Yeah, but did it have an induction cook top?
It is amazing that the only people and countries that are overly green (as opposed to sensibly green) are the "wealthy." To whit Fisker, Tesla, Biosphere, Solyandra, E10 and 15 fuel -- yada yada.
Where does China and India fit in on this scale? Both produce for their domestic markets more zero emission vehicles than the rest of the world.
Back to the topic at hand, there are two candidates with efficient enough hulls for solar assisted diesel-electric propulsion. On a displacement hull the math is rather simple, to increase speed by a factor of 2 requires an 8 fold increase in propulsion power. Take the WOT top speed of any boat and work backwards to find the power requirements at very slow speeds.
As I mentioned, the Chris White designed Buzzard's Bay power cat is one, and Larry Graf's (of Glacier Bay fame) Aspen C90 power proa is the other. On the Aspen C90, with the addition of just 1520 watts of solar, collecting an average of 5 hours per day at full output, could travel 66 nm for a 24 hour run without using any fuel or stored electrons. With the power of its Volvo-Penta 150 hp single engine can reach 20 kt at WOT, so 10 kt will only require 18.75 hp. To keep balance, weight and trim the same, this boat could be powered by an 80 Kg Steyr turbo diesel that produces 36 hp and would push the boat at 12 kt. The 500 lbs saved in engine weight reduction would be used for lithium batteries and solar panels.
For those that have no desire to cross oceans at the stately speed of just under 3 kt, (faster in reality because you would plan your passages as us sailors, using wind and ocean currents) with 36.4 Kw-hr of storage you could run at these speeds for given distances using the Aspen C90's hull efficient design. One of these distances might suit you for your cruising, if not, fire up the diesel.
16.3 nm @ 12.5 kt
26 nm @ 10 kt
40.6 nm @ 7.8 kt
65.1 nm @ 6.25 kt
104.1 nm @ 5 kt
162.4 nm @ 3.9 kt
258.2 nm @ 3.1 kt
415.5 nm @ 2.5 kt
With the 1520 watts of solar and sunny days, it will take 5 days on the hook to return under stored electrons.
I don't know about the rest of you, but if a brand new boat that can be purchased for $250K had the above capabilities, count me in. Since the Aspen C90 nicely equipped is $200K with the much more expensive 150 hp Volvo, I don't see any problem coming in for $250K.
There is a huge difference when your beam to length ratio is 10 or 12 to 1 vs. the 2.5 or 3 to 1 of a typical trawler displacement hull.
(That;s my story and I'm sticking to it!)
