider time within the pressurized environment. I suggest time at pressure is the critical component to a sealed vessel (i.e. a watch case).

My experience suggests that the number printed on a watch case regarding water resistance has little relationship with the watch’s actual water resistance capability.

In most cases, the number is either marketing (aka a lie) or simply the limit the company feels like testing the case to due to manufacturing time or evaluation cost (as seen with Seiko “air dive” models rated to 200m, yet have been independently tested to beyond 800m without issue).

Can a watch rated to 3 ATM be used while diving? Sure. It’s your money and your life, do what you want.

On the other hand I can buy a watch pressure tester rather to 6ATM for $150 on Amazon. If I cared about the watch, I’d just test it prior to diving with it.

I'm afraid this is untrue.
The whole first paragraph looks in details at both the Static pressure generated at a hypothetical 30M depth, as well as how 3ATM equals in Pascal.

Only after looking at those, we interrogated the dynamic pressure data and run a comparison between the two.

Please feel free to consult each paragraph more accurately.

Giving the examples provided, I don't see how the time variable can play a factor.
Rubber only fails when looses elasticity (hence keep on top of maintenance)
Metal should last pretty much indefinitely, unless corrosion start to settle in.
However, if you have experienced some sort of failure due to time, please share these data here, and we'll see how we can add those variables in.

 

All I know when it comes to water resistance is that a round crystal does not always provide more water resistance than a non-round crystal — and, I am perfectly fine with that.

 

I think, on the subject of dynamic pressure, everything relevant was said by @lysanderxiii in his thread “Sigh, Myth Busting.... again” already in 2006, nevertheless I show a diagram, in which the change of the pressure with the necessary speed is represented.

To increase the pressure on a body at a constant water depth by only 1 bar / 14.5038 psi, a speed of 50 km/h / 31 mph / 27 kn must be reached.
If a diver should actually plow through the water at this speed at a depth of 30 m, then he certainly has other problems than the water resistance of his watch.


Of course, the water pressure acting on a body changes due to movement, but these dynamic pressure changes are so small in reality that they can be completely neglected.

 

I think, on the subject of dynamic pressure, everything relevant was said by @lysanderxiii in his thread “Sigh, Myth Busting.... again” already in 2006, nevertheless I show a diagram, in which the change of the pressure with the necessary speed is represented.
View attachment 17086972

To increase the pressure on a body at a constant water depth by only 1 bar / 14.5038 psi, a speed of 50 km/h / 31 mph / 27 kn must be reached.
If a diver should actually plow through the water at this speed at a depth of 30 m, then he certainly has other problems than the water resistance of his watch.


Of course, the water pressure acting on a body changes due to movement, but these dynamic pressure changes are so small in reality that they can be completely neglected.

The chart is correct.
Our calculations confirm that.

That's a very interesting post. My only constructive criticism is that we can still read from that thread, and I quote:

"you should never have a problem washing your hands, or showering, even with a 3 atm rated watch. A properly tested 10 atm rated watch should withstand anything water related"

When in fact if kept within its 3ATM/30M limit (when diving) a 3ATM watch can pretty much withstand almost anything water related already.

Plus there is a ton of info that yes is interesting, but that common sense can answer without making us loosing focus on the main topic
Nice thread anyway

 

Garmin states their Descent Mk2 watch is good for saturation diving and can be used for diving to 100m. It is rated to 100m.

On the other hand, I picked up a TAG-Heuer tourbillon that is rated to 100m, same as above. Unlike the Garmin the TAG is not a "dive" watch. This is my only watch that is not sold as a diver. I wrote TAG and they emailed me back stating the watch is not to be used for swimming and not to be worn in the shower. At another time I called their service center to ask about possibly doing a service on the watch as I bought it pre-owned. When I asked about swimming and showering the lady said you may be able to get it wet but under no circumstances should the watch ever be worn in the shower. WOW.

My conclusion was that watches should not be worn in the shower nor used to swim or dive unless they were sold for that purpose. When in doubt, regardless of the rating, try not to get it wet. You might be lucky or not.

ali

 

Wow, thats interesting. Was your TAG rated to 10 ATM or just 100m? I think 10 ATM is more specific whereas 100m could mean whatever TAG wants it to.

 

 

I wonder how a court case would end up if a watch rated on the dial to whatever failed at far less. While AD'S say one thing, and marketing says another, there is only one universal... The published tagged depth rating.

The argument of seal condition being moot as it is constant for all watches.

If we were to have trust in marketing over rated depths then I wouldn't take my Zodiac Super Sea Wolf diving as their marketing information states that 200m should not be taken scuba diving! 200m... really!


Sent from my iPhone using Tapatalk Pro

 

I originally posted this technical guide years ago on this very forum .

There is no such thing as too much water resistance.

Professional divers who make a living dwelling beneath the sea, performing salvage operations, repairing offshore rigs, and searching for sunken treasures rely on this very dive watch depth guide.

