If you thought the ungainly looking rotor sail system, an invention from the early 20th Century, was gone forever, you were wrong.
Finnish wind propulsion company Norsepower Oy has announced it is to install rotor sails on board the already virtuously ‘green’ LNG/hybrid fuelled ferry Viking Grace 57,565,’13 of Viking Line. The Norsepower Rotor Sail is a modernised version of the Flettner rotor; a spinning cylinder that uses the Magnus effect to harness wind power to propel a ship. It is fully automated and senses whenever the wind is strong enough to deliver fuel savings, at which point the rotors start automatically.
Operating between Turku and Stockholm Viking Grace is one of the most environmentally-friendly ships in the world delivered at the former STX Turku shipyard with engines, propellers and bow thrusters from Wärtsilä and equipped to run on traditional heavy fuel oil, diesel or liquefied natural gas (LNG). Rotor sail technology should further reduce emissions and deliver annual carbon savings of around 900 tonnes, equivalent to 300 tonnes of LNG fuel.
Norsepower will fit one medium-sized rotor unit 24ms high by 4ms diameter, with installation in early 2018 when she will be the first-ever hybrid ship to operate on a combination of LNG and wind power. The technology is already in use on Bore Line’s ro-ro freighter Estraden which has achieved a 6.1% reduction in fuel consumption through its use.