"PROPULSION AND CONTROL SYSTEM FOR A MARINE VESSEL"

FIELD OF THE INVENTION

The present invention relates to a propulsion and control for a marine vessel.

BACKGROUND TO THE INVENTION

A number of different control systems may be used to control the movement of a marine vessel that is propelled by one or more waterjet units. The magnitude and direction of the net thrust vector produced by a waterjet is a function of the throttle setting of the engine driving the waterjet, the position of the reverse deflector and the angle of the steering deflector or nozzle. Traditionally, one or more control levers are used to control the position of the waterjet reverse duct(s) and the throttle setting of the engine(s) driving the waterjet unit(s), while a helm wheel is used to control the position of the steering defiector(s) or nozzle(s) of the waterjet unit(s). Thus the surge, sway and yaw of the vessel may be controlled at both high and low speeds via operation of the control lever(s) and helm wheel together in various combinations.

More recently, joystick control devices have been incorporated into the control systems of waterjet vessels to provide an alternative means of manoeuvring, particularly for low speed operations such as docking and setting off. For example, International PCT Patent Publication No. WO 01/34463 describes a control system which in one embodiment utilises the combination of a dual axis joystick and helm wheel for manoeuvring a boat driven by twin waterjet units, and US Patent No. 6,386,930 describes a control system which utilises a 3-axis joystick.

Bow and stern thrusters may also be installed in vessels to enhance manoeuverability when docking and setting off. The bow and stern thrusters can be controlled by joystick or other control devices as described in US Patent No. 6,538,217. WO98/25194 also discloses a three axis control device for a marine vessel.

It is an object of the present invention to provide an improved system device for manoeuvring a marine vessel or at least alternative.

SUMMARY OF THE INVENTION

In a first aspect, the invention broadly consists of a propulsion and control system for a marine vessel comprising: two or more waterjet units for propelling the vessel; a control device including a manually moveable control element which is movable in two axes and/ or to which force may be applied manually into two axes for controlling two of forward-reverse, port-starboard, and movement of the vessel; and an associated control system which operates the waterjet unit(s) to manoeuvre the vessel in accordance with the movement of the control element.

In a second aspect, the invention broadly consists in a propulsion and control system for a marine vessel comprising: one or more waterjet units for propelling the vessel and one or more lateral thrusters; a control device including a manually moveable control element which is movable in two axes and/or to which force may be applied manually in two axes for controlling two of forward- reverse, port-starboard, and rotational movement of the vessel; and an associated control system which operates the waterjet unit(s) and lateral thruster(s) to manoeuvre the vessel in accordance with the movement of the control element.

In one form the control element of the control device is movable in a first axis which controls forward-reverse thrust of the propulsion unit(s) and in a second axis which controls lateral thrust for the vessel, and the vessel is provided with a separate helm control device such as helm wheel for controlling rotation of the vessel. Alternatively the control device of the invention may comprise an arrangement of one or more sensors responsive to force on the control element in a fore-aft axis to control forward-reverse thrust and movement and in a lateral axis to control port- starboard thrust and movement of the vessel. Alternatively again the control element may be movable in one axis and force sensor-based in another axis.

In another form of the control device of the invention the control element in a fore-aft axis controls forward-reverse thrust and movement of the vessel and is rotatable about it's center point to control rotation of the vessel, and optionally a separate control device may be provided for controlling port-starboard movement of the vessel or thrust from the propulsion unit(s) and/ or lateral thruster(s) of the vessel. Alternatively again the control element may be responsive to force

applied along a lateral axis to control port-starboard movement of the vessel and may be responsive to rotational force around it's center point to control rotational movement of the vessel, or the control element may comprise a movement-based axis and a force sensor-based axis.

Preferably, the control system operates the waterjet units so that displacement of, or force applied to, the control element in an axis causes a corresponding rate of movement for the vessel in the direction of that axis, and rotation of the control element, or rotational force applied to the control element, either clockwise or anticlockwise, causes yaw of the vessel about a vertical axis.

The control element may be biased toward a neutral position with respect to any axis in which the control element is movable. The control system is arranged to operate the waterjet units at zero thrust when the control element is in a neutral position.

The control system may also be arranged such that increasing displacement of, or pressure on, the control element from a neutral position increases thrust for translational movements of the vessel. Similarly, the angle of rotation from the neutral position or amount of rotational force applied to the control device corresponds to the rate of yaw desired.

Preferably, the control system generates signals which actuate the steering deflectors and reverse ducts of the waterjet units and the engine throttles.

Typically the vessel has at least one port waterjet unit and at least one starboard waterjet unit. The control system is preferably arranged to actuate the steering deflectors of the waterjet units in synchronism, while the reverse ducts of the waterjet units may be actuated in synchronism or differentially.

The control element is operable by a user's hand and may be vessel-shaped or have a shape which is representative of a marine vessel. Alternatively, the control element may be shaped like a computer mouse or otherwise to fit in the hand of an operator.

In either of the first or second aspects of the invention described above, the control device may further comprise one or more additional manually operable control inputs for changing the relationship between the control element movement and the thrust response from the waterjet(s). For example, the additional control input may be in the form of a thumbwheel embedded in the control element.

