Patent Publication Number: US-2021171175-A1

Title: Method and apparatus for controlling waterjet-driven marine vessel

Description:
This application claims the benefit under 35 U.S.C. § 120 and is a divisional of U.S. patent application Ser. No. 14/469,465 filed Aug. 26, 2014, which claims the benefit under 35 U.S.C. § 120 and is a continuation of U.S. patent application Ser. No. 13/740,655 filed Jan. 14, 2013, which claims the benefit under 35 U.S.C. § 120 and is a continuation of U.S. patent application Ser. No. 13/406,129 filed Feb. 27, 2012, which claims the benefit under 35 U.S.C. § 120 and is a continuation of U.S. patent application Ser. No. 11/960,676 filed Dec. 19, 2007, which claims priority under 35 U.S.C. § 119(e), to U.S. provisional patent applications Ser. No. 60/870,738, which was filed on Dec. 19, 2006, 60/886,220 which was filed on Jan. 23, 2007 and 60/893,070, which was filed on Mar. 5, 2007, each of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to marine vessel propulsion and control systems. More particularly, aspects of the invention relate to a system and method for controlling the movement of a marine vessel having waterjet propulsion apparatus. 
     BACKGROUND 
     Some marine vessel propulsion systems utilize waterjet propulsion. Such devices include a pump, a water inlet or suction port and an exit or discharge port, which generate a waterjet stream that propels the marine vessel. The waterjet stream may be deflected using a “deflector” to provide marine vessel control by redirecting some waterjet stream thrust in a suitable direction and in a suitable amount. 
     It is sometimes more convenient and efficient to construct a marine vessel propulsion system such that the flow of water through the pump is always in the astern direction, and to have the pump remain engaged in the forward direction (water flow directed astern) while providing other mechanisms for redirecting the water flow to provide the desired maneuvers. 
     One example of a device that redirects or deflects a waterjet stream is a conventional “reversing bucket,” found on many waterjet propulsion marine vessels. A reversing bucket deflects water, and is hence also referred to herein as a “reversing deflector.” The reversing deflector generally comprises a deflector that is contoured to at least partially reverse a component of the flow direction of the waterjet stream from its original direction to an opposite direction. The reversing deflector is selectively placed in the waterjet stream and acts to generate a backing thrust, or force in the backing direction. A reversing deflector may be partially deployed, placing it only partially in the waterjet stream, to generate a variable amount of backing thrust. By so controlling the reversing deflector and the waterjet stream, an operator of a marine vessel may control the forward and backwards direction and speed of the vessel. 
     Safe and useful operation of such waterjet propelled marine vessels also requires the ability to steer the vessel from side to side. Systems for steering marine vessels, commonly used in waterjet-propelled vessels, rotate the exit or discharge nozzle of the waterjet stream from one side to another. Such a nozzle is sometimes referred to as a “steering nozzle.” Hydraulic actuators may be used to rotate an articulated steering nozzle so that the aft end of the marine vessel experiences a sideways thrust in addition to any forward or backing force of the waterjet stream. The reaction of the marine vessel to the side-to-side movement of the steering nozzle will depend on the dynamics of the marine vessel design. 
     Despite the proliferation of the above-mentioned systems, some maneuvers remain difficult to perform in a marine vessel. These include turning the vessel in tight quarters, slowing down or stopping the vessel without forcing the bow down and generally controlling the vessel at slow speeds in a precise manner. 
     BRIEF SUMMARY 
     According to aspects of the invention, there is provided a system that improves upon turns provided by conventional waterjet propulsion systems. According to additional aspects of the invention, there is provided a system that improves upon slowing down or stopping marine vessels as is done by conventional waterjet propulsion systems. According to other aspects of the invention, there is provided a system that improves upon the controllability of the waterjet propulsed marine vessel at low vessel speeds, and according to some aspects improves upon up and down trimming and controlling the trim angle of a craft as is done by conventional waterjet propulsion systems at slow speeds. 
     According to one embodiment, a system for controlling a marine vessel having first and second steering nozzles and corresponding first and second reversing buckets, comprises a speed control device for providing a first vessel control signal that corresponds to a thrust to be provided to the marine vessel, a processor configured to receive the first vessel control signal and that is configured to provide at least one first actuator control signal coupled to the first and second steering nozzles, and at least one second actuator control signal coupled to the first and second reversing buckets. According to this embodiment, the processor is configured to provide the at least one first actuator control signal so that the first and second steering nozzles are turned outward, in response to receipt of the first vessel control signal that corresponds to a command corresponding to a slowing down or stopping of the marine vessel, and the processor is also configured to provide the at least one second actuator control signal so that the first and second reversing buckets are positioned in the waterjet stream of the first and second steering nozzles. 
     According to another embodiment, a system for controlling a marine vessel having first and second waterjets including corresponding first and second steering nozzles and corresponding first and second reversing buckets, comprises a speed control device for providing a first vessel control signal that corresponds to a speed to be provided to the marine vessel, and a processor configured to receive the first vessel control signal, that is configured to provide at least one first actuator control signal to be coupled to and control the first and second waterjets, and that is configured to provide the at least one second actuator control signal to be coupled to and control the first and second steering nozzles and the first and second reversing buckets. The processor is configured to provide the at least one first actuator control signal so as to increase RPMs of the first and second waterjets so as to maintain the speed of the marine vessel, and to provide the at least one second actuator control signal so that the first and second reversing buckets are positioned at least partly in the waterjet stream of the first and second steering nozzles. 
     According to another embodiment, a system for controlling a marine vessel having first and second waterjets including corresponding first and second steering nozzles and corresponding first and second reversing buckets, comprises a speed control device for providing a first vessel control signal that corresponds to a speed to be provided to the marine vessel, and a processor configured to receive the first vessel control signal, that is configured to provide at least one first actuator control signal to be coupled to and control the first and second waterjets, and that is configured to provide the at least one second actuator control signal to be coupled to and control the first and second steering nozzles and the first and second reversing buckets. The processor is configured to provide the at least one first actuator control signal so as to increase RPMs of the first and second waterjets so as to maintain the speed of the marine vessel, and to provide the at least one second actuator control signal so as to point inward the first and second steering nozzles to increase an amount of upward force at a stern of the marine vessel. 
     According to another embodiment, a method for controlling a marine vessel having a speed control device, a first waterjet including a corresponding first steering nozzle and a corresponding first reversing deflector, and a second waterjet including a corresponding second steering nozzle and a corresponding second reversing deflector comprises receiving a first vessel control signal corresponding to a speed to be provided to the marine vessel, generating at least one first actuator control signal and at least one second actuator control signal in response to the first vessel control signal, coupling the at least one first actuator control signal to and controlling the first waterjet and the second waterjet, and coupling the at least one second actuator control signal to and controlling the first and second steering nozzles and the first and second reversing buckets. In addition, the method comprises positioning the first and second steering nozzles outward in response to receipt of the first vessel control signal that corresponds to a command to a slow down or stop the marine vessel, and positioning the first and second reversing buckets in the waterjet stream of the first and second waterjets. 
     According to another embodiment, a method for controlling a marine vessel having a speed control device, a first waterjet including a corresponding first steering nozzle and a corresponding first reversing deflector, and a second waterjet including a corresponding second steering nozzle and a corresponding second reversing deflector, comprises receiving a first vessel control signal corresponding to a speed to be provided to the marine vessel, generating at least one first actuator control signal and at least one second actuator control signal in response to the first vessel control signal, coupling the at least one first actuator control signal to and controlling the first waterjet and the second waterjet, and coupling the at least one second actuator control signal to and controlling the first and second steering nozzles and the first and second reversing buckets. The method further comprises increasing RPMs of the first and second water jets so as to maintain the speed of the marine vessel while positioning the first and second reversing buckets at least partially in the waterjet stream of the first and second waterjets, in response to receipt of the first vessel control. 
     According to another embodiment, a method for controlling a marine vessel having a speed control device, a first waterjet including a correspond first steering nozzle and a corresponding first reversing deflector, and a second waterjet including a corresponding second steering nozzle and a corresponding second reversing deflector, comprises receiving a first vessel control signal corresponding to a speed to be provided to the marine vessel, generating at least one first actuator control signal and at least one second actuator control signal in response to the first vessel control signal, coupling the at least one first actuator control signal to and controlling the first waterjet and the second waterjet, and coupling the at least one second actuator control signal to and controlling the first and second steering nozzles and the first and second reversing buckets. The method further comprises increasing RPMs of the first and second waterjets so as to maintain the speed of the marine vessel while pointing inward the first and second steering nozzles to increase an amount of upward force at a stern of the marine vessel, in response to receipt of the first vessel control signal. 
     According to another embodiment, a system for controlling a marine vessel having first and second waterjets that provide first and second waterjet streams and have corresponding first and second steering nozzles and corresponding first and second reversing buckets, comprises a vessel control apparatus having a degree of freedom that provides a first vessel control signal corresponding to a command for turning the marine vessel in a direction toward one side of the marine vessel, and a processor configured to receive the first vessel control signal and that is configured to provide at least one first actuator control signal and at least one second actuator control signal. The at least one first actuator control signal is to be coupled to and control the first and second steering nozzles, and the at least one second actuator control signal is to be coupled to and control the first and second reversing buckets. In addition, the processor is configured to provide the at least one first actuator control signal so that the first and second steering nozzles are rotated in response to receipt of the first vessel control signal, and the processor is also configured to provide the at least one second actuator control signal so that a differential deflection of the first and second waterjet streams is provided by the first and second reversing buckets in response to receipt of the first vessel control signal. 
     According to another embodiment, a method for controlling a marine vessel having a vessel control apparatus having a degree of freedom, a first waterjet that provides a first waterjet stream and has a corresponding first steering nozzle and a corresponding first reversing deflector, and a second waterjet that provides a second waterjet stream and has a corresponding second steering nozzle and a corresponding second reversing deflector, comprises receiving a first vessel control signal corresponding to a command for turning the marine vessel in a direction toward one side of the marine vessel, generating at least one first actuator control signal and at least one second actuator control signal in response to the first vessel control signal, coupling the at least one first actuator control signal to and controlling the first steering nozzle and the second steering nozzle, and coupling the at least one second actuator control signal to and controlling the first and second reversing buckets. The method further comprises rotating the first and second steering nozzles in response to receipt of the first vessel control signal, and differentially deflecting the first and second waterjet streams of the first and second steering nozzles with the first and second reversing buckets, in response to receipt of the first vessel control signal. 
     According to another embodiment, a marine vessel control system for a marine vessel having a first waterjet including a corresponding first steering nozzle and a corresponding first reversing bucket and a second waterjet including a corresponding second steering nozzle and a corresponding second reversing bucket, comprises a control stick having at least one degree of freedom that provides a first vessel control signal corresponding to movement of the vessel control apparatus along the at least one degree of freedom, a processor configured to receive the first vessel control signal and that is configured to provide at least one first actuator control signal and at least one second actuator control signal, and wherein the at least one first actuator control signal is to be coupled to and control the first and second waterjets, and wherein the at least one second actuator control signal is to be coupled to and control the first and second reversing buckets. The control system further comprises a lockout device that prevents output of the at least one second actuator control signal. 
     According to another embodiment, a system for controlling a marine vessel having first and second steering nozzles and corresponding first and second reversing buckets, comprises a speed control device for providing a first vessel control signal that corresponds to a speed to be provided to the marine vessel, a processor configured to receive the first vessel control signal and that is configured to provide at least one first actuator control signal and at least one second actuator control signal, wherein the at least one first actuator control signal is to be coupled to and control the first and second steering nozzles, and wherein the at least one second actuator control signal is to be coupled to and control the first and second reversing buckets. The processor is configured to provide the at least one first actuator control signal to provide a sub-planning speed to the marine vessel, in response to receipt of the first vessel control signal that corresponds to a command to provide the sub-planning speed to the marine vessel. The processor is also configured to provide the at least one second actuator control signal so that the first and second reversing buckets are positioned at least partly in the waterjet stream of the first and second steering nozzles. 
