"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 deflector(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 control system for manoeuvring a marine vessel or at least alternative.

SUMMARY OF THE INVENTION

In a fkst aspect, the invention broadly consists of a propulsion and control system for a marine vessel comprising: 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 manipulable control element and an arrangement of one or more associated sensors responsive to force applied manually to the control element in the direction of at least one axis or about at least one axis, the control element also being manually movable in the direction of at least one other axis or about at least one other axis, the control device being arranged to generate a control signal or signals indicative of the direction(s) of movement of the control device and in which force or torque is applied to the control element by an operator; and an associated control system which operates the waterjet units to manoeuver the vessel in accordance with movement of and the direction of force applied to the control element.

Preferably, the control system operates the waterjet units so that displacement of the control element in one or more directions, or increasing force applied to the control element in one or more directions, causes a corresponding rate of movement for the vessel in the direction in which the control element is moved or in which force on the control element is applied, and rotation of the control element or torque applied to the control element by twisting the control element, either clockwise or anticlockwise, causes yaw of the vessel about a vertical axis.

In one form of the control device the control element is movable both in a fore-aft axis and rotatably to generate control signal(s) indicative of fore-aft movement and rotational movement of the control element, and the control device comprises an arrangement of one or more associated sensors responsive to force applied to the control element in a lateral axis to generate a control signal indicative of force applied to the control element in said lateral axis.

In another form of the control device the control element is movable in a fore-aft axis to generate control signal(s) indicative of fore-aft movement of the control element, and the control device comprises an arrangement of one or more associated sensors responsive to force applied to the control element both in a lateral axis and to rotational force or torque applied to the control element to generate control signals indicative of force applied to the control element in said lateral axis and rotational force.

In a further form of the control device the control element is movable in both a fore-aft axis and a lateral (port-starboard) axis to generate control signals indicative of fore-aft and lateral movement of the control element, and the control device comprises an arrangement of one or more associated sensors responsive to rotational force or torque applied to the control element to generate a control signal indicative of torque applied to the control element.

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

In a second aspect, the present invention broadly consists of a propulsion and control system for a marine vessel comprising: 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 manipulable control element and an arrangement of one or more associated sensors responsive to force applied manually to the control element in the direction of at least one axis or about at least one axis, the control element also being manually movable in the direction of at least one other axis or about at least one other axis, the control device being arranged to generate a control signal or signals indicative of the direction(s) of movement of the control device and in which force or torque is applied to the control element by an operator; and an associated control system which operates the waterjet unit(s) and lateral thruster(s) to manoeuver the vessel in accordance with movement of and the direction of force applied to the control element.

Preferably the control system operates the waterjet unit(s) and lateral thrusters(s) so that displacement of the control element or force applied to the control element in each axis causes a corresponding rate of movement for the vessel in a corresponding direction, and so that rotational force applied to the control element, or rotation of the control element, either clockwise or anticlockwise, causes yaw of the vessel about a vertical axis. 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 lateral thruster.

In a third aspect, the invention broadly consists in 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 manipulable control element that is manually manipulable with respect to at least two axes, and which control device includes an arrangement of one or more associated sensors responsive to force and/ or torque applied manually to the control element in the axes to generate a control signal or signals indicative of the direction(s) in which force and/ or torque is applied to the control element by an operator; and an associated control system which operates the waterjet units to manoeuvre the vessel in accordance with the direction of the force and/or torque applied to the control element.

The control device may be arranged so that when no force is applied to the control element the control system will operate the waterjet unit(s) and lateral thruster at zero thrust.

In a fourth 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 manipulable control element that is manually manipulable with respect to at least two axes, and which control device includes an arrangement of one or more associated sensors responsive to force and/ or torque applied manually to the control element in the axes to generate a control signal or signals indicative of the direction(s) in which force and/or torque is applied to the control element by an operator; and an associated control system which operates the waterjet unit(s) and lateral thruster(s) to manoeuvre the vessel in accordance with the direction of the force and/ or torque applied to the control element.

