A novel watercraft propulsion device is disclosed that includes multiple propulsive elements improving power and efficiency over prior designs. A self-adjusting variable pitch propeller is combined with a water jet and an exhaust driven turbine to provide optimal thrust and efficiency across the range of engine power, load and watercraft speed. In the preferred embodiment, propulsive elements are axially disposed around a central drive shaft and exhaust port with the combined water jet/exhaust turbine disposed closest to drive shaft and the variable pitch propeller attached to the exterior of the water jet housing. A rotating duct is fixed to the propeller blades and rotates with the blades to reduce cavitation. Combined apparatus provides increased performance and efficiency over all watercraft speeds/load as well as additional safety due to the ducted propeller.

A propeller (1) and a respective use method are described, comprising a cylindrical casing (3), a hub (2) couplable to an engine and rotatably mounted at least partially in the cylindrical casing of the propeller, and at least one blade (4) rotatably pivoted to the cylindrical casing. The hub (2) is rotatable with respect to the cylindrical casing of the propeller, or vice versa, to adjust the fluid dynamic pitch of the at least one blade (4). The propeller further comprises at least one elastic element (8) interposed between the hub (2) and the cylindrical casing (3) and it is characterized in that the elastic element (8) is preloaded to prevent its deformation until the resistant torque opposing the propeller rotation is lower than the torque generated by the preload of the elastic element (8), wherein said at least one blade is arranged on at least one first fixed fluid dynamic pitch before the deformation of the elastic element (8) begins. It is further described a flat spring (100) for propellers, which has a longitudinal development line (MS) and comprises a plurality of notches (103) transversally arranged with respect to the longitudinal development line. At least two distances (MD) between successive notches (103) are different from one another and/or at least two notches (103) are different from one another.

A Pulsed Locomotor (120), for propelling media, fluids and crafts, in fluids and on land, comprising a blade (124) securely connected to a drive shaft (122). Upon reciprocation, the ambient medium is forced towards the trailing edge of the blade (124) thereby causing a reactive locomotion of the apparatus, substantially along the plane of the blade. Apparatus is secured to motor M by fastening through aperture (130). The apparatus can be operated directly by motor M, and indirectly by the reaction momentum imparted to a supporting platform P. Thrust is directed by steering handle (128) about a bearing (126), rotatably coupling to platform P and base C. Lubricant L is supplied to outlets (134) via conduit (136) and inlet (132), to coat the apparatus with a lubricant cavity, for drag reduction. The blade (124) planes along a figure 8 reciprocation path s1e1s2e2s1. Crafts are embodied.

An embodiment of a device for marine surface propulsion of a watercraft is provided that facilitates high speed performance in combination with steering and/or trimming control. The propulsion device may include a support member supportably interconnectable to and pivotable about one or both of a reclined axis and upright axis relative to a watercraft transom. A propeller shaft may be supported by the support member for pivotable movement therewith, and may have a first end interconnectable to a watercraft engine output. A hub body and a plurality of propeller blades may be interconnected to a second end of the propeller shaft for co-rotation therewith, wherein the hub body and propeller blades are pivotable with the support member about the reclined and/or upright axes. A variable pitch actuator may be interconnected to the support member for pivotable co-movement therewith about the reclined and/or upright axis, wherein the variable pitch actuator is provided for adjustably controlling a pitch orientation of the propeller blades.

In response to a torque that is applied to a clutch module not exceeding a torque threshold, the clutch module is locked where a blade is configured to be at a first pitch angle in response to the clutch module being locked. In response to the torque that is applied to the clutch module exceeding the torque threshold, the clutch module is released where the blade has a range of motion which extends from the first pitch angle to a second pitch angle in response to the clutch module being released.

A pitch angle indicator system indicates a pitch angle of blades of a propeller of a marine propulsion unit. A mechanical link couples at least one of the blades to a first end of a first rod. An indicator is coupled to a second end of the first rod. The mechanical link is configured to convert a change in the pitch angle into a rotation of the first rod about its longitudinal axis. The indicator is configured to provide an indication of the amount of rotation of the first rod about the longitudinal axis.

A pitch angle indicator system indicates a pitch angle of blades of a propeller of a marine propulsion unit. A mechanical link couples at least one of the blades to a first end of a first rod. An indicator is coupled to a second end of the first rod. The mechanical link is configured to convert a change in the pitch angle into a rotation of the first rod about its longitudinal axis. The indicator is configured to provide an indication of the amount of rotation of the first rod about the longitudinal axis.

A hydraulic rotary feed-through with a neck which is accommodated in a housing via a bearing arrangement and through a pressurized fluid line extends to a pressure space with a seal arrangement provided axially between the pressure space and the bearing arrangement, the bearing arrangement and the seal arrangement are disposed in frames which are accommodated in the housing axially engaged with one another under pressure.

A yoke plate arrangement may comprise a yoke plate, a wear plate comprising a wear surface and a contact surface, wherein a post extends from the contact surface, and a yoke plate ear extending from the yoke plate in a radial direction, wherein a first aperture is disposed in the yoke plate ear, the post located at least partially within the first aperture, the contact surface being in contact with the yoke plate ear. The yoke plate arrangement may further comprise a retaining feature for coupling the wear plate to the yoke plate. The wear surface may be for engaging a trunnion bearing.

A novel watercraft propulsion device is disclosed that includes multiple propulsive elements improving power and efficiency over prior designs. A self-adjusting variable pitch propeller is combined with a water jet and an exhaust driven turbine to provide optimal thrust and efficiency across the range of engine power, load and watercraft speed. In the preferred embodiment, propulsive elements are axially disposed around a central drive shaft and exhaust port with the combined water jet/exhaust turbine disposed closest to drive shaft and the variable pitch propeller attached to the exterior of the water jet housing. A rotating duct is fixed to the propeller blades and rotates with the blades to reduce cavitation. Combined apparatus provides increased performance and efficiency over all watercraft speeds/load as well as additional safety due to the ducted propeller.