To say that this Chronometer is a mystery, is a sweet euphemism.
No hint of its existence in the Lecoultre archives, since they were lost.
But it has been mentionned in several documents, such as:
The Geophysic Leaflet:
A close up of a text, on the left part:
Some advertisings:
And a warranty booklet:
From the advertisings we know that: " The creation of the Master Mariner celebrates the 125th anniversary of the LeCoultre watch factory... Illustrated is the Master Mariner Chronometer- so accurate it qualifies for rating as a chronometer by authority of official observatory accuracy certificates.
18 K gold $ 395. "
So, this Chronometer was released in 1958, existed in yellow gold, with at least two different dials, as revealed by the picture from the warranty booklet.
These are the facts you can find on these documents.
Some questions remained without answers, such as the the productions years and numbers, and some other have been answered the day I was able to put my hands on a specimen, wuth the help of a collector who allowed me to take some pictures and to open its case back.
- The case: 36 mm big, around 9 mm thick. Snap case back. Does it exist in rose gold or in stainless steel, I don't have the answer. But no other version than the YG model was mentionned on the advertisings and booklets.
- The dial: As previously said, it seems that at least two different dials existed.
This one is different from the one pictured on the warranty booklet:
- The movement: This is the most intriguing part of this watch, as the only thing we know, when looking at the pictures of the dial, is that this is an automatic calibre.
But which one? The Cal 881 housed in the Geomatic was not used, still... And the P 478 BWSBr is manual.
The answer is found once you remove the case back.
Here, we have the Cal 476 / 3: It is a 17 jewels bumper movement, beating at 18 000 vibrations per hour, adjusted to 5 positions, and to températures without précisions on how many températures it was adjusted, though...
One important precision: This movement doesn't hack.
It is officially certified.
Its diameter is 29, 56 mm, for 6, 15 mm high.
The movement number ( 1, 310 xxx ) confirms it was made in... 1958.
We cannot say this movement is a champion of decoration and finish. But is this the most important for a Chronometer?