The control device may be switchable between a low speed mode suitable for controlling low speed manoeuvres and a cruise mode suitable for controlling vessel manoeuvres at higher speeds.

In a third aspect in broad terms the invention comprises a propulsion and control system which is operable to manoeuver a marine vessel propelled by one or more waterjet units, comprising: a first manually manipuable control device including a control element which is moveable, and/ or to which force may be applied manually, in one axis and about another axis for controlling forward-reverse and rotational movement of the vessel; a second control means for controlling lateral thrust for the vessel; and an associated control system which operates the waterjet unit(s) or the waterjet unit(s) and one or more lateral thruster(s) to manoeuver the vessel in accordance with the movements of and/ or the directions of forces applied to the two control devices.

The first control element may be vessel-shaped or have a shape which is representative of a marine vessel. Alternatively, the control element may be shaped like a computer mouse or otherwise to fit in the hand of an operator. Alternatively again, the first control element may be a joystick or other stick control device having movement in a fore-aft axis and which is rota table about an axis approximately through the joystick.

The second control means may be a control device such as a joystick or similar stick control device having freedom of movement in a lateral or port-starboard axis. Alternatively a second control device may comprise a rotatable wheel mounted for rotation about a fore-aft axis so that the wheel can be manually rotated in the port-starboard axis by the operator, or means such as port and starboard buttons which are pressed to actuate port thrust from a bow thruster or starboard thrust from a bow thruster, or port or starboard thrust via differential thrust of a multi- waterjet unit drive system for example, as will be further described.

Preferably, the control system generates signals which actuate the steering deflector and reverse duct(s) of the waterjet unit(s), the engine throttle and the motor of the bow thruster.

Both or either of the two control devices may be biased toward a neutral position (as later defined). The control system is arranged to operate the waterjet unit(s) and lateral thruster(s) if provided, at zero thrust when both the control devices are in such neutral positions.

The control system operates the waterjet unit(s) or waterjet unit(s) and any lateral thruster(s) so that displacement of the control element or force applied to the control element of the first control device in a fore-aft axis causes movement of the vessel in the forward or reverse direction, and so that rotational force applied to the first control element, or rotation of the first control element, either clockwise or anticlockwise, causes yaw of the vessel about a vertical axis. The control system also operates the waterjet unit(s), or waterjet unit(s) and bow thruster, so that movement of or force applied manually to the second control device in a port-starboard axis causes port or starboard movement of the vessel.

Preferably, the control system is arranged such that increasing displacement of, or force on, the first control device in the fore-aft axis from or relative to a neutral position increases forward or reverse thrust from the waterjet units. Similarly, the angle of rotation from the neutral position or amount of rotational force or torque applied to the first control element corresponds to the rate of yaw desked. Optionally increasing displacement of, or force on, the second control element in the port-starboard axis from or relative to a neutral position may also proportionally increase lateral thrust from the waterjet unit(s) or bow thrusters or waterjet unit(s) and bow thrusters.

The control system may further comprise one or more additional manually operable control inputs for changing the relationship between movement or force applied to one or both of the control devices and the thrust response from the waterjet(s) and/or bow thrusters. For example, the additional control input may be in the form of a thumbwheel associated with the first control device.

The control system may be switchable between a low speed mode suitable for controlling low speed manoeuvres and a cruise mode suitable for controlling vessel manoeuvres at higher speeds.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

The term 'comprising' as used in this specification and claims means 'consisting at least in part of, that is to say when interpreting statements in this specification and claims which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present.

In this specification and the accompanying claims the term "vessel" is intended to include boats such as smaller pleasure runabouts and other boats, larger launches whether mono-hulls or multi-hulls, and larger ships. More generally, the control device of the invention may be suitable for any planing or displacement type vessels, regardless of their size, speed capabilities, and hull type.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

Various forms of the invention will be described by way of example only and with reference to the drawings, in which:

Figure 1 schematically illustrates one form of control system of a propulsion and control system of the invention;

Figure 2 is a perspective view of a control device of a propulsion and control system of the invention;

Figure 3 shows use of the control device of the invention;

Figure 4 is a cutaway perspective view of the structural components supporting the control element of the control device;

Figure 5 is a perspective view of a second control device used in a control system as will be further described;

Figure 6 is a perspective view of another control device similar to that of Figures 2-3 which is provided with an additional control input in the form of an operable thumbwheel; Figures 7a-7c show graphically, by way of example only, how the thumbwheel of Figure 6 may control gain, sensitivity and engine idle speed respectively;

Figure 8 is a schematic diagram of a propulsion and control system comprising twin waterjet units on a marine vessel;

Figure 9 shows a number of fundamental manoeuvres which are possible with the system of Figure 8;

Figure 10 is a schematic diagram of a propulsion and control system and comprising twin waterjet units and a bow thruster on a marine vessel;

Figure 11 shows a number of fundamental manoeuvres which are possible -with the system of Figure 10; Figure 12 shows a number of fundamental manoeuvres which are possible with the system of Figure 11;

Figure 13 is a schematic diagram of a propulsion control system and single waterjet unit and a bow thruster on a marine vessel; and

Figure 14 shows a number of fundamental manoeuvres which are possible with the system of Figure 13.

