RADIOMIR PANERAI 3646
"brownie"
HISTORY
S.L.C. "Maiale" in action
In 1936, under the fascist regime, Italy was approaching to enter WWII. One of the strongest italian armed forces was the Navy.
The Navy commandos were bound to operate in the harshest environment and were in need of specific equipment. Most of this equipment had been supplied by Officine Panerai for years: torches, depth gauges, compasses were produced by OP for the italian Navy since the beginning of the XX century.
When the Command of the 1st Submarine Group requested the study and creation of a special underwater luminous watch, it was natural for the italian army to ask Panerai to develop this special watch given their expertise in luminous tools and their commercial links to the swiss watch manufacturers (the Orologeria Svizzera was the oldest italian distributor of swiss watches such as Patek Philippe, Rolex and so on).
The watch that Giuseppe Panerai presented was the apex of innovation for that time: the reference 3646.
The watch consisted in a large 47 mm cushion shaped case with screw-in caseback, a screw-in winding crown and strap attachments made of metal rods welded to the case (the wire lugs).
Crown and case back were marked Rolex, so was the movement which was a manual winding 15 jewels movement based on a Cortebert ebauche.
The crystal was made of Perspex (plexiglass), the same material used on Panerai compasses and depth gauges. The strap was made of greased leather and it was long enough to be worn over the waterproof clothing worn by the commandos.
The first prototype presented by Panerai in 1936 featured an unbranded black dial with painted roman numerals in the top half, a triangle at 12 and arabic numerals on the bottom half. This is currently referred to as the Cali dial.
As soon as the regular production started, the dial was changed to a special dial developed in Florence directly by Panerai. The arabic and roman numerals were replaced by four large arabic numerals at the cardinal points and batons markers between them.
Numerals and markers were not painted, they were instead cut through the upper dial plate. Under the upper plate sat a plastic disc with the numerals and markers in relief. The disc was filled with the radium luminous paste and sealed with a bottom plate.
This kind of constrution allowed for an unprecedented high readability of the dial in dark environments.
The RADIOMIR PANERAI inscription was present only in some of the produced watches, a sterile dial was considered more suitable for some special operations in order to avoid the risk of the factory being identified and sabotaged.
This watch became a regular equipment of the X Flottiglia M.A.S ("Motobarca Armata Silurante" - a motor torpedo boat) and its Gruppo Gamma's frogmen. It was used in a number of military missions, especially sabotage missions, the most famous being the sinking of the HMS Valiant and HMS Queen Elizabeth in the port of Alexandria, Egypt in 1941.
HMS Queen Elizabeth
So much for the fascinating history of this watch, credit for most of the informations above goes to the books "Legendary watches" and "Panerai Historia" by Giampiero Negretti, they are available for sale and not excessively expensive.
Sorry if I've been a bit verbose, I'm sure many of you already knew this story better than me, but history and watch design are so bound together in vintage Panerais that I felt the need to "frame" the historical moment behind this watch before going on with the pictorial.
THE BUILD
I'll try to keep it short on the build itself, this is not a planned build, more of something that came out naturally from a few parts I had gathered.
Midcase is River's, aged by me, shape softened and satin finished with 600 grit sandpaper.
When working on the case I managed to detach one of the wire lugs (breaking stuff is my real hobby you know
). This was a problem since I don't know how to solder... Luckily a great HF member named Sjever came to the rescue and offered to repair it for me, he even solder the crown area... Thanks Sjef! 
Bezel is mirror polished by me, maker is unknown. I think Athaya but I am not sure as it came on a complete watch I bought m2m and disassembled. Plexi looks to be a high-dome flat-top Sternkreuz.
Unexpectedly caseback required a bit more work. Originally it was roughly polished, but I was not satisfied with the look so at first I decided to mirror polish it.
Then, once the work was done I decided I wanted to try a radial brushing. I went McGyver style and, after some trial and error I managed to mount firmly enough the CB on the dremel and hand brush it. I felt like a "real" craftsman and everything considered I'm pretty satisfied with the result, besides I learnt something new
Under the close CB an a6497, it's cheap and it's reliable. I don't know if it's the 3646 case or the different movement, but tbh building around a 6497 was a pleasure after a couple of builds based on molnija. The movement was perfectly tight inside the movement ring and everything fitted nicely almost immediately.
Dial is Bigwaved's, stunning work as usual. So nice it can make even my builds look decent
Hands are aged by me. Btw, the missing lume on the minute hand was not removed purposedly...
Finally the strap is from Green straps, it came on a black_shark build. Watch is gone, but luckily the strap remained. I can't recommend this guy enough, I have three of his straps and they are all top notch leather and craft, vintage looking without excessive ageing and super comfortable.
Few more pics:
That's all for now, hope you guys enjoyed the read and the pics. Next project is coming along already, see ya soon!
