We have followed the E-Ship 1 for the last four years. The ship is a Ro/Lo cargo ship owned by the world’s third-largest wind turbine manufacturer, Germany’s Enercon GmbH and is distinctive because it is fitted with four Flettner rotors. The rotors are vertical cylinders which spin and develop lift due to the Magnus effect as wind blows across them. So far, Enercon reports that they are observing roughly 25% fuel savings due to the rotor sails.

In December, the Finnish shipping line Bore installed a single rotor on the ro/ro M/V Estraden. The installation is an updated version of the Flettner rotor featuring advanced materials and a leading-edge control system designed and built by the Finnish marine engineering company Norsepower Oy Ltd.  The ship will be undergoing testing of the new rotor sail auxiliary over the next several months.

The basic design of the Flettner rotor has been around for over 90 years. Flettner applied for his patent on the design in 1922. The Flettner rotor ship Buckau set sail in 1925, first crossing the North Sea and then the Atlantic.