I don’t see why you couldn’t get traditional speeds doing square rigs on a repurposed container ship, but maneuvering would be hard. I don’t know much about tall ship design, but I think they have to be able to turn very well to really tack with the wind.

Yeah, turning would be a massive challenge, and forget trying to sail upwind. But, the size of the ship would make them really stable, so they might be able to get sails up into winds that are more predictable and steady. On the other hand, they would require a massive keel, and that would limit them to really deep waters. Maybe in a sail-punk scenario you'd see trans-continental sailing ships being offloaded at offshore platforms, and smaller ships would then shuttle the goods to the mainland.

I still really want us to go in for nuclear cargo ships though. The NS Savannah is so cool. I’ve gotten to tour her a couple times in Baltimore. They want to turn her into a public museum ship with a reactor mock-up you can walk into, but need a few million in funding to properly decommission the real one.

Yeah, I understand the reluctance to have a nuclear reactor on a ship -- on anything that moves really. But, when you need megawatts of power to move something, you really have to think about the safety of the reactor vs. the fact that pollution from petroleum-based ships actually does kill people too, just in a much less accountable way. The Russians have a nuclear-powered icebreaker, I think. If ships are going to keep getting bigger and bigger, it makes sense to me that eventually more than just military ships will have reactors. Maybe we'll have to wait for the climate catastrophe to get worse, or for reactors to be less feared.