FINNMARKEN Twin Efficiency Rudder installation

While a number of this year?s selection of notable ships are included principally for their pioneering use of podded propulsion, this revolutionary drive is not the only method shipowners and equipment manufacturers are pursuing to try and improve and increase operational efficiency.

OVDS, for example, opted to install two Efficiency Rudders from Wärtsilä Propulsion behind twin cp propellers on its ship Finnmarken, which Norwegian builder Kleven Verft delivered in April 2002. The ship, which operates in Norway?s coastal Hurtigruten service, is the first twin-screw vessel to have the equipment.

“So far operational efficiency is as we expected,” says Per Harald Ottestad, technical director of OVDS. “It is quite a complicated engine room on this ship and it takes some time to optimise configurations.”

The ship has cp propellers and a concycle shaft generator that operates on flexible revolution of the engine, within certain limits. This, says Ottestad, gives considerable scope to further optimise the shaft generator to the propeller hub to gain more fuel efficiency.

Specific tests to confirm the manufacturer?s claims about the rudders have not yet been possible due to a small problem with the clutch on one of the reduction gears, he says. This problem is scheduled for repair in January.

Finnmarken featured in the June 2002 issue of The Motor Ship.