Charts,
guidebooks, and Active Sam will give you the exact bridge heights. In the macro sense, entering a
commercial harbor from the ocean will generally be issue free, but CHECK
charts. I live in Charleston--open access to/from ocean via
shipping channel. Nothin in the way.
ICW runs through the harbor going N-S, and in either direction on that you will come to an abrupt halt in front of a 65' bridge.
You'll have to go outside Hatteras. Wait for a good
weather window and enjoy. Day and a half to Norfolk or less if you ride the edge of the stream. Entering the Chesapeake at Norfolk, same principle. Entry from the
Chesapeake Bay to most harbors is fine. Lots to see. Go to the top of the Bay and out to the Delaware River/Bay via C&D
Canal. No worries. You will have to go around Cape May and enter from the Atlantic Inlet. Bridges on Cape May
Canal too low. If you cross from Cape May to Block Island and north, it is open ocean. If you go up the Jersey shore, the major inlets can be entered with your
mast from the ocean.