Stick control system for waterjet boats

Abstract

A waterjet-driven boat has a reversing bucket for controlling forward/reverse thrust and a rotatable nozzle for controlling sideward forces. A bucket position sensor is connected to the reversing bucket, and the bucket is controlled using the output of the position sensor to enable the bucket to be automatically moved to a neutral thrust position. Similarly, a nozzle position sensor is connected to the nozzle, and the nozzle is controlled using the output of the nozzle position sensor so that the nozzle may be automatically returned to a zero sideward force position. A joystick with two axes of motion may be used to control both the bucket and the nozzle. The joystick has built-in centering forces that automatically return it to a neutral position, causing both the bucket and nozzle to return to their neutral positions.

What is claimed is:  
     
         1 . A boat of the type driven by a waterjet, the boat comprising 
 a waterjet drive assembly, the assembly including 
 a nozzle directing a flow of water generally along the longitudinal axis of the boat, the nozzle being capable of rotation about a generally vertical axis to provide left and right sideward forces on the boat, and  
 a reversing bucket for reversing the direction of a variable amount of the flow of water emerging from the nozzle, the reversing bucket being adjustable from any of a plurality of forward thrust positions in which enough water remains unaffected by the reversing bucket that a net forward thrust is maintained, to a neutral thrust position in which a substantial fraction of the flow of water is reversed so that the net thrust of the water reversed and the water not reversed is approximately zero, to any of a plurality of reverse thrust positions in which enough water is reversed that a net reverse thrust is maintained;  
   a bucket position sensor connected to the reversing bucket to sense the position of the reversing bucket;    a bucket drive mechanism connected to the reversing bucket to move the reversing bucket between the forward thrust, neutral thrust, and reverse thrust positions    an electrical control circuit for controlling the drive mechanism in response to the bucket position sensor so that the reversing bucket can be automatically moved to the neutral thrust position from a forward thrust position or from a reverse thrust position.    
     
     
         2 . The boat of  claim 1  further comprising a stick control member connected electrically to the electrical control circuit, the stick control member having a neutral position, at least one forward position, and at least one reverse position, and the electrical circuit and position sensor being configured so that when the stick control member is placed in the neutral position the drive mechanism moves the reversing bucket to the neutral thrust position.  
     
     
         3 . The boat of  claim 2  wherein the stick control member has a centering force that returns the stick to the neutral position when released by the operator.  
     
     
         4 . The boat of  claim 2  or  3  further comprising a nozzle drive mechanism connected to the nozzle and electrically controlled by the electrical control circuit, wherein the stick control member is configured to rotate about a generally vertical axis, and wherein the electrical control circuitry and nozzle drive mechanism are configured so that rotation of the stick produces rotation of the nozzle and sideward forces on the boat.  
     
     
         5 . The boat of  claim 4  further comprising a nozzle position sensor providing an electrical signal representative of the angular position of the nozzle.  
     
     
         6 . The boat of  claim 4  wherein the stick control member has a centering torque that returns the stick to a zero rotation position when released by the operator.  
     
     
         7 . The boat of  claim 6  wherein the waterjet drive is positioned and the nozzle drive and electrical control circuitry configured so that rotation of the stick control member produces a rotation of the-boat in the same rotational direction.  
     
     
         8 . The boat of  claim 2  wherein the boat further comprises a bowthruster, wherein the stick control member is configured td move to the left and right of the neutral position, and wherein the bowthruster and electrical control circuitry are configured so that leftward movement of the stick produces a leftward movement of the bow of the boat and rightward movement of the stick produces rightward movement of the bow.  
     
     
         9 . The boat of  claim 2  wherein the boat further comprises a nozzle drive mechanism connected to the nozzle and electrically controlled by the electrical control circuit, the stick control member is configured to rotate about a vertical axis, the electrical control circuitry and nozzle drive mechanism are configured so that rotation of the stick produces rotation of the nozzle and sideward forces on the boat, the boat further comprises a bowthruster, the stick control member is configured to move to the left and right of the neutral position, and the bowthruster and electrical control circuitry are configured so that leftward movement of the stick produces a leftward movement of the bow of the boat and rightward movement of the stick produces rightward movement of the bow.  
     
