It wouldn’t work. The energy you’d use to spin up the generators is energy that could have been more efficiently propelling the boat. Regenerative braking only works on electric cars/hybrids while they are already slowing down. Pepetual motion and all that.
But yeah, covering the decks with solar panels would probably help, but you probably aren’t getting a boat on-plane pulling a skiier too easily. The only thing I can think of that could work reasonably well would be to start with a lightweight outboard hull, and replace gas engine with the biggest electric motor you can fit under the cowling. I’m thinking wherever you put it (outboard or I/O), the motor out of a crashed prius could work. Then you just need to get a lot of batteries.