DETAILED DESCRIPTION OF EMBODIMENTS

A propulsion and control system of the invention may comprise a preferred form of control device now described for controlling the propulsion system including both the primary waterjet propulsion unit(s) and any lateral thruster(s) primarily during manoeuvring a marine vessel, boat, ship or the like at low speeds, such as docking or setting off. The control device is arranged to operate the vessel's propulsion units to control a range of vessel movements including surge, sway and yaw, or a combination thereof.

Referring to Figure 1 a system incorporating the preferred form control device as first control device 100 also includes a second control device 200. Both control devices generate control signals to an associated electronic control system which in turn controls the propulsion unit(s), and any lateral thrusters if provided, of the vessel.

Figures 2 and 3 show the first control device of the invention in more detail. The control device 100 is provided with a housing 101 which supports a control element 102 having a shape representative of a vessel. The shape of the control element 102 may be varied and does not necessarily have to be vessel-shaped. Any shape which is operable by the hand of an operator would be suitable.

The control element 102 is moveable with one degree of freedom in an X-axis which corresponds to a fore-aft axis of the vessel, and is not rotatable but is responsive to torque applied to the control element by twisting the control element, clockwise or anticlockwise, about a Z-axis. The control element is also biased toward a neutral position with respect to the X-axis and about

- B - the Z-axis. With respect to the Z-axis the neutral position the control system is arranged to operate the waterjet units at zero thrust when the control element is in a neutral position, being a position towards which the control element is biased when not moved by the operator for any axis or axes in which the control element is movable, and when no force is applied to the control element in or about any axis or axes in which the control device is responsive to manual force.

The control system, operates the vessel's propulsion units to manoeuvre the vessel in accordance with manipulation of the control element 102. In particular, the control system operates the vessel's propulsion units so that displacement of the control element along the X-axis causes a corresponding forward or reverse translational movement (surge) of the vessel. Rotational force appEed to the control element by the operator, clockwise or anticlockwise, about its Z-axis causes a corresponding yaw movement of the vessel.

As shown in Figure 4, the control element 102 is mounted to a shaft or pillar 105 which protrudes through a shaped aperture in top cover 103 of the housing 101. An arrangement of strain gauges 150 are mounted to the shaft 105 to generate a Z-axis signal representative of the direction and degree of rotational force or torque applied to the control element 102 about the Z- axis from the center (neutral) position. The shaft or pillar 105 is mounted to a lower plate 107 which is slidably mounted to a base 109 of the housing 101 via longitudinal slides 110 which enable the control element 102 to move along the X-axis. Spring mechanisms and a potentiometer are provided between the fixed base 109 and the lower plate 107. The spring mechanisms bias the control element 102 toward a central position (neutral position) when it is not being operated, while the potentiometer generates an X-axis signal representative of the position of the control element 102 relative to the neutral position.

Figure 5 shows the second control device 200 which in the preferred form shown includes a stick control member 201 having one degree of freedom and which is mounted so that movement of the stick control member 201 is in a port-starboard axis relative to the vessel, or Y- axis. In the preferred form the second control element is biased towards a neutral center position in the Y-axis as shown. The control system also operates the vessel's propulsion units in accordance with manipulation of the second control device. In particular the control system operates the propulsion units so that movement of the stick control member 201to port or starboard along the Y-axis causes a corresponding port or starboard translational movement (sway) of the vessel. This may be caused by operating a bow thruster, alone or in combination with movement of the steering nozzle or nozzles of a single or multi waterjet propulsion system, by

operating a multi waterjet unit in differential thrust mode as will be described further, or operating a multi waterjet propulsion unit in differential thrust mode combined with operating a bow thruster in a vessel comprising a multi waterjet propulsion unit and also one or more bow thrusters.

The second control device 200 or equivalent may be potentiometer based and movable in an arc or alternatively displacably movable along a plane, or alternatively comprise an arrangement of force sensors which are responsive to pressing of a fixed control stick in a port or starboard direction. The second control device may proportionally control the degree of lateral thrust from the propulsion system, with a greater degree of movement of the stick control member 201 to port causing a greater degree of sway of the vessel to port for example and vice versa to starboard, or alternatively the second control device may control port or starboard thrust in simply an on/off mode. For example, movement of the stick control member 201 to port may turn on a bow thruster at a fixed speed to apply fixed thrust to port and vice versa to starboard. In a further alternative configuration the second control element may comprise simply port and starboard buttons or similar which if pressed (and typically while remaining pressed) turn on a bow thruster, or cause multi jet propulsion unit to apply differential thrust for example.

It will be appreciated that there are various other mechanical, electrical and electronic arrangements which may be utilised to sense the position or movement of the first or second control devices 100 and 200, relative to a neutral position to thereby generate the X-axis and Y-axis signals, such as magnetic, inductive, or optical technologies. Similar technologies may be used where the control element 102 of the control device 100 moves rotationally about the Z-axis so that for example the shaft or pillar 105 or equivalent may comprise a rotary potentiometer.