The control element may be manually manipulable with respect to three axes and the one or more associated sensors are responsive to force and/ or torque applied manually to the control element in tine three axes. For example, the control element may be manually manipulable with respect to x, y, and z axes, where the x-axis represents the desired ahead and astern translational movements of the vessel, the y-axis represents the desired port and starboard translational movements of the vessel, and the z-axis represents the desired rotational movements of the vessel to port and starboard.

The control system operates the waterjet units and any lateral thrusters(s) so that increasing force applied to the control element by an operator causes a corresponding rate of movement for the vessel in the direction in which the force on the control element is applied, and torque applied

to the control element, either clockwise or anticlockwise, causes yaw of the vessel about a vertical axis.

Alternatively, the control element may be manually manipulable with respect to two axes and the one or more associated sensors may be responsive to force and/or torque applied manually to the control element in the two axes. In one form, the control element may be manually manipulable with respect to x and y axes, where the x-axis represents the desired ahead and astern translational movements of the vessel and the y-axis represents the desired port and starboard translational movements of the vessel. In another form, the control element may be manually manipulable with respect to x and z axes, where the x-axis represents the desired ahead and astern translational movements of the vessel and the z-axis represents the desired rotational movements of the vessel to port and starboard.

The control device may be arranged so that when no force is applied to the control element the control system will operate the waterjet units and any lateral thrusters(s) at zero thrust.

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 any lateral thruster.

Preferably, the control system is arranged such that increasing force applied to the control element in a direction increases thrust for translational movements of the vessel in that direction. Similarly, increasing torque applied to the control element in a direction, either clockwise or anticlockwise, increases thrust for rotational movements of the vessel in that direction.

The control element is manipulable 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. The control device further may comprise a reference surface below the control element upon which the operator may rest a portion of their hand, wrist or fingers for stability during operation of the control element to manoeuvre the vessel. Alternatively the control element may be a stick control member or a rotatable ball control element.

In any of the aspects of the invention described above the control element is mounted about a vertical or approximately be a vertical axis.

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. The control device further may comprise a reference surface below the control element upon which the operator may rest a portion of their hand, wrist or fingers for stability during operation of the control element to manoeuvre the vessel. Alternatively the control element may be a stick control or a rotatable ball control element.

The system 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 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 fottns of the invention will be described by way of example only and with reference to the drawings, in which:

Figure 1 is a perspective view of a control device of one form of propulsion and control system of the invention;

Figure 2 is a perspective view of the control device being operated;

Figure 3 is a perspective view of the structural components supporting the control element of the control device;

Figure 4 is a plan view of the control device showing the control element in a full ahead position with slight rotation to port;

Figure 5 is a plan view of the control device showing the control element in a full port position with slight rotation to port; Figure 6 is a perspective view of an alternative control element 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 shows one form of post-top mounted control device; Figure 9 is a perspective view of the control device of Figure 8 separate from the post shown in

Figure 8;

Figure 10 is a cross-section view of the control device of Figure 9 along line I-I of Figure 9;

Figure 11 is a perspective view of a strain pillar of the control device of Figures 9 and 10;

Figure 12 shows one form of console mounted control device; Figure 13 is a schematic diagram of a propulsion and control system comprising twin waterjet units on a marine vessel;

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

Figure 13;

Figure 15 shows a sideways manoeuvre to port for the twin waterjet unit shown in Figure 13; Figure 16 shows a schematic diagram of a propulsion and control system comprising twin waterjet units and a bow thruster on a marine vessel;

Figure 17 shows a number of fundamental manoeuvres which are possible with the system of

Figure 16, some of which use differential thrust;

Figure 18 shows a number of fundamental manoeuvres which are possible with the system of Figure 16, none of which use differential thrust;

Figure 19 is a schematic diagram of a propulsion and control system comprising a single waterjet unit, and a bow thruster on a marine vessel;

Figure 20 shows a number of fundamental manoeuvres which are possible with the system of Figure 19 Figure 21 is a schematic diagram of a propulsion and control system comprising twin waterjet units on a marine vessel;

Figure 22 shows a number of fundamental manoeuvres which are possible with the system of Figure 21;

Figure 23 shows a sideways manoeuvre to port for the twin waterjet unit shown in Figure 21; Figure 24 shows a schematic diagram of a propulsion and control system comprising twin waterjet units and a bow thruster on a marine vessel; and

Figure 25 shows a number of fundamental manoeuvres which are possible with the system of Figure 24, some of which use differential thrust.

