It's an interesting idea, Bilojax. And I am not trying to pick it apart, but I need to ask a question...

50-100 MPG in a boat?

I need some of the small fishing boaters here to educate me. The last boat I had ran a 200hp Merc/Mariner and pulled down nearly 6 gallons/HOUR. But that was with a decent size boat with a Deep-V hull. I know the smaller and shallower draft boats have to be a lot more effecient than that.

But I still think range has to be a factor if you bug out via small outboard doesnt it?