     According to another embodiment, a method for controlling a marine vessel having a speed control device, a first steering nozzle and a corresponding first reversing deflector, and a second steering nozzle and a corresponding second reversing deflector, comprises receiving a first vessel control signal corresponding to a sub planning speed to be provided to the marine vessel, generating at least one first actuator control signal and at least one second actuator control signal in response to the first vessel control signal, coupling the at least one first actuator control signal to and controlling the first steering nozzle and the second steering nozzle, and coupling the at least one second actuator control signal to and controlling the first and second reversing buckets. The method further comprises maintaining the sub planning speed of the marine vessel while positioning the first and second reversing buckets at least partially in the waterjet stream of the first and second steering nozzles, in response to receipt of the first vessel control signal that corresponds to a command to provide the sub-planning speed to the marine vessel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an outline of a marine vessel and various axes and directions of motion referenced thereto; 
         FIG. 2  illustrates an exemplary embodiment of a control stick and associated degrees of freedom; 
         FIG. 3  illustrates an exemplary vessel with a dual waterjet propulsion system and controls therefore; 
         FIG. 4  illustrates another exemplary vessel with a dual waterjet propulsion system and controls therefore; 
         FIG. 5  illustrates an exemplary control apparatus and associated actuator; 
         FIG. 6  illustrates an exemplary control system (cabling) diagram for a single waterjet propulsion system; 
         FIG. 7  illustrates an exemplary control system (cabling) diagram for a dual waterjet propulsion system; 
         FIG. 8  illustrates an exemplary control processor unit and exemplary set of signals; 
         FIGS. 9A-9C  illustrate an exemplary set of control functions and signals for a single waterjet vessel corresponding to motion of a control stick in the x-direction; 
         FIGS. 10A-10B  illustrate an exemplary set of control functions and signals for a single waterjet vessel corresponding to motion of a control stick in the y-direction; 
         FIGS. 11A-11B  illustrate an exemplary set of control functions and signals for a single waterjet vessel corresponding to motion of a throttle and helm control apparatus; 
         FIGS. 12A-12D  illustrate exemplary maneuvers provided by motion of a control stick and helm for a single waterjet vessel; 
         FIG. 13A  illustrates a signal diagram an exemplary marine vessel control system for a dual waterjet vessel; 
         FIG. 13B  illustrates a signal diagram of another embodiment of a marine vessel control system for a dual waterjet vessel; 
         FIGS. 13C-13D  illustrate thrust modulation of a vessel using the reversing, in part, to accommodate the thrust modulation according to some embodiments; 
         FIGS. 13E-13F  illustrate thrust modulation of a vessel using engine RPMs only and without using, in part, the reversing bucket; 
         FIG. 13G  illustrates resulting vessel movement when modulating the thrust according to the technique illustrated in  FIGS. 13C-13D ; 
         FIG. 13H  illustrates resulting vessel movement when modulating the thrust according to the technique illustrated in  FIGS. 13E-13F ; 
         FIG. 13I-A - 13 I-D illustrates a signal diagram of another exemplary marine vessel control; 
         FIGS. 14A-C  illustrate an exemplary set of (port) control functions and signals of the vessel control system corresponding to motion of a control stick in the x-direction, for a dual waterjet vessel; 
         FIGS. 14D-F  illustrate another exemplary set of (port) control functions and signals of the vessel control system corresponding to motion of a control stick in the x-direction, for a dual waterjet vessel; 
         FIGS. 15A-C  illustrate an exemplary set of (starboard) control functions and signals of the vessel control system corresponding to motion of a control stick in the x-direction, for a dual waterjet vessel; 
         FIGS. 15D-F  illustrates another exemplary set of (starboard) control functions and signals of the vessel control system corresponding to motion of a control stick in the x-direction, for a dual waterjet vessel; 
         FIGS. 16A-16B  illustrate an exemplary set of (port) control functions and signals for a dual waterjet vessel corresponding to motion of a control stick in the y-direction; 
         FIGS. 17A-17B  illustrate an exemplary set of (starboard) control functions and signals for a dual waterjet vessel corresponding to motion of a control stick in the y-direction; 
         FIGS. 18A-18B  illustrate an exemplary set of control functions and signals for a dual waterjet vessel corresponding to motion of a helm control apparatus; 
         FIGS. 19A-19B  illustrate an exemplary set of control functions and signals for a dual waterjet vessel corresponding to motion of a throttle control apparatus; 
         FIGS. 20A-20D  illustrate exemplary maneuvers provided by motion of a control stick and helm for a dual waterjet vessel; 
         FIGS. 21A-21C  illustrate an exemplary subset of motions of an integral reversing bucket and steering nozzle; 
         FIGS. 22A-22B  illustrate thrust and water flow directions from the integral reversing bucket and steering nozzle of  FIGS. 21A-21C ; 
         FIG. 23  illustrates plots of thrust angle versus nozzle angle for the integral reversing bucket and steering nozzle assembly of  FIGS. 21A-21C ; 
         FIGS. 24A-24C  illustrate an exemplary subset of motions of a laterally-fixed reversing bucket and steering nozzle; 
         FIGS. 25A-25B  illustrate thrust and water flow directions from the laterally-fixed reversing bucket and steering nozzle of  FIGS. 24A-24C ; 
         FIG. 26  illustrates plots of thrust angle versus nozzle angle for the laterally-fixed reversing bucket and steering nozzle assembly of  FIGS. 24A-24C ; 
         FIG. 27  illustrates an alternate embodiment of a vessel control apparatus to be used with embodiments of marine vessel control system of this disclosure, and resulting vessel maneuvers; 
         FIG. 28  illustrates a control system (cabling) diagram for an alternative embodiment of a dual waterjet propulsion system, with a remote control interface; 
         FIG. 29  illustrates an exemplary signal diagram for the embodiment of the marine vessel control system for a dual waterjet vessel, with a remote control interface of  FIG. 28 ; 
         FIG. 30  illustrates a signal diagram of one exemplary embodiment of a marine vessel control system for a vessel comprising dual waterjets and bow thruster; 
         FIGS. 31A-D  illustrates maneuvers resulting from motion of a control stick and helm for the embodiment of the marine vessel control system of  FIG. 30 ; 
         FIGS. 32A-B  illustrate a signal diagram of another embodiment of a marine vessel control system for a vessel comprising dual waterjets and bow thruster; 
         FIG. 33A  illustrates marine vessel motion and the net force induced with dual waterjets and with the corresponding reversing buckets in a neutral thrust position; 
         FIG. 33B  illustrates marine vessel motion and the net force induced with dual waterjets and with the corresponding reversing buckets in a differential thrust position; 
         FIG. 34A  illustrates marine vessel motion and the resultant thrust angle with dual waterjets in the maximum nozzle rotation position and with the corresponding reversing buckets in the full up position; 
         FIG. 34B  illustrates marine vessel motion and the resultant thrust angle with dual waterjets in the maximum nozzle rotation position and with the corresponding reversing bucket to the side of vessel rotation in the waterjet stream and with the other reversing bucket in the full up position; 
         FIGS. 35A-B  illustrate vessel motion for the turn movements commanded according to  FIGS. 34A and 34B ; 
         FIG. 36A  illustrates a variable output pushbutton that can be used to initiate a bucket assisted turn according to the invention; 
         FIG. 36B  illustrates a joystick configured with the thumb controlled variable output pushbutton of  FIG. 36A  that can be used to initiate a bucket assisted turn by pushing in the pushbutton while making a turn; 
         FIGS. 37A-37E  illustrates an embodiment of a dual waterjet control process that includes process for initiating a bucket assisted turn with the joystick of  FIGS. 36A-36B ; 
         FIG. 38  illustrates a detailed view of the port and starboard Bucket Turn Modules the dual waterjet control process illustrated in  FIGS. 37A-37E ; 
         FIG. 39  illustrates typical net forces and corresponding waterjet vectors resulting from using reversing buckets to slow a marine vessel according to the related art; 
         FIG. 40  illustrates improved net forces to the marine vessel and corresponding waterjet vectors resulting from using reversing buckets to slow the marine vessel according to aspects of the invention; 
         FIG. 41  illustrates exemplary marine vessel parameters and net force vectors on the marine vessel when operating the marine vessel at low speeds of the waterjet; 
         FIG. 42  illustrates improved net forces to the marine vessel and corresponding waterjet vectors resulting from at partially using reversing buckets and the waterjets to increase marine vessel marine vessel maneuverability at low vessel speeds, according to aspects of the invention; and 
         FIG. 43  illustrates improved net forces to the marine vessel and corresponding waterjet vectors resulting from pointing in the waterjets and using an inner portion of the reversing buckets according to aspects of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In view of the above discussion, and in view of other considerations relating to design and operation of marine vessels, it is desirable to have a marine vessel control system which can provide forces in a plurality of directions, such as a trimming force, and which can control thrust forces in a safe and efficient manner. Some aspects of the present invention generate or transfer force from a waterjet stream, initially flowing in a first direction, into one or more alternate directions. Other aspects provide controls for such systems. 
     Aspects of marine vessel propulsion, including trim control, are described further in pending U.S. patent application, Ser. No. 10/213,829, which is hereby incorporated by reference in its entirety. In addition, some or all aspects of the present invention apply to systems using equivalent or similar components and arrangements, such as outboard motors instead of jet propulsion systems and systems using various prime movers not specifically disclosed herein. 
     Prior to a detailed discussion of various embodiments of the present invention, it is useful to define certain terms that describe the geometry of a marine vessel and associated propulsion and control systems.  FIG. 1  illustrates an exemplary outline of a marine vessel  10  having a forward end called a bow  11  and an aft end called a stern  12 . A line connecting the bow  11  and the stern  12  defines an axis hereinafter referred to the marine vessel&#39;s major axis  13 . A vector along the major axis  13  pointing along a direction from stern  12  to bow  11  is said to be pointing in the ahead or forward direction  20 . A vector along the major axis  13  pointing in the opposite direction (180° away) from the ahead direction  20  is said to be pointing in the astern or reverse or backing direction  21 . 
     The axis perpendicular to the marine vessel&#39;s major axis  13  and nominally perpendicular to the surface of the water on which the marine vessel rests, is referred to herein as the vertical axis  22 . The vector along the vertical axis  22  pointing away from the water and towards the sky defines an up direction  23 , while the oppositely-directed vector along the vertical axis  22  pointing from the sky towards the water defines the down direction  24 . It is to be appreciated that the axes and directions, e.g. the vertical axis  22  and the up and down directions  23  and  24 , described herein are referenced to the marine vessel  10 . In operation, the vessel  10  experiences motion relative to the water in which it travels. However, the present axes and directions are not intended to be referenced to Earth or the water surface. 
     The axis perpendicular to both the marine vessel&#39;s major axis  13  and a vertical axis  22  is referred to as an athwartships axis  25 . The direction pointing to the left of the marine vessel with respect to the ahead direction is referred to as the port direction  26 , while the opposite direction, pointing to the right of the vessel with respect to the forward direction  20  is referred to as the starboard direction  27 . The athwartships axis  25  is also sometimes referred to as defining a “side-to-side” force, motion, or displacement. Note that the athwartships axis  25  and the vertical axis  22  are not unique, and that many axes parallel to said athwartships axis  22  and vertical axis  25  can be defined. 
     With this the three most commonly-referenced axes of a marine vessel have been defined. The marine vessel  10  may be moved forward or backwards along the major axes  13  in directions  20  and  21 , respectively. This motion is usually a primary translational motion achieved by use of the vessels propulsion systems when traversing the water as described earlier. Other motions are possible, either by use of vessel control systems or due to external forces such as wind and water currents. Rotational motion of the marine vessel  10  about the athwartships axis  25  which alternately raises and lowers the bow  11  and stern  12  is referred to as pitch  40  of the vessel. Rotation of the marine vessel  10  about its major axis  13 , alternately raising and lowering the port and starboard sides of the vessel is referred to as roll  41 . Finally, rotation of the marine vessel  10  about the vertical axis  22  is referred to as yaw  42 . An overall vertical displacement of the entire vessel  10  that moves the vessel up and down (e.g. due to waves) is called heave. 
     In waterjet propelled marine vessels a waterjet is typically discharged from the aft end of the vessel in the astern direction  21 . The marine vessel  10  normally has a substantially planar bulkhead or portion of the hull at its aft end referred to as the vessel&#39;s transom  30 . In some small craft an outboard propeller engine is mounted to the transom  30 . 
       FIG. 2  illustrates an exemplary vessel control apparatus  100 . The vessel control apparatus  100  can take the form of an electro-mechanical control apparatus such as a control stick, sometimes called a joystick. The control stick generally comprises a stalk  112 , ending in a handle  114 . This arrangement can also be thought of as a control lever. The control stick also has or sits on a support structure  118 , and moves about one or more articulated joints  116  that permit one or more degrees of freedom of movement of the control stick. Illustrated are some exemplary degrees of freedom or directions of motion of the vessel control apparatus  100 . The “y” direction  113  describes forward-and-aft motion of the vessel control apparatus. The “x” direction  111  describes side-to-side motion of the vessel control apparatus  100 . It is also possible in some embodiments to push or pull the handle  114  vertically with respect to the vessel to obtain a vessel control apparatus  100  motion in the “z” direction  115 . It is also possible, according to some embodiments, to twist the control stick along a rotary degree of freedom  117  by twisting the handle  114  clockwise or counter-clockwise about the z-axis. 
     Referring to  FIG. 3 , a waterjet propulsion system and control system for a dual waterjet driven marine vessel are illustrated. The figure illustrates a twin jet propulsion system, having a port propulsor or pump  150 P and a starboard propulsor  150 S that generate respective waterjet streams  151 P and  151 S. Both the port and starboard devices operate similarly, and will be considered analogous in the following discussions. Propulsor or pump  150  drives waterjet stream  151  from an intake port (not shown, near  156 ) to nozzle  158 . Nozzle  158  may be designed to be fixed or articulated, in which case its motion is typically used to steer the vessel by directing the exit waterjet stream to have a sideways component. The figure also illustrates reversing deflector or bucket  154  that is moved by a control actuator  152 . The control actuator  152  comprises a hydraulic piston cylinder arrangement for pulling and pushing the reversing deflector  154  into and out of the waterj et stream  151 P. The starboard apparatus operates similar to that described with regard to the port apparatus, above. 
     The overall control system comprises electrical as well as hydraulic circuits that includes a hydraulic power unit  141 . The hydraulic power unit  141  may comprise various components required to sense and deliver hydraulic pressure to various actuators. For example, the hydraulic unit  141  may comprise hydraulic fluid reservoir tanks, filters, valves and coolers. Hydraulic pumps  144 P and  144 S provide hydraulic fluid pressure and can be fixed or variable-displacement pumps. Actuator control valve  140  delivers hydraulic fluid to and from the actuators, e.g.  152 , to move the actuators. Actuator control valve  140  may be a proportional solenoid valve that moves in proportion to a current or voltage provided to its solenoid to provide variable valve positioning. Return paths are provided for the hydraulic fluid returning from the actuators  152 . Hydraulic lines, e.g.  146 , provide the supply and return paths for movement of hydraulic fluid in the system. Of course, many configurations and substitutions may be carried out in designing and implementing specific vessel control systems, depending on the application, and that described in regard to the present embodiments is only illustrative. 
     The operation of the electro-hydraulic vessel control system of  FIG. 3  is as follows. A vessel operator moves one or more vessel control apparatus. For example, the operator moves the helm  120 , the engine throttle controller  110  or the control stick  100 . Movement of said vessel control apparatus is in one or more directions, facilitated by one or more corresponding degrees of freedom. The helm  120 , for example, may have a degree of freedom to rotate the wheel in the clockwise direction and in the counter-clockwise direction. The throttle controller  110  may have a degree of freedom to move forward-and-aft, in a linear, sliding motion. The control stick  100  may have two or more degrees of freedom and deflects from a neutral center position as described earlier with respect to  FIG. 2 . 
     The movement of one or more of the vessel control apparatus generates an electrical vessel control signal. The vessel control signal is generated in any one of many known ways, such as by translating a mechanical movement of a wheel or lever into a corresponding electrical signal through a potentiometer. Digital techniques as well as analog techniques are available for providing the vessel control signal and are within the scope of this disclosure. 
     The vessel control signal is delivered to a control processor unit  130  which comprises at least one processor adapted for generating a plurality of actuator control signals from the vessel control signal. The electrical lines  132  are input lines carrying vessel control signals from the respective vessel control apparatus  100 ,  110  and  120 . The control processor unit  130  may also comprise a storage member that stores information using any suitable technology. For example, a data table holding data corresponding to equipment calibration parameters and set points can be stored in a magnetic, electrostatic, optical, or any other type of unit within the control processor unit  130 . 
     Other input signals and output signals of the control processor unit  130  include output lines  136 , which carry control signals to control electrically-controlled actuator control valve  140 . Also, control processor unit  130  receives input signals on lines  134  from any signals of the control system to indicate a position or status of that part. These input signals may be used as a feedback in some embodiments to facilitate the operation of the system or to provide an indication to the operator or another system indicative of the position or status of that part. 
       FIG. 4  illustrates another exemplary embodiment of a dual jet driven propulsion and control system for a marine vessel and is similar to  FIG. 3  except that the system is controlled with only a helm  120  and a control stick  100 . It is to be appreciated that throughout this description like parts have been labeled with like reference numbers, and a description of each part is not always repeated for the sake of brevity. For this embodiment, the functions of the throttle controller  110  of  FIG. 3  are subsumed in the functions of the control stick  100 . Outputs  133  “To Engine” allow for control of the input RPM of pumps  150 P and  150 S. In some embodiments, the steering nozzles  158  may be controlled from the control stick  100  as well. 
       FIG. 5  illustrates an example of a control device and associated actuator. A waterjet stream is produced at the outlet of a waterjet pump as described earlier, or is generated using any other water-drive apparatus. A waterjet propulsion system moves a waterjet stream  3101  pumped by a pump (also referred to herein as a propulsor, or a means for propelling water to create the waterjet) through waterjet housing  3132  and out the aft end of the propulsion system through an articulated steering nozzle  3102 . 
