Data Processing for Ship Screw Propellers Measurements
A data acquisition system was developed for measuring standardised ship propeller’s parameters. The hardware consists of two linear and one rotary encoder, all sending the data to a counter/timer data acquisition board. The software is first aligning the different coordinates systems of the propeller and of the three encoders . Data processing is initially performed for compensating the effects of different encoders’ resolutions. There are then computed the blade profile’s length and the coordinates of the points belonging to the blades’ reference lines, together with the local pitch variations on each radius and blade, the mean pitch per blade and the mean pitch of the propeller. A discussion is made about choosing the most appropriate number of points where the local pitch is computed, thus providing useful data for estimating the best way for propeller’s overhauling.