In response to the X-axis, Y-axis, and Z-axis signals from the two control devices 100 and

200, the control system operates the vessel's propulsion unit(s) and any lateral thrusters provided, to cause the vessel to surge, sway and/ or yaw. For example, if the operator wants the vessel to surge forward, the operator simply moves and holds the first control element 102 forward along the X-axis. The further forward it is displaced, the more thrust is produced in that direction by the vessel's propulsion unit(s). Similarly, to cause a translational movement of the vessel in the transverse direction, the second control element 201 is tipped sideways along the Y-axis. If the operator requires to rotate the vessel, the operator applies rotational force to the first control element 102, clockwise or anticlockwise, in the appropriate direction about the Z-axis, and again, the greater the torque applied, the greater the vessel's rate of turn or yaw. A vast range of vessel manoeuvres are possible which combine the basic surge, sway and yaw movements. For example, it

is possible to sway the vessel to port while also surging the vessel ahead and/or yawing the vessel clockwise or anticlockwise.

The control system may, for example, have a microprocessor, microcontroller, programmable logic controller (PLC) or the like, which is programmed to receive and process the X-axis, Y-axis and Z-axis signals generated via the two control elements. The control system processes these signals to determine the desired manoeuvre required by the operator. Once the control system has determined the type of manoeuvre desired, it generates and sends control signals to the vessel's propulsion units to manoeuvre the vessel. The control system can be pre- loaded with data pertaining to the type and number of propulsion units onboard and can be preprogrammed to operate the or each propulsion unit in combination or alone to manoeuvre the vessel in accordance with the operation of the control elements.

At or towards the limit of movement of the control element of the first control device of the invention 100 in any axis in which the control element is movable, the resistance provided by a spring mechanism, against the pressure of which the operator moves the control element 102, may increase, by use of one or more variable rate spring mechanisms for example, or any other suitable mechanical arrangement. During a first and typically greater part of the range of movement of the control element in the axis, the operator moves the control element against a lesser level of spring pressure and then in a second and typically lesser part of the movement towards the maximum extent of movement of the control element in that axis the bias against which the operator must move the control device increases. At the same time the control system is arranged to cause the rate of thrust increase or rate of movement or turn of the vessel to increase more rapidly during the second part of movement of the control element. Alternatively a force sensor may be provided at or towards the limit of movement of the control element in any axis again at either end of the extent of movement, against which the operator presses to increase the rate of thrust or vessel movement or turn increase at the limit of movement of the control element in the axis.

By "manipulation" in this specification in relation to the control element 102 is meant the application of manual pressure to the control element in any axis by pressing or pushing the control element in any forward, reverse, sideways or combined directions, and/ or by twisting the control element as if to rotate the control element and manipulation or manipulate or similar are not to be understood as requiring actual movement of the control element.

Figure 6 shows an alternative form of the first control device of the invention which, along with the control element 102, has an additional manually operable control input in the form of a thumbwheel 300 embedded in the top surface of the control element 102. The thumbwheel 300 may be arranged to control various parameters and settings relating to the way in which the control system operates the vessel's propulsion units during low (or high) speed manoeuvring.

Referring to Figure 7a, the thumbwheel 300 may, for example, be arranged as a gain control for controlling the level of thrust which is demanded in response to manipulation of one or both of the control devices. In particular, the thumbwheel 300 may be operated to control the relationship between the displacement of the first control element 102 from the neutral position, with respect to both movement in the X-axis and/ or rotational force about the Z-axis, and the level of thrust demanded. In this arrangement, the position of the thumbwheel 300 determines the thrust demand at each control element 102 position with respect to the neutral position and provides the user with a means of setting the upper or maximum speeds attainable during a manoeuvre.

Figure 7a illustrates graphically how the thumbwheel 300, functioning as a gain control, may control the relationship between the displacement of the control element 102 from the neutral position and the thrust level. By way of example, the thumbwheel may have five positions 301-305 and therefore five different gain settings, position 301 being the lowest gain setting and position 305 being the highest. As the thumbwheel 300 is rotated from position 301 to 305 the thrust level at any particular control element displacement (apart from at the neutral position) increases, and vice versa as the thumbwheel is rotated from position 305 to 301. Hence the thrust level at each control element position, and therefore the thrust level during any surge, sway, yaw or combination manoeuvre, will depend on the thumbwheel position.

It will be appreciated that the relationships shown in Figure 7a need not necessarily be linear. Furthermore, the thumbwheel need only have two distinct positions, but may have many more, or alternatively may operate in a continuous manner without any distinct positions.

In operation, the gain control thumbwheel generates a gain control signal which represents the position of the thumbwheel. The control system receives and processes the gain control signal and operates the vessel's propulsion units to generate the desired level of thrust during manoeuvring.