     The fact that the steering nozzle  3102  is articulated to move side-to-side will be explained below, but this nozzle  3102  may also be fixed or have another configuration as used in various applications. The waterjet stream exiting the steering nozzle  3102  is designated as  3101 A. 
       FIG. 5  also illustrates a laterally-fixed reversing bucket  3104  and trim deflector  3120  positioned to allow the waterjet stream to flow freely from  3101  to  3101 A, thus providing forward thrust for the marine vessel. The forward thrust results from the flow of the water in a direction substantially opposite to the direction of the thrust. Trim deflector  3120  is fixably attached to reversing deflector  3104  in this embodiment, and both the reversing deflector  3104  and the trim deflector  3120  rotate in unison about a pivot  3130 . 
     Other embodiments of a reversing deflector and trim deflector for a waterjet propulsion system are illustrated in commonly-owned, co-pending U.S. patent application, Ser. No. 10/213,829, which is hereby incorporated by reference in its entirety. 
     The apparatus for moving the integral reversing deflector and trim deflector comprises a hydraulic actuator  3106 , comprising a hydraulic cylinder  3106 A in which travels a piston and a shaft  3106 B attached to a pivoting clevis  3106 C. Shaft  3106 B slides in and out of cylinder  3106 A, causing a corresponding raising or lowering of the integral reversing deflector and trim deflector apparatus  3700 , respectively. 
     It can be appreciated from  FIG. 5  that progressively lowering the reversing deflector will provide progressively more backing thrust, until the reversing deflector is placed fully in the exit stream  3101 A, and full reversing or backing thrust is developed. In this position, trim deflector  3120  is lowered below and out of the exit stream  3101 A, and provides no trimming force. 
     Similarly, if the combined reversing deflector and trim deflector apparatus  3700  is rotated upwards about pivot  3130  (counter clockwise in  FIG. 5 ) then the trim deflector  3120  will progressively enter the exiting water stream  3101 A, progressively providing more trimming force. In such a configuration, the reversing deflector  3104  will be raised above and out of waterjet exit stream  3101 A, and reversing deflector  3104  will provide no force. 
     However, it is to be understood that various modifications to the arrangement, shape and geometry, the angle of attachment of the reversing deflector  3104  and the trim deflector  3120  and the size of the reversing deflector  3104  and trim deflector  3120  are possible, as described for example in co-pending U.S. patent application, Ser. No. 10/213,829. It is also to be appreciated that although such arrangements are not expressly described herein for all embodiments, but that such modifications are nonetheless intended to be within the scope of this disclosure. 
     Steering nozzle  3102  is illustrated in  FIG. 5  to be capable of pivoting about a trunion or a set of pivots  3131  using a hydraulic actuator. Steering nozzle  102  may be articulated in such a manner as to provide side-to-side force applied at the waterjet by rotating the steering nozzle  3102 , thereby developing the corresponding sideways force that steers the marine vessel. This mechanism works even when the reversing deflector  3104  is fully deployed, as the deflected water flow will travel through the port and/or starboard sides of the reversing deflector  3104 . Additionally, the steering nozzle  3102  can deflect side-to-side when the trim deflector  3120  is fully deployed. 
       FIG. 6  illustrates an exemplary control system diagram for a single waterjet driven marine vessel having one associated steering nozzle and one associated reversing bucket as well as a bow thruster  200 . The diagram illustrates a vessel control stick  100  (joystick) and a helm  120  connected to provide vessel control signals to a control processor unit  130  (control box). The vessel control unit  130  provides actuator control signals to a number of devices and actuators and receives feedback signals from a number of actuators and devices. The figure only illustrates a few such actuators and devices, with the understanding that complete control of a marine vessel is a complex procedure that can involve any number of control apparatus (not illustrated) and depends on a number of operating conditions and design factors. Note that the figure is an exemplary cabling diagram, and as such, some lines are shown joined to indicate that they share a common cable, in this embodiment, and not to indicate that they are branched or carry the same signals. 
     One output signal of the control processor unit  130  is provided, on line  141 A, to a reversing bucket proportional solenoid valve  140 A. The bucket proportional solenoid valve  140 A has coils, indicated by “a” and “b” that control the hydraulic valve ports to move fluid through hydraulic lines  147 A to and from reversing bucket actuator  152 . The reversing bucket actuator  152  can retract or extend to move the reversing bucket  154  up or down to appropriately redirect the waterjet stream and provide forward or reversing thrust. 
     Another output of the control processor unit  130 , on line  141 B, is provided to the nozzle proportional valve  140 B. The nozzle proportional valve  140 B has coils, indicated by “a” and “b” that control the hydraulic valve ports to move fluid through hydraulic lines  147 B to and from nozzle actuator  153 . The nozzle actuator  153  can retract or extend to move the nozzle  158  from side to side control the waterjet stream and provide a turning force. 
     Additionally, an output on line  203  of the control processor unit  130  provides an actuator control signal to control a prime mover, or engine  202 . As stated earlier, an actuator may be any device or element able to actuate or set an actuated device. Here the engine&#39;s rotation speed (RPM) or another aspect of engine power or throughput may be so controlled using a throttle device, which may comprise any of a mechanical, e.g. hydraulic, pneumatic, or electrical device, or combinations thereof. 
     Also, a bow thruster  200  (sometimes referred to merely as a “thruster”) is controlled by actuator control signal provided on output line  201  by the control processor unit  130 . The actuator control signal on line  201  is provided to a bow thruster actuator to control the bow thruster  200 . Again, the bow thruster actuator may be of any suitable form to translate the actuator control signal on line  201  into a corresponding movement or action or state of the bow thruster  200 . Examples of thruster actions include speed of rotation of an impeller and/or direction of rotation of the impeller. 
     According to an aspect of some embodiments of the control system, an autopilot  138 , as known to those skilled in the art, can provide a vessel control signal  137  to the control processor unit  130 , which can be used to determine actuator control signals. For example, the autopilot  138  can be used to maintain a heading or a speed. It is to be appreciated that the autopilot  138  can also be integrated with the control processor unit  130  and that the control processor unit  130  can also be programmed to comprise the autopilot  138 . 
       FIG. 7  illustrates a control system for a marine vessel having two waterjets, two nozzles,  158 P and  158 S, and two reversing buckets,  152 P and  152 S. The operation of this system is similar to that of  FIG. 6 , and like parts have been illustrated with like reference numbers and a description of such parts is omitted for the sake of brevity. However, this embodiment of the control processor unit  130  generates more output actuator control signals based on the input vessel control signals received from vessel control apparatus  100  and  120 . Specifically, the operation of a vessel having two or more waterjets, nozzles, reversing buckets, etc. use a different set of algorithms, for example, stored within control processor unit  130 , for calculating or generating the output actuator control signals provided by the control processor unit  130 . Such algorithms can take into account the design of the vessel, and the number and arrangement of the control surfaces and propulsion apparatus. 
     We now look at a more detailed view of the nature of the signals provided to and produced by the control processor unit  130 .  FIG. 8  illustrates a portion of a control processor unit  130 A with a dashed outline, symbolically representing an exemplary set of signals and functions processed and provided by the control processor unit  130  for a marine vessel having a single waterjet propulsor apparatus. As described earlier, the control processor unit receives one or more input signals from one or more vessel control apparatus, e.g.,  100 ,  110 , and  120 . 
     Control stick  100  is a joystick-type vessel control apparatus, having two degrees of freedom (x and y) which provide corresponding output vessel control signals VCx and VCy. Each of the vessel control signals VCx and VCy can be split into more than one branch, e.g. VCx 1 , VCx 2  and VCx 3 , depending on how many functions are to be carried out and how many actuators are to be controlled with each of the vessel control signals VCx and VCy. 
     The helm  120  is a vessel control apparatus and has one degree of freedom and produces a vessel control signal VCh corresponding to motion of the helm wheel along a rotary degree of freedom (clockwise or counter-clockwise). 
     Throttle control  110  is a vessel control apparatus and has one degree of freedom and produces a vessel control signal VCt corresponding to motion of the throttle control  110  along a linear degree of freedom. 
     According to one aspect of the invention, each vessel control signal is provided to the control processor unit  130  and is used to produce at least one corresponding actuator control signal. Sometimes more than one vessel control signal are processed by control processor unit  130  to produce an actuator control signal. 
     According to the embodiment illustrated in  FIG. 8 , the x-axis vessel control signal VCx provided by the control stick  100  is split to control three separate device actuators: a bow thruster actuator, a prime mover engine RPM actuator and a waterjet nozzle position actuator (devices and actuators not shown). The vessel control signal VCx is split into three vessel control branch signals, VCx 1 , VCx 2  and VCx 3 . The branch signals can be thought of as actually splitting up by a common connection from the main vessel control signal VCx or derived in some other way that allows the vessel control signal VCx to be used three times. Vessel control branch signal VCx 1  is equal to the vessel control signal VCx and is input to a bow thruster RPM and direction module  180  that is adapted for calculating actuator signal AC 1  to control the RPM and direction of motion of the bow thruster. In one embodiment of the bow thruster RPM and direction module  180 , processor module  130 A is provided with a look-up table (LUT) which determines the end-points of the functional relationship between the input vessel control branch signal VCx 1  and the output actuator control signal AC 1 . 
     Processor module  130 A may be one of several processing modules that comprise the control processor unit  130 . Many other functions, such as incorporation of a feedback signal from one or more actuators can be performed by the processors  130 ,  130 A as well. The signals shown to exit the processor module  130 A are only illustrative and may be included with other signals to be processed in some way prior to delivery to an actuator. Note that in some embodiments of the processor module  130 A there is no difference, or substantially no difference, between the vessel control signal VCx and the associated vessel control branch signals (e.g., VCx 1 , VCx 2  and VCx 3 ), and they will all be generally referred to herein as vessel control signals. One of skill in the art would envision that the exact signals input into the function modules of a control processor unit can be taken directly from the corresponding vessel control apparatus, or could be pre-processed in some way, for example by scaling through an amplifier or by converting to or from any of a digital signal and an analog signal using a digital-to-analog or an analog-to-digital converter. 
     While various embodiments described herein present particular implementations of the control processor unit  130  and the various associated modules which functionally convert input vessel control signals to actuator control signal outputs, it should be understood that the invention is not limited to these illustrative embodiments. For example, the modules and control processor unit  130  may be implemented as a processor comprising semiconductor hardware logic which executes stored software instructions. Also, the processor and modules may be implemented in specialty (application specific) integrated circuits ASICs, which may be constructed on a semiconductor chip. Furthermore, these systems may be implemented in hardware and/or software which carries out a programmed set of instructions as known to those skilled in the art. 
     The waterjet prime mover (engine) RPM is controlled in the following way. Vessel control branch signal VCx 2 , which is substantially equal to the vessel control signal VCx is provided to engine RPM module  181  that is adapted for calculating a signal AC 21 . In addition, vessel control signal VCy is used to obtain vessel control branch signal VCy 1  that is provided to engine RPM module  183 , which determines and provides an output signal AC 22 . Further, throttle control apparatus  110 , provides vessel control signal VCt, that is provided to engine RPM module  186  that determines and provides an output signal AC 23 . The three signals AC 21 , AC 22  and AC 23  are provided to a selector  170  that selects the highest of the three signals. The highest of AC 21 , AC 22  and AC 23  is provided as the actuator control signal AC 2  that controls the engine RPM. It is to be appreciated that, although engine RPM modules  181 ,  183  and  186  have been illustrated as separate modules, they can be implemented as one module programmed to perform all three functions, such as a processor programmed according to the three illustrated functions. 
     It should also be pointed out that the system described above is only exemplary. Other techniques for selecting or calculating actuator control signal AC 2  are possible. For example, it is also possible to determine averages or weighted averages of input signals, or use other or additional input signals, such as feedback signals to produce AC 2 . It is also to be appreciated that, depending on the desired vessel dynamics and vessel design, other function modules and selectors may be implemented within control processor unit  130  as well. 
     As mentioned above, control stick  100  produces vessel control signal VCy when the control stick  100  is moved along the y-direction degree of freedom as previously mentioned. According to another aspect of this embodiment, reversing bucket position module  184  receives vessel control signal VCy and calculates the actuator control signal AC 3 . The signal AC 3  is provided to the reversing bucket actuator (not shown). Signal AC 3  may be an input to a closed-loop position control circuit wherein signal AC 3  corresponds to a commanded position of the reversing bucket actuator, provided directly or indirectly, to cause the reversing bucket to be raised and lowered, as described earlier. Reference is made to  FIG. 6 , in which signals  134 A and  134 B are feedback signals from the reversing bucket actuator  152  and the nozzle actuator  153 , respectively. More detailed descriptions of the construction and operation of closed-loop feedback circuits in marine vessel control systems are provided in the patent applications referenced earlier in this section, which are hereby incorporated by reference. 
     According to another aspect of the invention, input signals are taken from each of the control stick  100  and the helm  120  to operate and control the position of the waterjet nozzle (not shown). Vessel control signals VCx 3  and VCh are provided to nozzle position modules  182  and  186 , which generate signals AC 41  and AC 42  respectively. The signals AC 41  and AC 42  are summed in a summing module  172  to produce the nozzle position actuator control signal AC 4 . Note that the summing module  172  can be replaced with an equivalent or other function, depending on the application. 
     The previous discussion has illustrated that algorithms can be implemented within the control processor unit  130 , and is in some embodiments carried out using function modules. This description is conceptual and should be interpreted generally, as those skilled in the art recognize the possibility of implementing such a processing unit in a number of ways. These include implementation using a digital microprocessor that receives the input vessel control signals or vessel control branch signals and performs a calculation using the vessel control signals to produce the corresponding output signals or actuator control signals. Also, analog computers may be used which comprise circuit elements arranged to produce the desired outputs. Furthermore, look-up tables containing any or all of the relevant data points may be stored in any fashion to provide the desired output corresponding to an input signal. 
     Key data points on the plots of the various functions relating the inputs and outputs of the function modules are indicated with various symbols, e.g. solid circles, plus signs and circles containing plus signs. These represent different modes of calibration and setting up of the functions and will be explained below. 
     Specific examples of the algorithms for generating the previously-described actuator control signals for single-waterjet vessels are given in  FIGS. 9A-9C, 10A-10B and 11A-11B . 
       FIG. 9( a )  illustrates the bow thruster RPM and direction module  180 , the engine RPM module  181 , and the nozzle position module  182  in further detail. Each of these modules receives as an input signals due to motion of the control stick  100  along the x-direction or x-axis. As mentioned before, such motion generates a vessel control signal VCx that is split into three signals VCxl, VCx 2  and VCx 3 . The thruster RPM and direction of thrust module  180  converts vessel control branch signal VCxl into a corresponding actuator control signal ACl. According to one embodiment of the invention, module  180  provides a linear relationship between the input VCxl and the output AC 1 . The horizontal axis shows the value of VCxl with a neutral (zero) position at the center with port being to the left of center and starboard (“STBD”) being to the right of center in the figure. An operator moving the control stick  100  to port will cause an output to generate a control signal to drive the bow thruster in a to-port direction. The amount of thrust generated by the bow thruster  200  (see  FIG. 6 ) is dictated in part by the bow thruster actuator and is according to the magnitude of the actuator control signal ACl along the y-axis in module  180 . Thus, when no deflection of the control stick  100  is provided, zero thrust is generated by the bow thruster  200 . Operation to-starboard is analogous to that described above in regard to the to-port movement. 
