There is provided mechanisms for controlling movement of a propeller shaft on a vessel. A controller includes processing circuitry. The processing circuitry is configured to cause the controller to detect movement of the propeller shaft by determining a signature of a sustained oscillation of the propeller shaft. The processing circuitry is configured to cause the controller to control movement of the propeller shaft according to the determined signature.

There is provided mechanisms for controlling movement of a propeller shaft on a vessel. A controller includes processing circuitry. The processing circuitry is configured to cause the controller to detect movement of the propeller shaft by determining a signature of a sustained oscillation of the propeller shaft. The processing circuitry is configured to cause the controller to control movement of the propeller shaft according to the determined signature.

In a marine vessel, a propulsion system comprises at least one propeller having a direction of rotation about a drive shaft and a bulbus protrusion extending from the hull associated with each of the at least one propeller, each protrusion extending from the hull of the vessel, each protrusion receiving and rotatably supporting the at least one propeller. Each protrusion extends between leading and trailing ends and has a substantially circular cross section along a length between the leading and trailing ends having and a leading portion extending from the leading end wherein the leading portion is angled away from the centerline of the hull.

In a marine vessel, a propulsion system comprises at least one propeller having a direction of rotation about a drive shaft and a bulbus protrusion extending from the hull associated with each of the at least one propeller, each protrusion extending from the hull of the vessel, each protrusion receiving and rotatably supporting the at least one propeller. Each protrusion extends between leading and trailing ends and has a substantially circular cross section along a length between the leading and trailing ends having and a leading portion extending from the leading end wherein the leading portion is angled away from the centerline of the hull.

A propeller device for aircraft, spacecraft or watercraft comprising two or more blades and a spinner. The blades are arranged on a hub so that they can be in a deployed or a retracted position. The spinner comprises first, second and third movable portions configured for allowing deploying or retracting the blades and for keeping the blades deployed or retracted.

A propeller device for aircraft, spacecraft or watercraft comprising two or more blades and a spinner. The blades are arranged on a hub so that they can be in a deployed or a retracted position. The spinner comprises first, second and third movable portions configured for allowing deploying or retracting the blades and for keeping the blades deployed or retracted.

A marine vessel has a hull with a bottom, a bow, a stern, and a propulsion arrangement including at least three propulsion units arranged at the stern of the marine vessel. The marine vessel has a base line and a centerline. The at least three propulsion units include a fixed centerline shaft propulsion unit with a shaft line and a propeller, and two turnable propulsion units with respective propellers and arranged at opposite sides of the fixed centerline shaft propulsion unit for steering of the marine vessel. For improving thrust efficiency, while maintaining optimal steering capability, the propeller of the fixed centerline shaft propulsion unit is arranged at a given distance aft of the stern of the marine vessel.

Disclosed is an control device of an outboard motor, including: a computation unit configured to set, as a starting point, a timing before a gearshift mechanism is shifted from forward to neutral after an accelerator opening level is fully closed in a case where an operator's manipulation is performed from forward to neutral, and compute a time-series change of an engine rotation speed as a simulated ship speed on the basis of the engine rotation speed detected by an engine rotation speed detector at the starting point; and a control unit configured to control an actuator such that, in a case where the operator's manipulation is performed from forward to reverse through neutral, the gearshift mechanism is maintained in the neutral position until the simulated ship speed estimated by the computation unit becomes a predetermined threshold value or lower, and is then shifted to reverse.

Disclosed is an control device of an outboard motor, including: a computation unit configured to set, as a starting point, a timing before a gearshift mechanism is shifted from forward to neutral after an accelerator opening level is fully closed in a case where an operator's manipulation is performed from forward to neutral, and compute a time-series change of an engine rotation speed as a simulated ship speed on the basis of the engine rotation speed detected by an engine rotation speed detector at the starting point; and a control unit configured to control an actuator such that, in a case where the operator's manipulation is performed from forward to reverse through neutral, the gearshift mechanism is maintained in the neutral position until the simulated ship speed estimated by the computation unit becomes a predetermined threshold value or lower, and is then shifted to reverse.

A front propeller on a main shaft communicated from one end to an engine transmission; the propeller having a hub and a plurality of blades extending radially outwardly from the hub; a rear propeller co-axially to, and spaced apart from, the front propeller rearwardly in an axial direction having a hub and a plurality of blades extending radially outwardly from the hub. An adaptor is coaxial with the main shaft and comprising a second shaft for supporting the rear propeller. A plurality of pitched-formed seating surfaces having ramps, are spaced apart from the second shaft in axial direction. An adaptor communicates with the rear side of the front propeller in the axial direction; a plurality of locking elements are movable in the axial direction, each being in contact with the seating surfaces of the adaptor, and communicate with the rear propeller from the other end.