In an alternative arrangement, the thumbwheel 300 may control the sensitivity of the control device and in particular the response time of the vessel to perform a desired manoeuvre as shown in Figure 7b. For example, when the thumbwheel is positioned for higher sensitivity 305 (fast response time), the control system will operate the vessel's propulsion units to rapidly perform desired vessel manoeuvres in accordance with movements of the control element. Conversely, if the thumbwheel is positioned for lower sensitivity 301, vessel manoeuvres will be performed more sluggishly. Typically, the response time will depend on the rate of change of thrust and rate of change of steering and therefore these will be controlled in accordance with the thumbwheel sensitivity setting.

Referring to Figure 7b, two possible relationships are shown between the thumbwheel position and the response time. The first relationship 306 is a linear one in which the response time will alter linearly with respect to the thumbwheel position. The second relationship 307 is nonlinear and it will be appreciated that any desired linear or non-linear relationship could be employed by programming or arranging the control system appropriately. As with the gain control thumbwheel arrangement, the sensitivity thumbwheel generates a sensitivity control signal which is received and processed by the control system to control the response time.

In another alternative arrangement, the thumbwheel 300 may control the engine idle speed(s) of the vessel's propulsion unit(s) according to a linear 308 or non-linear 309 relationship as shown in Figure 7c, wherein the engine idle speed(s) are the speed(s) of the engine(s) of the propulsion unit(s) when the control element 102 is in the neutral position demanding zero thrust.

It will be appreciated that the thumbwheel 300 may be arranged to control other parameters and settings, or any combination thereof. For example, the thumbwheel 300 may be arranged to control both the gain and engine idle speed. With such an arrangement, the thumbwheel 300 would control the relationship between the displacement of the control element 102 and the thrust level demanded as described above with reference to Figure 7a, and would also control the engine idle speed as described with reference to Figure 7c. For example, moving the thumbwheel 300 from position 301 to a higher position (302-305) would increase gain and would also increase the engine idle speed of the propulsion units.

There may be multiple thumbwheels controlling different parameters and settings, or a combination thereof. Alternatively, a single multi-purpose thumbwheel may be provided which can be switched to control different parameters and settings, or a combination thereof.

The additional control input or inputs for low speed manoeuvring need not necessarily be in the form of a thumbwheel. They may, for example, be push buttons, slide switches, rocker switches, rotary switches, levers, touch pads, dials, or any other type of manually operable input device. Furthermore, the additional control input or inputs need not necessarily be provided on or in the control element 102 of the control device. They may be located at any other position on the housing 101 of the control device or may be remote from the housing 101 and control element 102 altogether.

The control system of the invention may also be used to manoeuvre vessels at higher speeds, for example when cruising. The first control device may have a mode change input device, such as a button or switch, which enables the user to switch the control device between a low speed mode and a cruise mode. When in cruise mode, the control element 102 may be moved forward and backward in the X-axis to control the fore and aft surge of the vessel and may be twisted about the Z-axis to control the yaw or steering of the vessel to port or starboard. Preferably the control device is arranged so that when in cruise mode the control element is not centre-biased along the X-axis and will remain in the forward (or reverse) thrust position to which it is displaced by the operator to maintain under way thrust. For example, the control element may be arranged as a friction device or the like which maintains its position until it is moved by the operator. Where in an embodiment the X-axis is an axis in which the control device is responsive to force appEed to the control element rather an axis in which the control element moves, in cruise mode forward pressure on the control device to command a particular forward thrust or speed does not need to be maintained to maintain a set speed i.e. the commanded thrust level is maintained when the control device is released ("hands off) until the operator pushes a control element in the reverse direction in the X-axis. Sway thrust at higher speeds when cruising would be disabled for safety reasons by locking out movements of the second control device in the Y-axis mechanically. Alternatively, the second control device may be free to move in the Y-axis, but the Y-axis signal would be disregarded by the control system when the system is in cruise mode.

In the preferred embodiment described above with reference to the drawings the control element 102 of the first control device 100 is movable in the fore-aft axis, and is non-movable but responsive to rotational force about the Z-axis. In alternative embodiments the first control element 102 may be movable also rotationally about the Z-axis. For example, the force sensors 150 may be replaced by a rotary potentiometer which provides a signal to the control system indicative of the rotational position of movably a rotatable control element 102. An arrangement

of any other sensors responsive to movement of the control element in both the Y-axis and about the Z-axis may alternatively provided, to again, generate control signals indicative of the directions of movement of the control device.

The following examples 1-4 describe control system embodiments, all of which utilise a control device of the invention as a first control device for controlling the X and Z axis and translation and rotation of the vessel. They are described by way of example only.

Example 1 - Control System for a Vessel with Multiple Waterjet Units

(Differential Thtust Capable)

Referring to Figure 8, a schematic arrangement of the control system described above installed in a vessel propelled by twin waterjet units 111 is shown. The waterjet units 111 are typically placed port and starboard at the stern of the vessel. Three, four or possibly more units may be controlled together. Each unit is driven by an engine 113 through a driveshaft 114 and has a housing containing a pumping unit 112, steering deflector 115 and reverse duct 116. In this case the reverse ducts are each of a type that feature split passages to improve reverse thrust and affect the steering thrust to port and starboard when the duct is lowered into the jet stream. The steering deflectors pivot about generally vertical axes 117 while the reverse ducts pivot about generally horizontal axes 118 independently of the deflectors. Actuation of the engine throttle, and of the steering deflector and reverse duct of each unit is caused by actuation signals received through control input ports 119, 120, 121 respectively.

