Abstract: A controllable pitch marine propeller has blades carried by a hub and a hydraulic actuator housed in the hub and coupled to the blades for altering the pitch angle of the blades in both directions, astern and ahead, and also beyond the ahead position to a feathered position. A servo-control system controls the actuator to adjust the blade pitch angle, the control system having a blade position feedback loop by which the system operates with positional feedback over the range of pitch angle between astern and full ahead pitch angles. However, the demand signal for blade feathering renders the feedback loop inoperative, and the hydraulic actuator then moves the blades into the feathering position without feedback action.