Sure, you're not burning a ton of fuel a minute plowing through dolphins and kelp, but you still need to generate power to operate all of the on-board facilities such as electricity, plumbing, elevators, etc. Would the city allow an entrepreneur to run a fat power cable onto a sitting ship - leaving aside political implications of a big honkin' vessel blocking the ocean view, are there even any regulations written for it?

Based only on what I've read of jwz just attempting to put a door in a nightclub wall, it seems that a hostile takeover over San Francisco, followed by some summary executions of most of the city government and a formal secession from the United States of America would be easier.