If a long un capsizeable boat with hot swappable battery modules had epoxied panels and electric power then it could autonomously go out to a location, fill up, and come back to base.

We could fill 10% of the ocean with solar vehicles like this while using them for a futristic train hop.

I think such a vehicle though should be capturing hydrogen though because the Speed at which they store isnt an issue at such a scale: off loading hydrogen stored in magnesium hydride pellet tanks would be most ideal.

This way, nuclear will have to put up or shut up