Zenith El Primero Chronomaster Grande Date Bi Color (51.2160.4047/01.C713)

This year, the Manufacture is pursuing its tribute to Christopher Columbus by introducing this heir to marine chronometers in a splendid interpretation calling upon the finest artistic crafts such as enamelling, engraving and micro-painting. This entirely hand-finished model issued in a 10-piece limited edition is accompanied by three major horological discoveries: a patented gravity control system; a fusee and chain transmission mechanism; and an exceptional frequency of 36,000 vibrations per hour.

On the dial side, Zenith opted to give pride of place to the horological feats incorporated in the watch, while maintaining an open architecture providing a chance to admire its three original mechanisms in action: the barrel with its fusee and chain transmission (at 10.30 and 1.30), gyroscopic gravity control system, and the high-frequency regulating organ at 6 o'clock. Yet this technical, three-dimensional appearance does not preclude considerable aesthetic sophistication, as well as the use of the finest artistic crafts: the three gold subdials (hours/minutes at 12 o'clock, small seconds at 9 o'clock, power reserve at 4 o'clock) are finely guilloche, enamelled in white and fitted with blued steel hands and screws echoing the grand watchmaking traditions. The plate has been entirely hollowed out by hand so as to leave only the Zenith logo and a flurry of stars standing out in relief; and the troughs thus created have been filled with midnight blue lacquer. The counterweight of the gravity control system has also been enhanced with a sophisticated and poetic touch by a hand-crafted micro-painted depiction of the Southern hemisphere.

The back of the Academy Christophe Colomb Hurricane Grand Voyage bears a lively evocation of the famous navigator's many adventures. This authentic miniature painting was created by the finest specialists in various artistic crafts using a sophisticated system of gold appliques fixed directly on the movement. In the foreground, on either side of the mechanism reminiscent of the gimbal suspension typical of marine chronometers, one may admire the finely engraved portrait of Christopher Columbus along with a sextant. The background bears a reproduction of the Santa Maria, the flagship with which Columbus sailed on his first voyage in 1492. The tiny manually cut-out and micro-engraved decor depicts the vessel in abundantly rich detail, particularly in terms of the ropes and rigging. The various sails, crafted in enamel on a cloisonne base using an engraved champleve technique, are adorned with the famous red cross - replaced on one of them by Zenith's famous guiding star in a nod to connoisseurs.

Behind the sailboat, the going-train bridge has been chosen to represent the ocean with a background engraved with tiny waves and then coated with a layer of translucent lacquer. In the background, the barrel bridge opens up the horizon with a micro-painted decor depicting a sky divided into day and night. In a subtle detail, the watchmakers of the Manufacture have arranged the movement structure in such a way as to reveal a small gilded gear train evoking sunrise or sunset. Integrating this decor called for a wealth of ingenuity, including finding points to which the applique elements could be fixed, while reducing the movement thickness and the spaces between the calibre and the ornamentation to an absolute minimum (less than a tenth of a millimetre beneath the sails). Entirely hand-finished, the adornment of the Academy Christophe Colomb Hurricane Grand Voyage makes each watch a unique work of art - and a true collector's watch.

This model pushes the boundaries of time measurement by combining three mechanisms guaranteeing enhanced precision: a regulating organ with a high oscillating frequency (36,000 vibrations per hour) for dividing time into tenths of a second; a fusee and chain transmission system compensating for the inevitable variations in the force of a barrel while it is unwinding; and a patented gravity control module serving to neutralise the effects of gravity on the rate of a watch. In other words, it successfully solves the problems relating to actually wearing the watch (gravity) and to the length of time it can run independently (a drop in torque), while simultaneously ensuring remarkable precision in time measurement (linked to the oscillation speed of the balance). The movement comprises 939 parts, including 354 for the calibre itself that in turn houses the 173 elements of the gravity control module; while the fusee and chain system comprises 585 parts.

As a mechanical watch gradually winds down, the movement loses amplitude (corresponding to the balance-wheel's angle of oscillation) and thus becomes less accurate. The fusee and chain transmission system serves on the contrary to keep the driving force perfectly stable throughout the full power reserve - with the helicoidal shape of the fusee compensating for the progress reduction in the force of the barrel.
The majority of 16th, 17th and 18th century pocket watches were equipped with a fusee, but today very few watch manufacturers are capable of transposing and fitting this mechanism within the confines of a wristwatch.
Transmission between the barrel and fusee is handled by an 18 cm-long chain comprising 585 parts. This highly complex construction features alternating double and intermediate links. Once assembled, it is capable of withstanding a traction force of more than 3 kilos.
Throughout the power reserve, the mainspring transmits its energy to the fusee via a chain that wraps itself around the barrel. By adjusting the variations in tension, the fusee regulates the force that is passed on to the going train - and thence to the silicon escape-wheel fitted inside the gyroscopic carriage. While it takes more than 50 hours (the power-reserve duration) for the chain to wrap itself around the barrel, winding via the stem provides a fascinating sight. These few seconds enable the fusee and the barrel to turn in opposite directions so that the chain wraps itself back around the fusee.
The shape of the fusee was dictated by the optimal force that the Zenith master-watchmakers wished to give the barrel. Its grooved conical contours as well as its dimensions are the result of lengthy and particularly complex complications performed for each of the seven construction stages.

While fusee and chain transmission eliminates variations in isochronism (the equal duration of the oscillations), the Academy Christophe Colomb Hurricane Grand Voyage also cancels out another effect that is detrimental to the rate of a mechanical watch: the influence of gravity.
Working on the principle that keeping the regulating organ in a horizontal position engenders the best possible balance-wheel amplitude and thus results in optimal timekeeping precision, Zenith devised and patented a revolutionary module enabling the "heart" of the movement and the escapement to remain constantly in this position.
The gravity control system is also a tribute to history, since it is inspired by the marine chronometers that Zenith used to produce, borrowing from these legendary instruments the principle of gimbal suspension introduced in the 16th century on marine compasses so that they would stay horizontal despite the pitching and rolling of the boat.
The gravity control system with its self-regulating gyroscopic mechanism serves to maintain the regulating organ in a permanently horizontal position whatever the angle of the wrist and thereby represents the ultimate evolution of the marine chronometer.

This model deserved to be presented to its best advantage. The Academy Christophe Colomb Hurricane Grand Voyage comes in a precious mahogany box featuring ox bone inlays and that can also serve as a humidor with a capacity of 80 cigars. In homage to Christopher Columbus, this box is adorned with a screen-printed motif on parchment-style papyrus reproducing Waldseemuller's planisphere (1507), the first world map to mention the name "America".