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As the title of Part 3 of the Watchmaking Academy suggests, this is a very delicate subject. Everyone expects something different from a watch and often has no idea how to find their way in the confusion of bars and atmospheres. On the other hand, the more experienced ones may find office diving, which is enjoyed by land-based owners of diving watches, to be laughable. Why? You will find out in the article, where we will discuss the water resistance of the watch from all possible points of view. The length of the text will probably be enough for you until the holidays, when thanks to it you can immediately take the watch to the water without any worries.
We'll stop at the 2 waterproofing standards, talk about where you'll use them, and also the fact that, unfortunately, it's not done in a way that you might think of right away. We'll talk about what kind of testing the watch goes through, how it's protected against water, and what you definitely shouldn't do with a waterproof watch. And finally, we'll debunk the myth of dynamic pressure that supposedly can break a watch's water resistance while swimming, and recommend which watches will be like fish in water.
There are 2 types of water resistance markings on watches (for brands that recognize the International Organization for Standardization ISO system), which can be confusing even for owners who read the manuals and are interested in their watch treasure. Fortunately, you can recognize both designations by looking at the dial or pumpkin.
The first type refers to ordinary mortals who introduce the watch to water during recreation or recreational water sports. This "ordinary" designation refers only to the water resistance in question and is a "Water Resist" designation of 30M, 50M, 100M, or up to 200M.
In contrast, certified diving watches follow different rules and the designation includes many other tests besides water resistance. Such a watch will have a “Diver’s” mark in front of the depth value to which you can dive with it. The Diver's designation itself is considered a full-fledged alternative to the ISO 6425 compliant designation.
The standard designation of water resistance (Water Resistant) is based on the depth at which a one-day watch test took place. The watch is in a tank where it has to withstand the given water pressure all day long. Although it is a simulation, it is long enough to reveal all the leaks.
What is a small catch for users is that only samples of watches from the series and completely new watches are tested in this way. But you can fully rely on this common certification, provided you know how moisture can get into the watch, which we'll explain in a moment.
Jsou-li hodinky označeny například DIVER’S 200M, jsou certifikované podle ISO 6425, která určuje, že každé takto označené hodinky prošly testováním. Označení v atmosférách snadno převedete na metry vynásobením 10. Tedy např. 10 ATM = 100M. Potápěčské hodinky mají obvykle vyšší cenu, ale ani to nemusí být pravidlem (viz například Seiko, Citizen, Victorinox). V ceně se odráží hlavně testování každého kusu, ale také to, že certifikace zahrnuje mnohem víc testů, které zajišťují bezpečnost potápěče.
For example, if a watch is marked DIVER’S 200M, it is certified to ISO 6425, which specifies that every watch marked with this has passed testing. You can easily convert the designation in atmospheres to meters by multiplying by 10. So, for example, 10 ATM = 100M. Dive watches usually have a higher price, but this may not be the rule either (see for example Seiko, Citizen, Victorinox). The price mainly reflects the testing of each piece, but also the fact that the certification includes many more tests that ensure the safety of the diver.
Manufacturers use several types of seals and rings in places where water has a chance to penetrate the watch. Whether it concerns the diving ones or the ordinary ones, these are the places:
Instead of the lens and bezel touching, which is what the lens seal solves - it's a permanent seal that doesn't require service. For the user, this means that the gasket must be replaced when the slide is replaced. The investment is minimal, but its impact is priceless.
Furthermore, water can penetrate through the crown and crown, which are also equipped with an O-ring, and the same service replacement principle applies here as for the glass. In addition, it is a good idea to replace the seal every 2-3 years (read the manufacturer's recommendations and also take into account whether you often take the watch into the water).
As for the pumpkin, the O-ring fits into a groove (diving) or a profile (regular). In diving watches, the gasket fills the groove completely when closed, even when closed with normal force, because the gasket is always slightly larger in volume than the groove. Therefore, the moment the gourd touches the case, you are sealed and any further tightening will not increase the water resistance.
When servicing a diver's watch, the recommendation to replace the seal applies doubly, with all the consequences. Especially since the factory testing was done on a new, unworn and unopened watch. The watch has not been exposed to corrosion, salt or warm water.
And if you think that warm water only refers to a hot shower, then you're wrong - it's also a hot tub or a sauna, where some people really take their watches. However, we definitely cannot recommend this, because the heat prepares the path of moisture quite effectively. So even though both certifications include tests under certain temperature fluctuations, it is definitely not a simulation of this relaxing activity, and believe me, your watch will not really relax in a hot tub, on the contrary - it can very easily get damaged.
The crown passes through a large opening through the case, where again air, water and moisture can penetrate to the movement. The crown therefore has an additional ring seal at its base that abuts the case.
For diving watches, the declared water resistance is ensured when the crown is screwed in. It sometimes happens during dives that you forget to screw in or push the crown. Divers should not panic, just like during a dive, because even in such a case, the watch should theoretically (!) be protected by a seal (as we explained above - the seal and its storage are precisely dimensioned for divers).
The stumbling block occurs when you start screwing the crown in water, because the moving seal simply doesn't leak. So it is better not to turn the crown in the water and suffer the omission until it emerges. But take this only as advice for the ultimate emergency, when you accidentally forget the crown. It is still true that a unscrewed crown has absolutely nothing to do in water.
You may be correct in thinking that any time the watch is opened, the watch is at the mercy of both the watchmaker and the temperature and humidity in which he is working with the watch. If the watch is disassembled at an authorized service center, it should also be a guarantee of a relatively dry environment. However, if the battery is replaced or serviced in an uncontrolled environment, moisture condensation may occur later. In our geographical location, this is not such a risk, but it is a phenomenon that is closely related to how and especially under what conditions you handle the watch. So consider getting your watch serviced on vacation, where your watchmaker isn't around, but it's hot and humid.
