Viking Line installed a Norsepower rotor sail unit on its cruise ferry Viking Grace, making her the only working passenger ship in the world with modernized Flettner rotor.
According to Viking, the 80-foot-tall rotor would allow for the Grace ferry to save up to 900 tonnes of fuel per year on her run between Turku and Stockholm.
A newbuild Viking Line ferry currently under construction in China will receive a couple of the Norsepower rotors.