Jumping For Joy: Ferdinand Berthoud Unveils The Chronomètre FB RSM With Deadbeat Seconds
With the help of a young apprentice watchmaker, the brand has added an independent deadbeat seconds complication to its signature fusee-and-chain tourbillon movement.
Since Chopard Group and its co-president Karl-Friedrich Scheufele rekindled the Ferdinand Berthoud name with the launch of the FB1 in 2015, Chronométrie Ferdinand Berthoud has become synonymous with its fusee-and-chain tourbillon movement. Indeed, it has even come to form the basis of most of its high-end timepieces.
Now, the brand has come out with a fresh take on it; by adding two new complications: independent deadbeat seconds, which is visible on the dial side of a regulator display, and a stop-seconds mechanism. The result is the Chronomètre FB RSM, with the SM standing for seconde morte, French for deadbeat seconds.
Here, the idea of combining deadbeat seconds with a regulator display comes from Ferdinand Berthoud’s Marine Clock No. 8 from 1768. What’s more, in keeping with the legendary horologist’s devotion to passing on knowledge and training new watchmakers, the brand invited a young apprentice watchmaker from the University of Neuchâtel to help develop the Chronomètre FB RSM’s deadbeat seconds mechanism as part of his graduation project.
Diving Deep into Deadbeat Seconds
First, let’s do a quick recap of the terminology. “Deadbeat seconds” – also called “dead” or “jumping seconds” – is when the second hand advances in steps of one second instead of the usual sweeping motion of mechanical seconds. And it was this complication that, as a part of his university work, the unnamed student watchmaker apprenticing at Chronométrie Ferdinand Berthoud researched the history of and explored the various ways in which deadbeat seconds can be achieved in clocks and watches.
He found that the best option was to incorporate something called a renvoi fou. Basically, it entails adding a few more gears of varying sizes and a sizeable curved lever spring whose solitary tooth holds and releases the controlling gear for the central seconds hand, which, in turn, is directly driven by the 60-second tourbillon.
As unbelievable as it may sound, the bourgeoning watchmaker helped Ferdinand Berthoud model how the mechanism would work in a movement that now features a balance-stop device enabling the tourbillon to be halted to the second, for ultra-precise time-setting.
The Challenge of COSC Certification
Faithful to its name, Chronométrie Ferdinand Berthoud is known for the precision of its watches and the COSC certification individually awarded to each one of them, achieved by pairing a gravity-fighting tourbillon with a torque-taming, constant-force fusee-and-chain mechanism.
It wasn’t a given that the Chronomètre FB RSM would be capable of following in this tradition of certified timekeeping precision. In fact, a lot of deadbeat seconds movements fail to achieve COSC certification. That’s because stopping and restarting the seconds hand involves stopping the gear train, storing the torque it continues to produce during this pause, then releasing it in one go after each second.
If the essence of a constant-force movement is the regularity of the torque, then you can imagine that interrupting its flow 60 times a minute without compromising its linearity is a tricky feat to manage. But manage it Ferdinand Berthoud did, by ensuring the deadbeat lever spring led to only a minimal loss of amplitude at each jump of the seconds hand. And so, the Chronomètre FB RSM has duly received the COSC thumbs-up.
Alluring Regulator Dial
The nice thing about the Chronomètre FB RSM’s deadbeat seconds mechanism is that much of it is visible through an aperture at 9 o’clock on the rather fetching regulator-type dial. Cut into the 18K gold dial plate, and as a tiny nod to the Marine Clock No. 8, this aperture takes on a figure-eight-shape. Reinforcing the reference is a hand-engraved “No. 8” at 6 o’clock.
While the deadbeat seconds are obviously the main event here, we shouldn’t forget the hours, indicated on a rotating disc at 2 o’clock, and the minutes (marked off by a facetted, skeletonized hand) on a sub-dial at 12 o’clock.
There is also a 53-hour power reserve indicator, but it’s only visible on the back of the watch. However, the back is certainly worth checking every now and then because you’ll be rewarded with views of the inverted fusée, mainspring barrel, plus the stopwork and tourbillon supported by an eye-catching arrow-headed bridge. Finally, as you would expect from Ferdinand Berthoud, the hand-finishing is superlative.
Pricing & Availability
Last year, Chronométrie Ferdinand Berthoud announced that its limited editions would, from then on, be defined by the number of movements made (a number stated from the outset) to help ensure the rarity of its timepieces while still giving collectors the possibility to personalize them. In the case of the Chronomètre FB RSM, that number is 20.
Thereafter, customers will be able to choose the shape of the 44mm case (round or octagonal) and the case material, from 18K red gold, 18K white gold, 950 platinum, and carburized steel, as well as the tonality and finishing of the dial plate, with different PVD treatments available. The brand is open to studying all client requests, including further customizations, which you can expect will cost extra.