Yeah, and nuclear, which is deployed at huge scale in seafaring vessels in the Navy. Merchant nuclear propulsion had an early start and is likely to see a revival imho.
A commercial nuclear-powered cargo ship would have to be refueled on the same time scale as a commercial MOX or LEU reactor, likely raising costs quite a bit over any other fuel. Plus, what harbor would allow commercial nuclear reactors, given the costs of catastrophic failure, without ridiculously expensive levels of security and safeguards?
That said, one interesting approach is to use ocean-faring nuclear-powered tugs that basically stay out in international water and hand off massive container barges to little fossil fueled short-haul ones that can take it in to port where people are afraid of nuclear fission but don't care about air pollution or climate change.
As for refueling, it's true that submarines don't need to refuel for 30 years. But there's a lot more room on a container ship, so you can make a big core and run it at less than full power. This way you can get it to only need refueling every 5 years or so with low-enriched uranium. Not bad.
Nuclear tugs: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1559-3584....
These ports already handle tens of thousands of tons of explosives - the blast in Beirut wa over 1 Kt of TNR equivalent, and all that ammonium nitrate arrived on a single ship. It was basically a small nuclear detonation.
I'd love to see it, but I'm a bit pessimistic about the political viability of a significant revival of civilian nuclear ships.