A LOOK INTO MOTION EQUATIONS OF THE 'ESSO OSAKA' MANOEUVRING

A detailed analysis of ship manoeuvring equations for the ‘Esso Osaka’ tanker is carried out in case both full scale motion data and experimental scale model force measurements are combined together. Some issues concerning the external excitations acting during real-world manoeuvring are raised, which enables an identification and/or validation of the manoeuvring mathematical models at the lowest possible level. The role of the ship sway added mass in the surge motion equation is emphasised. Its essential reduction is necessary for an adequate rudder forces identification. Further implications concern the need of the relative and absolute adjustment of hull hydrodynamic sway force and yaw moment as measured in towing tanks.