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A steering assist system for a watercraft including a force detection assembly adapted to detect a force further applied to an operator steering control of the watercraft after the steering control is turned to a maximum turning position. The steering assist system also includes a controller configu

A steering assist system for a watercraft including a force detection assembly adapted to detect a force further applied to an operator steering control of the watercraft after the steering control is turned to a maximum turning position. The steering assist system also includes a controller configured to increase a steering force produced by the watercraft in response to an output of the force detection assembly. In one arrangement, the steering assist system increases an output of a propulsion system of the watercraft in proportion to an output of the force detection assembly. In another arrangement, the steering assist system moves a steering force producing member, such as a deflector or rudder, for example, in response to an output of the force detection assembly in addition to, or alternative to, increasing an output of the propulsion system.

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What is claimed is: 1. A watercraft comprising a hull, a propulsion unit supported relative to the hull, a steering system configured to influence a direction of travel of the watercraft, the steering system comprising an operator steering control configured to rotate a steering shaft between a fir

What is claimed is: 1. A watercraft comprising a hull, a propulsion unit supported relative to the hull, a steering system configured to influence a direction of travel of the watercraft, the steering system comprising an operator steering control configured to rotate a steering shaft between a first maximum turning position and a second maximum turning position to permit an operator of the watercraft to control a position of the steering system, a force detection assembly configured to sense a force further applied to the operator steering control after the operator steering control is turned to either of the first and second maximum turning positions, and a control system configured to increase an output of the propulsion unit and to vary the increased output of the propulsion unit in proportion to variations in a magnitude of the forces further applied to the operator steering control at least during the period of increased output. 2. The watercraft of claim 1, wherein the operator steering control is a handlebar assembly and the propulsion unit is a water jet propulsion unit, the water jet propulsion unit comprising a steering nozzle adapted to be turned along with turning of the handlebar assembly. 3. The watercraft of claim 2, additionally comprising a pair of deflectors supported by the steering nozzle for pivotal motion about a generally vertical axis and straddling a flow of water issuing from the steering nozzle in a neutral position, wherein the control system is configured to rotate the pair of deflectors relative to the steering nozzle to divert a flow of water issuing from the steering nozzle in relation to the magnitude of the force. 4. The watercraft of claim 1, wherein the steering system comprises a fixed stop and a moveable stop, the movable stop fixed for movement with the steering shaft, the fixed stop and the movable stop contact one another to define the first and second maximum turning positions, and wherein the force detection assembly comprises a first load receiving element and a second load receiving element associated with one of the fixed and movable stops, and at least one sensor, the first load receiving element configured to receive a compressive load when force is further applied to the operator steering control after the operator steering control is turned to the first maximum turning position, the second load receiving element configured to receive a compressive load when force is further applied to the operator steering control after the operator steering control is turned to the second maximum turning position, the at least one sensor configured to produce an output signal corresponding to a load applied to either of the first and second load receiving elements. 5. The watercraft of claim 4, wherein the force detection assembly is a magnetostrictive detection system, the at least one sensor configured to detect a change in a magnetic permeability of either of the first and second load receiving elements. 6. The watercraft of claim 4, wherein the first and second load receiving elements are constructed from a conductive rubber material and the at least one sensor is configured to detect a change in an electrical resistance of either of the first and second load receiving elements. 7. The watercraft of claim 4, wherein the movable stop comprises a first stop surface and a second stop surface and the first and second load receiving elements are supported within an integral housing, wherein the housing defines, at least in part, the fixed stop. 8. The watercraft of claim 7, wherein axes of the first and second load receiving elements are arranged to form a V-shape when viewed along an axis of the steering shaft, the first stop surface and the second stop surface move along an imaginary circle centered about the axis of the steering shaft, and wherein the axes of the first and second load receiving elements are tangential to the imaginary circle. 9. The watercraft of claim 7, wherein the integral housing is constructed of a non-magnetic material. 10. The watercraft of claim 7, wherein the first load receiving element, the second load receiving element and the at least one sensor are sealed within the housing, with the exception of a contact surface of each of the first and second load receiving elements, by an elastically-deformable synthetic resin material. 11. The watercraft of claim 10, additionally comprising an electric circuit board electrically connected to the force detection assembly, wherein the electric circuit board is housed within the integral housing. 12. The watercraft of claim 11, wherein the electric circuit board is sealed within the integral housing by a shock absorbing material. 13. The watercraft of claim 1, wherein the steering system additionally comprises a linkage assembly configured to define the first and second maximum turning positions, the linkage assembly including a first end movable with the steering shaft and a second end fixed with respect to the hull, the force detection assembly including at least one sensor configured to produce an output signal corresponding with a tension of the linkage assembly. 14. The watercraft of claim 13, wherein the force detection assembly is of a magnetostrictive type, wherein a linkage member of the linkage assembly is constructed of a material that changes in magnetic permeability in response to a change in a tensile load applied to the material, and the at least one sensor is configured to produce an output signal corresponding to a magnetic permeability of the linkage member. 