Re: Petit Bois/Dauphin Island Pass and Perdido Pass
After you enter the pass, and before the bridge, the channel divides into two marked channels to go under the bridge. The east channel under the bridge is the one I take because of the bridge clearance. You need to stay to the west side of that east channel as you go under the bridge. You are correct that the east side of the pass gets very shallow.
I have a video as I am approaching and go under the bridge with the current which I can email to you if you want.
You do know that the Ono Island Bridge has a low clearance....I think about 24 feet. You will have to go around the Island and back to the Crab Trap unless you can get under the bridge.