     It is to be appreciated that the bow thruster  200  can be implemented in a number of ways. The bow thruster  200  can be of variable speed and direction or can be of constant speed and variable direction. The bow thruster  200  may also be an electrically-driven propulsor whose speed and direction of rotation are controlled by a signal which is proportional to or equal to actuator control signal AC 1 . The precise form of this function is determined by preset configuration points typically set at the factory 
       FIG. 9( b )  illustrates the relationship between waterjet prime mover engine RPM and the vessel control signal VCx 2 , according to one embodiment of the invention. Engine RPM module  181  receives vessel control signal (or branch signal) VCx 2  and uses a group of pre-set data points relating the vessel control signal inputs to actuator control signal outputs to compute a response. Simply put, for control stick  100  movements near the neutral x=0 center position, engine RPM control module provides an engine RPM control signal having an amplitude that is minimal, and consists of approximately idling the engine at its minimal value. According to an aspect of this embodiment, this may be true for some interval of the range of the control stick  100  in the x-direction about the center position as shown in the figure, or may be only true for a point at or near the center position. 
     The figure also shows that, according to this embodiment of the module  181 , moving the control stick  100  to its full port or full starboard position generates the respective relative maximum engine RPM actuator control signal AC 21 . While the figure shows the port and starboard signals as symmetrical, they may be asymmetrical to some extent if dictated by some design or operational constraint that so makes the vessel or its auxiliary equipment or load asymmetrical with respect to the x-axis. The precise form of this function is determined by preset configuration points typically set at the factory or upon installation. 
       FIG. 9( c )  illustrates the relation between the vessel control signal VCx 3  and the discharge nozzle position according to one embodiment of the invention. Nozzle position module  182  generates an output actuator control signal AC 41  based on the x-axis position of the control stick  100 . The nozzle actuator (not shown) moves the nozzle in the port direction in proportion to an amount of deflection of the control stick  100  along the x-axis in the port direction and moves the nozzle in the starboard direction in proportion to an amount of deflection of the control stick  100  along the x-axis in the starboard direction. The precise function and fixed points therein are calibrated based on an optimum settings procedure and may be performed dock-side by the operator or underway, as will be described in more detail below. 
       FIGS. 10( a, b )  illustrate the engine RPM module  183  and the bucket position module  184  in further detail. Each of these modules receives an input signal VCy taken from the control stick  100  when moved along the y-direction.  FIG. 10( a )  illustrates a vessel control branch signal VCy 1  which is provided to engine RPM module  183 , which in turn computes an output signal AC 22 . Said output signal AC 22  provides a control signal AC 2  to the waterjet engine RPM actuator (not shown). Signal AC 22  is combined with other signals, as discussed earlier, to provide the actual actuator control signal AC 2 . According to this embodiment of the engine RPM module, the engine RPM is set to a low (idle) speed at or around the y=0 control stick position. Also, the extreme y-positions of the control stick result in relative maxima of the engine RPM. It should be pointed out that in this embodiment this function is not symmetrical about the y=0 position, due to a loss of efficiency with the reversing bucket deployed, and depends upon calibration of the system at the factory. 
       FIG. 10( b )  illustrates the effect of control stick  100  movement along the y-axis on the reversing bucket position, according to one embodiment of the invention. A vessel control signal VCy 2  is plotted on the horizontal axis depicting module  184 . When moved to the “back” or aft position, actuator control signal AC 3 , provided by module  184 , causes a full-down movement of the reversing bucket  154  (not shown), thus providing reversing thrust. When the control stick  100  is moved fully forward in the y-direction, actuator control signal AC 3  causes a full-up movement of the reversing bucket  154 . According to this embodiment, the reversing bucket  154  reaches its maximum up or down positions prior to reaching the full extreme range of motion in the y-direction of the control stick  100 . These “shoulder points” are indicated for the up and down positions by numerals  184 A and  184 B, respectively. The piecewise linear range between points  184 A and  184 B approximately coincide with the idle RPM range of module  183 . This allows for fine thrust adjustments around the neutral bucket position while higher thrust values in the ahead and astern directions are achieved by increasing the engine RPM when the control stick is moved outside of the shoulder points. It can be seen that in this and other exemplary embodiments the center y-axis position of control stick  100  is not necessarily associated with a zero or neutral reversing bucket position. In the case of the embodiment illustrated in  FIG. 10( b ) , the zero y-axis position corresponds to a slightly down position  184 C of the reversing bucket  154 . 
       FIG. 11( a )  illustrates the nozzle position function module  185  in further detail. This module receives an input from the vessel control signal VCh and provides as output the actuator control signal AC 42 . Nozzle position function module  185  determines output signal AC 42  to be used in the control of the waterjet discharge nozzle  158  (not shown). The signal AC 42  can be used as one of several components that are used to determine actuator control signal AC 4 , or, in some embodiments, can be used itself as the actuator control signal AC 4 . This embodiment of the nozzle position function module  185  has a linear relationship between the input signal VCh, received from the helm  120 , and the output signal AC 42 , which can be determined by underway or dock-side auto calibration to select the end points of the linear function. Intermediate values can be computed using known functional relationships for lines or by interpolation from the two end points. Other embodiments are also possible and will be clear to those skilled in the art. 
       FIG. 11( b )  illustrates the engine RPM function module  186  in further detail. The figure also illustrates the relationship between the throttle controller signal VCt and the engine RPM actuator signal AC 23 . As before, a vessel control signal VCt is taken from the vessel control apparatus (throttle controller)  110 . The function module  186  converts the input signal VCt into an output signal AC 23  which is used to determine the engine RPM actuator control signal AC 2 . In some embodiments, the throttle controller  110  has a full back position, which sends a signal to the engine RPM actuator to merely idle the engine at its lowest speed. At the other extreme, when the throttle controller  110  is in the full-ahead position, the engine RPM function module  186  provides a signal to the engine RPM actuator, which is instructed to deliver maximum engine revolutions. Note that according to one embodiment of the invention, the exact points on this curve are calibrated at the factory and are used in conjunction with other vessel control inputs to determine the final control signal that is sent to the engine RPM actuator AC 2 , as shown in  FIG. 8 . 
     In some embodiments, key points used in the plurality of functional modules are either pre-programmed at manufacture, or are selected and stored based on a dock-side or underway calibration procedure. In other embodiments, the key points may be used as parameters in computing the functional relationships, e.g. using polynomials with coefficients, or are the end-points of a line segment which are used to interpolate and determine the appropriate function output. 
     According to this embodiment of the control system, single waterjet vessel control is provided, as illustrated in  FIGS. 12A-12D . By way of example, three exemplary motions of the helm  120 , and five exemplary motions of the control stick  100  are shown. The control stick  100  has two degrees of freedom (x and y). It is to be appreciated that numerous other helm  120  and control stick  100  positions are possible but are not illustrated for the sake of brevity. The figure shows the helm in the turn-to-port, in the ahead (no turning) and in the turn-to-starboard positions in the respective columns of the figure. The helm  120  can of course be turned to other positions than those shown. 
       FIG. 12( a )  illustrates that if the control stick  100  is placed in the full ahead position and the helm  120  is turned to port then the vessel will turn to port. Because the control stick is in the +y position, and not moved along the x-direction, the bow thruster  200  is off (see  FIG. 9( a ) ), the engine RPM is high (see  FIG. 10( a ) , heavy waterjet flow is shown aft of vessel in  FIG. 12( a ) ) and the reversing bucket is raised (see  FIG. 10( b ) ). Engine RPM is high because the highest signal is selected by selector module  170 . Because the helm is in the turn-to-port position (counter-clockwise) the steering nozzle  158  is in the turn-to-port direction (see  FIG. 11( a ) ). It is to be appreciated that no separate throttle controller  110  is used or needed in this example. As illustrated in  FIG. 12( a ) , the vessel moves along a curved path with some turning radius, as the helm control is turned. 
     Similarly, according to some control maneuvers, by placing the helm  120  in the straight ahead position while the control stick  100  is in the full ahead position, the vessel moves ahead in a straight line at high engine RPM with the reversing bucket  154  raised and the nozzle in the centered position. Helm  120  motion to starboard is also illustrated and is analogous to that as its motion to port and will not be described for the sake of brevity. 
       FIG. 12( b )  illustrates operation of the vessel when the control stick  100  is placed in a neutral center position. When the helm  120  is turned to port, the steering nozzle  158  is in the turn-to-port position (see  FIG. 11( a ) ) and the engine  200  is idle because the selector module  170  selects the highest RPM signal, which will be according to signal AC 21  provided from engine RPM function module  181  (see  FIG. 9( b )  where no throttle is applied). The reversing bucket  154  is approximately in a neutral position that allows some forward thrust and reverses some of the waterjet stream to provide some reversing thrust. (see  FIG. 10( b ) ). This reversing flow is deflected by the reversing bucket  154  to the left. The vessel substantially rotates about a vertical axis while experiencing little or no lateral or ahead/astern translation. 
     According to some maneuvers, by placing the helm  120  in the straight ahead position no motion of the vessel results. That is, no turning occurs, and the forward and backing thrusts are balanced by having the engine at low RPM and the reversing bucket  154  substantially in a neutral position. The reversed waterjet portion is split between the left and the right directions and results in no net force athwartships. Thus, no vessel movement occurs. Helm  120  motion to starboard is also illustrated and is analogous to that of port motion and is not described for the sake of brevity. 
       FIG. 12( c )  illustrates vessel movement when the control stick  100  is moved to port. With the helm  120  in a counter-clockwise (port) position, the bow thruster  200  provides thrust to port (see  FIG. 9( a ) ), the steering nozzle  158  is in the turn-to-port position (see  FIG. 9( c ) ) and the engine RPM is at a high speed (see  FIG. 9( b ) ). Again, the precise actuator control signals depend on the function modules, such as summing module  172 , which sums signals from function modules  182  and  185 . With the reversing bucket sending slightly more flow to the right than to the left, the vessel translates to the left and also rotates about a vertical axis. The engine RPM is high because selector module  170  selects the highest of three signals 
     Similarly, the helm  120  can be placed in the straight ahead position, which results in the nozzle being to the right and the reversing bucket  154  in a middle (neutral) position. The bow thruster  200  also thrusts to port (by ejecting water to starboard). The net lateral thrust developed by the bow thruster  200  and that developed laterally by the waterjet are equal, so that the vessel translates purely to the left without turning about a vertical axis. 
       FIGS. 12A-12D  also illustrate vessel movement with the control stick  100  moved to starboard for three positions of the helm  120 . The resultant vessel movement is analogous to that movement described for motion in the port direction and is not herein described for the sake of brevity. 
       FIG. 12( d )  illustrates vessel movement when the control stick  100  is placed in the backing (−y) direction. When the helm  120  is turned to port, the bow thruster  200  is off (x=0, see  FIG. 9( a ) ), the engine RPM is high (see  FIG. 10( a ) —the highest signal is selected by selector  170 ), the reversing bucket  154  is in the full down position (see  FIG. 10( b ) ) and deflects the flow to the left, and the nozzle is in the turn-to-port position (see  FIG. 11( a ) ). The vessel moves in a curved trajectory backwards and to the right. 
     Similarly, according to some control modules, by placing the helm  120  in the straight ahead position, the reversing bucket  154  remains fully lowered but the nozzle is in the neutral position, so the reversing bucket deflects equal amounts of water to the right and to the left because the nozzle is centered. The bow thruster  200  remains off. Thus, the vessel moves straight back without turning or rotating. Helm  120  motion to starboard is also illustrated and is analogous to that for motion to port and thus will not be described herein. 
     It should be appreciated that the above examples of vessel movement are “compound movements” that in many cases use the cooperative movement of more than one device (e.g., propulsors, nozzles, thrusters, deflectors, reversing buckets) of different types. It is clear, e.g. from  FIGS. 12( c, d )  that, even if only one single vessel control signal is provided (e.g., −y) of the control stick  100  along a degree of freedom of the control stick  100 , a plurality of affiliated actuator control signals are generated by the control system and give the vessel its overall movement response. This is true even without movement of the helm  120  from its neutral position. 
     It should also be appreciated that in some embodiments the overall movement of the vessel is in close and intuitive correspondence to the movement of the vessel control apparatus that causes the vessel movement. Some embodiments of the present invention can be especially useful in maneuvers like docking. 
     It should also be appreciated that the algorithms, examples of which were given above for the vessel having a single waterjet propulsor, can be modified to achieve specific final results. Also, the algorithms can use key model points from which the response of the function modules can be calculated. These key model points may be pre-assigned and pre-programmed into a memory on the control processor unit  130  or may be collected from actual use or by performing dock-side or underway calibration tests, as will be described below. 
     It should be further appreciated that the single waterjet comprising a single nozzle and single reversing bucket described in  FIGS. 8, 9A-9C, 10A-10B, 11A-11B, 12A-12D  can be modified to drive a marine vessel with two waterjets comprising two nozzles and two reversing buckets as shown in  FIGS. 32A-32B . It is to be understood that  FIGS. 32A-32B  had many of the same components as  FIG. 8 , that these components have been numbered with either identical or similar reference numbers and that the description of each of the components of  FIGS. 32A-B  has not been duplicated here for the sake of brevity. It is also to be appreciated that although there is no throttle  110  illustrated in  FIGS. 32A-B  (See  FIG. 8 ), that such a throttle can be part of the control system, as well as other controllers used in the art. In addition, it is to be appreciated that any or all of the joystick  100 , helm  120 , and throttle  110 , can be replaced with an interface to a remote control system that receives any or all of control signals such as any or all of net transverse translational thrust commands, net forward or reverse translational thrust commands, and net rotational thrust commands, and which can combine and translate these signals into either or both of a net translational and/or net rotational thrust commands. In the embodiment of  FIGS. 32A-B , the output of the nozzle position module  185  is split into two signals AC 4   a  and AC 4   b , which drive the port and starboard nozzles. Similarly, the output of the bucket position module  184  is split into two signals AC 3   a  and AC 3   b , which drive the port and starboard bucket positions. Similarly, the output of the engine rpm module  183  and selector  170 , which selects the highest signal, is split into two signals AC 2   a  and AC 2   b , which drive the port and starboard engines. With such an arrangement, there is provided a control system for a marine vessel having a bow thruster and two waterjets comprising two nozzles and two reversing buckets. It should also be appreciated that the two waterjets can be replaced with three or more waterjets comprising corresponding nozzles and reversing buckets, and controlled in a similar fashion by splitting the Signals AC 2 , AC 3 , and AC 4  into a like number of signals. 
