So CB is Chesapeake Bay
? Not citizens Band? Not the old dance place as in CBGB's? hmmm...practical max draft depth
? Well, freighters with up to 42' draft
make it up the ship channel, so I'd say that was the practical max draft if you are on a ship. Those same freighters have about 186' clearance at the center span of the main or west span of the Chesapeake Bay
Bridges. You did not specify what kind or type or size boat you were looking at so why not a freighter? They have masts too!. If you go up some rivers you will come to bridges with a bit less air draft, but for most practical purposes, any size mast
will do. I have to wonder why with such extensive information to the nth degree about Chesapeake Bay boating
so readily available online why such a question is posed here...."Bottom" line so to speak? If the "CB" is your prime area 5' is fine, 4.5 is of course better and 6' is acceptable. Same for the Bahamas
. As for air draft, like I said 186'..now if you wish to go under the secondary span of the bridges, the vertical clearance is 58', but don't take our word. Look on a chart!