Yoshihisa Okada, Deputy General Manager, Propeller Design Dept., Nakashima Propeller Co Ltd presentation during the 2015 GREEN4SEA Forum NAKASHIMA PROPELLER developed ECO-Cap as a new ESD with FRP. The strength of FRP is higher than that of Nickel Aluminium Bronze, therefore ECO-Cap was able to adopt thin fins on propeller caps for low resistance. As the results, the improvement of F.O.C. by ECO-Cap was confirmed abt. 2.8% in operating condition. On the other hand, NAKASHIMA PROPELLER developed “Ultimate Rudder” of new design concept by FRP. And we optimized the profile of “Ultimate Rudder” by CFD and confirmed the efficiency increase from 4.9 to 5.4% in self-propulsion test.   My presentation refers to our new product, GPX Propeller. This is the design concept of GPX propeller: Non Hub Vortex Small Blade Area Tip Rake I am going to explain Non Hub Vortex and Small Blade Area.   Hub vortex technology Conventional Propeller GPX Propeller The conventional propeller has a strong hub vortex causing energy loss. On the contrary, the GPX propeller can absorb hub vortex cavitation saving energy. Small blade area technology Conventional Propeller GPX Propeller GPX propeller adapts narrow legs, so expanded area decrease max. 20%. In that way it is reduced the...