Identification of Hydrodynamic Coefficient from Standard Manoeuvres

The purpose of the present paper is to outline a procedure for the identification of the hydrodynamic coefficients from experimental data, either full-scale or model-scale, on standard zigzag and turning circle manoeuvres. To this end a ship was selected for which experimental results from PMM model-scale tests and standard manoeuvres from full-scale tests were available and two sets of standard manoeuvres were considered, zigzag and turning circle. The most influent hydrodynamic coefficients (resulting from an initial sensitivity analysis) were the unknown parameters for the identification procedure. This procedure was based on the iterative use of our manoeuvring simulation program (SIMSUP) within the framework of a numerical optimization package (FRONTIER), having as objective to be minimized an error function made up of the main parameters of the two manoeuvres. The proposed identification procedure allows to refine the predictions based on the preliminary estimation of the coefficients through the regression formulas incorporated in SIMSUP, even if it was not yet possible to identify univocally a pre-determined set of hydrodynamic coefficients. Among the benefits of the proposed procedure is the feasibility to exploit any available experimental data-base of standard manoeuvres in order to extract a set of hydrodynamic coefficients, ready to be used for computer simulations or to build up regression formulas.