Water Resistant Watches

Water Resistant Watches
by John Allen

The degree of water resistance needed in a watch depends entirely on how it’s going to be used. If it won’t be immersed to any appreciable depth, then minimal is fine, but if you’re considering it for swimming or diving, then something more substantial is required.

Depth ratings for the amount of water-resistance vary from about 30 meters (100 feet) to 1000 meters (3300 feet) and more. The point to remember about them is that the rating determination is done under controlled conditions in a test lab and rarely reflects the real world. For instance, in a lab, the watch isn’t being moved or bumped, nor is the water temperature varied.

Generally speaking, a depth rating of less than 100 meters (330’) means the watch can be worn in the rain, or will be okay if splashed. Ratings greater than 100 but less than 200 meters (660’) mean the watch can be used swimming or for shallow dives, like snorkeling. For scuba diving you need a rating of 200 meters or greater.

Obviously for deep diving, including everything from technical to commercial or saturation diving, the depth rating should be at the high end and preferably to an appropriate ISO Standard.

Manufacturers make watches water resistant to varying degrees through application of sealants inside the case; use of o-rings and gaskets of rubber or some synthetic material to seal all joints; extra-thick crystals; extraordinary precision of machined parts; gas filling; pressure venting; and various other methods.

Many of these features aren’t easily discernable, however a couple are easy enough to observe visually. First is a case-back that screws down into the case against a rubber or synthetic seal. Look for notches around the case-back that are the leverage points for the jewelers tool used for this purpose. Secondly, the crown should screw in against a similar seal, thus locking down the stem.

Another factor is the case material. For diving, it should be stainless steel or titanium. Some polymer cases will work if rated to an appropriate depth. Other materials including gold don’t work well because they aren’t rigid enough to withstand pressure at depth. Just a slight flexing can allow water to seep in around a seal.

Finding a watch that can just get wet is easy enough, but finding one that can survive the rigors of scuba diving requires more scrutiny. As mentioned above there are several features that contribute to maintaining the water-tight integrity of a watch, many of which aren’t so observable.

The best way to be certain, after visual observation, and a review of the manufacturers specs, is to choose one with a sufficient depth rating. If recreational scuba diving is the intended use, then it’s reasonable to infer that a watch with the deeper depth rating of 200 meters (660 feet) or more will meet your needs.

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