Why Do Dive Watches Have Rotating Bezels?

Every watch has a bezel. Some bezels are stationary and some bezels can rotate.

In this blog post we’ll learn what a rotating bezel is, and why do dive watches have rotating bezels. We’ll also learn how to use a rotating bezel on a dive watch as well.

Plus we’ll even give you a little history lesson on dive watches and their bezels.

What is a rotating bezel?

First, a bezel is the ring around the dial that keeps your watch crystal secure and attached to your watch’s case.

A rotating bezel is a bezel that you can twist around. It can either be unidirectional (only moves in one direction), or bidirectional (moves in both directions).

Today, most rotating bezels are unidirectional so as to stop minutes being accidentally deducted.

Rotating bezels can be found on dive watches. As they have a special use for diver’s on their scuba dives.

The rotating bezels on dive watches will often have grooves to make it easier to grip and turn.

A dive watch is a watch built to handle high levels of water pressure. Therefore they come with high levels of water resistance. Learn more about them here.

Why do dive watches have rotating bezels?

Dive watches have rotating bezels so that divers can measure how long they have spent underwater. This calculation will help them keep track of the amount of oxygen they have left for their dive.

Keeping track of the length of time of a dive is essential to performing a safe dive.

If you’re a scuba diver you’ll know about the bottom time. For all the non-divers reading this, the simple definition of bottom time is; the total time spent from the start of your descent to the start of your ascent. 

A diver can use the rotating bezel of their dive watch to help them calculate the bottom time. 

Divers need to watch their bottom time very carefully, as they are often going to deep depths on a scuba dive. So if they aren’t precise with their timing then they risk serious injuries.

How to use a rotating bezel on a dive watch

Using a rotating bezel to measure time on a dive watch can be done in two ways:

  1. Count Up method (easy)
  2. Count Down method (need to do some math)

Count Up method

The Count Up method is the easiest way to use a rotating bezel to measure time. All you do is align the 12 o’clock bezel mark with the minute hand. Then you can see how much time passes from that point.

Animated GIF - Find & Share on GIPHY

Count Down method

The Count Down method is more difficult, but this the safest, and most traditional, way to use a rotating bezel to measure time spent on a dive. For this method you:

  1. First calculate what time you will be measuring.
  2. Then you will take that time and take it away from 60 minutes.

E.g. 60 minutes – 40 minutes = 20 minutes

  1. You are left with a time; e.g. 20 mins. Then you need to align that time with your minute hand on your dive watch.

E.g. If it’s 20 minutes, then align it with the 20 minute marker on your bezel.

  1. Your dive watch will then count down to where you placed the marker. In the case of our example it will count down for 40 minutes.

But say if you don’t dive with your dive watch. Well then you can simply use the rotating bezel on your watch as a handy timer.

For timing things like your dinner or even a workout.

Brief history of dive watches and their rotating bezels

The Rolex Submariner was one of the world’s first modern dive watches. It came with a rotating bezel too. Rolex released their first Submariner in 1953. Now the Sub is probably the world’s most famous dive watch.

Learn about the history of the Rolex Submariner here.

First Rolex Submariner

However, Blancpain released their modern dive watch just before Rolex in 1953. Their Fifty Fathoms diver is considered by many to be the world’s very first modern dive watch.

Both the Submariner and Fifty Fathom featured a rotating bezel along with high levels of water resistance for the time.

The Blancpain Fifty Fathom diver was even the first dive watch to feature a unidirectional rotating bezel. The standard bezel of today’s divers.

If you want to learn the history of the Blancpain Fifty Fathom then check out this great documentary.

But before the 1950s there were many other water resistant watches that were invented and released before the first modern divers.

However, none of them featured a rotating bezel until the Blancpain diver of 1953.

The Rolex Oyster is heralded as the world’s first “waterproof” watch. This watch shot to fame when it was worn by Mercedes Gleitze in 1927. She was the first woman to swim the Channel. 

She wore a Rolex Oyster for her 10 hour swim. After she completed it, the Rolex was still keeping perfect time.

The Rolex Oyster had a screw down crown and a screw in caseback. Both of these features are used still today in modern dive watches. 

As history has marched on, the dive watch with its rotating bezel has had more and more features added to it. 

Check out our guide to dive watches, and discover what other features make up a dive watch.

Learn More

Want to find out more about how watches work. Then check out our guides, as we try to answer all the main questions surrounding watches.

Discover more here.