Viking Line's LNG-run cruise ferry is the world's first passenger ship to be equipped with a rotor sail thanks to which she'll be able to use wind as an auxiliary source of power for propulsion.

The sail, developed by the Finnish Norsepower, is 24 m high and has 4.0 m in diameter. The machinery takes advantage of the so-called Magnus effect - as the rotor is spinning, the passing air flows with a lower pressure on one side than on the opposite; the propulsion force created by this pressure difference drives the vessel forward.

The operations of the rotor sail are automated - the system will shut down in response to disadvantageous changes in the wind's direction or force.

According to Viking Line and Norsepower, emitting as much as 900t of CO2/year can be avoided in result of using the rotor sail.

The ferry line's newbuild, currently under construction in China and scheduled to set sail in 2020, will have two rotors mounted on her.

"This is a great day for us. As an Åland shipping company, we rely on the sea for our livelihood so it's of prime importance for us to promote the well-being of the marine sea. We want to pioneer the use of solutions that reduce the environmental load. Based in Finland, Norsepower has developed a world-class mechanical rotor sail solution that will reduce fuel consumption. We are proud of the fact that our Viking Grace will be the first passenger ship in the world to benefit from this innovative solution," Jan Hanses, CEO, Viking Line, said.

Tuomas Riski, CEO, Norsepower, added, "For Norsepower, it's an honour to be able to make the M/S Viking Grace even more environmentally-friendly by means of our novel rotor sail technology. The last traditional windjammers in the world were owned and operated by shipping companies based in Åland, so it's fitting that Åland-based Viking Line should be a forerunner in launching modern auxiliary sail technology. Viking Line and Norsepower's organisations have collaborated in an excellent manner in retrofitting the rotor sail solution on the Viking Grace, and the completion of this project is a great moment for all those involved."

Photo: Viking Line/Bo Strandén