     As mentioned previously and as illustrated, e.g., in  FIG. 3 , a marine vessel may have two or more waterjet propulsors, e.g.  150 P and no bow thruster. A common configuration is to have a pair of two waterjet propulsors, each having its own individually controlled prime mover, pump, reversing bucket, and steering nozzle, e.g.,  158 . A reversing bucket, e.g.  154 , is coupled to each propulsor  150 P as well, and the reversing buckets, e.g.  154 , may be of a type fixed to the steering nozzle and rotating therewith (not true for the embodiment of  FIG. 3 ), or they may be fixed to a waterjet housing or other part that does not rotate with the steering nozzles  158  (as in the embodiment of  FIG. 3 ). 
     The following description is for marine vessels having two propulsors and no bow thruster, and can be generalized to more than two propulsors, including configurations that have different types of propulsors, such as variable-pitch propellers or other waterjet drives. 
       FIG. 13A  illustrates a signal diagram for an exemplary vessel control system controlling a set of two waterjet propulsors and associated nozzles and reversing buckets. This example does not use a bow thruster for maneuvering as in the previous example having only one waterjet propulsor, given in  FIG. 8 . 
     Control stick  100  has two degrees of freedom, x and y, and produces two corresponding vessel control signals  1000  and  1020 , respectively. The vessel control signals  1000  and  1020  are fed to several function modules through branch signals as discussed earlier with regard to  FIG. 8 . In the following discussion of  FIG. 13A  it should be appreciated that more than one vessel control signal can be combined to provide an actuator control signal, in which case the individual vessel control signals may be input to the same function modules or may each be provided to an individual function module. In the figure, and in the following discussion, there are illustrated separate function modules for each vessel control signal, for the sake of clarity. Note that in the event that more than one signal is used to generate an actuator control signal, a post-processing functional module, such as a summer, a selector or an averaging module is used to combine the input signals into an output actuator control signal. 
     The x-axis vessel control signal  1000  provides an input to each of six function modules: function module  1700 , which calculates a signal  1010 , used in controlling the port reversing bucket position actuator; function module  1701 , which calculates a signal  1011 , used in controlling the port engine RPM actuator; function module  1702 , which calculates a signal  1012 , used in controlling the port nozzle position actuator; function module  1703 , which calculates a signal  1013 , used in controlling the starboard reversing bucket position actuator; function module  1704 , which calculates a signal  1014 , used in controlling the starboard engine RPM actuator; and function module  1705 , which calculates a signal  1015 , used in controlling the starboard nozzle position actuator. 
     Note that some of the signals output from the function modules are the actuator control signals themselves, while others are used as inputs combined with additional inputs to determine the actual actuator control signals. For example, the port and starboard engine RPM actuators receive a highest input signal from a plurality of input signals provided to selector modules  1140 ,  1141 , as an actuator control signal for that engine RPM actuator. 
     The y-axis vessel control signal  1020  provides an input to each of four function modules: function module  1706 , which calculates a signal  1016 , used in controlling the port engine RPM actuator; function module  1707 , which calculates a signal  1017 , used in controlling the port reversing bucket position actuator; function module  1708 , which calculates a signal  1018 , used in controlling the starboard engine RPM actuator; and function module  1709 , which calculates a signal  1019 , used in controlling the starboard reversing bucket position actuator. 
     Helm vessel control apparatus  120  delivers a vessel control signal to each of two function modules: function module  1710 , which calculates a signal  1020 , used in controlling the port nozzle position actuator and function module  1711 , which calculates a signal  1021 , used in controlling the starboard nozzle position actuator. 
     Two separate throttle control apparatus are provided in the present embodiment. A port throttle controller  110 P, which provides a vessel control signal  1040  as an input to function module  1712 . Function module  1712  calculates an output signal  1022 , based on the vessel control signal  1040 , that controls the engine RPM of the port propulsor. Similarly, a starboard throttle controller  110 S, provides a vessel control signal  1041  as an input to function module  1713 . Function module  1713  calculates an output signal  1023 , based on the vessel control signal  1041 , that controls the engine RPM of the starboard propulsor. 
     As mentioned before, more than one intermediate signal from the function modules or elsewhere can be used in combination to obtain the signal that actually controls an actuator. Here, a selector module  1140  selects a highest of three input signals,  1011 ,  1016  and  1022  to obtain the port engine RPM actuator control signal  1050 . A similar selector module  1141  selects a highest of three input signals,  1014 ,  1018  and  1023  to obtain the starboard engine RPM actuator control signal  1051 . 
     Additionally, a summation module  1142  sums the two input signals  1010  and  1017  to obtain the port reversing bucket position actuator control signal  1052 . Another summation module  1143  sums the two input signals  1013  and  1019  to obtain the starboard reversing bucket position actuator control signal  1053 . Yet another summation module  1144  sums the two input signals  1012  and  1020  to obtain the port nozzle position actuator control signal  1054 , and summation module  1145  sums the two input signals  1015  and  1021  to obtain the starboard nozzle position actuator control signal  1055 . 
       FIG. 13B  illustrates a signal diagram of another embodiment of a marine vessel control system for a dual waterjet vessel. In this embodiment, the reversing bucket position (port and starboard reversing buckets) is configured by modules  1700 ,  1703  with respect to movement of the joystick  100  in the X-axis to two discrete positions, fully up and fully down. The output signals of these  1700 ,  1703  modules, which correspond to bucket position when commanding a translational thrust with a side component, is fed to selector modules  2142 ,  12143 , on lines  1010  and  1013 , which select between these signals and the signals from port and starboard bucket position modules  1707 ,  1709 , which correspond to bucket when commanding only a fore-aft translational thrust (no side component). The selector module selects between these input signals to outputs port and starboard bucket actuator signals on lines  1052 ,  1053 , based on whether there is a translational thrust command with a side component or no side component. In particular, the selection module provides the output signals which are the signals on lines  1010  and  1013  when there is a side component and the signals on lines  1017  and  1019  when there is no side component. In addition, the engine rpm for the port and starboard engines are varied, by port engine rpm module  1701  and starboard engine rpm module  1704 , to vary proportionally with respect to the x-axis. Referring to  FIGS. 13E-F , this embodiment has an advantage in that the for-aft thrust component (the engine RPM&#39;s) can be modulated (varied for example from full thrust as illustrated in  FIG. 13E  to half thrust as illustrated in  FIG. 13F ) with the reversing bucket at a fixed position, such as full up position, and the nozzle(s) at an angle Θ (presumably required to hold a steady heading of the vessel due to external influences such as water current and/or wind) without effecting the net thrust angle Θ of the waterjet. In contrast, referring to  FIGS. 13C-D , it has been found that for the embodiments where the reversing bucket is also used to assist in varying the thrust of the vessel movement, for example where the reversing bucket is moved from a full up position at full thrust as illustrated in  FIG. 13C , to a half thrust position that includes movement of the reversing bucket as illustrated in  FIG. 13D , the split-flow geometry of the laterally fixed reversing buckets prevents them from modulating the net thrust magnitude of an individual waterjet without affecting the net thrust angle of the waterjet, thereby resulting in some additional net thrust angle +α at the waterjet, resulting in a total net thrust angle of Θ+α at the waterjet. An advantage according to this embodiment, is that by keeping the reversing buckets stationary while modulating engine RPM only (as illustrated in  FIGS. 13E &amp; 13F ), the control system and hence the operator are able to vary the net thrust magnitude applied to the vessel without applying any unwanted rotational force, thereby resulting in movement of the vessel as illustrated in  FIG. 13H . In contrast, referring to  FIG. 13G , it has been found that for the embodiments where the reversing bucket is also used to assist in varying the thrust of the vessel movement, when the net thrust angle changes (as illustrated in  FIG. 13D ), the net rotational moment applied to the vessel is effected. If the vessel is holding a steady heading (no net rotational movement), an unwanted rotational forces applied to the vessel will cause the vessel to rotate when not commanded to do so. This phenomenon is illustrated in  FIG. 13G  which illustrates in particular that the craft is translating to port with no net rotational force (i.e., holding a steady heading) when commanding Full Port thrust. However, when the joystick is moved strictly in the starboard direction to command half port thrust, an unwanted rotational moment is applied to the vessel, causing an uncommanded heading change. 
       FIGS. 13I-A - 13 I-D illustrates a signal diagram of another exemplary marine vessel control system for a dual waterjet vessel. This embodiment of the twin waterjet joystick system is similar to the system described in  FIG. 13B , however, instead of the reversing bucket of the ahead thrusting waterjet moving to the full up position (modules  1700  &amp;  1703 ) when developing transverse thrust as shown in  FIG. 13B , as illustrated in modules  1700 ′ and  1703 ′ the reversing bucket of the ahead thrusting waterjet will move to a position (lower than full up) where the ahead thrust equals the thrust developed by the reverse thrusting waterjet with the reversing bucket in the full down position (with both waterjets at idle RPM). One advantage of operating in this manner is that the reversing waterjet can be maintained at a lower RPM as illustrated in modules  1701 ′ and  1703 ′ and there is no longer a need to step up the RPM of the reversing waterjet at or near the center position as shown, for example, in  FIG. 14E . It is to be appreciated that not all of the elements of  FIGS. 13I-A - 13 I-D have been labeled with reference characters for the sake of simplicity, but that the signal line reference numbers of  FIG. 13B  apply to  FIGS. 13I-A - 13 I-D. 
       FIGS. 14A-C  illustrate, in more detail, the details of the algorithms and functions of  FIG. 13A  used to control the port reversing bucket actuator ( FIG. 14A ), the port engine RPM actuator ( FIG. 14B ) and the port nozzle position actuator ( FIG. 14C ). Three branch vessel control signals  1002 ,  1004  and  1006  branch out of vessel control signal  1000  corresponding to a position of the control stick  100  along the x-axis degree of freedom. The branch vessel control signals  1002 ,  1004  and  1006  are input to respective function modules  1700 ,  1701  and  1702 , and output signals  1010 ,  1011  and  1012  are used to generate respective actuator control signals, as described with respect to  FIG. 13A  above. 
     As described previously, the x-axis degree of freedom of the control stick  100  is used to place the port reversing bucket approximately at the neutral position when the joystick is centered, and motion to starboard will raise the bucket and motion to port will lower the bucket ( FIG. 14A ). The setpoint  1700 A is determined from an underway or free-floating calibration procedure to be the neutral reversing bucket position such that the net thrust along the major axis is substantially zero. Movement of the control stick  100  along the x-axis in the port direction affects nozzle, engine RPM and reversing bucket actuators. Optimum points for the port nozzle position ( FIG. 14C ),  1702 A and  1702 B, are determined by dock-side or underway calibration as in obtaining point  1700 A. Points  1702 A and  1702 B are of different magnitudes due to the geometry of the reversing bucket and different efficiency of the propulsion system when the reversing bucket is deployed compared to when the reversing bucket is not deployed. 
     Port engine RPM is lowest (idling) when the control stick  100  x-axis position is about centered. Port engine RPM is raised to higher levels when the control stick  100  is moved along the x-axis degree of freedom ( FIG. 14B ). The setpoints indicated by the dark circles are set at the factory or configured at installation, based on, e.g., vessel design parameters and specifications. 
       FIGS. 14D-F  illustrate, in more detail, the details of the algorithms and functions of the embodiment of  FIG. 13B  used to control the port reversing bucket actuator ( FIG. 14D ), the port engine RPM actuator ( FIG. 14E ) and the port nozzle position actuator ( FIG. 14F ). As discussed above with respect to  FIGS. 14A-C , three branch vessel control signals  1002 ,  1004  and  1006  branch out of vessel control signal  1000  corresponding to a position of the control stick  100  along the x-axis degree of freedom. The branch vessel control signals  1002 ,  1004  and  1006  are input to respective function modules  1700 ,  1701  and  1702 , and output signals  1010 ,  1011  and  1012  are used to generate respective actuator control signals, as described with respect to  FIG. 13B  above. 
     The x-axis degree of freedom of the control stick  100  is used to place the port reversing bucket approximately at the neutral position when the joystick is centered, motion to starboard outside the deadband will raise the bucket to a single up position, and motion to port will lower the bucket to a single down position ( FIGS. 14A-E ). The setpoint  1700 A can, for example, be determined from an underway or free-floating calibration procedure to be the neutral reversing bucket position such that the net thrust along the major axis is substantially zero. Movement of the control stick  100  along the x-axis in the port direction affects nozzle, engine RPM and reversing bucket actuators, as illustrated. Optimum points for the port nozzle position ( FIG. 14F ),  1702 A and  1702 B, can, for example, be determined by dock-side or underway calibration as in obtaining point  1700 A. Points  1702 A and  1702 B may be of the same magnitude or may be of different magnitudes due to the geometry of the reversing bucket and different efficiency of the propulsion system when the reversing bucket is deployed compared to when the reversing bucket is not deployed. 
     Referring to  FIG. 14E , the port engine RPM is lowest (idling) when the control stick  100  x-axis position is about centered. Port engine RPM is raised to higher levels when the control stick  100  is moved along the X-axis degree of freedom, to in combination with the port bucket position, introduce no rotation movement to the vessel, as discussed above. The setpoints indicated by the dark circles are set at the factory or configured at installation, based on, e.g., vessel design parameters and specifications. According to this embodiment, as illustrated in  FIG. 14E , the port engine RPM can be stepped up abruptly when moved beyond the port threshold of the center dead band, corresponding to the reversing bucket in the full down position. This can be done to compensate for any difference in thrust efficiencies between the reversing bucket in the full up and full down positions. One advantage of having the step only when the waterjet is reversing is that the lower reversing efficiency with the bucket in the full down position is compensated for even with small thrust commands. 
       FIGS. 15A-C , illustrate in more detail the algorithms and functions of the embodiment of the vessel control system of  FIG. 13A , used to control the starboard reversing bucket actuator ( FIG. 15A ), the starboard engine RPM actuator ( FIG. 15B ) and the starboard nozzle position actuator ( FIG. 15C ). The operation of the starboard reversing bucket, the starboard engine rpm, and the starboard nozzle position are similar to that of the port reversing bucket, the port engine rpm and the port nozzle position discussed above with respect to  FIGS. 14A-C . In particular, the three branch vessel control signals  1008 ,  1009  and  1005  branch out of vessel control signal  1000  (in addition to those illustrated in  FIGS. 14A-C , above) corresponding to a position of the control stick  100  along the x-axis degree of freedom. The branch vessel control signals  1008 ,  1009  and  1005  are input to respective function modules  1703 ,  1704  and  1705 , and output signals  1013 ,  1014  and  1015  are used to generate respective actuator control signals, as described with respect to  FIG. 13A , above. The calibration points and functional relationship between the output signals and the vessel control signal are substantially analogous to those described above with respect to  FIGS. 14A-C , and are not discussed in detail again here for the sake of brevity. 
