They don't work like a traditional sail but "rotor sails" are a fairly recent innovation and seem interesting: https://en.wikipedia.org/wiki/Rotor_ship https://

They don't work like a traditional sail but "rotor sails" are a fairly recent innovation and seem interesting: https://en.wikipedia.org/wiki/Rotor_ship https://en.wikipedia.org/wiki/Rotor_ship I've seen articles here and there about adding them to tankers to increase fuel efficiency.