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 Figures 1 and 2, in the embodiment shown the control device 100 is provided with a housing 101 which supports a control element 102 which in this embodiment has a shape representative of a vessel. The shape of the control element 102 may be varied and it 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 manipulable or within an X-Y plane and/ or clockwise or anticlockwise about a Z-axis. Generally, the Z-axis is perpendicular to the X-Y plane. The control element preferably has toward a neutral position with respect to the axes in which the control element is manipulable.

In an alternative embodiment the control device and element may comprise a stick control member such as a three-axis joystick (a joystick moveable in x and y axes and rotatable about its centre/a z-axis), or a rotatable ball control element such as a spaceball with outputs limited to the x, y and z-axis.

A control system associated with the control device operates the vessel's propulsion units and/ or any lateral thrusters to manoeuvre the vessel in accordance with displacement of and force applied to the control element 102. In particular, the control system operates the vessel's propulsion units so that displacement of and force applied to the control element 102 causes a corresponding rate of movement of the vessel. For example, if the control element is movable in the X-axis, relative to the neutral position, displacement of the control element 102 along the X- axis of the plane causes a corresponding fore or aft translational movement (surge) of the vessel. Displacement of the control element 102 or operator force applied to the control element along the Y-axis of the plane causes a corresponding port or starboard translational movement (sway) of the vessel. Rotation of the control element 102 or rotational force applied to the control element by the operator, clockwise or anticlockwise, about its Z-axis causes a corresponding yaw movement of the vessel. Further, the control device can be operated to perform any combination of surge, sway and yaw movements simultaneously to manoeuvre the vessel as desired.

In the embodiment shown by way of example in Figures 1 to 5, the control element is movable in the X and Y axes and the control device is responsive to rotational force on the control element about the Z axis. The control element 102 is mounted to a shaft or pillar 105 (shown in Figure 3) which protrudes through a shaped aperture 104 in top cover 103 of the housing 101. Referring to Figure 3, an arrangement of strain gauges 150 are mounted to the shaft 105 to generate a Z-axis signal representing 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 an upper plate 106 which is in turn slidably mounted to a lower plate 107 via transverse slides 108. The transverse slides 108 enable the upper plate 106 to move left and right relative to the lower plate 107 and thereby enable the control element 102 to move along the Y-axis of its movement plane. The lower plate 107 is slidably mounted to a fixed base 109 of the housing 101 via longitudinal slides 110 which enable the control element 102 to move along the X-axis of its movement plane. Spring mechanisms and linear potentiometers are provided between the fixed base 109 and the lower plate 107, and between the lower plate 107 and the upper plate 106. The spring mechanisms bias the control element 102 toward a central position

(neutral position) when it is not being operated, while the linear potentiometers generate X-axis and Y-axis signals which represent the position of the control element 102 relative to the neutral position.

As mentioned, the shaft or pillar 105, onto which the control element 102 is mounted, protrudes through a shaped aperture 104 in a top cover 103 of the housing 101. Referring to Figure 4, the shaped aperture 104 is preferably generally diamond-shaped and restricts the movement of the control element 102 in the X-Y plane. This ensures limited sideways displacement (sway) when the control element 102 is in the full ahead (as shown in Figure 4) or full astern positions. Likewise, when the control element is fully to port (as shown in Figure 5) or starboard, the diamond-shaped aperture allows only a limited range of ahead and astern displacement. Alternatively, other shaped apertures may be utilised to restrict the range of movements of the control element 102 as desired.

