Good evening everyone!

This column talks about mechanical watches from an engineer's point of view. This is the fifth in the series.

"Water resistance of watches"

I will be talking about this topic.

"Water" and "humidity" are nuisances for luxury watches, which are precision instruments.

Even getting a little wet can cause damage to your watch, so it's important to have the right knowledge to enjoy your watch. So today, we'd like to explain in detail about the water resistance of watches. We hope you'll take this opportunity to learn about the various types of water resistance!

Types of waterproof watches

This time, we will explain the water resistance of watches by dividing them into five major categories. Generally, dress watches tend to have low water resistance, while sports watches tend to have high water resistance.

Not waterproof

*Rolex "Cellini" from the 1970s

As the name suggests, this refers to a watch that is not waterproof. Although non-waterproof models are becoming less common among modern watches, they are still common among vintage watches, and even during everyday use, you must be careful of moisture from rain and sweat.

Even though Rolex has a strong image of waterproof watches, the Cellini collection from several decades ago is not waterproof.

There are some vintage watches that are waterproof, but if they have not been properly maintained by the manufacturer, they often no longer function as intended due to aging. As such, it is best to think of vintage watches as generally "not waterproof."

Water resistant to 3 ATM (water resistant for everyday use)

※A. Lange & Söhne "Lange 1"

A watch with 3 ATM water resistance can withstand water pressure up to 30m deep when stationary. It is also called "waterproof for everyday use" and is used in a variety of watches regardless of price range. Since it has a minimum level of water resistance, it can withstand rain or splashes of water when washing your hands, but you cannot directly immerse the watch in water, such as washing dishes while wearing it or wearing it in a pool.

It is also still fresh in our memory that in 2024, Patek Philippe unified the water resistance of its representative models such as the Nautilus and Aquanaut to 30m (3 atmospheres). Below is a quote from Patek Philippe's press release.

" It provides clear, easy-to-understand information about the everyday activities you will perform while wearing the watch, including hand-washing, showering, bathing, swimming and other underwater activities, and diving up to 30 meters, which closely matches real-world usage."

When we interpret this, it is not that the waterproof performance of the Nautilus and other watches has been reduced, but rather that the waterproof labeling, which was previously difficult to understand, has been changed based on actual usage conditions, and it seems safe to assume that the watch now has a fairly high level of waterproof performance, capable of withstanding diving up to 30m.

Water resistant to 10 ATM (enhanced water resistance for everyday use)

*Grand Seiko "SLGH005"

Watches with 10 bar water resistance are also known as "enhanced water resistance for everyday life," and are suitable for not only working while wearing clothes, but also for marine sports such as yachting.

* [Rolex][Rolex] "Submariner Date" "Ref. 126610LN"

Wristwatches that are waterproof for air diving are called "diver's watches," and due to their design, many people choose them as fashion items. Nowadays, they look natural when paired with a suit, and their ruggedness creates a sophisticated impression, which is why they are extremely popular.

Waterproof for saturation diving

* [Omega] "Seamaster Planet Ocean Ultra Deep" "Ref. 215.30.46.21.03.001"

Saturation diving watches have the highest level of water resistance and can withstand diving to depths of over 1,000m , and are also known as "class 2 diving watches (waterproof for saturation diving)." Many of these watches also have other features that are useful for diving, such as a unidirectional rotating bezel and a helium escape valve.

Recently, models such as Omega's Seamaster Planet Ocean Ultra Deep have been released that are water resistant to 6,000m but do not have a helium escape valve, and this too shows the advancement of technology.

* [Rolex] "Sea-Dweller Deep Sea"

If you think about how many people in the world actually do saturation diving, this watch is overkill for most people, but many people choose it because of the sense of security it gives you with its overwhelming functionality, as well as the thick case and helium escape valve, which appeal to men.

Be careful about getting it in water

The biggest cause of waterproof watches breaking down is overconfidence in their function.

"It's waterproof up to 100m, so you can wash the watch with water."
"It's a diver's watch, so it's okay to jump into the pool."

Many people may think this way, but in fact, just because a watch is waterproof does not mean that it will be fine if you don't dive to a certain depth. If the water pressure exceeds the specifications, water will get in, and if you do not close the crown properly, the watch will not function properly as it should.

Some people may have noticed that their watch has become cloudy after washing it with water, but the cause of this is the force of the water coming out of the tap. A watch that is water resistant to 100m can withstand the water pressure that occurs when you slowly dive to 100m, but the water pressure from a powerful tap can exceed that. Even if you think, "I just washed it with water...", you may be unknowingly applying pressure that exceeds the watch's specifications.

The cloudiness of the watch is evidence that water has entered the mechanism, and in this case an overhaul is necessary. In order to keep your watch in good condition for a long time, it is extremely important to "prevent moisture from entering the watch."

Tightly close the screw-down crown, valve, etc.
Periodic overhaul and replace consumable parts such as gaskets
Handle with care

Please be aware of this and handle it accordingly.

summary

There are many different types of waterproof watches, and as you can see, even if a watch is labeled as waterproof to 30m, the actual waterproof performance can vary greatly depending on the manufacturer. Make sure that the watch you are looking for has the waterproof capabilities that suit your intended use before purchasing it.

Also, if you are considering watches as a hobby, we recommend that you acquire basic knowledge about their functions, not just their waterproof performance.

We hope that this article has been useful to you and has piqued your interest in luxury watches! If you have any questions, please feel free to ask us directly, and we look forward to hearing from you!

Look forward to the next one! See you next time!

機械式時計徹底解剖