On the wooden beam: Jaeger-LeCoultre 24002.42 Prototype

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Earlier I showed you a wrist shot of the regular production Jaeger-LeCoultre reference 24002.42 Master Mariner Chronometer.

The last serie production Chronometer from Jaeger-LeCoultre. Later to be replaced with the 1000 Hours Control…

This time I would like to show you the prototype version of the same!

The Calibre 906 which is used in all the reference 2400X Master Mariner were, according to some sources, in production between 1973 and 1975.

This prototype have a movement number corresponding with 1972-1973 which fits into that time frame.

Jaeger-LeCoultre 24002 prototype – on the wooden beam

Over the years I have spotted four or five more of these prototypes. To my understanding there were at least T.W.O dial versions and two case versions among these prototypes.

One like mine, with silver dial and one blue dial, both with “fabric texture” pattern.

The two cases differs in the lines and bevels of the lugs. One version with more pronounced bevels and sharper lines between the side of the case and the upper part of the case – closer or same as used on the final version of the 24002.

The other version – as my watch, have a rounder transition between the side and the upper part of the case. Less clear bevels and lines…

You might think it’s because the case been polished, that was my initial thought as well… But when checking closer, there is more material over the lugs on this prototype than on the final version of the watch!

Which rules out over polished unless the prototype case were much thicker than the final case….

Jaeger-LeCoultre 24002 prototype – fabric texture dial

During that time period, Jaeger-LeCoultre had several similar cases, both with clear facets / bevels and rounder.

Jaeger-LeCoultre catalogue – Master-Quartz 1975

In most documents the 24002 is illustrated with a red seconds hand as on the prototype but most of the final 24002 I have seen have a black seconds hand. Same goes for the Chronometer text on the dial. In most documents it’s there, the “Chronometre Automatic”, but very few dials can be seen with the text.

A bit strange is that Jaeger-LeCoultre used the “Chronometre” in French and “Automatic” in English…

Jaeger-LeCoultre catalogue 1975

Here is another document showing the 24002, this time without the Chronometre on the dial, but still with a red seconds hand.

In the specifications – no mentioning of Chronometer, but as far as I know, all 24002 had the Chronometre engraving on the case back. So I believe all 24002 very Chronometers, with the exceptions for the prototypes.

To use the term Chronometer on a Swiss watch was regulated by the industry and I don’t think Jaeger-LeCoultre would have taken the risk of using the Chronometre on any of their watches if it wasn’t a Chronometer.

Jaeger-LeCoultre retail sales catalogue 1975-1978

Here is a couple of side-by-side shot of the 24002 prototype and the 24002 final version.

The final version with the Chronometre on the back.

Jaeger-LeCoultre 24002 – left prototype, right final version

And here, the prototype engraving.

Jaeger-LeCoultre 24002 – left prototype, right final version

On the wrist the Jaeger-LeCoultre reference 24002.42 Master Mariner prototype is a super cool watch! Big, Funky 70’s – due to the thin bezel, the dial looks very big.

A wonderful watch with a “hidden secret” only to be seen if you take it off your wrist…

Jaeger-LeCoultre 24002 – on the wrist

Cool and easy to read, but to be honest… I am not a big fan of Day-Date watches… Not due to the looks but due to the process of setting the day and date…

I will return with a closer look on the regular version, stay tuned!