Beobachtungsurhen

I made mention the other week of WW2-era aviator watches, the most classical and pure examples being those used by the Germans and called Beobachtungsurhen. I linked out before to one short description, but here is a fuller overview from an old watch review on Equation of Time by Mort Schwartz (now archived on PMWF):

The Beogachtungsuhr model, often referred to as the “B-Uhr,” used a design specified for the German Luftwaffe and was produced by IWC, Lacher & Co. (Laco), Stowa, A. Lange, and Gerhard Wempe. A standard common movement was not used by the contractors. Stowa, for example, utilized a movement based on Unitas that included a swan neck regulator. Lacher used a Durowe cal. D5 movement, while Lange used its own cal. 48/1 movement and Wempe used a Thommen (Waldenburg) cal. 31 movement. And all of these watches were manual wind.

The translation of the term, Beogachtungsuhr, strictly, is “Observer’s” or “Observation Watch,” but many collectors agree that a more descriptive label is “Navigator’s Watch,” and I have seen some mention of it as a bombardier’s watch. Interestingly, the watch was not issued to navigators and possibly to other members of the air crew, as part of their regular uniforms and equipment allotment, but, instead, “loaned” to them just before they went out on a mission. The watch then had to be returned if they returned. One can wonder how the watches faired in plane crashes. The watches were fitted with extra long leather straps because they were often strapped over the sleeves of leather jackets just as has been done more recently for the same kind of reason with some of the watches provided to astronauts. They, of course, would strap their watches over the bulky sleeve of a space suit.

The model most commonly referred to in my research is the mammoth IWC “Large 52 S.C. Calibre Pilot’s Watch.” S.C. is the abbreviation for “second au centre,” central seconds hand, or what we usually term a sweep seconds hand. I have never seen the actual model, but the literature indicates that the size of this watch was about 55mm, which is the same size as the watches produced by the other four suppliers. IWC took its manual wind Cal. 52 pocket watch movement, with 16 jewels and 18,000 beats per hour, and a swan neck regulator, to produce this wristwatch. As just indicated, the conversion also included adding a center sweep seconds hand.

Other features, as with the ones produced by the other four suppliers, included an extra large crown to facilitate setting time and winding and hacking. IWC added an inner plate to shield the movement against magnetic fields. The history of this model does not end here. This same movement was used in wrist watches made for the British forces, and I have read that they were used by the British navy as a deck watch. The models made for British use were designated with “Mark”, and we see that same label used in early and current production runs of IWC, such as the Mark X and XV. Jaeger-LeCoultre also produced these or similar watches for the British armed forces.