MoparDave, my old job also required us to work at heights above flowing water, and it was never a thing that worried me. Also, I was quite happy to work high on a ladder or in a harness dangling off a bridge. However, with age, I've developed what seems to me a quite rational fear of working on high ladders. I suspect it's because I'm aware that my balance, reaction time and coordination are probably not what they were.