Blancpain Caliber 13P8 Watch Movement

Manufacturer	Blancpain
Caliber Number	13P8
Base Caliber	Blancpain 1315
Type	Automatic, self-winding mechanical
In-House?	Yes
Lignes	13”’
Diameter	30.6mm
Height	5.65mm thick
Jewels	35
Number of Parts	204 components
Vibrations Per Hour	28,800 bph (4Hz)
Power Reserve	120 hours (5 days)
Barrel Count	3
Rotor	18K gold, signed “Gombessa Expeditions”
Anti-Shock Device	KIF
Balance	Glucydur, free-sprung
Regulator	Gold screw inertial regulation, no fine-tuning device
Hands Count	4
Functions	Central hours; central minutes; central sweeping seconds; central 3 hour dive-time hand
Hacking Seconds?	Yes
Country of Manufacture	Switzerland, Swiss made
Known Models	Blancpain Fifty Fathoms Gombessa Tech 70th Anniversary Act 2 (ref: 5019 12B30 64A)

The Blancpain caliber 13P8 is a 4-hander, no-date, automatic movement found in the brand’s Fifty Fathoms Gombessa Tech 70th Anniversary Act 2 model (47mm diameter, titanium, $28,000 USD) that was released on February 16, 2023.

This in-house caliber is adjusted in 6 positions from the factory. It has 35 jewels with a total of 204 parts. The 13P8 also has an extra long power reserve of 120 hours, thanks to its 3-barrel design.

Some of the topics covered in this caliber listing:

3 Hour Dive-Timer:

The cal. 13P8 is equipped with a 3 hour dive-time complication, which has a fourth hand (similar to a GMT) that rotates every 3 hours. Combined with a unique layout on the bezel, this feature makes it easy to time a dive.

Below you can see the markers on the bezel that work in unison with the Dive-Time hand: 30 (minutes), 1 (hour), 1:30 (1.5 hours), 2 (hours), 2:30 (2.5 hours).

Gombessa Expeditions:

You may notice that the 18K gold rotor is signed Gombessa Expeditions. Here is more about what that means:

“Laurent Ballesta’s Gombessa project focuses on studying some of the rarest, most elusive marine creatures and phenomena on Earth. Ballesta and his team use state-of-the-art closed-circuit rebreather diving techniques to reach extreme depths and bring back unique scientific data, photographs, and videos. Their activities are consistently marked by triple challenges of a technical, scientific and artistic nature. To date, there have been five Gombessa expeditions, all underwritten by Blancpain.” –source

Front and Back:

Despite what it looks like in the first image above, the 13P8 is an automotive movement. The image simply shows the movement with the automatic wind unit removed. This is to show the complete finishing of the movement without being obstructed by the rotor.

How to Reset the Dive-Time Hand?

You can’t. That’s one of the cons of this movement. Rather than setting the hand independently, you’re supposed to rotate the bezel to line up the diamond shaped marker with the hand in its current position. From there, you can begin to calculate your 3 hour dive time. If you thought that’s what the crown at 10:00 is for, you’re mistaken. The crown at 10:00 is for the helium release valve.

Video:

Additional Images:

Watches with this movement:

Blancpain Fifthy Fathoms 70th 5019 12b30 64a 13p8

Additional Resources:

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Blonkpon

1 year ago

The movement isn’t even that big so why is the watch so huge? Who is diving with a 47 mm watch on their wrist? I’d be all over it at 40-42 mm. 47 is stupid.

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Ona

Reply to Blonkpon

Using a divewatch as a dive instrument, size is a feature and 47 mm is anything but stupid. E.g. Oris Aquis Depth gauge (45.8 mm) is pretty good, and one has to remember that the watch is most likely worn on top of a neoprene suit or a rubber cuff. The Gombessa ticks of a lot of boxes for the perfect backup and is probably the best mechanical diver watch money can buy for it’s purpose. I consider it THE reference to measure anything else by. I have dived with sub 40mm, and they suffer in legability and use of… Read more »