For clarity, the control devices 102 and 200 are shown as the only manual control devices for the vessel, although it will be appreciated that in practice it may supplement other steering and thrust control system arrangements which utilise a joystick, a helm control, and throttle lever(s) for higher speed or all speed control.

As mentioned, X-axis, Y-axis, and Z-axis signals 122 are generated in response to manipulation of the control devices 100 and 200 by an operator. The signals 122 are received by a control system 123, and are processed and sent 124 to actuator modules 125 to operate the waterjet units and engine throttles to manoeuvre the vessel. In particular, the actuator modules 125 generate actuation signals 126 which are input through ports 119, 120, 121 to control the engine throttle, and steering deflector and reverse duct of each waterjet unit. While the control devices 100 and 200

are shown as hardwired to the actuator modules 125, alternatively the control devices may, for example, communicate with the vessel's control system and/ or actuator modules via a wireless link.

Figure 9 shows six basic low speed manoeuvres of a vessel which may be enabled by the control system. These include four translations 1,2,5,6 in which the vessel moves ahead, astern, to port or to starboard respectively, while maintaining a constant compass heading. Figure 9 also shows two rotations 3,4 in which the vessel turns to port or starboard about a center point in the vessel respectively. Manoeuvres resulting from the operation of the control devices 102 and 200 in each case are shown. The steering deflectors are operated in synchronism while the reverse ducts are operated in synchronism or differentially as summarised in Table 1 below. Virtually any movement of the vessel may be achieved by a combination of these basic manoeuvres.

Displacing the control element 102 of the first control device ahead or astern synchronises the reverse ducts and throttle demands and the effect is the same as operating a vessel with a single waterjet in manoeuvres 1, 2. While located at its neutral position in the X-axis, rotating the first control element 102 clockwise or anticlockwise in manoeuvres 3,4 causes a partial lowering of the

reverse ducts and full movement of the steering deflectors to rotate the vessel about its center in a corresponding direction. Pushing the second control device 200 transversely causes the vessel to translate sideways in manoeuvres 5,6 via a combination of differential thrust and steering. In particular, the port and starboard waterjets produce differential thrust (Le. one waterjet unit produces ahead thrust with the reverse duct raised while the other produces astern thrust with the reverse duct lowered) which causes the vessel to rotate about the stern. However, the steering deflectors of the waterjet units are also positioned to counteract this rotation, resulting in a sideways translation of the vessel. The control system may automatically apply a preset movement of the steering nozzles ("steering offset") on movement of the control element 102 from the neutral position in the Y-axis. Alternatively the degree of steering offset applied may be varied by the control system to be proportional to the thrust level simultaneously commanded by the operator. Alternatively again an autopilot system associated with the control system may operate in conjunction with the control system to maintain a constant commanded heading (direction of the bow of the vessel) during the sideways translation — that is, when the operator moves the control element 102 to port or starboard in the Y-axis to command a port or starboard sideways translation of the vessel, the position of the steering nozzles may be controlled by the control system but based on heading information provided by an autopilot system, so that the steering nozzles are initially positioned and adjusted as necessary during the translation movement, to maintain a constant heading, or a commanded heading, for the vessel. Alternatively again a rate sensor arranged to generate a turn rate signal indicative of vessel turn rate may be provided and the control system may be configured to monitor for any turn via the turn rate sensor at the bow of the vessel, and to adjust the position or angle of the steering nozzles to compensate so as to maintain a constant heading during a sideways translation; the control system may be configured to receive a vessel actual turn rate signal from the turn rate sensor and a desired turn rate signal and to compare the two and to control the steering nozzles to minimise a difference between the signals, and maintain or initiate a desired turn rate where the control device is manipulated by the operator to cause the vessel to also turn during a sideways translation of the vessel; the turn rate sensor may be a yaw rate sensor for example a rate gyro fixed to the vessel to sense yaw motions of the vessel. Any of these functionalities for providing steering offset via the control system during a sideways translation may be provided to the systems described in the subsequent examples 2-4.

It will be appreciated that the control device may be provided with one or more additional manually operable control inputs in the form of a thumbwheel 200 or other input device as discussed above to control gain, sensitivity, engine idle speed, or any combination thereof and that

the control system may be arranged to operate the waterjet units 111 and/ or engines 113 in accordance with the operation of the additional control input(s).

