Analogue Watches

Many sports watches have bezels and are used to measure elapsed time, but analogue watches used by divers should have a bezel that is easy to grip, even with cold, gloved hands. As divers must be able to monitor exact times to stay within safe diving limits, the bezel on a diver’s watch should also be unidirectional. A bezel that rotates only to the left will, if knocked, read a longer elapsed time, resulting in the diver surfacing early and remaining within safe limits. Second hands on analogue watches are also important as they indicate the watch is still working. A watch that stops while on a dive will give the potentially dangerous impression that less time has been spent underwater.

Luminous coatings either on the watch face or on the hands are important for reading information in low light. Tritium coating, which provides the brightest glow, was banned in Japan due to unacceptable levels of radioactivity, and was replaced with the safer Promethium, which is widely used today.