Chevrolet41
My impression is that the white line was added post-war.
The white line was NOT for aiming the mortar at night - for that you had the night aiming lamp - but for aligning the base plate with the 'zero line'.
The section commander would decide where to site the mortar/s and would plant a small flag. He would then establish the direction of the target from the flag, and an aiming post would be planted away from the site. So the imaginary line flag - post - target would be the 'zero line'.
The base plate would then be placed close to the flag, with the white line in line with the flag and the post i.e. on the 'zero line'. The flag was then removed.
The white line was offset to be in line with the sight, not the barrel, as you aim with the sight! The offset would make no difference at the target....you would not be sniping with a 3" Mortar!
__________________
George Cross Island
|