ImPortant weaknesses
I don't know any details (I was AF), but I am aware that CB instaport capabilities are a strategic asset. I don't know how far it goes, but for the US, at least, we can make a sizable port (or three) very rapidly.
But it really all depends on what route you want to take. Consider a 10MT nuke in the shallows, or a 5OMT a bit further out. I know that our major ports are actively searching for those.
I would also assume that when things get hot enough, that the PAs will get aggressive about requiring tugs and even "safeing" engines once a ship gets close enough--imagine a coal ship shearing a bunch of piers.
I remember reading, what, thirty years ago? about computer controlled pumping systems on oil tankers. Trivial to overload the center and crack it up.