It will be appreciated that there are various other mechanical, electrical and electronic arrangements which may be utilised to sense the displacement of the control element 102 relative to the neutral position to thereby generate the X-axis or Y-axis signals, such as magnetic, inductive, or optical technologies. In other embodiments where the control element may move rotationally about the Z-axis similar technologies may be used or the shaft or pillar 105 or equivalent may comprise a rotary potentiometer. Further it will be appreciated that other mechanical arrangements may be utilised which enable the control element 102 to be displaced in a plane and to rotate about an axis and the control device need not necessarily include slidable plates and/ or rotatable potentiometers for this purpose.

In response to the X-axis, Y-axis, and Z-axis signals, the control system operates the vessel's propulsion units to cause the vessel to surge, sway and/ or yaw in accordance with the position of and rotational force applied to the control element 102. In particular, the vessel rate of movement is determined by the position of the control element 102 relative to the neutral position in the X-Y plane and force applied to the control element about the Z-axis. For example, if the operator wants the vessel to surge forward, the operator simply moves and holds the 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 units. Similarly, to cause a translational movement of the vessel in the transverse direction, the control element 102 is displaced in a sideways direction along the Y-axis. If the operator requires to rotate the vessel, the operator applies rotational force to the control element, 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. Essentially, the control system of the control device 100 will cause the vessel's movement to mimic the displacement of and the force applied to the control element 102.

A vast range of vessel manoeuvres are possible by manipulation of the control device 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. To achieve these combination-manoeuvres the control element 102 is simply moved to the desired position within the X-Y plane and/or twisted about its Z-axis. The proportions of each of the fundamental surge, sway and yaw movements which contribute to the final vessel manoeuvre depend on the position of the control element 102 relative to its neutral position in the X-Y plane and force applied to the control element about the Z-axis. In particular, the further the control element 102 is from its neutral position relative to the X-Y plane and the greater the rotational force applied about the Z-axis, the more thrust is demanded for the respective surge, sway and yaw movements.

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 control element 102. As mentioned, the X-axis and Y-axis signals represent the position of the control element 102 relative to the neutral position in the X-Y plane, while the Z-axis signal represents the torque applied to the control element 102 about its Z-axis. 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 pre-programmed to operate the or each propulsion unit in combination or alone to manoeuvre the vessel in accordance with the operation of the control element 102. In particular, the control system is programmed to operate the vessel's propulsion units to cause the vessel to move in a manner which mimics the operator's manipulation of the control element 102.

At or towards the outer extent(s) of movement of the control element in any of the axes 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 on one or both sides of the neutral position 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 force sensors may be provided at or towards the limits of movement of the control element in any axis again at one or both ends 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.

Figure 6 shows an alternative form of the control device which, along with the control element 102, has an additional manually operable control input in the form of a thumbwheel 200 embedded in the top surface of the control element 102. The thumbwheel 200 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 200 may, for example, be arranged as a gain control for controlling the level of thrust which is demanded in response to manipulation of the control element 102. In particular, the thumbwheel 200 may be operated to control the relationship between manipulation of the control element 102 in the X, Y, and Z axes with respect to the neutral position and the level of thrust demanded. By way of example, the position of the thumbwheel 200 may determine the thrust demand for each degree of manipulation of the control element 102 with respect to the X, Y and Z axes and thereby provides the user with a means of setting the upper or maximum speeds attainable during a manoeuvre.

Figure 7a illustrates graphically how the thumbwheel 200, functioning as a gain control, may control the relationship between manipulation of the control element 102 with respect to the neutral position and the thrust level. By way of example, the thumbwheel may have five positions 201-205 and therefore five different gain settings, position 201 being the lowest gain setting and position 205 being the highest. As the thumbwheel 200 is rotated from position 201 to 205 the thrust level demand for each degree of manipulation of the control element in the X, Y and Z axes increases, and vice versa as the thumbwheel is rotated from position 205 to 201. Hence the thrust level for each degree of control element manipulation, and therefore the thrust level during any surge, sway, yaw or combination manoeuvre, will depend on the thumbwheel position.

