Prop-rudder combination for energy savings

The companies say that rising fuel costs and competitive market conditions are making ship owners and charterers attach greater importance to efficient and fuel saving operation. With slow steaming and a number of fuel saving products, ship owners and operators are reducing operation and maintenance expenditure as much as possible. The energy saving package is intended to address this trend.

The package combines the advantages of an optimised, highly efficient fixed pitch propeller from MMG with an asymmetric Van der Velden leading edge rudder with a propulsion bulb and adapted hub caps. The package will be optimised according to the ship’s operational profile and the respective demands of fuel efficiency, good and effective manoeuvrability, minimising cavitation and vibration, and low maintenance. The propeller geometry and slip stream adapted rudder will be adapted to these needs, while a bulb with caps or fins is part of the solution.

The rudder is based on Van der Velden’s ART full spade design, with a modified profile above and below the centreline of the propeller so that that the effects of the rotation of the propeller slipstream are countered. This expands the cavitation-free rudder angle and reduces drag, increasing speed or improving fuel consumption, while the propeller design minimises tip cavitation. The Costa bulb, junction cap or boss cap fins prevent hub vortex losses and cavitation. The system is suitable for both newbuild and retrofit.