       FIGS. 15D-F , illustrate in more detail the algorithms and functions of the embodiment of the vessel control system of  FIG. 13B , used to control the starboard reversing bucket actuator ( FIG. 15D ), the starboard engine RPM actuator ( FIG. 15E ) and the starboard nozzle position actuator ( FIG. 15F ). The operation of the starboard reversing bucket, the starboard engine rpm, and the starboard nozzle position are similar to that of the port reversing bucket, the port engine rpm and the port nozzle position discussed above with respect to  FIGS. 14D-F . In particular, the three branch vessel control signals  1008 ,  1009  and  1005  branch out of vessel control signal  1000  (in addition to those illustrated in  FIGS. 14D-F , above) corresponding to a position of the control stick  100  along the x-axis degree of freedom. Also as discussed above with respect to  FIG. 14E , according to this embodiment, as illustrated in  FIG. 15E , the port engine RPM can be stepped up abruptly when moved beyond the port threshold of the center dead band, corresponding to the reversing bucket in the full down position. This can be done to compensate for any difference in thrust efficiencies between the reversing bucket in the full up and full down positions. One advantage of having the step only when the waterjet is reversing is that the lower reversing efficiency with the bucket in the full down position is compensated for even with small thrust commands The branch vessel control signals  1008 ,  1009  and  1005  are input to respective function modules  1703 ,  1704  and  1705 , and output signals  1013 ,  1014  and  1015  are used to generate respective actuator control signals, as described with respect to  FIG. 13A , above. The calibration points and functional relationship between the output signals and the vessel control signal are substantially analogous to those described above with respect to  FIGS. 14A-C , and are not discussed in detail again here for the sake of brevity. 
       FIGS. 16A-16  illustrate the algorithms for generating control signals to control the port engine RPM actuator ( FIG. 16( a ) ) and the port reversing bucket position actuator ( FIG. 16( b ) ). Control stick  100  can move along the y-axis to provide vessel control signal  1020 , which branches into signals  1021  and  1022 , respectively being inputs to function modules  1706  and  1707 . Function modules  1706  and  1707  calculate output signals  1016  and  1017 , which are respectively used to control the port engine RPM actuator and the port reversing bucket position actuator of the system illustrated in  FIGS. 13A-13I -D. The port engine RPM varies between approximately idle speed in the vicinity of zero y-axis deflection to higher engine RPMs when the control stick  100  is moved along the y-axis degree of freedom ( FIG. 16( a ) ). The port reversing bucket  154 P is nominally at a neutral thrust position when the control stick  100  y-axis is in its zero position, and moves up or down with respective forward and backward movement of the control stick  100  ( FIG. 16( b ) ). 
       FIGS. 17A-17B  illustrate the algorithms for generating control signals to control the starboard engine RPM actuator ( FIG. 17( a ) ) and the starboard reversing bucket position actuator ( FIG. 17( b ) ). Control stick  100  provides vessel control signal  1020  for movement along the y-axis, which branches into signals  1023  and  1024 , respectively being inputs to function modules  1708  and  1709 . Function modules  1708  and  1709  calculate output signals  1018  and  1019 , which are respectively used to control the starboard engine RPM actuator and the starboard reversing bucket position actuator of the system illustrated in  FIGS. 13A-13I -D. The starboard engine RPM varies between approximately idle speed in the vicinity of zero y-axis deflection to higher engine RPMs when the control stick  100  is moved along the y-axis degree of freedom ( FIG. 17( a ) ). The starboard reversing bucket  154 S is nominally at a neutral thrust position when the control stick  100  y-axis is in its zero position, and moves up or down with respective forward and backward movement of the control stick  100  ( FIG. 17( b ) ). 
       FIGS. 18A-18B  illustrate the algorithms for generating control signals to control the port and starboard steering nozzle position actuators ( FIGS. 18( a ) and ( b ) , respectively). Helm control  120  provides vessel control signal  1030 , which branches into signals  1031  and  1032 , respectively being inputs to function modules  1710  and  1711 . Function modules  1710  and  1711  calculate linear output signals  1020  and  1021 , which are respectively used to control the port and starboard steering nozzle position actuators of the system illustrated in  FIGS. 13A-13I -D. 
     Movement of the helm  120  n the clockwise direction results in vessel movement to starboard. Movement of the helm  120  in the counter-clockwise direction results in vessel movement to port. The functional relationships of  FIGS. 18( a ) and ( b )  are illustrative, and can be modified or substituted by those skilled in the art, depending on the application and desired vessel response. 
       FIG. 19( a )  illustrates the algorithm for generating a control signal used to control the port engine RPM actuator. Port throttle controller  110 P generates a vessel control signal  1040  that is input to function module  1712 . Function module  1712  determines a linear relation between input vessel control signal  1040  and output signal  1022 . Thus, with the throttle in a full reverse position, the port engine actuator is in an idle position and with the throttle in the full forward position the port engine is at maximum RPM. The output signal  1022  is used as an input to provide the port engine RPM actuator control signal  1050 , as illustrated in  FIGS. 13A-13I -D. 
       FIG. 19( b )  illustrates the algorithm for generating a control signal used to control the starboard engine RPM actuator. Starboard throttle controller  110 S generates a vessel control signal  1041  that is input to function module  1713 . Function module  1713  determines a linear relation between input vessel control signal  1041  and output signal  1023 . This relationship is substantially similar to that of the port engine RPM actuator. The output signal  1023  is used as an input to provide the starboard engine RPM actuator control signal  1051 , as illustrated in  FIGS. 13A-13I -D. 
       FIGS. 20A-20D  illustrate a number of exemplary overall actual vessel motions provided by the control system described in  FIGS. 13A-13I -D for a vessel having two propulsors with steering nozzles, two reversing buckets and no bow thruster. 
       FIG. 20( a )  illustrates movement of the vessel to port along a curved path when the control stick  100  is in the forward (+y) and the helm  120  is in the turn-to-port position. If the helm  120  is placed in the straight ahead position the vessel moves forward only. If the helm  120  is turned clockwise the vessel moves to starboard 
       FIG. 20( b )  illustrates movement of the vessel when the control stick  100  is in the neutral center position. If the helm  120  is turned to port, the vessel rotates about a vertical axis to port. If the helm  120  is in the straight ahead position, no net vessel movement is achieved. Helm  120  motion to starboard is analogous to that for motion to port and will not be described for the sake of brevity. 
       FIG. 20( c )  illustrates movement of the vessel when the control stick  100  is in the to-port position (−x). If the helm  120  is in the turn-to-port position then the vessel both rotates to port about a vertical axis and translates to port. If the helm  120  is in the straight ahead position then the vessel merely translates to port without net forward or rotation movement. Again, helm  120  motion to starboard is analogous to that for motion to port and will not be described for the sake of brevity.  FIGS. 20A-20D  also illustrate movement of the vessel when the control stick  100  is moved to the right (+x position). 
       FIG. 20( d )  illustrates movement of the vessel when the control stick  100  is moved back in the (−y) direction. Here the vessel moves backwards and to the right if the helm  120  is in the to-port position, and the vessel moves straight back if the helm  120  is in the straight ahead position. Helm  120  motion to starboard is analogous to that for motion to port and will not be described for the sake of brevity. 
       FIGS. 30 and 31A -D illustrate the signal control modules and resulting vessel movements, respectively, for another embodiment of a control system that can be used to drive a marine vessel having dual waterjets and a bow thruster, with the dual waterjets comprising respective nozzle and reversing buckets. In particular, it is to be appreciated that the system of  FIG. 30  is a variation of the system of  FIG. 13B , where a bow thruster module  2135  is added to the dual waterjet system and the throttle controls are illustrated as removed for the sake of simplicity. 
     It is to be understood that  FIG. 30  has many of the same components as  FIG. 13B , that these components have been numbered with either identical or similar reference numbers (some references numbers have been eliminated), and that the description of each of the components of  FIGS. 32A-B  has not been duplicated here for the sake of brevity. It is also to be appreciated that although there is no throttles  110 P,  110 S illustrated in  FIG. 30  (See  FIG. 8 ), that such throttles can be part of the control system, as well as other controllers used in the art. In addition, it is to be appreciated that any or all of the joystick  100 , helm  120 , and throttles  110 P,  110 S, can be replaced with an interface to a remote control system, such as described above with respect to  FIG. 29 , that receives any or all of control signals such as any or all of net transverse translational thrust commands, net forward or reverse translational thrust commands, and net rotational thrust commands, and which can be combined and translated into either or both of a net translational and/or net rotational thrust commands In the embodiment of  FIG. 30 , there is provided an additional thruster and rpm module  2135 , that is substantially the same a the bow thruster modules of  FIGS. 8 and 32A -B, except that the functional module has a deadband that corresponds with the deadband of the other functional control modules such as modules  1700 - 1706 , for movement along, for example, the X-axis of the controller. This deadband characteristic is particularly useful for dual waterjet control systems that drive the corresponding reversing buckets to discrete positions, as has been described herein for example with respect to  FIG. 30  and also as described elsewhere herein, as the deadband allows the buckets to be moved to the discrete positions without developing any thrust from the waterjets or thrusters. 
     It is to be appreciated that a plurality of the algorithms or control modules described in  FIG. 30  are substantially the same as the algorithms or control modules described with respect to  FIG. 13B , with the addition of signals and control module  2135  t for controlling a bow thruster. In particular, substantially the same control signals and logic modules can be used for the dual waterjet control system of  FIGS. 13A-13I -D and the dual waterjet and bow thruster control system of  FIG. 30 . However, the calibration points and parameters should change to compensate for the added thrust and rotational moment that would be provided by the bow thruster. It should be appreciated that one of the reasons for adding a bow thruster to any of the dual waterjet embodiments described herein is that as craft sizes increase, length to weight ratios typically increase and power to weight ratios typically decrease, reducing the vessels ability to develop sufficient side thrust without a bow thruster. 
       FIGS. 31A-D  illustrates a number of exemplary overall actual vessel motions provided by the control system described in  FIG. 30  for a vessel having two propulsors with steering nozzles and two corresponding reversing buckets and a bow thruster, which under direction of the vessel control system produce the illustrated vessel movements. It is to be appreciated that the vessel movements illustrated in  FIGS. 31A-D  and for any of the embodiments described herein, are illustrated for corresponding movements of a control stick and helm, however the controllers can be any controller used in the art and can be signals received from a remote controller at a control interface, as has been described herein. 
       FIG. 31A  illustrates movement of the vessel to port along a curved path when the control stick  100  is in the forward (+y) and the helm  120  is in the turn-to-port position. If the helm  120  is placed in the straight ahead position the vessel moves forward only. If the helm  120  is turned clockwise the vessel moves to starboard 
       FIG. 31B  illustrates movement of the vessel when the control stick  100  is in the neutral center position. If the helm  120  is turned to port, the vessel rotates about a vertical axis to port. If the helm  120  is in the straight ahead position, no net vessel movement is achieved. Helm  120  motion to starboard is analogous to that for motion to port and will not be described for the sake of brevity. 
       FIG. 31C  illustrates movement of the vessel when the control stick  100  is in the to-port position (−x). If the helm  120  is in the turn-to-port position then the vessel both rotates to port about a vertical axis and translates to port. If the helm  120  is in the straight ahead position then the vessel merely translates to port without net forward or rotation movement. Again, helm  120  motion to starboard is analogous to that for motion to port and will not be described for the sake of brevity.  FIGS. 20A-20D  also illustrate movement of the vessel when the control stick  100  is moved to the right (+x position), which is analogous to the vessel movement to port, and therefore the description of each vessel movement is not repeated. 
       FIG. 31D  illustrates movement of the vessel when the control stick  100  is moved back in the (−y) direction. Here the vessel moves backwards and to the right if the helm  120  is in the to-port position, and the vessel moves straight back if the helm  120  is in the straight ahead position, and to the left if the helm is in the to starboard position. 
     As can be seen herein, it is the case for both the single and dual propulsor vessel control systems, both with and without bow thrusters as described herein, we see that vessel motion is in accordance with the movement of the vessel control apparatus. Thus, one advantage of the control systems of the invention is that it provides a more intuitive approach to vessel control that can be useful for complex maneuvers such as docking. It is, of course, to be appreciated that the dynamics of vessel movement can vary widely depending on the equipment used and design of the vessel. For example, we have seen how a single-propulsor vessel and a dual-propulsor vessel use different actuator control signals to achieve a similar vessel movement. One aspect of the present invention is that it permits, in some embodiments, for designing and implementing vessel control systems for a large variety of marine vessels. In some embodiments, adapting the control system for another vessel can be done simply by re-programming the algorithms implemented by the above-described function modules and/or re-calibration of the key points on the above-described curves, that determine the functional relationship between a vessel control signal and an actuator control signal. 
     One aspect of marine vessel operation and control that may cause differences in vessel response is the design and use of the reversing buckets. Two types of reversing buckets are in use with many waterjet-propelled vessels: an “integral” design, which rotates laterally with a steering nozzle to which it is coupled, and a “laterally-fixed” design, which does not rotate laterally with the steering nozzle, and remain fixed as the steering nozzle rotates. Both integral and laterally-fixed designs can be dropped or raised to achieve the reversing action necessary to develop forward, neutral or backing thrust, but their effect on vessel turning and lateral thrusts is different. 
     The control system of the present invention can be used for both types of reversing buckets, as well as others, and can be especially useful for controlling vessels that have the laterally-fixed type of reversing buckets, which have traditionally been more challenging to control in an intuitive manner, as will be explained below. The following discussion will illustrate the two types of reversing buckets mentioned above, and show how their response differs. The following discussion also illustrates how to implement the present control system and method with the different types of reversing buckets. 
       FIGS. 21A-21C  illustrate an integral-type reversing bucket  5  that can be raised and lowered as described previously using reversing bucket actuator  7 . The reversing bucket  5  and actuator  7  are coupled to, and laterally rotate with steering nozzle  6 . The steering nozzle  6  and reversing bucket  5  assembly rotates laterally by movement of steering nozzle actuators  8 , pivoting on trunion  9 . 
     Several exemplary modes of operation of the combined reversing bucket and steering nozzle are illustrated in  FIGS. 21A-21C . The columns of the figure (A, B and C) illustrate the steering nozzle  6  being turned along several angles (0°, 30°, 15°) of lateral rotation. The rows (Q, R and S) illustrate several positions (full reverse, neutral and full ahead) of the reversing bucket  5 . In the figure, the forward direction is to be understood to be toward the top of the figure and the aft direction is to the bottom, accordingly, the port direction is to the left and the starboard direction is to the right of the figure. 
       FIGS. 21A-21C  (col. A, row Q) illustrate the steering nozzle  6  in a 0° position (straight ahead) and the reversing bucket  5  in the full-reverse (lowered) position. The resulting combined thrust is then in the backing direction with no net lateral component. The arrows show the resulting direction of flow of water, which is generally opposite to the direction of the resulting thrust on the vessel. 
       FIGS. 21A-21C  (col. A, row R) and (col. A, row S) also illustrate the steering nozzle  6  in the straight ahead position, but the reversing bucket  5  is in the neutral position (col. A, row R) and in its raised position (col. A, row S). Accordingly, no net thrust is developed on the vessel in (col. A, row R) and full ahead thrust is developed on the vessel in (col. A, row S). 
       FIGS. 21A-21C  (col. B, row Q-col. B, row S) illustrate the steering nozzle  6  turned 30° with respect to the vessel&#39;s centerline axis. By progressively raising the reversing bucket  5  from the backing position (col. B, row Q) to the neutral position (col. B, row R), or the ahead position (col. B, row S) thrust is developed along an axis defined by the direction of the steering nozzle  5 . That is, in an integral reversing bucket design, the net thrust developed by the combined reversing bucket and steering nozzle is along a direction in-line with the steering nozzle axis. 