It will be appteckted 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 200 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 205 (fast response time), the control system will operate the vessel's propulsion units to rapidly perform desired vessel manoeuvres in accordance with manipulation of the control element. Conversely, if the thumb wheel is positioned for lower sensitivity 201, 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 206 is a linear one in which the response time will alter linearly with respect to the thumbwheel position. The second relationship 207 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, die 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 200 may control the engine idle speed(s) of the vessel's propulsion unit(s) according to a linear 208 or non-linear 209 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 200 may be arranged to control other parameters and settings, or any combination thereof. For example, the thumbwheel 200 may be arranged to control both the gain and engine idle speed. With such an arrangement, the

thumbwheel 200 would control the relationship between the degree of manipulation 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 200 from position 201 to a higher position (202-205) 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 device may also be used to manoeuvre vessels at higher speeds, for example when cruising. The 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 applied 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 control element in the Y-axis mechanically, although this is not essential.

Alternatively, the control element may be free to move in the Y-axis, but the Y-axis signal would be disregarded by the control system when the control device is in cruise mode.

In the preferred embodiment described above with reference to the drawings the control element 102 is movable in the fore-aft axis and laterally in the port-starboard axis, and is non- movable but the control device is responsive to rotational force about the Z-axis. In alternative embodiments the control element may be movable in the fore-aft axis and rotationally moveable about the Z-axis, and non-movable but responsive to force in the lateral port-starboard axis for example. Any configuration is possible, with an arrangement of one or more associated sensors responsive to movement of the control element in the direction of at least one axis or about at least one axis and responsive to force applied manually to the control element in the direction of at least one other axis or about at least one other axis, to generate control signals indicative of the directions of movement of the control device and in which force or torque is applied to the control element by an operator.

By "manipulation" in this specification in relation to the control element 102 is intended to include movement as well as 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.

Referring to Figures 8 and 9, in this alternative embodiment shown the control device 102 is mounted to the top of a post 110 beside which an operator carrying out for example slow speed manoeuvring of a vessel may stand, and comprises a control element 102 having a shape representative of a vessel. The shape of the control element 102 may be varied and it does not necessarily have to be vessel-shaped. Any shape which is operable by the hand of an operator would be suitable. In an alternative embodiment the control device and element may comprise a stick control member such as a three-axis joystick (a joystick moveable in x and y axes and rotatable about its centre/a z-axis), or a rotatable ball control element such as a spaceball with outputs limited to the x, y and z-axis. An arrangement of sensors may sense force applied to the spaceball in any of the x, y and z axes.

In this embodiment the control device is responsive to force on the control element in each axis. In particular, the control system operates the vessel's propulsion units so that increasing force

applied to the control element 102 causes a corresponding rate of movement of the vessel in the direction in which the force on the control element is applied. For example, relative to the neutral position, operator force applied to the control element 102 along the X-axis (see Figure 9) causes a corresponding fore or aft translational movement (surge) of the vessel, while operator force applied to the control element 102 along the Y-axis of the plane causes a corresponding port or starboard translational movement (sway) of the vessel. Rotational force or torque appEed to the control element 102 by the operator, clockwise or anticlockwise, about its Z-axis causes a corresponding yaw movement of the vessel. Further, the control device can be operated to perform any combination of surge, sway and yaw movements simultaneously to manoeuvre the vessel as desired.

In the embodiment shown by way of example, the control element 102 is mounted to a strain pillar 101 — see Figure 10, and Figure 11 which shows the strain pillar 101 separately. The strain pillar 101 comprises pillar component 103 to which are mounted strain gauges 106. Wires from the strain gauges 106 pass into a bore 108 through the center of the pillar 103 and down through bottom flange 104, to pass the output signals of the individual strain gauges 106 of the preferred embodiment, to the control system. In the embodiment shown the pillar component 103 has a square cross-section and thus four sides, and a strain gauge 106 is mounted to each side of pillar 103. Any other pillar configuration of strain gauges or other force sensitive device or devices may be utilised however, to provide a signal or signals which can be resolved to X-axis, Y-axis, and Z-axis signals from the control device.

