Eco Motor Boat - Is it Possible?

A reader forwarded us the following question from Thrifty Fun: "I am moving down near the water and I would like to buy a boat, ideally a motor boat. I was wondering if there is an eco-friendly way to go about this. Are their eco-friendly boats with motors? Any info or tips would be appreciated." Since nobody has answered the question over there, we figured that we'd try to answer it over here. Unfortunately, we're more of the kayak type than the motor-boat type, so we're asking our readers for help. We figure that with a diesel boat, biodiesel would be the way to go, like in this case, but we think that only fairly big boats have diesel engines (but we could be wrong about that) so it's probably not very helpful.We also doubt that unmodified gasoline boat engines can run on a mix that is high in ethanol, and besides, the eco-benefits of ethanol are variable depending on the source (right now most of it comes from industrial-agriculture corn - it would be better if it came from waste cellulose), so that's probably not very helpful either.

Electric motors is what we thought of next, but we've only ever seen small ones that were used with very small boats or inflatable zodiac-style boats.

Windsailing or any kind of boat that moves most of the time with wind-power (usually with a backup engine for when the wind dies down) is another possibility. That would probably be the best choice short of going for a kayak or canoe.

So dear readers, what do you think? Is it possible to have an eco-friendly boat with a motor?

Thanks to Dawn or Teri (we don't know which one - the email had both names) for emailing us this question.

::Question At Thrifty Fun