       FIGS. 21A-21C  (col. C, row Q-col. C, row S) illustrate a similar maneuver as that of  FIGS. 21A-21C  (col. B, row Q-col. B, row S), except that the angle of steering is 15° with respect to the vessel&#39;s centerline rather than 30°. 
       FIGS. 22A-22B  illustrate the relation between the water flow direction and the resulting thrust for a configuration having an integral-type reversing bucket  5  coupled to a steering nozzle  6  as in  FIGS. 21A-21C .  FIG. 22( a )  illustrates a case with a 30° steering angle and the reversing bucket  5  in the full ahead (raised) position, as shown before in  FIGS. 21A-21C  (col. B, row S). The waterjet flow direction is in the same direction as the steering nozzle  5 , with a resulting net thrust being forward and to starboard at an angle of substantially 30°. 
       FIG. 22( b )  illustrates the steering nozzle  6  at a 30° steering angle and the reversing bucket  5  being in the full reverse (lowered) position as illustrated in  FIGS. 21A-21C  (col. B, row Q). The resulting flow is in a direction along the axis of the steering nozzle  6 , but reversed by 180° from it. The resulting net thrust is then to the rear and port side of the vessel. Note that vessel design and placement of the nozzle and bucket assembly can impact the actual direction of translation and rotation of the vessel resulting from application of said thrust at a particular location on the vessel. 
       FIG. 23  illustrates the dynamic relationship between the steering nozzle  6  angle and the direction of the resulting thrust in a vessel using an integral reversing bucket  5 . The horizontal axis  5105  represents an exemplary range of rotation of the steering nozzle  6  about the nominal 0° position (straight ahead). The vertical axis  5115  represents the angle of the thrust developed. Two curves are given to show the direction of the thrust for an integral reversing bucket  5  placed in the full ahead position (solid)  5110  and in the full reverse position (dashed)  5100 . It can be seen that in either case, the direction of the thrust developed is substantially in-line with that of the applied steering nozzle direction. That is, the results for the full ahead position  5110  and the results for the full reverse position  5100  are in similar quadrants of the figure. 
       FIGS. 24A-24C  illustrate a laterally-fixed reversing bucket  5 A that can be moved as described previously using a reversing bucket actuator (not shown in this figure). The reversing bucket  5 A and its actuator are not coupled to the steering nozzle  6 A, but are coupled to a waterjet housing or other support which is fixed to the vessel and do not rotate laterally with the steering nozzle  6 A. The steering nozzle  6 A rotates laterally by movement of steering nozzle actuators (not shown in this figure). Reference can be made to  FIG. 5  which illustrates a more detailed side view of a laterally-fixed reversing bucket assembly and steering nozzle. A result of this configuration is that, in addition to reversing the forward-aft portion of the waterjet, the reversing bucket  5 A redirects the water flow with respect to the vessel&#39;s centerline. In most designs, some curvature of the reversing bucket  5 A surface exists and affects the exact direction in which the exiting water flows from the reversing bucket. Also, some designs of laterally-fixed reversing buckets comprise tube-like channels which force the flow to have a certain path along the tube. Others are split into a port and a starboard portion, such that the fraction of the waterjet traveling in the port or the starboard portions depends on the angle of the steering nozzle and affects the thrust accordingly. 
     Several exemplary modes of operation of the laterally-fixed reversing bucket  5 A and steering nozzle  6 A are illustrated in  FIGS. 24A-24C . The columns of the figure (A, B and C) illustrate the steering nozzle  6 A being turned along several angles (0°, 30°, 15°) of lateral rotation. The rows (Q, R and S) illustrate several positions (full reverse, neutral and full ahead) of the reversing bucket  5 A. As in  FIGS. 21A-21C , the forward direction is to the top of the figure and the aft direction is to the bottom, accordingly, the port direction is to the left and the starboard direction is to the right of the figure. 
       FIGS. 24A-24C  (col. A, row Q) illustrate the steering nozzle  6  in a 0° position (straight ahead) and the reversing bucket  5 A in the full-reverse (lowered) position. The resulting combined thrust is then in the backing direction with no net lateral component. Note that there are two lateral components to the waterjet flow in that the port and starboard contributions cancel one another. The arrows show the resulting direction of flow of water, which is generally opposite to the direction of the resulting thrust. 
       FIGS. 24A-24C  (col. A, row R) and (col. A, row S) illustrate the steering nozzle  6 A in the straight ahead position, but the reversing bucket  5 A is in the neutral position in (col. A, row R) and in its raised position in (col. A, row S). No net thrust is developed with the reversing bucket  5 A as illustrated in (col. A, row R) and full ahead thrust is developed with the reversing bucket  5 A as illustrated in (col. A, row S). 
       FIGS. 24A-24C  (col. B, row Q-col. B, row S) illustrate the steering nozzle  6 A turned 30° with respect to the vessel&#39;s centerline axis. By progressively raising the reversing bucket  5 A, from backing position (col. B, row Q), to neutral position (col. B, row R), or ahead position (col. B, row S) thrust is developed along an axis defined by the direction of the steering nozzle  6 A. It can be seen, e.g. by comparing the thrust generated in  FIGS. 21A-21C  (col. B, row R) and  FIGS. 24A-24C  (col. B, row R), that the reversed component of the flow in the laterally-fixed reversing bucket  5 A is not along the same axis as the steering nozzle  6 A, while the integral reversing bucket  5  gave an in-line (but opposing) reversed flow component direction with respect to steering nozzle  6 . 
       FIGS. 24A-24C  (col. C, row Q-col. C, row S) illustrate a similar maneuver as that of  FIGS. 24A-24C  (col. B, row Q-col. B, row S), except that the angle of steering is 15° with respect to the vessel&#39;s centerline rather than 30°. 
       FIGS. 25A-25B  illustrate the relation between the water flow direction and the resulting thrust for a configuration having a laterally-fixed type reversing bucket  5 A and a steering nozzle  6 A as illustrated in  FIGS. 24A-24C .  FIG. 25( a )  illustrates a case with a 30° steering angle of the steering nozzle  6 A and the reversing bucket  5 A in the full ahead (raised) position, as shown before in  FIGS. 24A-24C  (col. B, row S). The flow direction is in the same direction as that of the steering nozzle  5 A, with a resulting net thrust being forward and to port. 
       FIG. 25( b )  illustrates the steering nozzle  6 A at a 30° steering angle to port and the reversing bucket  5 A being in the full reverse (lowered) position. For this configuration, the resulting water flow is in a different direction than that of the steering nozzle  6 A, and not along its axis. The resulting net thrust imparted to the vessel is to the rear and starboard side of the vessel. The reverse thrust can be at an angle greater than the 30° nozzle angle  6 A because the flow channel within the reversing bucket  5 A plays a role in steering the vessel. It is to be appreciated that the vessel design and placement of the nozzle and bucket assembly can impact the actual direction of translation and rotation of the vessel resulting from application of said thrust at a particular location on the vessel. 
     One thing that is apparent from comparing the integral and the laterally-fixed types of reversing buckets is that the lateral component of thrust due to the reversed component of the waterjet in the integral type reversing bucket is in a direction substantially reflected about the vessel&#39;s major axis (centerline) compared to the same thrust component developed by using a laterally-fixed reversing bucket. In other words, the resultant thrust for the integral reversing bucket  5  will be to the port side of the vessel, whereas the resultant thrust with the laterally-fixed reversing bucket  5 A will be to the starboard side of the vessel. 
       FIG. 26  illustrates the dynamic relationship between the steering nozzle  6 A angle and the direction of the resulting thrust in a vessel using a laterally-fixed reversing bucket  5 A. The horizontal axis  5105  represents an exemplary range of rotation of the steering nozzle  6 A about the nominal 0° position (straight ahead). The vertical axis  5115  represents the angle of the thrust developed. Two curves are given to show the direction of the thrust for a laterally-fixed reversing bucket  5 A placed in the full ahead position (solid)  5110 A and in the full reverse position (dashed)  5100 A. It can be seen that in the full reverse case, the direction of the thrust developed is substantially out-of-line with that of the applied steering nozzle direction. That is, the results for the full ahead position  5110 A and the results for the full reverse position  5100 A are in different quadrants of the figure. 
     According to some aspects of the present invention, problems related to the use of laterally-fixed reversing buckets in some embodiments can be overcome. The primary problem with respect to controlling waterjets with laterally-fixed reversing buckets is predicting the overall effect of variable amounts of reverse thrust. This is a significant problem, as the reversing component is not only deflected substantially out of line with steering nozzle angle but at varying degrees with respect to nozzle position. Through the use of specially designed algorithms or control modules and simplified calibration methods, the present invention can in some cases anticipate and correct for such discrepancies and in other cases avoid the influences of these discrepancies all together. The result is a smooth and intuitive operation of the vessel. This of course does not limit the scope of the present invention, and it is useful for many types of reversing buckets. 
     In some embodiments, the marine vessel may have coupled steering nozzles or propulsor apparatus. For example, it is possible to use two steering nozzles that are mechanically-coupled to one another and rotate in unison by installing a cross-bar that links the two steering nozzles and causes them to rotate together. A single actuator or set of actuators may be used to rotate both steering nozzles in this embodiment. Alternatively, the steering nozzles may be linked electrically by controlling both nozzles with the same actuator control signal. It is possible to split an actuator control signal so that separate actuators controlling each steering nozzle are made to develop the same or similar movements. 
       FIG. 27  illustrates an alternate embodiment of a vessel control apparatus  100 A to be used with the various embodiments of marine vessel control system of this disclosure, and exemplary resulting vessel maneuvers. In particular, it is to be appreciated that the vessel control apparatus can be a three-axis (degree of freedom) control or joystick  100 A as illustrated in  FIG. 27 , instead of a two-axis control or joystick and a helm, as has been described by way of example herein.  FIG. 27  illustrates some exemplary resulting maneuvers provided by the herein described marine vessel control system for exemplary motion of the three-axis control stick for a single waterjet vessel, which corresponds to but is a subset of the resulting maneuvers illustrated in  FIGS. 12A-12D .  FIG. 27  also illustrates some exemplary resulting maneuvers provided by the herein described marine vessel control system for exemplary motion of the three-axis control stick for a twin waterjet vessel, which corresponds to but is a subset of the resulting maneuvers illustrated in  FIGS. 20A-20D . 
       FIG. 28  illustrates an alternative embodiment of a marine vessel control system (cabling) diagram for a dual waterjet propulsion system, with a remote control interface  130 . It is to be appreciated that the marine vessel control system need not comprise a vessel control apparatus or a plurality of vessel control apparatus as has been described herein by way of example. Alternatively, the control system can comprise an interface (control box)  130  that receives vessel control signals from a remote control system  131 . For example, the remote control system may provide digital words, e.g. in an ASCII format or any other suitable format to command the control system, or the remote control system may provide analog signal that, for example, mimic the analog signals provided by joystick and/or helm control apparatus as described herein. 
     As will be discussed further with respect to  FIG. 29 , the control box  130  and the control system can receive these signals and provide resulting actuator control signals to marine vessel having for example two waterjets comprising two nozzles  158 P and  158 S, and two reversing buckets  152 P and  152 S. It is to be appreciated that the operation of this system, other than the interface to and translation of signals from the remote control system, is substantially the same as that of  FIG. 7  discussed above, and like parts have been illustrated with like reference numbers and a description of such parts is omitted here for the sake of brevity. Specifically, the control system can comprise a set of functional modules, for example, stored within control processor unit  130 , that receive and translate control signals such as any or all of net transverse translational thrust commands, net forward or reverse translational thrust commands, and net rotational thrust commands, which can be translated into any/or all of net translational and net rotational thrust commands, and from these commands generate the output actuator control signals provided by the control processor unit  130 . 
     Referring now to  FIG. 29 , there is illustrated one exemplary signal diagram for the marine vessel control system comprising a dual waterjet vessel and a remote control interface, as illustrated in  FIG. 28 . In particular  FIG. 29  illustrates a signal diagram of another embodiment of a marine vessel control system for a dual waterjet vessel, which is an variation of the embodiment illustrated in  FIG. 13B , wherein any and/or all of the vessel control apparatus, such the joystick  100 , helm  120 , and port and/or starboard throttles  110 P,  110 S have been replaced with the remote control system interface  130  that receives control signals from a remote control system  131 . It is to be appreciated that the operation of this vessel control system  130  and resulting signal diagram, other than the interface to and translation of signals from the remote control system, is substantially the same as that of  FIG. 13B  discussed above, and therefore like parts have been illustrated with like reference numbers and a bulk of the description of such parts is omitted here for the sake of brevity. 
     Summarizing, the remote control interface also referred to herein as controller or processor  130  receives and translates control signals such as any or all of net transverse translational thrust commands on line  2132 , net forward or reverse translational thrust commands on line  2133 , and net rotational thrust commands on line  2134 , which can be combined and translated into either or both of a net translational and/or net rotational thrust commands. It is to be appreciated that the net translational thrust command on line  2132  corresponds, in other embodiments having for example a first vessel controller such as the joystick controller  100  (see for example  FIG. 13B ) to movement of a first vessel controller apparatus off of center along at least one degree of freedom such as the X-axis. The reversing bucket position (port and starboard reversing buckets) is configured by modules  1700 ,  1703  in response to the received net transverse translational thrust commands on line  2132 , to one of two discrete positions, fully up and fully down. In addition, the engine rpm for the port and starboard engines are varied, by port engine rpm module  1701  and starboard engine rpm module  1704 , to vary proportionally with respect to the net transverse translational thrust commands on line  2132 . 
     It is to be appreciated that the controller as programmed as illustrated in  FIG. 29  provides a set of actuator control signals  1052 ,  1053  so that the first reversing bucket and the second reversing bucket are positioned so that substantially no net rotational force is induced to the marine vessel for received net translational thrust commands. In particular, the processor is programmed to provide the actuator control signals  1052 ,  1053  so that the first reversing bucket is positioned in one of a first and a second discrete position and so that the second reversing bucket is positioned in one of the first and the second discrete positions. In some embodiments, the first discrete position is a substantially full up position and the second discrete position is a substantially full down position. In particular, as illustrated in  FIG. 29 , the first (port) reversing bucket is configured to be in the first discrete position which is a substantially full up position and the second reversing bucket (starboard) is positioned to be in the second discrete position which is a substantially full down position, for net translation thrust commands with a starboard component, and vice versa for net translational thrust commands with a port component. In addition, as has been discussed above with respect to  FIGS. 14B and 15B , the controller or processor is programmed to provide another set of actuator control signals  1050 ,  1051  so that an engine rpm of the first and second steering nozzles varies proportionally to the net translational thrust command In addition, for some embodiments as has been discussed above with respect to  FIGS. 14E and 15E , the processor is programmed to provide the actuator control signals  1050 ,  1051  so that the engine rpm of one of the port and starboard steering nozzles has a step up in engine rpm from the rpm value that varies proportionally to the net translational thrust command, when the corresponding one of the first and second reversing buckets is in a substantially full down position and vice versa. 
