Thomas Mercer Britannica Unique Piece for Only Watch 2015

For its first participation in Only Watch, Legendary Marine Chronometer manufacturer Thomas Mercer donates the very first piece of its soon-to-be-released Britannica. This table chronometer is encased in a unique, dedicated cabinet. Made of steel and upholstered in white leather, it is home to an exceptional chronometer movement, sheltered behind a one-of-a-kind bas-relief dial.

The Britannica is a table chronometer of extreme sophistication. The aesthetics are the work of British furniture designer Jake Phipps. A practitioner of the geometric rendering of mineral crystals, he was inspired to create a sleek, slender and octagonal cabinet. The Britannica’s base and external structure are made of extensively polished 316L steel. It is also fitted with a set of extra-white crystals which provide an all-round view on the Britannica’s exceptionally polished and bevelled movement.

An additional touch of distinction of this truly unique timekeeper comes from the fine white leather that is signed by Foglizzo Leather, leading specialist in leather for the ultra luxury interiors of superyachts, vintage cars and private jets. This soft, pure leather covers the whole cabinet of the Britannica. The white exterior, combined with the blue of the dial, represents the official colours of Only Watch 2015. Having furnished some of the world’s greatest and most exclusive yachts, the know-how of this special partner enhances the seafaring universe of Thomas Mercer, a company proud to be a crucial part of the United Kingdom’s marine heritage.

The Only Watch Britannica stands out with its custom-made celestial map dial. Equally one-off, it represents the Geneva starry sky as it will appear on the night of the 2015 Only Watch auction. The hand-painted blue background is set with a bas-relief constellation map and Roman numerals made of polished steel. They are circled by an outer ring, also made with the bas-relief technique and made a dark shade of grey by galvanic deposition of ruthenium. Sharp angles and straight lines underpin and complete the case’s geometric design.

The Britannica is endowed with the TM0802 calibre. It features an eight-day power reserve, a trait indelibly linked to Thomas Mercer’s most famous historical chronometers. It is fitted with a fusee-and-chain transmission system, which acts as a gearbox, constantly changing gears in order to provide the movement with an almost constant level of torque, thus stabilising the movement’s frequency.

Thomas Mercer’s TM0802 calibre ticks at the rate of 14 400 vibrations per hour. True to the legacy of both British marine chronometers and Thomas Mercer, it is fitted with a spring detent escapement. Also known as “chronometer escapement”, it has proved the most accurate and reliable of all. It is now one of the rarest features in clockmaking. The escapement works in close conjunction with a balance wheel that is unique and specific to Thomas Mercer. The ovalising balance is an uncut ring of brass, fitted with regulating screws, and reinforced with a cross-bar made of invar. This reputable alloy helps it keep its shape, and therefore specific rhythm, while temperature varies. It is coupled with a cylindrical hairspring. All of these parts are located above the dial and visible through a set of extra-white crystals.

Technical details
Case
Octagonal shape for the main body, base and dial bezel
Made in 316L stainless steel with fine white leather and extra-white crystals
Dimensions: 333(h) x 240(w) x 152(d) mm

Dial
Two-tone type in stainless steel
Outer ring with minute indices in bas-relief and anthracite colour effected by galvanic deposition of ruthenium
Inner circle with constellations map in bas-relief and decoration in hand-painted blue
Roman numerals and hands in polished stainless steel
Open-work window with visible escapement

Movement
Calibre TM0802, hand wound, mechanical spring drive with fusee and steel chain system, 17 jewels, 8-day power reserve, frequency 2Hz (14.400 vph), spring detent escapement, ovalising balance oscillator with cylindrical weights
Hour, minute, small second at 12 and power reserve indicator at 6, rhodium plated and ruthenium finish with screws in blued steel, skeletonised back plate
Dimensions: 183(h) x 150(w) x 90(d) mm