A new age of sail begins

In 1926 an unusual vessel arrived in New York after crossing the Atlantic. This was a converted sailing ship renamed Baden-Baden. Its two masts had been torn down and a pair of 15-metre-high revolving cylinders were mounted on its deck instead. Known as Flettner rotors, after Anton Flettner, their German inventor, the rotors worked like sails. Not only were they extremely efficient, allowing the vessel to consume less than half the fuel an oil-powered ship of a similar size would use, they also let the craft tack closer to an oncoming wind than its original canvas rigging allowed. The rotors were hailed as a great achievement at the time (praised by Albert Einstein, among others) before cheap oil caused interest to wane.