TYPICAL HULL-RUDDER-PROPELLER INTERFERENCES FOR TWIN-SCREW SHIPS WITH TRANSOM STERN

Twin-screw ships with transom stern have shown large variations in the components of the propulsive coefficient. Some significant parameters in the propeller-hull-rudder interaction problem have been identified and their effects evaluated in both a generalized sense and a specific LHA ship model. The most important conclusions arising from LHA-model experiments and other investigations are: propeller-rudder gap ratio was a major parameter in propulsion efficiency. The variable wake at the propeller was of paramount importance in selecting propeller direction of rotation exerted a dominant effect on the hull efficiency elements of an LHA model, and, for that case, the superiority of inward rotation with regard to propulsive coefficient was explained. (Author)