The Rotating Dive Watch Bezel
The Rotating Dive Watch Bezel
Just like the chronograph and its tachymeter originally designed as a tool for car racing drivers, you should know how a dive watch bezel works regardless if you’re a scuba diver or not. You’d be surprised how useful a dive watch bezel can be in everyday terrestrial life…
Dive Watch Bezel: History & Function
Necessity being the mother of invention, the rotating dive watch bezel was introduced by Rolex and Blancpain in the early 1950’s to track a diver’s bottom time, or time spent underwater. Oxygen being limited, the bezel can act as a reminder to prevent divers from exceeding their diving time limit.
Dive Watch Bezel Types
The rotating dive watch bezel, scaled or not, is mainly divided into 60 minutes or 12 hours and has a luminescent zero marker, often a tiny circle or triangle.
Bidirectional vs. Unidirectional Rotating Bezel
While the first rotating bezels produced at the beginning of the 1950’s for dive watches were bidirectional, Blancpain presented the first unidirectional bezel on its iconic Fifty Fathoms diver in 1954.
Since the unidirectional bezel rotates counter-clockwise, it’s actually a safer way to track bottom time. If the bezel is accidentally moved underwater it would only shorten remaining dive time instead of lengthening it.
External vs. Internal Bezel
There are 2 types of dive watch bezels: the more popular external one and an internal version introduced afterwards.
While the external bezel is fixed on top of a watch, the internal one is installed under the watch glass and is operated by an additional crown (on a super compressor for example). Even if the internal version is protected from unexpected movement, it’s harder to manipulate than an external bezel with indented grip….with or without diving gloves.
The deeper you dive, the less visibility one has. Not a problem for divers with a bezel lined with luminescent minute markers. Even those with only a luminescent dot on the zero marker will be able to accurately track time.
Tracking Elapsed Time
To start simply turn the bezel to align the zero marker with the minute hand. As time goes by, the minute hand will continue moving. If it points to 20 on the bezel’s scale, this means you have been diving for 20 minutes. Piece of cake right?
Tracking Remaining Time
A bit of math is required here. If a diver has a bottom time limit of 25 minutes, you must first subtract this number from 60 minutes to get…yes, the remaining time. 60 – 25 = 35. Turn the bezel so that the 35 mark on the scale is set against the minute hand. It will take exactly 25 minutes for the minute hand to reach the zero marker.
For those who aren’t professional divers, don’t worry you’re still in the right place. The dive watch bezel comes in very handy whenever you need to track elapsed or remaining time.
Do you prefer linguine al dente rather than soft mush? No more than 8 minutes then. Are you a stickler for perfectly infused Ceylan tea? Better time it for 3-4 minutes. Are you parked in a 30-minute drop-off/pick-up only zone? How convenient, you’ve got on your diver today…