Great Scott! Marty! To the Delorean! Hahahaha...that was great. And pardon my ignorance, but is the appeal primarily not spending money on gas? If so, do people spend that much on gas in their boats? Guess you could if you're not a 9-to-5er.
Great technology, but the batteries are still too far behind to make it practical except on the electric only lakes. I say for boats especially drop the electric idea and move to hydrogen engines. Do that a reasonably sized system to separate the needed fuel from the water you are in and no more worrying about range limitations(well unless there are reliability issues).https://www.youtube.com/watch?v=LOS3jpcv2V4