I admit to knowing nothing about real estate, and even less about ocean liners, but it seems that an ocean liner - even at sub-market rates - would be ridiculously expensive to buy, and then merely ludicrously expensive to operate.

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.

Why can't the ship generate its own power? Is a power plant can do it, so can a ship - it's large enough to be able to make the generator efficient enough. Load it up with LNG every one in a while - LNG is transported by sea all the time anyway.

If you plan ahead you can pipe the LNG throughout the ship for cooking, and maybe even heating.

It can absolutely generate its own power. But then you have to pay to ship a whole lot of diesel onto your ship. I'm betting that the liner's efficiency is a heck of a lot less than a local power plant's, since I assume that a line is optimized to move a screw through water, with electric power being a lower priority.

You could also build a better power plant on the ship, but that's not free, either.

Modern vessels use electric motors powered by a generator to move the screw anyway.