I’m well aware that there’s usually a few extra inches added on for contingency, which is good especially as some of the boards seem to lean over more each time I pass them. On the southern broads they appear to be more accurate. The reason I’m asking is I went under Beccles bridge last night, and I took extra precaution of taking screen down as it was going to be tight, when I went through I was shocked, it wasn’t just tight, there’s no way my screen would’ve gone under. So I have a suspicion the actual clearance at Beccles oldroad bridge may be lower than the board suggests
I could be wrong of course, when it’s tight the bridge above your head always looks really close.
Anyway, I was just curious about calibration. I often see the rangers washing signs at Breydon but never see them measuring them, and never seen a ranger checking anywhere else.
I will bring my laser from work next weekend and double check the height of my boat.