The grand old age of sail could be on the upswing again in the maritime industry, but not in quite the same way as in the age of Clipper ships. New devices called “rotor sails” use the same principles as their canvas cousins, but apply them in a different way. Spinning columns on ship decks generate the same kind of lift as traditional sails. They save fuel and are already in use on some cargo ships, such as the Maersk ship pictured here.