Yes I would say an air draft of 63 feet would reguire every bridge except the I-10 span at the industrial canal to open. I beleive it has a 100+ foot vertical clearence. Stepping the mast would be an extreme way around that requirement, but is a posibility.

Can you get under the I-10 single span (a.k.a. twin span) at slidell? I seem to recall a 55 ft clearence there. Just curious.

Let us know how your trip goes.