There are fewer things more satisfying when wearing a watch than the click of the rotating bezel. For those of us with a bit of OCD, it’s critically important that your bezel always line up at 12. Just a small nudge of one notch means that we are rotating it back to where it belongs.
Why do Dive Watch Bezels Rotate in Only One Direction?
The title of first dive watch with a unidirectional bezel belongs to the Blancpain Fifty Fathoms, released in 1953. Just one year later, Rolex and Zodiac would both catch-up with releases of the Submariner and Sea Wolf respectively.
Vintage BlancpainFifty Fathoms
As a SCUBA diver, there are really three critical measures for a safe and successful dive: depth, time elapsed of your dive, and your remaining air supply. While one might just presume that it is possible to dive until your tank runs out of air, there is a secondary and no less important consideration: nitrogen.
When SCUBA diving, the air system delivers compressed air at the same pressure as the outside water. So as one dives deeper, and the water becomes denser, so does the air you breathe. Included in this dense air is nitrogen, which is stored within the body.
Most recreational SCUBA diving is timed so that when you ascend, this trapped nitrogen is able to be expelled as you ascend. For this process to work, however, it is critical that a diver not exceed the maximum time allowed for a given depth.
So as a diver prepares for their dive, they will note that if they are diving to 90 feet, then they can be at that depth no longer than 19 minutes without having to adjust their ascent back to the surface.
Before computers took over our lives, complex charts were used to plan dives. They are still used today as a safety backup, much in the same way as a dive watch.
Setting the Dive Bezel
It is with this in mind that the rotating bezel becomes very necessary. Rotating the bezel is done to set a particular time of reference. The most common approach for a diver would be to rotate their bezel so that the 12 o’clock marker signifies when it is time to exit the water.
A Rolex Submariner on ablue rubber Everest Bandwith its bezel rotated 19 minutes.
When the minute hand reaches the 12 o’clock pip, it is time to ascend.
A less common approach is to adjust the bezel so that the 12 o’clock pip lines up with the minute hand at the time the dive commences. The diver will then have to remember that they have to ascend when 19 minutes have elapsed.
A Unidirectional Bezel is for Safety
It is this timing procedure that brings us back to the one-way rotation of the bezel. During a dive, especially in tight quarters, it is certainly possible that the bezel may get bumped or twisted. Should that happen, a dive bezel will only move counterclockwise, which would shorten the dive. If the bezel would rotate the other direction, it is possible the dive would be inadvertently extended and create a dangerous situation.
A Note About Salt Water
While dive watches are meant to be enjoyed and are designed to endure the rigors of depth, salt water can be corrosive to steal and damaging to many of the seals and gaskets that protect the watch movement. Whenever your watch spends time in salt water, it is important to give it a thorough cleaning. Protecting your Rolex Dive watch with a rubber Everest Band is one more way to keep your investment safe while still enjoying your Submariner in its natural habitat - underwater.