EXPERIMENTAL INVESTIGATION OF A DUCTED PODDED PROPULSOR FOR AN UNMANNED-SWATH BOAT

The global performances of a ducted-podded propulsive system designed for an autonomous marine surface vehicle with research purpose are presented. Among the available solutions, present configuration is a viable compromise to operate at low speeds with enhanced power and manoeuvring performances. The azimuthal podded propulsor ensures good manoeuvring capabilities, even at low Froude number, whereas the ducted propeller configuration provides additional thrust contribution. The performances of the full-scale propulsive model are measured in calm water at the CNR-INSEAN towing tank. A suitable experimental set-up is assessed to measure the separated load contribution due to the propeller, duct and pod. Specifically, four propulsive configurations, i.e. the isolated propeller, the ducted propeller, the podded propeller and the ducted podded propeller, have been investigated to establish the interference effects among the parts composing the propulsive system and their influence on the overall performances.