Performance of a Family of Surface Piercing Propellers

Experimental tests have been performed on a systematic series of surface piercing propellers with varied number of blades (4 and 5) and pitch ratio (from 0.8 to 1.4). Influence of depth of immersion and shaft inclination is discussed and results for variations in these parameters are presented. Regression equations are given describing the relationship of the thrust and torque coefficients for advance coefficients above the critical values. Influence on Weber number is briefly considered, confirming results of previous works. This work is the result of a research on the performances of surface piercing propellers undertaken by the University of Genoa and was partly developed as a doctoral thesis