Hi, Your comments are always most welcome
I have made up a stick which is the same length as our airdraft 6'1". We keep it on our roof and when we get close to a bridge that is suspect, we moor up just before the winding hole and we walk up to the offending bridge.
One of us (usually me) then walks on to the bridge and hangs the stick down from the bridge top on a line until it touches the water. The other person on the towpath can then see whether we are going to make it or not and we return to the boat and either proceed or turn around.
Its not perfect and you have to watch the boat trim if the water tank is low, but its better than getting to within a couple of feet of the bridge and then having to go astern (with boats behind you or in strong winds).
