Technical Review: The Breguet Marine Marchante Équation of Time

The Swiss watchmaker develops a staggeringly complex
masterpiece atop an estimable base, one of the world’s
thinnest automatic tourbillon movements.

By Jonathan Bues

Close up of the dial on the Breguet Marine Marchante Équation of Time Ref. 5887.

For a year that has been cast as among the most precarious for Swiss watchmaking since the quartz crisis, 2017 managed to bring out more than a few interesting high-end timepiece releases. Breguet captured considerable attention in Basel with a groundbreaking new watch that combines a slew of complications within an attractive design. Here, we focus not on the design of the Marine Marchante Équation of Time Ref. 5887, but on the mechanism at its heart. Though it should be noted that the mechanism itself played a larger than normal role in determining the timepiece’s appearance.

To make this unprecedented watch, whose complications include a perpetual calendar, an equation-of-time display, and a tourbillon, Breguet used the 581DR Caliber from 2013 as a starting point. At the time it was presented, the Classique Tourbillon Extra-Thin, which debuted this landmark movement, was the thinnest automatic tourbillon in the world. It remains one of the thinnest watches of its kind. This strikingly slim caliber with a tourbillon escapement and automatic winding now serves as a slender foundation on which Breguet can build ever more complex and exotic timepieces without producing Brobdingnagian timekeepers.

Close-up of the watch’s caseback.

In this case, Breguet enhanced the offering by incorporating an equation-of-time complication, which it married to a perpetual calendar. The equation of time is calculated and integrated into the watch via a figure-eight shaped cam that has been attached to the tourbillon cage and is visible through a cutout in the dial.

The equation-of-time cam is the most visually interesting  part of the movement: This is meaningful considering it comes affixed to another very impressive element, an ultrathin tourbillon with silicon components from Breguet. The visible cam atop the tourbillon guides the movement of a solar hand along the dial and shows the difference between true solar time and mean solar time, the latter of which laymen know simply as “the time.” As horophiles know, the length of actual days varies as the earth traverses its yearlong course around the sun. The shortest day is 16 minutes shorter than the standard 24 hour day. At its longest, this disparity stretches up to 14 minutes over 24 hours.

The movement’s complexity is obvious upon inspection.

These are just two of the complications that are easily observable from the dial side. The others include the aforementioned perpetual calendar display and a power reserve indicator.

Winding for the automatic function comes via a rotor that has been neatly tucked along the periphery of the movement. It keeps the movement thin while ensuring that the complex equation-of-time and perpetual calendar complications stay in sync and don’t need to be reset as long as the watch is worn daily.

The peripheral rotor, which allows this automatic movement to retain its slim profile, is ready to be set in place.

Viewed from the rear, the Breguet Marine Marchante Équation of Time Ref. 5887 is an artistic masterpiece. A historical nautical motif depicting the golden age of ocean explanation has been engraved on to the back of the watch. The Breguet Marine Marchante Équation of Time is available in two references. The first, in rose gold, is priced at $215,000; the second, in platinum, is priced at $230,400.

Close up of the dial on the Breguet Marine Marchante Équation of Time Ref. 5887.