A second consideration is if you have neighbours. People working under canvas
or inside on a windy day might not like the noise
of your wind gen considerably closer than would be the case at anchor
, and if it's REALLY windy, they might not like what a snapped off blade moving with the impetus of several thousand RPM
could do to their decks or to them.
A better choice is a firmly lashed down 10W solar
panel to keep the batteries topped off. Little else is needed if the boat is otherwise shut down. I don't know if cats come with garboard plugs to let the rainwater out, should rainwater get in.