The stern end of a seawater hull has a rotor hub with propeller blades thereon. The rotor hub is rotated for propulsion of the hull by means of a propeller shaft extending through a sealed compartment within the hull. Such sealed compartment and an electrically powered control system is disposed within the hull to automatically adjust angular deflection of deformable tip portions of the propeller blades by means of blade embedded actuators, in response to varying input signals which respectively reflect changes in seawater conditions such as temperature and strain imposed on the propeller blades during propelling rotation of the rotor hub.