Abstract: A system that allows a boat propeller to maintain a constant blade speed by varying the pitch of the propeller in order to allow the boat's motor to operate at an optimum RPM. The system includes a governor that sends hydraulic fluid to an annular piston, which in turn controls the pitch of the boat propeller blades so that the torque experienced by the engine is kept approximately constant.

Abstract: An adjustable pitch boat propeller system adapted for mounting on a drive shaft of a marine drive unit of a boat. The propeller includes an hub that has been adapted for mounting over the drive shaft of the boat, the hub having an external surface and internal annular surface. An annular piston is mounted against the internal annular surface and connected to a plurality of blades which are pivotally connected to the external surface of the hub by way of a linkage that allows pivoting the plurality of blades in response to movements of the annular piston.