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I've been wondering when dive watches made the change from bidirectional smooth to unidirectional click-type rotational movement. Most vintage dive watches I've come across have biredctional, smooth rotating bezels. For example, I own a 1969 Bulova Snorkel Oceanographer and 1975 Caravelle 666 foot dive watch. Both bezels move clockwise and counter clockwise.

Perhaps this was more a function of individual manufacturers, with higher end dive watches like Rolex and Omega having unidirectional from their beginning.

I think most manufacturers realized at some point that there is greater potential for error in a bi-directional bezel that turns smoothly if it were to snag on a wetsuit . This could of course be a hazard to divers watching their dive time.

Anyone know when the transition to unidirectional bezels was made in most dive watches?


Zenith Forum Co-moderator
18,031 Posts
I'm not sure when this officially came into use (or should I say: law). Certainly, not all watches looking like diver's watches are really diver's watches! The cheap vintage ones with pin lever movements just wanted to give you that certain feeling and never made too much pretence about being a true dive watch.....

In Germany, the definition of a diver's watch is governed by the DIN (Deutsche Industrienorm) 8306. This specifies, among other things:

1. Waterproofing to at least 20 atmospheres
2. Screw down crown
3. Luminous markers and hands
4. Marker at 12.00 differs from the other markers
5. Unidirectional rotating bezel, rotating counterclockwise, 60 ratchets
6. Luminous dot on bezel at 12:00
7. Markings on bezel spaced at 5 units (minutes or seconds, whichever way you look at it) apart, for the first 15 units at one marker every unit
8. Flank protection on the crown

...and probably some more (helium valve on the professional jobbies for a start). The reason for the unidirectional counterclockwise bezel is, of course, the this is used to time the period under water so that an accidental shift of the bezel will "extend" the time already spent under water so that you are left with an excess of air rather than too little!

Hartmut Richter
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