Blancpain 1315

Thanks for sharing.  Any pictures of the watch/movement?

Except the open sapphire case back on the FiftyFathoms references, there are precious few 1315 internal views.

That being said, there are excellent photos by Hodinkee also featuring good review articles. WatchTime and the WatchPro site also have BP FiftyFathoms/caliber 1315 photos.

And then there is the Blancpain caliber 13P8, which is featured in Caliber Corner's caliber collection.. The 13P8 is a 1315 movement, slightly refined and found on the BP Gombessa Tech FiftyFathom references. These specialized FiftyFathom  dive references have a special dive time complication as well as a helium gas escape valve ala the Rolex Sea Dweller.

The 1315 caliber by Blancpain reflects the chronometer grade accuracy plus+ that well-designed  automatic watch calibers  may obtain through cutting edge horological engineering.

I am lucky enough to have currently and have owned in the past a few Blancpain watches with 1315 movements.

I am a fanatic when it comes to both Precision and accuracy of a watch. I am far far more demanding than C.O.S.C requirements.

I allow a cumulative error   of less than 1 second overall, that does not matter if its in one day or over several months.

this is very simple to do when a watch is so well manufactured and of high quality.

For example the watch I am wearing right now is a BlancPain Fifty Fathoms 42.3mm Titanium case and bracelet blue Dial and Bezel model reference number … 5010 12B40 98S

I have been wearing this watch since May second 2024 that’s approximately one month after its official launch.
The cumulative total of error this morning was +0.6 seconds.

I am no mathematician but that seems to be an average daily error of +0.0005 seconds per day.

During the 122 days of daily wearing and night resting off my wrist I have been in different climates from below zero to above 30 decrees C.  I have worn the watch both in and out of water and it has been used as a backup watch in several dives the latest of which was yesterday.

in none of the environments did the watch seem to struggle or loose any of its accuracy and / or percision.

The simple 1315 movement comes as close to perfection every time it seems 

The Tech Gombessa (Act 2) and even the X-Fathoms both have the base of tthe 1315 but are far more complex and both of those are exemplary as well  as they have also been placed on Wits hi Chronoscope and measured to the nth degree.