It's not ucommon to have AC installed to docks/piers/marinas. these are useful for lifts (capable of lifting up to 10k lbs), accessories (AC, refrigerators, microwaves for cabin cruisers).
Electric boats are more common in Europe, Correct Craft makes the 220e in its lineup this year.
Here in the US, I've never seen a slip with anything other than a 120v connection. And I'm pretty sure you'd pop circuits like crazy if more than a few boats on a dock tried to draw the full amperage.
It makes more sense in Europe where you already have 240v. But the marinas here just aren't set up for this.
Pontoon boat would not use the Ford crate motor from the article, they use 55-110lb thrust electric trolling motors.
Example: Minn Kota Pontoon Freshwater Electric-Steer Bow-Mount Trolling Motor with Digital Maximizer & PowerDrive Foot Control, 48" Shaft
Most folks don't use their boat all day each day so it can sit and charge for days between uses and often on a use you aren't going far, then you anchor and hang out.