50 m = 150' = 5 atm Sitting by the pool and building sand castles, but watch out if the tide comes in.
100 m = 330' = 10 atm. Resistant to spray from sitting to close to Shamu at SeaWorld.
200 m = Washing your car or showering.
300 m = Swimming in the pool, but stay out of the deep end.
400 m = No watch is rated 400 meters because this depth does not physically exist. Depths go from 300 to 500. Engineers don't know why this happens.
500 m = 1,650' = 50 atm. Good for snorkeling.
1000 m = 3,300' = 100 atm. Finally, a REAL dive watch.
2,500 m = fancy pants desk divers only.

 

I originally posted this technical guide years ago on this very forum .

There is no such thing as too much water resistance.

Professional divers who make a living dwelling beneath the sea, performing salvage operations, repairing offshore rigs, and searching for sunken treasures rely on this very dive watch depth guide.

50 m = 150' = 5 atm Sitting by the pool and building sand castles, but watch out if the tide comes in.
100 m = 330' = 10 atm. Resistant to spray from sitting to close to Shamu at SeaWorld.
200 m = Washing your car or showering.
300 m = Swimming in the pool, but stay out of the deep end.
400 m = No watch is rated 400 meters because this depth does not physically exist. Depths go from 300 to 500. Engineers don't know why this happens.
500 m = 1,650' = 50 atm. Good for snorkeling.
1000 m = 3,300' = 100 atm. Finally, a REAL dive watch.
2,500 m = fancy pants desk divers only.

That chart is getting rhe m/atm equivalence wrong, but funny regardless.

 

I care more if the crown is screw down or not. I don't care what the WR or pressure rating is on a watch if the crown isn't screwed down.

 

Looking forward to hearing all your feedbacks.

First off, thanks for the post. I'd certainly rather read about and discuss some technical aspect of a watch's performance than read another "How long am I going to have to wait to get a Submariner?" thread

There have been several threads here over the years which discuss what I'll call "movement in water". They all seem to conclude that there's not much you can do at a depth of, say, 20m, which will significantly alter the pressures seen by your watch. You can only move your body so quickly in water so these effects seem to have a <= 2% contribution to your "effective static depth". Many watches are actually tested 25% beyond their stated depth in terms of pressure, so there should be no issues here.

The other category is one I'd call "movement into water". I don't believe your calculations have addressed this. From everything I've read this is a very complex thing to calculate and depends significantly on surface area and orientation. A professional cliff diver can hit the water a speed which would literally kill another person. The pro survives by orienting their body to minimize surface area of impact. If I get thrown off a jet ski at 50mph surely the size and design of the watch, as well as the orientation, come into play. For example, if the crown or crystal is on the leading edge of the watch hitting the water, it now receives the full force of that impact. But what if it were flipped 180 degrees? If the crown were on the trailing edge, it may well see a low pressure environment instead. I can't write out the equations for these things, but we all have experienced something along these lines. Smack your open palm as fast as you can into the water at a pool and it stings. Swim to the bottom of the deep end and open your palm, you don't feel a thing. This summer at the lake my brother jumped no more than 15' off a rock ledge into the lake. When he hit the water (quite ungracefully haha) he said it felt like he was in a car crash and it actually tore the plastic watch he was wearing off his wrist. Not 10 minutes later I mistakenly jumped off the boat with my phone in my pocket. I couldn't have gone more than 10' deep and I immediately climbed back out and into the boat. Pulling the phone from my pocket (one rated to withstand up to 30 minutes in 10' of water) it was already shut off with visible water drops behind the screen and camera lenses. Destroyed in 30 seconds. Anecdotal for sure. But the physics behind exactly what forces your watch sees at a 50mph water impact are surely not described by a single, simple formula.

 

First and foremost, thank you so much for taking your time and appreciating this thread Sir

Forgive me for saying it, but I think your thought process was bit all over the place.
The formulas for dynamic pressure we used are already accounting for the max pressure generated, given a known specific variable, like velocity (hence three different examples, including an impact at 50mph/80km/h that you have also mentioned) in a particular fluid with its specific density (in our case water).

Regardless you are at whichever angle impact you might be thinking of, or how long for (time does practically count for nothing) those results are looking at the maximum dynamic pressure generated, in the water, at that speed.
We could complicate our life endlessly by throwing in another million different variables, but please feel free to catch up on this brief Q&A and you will realize they don't change anything:

3ATM water resistance is a lot more than you have heard...

Hello guys, I have just put together a simple, but very detailed guide that explains, through some basic formulas and not subjective opinions, why 3ATM pressure is a lot more than we are lead to believe. Before going ahead please always follow and give priority to your watch manufacturer use...

www.watchuseek.com

But I will be adding a Q&A section at the top, as this questions have already been asked a few times here (angles, time, exposure etc) Cheers

 

Thank you for taking the time to explain the methods of testing in regards to water resistance. This is important information for those who are not sure of whether their watch may be fit for diving and for those who are looking for a dive watch and want more information so that they can make an intelligent choice when deciding to purchase one.

 

I can only say thank you for the kind words. The challenge wasn't so much understanding these case scenarios, but wording it concisely and effectively.
We often see there threads ending up with a million different formulas, and although I enjoy it as I am quite geeky, that do nothing but confusing the hell out of people!

Thanks again for appreciating my effort, I mean it.