Share this article Finnish technology firm Norsepower has completed testing of one of its “Rotor Sails” onboard the Viking Grace. Installed in 2018, the MS Viking Grace was the first passenger vessel to be fitted with the technology as a means of reducing vessel’s environmental impact by harnessing the power of the wind. Norsepower’s Rotor Sail solution is the first third-party verified and fully commercialized mechanical sail. It is a modernized version of a Flettner rotor, a spinning cylinder that uses the Magnus effect to harness wind power to propel a ship. The testing period for the Viking Grace was completed in April and the results have been independently validated by ABB, Chalmers University, and NAPA, in addition to Norsepower’s own analysis. The results confirmed that the Rotor Sail reduces power consumption between 207-315 kW equalling 231-315 tons of fuel per year, which was well in-line with original target of the project, according to Norsepower.