The first control device may also be operated to manoeuvre the twin waterjet vessel at higher speeds when cruising. As mentioned above, the first control device may have a mode change button or the like for switching between a low speed mode and a cruise mode. Operation of the first control device 100 in the low speed mode in conjunction with the second control device 200 has been described above with reference to Figure 9 and Table 1. When in cruise mode, the control system 123 (Figure 8) disregards the Y-axis signal from the second control device 200, which represents sway demand (transverse translational movements) and therefore does not operate the waterjet units 111 to produce differential thrust. Alternatively the second control device 200 may be disabled. The control device 102 controls the surge of the vessel and the yaw or steering of the vessel. In particular, the control system 123 operates the engine throttles 113 and reverse ducts 116 of the waterjet units 111 in a synchronised manner in accordance with movement of the control device 102 in the X-axis to surge the vessel fore and aft as desired, and operates the steering deflectors 115 in accordance with rotation of the control device 102 about the Z-axis to yaw or steer the vessel to port or starboard as desired. As mentioned, the first control device 102 may, when in cruise mode, be arranged as a friction device or the like so that it maintains its position until it is moved by an operator i.e. it is not center-biased.

Example 2 —

Control Device for a Vessel with Multiple Waterjet Units and Lateral Thrustet (s)

(Differential Thrust Capable)

Figure 10 shows a variant of the schematic arrangement described with reference to Figures

8 & 9 in which the second control device 200 also controls a lateral thruster, such as a bow thruster 136, to supplement the thrust forces provided by the twin waterjet units 111 during various vessel manoeuvres, such as sideways translations and vessel rotations, undertaken at low speeds.

The bow thruster 136 is located at the bow 135 of the vessel and is operable to produce lateral thrust forces to either port or starboard as indicated by thrust vectors 137,138 respectively. The bow thruster 136 has, for example, an impeller driven by a reversible motor. The reversible motor is operated by an actuator module 139 which sends actuation signals 140 to control the speed and direction of the reversible motor and thereby the direction and magnitude of the lateral thrust produced by the bow thruster 136.

In operation, the control devices 100 and 200 control the waterjet units 111 and engines 113 in the same manner as described above in relation to example 1. In addition, the control device 200 also controls the bow thruster 136 for particular vessel manoeuvres. In particular, the control device 200 sends a control signal 141 to actuator module 139 which in turn operates the bow thruster 136 via actuation signal 140 for vessel manoeuvres such as vessel rotation and sideways translations.

By way of example, Figure 11 shows how the bow thruster 136 may supplement the six basic low speed manoeuvres shown in example 1. As indicated in Figure 11, the bow thruster provides additional lateral forces on the bow of the vessel to assist rotational movements 3,4 (clockwise or anticlockwise) and sideways translations 5,6 (port or starboard) of the vessel. Table 2 below summarises the status of the steering deflectors and reverse ducts for the waterjet units 111 and the status of the bow thruster 136 for each of the six basic low speed manoeuvres. As indicated in Table 2, the steering deflectors are operated in synchronism, while the reverse ducts are operated in synchronism or differentially.

Example 3 -

Control Device for a Vessel with Multiple Waterjet Units and Lateral Thruster(s)

(Not Differential Thrust Capable)

As described in example 2 with reference to Figures 10 and 12, the control devices 100 and 200 can be arranged to operate a vessel driven by multiple waterjet units (having differential thrust capability) and a bow thruster to perform various low speed manoeuvres. However, the control devices 100 and 200 can also be arranged to control such a vessel without utilising differential thrust for manoeuvres such as sideways translations to port or starboard. This flexibility allows the control device to operate on a vessel in which the steering deflectors and reverse ducts of the waterjet units are only moveable in unison.

In this situation, the schematic arrangement is the same as that shown in Figure 10, but the control device 200 implements sideways translational movements in a different manner without the assistance of differential thrust. As shown in Figure 12, the surge translational movements 1,2 (ahead or astern) are the same as that shown in Figure 12. The rotational movements 3,4 (clockwise or anticlockwise) are also substantially the same, except there the thrust applied by each waterjet unit is identical as the reverse ducts move in unison. The sideways translational movements 5,6 are 0 different and are implemented via a combination of port or starboard thrust at the stern of the vessel produced by the waterjet units and corresponding port or starboard thrust at the bow of the vessel produced by the bow thruster. Table 3 below summarises the status of the steering deflectors and reverse ducts for the waterjet units and the status of the bow thruster for each of the six basic low speed manoeuvres referred to previously. As indicated in Table 3, the steering 5 deflectors and reverse ducts of the waterjet units are operated in unison for each basic manoeuvre.

TABLE 3: SUMMARY OF 6 BASIC VESSEL MANOEUVRES

Example 4 - Control System for a Vessel with Single Wateηet Unit and Lateral Thruster(s)

Referring to Figure 13, a schematic arrangement of the control system described above instaUed in a vessel propeUed by a single waterjet unit 111 is shown. The waterjet unit 111 is typicaUy placed in the center at the stern of the vessel and has the same assembly and componentry as was described in respect of the waterjet units in Figure 8. In the bow 135 of the vessel is a bow thruster 136 which is operable to produce lateral thrust forces to either port or starboard as indicated by thrust vectors 137,138 respectively.

The bow thruster 136 has, for example, an impeller driven by a reversible motor. The reversible motor is operated by an actuator module 139 which sends actuation signals 140 to control the speed and direction of the reversible motor and thereby the direction and magnitude of the lateral thrust produced by the bow thruster 136.

