SCALE EFFECT ON PROPULSIVE PERFORMANCE OF A FULL SHIP

In 1972, the propulsive performance of a thin ship was calculated, without the use of experimental data, in accordance with a theory developed a few years earlier by the second-named Author; the ship was assumed to consist of a hull, an infinitely-bladed propeller, and a rudder. In the present paper, the Authors (of Kyushu University, Japan) propose a theoretical method for calculating the propulsive performance of a ship or model of full form with an infinitely-bladed propeller (but without rudder). The method assumes that the hull resistance and the wake distribution at the propeller disc are known beforehand for a geosim model. Calculations, using this method, are carried out for three models (of 4, 8, and 12 m length b.p.) and for the full-scale ship (an ore carrier of 302 m length b.p.) in order to study the scale effect on propulsive performance. The results are presented in some detail and are compared with those from tank experiments and sea trials; several conclusions are drawn. Order from: BSRA as No. 47,702.