Zenith Chronometer Telemeter Quad Tachymeter

What mouthful of horology!

To understand this very special Zenith El Primero, one has to travel back to the 1940s. To a time when mechanical chronographs were rare, expensive and built for a specific purpose: as essential military tool watches. A good quality military chronograph was so rare and precious that they were only issued to high ranking officers; and hence the name has stuck to this day.

In general the four most common types of chronographs are: a simple stop watch for timing an event, a stopwatch with tachymeter scale for calculating speed over distance, a chronograph for measuring pulse (also known as a doctor's watch) and a chrono with telemeter scale.

During WW2 it was the telemeter chronograph that was especially sought after and most useful for a field or naval officer.

The scale is graded from 0-20 and often, but not always, marked as 'Telemeter Km'. The 'mile' version was graded as 1-13. Telemeter was used to measure distance from the firing artillery. The stopwatch was activated when the blast was seen, then stopped when gunfire was heard. For example, if the timing between two events was 25 seconds, then enemy's tanks were 8.4km away.

The second useful scale on a chronograph was tachymeter.

It allowed measurement of speed over a predefined distance. For example, if a car travels 1 kilometer in 15 seconds, than its speed is 240km per hour. This calculation can be read directly from the bezel. This type of tachymeter is also known as "base 1000" because the length 'base' is 1000 units, but there is no need to specify kilometres or miles, because unlike with telemeter, calculation is the same for both units of measurement.

During the 1940s two common tachymeters were in use: those to measure speed of aircrafts and those to measure speed of land vehicles. It is easy to tell the difference: the fast flying aircrafts tachymeters start at 900, while land speed was not expected to exceed 300km.

In the 1950s and 60's racing drivers pushed the 'need for speed' even higher, as seen on the Speedmaster tachymeter bezels.

However, those direct reading tachymeters with high 'base scale' were less useful for slow moving means of transport like - bicycles or horse riders. Obviously, a simple calculation would be sufficient to measure speed, but users preferred direct reading from what we call double and triple tachymeters. A triple one would have three different bases on the dial, incorporated in a spiral.

For example: in the case of Zenith, the most outer scale reads speed from 60 - 500km, the middle one from 30 to 60, and the central from 20 to 30 and the most inner scale from 15 to 20. In order to distinguish between tachymeter, chrono and telemeter, such chronographs would have either red or yellow numbers and a corresponding chrono hand.

Telemeter quad tachymeter is a very cool timepiece, highly respected for its historical utility and clearly defined purpose. In the case of the Zenith El Primero, an additional date and automatic function with high beat escapement makes the watch stand out from the rest. A keen and sophisticated watch collector would easily recognize the value and uniqueness.

Price? A bargain! Originally sold for around $12,000, this rarely seen Zenith is priced at a very affordable $7,600. Complete set, steel, 44mm case. Currently fitted on a NH Horween leather strap, but will be supplied with the original Zenith deployant clasp.

NH photos of the watches documented are in Giampierro Negretti "Patek Phillipe" book.

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