Made in Switzerland circa 1930, 64mm, silver case, manual winding movement, white enamel dial with Roman numerals, accessorized with Ulysse Nardin fitted box and key. Blue steel indicators
Functions: hours, minutes and small seconds, running time indicator and marine chronometer.

For sailors, the correct time is fundamental in determining the longitude. With an accurate timepiece, a navigator can work out his exact location. In early days before the birth of marine chronometer, it was essentially impossible for sailors to know the time, traditional clocks were incredibly inaccurate but the pendulums of the clocks swing wildly even when the timepieces were mounted in gimbals.