Question for the diving experts.

[foghorn]

After nearly a year of ownership I just noticed that , on the bezel of my Zodiac SeaWolf reissue, there are triangles instead of lines at the 3,6 and 12 minute marks.







I know that on vintage style chronos this is done on the minute subdial (one theory is for timing pay phone calls) but I'm wondering what the significance it is on a dive watch bezel. I know it's a vintage holdover but I want to know why. I got bored looking on line so I figured I'd reach out here to our many intelligent afficionados of such minutiae.

[relaxer7]

Extra warning for when you're oxygen is reeeaaallly gonna run out and you're about to turn blue and float up to the surface of your bath?

[bobbee]

Beware of spudsharks! (Like relaxer7's Bananacuda!)

[Racer-X]

“The markers for 3, 6, 9 and (especially) 12 o'clock on the watch face and the zero marker on the bezel of analogue diver's watches are usually conspicuously styled to prevent disorientation induced read out errors.“

https://en.wikipedia.org/wiki/Diving_watch#Legibility

[iwasbanned]

Irrelavent, that watch is not ISO certified and as such would kill you during a dive.

[foghorn]

“The markers for 3, 6, 9 and (especially) 12 o'clock on the watch face and the zero marker on the bezel of analogue diver's watches are usually conspicuously styled to prevent disorientation induced read out errors.“

https://en.wikipedia.org/wiki/Diving_watch#Legibility

But my question is the different marks a the 3,6,12 minute marks.

[Wasp]

Zodiac has used that convention for quite some time. Although I can't find quick and dirty proof I have a feeling it has to do with primitive dive tables. Decompression stops were not broken down to the specificity that they are today. Just general hang times for most dive profiles. Hang: 30ft 6min 20ft 3min 10ft 3min. < could be reversed I can't clearly recall that table from the 50's.

[Racer-X]

“The markers for 3, 6, 9 and (especially) 12 o'clock on the watch face and the zero marker on the bezel of analogue diver's watches are usually conspicuously styled to prevent disorientation induced read out errors.“

https://en.wikipedia.org/wiki/Diving_watch#Legibility

But my question is the different marks a the 3,6,12 minute marks.

Yep, I did not read that right, and will shut my trap until Carl shows up with the real answer.