Identification of Hydrodynamic Coefficients from Standard Manoeuvres for a Series of Twin-Screw Ships

Interest in ship manoeuvrability has increasingly grown during last decades, both for merchant and naval ships; resulting in the adoption by IMO of RESOLUTION MSC137(76) and in publication by NATO of ANEP 70. Ship manoeuvrability characteristics estimation is strongly related to the accuracy in determination of the hydrodynamic coefficients which specify mathematical model used in simulation tools. Hydrodynamic coefficients are usually estimated, in preliminary design stages, from regression formulas based on existing data, which may lead to inaccurate predictions for non conventional vessels or ships exceeding experimental data base parametric range. In this work a previously developed method for hydrodynamic coefficients identification from standard experimental manoeuvres is systematically applied to a series of twin-screw ships, with the primary aim of investigating the possibility of improving the prediction capability of existing manoeuvring simulators for this specific ship type, and the general aim of establishing a low-risk procedure for ship manoeuvrability prediction in the preliminary design stages.