Abstract: A marine propeller possessing several features; e.g., one-piece cast or molded construction which in one embodiment preferably of the invention is a plastic of the class including polyester; an improved center or core structure in the form of a nave or barrel having an annular wall concentrically surrounding a power-shaft-receiving hub joined to the annular wall by relatively thin spokes configured as vanes functioning as an interior turbine. Propeller blades are joined to and project radially from the exterior of the nave in typical fashion.