Norsepower rotor sail: positive results for Viking Grace

Norsepower’s rotor sail – which was retrofitted to Viking Line’s Viking Grace this April – is set to save 300 tonnes of fuel annually. And Norsepower chief executive Tuomas Riski told MP at SMM “First experiences show that when there have been favourable sailing conditions with high wind from the beam, the ship has sailed faster than before.”

Developed by the Finnish company Norsepower, the rotor sail solution on Viking Grace – the first passenger ship to use a rotor sail – allows the cruise ferry to use wind power, thereby reducing the main engine load and saving around 5% annually a year on fuel.

Viking Line will also use wind propulsion in the company’s new vessel, which is due to be operational in 2020. Built in China, the passenger ship will be equipped with two mechanical rotor sails supplied by Norsepower, thus doubling the wind power potential to 600 tonnes.

Mr Riski said “It was good for the project to start with one rotor sail [on Viking Grace], as it allowed us to gain experience. We estimate that the fuel savings will be double on the new vessel.”

He said the technology “fitted well” with cruise ferries. “It saves fuel and it is good for their image to be environmentally friendly – this is the first technology to be so highly visible as an energy-saving device.”

While the company has not won a cruise contract yet, it is feasible for this sector too.

The cylindrical rotor sail installed on Viking Grace is 24 m in height and 4 m in diameter and uses the Magnus effect for propulsion. Viking Line explained in April “As the rotor is spinning, the passing air will flow with a lower pressure on one side than the opposite side. The propulsion force created by this pressure difference will drive the vessel forward. The rotor sail operation is automated, and the system will shut down in response to any disadvantageous changes in the direction or force of the wind.”