What does “Water Resistant” really mean?
Water resistance of watches is rated based on a laboratory pressure tests comparable to a swimmer or diver sitting still at that pressure level. But people hardly sit still when doing water based activities, which makes its water resistance different when in the real world.
The water resistance rating is flawed. For example, it doesn’t take into account:
- Sudden, rapid, and repeated water pressure changes experienced by the wrist of a surface swimmer. The force of plunging your arm into the water while swimming can for a fraction of a second greatly exceed the static pressures the watch was rated for.
- High water temperatures experienced in a hot tub. Normal diving and water activities are done in temperate to very cold waters–not water exceeding body temperature. Such high temperatures can damage the water protection seals of a watch.
- Sudden changes of temperature experienced going from a hot tub to a cold swimming pool. In diving and swimming, temperature changes are usually fairly gradual. A sudden transition from the 100º F of a hot tub to the 70º F of a cold pool causes a contraction of the rubber seals in a watch–which may allow water to leak in.
- The ability of the watch to STAY water resistant as it ages. The seals that prevent water from entering the watch will weaken and fail with age. For use in water, water resistant watches should be pressure checked every year. The seals should be replaced at least every two or three years.
- Showering or bathing with your watch on can be bad for it, due to hot water issues, and the fact that soap is a fine level abrasive. Soap can build up in the small, precision joints of the watch bracelet links. Over time this can wear down the link joints, ruining the bracelet. This is a greater issue with softer metals, such as gold. But steel can also be worn down this way too.
Why aren’t watches “Waterproof” anymore?
The term “waterproof” was discontinued starting in the late 1960’s. Here’s why.
Several government organizations, including the Federal Trade Commission in the USA, investigated the truthfulness and accuracy of product labeling and advertising. “Waterproof” was considered to have misrepresented the products as more capable of preventing the entry of water under normal use circumstances than they were actually capable of. Specifically, diving-type watches never have been completely ‘proof’ of water entry under normal use and within the stated depth ratings. The seals that keep water out are not completely impervious and their effectiveness can be reduced over time with age, deterioration, and exposure to chemicals.
The term “water resistant” is now used to describe such watches. There are no technical differences between a waterproof watch and a water resistant watch–they use the exact same methods and technologies to keep water out. The difference is only in what term was considered appropriate to describe it at the time it was made.
What does a Helium Relief Valve really do?
This is a common, confusing question, because most people don’t use or don’t know how to use it. And with good reason. Unless you’re involved with a multimillion dollar deep-sea exploration project, the helium relief valve won’t really do anything for you.
No, really. It’s not even used with any normal underwater diving or SCUBA diving activity. It has nothing to do with the depth rating for a diving watch, and helium does NOT seep into the watch while the watch is in water at any depth.
SCUBA diving activities normally occur at depths of no more than 120 feet. At 250 feet, air becomes toxic due to changes caused by the high pressures at such depths. For those who do very deep sea research, they often use diving bells, dry dive suits, and other types of very deep ocean exploration vessels. In some of these, a highly helium-saturated atmosphere is used to avoid the air toxicity effect.
The purpose of a helium release valve is for people who wear their watch inside the helium-saturated environment for an extended period. Because helium is the smallest atom, it will seep through the watch’s seals under the high air (not water) pressures in this environment. If the watch stays in this environment for an extended time, helium will continue to seep in to the watch until the air pressure inside the watch (initially surface air pressure) equalizes to the air pressure in the environment.
This becomes a problem when the vessel is brought back up and depressurized. The helium which seeped into the watch over a couple of days, cannot seep out any faster. The excess pressure inside the watch needs a way to release faster than it seeped in. It is only in this situation that a watch needs a helium relief valve at all. If a relief valve was not on the watch, the excess pressure would likely escape by pushing the crystal out.
That’s why the helium release value is useless to most people, because most people rarely find themselves in the situation described above, and therefore, have no need to release helium. So why do watches include it? Because it’s an interesting feature that makes the watch more exotic. An fun feature to have, but you’ll likely never need it.
However, there is one thing you should remember in regards to this valve: never leave it open. It serves no purpose and increases the risk of damage, though it’s designed to still be water resistant with the valve open.
Is a diver’s watch suitable for all water activities?
No. Just because it is a divers watch, you should not assume that it is suitable for all water activities.
Most manufacturers and authorized dealers only provide a depth rating without explaining much else, leaving consumers to assume that it is okay for all water-related activities, as long as they don’t exceed that depth rating.
That being said, your divers watch is likely still a great quality watch and will last for years. You should just take the effort to find out the limitations of your specific watch so you don’t accidentally harm it.
Each watch is different, but here are two general tips that apply to all divers watches:
- Make sure the crown and helium relief valve is properly screwed down, so as not to comprise the water resistance in any way.
- Do not use the chronograph buttons under water. They are not designed for that, and could allow water to run in. There are some watches have that capability, but as a general rule, avoid it.
Can I use an older/vintage waterproof or water-resistant watch for diving or other water activities?
Water-resistant seals are not permanent, and the quality deteriorates with age, so an old waterproof or water-resistant watch is probably no longer waterproof or water-resistant. We recommend sending us any water-resistant watch, especially older ones, once a year to check, maintain, or replace its water-resistant seals. We can recondition an older water-resistant watch and install new seals, and test it to make sure it’s functioning properly.
And when diving, using old or outdated equipment could put your life at risk. Professional divers would never do it, and neither should you. You’re better off assuming an old watch is no longer water resistant, and only wear it when there’s not a risk of damaging it, or worse, endangering yourself.