Abstract: A waterjet propulsion pump (14) is mounted in an opening in a fully submerged intermediate transom (12) located forward of the stern transom (11) and at the aft end of a dependent structural pod (15) on the hull bottom with the pump discharge nozzle (30) lying aft of the intermediate transom. A steering nozzle (50) is mounted on the discharge nozzle (30) for pivotal movement about an axis that lies in a vertical plane. At least one reversing deflector (100 or 300 and 400) is mounted for pivotal movement about an axis that is perpendicular to the vertical plane. A rotatable steering shaft (70, 270) operated by a steering actuator located with the hull (140 or 340) is coupled to the steering nozzle (50 or 250). A hollow reversing shaft (90, 290) is received telescopically over a portion of the steering shaft and is translatable axially relative to the steering shaft by a reversing actuator (150, 350) located within the vessel hull.

Abstract: A waterjet steering and reversing apparatus has a steering nozzle mounted aft of the exit nozzle for pivotal movement about a steering pivot axis that lies in a vertical plane and a reversing deflector that is mounted for pivotal movement about a reversing pivot axis for movement between an inactive position clear of a water jet discharged from the steering nozzle and an operative position in which the water jet impinges on a surface that deflects the water jet to a direction having a forward vector. The reversing pivot axis is perpendicular to the vertical plane and spaced apart from the steering pivot axis. A rotatable steering shaft is coupled at its lower end to the steering nozzle, is coaxial with the steering pivot axis, extends upwardly through an opening in the hull, and has an upper end portion located within the hull. A hollow reversing shaft received telescopically over a portion of the steering shaft is translatable axially relative to the steering shaft.

Abstract: An impeller for a marine waterjet propulsion system has blades that are configured to reduce cavitation, vibration, noise and physical damage to the major components of the propulsion system or host vessel of installation. The leading edge of each blade of the impeller is skewed forwardly over at least the outer 70% of its span, the forward skew being maximum at the tip and being not less than 35.degree.. The impeller has a blade area ratio of not less than 1.5. The chord lengths of each blade increase progressively from the point of minimum skew to the tip, resulting in reduced loading in the cavitation critical region. A partial or full tip band may be affixed to the blade tips.

Abstract: A surface vessel has a hull that is configured to provide a mounting location for a waterjet pump propulsion system that is fully submerged under substantially all operating conditions of the vessel. A waterjet propulsion pump is mounted in an opening in the mounting location of the hull. At least the aft portion of the pump exit nozzle extends aft of the mounting location. A rotatable steering nozzle is coupled to the lower end of a rotatable steering shaft. A rotatable reversing deflector is coupled to the lower end of a rotatable reversing shaft that is either concentric with or parallel to the steering shaft. The steering shaft and reversing shaft extend upwardly through a shared opening or a pair of openings in the hull. Steering and reversing actuators associated with the steering and reversing shafts are located within the hull. A pair of steering deflectors in a "clamshell" relationship is an alternative.

Abstract: A blade of a built-up marine propeller is balanced by forming an open cavity of a predetermined size at a predetermined location proximate to the blade tip, conducting a spin-balancing test in which the blade being balanced and a calibration blade are assembled diametrically opposite each other on a dummy hub to form a simulated two-blade propeller, determining from the test the weight that must be added to the blade to balance the simulated propeller, and affixing a balance member of a predetermined weight in the blade cavity. A cover plate is secured in the cavity opening of the blade in sealed relation, and the external surface of the cover plate is ground to make it fair to the profile of the portion of the blade face adjacent the cavity opening.

Abstract: An inboard servo for a controllable pitch propeller of the force rod type comprises a feedback device comprising a feedback ring located externally of the propeller drive shaft, affixed to the force rod for rotation and axial translation therewith and having a planar surface perpendicular to the propeller drive shaft axis, and a distance-measuring device for substantially continuously detecting the position of the ring, and therefore the position of the force rod. The distance-measuring device directs a high frequency pulsed signal onto the ring surface from a fixed position spaced apart therefrom, detects the signal as it is reflected by the ring surface from a fixed position spaced apart therefrom, and processes the directed and reflected signals to produce a signal indicative of the position of the ring surface based on the time difference between the pulses directed onto the ring surface and the pulses reflected from the ring surface.

