He had plans to supply all his power needs without fossil during his around the world thing. I don't know how he did on that front but your method proves what we know;. the smaller the boat/house, the easier it is to achieve full self sufficiency. Your approach is conservation first.

Boats keep getting bigger(just like houses) so the challenge gets tougher. Sailboats are the only hope of ever being a self sufficient craft. Funny that they used to be, but today it's become more and more difficult. They're complicated tools.

The only incentive for higher energy saving products on boats, I can imagine, would be from the government for cleaner water/air. Long shot...