Wartsila, the Finnish company best known for its marine diesel engines, has unveiled a design for a large cruise ferry that uses lng to power its main engines and Flettner rotors that use wind to provide additional power. These use the so called Magnus effect, which is a force acting on a spinning body in a moving airstream, which acts perpendicularly to the direction of the airstream.
The 58,000 gross ton vessel has two electric pods on both sides of the centreline plus a fixed propeller in the centre, which is mechanically driven,, says Oskar Levader, head of conceptual design at Wartsila Ship Design says. “This cruise ferry concept designed by Wartsila has been designed to give both the highest level of efficiency and lowest emissions while also providing passengers with top-class experiences,” Levander writes in the company’s TwentyFour7 stakeholder magazine.
“Not only does this arrangement result in significantly lower emissions, it also allows for some reductions in energy demand on board. The low temperature lng can be used for cooling the air conditioning systems, reducing the need to run compressors. There is no requirement for HFO tank or trace heating,” he continued.
In addition, three Flettner rotors in the stern that also act as funnel uptakes and one forward that doubles as mast utilise wind energy to generate additional thrust. These can generate more lift than conventional sails and can work at quite small angles of attack, i.e. the angle between sail and direction of the wind.
An illustration in the magazine shows the vessel with red hull, used by e.g. the Finnish cruise ferry operator Viking Line, although it does not carry this company's logo. Viking Line is considering to replace its ageing fleet with new ships, but has stated that an order is not imminent. .