In the preferred form the control element 102 is screwed via one or more mounting screws 107 to top flange 105 of the strain pillar 101, and the control element-strain pillar assembly is mounted in a desired location for example at the top of the post 110 shown in Figure 1, by the bottom flange 104, but any other suitable mechanical arrangement may be used.

When the operator applies fore or aft force to the control element 102 along the X-axis, an X-axis output signal from the configuration of strain gauge(s) 106 is generated, proportional to the degree of force applied by the operator to the control element 102 in that axis. Similarly, when the operator applies force to the control element 102 in the Y-axis, a Y-axis output signal is generated from the strain gauge(s) 106, the signal level again being proportional to the degree of force applied by the operator. Typically the higher the degree of force applied by the operator along any axis, the higher the amplitude of the output signal from the strain gauge(s) 106, but in an alternative embodiment where an alternative form of force sensitive device is used for example, instead the

frequency of the output signal from the force sensitive device may vary in proportion to the degree of force applied to the control element 102 by the operator, or the output signal of the force sensitive device(s) may be otherwise modulated in some way proportional to the force applied by the operator. When the operator applies torque to the control element 102, to port or to starboard, about the Z-axis, the output signal(s) generated by the strain gauge(s) 106 are again indicative of such torque, again also proportional to the degree of torque applied. 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.

It should be noted however that it is not intended to exclude that a mechanical arrangement may be provided which will cause the user to feel a small mechanical "click" or feel a small degree of initial movement of the control element on initially pressing the control element in any axis, to provide sensory feedback to the operator. Alternatively and/ or additionally a low volume audible "beep " or other tone may be provided, again to provide a response to the operator that the system has been engaged by the applied pressure.

In response to the X-axis, Y-axis, and Z-axis signals, the control system operates the vessel's propulsion units to cause the vessel to surge, sway and/or yaw in accordance with the force applied to the control element 102. In particular, the vessel rate of movement is determined by the force applied to the control element 102 relative to a neutral position in the X-Y plane and the Z- axis. For example, if the operator wants the vessel to surge forward, the operator simply presses forwardly against the control element 102 in the direction of the X-axis. The more force applied, the more thrust is produced in that direction by the vessel's propulsion units. Similarly, to cause a translational movement of the vessel in the transverse direction, force is applied against the control element 102 in a sideways direction along the Y-axis. If the operator requires to rotate the vessel, torque is applied to the control element, 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. Essentially, the control system of the control device 100 will cause the vessel's movement in the direction of and proportional to the force applied by the operator of the control element 102. The proportions of each of the fundamental surge, sway and yaw movements which contribute to the final vessel manoeuvre depend on the force applied to the control element 102 relative to its

neutral position (no force applied to the control device in any direction by the operator) in the X-Y plane and torque about the Z-axis.

The control system receives and processes the X-axis, Y-axis and Z-axis signals generated by the control element to determine the desired manoeuvre required by the operator, and generates and sends control signals to the vessel's propulsion units to manoeuvre the vessel in a manner which mimics the operator's manipulation of the control element 102.

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

(Differential Thtust Capable) - 3 Axis Control Device Movable in X and Y axes and Force

Responsive in Z-Axis

Referring to Figure 13, a schematic arrangement of the control device 100 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 device 100 is shown as the only manual control device 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 the movement of and rotational force applied to the control element 102 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

conttol the engine thtottle, and steeling deflector and reverse duct of each waterjet unit. While the control device 100 is shown as hardwired to the actuator modules 125, alternatively the control device 100 may, for example, be a remote unit which communicates with the vessel's control system and/ or actuator modules via a wireless link.

Figure 14 shows six basic low speed manoeuvres of a vessel which may be enabled by the control device 100. 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 element 102 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. The control device is intended to allow an operator to use the control element 102 in a simple intuitive fashion to cause movement of the vessel i.e. the vessel's movement mimics manipulation of the control element 102.

Displacing the control element 102 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-Y plane, applying clockwise or anticlockwise rotational force to the control element 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. Displacing the control element 102 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 (i.e. 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.

