I followed a discussion online about the bezel on this old dive watch. People seemed to have difficult reading the bezel, which I can understand. It is not easy. So Andreas from Localtime gave a detailed explanation which I am sharing here with his permission.
The late 1960’s ‘Caribbean’ models were some of the first watches with a 1000m water-resistance and no-decompression bezels. Initially produced by Jenny SA (fun fact: current owner of Doxa Watches), they were also produced for several other companies, including Philip Watch, Aquadive, Ollech & Wajs, etc.
Here is how to read the Caribbean bezel, by dividing it into 4 zones or rings:
Zone A: indicates elapsed time (0 to 60 minutes)
Zone B: indicates depth in meters (21 to 60 meters)
Zone C: indicates bottom time (in 5-minute intervals)
Zone D: indicates safety stop time at 10ft (in minutes)
Let’s try this: Use zone B (inner ring) and take the 33m maximum depth position shown at 4h in yellow. Move outwards to zone C (second ring) and choose your bottom time between 20, 25, 30 or 35 minutes. Move outwards to zone D (outer ring) and match your bottom time with the number of minutes needed as a safety stop at 10ft (for example if your bottom time was 20 minutes, the safety stop must be 2 minutes, if your bottom time was 25 minutes, your safety stop must be 7 minutes, and so on).
I hope this helps. It will be documented on this blog for future reference.