iwc 3769 Mode D'emploi page 28

Marking the start of a dive
The triangle on the rotating bezel can be aligned with
the minute hand by turning the rotating bezel anticlock-
wise. The desired point in time (e. g. the time of entering
the water at the start of the dive) can be set in this way.
You can read off the elapsed time (e. g. the duration
of the dive) on the rotating bezel. For safety reasons, the
rotating bezel can only be rotated in an anticlockwise
direction. The rotating bezel is indexed audibly and per-
ceptibly in steps of one minute, and it is also legible in
the dark thanks to the luminescent markings.
If you are planning to use the watch to time dives,
you should have certification as an open water
diver and have the water-resistance of your watch
checked regularly by an IWC service centre.
Cleaning the watch after diving
After diving – and especially after diving in seawater –
you should rinse your watch under running mains water.
This will prevent salt incrustation on the case, bracelet
and clasp.