Prototype 1938

3646 watches with dodecagonal (12-sided) bezels bearing “Officine Panerai – Brevettato” engravings are/were believed to be the early prototypes, specifically produced for demonstration purposes.

There are two very prominent pieces worth mentioning. One of them has a beautifully faded Radiomir Panerai dial and was already discussed in one of my articles, the other has a “California” dial and a case which looks like new. The latter watch is known as the “Prototype 1938” with an early and unusual movement.

According to the book “Panerai – Una storia Italiana“, the first Ref. 3646 watches were delivered to G. Panerai e Figlio in 1940. The production date for this “Prototype 1938” cannot be accurate and is probably a relict of the early days of Vintage Panerai collecting.

“Prototype 1938” Panerai Ref. 3646 Type A, 1009498


History of 1009498

According to information I was able to find on old forum posts from 2008, Mr. Ralf Ehlers – a renowned German Vintage Panerai expert – told other forum members that this watch was originally sold by Mr. Francesco Ferretti to a German collector in 1996.

Seven years later in 2003, this watch was sold through the German auction house Dr. Crott for Euro 55.000 (plus 20% Premium). The watch apparently remained in Germany and found its way to the very same auction house again in 2008, where it was sold on May 17th for Euro 108.000.

Excerpt from the 77th Dr. Crott catalogue from 2008, Lot 167


Mr. Ehlers appeared to be satisfied with the achieved price of this specific piece. He wrote: “Makes a total of Euro 108.000 for Lot 167, including surcharge, that is ok. [thumbup]

Das macht für Lot Nummer 167 inklusiv Zuschlag ca. 108.000 EUR, das ist okay. [thumbup]

This watch reappeared on the market in September 2013. It was announced by Antiquorum for an auction held in New York, but for unknown reasons it disappeared from the list.


The movement

This watch has, as I mentioned before, a very interesting and unusual movement. It is not the regular Rolex 618 Type 1a one would expect in such early (1938) watch.

In the early days of Vintage Panerai collecting this kind of movements were considered to be the very first movements with only 15 Jewels.

Movement of Ref. 3646, 1009498
Movement of Ref. 3646, 1009498


Obviously the movement we see in this watch has a lot more in common with a Cal. 616 than with a Cal. 618. The bridges have the typical Cal. 616 layout. The five Côtes de Geneve (Geneva stripes) and their position on the bridges are typical for movements made after 1956. Early movements until 1944 had 7 Geneva stripes.

The main plate of this movement appears to be from a movement before 1956, as it bears the old style pallet fork bridge.

Comparison pallet fork bridge (left: until 1956, right: from 1956 onwards)


Bridges with the typical Côtes de Genève style after 1956 belong to movements with the newer L-shape pallet fork bridge.

Comparison Cal. 616


The balance cock of the movement in question is from an early movement, recognizable by its pre WW2 AR/FS engravings. The finish of this bridge is different than the other bridges, with a distinctive discrepancy in color, and could be from a Rolex 618 Type 1, as it features a Breguet overcoil hairspring. The ratchet wheel with the swirl finish could also be from a Rolex 618 Type 1. The crown wheel has the typical post WW2 finish.

This movement is obviously made from parts of different time periods. The old balance cock and the ratchet wheel could have been installed to make it look like an old movement. I cannot conclusively tell whether the Rolex engravings are genuine or not. Rolex started only in the mid 1950’s to engrave “Geneva” on their movements. This detail corresponds at least with the Côtes de Genève from 1956 onwards.

The engravings say “17 Rubis Swiss”. This movement could indeed have 17 Jewels, considering the jewel for the centre wheel on the train bridge and “possibly” a cap stone for the escapement bridge on the dial side.

There is a similar movement in a modified 3646 with “Dots” dial from the 1960’s. It cleary bears a Cal. 616 stamp on the barrel bridge. The Côtes de Genève in the area of balance cock do not match at all, which makes it pretty obvious that the balance cock with the flat hairspring is from an earlier Cortebert 616. A movement with this type of Côtes de Genève should have a L-shape pallet fork bridge.

Cal. 616, modified 3646 “Welded Lugs”


The following chart shows how Cortebert Cal. 616 evolved compared to Rolex Cal. 618 (Click for larger view).

Evolution Cortebert calibers 616 and 618
Evolution Cortebert calibers 616 and 618


As a side note, I had only a very small picture of movement of the “Prototype 1938” from an excerpt of the catalogue. I inquired with the German auction house whether they could send me a high resolution picture. First they said all pictures had been deleted. After kindly asking if they could at least make a shot from the old catalogue, and disclosing why I needed the pictures they simply did not answer anymore.


Movement ring and case

The movement ring of this watch is from a later 3646 Type D, E, F or G. Early movement rings until Type C were made of brass and the color is very distinctive. The way the crown tube was soldered to the middle case is very characteristic for late 3646 watches from 1944.

Comparison movement ring


This middle case is most certainly not from a Type A watch as the case back suggests. Only a full profile view can provide certainty. However, if I were to speculate, I would say this middle case is the slim version of either Type F or G.

Case back of Ref. 3646 Type A, 1009498



This watch might look good at first glance but there are many inconsistencies. A movement or at least Cal. 616 bridges produced after 1956, combined with old parts to create the impression that this watch is from the 1930s. Other details that do not add up are the movement ring from a later 3646 and the middle case that looks like from 1944. The dodecagonal bezel bearing “Officine Panerai – Brevettato” engravings is a style that – in my opinion – was only introduced in the 1960’s.

Thanks for your interest.



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