After eight years, the inaugural Ferdinand Berthoud calibre FB-T.FC that debuted in the FB1 has reached the end of the road. When the FB1 was launched in 2015, it represented one of the most earnest exercises in recreating a marine chronometer for the wrist. The calibre FB-T.FC is an appealingly anachronistic, tourbillon movement with a pillar construction, Maltese cross stopwork and a chain-and-fusée mechanism. But more than a portable museum of 18th century technical solutions, it was also finished to a remarkable degree. Today, the brand is giving a curtain call to the calibre FB-T.FC with the Chronomètre FB 2T.

The watch will be produced in a limited edition of 38 pieces, as a tribute to the namesake 18th century Swiss chronometer maker who played an instrumental role in the development of marine chronometers and published the Traité des montres à Longitudes in 1792, 38 years after he was appointed master horologist to the king of France. The brand is offering a unique opportunity to fully customize the 38 watches, including the choice of case material, colour and finishing of the dial, and leather strap. While there are three base models available, each with its own distinct features, these can be further tailored to the owner’s preferences. The FB 2T.2 features a rose gold case and a black satin-brushed dial; the FB 2T.2-1, a rose gold case and a ruthenium satin-brushed dial; and finally, the FB 2T.1 is in white gold with a blue satin-brushed dial.

Notably, this marks the first time that the calibre FB-T.FC has been fitted in a round case and this particular aspect is not up for customization. As with all Ferdinand Berthoud watches, it is on the larger side with a case diameter of 44mm and a thickness of 14.3mm high; given the wonderfully elaborate architecture of the movement, it can hardly be anything else. But it wears smaller thanks to its short lugs, which are attached to the case band with bolts, while the crown guard and sapphire porthole are held in place by screws.

The German silver bridges in the movement have been replaced with three sapphire bridges, secured to the main plate by six polished steel pillars. They offer an unimpeded view of the movement, notably the large chain-and-fusée transmission system and the polished cone with a ruby-tipped feeler arm for the power reserve display. Despite being harder than German silver, the sapphire bridges are still bevelled by hand.

While this marks the end of the calibre’s run, its impressive, old-school enhancements to chronometry are still worth recapping. In contrast to the standard fusée where the chain wraps about the barrel and the fusée in one direction, the FB 1 features a reverse fusée where the chain forms a figure “8” as it wraps around the two components. As such, the fusée and barrel rotate in opposite directions which helps reduce the pressure on their pivots.

Both the barrel and fusée employ a “hanging” or suspended construction in that they are secured to the mainplate at the base, without an upper bridge to help reduce the height of the movement. The barrel and the fusée are linked by a 28.5 cm long chain comprising 474 links, which contributes to a high part count of 1134 components overall. Mounted on the barrel cover is a Maltese cross stopwork that restricts the turning of the barrel to ensure the extreme ends of the mainspring will not be used, effectively only ultilizing the portion of the spring when torque is most even. In so doing, it also limits how much the chain wraps around the fusée at full wind.

Visible on the fusée cone are the differential planetary gears for the purpose of maintaining power while winding. This is necessary in a watch with a fusée mechanism because the movement will stop when it is being wound as the fusée rotates backwards to rewind the chain and forwards when the watch is running.

Thanks to the sapphire bridges, the cone-and-feeler mechanism for the power reserve is visible right below the barrel. As opposed to the more common planetary differential system used for power reserves, this mechanism consists of a cone with a ruby-tipped feeler arm. The cone is driven up and down by a screw linked to the barrel – a system which itself acts as a differential gear system. It is accompanied by a spring-loaded feeler arm that measures the motion of the cone and transmits the state of wind to the power reserve hand.

Lastly, held in place by a blued arrow-shaped bridge is a titanium tourbillon carriage which houses a free-sprung 3Hz balance that is attached to an overcoil hairspring. Notably, this is a central seconds movement. Typically, the seconds hand in tourbillon watches is directly mounted on the cage of the tourbillon, which would rotate clockwise on the dial side. However, visible through an elongated aperture down the centre of the dial, the seconds hand is driven directly by the fourth wheel of the movement, which meshes with a tourbillon wheel of the same diameter and pitch that sits above the fixed wheel and drives the cage.

The watch’s certification as a chronometer by the COSC is no surprise, given the multitude of solutions implemented to enhance rate stability. Its highly elaborate construction is matched by equally accomplished finishing. Even the minutest part of the movement such as the stopwork and Maltese cross are elaborately decorated with a brushed finish on their top surfaces, polished and bevelled at their edges, with two sharp inward angles on the bridge for the stopwork. The three-arm tourbillon cage is particularly beautiful with fine, elegant spokes and a hub in the shape of a stylized triangle with pointed edges. The arrow-shaped bridge, on the other hand, has a brushed top surface, outlined by polished bevels that include two inward corners and one sharp outward angle.

With a more classical case shape, the Chronomètre FB 2T is a fitting swan song for one of the most beautiful tourbillon movements of our time.

Tech Specs

Movement: COSC certified manual winding Calibre FB-T.FC-2; hours, minutes and direct drive center seconds; power reserve display; constant force with fusee-and-chain transmission; 53-hour power reserve; 21 600 vph (3 Hz)
Case: Round with sapphire porthole; 44mm by 14.30mm; water-resistant to 30m; three base models available for customizations: rose gold with a black satin-brushed dial (ref. FB 2T.2), rose gold with a ruthenium satin-brushed dial (ref. FB 2T.2-1) or white gold with a blue satin-brushed dial (ref. FB 2T.1)
Strap: Hand-sewn leather strap with matching gold pin buckle; length-adjustable folding clasp available on request; various sizes available on request
Price: Starts at CHF 255’000 for the base models
Availability: Limited edition of 38 pieces