     As has been discussed above with reference to  FIGS. 13E-F , this embodiment has an advantage in that the for-aft thrust component (the engine RPM&#39;s) can be modulated (varied for example from full thrust as illustrated in  FIG. 13E  to half thrust as illustrated in  FIG. 13F ) with the reversing bucket at a fixed position, such as full up position, and the nozzle(s) at an angle Θ (presumably required to hold a steady heading of the vessel due to external influences such as water current and/or wind) without affecting the net thrust angle Θ of the waterjet. An advantage according to this embodiment, is that by keeping the reversing buckets stationary while modulating engine RPM only (as illustrated in  FIGS. 13E &amp; 13F ), the control system and hence the operator are able to vary the net thrust magnitude applied to the vessel without applying any unwanted rotational force, thereby resulting in movement of the vessel as illustrated in, for example,  FIG. 13H , and  FIGS. 20A-20D  and  FIG. 27 , as well as  FIGS. 31A-D  to be described herein. 
     According to another embodiment of the invention, there is a need for a system that enables a craft operator to implement bucket assisted turns. In particular, although vessels that are propelled by waterjets are known to be highly maneuverable due to the ability to vector thrust from side to side (typically at angles up to + or −30°) via the steering nozzles, it is some times desirable to implement extremely tight turns at high and low speeds beyond what is achievable by using only nozzles to vector the thrust, particularly when operating in tight quarters. Experienced waterjet craft operators have been known to manually use the reversing buckets to create additional turning force when an extremely tight turn is required. This maneuver is sometimes referred to as a “bucket assisted turn” or a “bucket turn”. 
     According to aspects of the invention, any of the herein described control systems can be modified to implement the following embodiments of a bucket assisted turn. One embodiment of a bucket assisted turn intuitive control device and system includes any of the herein described control devices modified with a proportional pushbutton or an additional control axis device (for example a pushbutton or mini thumb joystick), either integrated into the control device such as a joystick or steering tiller or added as an additional stand alone control device. For example,  FIG. 36A  illustrates a variable output pushbutton device  3601  that provides an output signal that is proportional to the force or the magnitude of displacement of the button.  FIG. 36B  illustrates a joystick  3600  with the variable output pushbutton  3601  of  FIG. 35A  installed such that it can be actuated for example by a thumb of a user of the joystick to initiate a bucket assisted turn by pushing in the pushbutton while making a turn. In particular, according to the principles of the invention as will be described herein, the control system is configured so that actuating the pushbutton when turning the steering wheel or tiller (steering joystick) will proportionally lower the reversing bucket into the water jet stream of the steering nozzle on the side of the vessel to which the steering nozzles are directed to turn the vessel, and to raise the bucket (if not already up) on the opposite side of the vessel (the opposite side to which the steering nozzles are directed to turn the vessel), thereby allowing the operator to execute a bucket assisted turn on demand. According to aspects of this embodiment, the push button and system can be configured such that the further in the button is pushed, the more the corresponding bucket is actuated into the waterjet stream. It is to be appreciated that according to aspects of this embodiment, the feature of raising the opposite reversing bucket (opposite to the side to which the steering nozzles are directed to turn the vessel) is advantageous, but not required. In particular according to aspects of this embodiment, the bucket assisted turn is provided by creating a differential with the reversing buckets between the steering nozzles. This can be accomplished, for example, by any of positioning the bucket into the waterjet stream of the steering nozzle on the side vessel to which the steering nozzles are directed to turn the vessel, or positioning the reversing bucket out of the water jet stream of the opposite steering nozzle, both positioning the bucket into the waterjet stream of the steering nozzle on the side vessel to which the steering nozzles are directed to turn the vessel and positioning the reversing bucket out of the water jet stream of the opposite steering nozzle. 
     Another embodiment of the control system for providing a bucket assisted turn comprises a processor configured to automatically provide a varying magnitude bucket assist signal to implement such a maneuver based on the user simply triggering the maneuver, for example, by simply pushing a push button (for example on the joystick) or toggling a switch. For example, such an embodiment can be configured such that when the button is pushed or the switch is toggled, the processor is configured to provide a varying magnitude bucket assist signal to further position the reversing bucket into the corresponding waterjet stream, in response to, for example, the magnitude of the signal from the steering control device (joystick or helm) with which the vessel is commanded to turn to one side of the vessel. Thus, according to this embodiment, the user need not actuate a push button or variable actuation device with varying magnitude or force, as the processor is configured to automatically generate the reversing bucket assist signal based on the other parameters of the commanded turn. 
     The following Figures are provided to help illustrate the concepts of this embodiment of the invention.  FIG. 33A  illustrates marine vessel motion  3302  and the net force  3304  induced with dual waterjets and with the corresponding reversing buckets  3306 ,  3308  in a neutral thrust position. In particular,  FIG. 33A  illustrates how conventionally turning the nozzles while both reversing buckets are at their neutral thrust position will apply a transverse turning thrust vector  3304  to the craft at approximately the same longitudinal position as the reversing buckets. In contrast,  FIG. 33B  illustrates the concept, according to this embodiment of the invention, of how moving the buckets  3306 ,  3308  differentially, for example with bucket  3306  down and bucket  3308  up, in addition to turning the nozzles creates a net turning vector  3310  further aft of the vessel, thereby increasing the turning moment  3312  on the vessel for the same waterjet thrust magnitude and steering nozzle positions. 
     Similarly,  FIG. 34A  illustrates marine vessel motion  3402  and the resultant thrust angle  3404  with dual waterjets in the maximum nozzle rotation position and with the corresponding reversing buckets  3306 ,  3308  in the full up position. In particular,  FIG. 34A  illustrates the resultant thrust angle  3404  while executing a conventional turn with both reversing buckets  3306 ,  3308  full up and actuating only the steering nozzles to develop the turning forces. In contrast,  FIG. 34B  illustrates marine vessel motion  3410  and the resultant thrust angle  3412  according to this embodiment of the invention, with the dual waterjets in the maximum nozzle rotation position and also with the corresponding reversing bucket  3306  to the side of vessel rotation in the waterjet stream and with the other reversing bucket  3308  in the full up position. In particular,  FIG. 34B  illustrates how lowering the reversing bucket on the side of the turn (for example, lowering the port reversing bucket  3306  into the waterjet stream of the port steering nozzle when turning to port) will increase the thrust angle  3412  of the vessel beyond what can be achieved with steering nozzles only. 
       FIG. 35A  illustrates a typical vessel motion for the turn commanded by a vessel control system with conventional steering nozzles as described with respect to  FIG. 34A , and  FIG. 35B  illustrates the vessel motion for a turn commanded by the vessel control system with a bucket assisted turn, according to the embodiment of the invention as discussed with respect to  FIG. 34B . In particular Fig,  35 A illustrates the craft trajectory while moving forward and executing a conventional turn using conventional steering nozzles only and commanded according to  FIG. 34A . In contrast,  FIG. 35B  shows a tighter turning trajectory that is achieved according to this embodiment of the invention by actuating the reversing bucket into the waterjet stream of the steering nozzle to the side of the vessel to which the vessel is commanded to turn, and by actuating the steering nozzles as described above with respect to  FIG. 34B . 
       FIGS. 37A-37E  illustrates one embodiment of a dual waterjet control system  3700  and process that illustrates a device and process for initiating a bucket assisted turn with the joystick of  FIGS. 36A-36B . In particular,  FIG. 38  illustrates a detailed view of the port and starboard Bucket Turn Modules  3801 ,  3802  of the dual waterjet control system  3700  and process illustrated in  FIGS. 37A-37E .  FIG. 38  illustrates that each of the port  3801  and starboard  3802  Bucket Turn Signal Modules receives two input signals. The first input signal  3804  from the helm  3702  is processed to determine the direction of turn (selects the left turn or right turn control curve). In addition, the magnitude of the second input signal  3806  from the push button (or from another control process) determines the position that the reversing bucket is placed into the waterjet stream of the steering nozzle, or in other words the magnitude of the bucket assist. For example, if the operator of the craft turns the wheel (or tiller) to port and presses the proportional button  3601  half way down, the lower (left turn) curve  3808  of the Port Bucket Adjustment Module  3801  will output a port bucket correction signal  3810  that corresponds to half of the maximum allowable deflection downward. Accordingly, the upper (left turn) curve  3812  of the Starboard Bucket Adjustment Module  3802  will output a starboard bucket correction signal  3814  that corresponds to half of the maximum allowable deflection upwards. Similarly, curves  3816  and  3818  correspond to a commanded turn of the vessel to starboard. 
     According to other aspects of the invention, there is a need for a system that enables a craft operator to slow down or stop marine vessels propelled by waterjets, for example, to slow down or stop such waterjet propelled vessels without the upward transom or downward bow forces that occur on the vessel when using reversing buckets to slow down or stop the marine vessel, as occurs in the related art. Referring to  FIG. 39 , there is illustrated an undesirable side effect of stopping a craft using the reversing buckets  3306 ,  3308  (lowering the reversing bucket into the waterjet stream), which is the substantial upward force (illustrated by force vector  402 ) that can be developed at the transom of the marine vessel as a result of deflecting the waterjet flow forward and down (illustrated by waterjet vectors  404 ,  406 ). This upward force  402  on the transom can cause an undesirable and sometimes dangerous condition by forcing the bow of the vessel down while slowing or stopping the vessel, as is illustrated in  FIG. 39 . Referring now to  FIG. 40 , according to an aspect of various embodiments of the invention disclosed herein, this condition can be mitigated with the waterjet systems of the invention (such as systems that use a laterally fixed reversing bucket as described above) by positioning the steering nozzles  4002 ,  4004  outward while also using the revering buckets  3306 ,  3308  for stopping (lowering the reversing bucket into the waterjet stream), thereby deflecting the waterjet flow forward and to the sides (as illustrated by waterjet vectors  408  and  410  in  FIG. 40 ), and not forward and down as illustrated in  FIG. 39 . According to this aspect of the invention, one advantage is that by deflecting the waterjet flow to the sides and forward, the resulting net force will be a slowing or stopping force (as illustrated by force vector  412  in  FIG. 40 ) with substantially less or no upward force (as illustrated by force vector  414  in  FIG. 40 ) on the transom of the marine vessel. It should be appreciated that any of the herein described control systems can be modified according to this aspect of the invention to implement a slowing down or stopping of a marine vessel. 
     According to other aspects of the invention, there are circumstances and applications where it is useful to develop up and down trimming forces on a marine vessel at slow vessel speeds, thereby improving upon the controllability of the vessel at low vessel speeds as compared to that of the related art. Referring now to  FIG. 41 , there is illustrated an undesirable characteristic of many planning hulls, which is the poor controllability of the marine vessel provided by conventional waterjet systems at slow speeds due to the non-optimal trim characteristics of such systems at hump (transition point from displacement mode to planning mode) and sub-hump (displacement mode, not planning mode) speeds (for example a typical 11 meter planning craft traveling at 15 knots with engines turning at 2200 RPM may have a running trim (bow up) of 7 degrees) due to the hull geometry and weight distribution of the craft combined with the ineffectiveness of trim-tabs and interceptors at such slow speeds. In other words, the trim-tabs and interceptors are not effective at such slow speeds to get the vessel over the hump into planning mode, and the vessel can not get out of displacement mode.  FIG. 41  illustrates exemplary vessel characteristics of such systems at such speeds. In most cases a high trim angle such as 7 degrees has a disadvantage in that it will significantly reduce the crafts directional stability. 
     In contrast, referring now to  FIG. 42 , it is illustrated that according to this embodiment of a control system and method of the invention, this undesirable characteristic can be mitigated by positioning the reversing bucket(s)  4200  at least partially into the waterjet stream so as to develop an upward force component at the transom (illustrated by net force vector  414 ) while also increasing the RPMs of the waterjet (by way of example to 2200 RPM) so as to maintain a same net forward thrust or speed of the marine vessel. In addition, according to another aspect of this embodiment, for the combination of the steering nozzles, reversing buckets and engine RPM as illustrated and discussed with respect to  FIG. 42 , the steering nozzles  4002 ,  4004  can additionally be pointed inward as illustrated in  FIG. 43 . In particular,  FIG. 43  illustrates improved net forces  4006  provided to the marine vessel and corresponding waterjet vectors  4008 ,  4010  resulting from pointing inward the waterjets and using an inner portion  4012 ,  4014  of the reversing buckets. An advantage of this embodiment is that pointing the nozzles inward will increase the amount of upward force  4006  provided on the stern of the vessel to get the vessel in planning mode and also will contribute to minimizing an amount of outward spray from the steering nozzles/buckets. Alternatively, it is to be appreciated according to another aspect of the invention, that by pointing the nozzles inward without positioning the reversing buckets into the waterjet stream will also allow the operator to develop upward forces at the transom without deploying the reversing buckets; however, the magnitude of the upward force will be considerably less as compared to when pointing the nozzles inward in combination with some deployment of the reversing buckets. It is to be appreciated that  FIG. 43  shows the reversing buckets in a substantially down position for illustration purposes, and that the reversing buckets can be and will likely be in an intermediate position (between full up and full down) to deflect a portion of the steering nozzle waterjet, and so as to develop a net forward thrust on the vessel. It should be appreciated that any of the herein described control systems can be modified according to this aspect of the invention to implement (either manually or automatically) increased controllability of a marine vessel at low vessel speeds. 
     According to an aspect of various embodiments of the invention described herein, the control system can be configured to lock out accidental deployment of the reversing bucket(s) into the water jet stream of the corresponding steering nozzle(s). For example, it is desirable when operating in heavy sea states (where the operator is subjected to extreme craft motions), to prevent accidental deployment of the reversing buckets, which can create a dangerous condition, as the upward force applied at the transom from positioning the reversing bucket(s) into the steering nozzle(s) water jet stream(s) can force the bow down into the water, causing the craft to stuff. “Stuffing” is a term of art, which correspond to the violent condition where a planning craft bow crashes down into the water, which can cause harm to craft operators as well as passengers. According to aspects of the invention, the risk of stuffing the craft can be minimized by implementing a “lockout” feature where the buckets are locked in the up or near-up position such that the operator can not inadvertently deploy the reversing buckets. For example, referring to  FIG. 36B , a “Bucket Lockout” mode is provided, which can be turned on or off by using a pushbutton such as button  3602  shown in  FIG. 36B . Other embodiments of a control system may use a multi-position switch where one position of the switch will correspond to normal operation (buckets and RPM controlled by the joystick) and a different position of the switch will lockout the buckets (bucket position will not be effected by the joystick). This feature can also be implemented in a single axis control lever system, where each control lever is configured to control the RPM and reversing buckets of the respective waterjet under normal operation, and to only control the RPM when in a Lockout mode. 
     Having described various embodiments of a marine vessel control system and method herein, it is to be appreciated that the concepts presented herein may be extended to systems having any number of control surface actuators and propulsors and is not limited to the embodiments presented herein. Modifications and changes will occur to those skilled in the art and are meant to be encompassed by the scope of the present description and accompanying claims. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the range of equivalents and disclosure herein.