Blancpain

Indeed! Essentially the same movement in the Leman series, based on the Piguet 1150. This movement was used by many in the past (e.g. Breguet, AP, VC) but with a 70 hr. pr.

Jun 28, 2020,08:27 AM

Blancpain added the second barrel to gain the 4th day. And what a workhorse this movement has been! ("If it ain't broke, don't fix it.") Utilized since 1988, a comprehensive list of iterations is available at Grail Watch Reference, under "FP1150 Family."

Interestingly, the table lists the Ultra Slim PR's power reserve at 95 hrs. (cal. 11A4B—27.40 diameter, 2.80 high.) This is confirmed by the Blancpain website. But does this refer to the newer "Ultra Plate" series, with the pr indicator on the reverse side of the movement? The elegant piece here discussed is an earlier model. If we are talking the same caliber, though, are those missing 5 hrs. a casualty of the movement's thickness? The 1151 in my Leman date, though the same diameter, is listed at 3.25. Surely it couldn't be a matter of parts (the 11A4B is listed as having far fewer, at 131, whereas the 1151 has 210). How, exactly, would that many more parts make a watch more efficient?

There's the issue of silicone hairspring, as well, as some of the 1150 family have sported this upgrade for a number of years, and for those (like mine, below) with the more traditional nivarox spring, an upgrade is available at time of service. In any and all cases, those missing five hrs. may well be a matter of how the watch is positioned at rest, or the luck of the draw. At last timing, my Leman ran for 102:01:26. (A tad compulsive, you might observe. Well, all right; I was just so excited to have this marvelous instrument!)