As mentioned in an earlier article on marine deck chronometers, these overgrown pocketwatches are the direct descendants of John Harrison's H4 of 1764, the solution to the longitude problem, and thus represent the epitome in portable mechanical timekeeping. While the competition amongst manufacturers to provide ever-more-accurate wristwatches continued until electronic miniturization and economy overwhelmed mechanics in the 1960s, in the more demanding (and less economically constrained) world of military and official timekeeping, the contest was already over by the end of WWII. Although deck watches would contiune to see commercial service for many years, their development ceased. The quest to provide the ultimate in mechanical chronometric accuracy and reliability over long periods and under harsh circumstances ends, with these watches as final testimony.
Like its brethren, the present watch is all business, with its brushed silvered dial, blued-steel poire hands and simple black Arabic numerals and track. The movement ticks five times per second, so the smallest markings exactly correspond to the second-hand's progress. The case is sterling silver, a reasonable choice at a time when less noble metals were dedicated to military arms and equipment, and 59mm diameter, oversized for a pocketwatch but among the smallest of deck watches.
As one should expect of the great house of Vacheron & Constantin, this movement is a breathtaking combination of state-of-the art mechanicals and immaculate finish. The 21-jewel, 21-ligne (about 47mm diameter) caliber 166 is a full-bridge design and features a swan's-neck regulator, Guillaume alloy bimetallic split balance, and overcoil blued-steel hairspring. While deck chronometers' movements typically show excellent functional finish, V&C have gone far beyond that standard, providing smoothness, polish and a glow generally reserved for cost-no-object watches. :
Black-polished endcap for the escape jewel (oddly aligned), a bit of the bimetallic balance, and one end of the fabulous anchor with pallet:
Atop the main bridge is an elegant little cock which carries the jewel for the center-seconds; the spring lightly presses on the stem to prevent the hand wobbling, a typical solution for an indirect center-seconds movement. Excellent Geneva stripes and polished anglage all around, beautiful gears with exceptionally smooth teeth:
This delightful curve of steel tensions the barrel click. It is fastened to the perlaged base with a screw, and the little round-headed pin in its matching countersink assures it stays in the proper position. Even the winding teeth of the barrel are beveled and brought to a high polish!
For safe transport the watch rests in a fitted brass carrier, and is topped with a protective window with screwed-in bezel. The whole is fastened to a hinged and latched mahogany box.
In use the entire setup would look like this. The carrier accomodates the stem so the watch can be wound and set without removal: