Thomas Mercer, Marmor Hotavlje and Winch Design are pleased to announce the release of their latest collaboration – Chelys, an horological sculpture fusing the respective arts of marine chronometry, stone carving and yacht design.

The piece was exhibited on Marmor Hotavlje's booth on the latest Monaco Yacht Show

Winch Design is one of Britain’s most renowned superyacht design studios based in Barnes, London. Founded in 1986 by superyacht designer Andrew Winch, together with his wife Jane, the business has grown over the last 30 years. The company is a full-service design and architecture studio specializing in the exterior and interior design of yachts. Paying particular attention to quality and detail, Winch Design takes the vision of his clients and expands their imagination in order to produce extraordinary, indeed unique designs.


Established in London in 1858, Thomas Mercer is a name forever synonymous with the marine chronometer, the timekeeper invented for determining longitude at sea. Today the company diligently and proudly upholds the tradition of British clock-making by manufacturing exclusive marine and table chronometers that grace the interiors of the finest yachts and residences.


Led by the Selak family, Marmor Hotavlje is one of the foremost stone-cutting companies in the world. In 1721, the residents of the small Slovenian village of Hotavlje discovered the riches hidden in their mountains and carved their first stone. Thus, began a rich tradition, which, through generations and generations of stonecutters, transmits knowledge, skills and love for their craft. In 1948, the workshops at the foot of the quarry joined the Marmor Hotavlje company whose pride today in its history and heritage parallels its excellence in a variety of international projects.

Every single stone piece of Chelys was hand made, thus making it even more unique than it is

Ivory onyx shell from a massive piece together with the timeline and the pedestal

The word Chelys derives from the Latin form of the original Ancient Greek χέλυς (tortoise) which describes a musical instrument made of a shell, its convex form resembling those of this fine chronometer.  According to the fable of his Homeric Hymn, Hermes found a tortoise near the threshold of his mother’s house and decided to hollow out the shell to make the sound box of a seven-stringed instrument, thus inventing the first lyre of the Ancient Greeks.

Chronometer is distinguished by its rare one impulse per oscillation, resulting in its individual sound, featuring one lound and one soft beat


Andrew Winch, founder and creative director of the eponymous studio:

“The sinuous and sophisticated lines of the Chelys are carved out of ivory onyx, a semiprecious natural stone with immaculate crystalline background and evocative waves undulating through its structure. Named after the Ancient Greek word “ὄνυξ” (nail), legend says that one day Cupid clipped the divine nails of Venus with an arrow head while she was sleeping, and the Parcae (the three daughters of Zeus) transmuted them into stone, so that no part of the divine body could ever be destroyed. Rare and precious, it has been considered a luxury staple since ancient times. Measuring 44x39x22cm and weighing 25 kilos, this sculpture is crafted through a meticulous process of using traditional hand stonemasonry, impeccably executed by Marmor Hotavlje’s skilled artisans.”


“It was an honour to have collaborated with Thomas Mercer alongside Winch Design on this inspiring project” adds Marmor Hotavlje’s managing director Tomaž Selak. “While stonemasonry and precision horology are art forms in their own right, a true work of art is where the artist uniquely combines one or more art forms by conferring a symbolic and incomparable value. With the Chelys, Andrew Winch shows his unique talent as an artist by first imagining a superb onyx sculpture – already a work of art per se – and then inspiredly fusing it with a chronometer movement to elevate it even further, to the ultimate status of horological sculpture.”


With a case inspired by a mythological musical instrument, the movement had to mirror it in greatness, and its melody no exception. Like every Thomas Mercer mechanism, the new caliber TM8004 sports the sine-qua-non specifications of a marine timekeeper including the special spring detent escapement. Also known as the “chronometer escapement”, the spring detent is distinguished by its rare one impulse per oscillation, resulting in its individual – and very appropriate for the occasion – sound, featuring one loud and one soft beat.


Among the other subtleties of this precision timekeeper, the ovalizing balance for thermal compensation and the beautiful chain-fuse drive. The horological equivalent of an infinitely variable gearbox-speed, the latter equalizes the waning force of the mainspring by delivering the mechanism an ever constant amount of energy. As the force decreases, the chain moves from the top to the base of the cone, increasing its leverage to keep the torque constant.


The movement is housed in a tube case made of extra-white crystal, offering an all-around view of the inner workings which can be admired in their entirety. The elegant open-work dial magnifies the intricacies of the multi-complicated movement and its stone setting pairs perfectly with the onyx body. The hands are steel-made, hand-finished with bluing technique.


Alessandro Quintavalle, Thomas Mercer’s managing director: “It is truly a privilege to collaborate again with a world-class name such as Winch Design on another creation embodying their ethos of beauty, uniqueness and perfect proportion. After the success of the incomparable Nautilus, Chelys takes the concept of horological sculpture to the next level by relying on the world-class masters of Marmor Hotavlje to explore the endless possibilities of stone”.

A truly unique celebration of horology, design and stone-carving, Chelys was unveiled at Monaco Yacht Show 2019 - indisputably the leading event of the superyacht industry

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