A four-bladed propeller model has been tested in a water tunnel with a flow regulator. Cavitation erosion of the aluminum alloy blades was caused by simulating the wake pattern behind a single screw ship in the test section of the tunnel. The relationship between the rate of weight loss and the time of exposure to cavitation was measured for each blade individually. Comparative tests, using the same material, have been carried out in a rotating disk apparatus and a magnetostriction oscillator. The erosion rates of the propeller model and of the specimens tested in the rotating disk apparatus show a similar dependence on time during the incubation, acceleration, and deceleration period. A steady-state period does not occur. The erosion rates of the specimens tested in the magnetostriction oscillator show a considerably different dependence on time. The mean erosion intensity of the test devices is 2.5 to 3 times larger than with the propeller model, based on the actual time of exposure to cavitation.