Stopping Test Method for Free-Running Model Ship Equipped With Auxiliary Thruster

Abstract

The authors report how to estimate stopping ability of full-scale ships using free-running model equipped with an auxiliary thruster. Theoretical analysis based on a modular mathematical model clarifies the similarity of three-degree-of-freedom stopping manoeuvre of a model ship to full-scale cannot be ensured by the use of auxiliary thruster. The authors, however, propose JSC, propeller advance ratio J and speed correction, ensuring the equality of J and the similarity of speed response of free-running model ship to full-scale 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 confirms JSC gives safe side estimates of stopping ability with regard to the track reach and stopping time with acceptable margin. The analysis shown here proves the advantage of JSC comparing with possible other control methods of free-running model ships.