Abstract: The pitch of a marine controllable pitch propeller is detected by a motion/DC current transducer in the propeller hub. Circuitry rotating with the propeller shaft converts an AC power signal to DC for energization of the transducer and converts a DC output signal from the transducer to AC. The AC power and output signals are transferred from the rotating circuit to a stationary circuit in the vessel hull by rotary transformers. There are no contacts between relatively moving parts of the transducer or rotary transformers, thus ensuring long life for the pitch detection system.

Abstract: Possible damage to a clutch caused by engagement or disengagement when the engine is running at a high speed is prevented by an engine-clutch control interlock system which prevents the clutch from being engaged or disengaged except when the engine is running at a speed below a nominal, selected idle speed. The system comprises an engine speed monitor which produces a speed signal indicative of whether the engine is running above or below the selected idle speed, a clutch control monitor which produces a signal indicative of whether or not a clutch actuator control signal is being generated and a clutch status monitor which produces a signal indicative of whether the clutch is engaged or disengaged. A clutch actuator signal is conducted to the clutch either to engage or disengage it only when the monitors indicate that a clutch control signal is being generated and the engine is running below the nominal idle speed.

Abstract: A control system equalizes the torques of a lead and a slave engine driving a common load by comparing the throttle settings of the engines and controlling the slave engine throttle with a speed signal equal to the algebraic sum of the lead engine speed signal and a control adjustment signal equal to the sum of an adjusted, selected gain times the sum of the instantaneous error signal and the integral of the error signal over an adjusted, selected reset time.