Estimation of stopping ability of full-scale ship using free-running model

Abstract

The authors discuss how to estimate full-scale stopping ability of ships using free-running model test equipped with an auxiliary thruster. Theoretical analysis based on a modular mathematical model clarified the similarity of three-degree-of-freedom stopping manoeuvre cannot be ensured by the use of the auxiliary thruster. The authors, however, propose J and speed correction, JSC, ensuring the equality of propeller advance ratio J and the similarity to full-scale of speed response of free-running model ship during stopping manoeuvre. JSC is a control method of free-running model ship equipped with an auxiliary thruster for estimating stopping ability of full-scale ship from the viewpoint of safety. Numerical simulation confirmed JSC gives safe side estimates of stopping ability in terms of track reach and stopping time with acceptable margin, which proved the advantage of JSC comparing with possible other control methods. Tank test data demonstrate how JSC works well.