Figure 15 schematically shows a vessel 127 with a twin waterjet arrangement and control device 100 according to the invention. A sideways manoeuvre to port is in progress, such as manoeuvre 5 indicated in Figure 14. Nozzles 128, steering deflectors 129 and one of the reverse ducts 130 are shown at the stern of the vessel to indicate the port and starboard waterjets. The reverse duct on the starboard waterjet is not positioned to deflect the water flow from that jet and has been omitted from view. The control element 102 of the control device 100 has been pushed to port by the operator. This produces jet streams 131 from the waterjets and consequently thrust vectors 132. The net sideways force acts at a point 133 towards the center of the vessel represented by thrust vector 134.

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 control device may also be operated to manoeuvre the twin waterjet vessel at higher speeds when cruising. As mentioned above, the 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 control device in the low speed mode has been described above with reference to Figure 14 and Table 1. When in cruise mode, the control system 123 (Figure 13) disregards the Y-axis signal which represents sway demand (transverse translational movements) and therefore does not operate the waterjet units 111 to produce differential thrust. The control element 102 only 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 waterj et units 111 in a synchronised manner in accordance with force on the control element 102 in the X-axis to surge the vessel fore and aft as desired, and operates the steering deflectors 115 in accordance with rotational force applied to the control element 102 about the Z-axis to yaw or steer the vessel to port or starboard as desired. It will be appreciated that in cruise mode, the control element 102 may alternatively be disabled with respect to movement in the Y-axis to disable sway thrust at higher speeds.

Example 2 - Control Device fot a Vessel with Multiple Waterjet Units and Lateral Thtuster(s)

(Differential Thrust Capable)

Figure 16 shows a variant of the schematic arrangement described with reference to Figures 13-15 in which the control device 100 also controls a lateral thruster, such as a bow thruster 136, to 5 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. 0 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.

5 In operation, the control device 100 controls the water] et units 111 and engines 113 in the same manner as described above in relation to example 1. In addition, the control device 100 controls the bow thruster 136 for particular vessel manoeuvres. In particular, the control device 100 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. 0

By way of example, Figure 17 shows how the bow thruster 136 may supplement the six basic low speed manoeuvres shown in example 1. As indicated in Figure 17, 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 5 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 Watetjet Units and Lateral Thruster(s)

(Not Differential Thrust Capable)

As described in example 2 with reference to Figures 16 and 17, the control device 100-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 device 100 can also be arranged to control such a vessel without utilising differential thrust for 0 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 16, but the 5 control device 100 implements sideways translational movements in a different manner without the assistance of differential thrust. As shown in Figure 18, the surge translational movements 1,2

(ahead or astern) are the same as that shown in Figure 17. 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 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 deflectors and reverse ducts of the waterjet units are operated in unison for each basic manoeuvre.

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

Referring to Figute 19, a schematic arrangement of the control device 100 described above installed in a vessel propelled by a single waterjet unit 111 is shown. The waterjet unit 111 is typically 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 13. 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 device 100 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 fore-aft, port-starboard, and rotational force applied to the control element 102 of the control device 100 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 20 shows the same six basic low speed manoeuvres shown previously, except for a single waterjet vessel with a bow thruster as illustrated in Figure 19. As with the twin waterjet vessel embodiments of examples 1-3, the basic manoeuvres are enabled by the control device 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 20 also shows two rotations 3,4

in which the vessel turns to port or starboard about a center point in the vessel respectively and manoeuvres resulting from the force applied to the control element 102 in each case are shown.

The waterjet unit 111 and bow thruster 136 are operated as summarised in Table 4 below for the six basic manoeuvres. Virtually any movement of the vessel may be achieved by a combination of these basic manoeuvres. As shown in Figure 15, the control system operates the waterjet unit 111 and bow thruster 136 to cause the vessel to move in such a way that mimics the manipulation of the control element 102.