If it is a watch with water resistance up to 200M in the standard design (ie WR as Water Resistant and not DIVER'S 200M), of course its case also has a seal, which is no different from the diving one. But the difference is that it is stored in a simple profile and not in a precisely turned groove.
As for the crown seal on the standard water resistance, the ring seal is not on the crown body, but is attached in the case (not expected to be replaced that often). However, the same principle applies here as for divers – handle the crown only in a dry environment and at normal atmospheric pressure and temperature to prevent moisture from entering the watch. That's all it takes to keep your watch water resistant.
You can also meet a pumpkin that is screwed on. In that case, it fits very tightly and evenly to the housing thanks to 4-8 screws. The seal is exactly the same as for a pumpkin without screws. But even this system is not without risk. Care must be taken when returning the pumpkin - individually added screws can exert uneven pressure on the gasket, where it is extremely overloaded at the points of contact.
In the case of normal water resistance, it doesn't matter so much and the watch should be ok. If you have a screw cap on a diving watch - again, it is only recommended to replace the seals regularly after about 2 years if you dive with the watch. If you have a clear case on your watch with a screw-on case, this is another place where you need to protect your watch from moisture. But don't worry, real grebes fortunately don't have transparent pumpkins.
Prescription glasses owners are probably in the clear because they know well when their glasses fog up out of nowhere - when going from a cold to a warm (and even worse humid) environment. This is exactly how a problem can really arise with the penetration of moisture into the watch. The moment you handle the crown, for example, after a violent summer storm, or on vacation, when you step out of the air-conditioned space into a steamy and warm environment, you are in for a problem. Moisture will seep in when the seal is handled through the points described above and can condense in minutes. The described situation affects any watch, regardless of whether it is a diver's watch or one with an ordinary certification.
A simple experiment will confirm that condensation is everywhere, where you place ice on the glass of a (closed) watch for approximately one minute, so that the glass cools down significantly. The air inside the watch, even if it is relatively dry, also cools down and thus fog appears on the glass, as even this tiny amount of moisture is precipitated. After the temperature has re-equilibrated, the condensed moisture should dissipate again.
Your watch may fog up and this may be normal. Just wait for the watch to warm up on your wrist. In this case, there is definitely no damage and all waterproofing is fully preserved. You can tell that it is not excess and unwanted moisture by the fact that it typically appears in the middle of the slide. This is because it is the place farthest from the metal surfaces that conduct heat well, and where the conditions are most easily equalized. You can also tell that this is a normal phenomenon by the fact that droplets do not appear in the fogging area.
Before the arrival of this certification, it was simply a time of uncertainty. As you can imagine, the "risk is reward" approach did not pay off very well, because in the period before the release of the revised version of ISO 22810 in 2010 (international standard ISO 22810 Horology - Water Resistant Watches), manufacturers issued recommendations such as: "you can shower with the watch, but we do not recommend swimming". Well, look for a real-life situation in such a recommendation. Weaker natures probably took off their waterproof watches even when washing their hands...
However, since this standard is currently used for the vast majority of watches, we will summarize its form. More detailed and verified information on Water Resistant Mark certifications can be found, for example, on Wikipedia.
In the Helveti offer, you can also find watches with higher water resistance, which were created, for example, in honor of the first dives in the North Sea. They are, for example, the Edox Skydiver Neptunian or CO-1, the Tissot Seastar, the Traser Diver Automatic or the SuperSub with an ordinary WR but with a great price tag, or extraordinary chronometers with the WR 1000M Ball Engineer Hydrocarbon.
The water resistance test according to the mentioned standards takes place in simulated conditions, which brings some pros and cons.
The conditions for testing divers are much more demanding:
A diving watch must have a device for measuring time, which is most often the bezel, which must also meet certain characteristics regarding the indexes. The bezel is unidirectional so that the measured time is not accidentally extended when diving. As for lighting and luminescence, you need to be able to tell the time in the dark and adjust the bezel.
What you can learn on the Internet:
When swimming, when the movement of the hand in the water creates dynamic pressure on the watch, it creates conditions that exceed the limits of the given water resistance certification.
In other words, it is supposed to explain the fact that water enters the watch intended for swimming due to the increased pressure that occurs when the water is broken by the hand. We'll have to do some math, but the result will reward you with the fact that the pressure of swimming won't break your watch's water resistance in the slightest, even when using an underwater scooter that reaches speeds of around 4km/h and takes you 20m below the surface.
We will not strain you too much with the calculations, you can look at them in the picture. If we use Bernoulli's equation, which is used to describe fluid mechanics, and calculate the static pressure of the water acting on the watch at 100 m, we get a result of 980,000 Pa.
If we use the equation to calculate the dynamic pressure and include the swimmer's speed of 3 m/sec (10.8 km per hour), then even if it were such a superhuman performance, the movement of the hand to the static pressure for which the watch is prepared would added only 450 Pa extra, which is equivalent to the pressure exerted by 4.4 cm of water.
You can guess for yourself what this means for the water resistance of the watch when swimming. Even if you're a very good swimmer and you'll be flailing your arms like crazy, it won't be an extra burden on your 100m water resistant watch.
To put it another way, let's say you're swimming 25m underwater and your watch is only water-resistant to 50m. Then you'd have to swim at 80km/h to break it's water resistance at half that depth. This means that the dynamic pressure has absolutely negligible effect on the water resistance of the watch while swimming (and that you should not stick your hand with the watch out of the submarine).
We hope that now you won't be afraid to take your watch to the seaside on holiday, and based on the information provided here, you will fully enjoy both. If there's anything else you're interested in, or have your own experience with watches in the water, let us know in the comments. We will look forward to the water, especially the watch!
EUR
