In other news, batteries are bad for the environment. Not very often, for the average sailor, I admit, but once in a while you have to dispose of some toxic waste. Instead, I propose flywheels! You put a flywheel in a vacuum, suspend it with electromagnets, and spin it up. Much more efficient energy storage than batteries, much lower maintenance, and less harmful waste. For a small sailboat, I suspect some sort of gimbaling system would be in order, otherwise you'd lose a lot of energy to gyroscopic precession. Also not sure what sort of weight we're talking about.
Still, that would be a sustainable yacht project I'd like to see.
s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27