Volvo Penta’s highly effective three-blade propeller has been available for several years for boats with engines up to 60 horsepower. However, for larger sailboats with more powerful engines, the alternatives have been a fixed propeller, or one of the more complicated and more expensive variable-pitch versions.
With its new four-blade folding propeller, Volvo Penta is now offering a highly attractive propeller alternative for engines up to 120 horsepower. “The new folding propeller provides owners of sailboats from about 40 feet and longer the possibility to select a propeller that offers minimal drag under sail combined with effective propulsion when the boat is cruising on the engine. Compared with a fixed propeller, the four-blade model can offer up to 1.5 knots higher speed under sail, according to Bror Gustavsson, Product Manager at Volvo Penta.
Volvo Penta’s three-blade folding propeller quickly set the standard when it was launched six years ago. As a result of the efficient blades, propulsion fully matches the power delivered by a fixed propeller and is about 50 percent better in reverse than a two-blade folding propeller. Tests conducted with the four-blade propeller indicate that the results will be at least as good.
The propeller blades have a unique, elliptical (high skew) shape and the propeller is patented by Volvo Penta. The design originated with submarines, which of course seek the smoothest, quietest and most vibration-free operation possible. The water slides along the propeller blades and is released smoothly from the tip, which ensures effective operation with minimal vibrations.
The four-blade folding propeller is available for S-drives and traditional shaft installation. The hub and the blades are sold separately, which offers a great number of various combinations and helps ensure that each boat is equipped with exactly the right propeller. The hub fits 25-40 mm shaft diameters and corresponding sizes in inches. The blades are available in several sizes and with different pitches as well as for left and right hand rotation.
The material is a specially developed bronze alloy that is highly corrosion resistant. Volvo Penta’s four-blade folding propeller is being launched in November 2002 and will be available for delivery in the spring of 2003.
For further information please contact AB Volvo Penta, Bror Gustavsson, phone number +46 31 3221606.