We do. They just don't look like sails. This is a Maersk ship. https://en.wikipedia.org/wiki/Rotor_ship#/media/File:Norsepower_rotor_sails_modern_version_of_fl

We do. They just don't look like sails. This is a Maersk ship. https://en.wikipedia.org/wiki/Rotor_ship#/media/File:Norsepower_rotor_sails_modern_version_of_flettner_rotor.jpg https://en.wikipedia.org/wiki/Rotor_ship#/media/File:Norsepo...