Abstract: A controllable pitch marine propeller includes a hub body having a forward section provided with holes for bolts and locating and torque pins and a frontal surface that mates with a hub flange and an internal flange that defines an annular cavity and receives a cup-shaped cross-head. A hub flange and propeller shaft assembly comprises separate hub flange and shaft members joined by at least one weldment formed in a tapered weld cavity and protected by a liner shrink-fitted on the perimeter of the hub flange and a removable plate sealed to the hub liner and the shaft liner.

Abstract: A method of rehabilitating a hub body of a controllable pitch propeller of the type having port openings with threads for the bearing rings and seating surfaces for the O-rings of the blade-mounting assemblies comprises the steps of removing the threads, material underlying the threads and material at the O-ring seating surface to expose clean base metal at the port opening, excavating any casting defects in the exposed base metal area of the port opening, filling the excavated areas and all dowel holes with weld metal, grinding the weld metal flush with the adjacent clean base metal surfaces, positioning the hub such that the axis of the port opening is vertical, and applying weld filler material to the port opening by successive passes, starting at the bottom of the port opening and working upwardly, using an automatically and mechanically manipulated welding torch by pulse arc welding so as to lay down a multiplicity of adjacent beads of weld filler material extending circumferentially of the port opening

Abstract: An oil distribution box for a marine controllable pitch propeller of the type having a main hydraulic servo within a hub for controlling the pitch of propeller blades rotatably carried by the hub and including a directional valve actuated by a tubular valve rod extending through the propeller shaft from the oil distribution box comprises an outer stationary housing, a shaft received within the housing and coupled to the propeller shaft and an auxiliary servo chamber cylinder coupled to the shaft. A piston received in the servo chamber is coupled to the valve rod. Oil is supplied to the valve rod through an elongated annular supply chamber defined between the shaft and the valve rod by spaced-apart seals, a port in the valve rod opening to the supply chamber, a port in the shaft opening to the supply chamber and a journal clearance seal between the housing and shaft in register with the port in the shaft.

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: An inboard servo for a controllable pitch propeller of the force rod type comprises a feedback device having at least two feedback rods connected to the piston and extending through the cylinder end wall and an output ring connected to the rods. An emergency lock-up includes at least two threaded locking rods fastened to the cylinder and passing freely through holes in the feedback ring, each of which receives one or more nuts that can be threaded along the rod for engagement with the feedback ring to lock the piston in a desired position.

Abstract: A controllable pitch marine propeller comprises a hub body carrying a plurality of propeller blades for rotation about pivot axes disposed radially of the hub axis, a force rod extending into the hub body from the propeller shaft, and a cross-head affixed to the force rod and coupled to each propeller blade by a pin and slideway such that the propeller pitch is controlled by fore and aft movements of the force rod. The hub body has a tubular mount spigot that receives the aft end of the shaft with the shaft and mount spigot terminating aftward of the pivot axes of the blades. The cross-head is generally cup-shaped, having a base portion affixed to the force rod aftward of the pivot axes of the blades and a tubular portion extending forewardly from the base portion and surrounding aftward portions of the spigot in telescoping relation. The cross-head in supported in plain bearing relation by the hub body for fore and aft movements.

Abstract: An adjustable diameter screw propeller includes a hub having a plurality of spindles, each mounted in the hub for rotation about an axis disposed radially of the hub axis and a mechanism for synchronously turning the spindles in a common direction. A plurality of propeller blades having a fixed pitch contour and a skew in the range of 60.degree. to 90.degree. are attached to respective ones of the spindles, such that as the spindles are turned, the blades rotate between a first disposition in which the diameter of the propeller is maximum and a second disposition in which the diameter of the propeller is reduced. In addition, the pitch of the propeller increases as the propeller diameter decreases to compensate for the loss of power that would otherwise occur as the propeller diameter is decreased.

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.