Deriving mathematical manoeuvring models for bare ship hulls using viscous flow calculations

Abstract

To assess the manoeuvrability of ships at the early design stage, reliable simulation models are required. Traditionally, these tools have used empiric descriptions of the forces and moments on the ship’s hull. However, nowadays new computational techniques are available enabling more reliable predictions of the manoeuvring behaviour of ships. In this article, a mathematical manoeuvring model to predict the forces and moments on a bare ship hull is presented. Special attention is paid to application in simulators in which also astern or sideways manoeuvring should be possible. The hydrodynamic derivatives in this model were determined by a hybrid approach using results of viscous flow calculations supplemented by semi-empirical methods. It was demonstrated that this approach leads to a considerable improvement in the prediction of the forces and moments on the ship compared to using conventional empiric derivatives published in the literature.