When 3BAM deployed in the Old Port on the Labour Day Weekend, I noticed that many of the people walking around the gun platform were just as interested in the No.7 Director, the device we would today refer to as an "aiming circle," as they were in the 25-pdr gun. I actually set it up for 3BAM on the second day that I showed up to shoot photos, and discovered that it was quite a bit harder to level than a modern one, lacking the the three leveling screws our modern instruments have. Leveling was done entirely through adjusting the legs. It's also graduated in degrees and minutes of angle, just like the No.7 Dial Sight, for those who were wondering.
Anyway, it generated a lot of interest, though people had no idea what it was for and would more often look into the lens rather than the eyepiece, then wonder why all they could see was a cam net and sky. Gilles and his crew were pretty busy just explaining the gun limber and gun tractor, It was time for me to set aside the photographer and slip into "old gunner" mode and help out.
So here I was, in my ubiquitous photographer's black civvies and grey fedora explaining to people what this curious device was and how it was used to orient a battery in what I insisted on calling the "center of arc." Well, that's what we call it today, but the concept didn't exist in the British or Canadian artillery in WWII. Guns weren't recorded on a grid bearing as they are today. They were recorded at "Zero" on a "Zero Line." Nor were the guns given bearings. Directional laying was given a "switch" from the zero line, and further bearing corrections were given as "more" or "less" so many degrees or minutes. There was more. Firing data was mainly generated in the observation post, not the CP in those days, and corrections were usually made on the Battery-Target line, not the Observer-Target line as they are today.
All this I discovered later through internet research well after I'd gone home for the day, having given folks explanations using terms that weren't used in 1943. In some ways it doesn't matter; a zero-line and a center of arc serve exactly the same purpose. What matters is that my interest was piqued and I embarked on a journey of discovery and re-discovery. As Will Durant observed, "Education is the progressive discovery of our ignorance, " and I had just become a little less ignorant. Next time my explanations will be more accurate.
Ubique!
Gary Menten
Photographer
