Experimental and numerical investigation of asymmetrical behaviour of rudder/propeller for twin screw ships

The present work addresses the asymmetrical functioning of rudder/propeller complex of twin screw/twin rudders ships. A series of free running model test results are analysed, with the aid of some simplified numerical calculations. this analysis allows to show the asymmetrical propeller loading during manoeuvres and the considerably different rudder functioning. A possible simplified model to include these effects in manoeuvring simulators is proposed and discussed, allowing to define the needs for future research activities to further improve the understanding of the different phenomena shown.