When marine growth accumulates on a propeller’s surface or surface roughness increases due to aging, propeller efficiency lowers and fuel consumption increases. To lower fuel consumption, fuel-saving polishing, where propeller blades are polished to reduce blade roughness, is effective.
Various test records and data show how propeller surface roughness influences propeller efficiency. A comparison between a highly polished propeller with a roughness of 12 m Rz (approx. 3 μRa) and one finished with a rough grinder to a roughness of 50 μm Rz (approx.10 μRa) indicates a difference of approx. 3.5 % in efficiency and 1.7 rpm at equal horsepower.