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 control device 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 control device in the low speed mode has been described above with reference to Figure 20 and Table 4. When in cruise mode, the control system 123 (Figure 19) disregards the Y-axis signal which represents sway demand (transverse translational movements) and therefore completely disables the bow thruster to prevent lateral thrust being produced at higher speeds. The control element 102 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 force applied to the control element 102 in the X-axis to surge the vessel fore or aft as desired, and operates the steering deflector 115 in accordance with rotational force applied to the control element 102 about the Z-axis to yaw or steer the vessel to port or starboard as desired. It will be appreciated that in cruise mode, the control element 102 may alternatively be mechanically constrained with respect to movement in the Y-axis to disable operation of the bow thruster at higher speeds.

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.

Example 5 -

3 Control Device for a Vessel with Multiple Waterjet Units (Differential Thrust Capable) - 3-Axis Control Device - Force Responsive in X, Y, Z Axes

Referring to Figure 21, a schematic arrangement of the control device 100 described above installed in a vessel propelled by twin waterjet units 111 is as described in relation to example 1.

For clarity, the control device 100 is shown as the only manual control device 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 force applied to the control element 102 by an operator in these axes. 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 device 100 is shown as hardwired to the actuator modules 125, alternatively the control device 100 may, for example, be a remote unit which communicates with the vessel's control system and/ or actuator modules via a wireless link.

Figure 22 shows six basic low speed manoeuvres of a vessel which may be enabled by the control device 100. 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 22 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 element 102 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 5 below. Virtually any movement of the vessel may be achieved by a combination of these basic manoeuvres. The control device is intended to allow an operator to use the control element 102 in a simple intuitive fashion to cause movement of the vessel i.e. the vessel's movement mimics manipulation of the control element 102.

Ahead or astern force applied to the control element 102 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. Torque applied to the 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. Operator force on the control element 102 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 (i.e. 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 2-5.

Figure 23 schematically shows a vessel 127 with a twin waterjet arrangement and control device 100 according to the invention. A sideways manoeuvre to port is in progress, such as manoeuvre 5 indicated in Figure 22. Nozzles 128, steering deflectors 129 and one of the reverse ducts 130 are shown at the stern of the vessel to indicate the port and starboard waterjets. The reverse duct on the starboard waterjet is not positioned to deflect the water flow from that jet and has been omitted from view. Force has been applied to port against the control element 102 of the control device 100 by the operator. This produces jet streams 131 from the waterjets and consequently thrust vectors 132. The net sideways force acts at a point 133 towards the center of the vessel represented by thrust vector 134.

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 control device may also be operated to manoeuvre the twin waterjet vessel at higher speeds when cruising. As mentioned above, the control device may have a mode change button or the Eke for switching between a low speed mode and a cruise mode. Operation of the control device in the low speed mode has been described above with reference to Figure 22 and Table 5. When in cruise mode, the control system 123 (Figure 21) disregards the Y-axis signal which represents sway demand (transverse translational movements) and therefore does not operate the waterjet units 111 to produce differential thrust. The control element 102 only 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 operator force on the control element 102 in the X-axis to surge the vessel fore and aft as desired, and operates the steering deflectors 115 in accordance with torque applied to the control element 102 with respect to the Z-axis to yaw or steer the vessel to port or starboard as desired. It will be appreciated that in cruise mode, the Y-axis signal from the control element 102 may be disabled to disable sway thrust at higher speeds. In a 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 the control element in the reverse direction in the X-axis.

Example 6 —

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

(Differential Thrust Capable)

Figure 24 shows a variant of the schematic arrangement described with reference to Figures 21-23 in which the control device 100 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 device 100 controls the waterjet units 111 and engines 113 in the same manner as described above in relation to example 1. In addition, the control device 100 controls the bow thruster 136 for particular vessel manoeuvres. In particular, the control device

100 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 25 shows how the bow thruster 136 may supplement the six basic low speed manoeuvres shown in example 5. As indicated in Figure 25, 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 6 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 6, the steering deflectors are operated in synchronism, while the reverse ducts are operated in synchronism or differentially.

It will be appreciated that the control device of the invention can be implemented in a wide range of forms on a wide range of marine vessels. For example, the control device 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 orientated 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.