skyeriding
900
Sounds about correct
Apr 12, 2022,01:23 AM
The red 12s chronograph hand (1/10th second) simply spins five times faster than the regular chronograph 60s hand. They are effectively tied together in all start/stop/reset functionality - one can be forgiven to think at first glance "why not just gear them directly together in a 5:1 ratio?" (which of course, is not that straightforward - hence all the patents and the complexity). And as you've described, after 12 seconds, the red 12s hand has less value as all it shows is a magnified scale view to be read in conjunction with the regular 60s chronograph hand.
The regular chronograph seconds and minute counter indeed work as normal per your description.
I find the Patek press material slightly misleading when they state that there are two "independent chronograph mechanisms" - this implies that both can be separately start/stop/reset at will. This is not the case, as previously mentioned. Having two independent chronographs would require two column wheels and a significantly more complex mechanism, which will likely occupy the empty space on top of the balance wheel and start to look more complex than a Double Split. What I believe what they are trying to promote is that they had to fit two lateral clutches within the same movement to drive the two hands in parallel, which is the reason for the complexity.
Regards,
skyeriding