15. The watercraft of claim 1, wherein the steering system additionally comprises a linkage assembly configured to define the first and second maximum turning positions, the linkage assembly including a first end movable with the steering shaft and a second end fixed with respect to the hull, the force detection assembly including at least one load receiving element and at least one sensor, the linkage assembly configured to apply a compressive force to the at least one load receiving element, wherein a magnitude of the compressive force is reduced when force is further applied to the operator steering control after the operator steering control has been turned to either of the first and second maximum turning positions, and wherein the at least one sensor is configured to produce an output signal corresponding with a compressive force applied to the at least one load receiving element. 16. The watercraft of claim 1, wherein the force detection assembly comprises a load receiving element and at least one sensor, the load receiving element configured to be rotated with the steering shaft about an axis of the steering shaft and to receive a torsional load when force is further applied to the operator steering control after the operator steering control is turned to either of the first and second maximum turning positions, the at least one sensor configured to produce an output signal corresponding with a torsional load applied to the at least one load receiving element. 17. A watercraft comprising a hull, a water jet propulsion unit supported relative to the hull and including a steering nozzle, a steering system configured to influence a direction of travel of the watercraft, the steering system comprising an operator steering control movable between a first maximum turning position and a second maximum turning position and configured to permit an operator of the watercraft to control a position of the steering nozzle, a force detection assembly configured to sense a force further applied to the operator steering control after the operator steering control is turned to either of the first and second maximum turning positions, a pair of deflectors supported by the steering nozzle for pivotal motion about a generally vertical axis and straddling a flow of water issuing from the steering nozzle in a neutral position, and a control system configured to rotate the pair of deflectors relative to the steering nozzle to divert a flow of water issuing from the steering nozzle when the force further applied to the operator steering control exceeds a predetermined threshold. 18. The watercraft of claim 17, wherein the control system is configured to rotate the pair of deflectors through an angle proportional to a magnitude of the force further applied to the operator steering control. 19. A watercraft comprising a hull, a propulsion unit supported relative to the hull, a steering system configured to influence a direction of travel of the watercraft, the steering system comprising an operator steering control movable between a first maximum turning position and a second maximum turning position and configured to permit an operator of the watercraft to control a position of the steering system, a force detection assembly configured to sense a force further applied to the operator steering control after the operator steering control is turned to either of the first and second maximum turning positions, at least one rudder supported by the propulsion unit for pivotal motion about a generally horizontal axis from a first position not providing a substantial steering force to a second position configured to provide a steering force with a body of water on which the watercraft is operated, and a control system configured to rotate the at least one rudder toward the second position when the force further applied to the operator steering control exceeds a predetermined threshold. 20. The watercraft of claim 19, wherein the control system is configured to rotate the at least one rudder through an angle proportional to a magnitude of the force further applied to the operator steering control. 21. The watercraft of claim 19, wherein the operator steenng control is a handlebar assembly and the propulsion unit is a water jet propulsion unit, the water jet propulsion unit comprising a steering nozzle adapted to be turned along with turning of the handlebar assembly. 22. The watereraft of claim 21, wherein the at least one rudder comprises a pair of rudders straddling a flow of water issuing from the steering nozzle. 23. A steering assist method for a watercraft having an operator steering control configured to be turnable between but not substantially beyond maximum port and starboard turning positions and a propulsion unit, the method comprising determining when the operator steering control has been turned to either one of a port or starboard maximum turning position and when a magnitude of a further steering force that has been applied to the operator steering control is greater than a predetermined magnitude, detecting variations in the magnitude of a force above the predetermined magnitude further applied to the operator steering control after the operator steering control is turned to one of the maximum turning positions, and varying a steering force of the watercraft in proportion with the variations in the magnitude of force further applied to the operator steering control above the predetermined magnitude at least during varying the steering force. 24. The method of claim 23, wherein the steering force is increased in proportion to a magnitude of the force. 25. The method of claim 23, wherein the step of increasing a steering force involves increasing an output of a propulsion unit of the watercraft. 26. The method of claim 23, wherein the step of increasing a steering force involves diverting a flow of water issuing from a steering nozzle of a water jet propulsion unit of the watercraft. 27. The method of claim 23, wherein the step of increasing a steering force involves lowering at least one rudder into a position to contact a body of water in which the watercraft is operating. 28. A watercraft comprising a hull, a propulsion unit supported relative to the hull, a steering system configured to influence a direction of travel of the watercraft, the steering system comprising an operator steenng control configured to rotate a steering shaft between port and starboard maximum steering positions, the steering system being configured such that the operator steering control cannot be rotated substantially beyond the port and starboard maximum steering positions, a control system configured to increase an output of the propulsion unit after the operator steering control has been rotated to either of the port and starboard maximum steering positions and a further force has been applied, the control system including means for varying the output of the propulsion unit in proportion with changes in magnitude of the further force applied to the operator steering control. 29. A watercraft comprising a hull, a propulsion unit supported relative to the hull, a steering system configured to influence a direction of travel of the watercraft, the steering system comprising an operator steering control configured to rotate a steering shaft between a first maximum turning position and a second maximum turning position to permit an operator of the watercraft to control a position of the steering system, a force detector configured to sense a force further applied to the operator steering control after the operator steering control is turned to either of the first and second maximum turning positions, and a control system configured to increase an output of the propulsion unit in response to the force sensed by the force detector.