     
         10 . The boat of  claim 9  wherein the boat is small (i.e., 75 feet or under in length).  
     
     
         11 . The boat of  claim 2  wherein the bucket position sensor, stick control member, and electrical control circuit are configured to provide at least two modes of operation, a first mode in which a follow-up relationship exists between forward/aft movement of the stick control member and up/down movement of the reversing bucket, and a second mode in which a non-follow-up relationship exists between forward/aft movement of the stick control member and up/down movement of the reversing bucket.  
     
     
         12 . The boat of  claim 11  wherein the boat further comprises 
 a nozzle drive mechanism connected to the nozzle and electrically controlled by the electrical control circuit, wherein the stick control member is configured to rotate about a generally vertical axis, and wherein the electrical control circuitry and nozzle drive mechanism are configured so that rotation of the stick produces rotation of the nozzle and sideward forces on the boat, and  
 a nozzle position sensor providing an electrical signal representative of the angular position of the nozzle, and  
 wherein the nozzle position sensor, stick control member, and electrical control circuit are configured to provide a follow-up relationship between the rotation of the stick control member and rotation of the nozzle.  
 
     
     
         13 . The boat of  claim 11  wherein the electrical circuitry is configured to provide both a docking mode and a power steer mode of operation, 
 wherein in the docking mode of operation, the bucket position sensor, nozzle position sensor, and stick control member are configured so that both bucket position control and nozzle position control have a follow-up relationship to the respective movements of the stick control member, and  
 wherein in the power steer mode of operation, the bucket position sensor, nozzle position sensor, and stick control member are configured so that bucket position control is non-follow-up and nozzle position control is follow-up.  
 
     
     
         14 . The boat of  claim 13  wherein in the power steer mode of operation, the electrical circuitry and stick control member are configured so that rotational movement of the stick member produces less rotation of the nozzle than in the docking mode.  
     
     
         15 . The boat of  claim 13  further comprising a trim adjustment control that permits the operator to adjust an offset between nozzle position and stick rotation.  
     
     
         16 . The boat of  claim 2  further comprising hydraulic control components, including a hydraulic cylinder and hydraulic valve, for carrying out movement of the reversing bucket in response to movements of the stick control member.  
     
     
         17 . The boat of  claim 16  wherein the hydraulic control components are configured to provide two speeds of movement of the hydraulic cylinder, a high speed movement for use when the cylinder is more than a predetermined distance away from the position prescribed by the electrical circuitry, and a low speed movement for use when the cylinder is less than the predetermined distance.  
     
     
         18 . A boat of the type driven by a waterjet, the boat comprising 
 a waterjet drive assembly, the assembly including 
 a nozzle directing a flow of water generally along the longitudinal axis of the boat, the nozzle being capable of rotation about a generally vertical axis to provide left and right sideward forces on the boat, and  
 a reversing bucket for reversing the direction of a variable amount of the flow of water emerging from the nozzle, the reversing bucket being adjustable from any of a plurality of forward thrust positions in which enough water remains unaffected by the reversing bucket that a net forward thrust is maintained, to a neutral thrust position in which a substantial fraction of the flow of water is reversed so that the net thrust of the water reversed and the water not reversed is approximately zero, to any of a plurality of reverse thrust positions in which enough water is reversed that a net reverse thrust is maintained;  
   a bucket drive mechanism connected to the reversing bucket to move the reversing bucket between the forward thrust, neutral thrust, and reverse thrust positions;    a nozzle drive mechanism connected to the nozzle for rotating the nozzle to vary the left and right sideward forces on the boat;    a stick control system in which a first axes of movement corresponds to movement of the bucket, and a second axis movement corresponds to movement of the nozzle; and    an electrical control circuit configured to control the bucket drive mechanism in response to movement of the stick along the first axis, and to control the nozzle drive mechanism in response to movement of the stick along the second axis.