Experimental Study on the Propulsive Performance of Icebreaker PLH "SOYA"

Abstract

To obtain a full understanding of icebreaker propulsive performance, full-scale and model experiments in ice were carried out for the icebreaker PLH "SOYA". A full-scale ice trial was made in February 1997 in the Sea of Okhotsk. A speed trial was carried out with a stopping and a bollard-pull test. Shaft thrust and torque were measured using strain gauges mounted to the propeller shaft. In this paper the accuracy of full-scale thrust measurement was investigated from various aspects. Firstly, the cross coupling effect of the shaft torsional strains to the compressive strains were evaluated. Secondly, in order to improve the accuracy of thrust measurement, thrust at zero CPP blade angle in a stopping test was used as its zero-level. Thirdly, repeatability of the thrust measurement was examined using the data of bollard-pull tests. The scatter range of thrust was found withwin 20kN. Finally, thrust data was compared with the medel-prediction result. Model resistance tests in ice were carried out at the Ice Model Basin of the Ship Research Institute. The regression model for the model resistance in ice was presented. The thrust deduction factor was estimated from the model overload test in open water. A fairly good agreement was obtained between measured and predicted thrust.