Nuclear vessel 'could be floating charging station for electric cruise ships' (world-nuclear-news.org)

Power storage feels like a complete non-starter, without radical breakthroughs. It'd be vaguely interesting to run the numbers & see what % of a ship would need to be hydrogen gas storage, perhaps. Whether that is for a single leg of a jaunt makes a big difference. I wonder how often cruise ships tend to refuel.

It could make ammonia from air and water. Current engines can be modified to run on ammonia.

Fueling can be done in an hour.