Just an addition, I think the Maramu and some of the older designs had the prop shaft generator, which, given fair winds, produces a fair amount of electricity en route.
I agree though about extra fuel and peace of mind - our Santorin carries 400l and we took an extra 80l in Jerry cans in the liferaft locker. We hardly used any diesel at all on the Atlantic crossing and only needed the engine coming in to anchor. We have no experience of the longer Pacific passages.
Any other comments from folks with the prop shaft alternator?
Ocean Hobo SN96