I wonder how viable an autonomous single-container electric cargo ship would be, instead of massive ships you could have thousands of tiny ones. With automated loading/unloading it could massively simplify logistics

A solar panel covering the ship and one of those flaps to generate power from wind with a EV-scale battery could be enough for containers moving light non-time-sensitive stuff. Probably wouldn't be able to run the engine at night for long though.

Heck throw some wheels at it and fast charging at docks and it could even potentially drive down the road as a truck directly from sea.

While I don't have any deep foundational knowledge, I do know that:

- the energy required for moving in a fluid grows sub-linear with the vessel's volume

- larger motors tend to be more efficient

- your autonomous swarm will be a gigantic waste of steel and batteries.

Not to mention the problems around the autonomous part, without which you'd also have a huge waste of manpower.

See also https://engineering.stackexchange.com/questions/38252/why-on... for some points by people I assume know a bit more than me.

My dream variant of this notion is a waveglider. Super efficient, if a little slower.

Bonus points for adding a big scoop, to slurp up trash and filter out microplastics.

That sounds like a nightmare in port. Instead of one ship, now you have thousands arriving one after another.