An Interactive Tool For Propeller Selection According to Electric Motor Exploration: An Electric Boat Design Case Study

Inland waterway transportation is widely used in intermediate and minor cities in South America, the energy demand of this kind of transportation is much higher compared with street vehicles. Therefore, improving the efficiency of powertrains of boats is crucial to make electric-powered boats technology feasible. When a combustion boat is designed there are not as many energy limitations as in an electric-powered boat. Therefore, power requirements predictions consider high inefficiencies in some system stages, resulting in power overdimensioning. Thus, there are opportunities to achieve more efficient designs, considering the reduction of energy requirements without resulting in considerable losses in boat performance. To tackle this issue, this paper proposes a methodology for propeller selection according to the definition of a suitable electric motor for a given context, maximizing propeller efficiency and, consequently, reducing power demand. The proposed methodology was implemented in an interactive tool, designed to help in the selection of the correct electric-motor/propeller match in early design stages, under stationary conditions. An algorithm was developed to determine the efficiency of a propeller in a given operating point, for the particular case of open-water characteristics of B-series propellers and the power curve of a Brushless Direct Current (BLDC) motor. Finally, a passenger electric-boat, designed to transport people and goods, in smallsize villages in South-America, is presented as a case of study.