Course-keeping and turning circle analysis in early ship design stage

The course-keeping is an important ship’s quality. Starting with the initial ship design process, the knowledge of the stability on route represents a main component of the manoeuvring performance. Also, the turning circle characteristics must be estimated in order to analyse the manoeuvring performance. Preliminary theoretical methods may be used to study the course-keeping quality and turning circle characteristics. For that purpose, the numerical solution of the Nomoto equation based on the Runge-Kutta method can be applied in order to compute the turning rate of the ship and to analyse the spiral manoeuvre. A new computer code, in Java language, was developed in the Research Centre of the Naval Architecture Faculty from “Dunarea de Jos” University of Galati in order to analyse the ship’s stability on route. Also, the turning circle characteristics are estimated on the basis of statistical relations. Practical evaluations based on the computer code were presented in this paper. The conclusions reveal the possibility to use the new computer code for the course-keeping and turning circle analyse in the preliminary design stage.