In operation, the control system controls the waterjet unit 111, engine 113, and bow thruster 136 via their respective actuation modules 125,139 to manoeuvre the vessel during, for example, low speed operations such as docking and setting off in a marina or the like. In particular, X-axis, Y-axis, and Z-axis signals 122 are generated in response to the manipulation of the control devices 100 and 200 by an operator. The signals 122 are received by a control system 123, and are processed and sent 124,141 to actuator modules 125,139 to operate the waterjet unit 111, engine 113, and bow thruster 136 to manoeuvre the vessel. As mentioned, the actuator module 125 generates actuation signals 126 which are input through ports 119, 120, 121 to control the engine throttle, and steering deflector and reverse duct of the waterjet unit 111, while actuator module 139 generates actuation signals 140 to control the speed and direction of the reversible motor of the bow thruster 136.

Figure 14 shows the same six basic low speed manoeuvres as in for example Figure 9, except for a single waterjet vessel with a bow thruster as illustrated in Figure 13. As with the twin waterjet vessel embodiments, the basic manoeuvres are enabled by the control system 100 and include four translations 1,2,5,6 in which the vessel moves ahead, astern, to port or to starboard respectively, while maintaining a constant compass heading. Figure 14 also shows two rotations 3,4 in which the vessel turns to port or starboard about a centre point in the vessel respectively and manoeuvres resulting from the operation of the control devices 102 and 200 in each case are shown.

The waterjet unit 111 and bow thruster 136 are operated as summarised in Table 2 below for the six basic manoeuvres. Virtually any movement of the vessel may be achieved by a combination of these basic manoeuvres.

Like the twin waterjet vessel embodiment described above, the control device may be equipped with one or more additional manuaUy operable control inputs for controlling gain, sensitivity, engine idle speeds, or any combination thereof. The additional control inputs may be in the form of a thumbwheel or alternatively any other manuaUy operable input device may be utilised, examples of which have been given.

The first control device 100 may also be operated to manoeuvre the single waterjet vessel with bow thruster at higher speeds when cruising by changing the control device from a low speed mode to cruise mode via operation of a button, switch or the like. Operation of the first and second control devices in the low speed mode has been described above with reference to Figure 14 and Table 2. When in cruise mode, the control system 123 (Figure 13) disregards the Y-axis signal which represents sway demand (transverse translational movements) from the second control device 200 and therefore completely disables the bow thruster to prevent lateral thrust being produced at higher speeds. The first control device 100 only controls the surge of the vessel and the yaw or steering of the vessel. In particular, the control system 123 operates the engine throttle 113 and reverse ducts 116 of the waterjet unit 111 in accordance with movement of the control device 100 in the X-axis to surge the vessel fore or aft as desired, and operates the steering

deflectof 115 in accordance with rotation of the first control element 102 about the Z-axis to yaw or steer the vessel to port or starboard as desired.

Like the twin waterjet vessel embodiment described above, the control device may be equipped with one or more additional manually operable control inputs for controlling gain, sensitivity, engine idle speeds, or any combination thereof. The additional control inputs may be in the form of a thumbwheel or alternatively any other manually operable input device may be utilised, examples of which have been given.

The first control device 100 may also be operated to manoeuvre the single waterjet vessel with bow thruster at higher speeds when cruising by changing the control device from a low speed mode to cruise mode via operation of a button, switch or the like. Operation of the first and second control devices in the low speed mode has been described above with reference to Figure 14 and Table 2. When in cruise mode, the control system 123 (Figure 13) disregards the Y-axis signal which represents sway demand (transverse translational movements) from the second control device 200 and therefore completely disables the bow thruster to prevent lateral thrust being produced at higher speeds. The first control device 100 only controls the surge of the vessel and tiie yaw or steering of the vessel. In particular, the control system 123 operates the engine throttle 113 and reverse ducts 116 of the waterjet unit 111 in accordance with movement of the control device 100 in the X-axis to surge the vessel fore or aft as desired, and operates the steering deflector 115 in accordance with rotation of the first control element 102 about the Z-axis to yaw or steer the vessel to port or starboard as desired.

It will be appreciated that the vessels described in examples 2-4 could additionally utilise one or more other lateral thrusters to assist the bow thruster and that all the lateral thrusters may be controlled by the control device according to the particular manoeuvre desired. For example, the vessels may have one or more bow thrusters and one or more stern thrusters that assist the waterjet unit(s) to manoeuvre the vessel as desired by the operator as they manipulate the control element 102 of the control device 100.

It will be appreciated that the control system of the invention can be implemented in a wide range of forms on a wide range of marine vessels. For example, the control system can be adapted to suit vessels which are propelled by one or more waterjet units, inboard or outboard motors, stern drives and those which have one or more bow and stern thrusters, whether

αtientated laterally or otherwise. Details of the vessels, the individual control components and the propulsion units will be well known to a skilled reader.

The foregoing description of the invention includes examples thereof. Modifications may be made thereto without departing from the scope of the invention as defined by the accompanying claims.