Uncategorized Breitling 26 Oct 2023

Finding Longitude: Navigating the History of Timekeeping


Watch Wise

Website Admin


A dive in to the history of timekeeping at sea, finding longitude and Learn how Breitling changed the course of aviation


Finding Longitude. Hours, Minutes, Seconds, something we’re all familiar with - The face of a watch or, when given a quantity, a precise moment in time. However, replace ‘Hours’ with ‘Degrees’ and you get 00°,00,00 or in other terms, the geographic co-ordinate system developed originally credited to Eratosthenes of Cyrene, who composed his epic ‘Geography’, which is now lost to time but at one point was held in reverence at the seemingly mythical (though very real) Library of Alexandria in the 3rd century BC. Whilst the original text is now lost, it is referenced by name in many editions of subsequent works since, meaning the original history can be traced here.

Not all those who wander are lost.

— J.R.R. Tolkien, Author of The Lord of the Rings

The prime meridian

As the world is spherical, and so there are no 'starting points' - One must be created and agreed upon. This is called the Prime Meridian, with which to call "Zero degrees". One location of the prime meridian, that is the linear point running north-south marking the datum or ‘zero-point’ was selected by Ptolemy as ‘The Fortunate Isles’ or ‘Isles of the Blessed’. These islands continued to play the role of defining the prime meridian through the Middle Ages and were purported to lie west of Africa. They are semi-legendary, with some scholars agreeing that the islands have since submerged beneath the waves of the Atlantic – Others not-so convinced, but still curious.

At sea, I learned how little a person needs, not how much."

— Robin Lee Graham, Sailor

Finding Longitude

Finding Latitude was a relatively simple matter of determining the angle at which the sun sits above the horizon at noon – An excellent method would be to use a sextant, which is a tool still used by mariners today – A more ancient method would be to use a cross-staff (or Jacob's staff) the aim being to get the precise angle of the sun above the horizon at noon. A simple chart printed & held by every navigator worth his salt would be freely available to reference in order to derive his position above the line of the equator, whether it be “north of”, or “south of”. This could be calculated extremely accurately, even to within a few hundred meters. 

Finding Longitude is a little harder. The reason for this is that in the vast majority of cases, the method by which a navigator would determine their position west or east of the prime meridian (Now internationally recognised by the north-south line passing through Greenwich in London) would be to have a clock on board that is permanently set to Greenwich time, and a clock that is set to local time, easily established by the position of the sun above the horizon at noon. Now, this may at first seem easy – just bring two clocks, right? Well, we must remember that the year, for example, is 1600 & there are no watches or clocks accurate enough for the long voyages on swaying ships, as the balance spring hadn't yet been invented! Clocks were at the mercy of the pendulum, which were all but unusable on ships.

Sea Trials, and Harrison's H4

In order to develop a solution to the problem of navigating a ship & finding a ships' precise longitude at sea, UK parliament issued 'The Longitude Act'. Among other methods, was Harrison's H4 Sea Clock, the secret of which lied in its' rapid ticking, or 'beat rate' of 5/sec. in 1761, Harrison's son was allowed to voyage to the Caribbean in order to properly test his H4, against the Lunar Method. In February 1765, the Board overseeing the act recognised the significance of the H4, and approved its' use in vessels. Harrison had solved the problem of Longitude.

The quality of the box matters little. Success depends on the man in the seat.

— Manfred Von Richthofen, 'The Red Baron'

The Breitling Navitimer

Fast forward to 1952, the US Aircraft Owners and Pilots Association (AOPA) were in need of a chronograph watch for their members. In 1952, went to Willy Breitling, a manufacturer of Swiss watches, with their problem. Breitling's creation was an innovative instrument that would enable pilots to perform flight calculations, including average speed, distance traveled, fuel consumption, rate of climb or descent, and conversation of miles to kilometres or nautical miles. Breitling had solved several problems facing the pilots, all within the watch on their wrist.

At that time, calculations required a logarithmic slide rule. Willy Breitling therefore adapted the original logarithmic slide rule of the 1940s Breitling Chronomat for aviation purposes and integrated it into the watch's rotating bezel, surrounded by small beads to make it easier to manipulate.

For the name, what could be more evocative than Navitimer, a combination of navigation and timer. When the Navitimer was finally introduced to the AOPA, it was an instant success among the association’s members.

The very first Breitling Navitimer, designed for the AOPA, did not feature the Breitling brand name or logo on the dial. Its iconic 806 reference was not stamped on the caseback, and the watch was only distributed to AOPA members. However, just a few years later, around 1956, the Breitling Navitimer was made available on the open market, featuring the Breitling name above a stylized winged logo and not bearing any reference to the AOPA. It was then that it also received its now iconic 806 reference.

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