Estimated Manoeuvrability of T. S. Wakashio-maru-I : Wind Tunnel Test and Rudder Open Test

Abstract

Some model tests were carried out to estimate the manoeuvrability of the new training ship Wakashio-maru IV, in which a controllable pitch propeller, bow and stern thrusters and a Schilling rudder were equipped. This paper mainly deals with experimental results of the wind tunnel test, the rudder open test and flow visualizations around the rudder. The results are as follows ; (1) Wind moment coefficients shows the difference between Wakashio-maru IV and III caused by their differences on sizes and types. (2) Wind forces of Wakashio-maru IV at 10m/s wind velocity is estimated as 2 times of III. (3) Normal force coefficients of the Schilling rudder shows better performances than the ordinary rudder at all rudder angles, which is from -70 deg. to +70 deg.. This increment of normal force coefficients is caused by end-plates effects. (4) The Schilling rudder decreases stall effects on normal force coefficients. This decrement is caused by effects based on the shape of rudder section. These results will be important information on ship handling for the navigators of the new ship.