Thruster system for marine vessels

Abstract

A boat comprises a hull, a primary steering mechanism carried by the hull, a control station located on the hull, a helm located at the control station, and a thruster system carried by the hull. The primary steering mechanism, such as a rudder, is operable via the helm with a helm input being derived from operation of the primary steering mechanism thereby. The thruster system includes at least one thruster mounted to the hull, distinct from the primary steering mechanism, and a controller. The controller receives the helm input and is configured with program instructions to operate the at least one thruster responsive to the helm input to supplement a corresponding movement of the hull. The controller can also automatically operate the thruster responsive to direction, speed and ballast inputs.

Claims

1. A method of improving turning performance of a boat steered by a rudder while moving under power of an inboard motor, the method comprising: receiving, at a controller, a rudder input indicating a turning direction of the rudder and a speed input indicative of a speed of the boat; automatically operating a thruster of the boat to supplement a turning motion of the boat in a direction indicated by the turning direction of the rudder including varying a speed of the thruster proportionally with the magnitude of the turning of the rudder.

2. The method of claim 1, wherein the rudder input further indicates a magnitude of a turning of the rudder; and wherein automatically operating the thruster of the boat to supplement the turning motion of the boat in the direction indicated by the turning direction of the rudder includes varying a speed of the thruster proportionally with the magnitude of the turning of the rudder.

3. The method of claim 1, wherein automatically operating the thruster of the boat to supplement the turning motion of the boat in the direction indicated by the turning direction of the rudder further includes securing thruster operation when the speed of the boat is above a predetermined upper speed threshold.

4. The method of claim 1, wherein the speed input is derived from monitoring a speed of the inboard motor.

5. The method of claim 1, wherein the speed input is derived from a water speed sensor.

6. The method of claim 1, wherein the speed input is derived from global positioning system (GPS) data.

7. The method of claim 1, further comprising: receiving, at the controller, a direction input indicating forward or reverse operation of the inboard drive; wherein automatically operating the thruster of the boat to supplement the turning motion of the boat in the direction indicated by the turning direction of the rudder includes changing a thrust direction of the thruster based on the forward or reverse operation of the inboard drive.

8. The method of claim 7, wherein the thruster is a bow or stern thruster oriented athwartships and changing the thrust direction of the thruster based on the forward or reverse operation of the inboard drive includes reversing an operating direction of the thruster.

9. The method of claim 1, wherein the rudder input is derived from monitoring a position of the rudder.

10. The method of claim 1, wherein the rudder input is derived from monitoring a helm position of the boat.

11. The method of claim 1, further comprising: receiving, at the controller, an input indicative of a change in mass of the boat; wherein automatically operating the thruster of the boat to supplement the turning motion of the boat in the direction indicated by the turning direction of the rudder includes varying a speed of the thruster proportionally with the change in mass.

12. The method of claim 11, wherein the input indicative of a change in mass of the boat is a ballast level input.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic side view of a boat with a thruster system, according to an embodiment of the present invention; and

(2) FIG. 2 is a schematic overview of the thruster system of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(3) According to an embodiment of the present invention, referring to FIGS. 1 and 2, a boat 10 is equipped with a thruster system 12. The thruster system 12 includes at least one thruster 14 operable to impart a degree of lateral motion to a portion of the boat 10. A controller 16 directs operation of the thruster 14, preferably via a proportional drive 20 allowing variable speed operation. The controller 16 is configured to operate the thruster 14 automatically in response to helm input.

(4) In a preferred embodiment, the boat 10 includes a rudder 22 controlled by a helm 24 located at a control station 26. The rudder 22 is positioned aft of a propeller 30 driven by shaft 32 via an inboard motor. Advantageously, the helm input used by the controller 16 for automatic operation of the thruster is derived via monitoring of the rudder 22 position. Other helm inputs could be used, however. For instance, position of the helm 24, itself, could be detected. Additionally, the thruster system 12 could be used to supplement steering in boats with a primary steering mechanism other than a rudder, such as in boats with outboard motors or jet drives, airboats, etc., although superior low speed maneuvering is typically inherent in such vessels.

(5) In the depicted embodiment, the thruster 14 is a stern thruster fixedly mounted to the stern 34 of the hull 36 of the boat 10 at a point below the waterline and oriented athwartship, such that operation in opposite directions will urge the stern 34 to port and starboard, respectively. Alternately, or in addition to, a stern thruster 14, other thrusters (such as a bow thruster 14A) could be used. In general, the controller 16 is configured to automatically operate any thrusters 14 (14A) in response to the helm input such that a movement of the hull corresponding to the detected helm input is supplemented. For example, in the boat 10 equipped with the stern thruster 14, if the boat 10 is making headway and the helm 24 is turned to port, the controller 16 will operate the stern thruster 14 to urge the stern 34 to starboard.

(6) To this end, the controller 16 is advantageously further configured to distinguish between forward and aft operation when automatically operating the thruster 14 (14A) using a direction input. For instance, the controller 16 receives a direction input derived from throttle position (i.e., forward and reverse). Consistent with the principles described above, when the direction input indicates movement astern (in the boat 10 equipped with the stern thruster 14), if the helm 24 is turned to port, the controller 16 will operate the stern thruster 14 to urge the stern 34 to port. Such control can be based simply on receipt of a helm input to port or starboard above a predetermined input threshold. In addition to a direction of the helm input, a magnitude of the helm input above the threshold could be employed, as will be described in greater detail below.

(7) At higher speeds it may not be desirable to operate the thruster 14 (14A), or it may be desirable to operate the thruster at a lower speed. Accordingly, the controller 16 is further configured to automatically operate the thruster 14 (14A) responsive to a speed input. The speed input is derived for a global positioning system (GPS) determined speed, a water speed sensor, an engine speed or the like. Above a predetermined upper speed threshold, the controller 16 is preferably configured not to automatically operate the thruster 14 (14A). Other, lower speed thresholds could be used to automatically increase thruster 14 (14A) output as speed decreases and/or thruster speed control could be varied in inverse proportion with vessel speed up to the upper speed threshold.

(8) Some vessels, such as watersports boats, are equipped with ballasting systems. In such vessels, the controller 16 is preferably configured to automatically operate the thruster 14 (14A) responsive to a ballast input. For example, with ballast level detected above a predetermined level threshold, the controller 16 automatically increases thruster speed to compensate for the effect of the additional ballast.

(9) In addition to controlling thruster speed based on a vessel speed input and a ballast input, the controller 16 can be further configured to vary thruster speed based on the magnitude of the helm input. For example, if the helm input in a given direction (i.e., port or starboard) is greater than a predetermined threshold, the controller will automatically increase thruster 14 (14A) speed. Multiple thresholds could be employed or speed could be varied continuously over a range of helm input up to a predetermined maximum speed (which could be dependent on vessel speed, ballast level, etc.). Alternately, the controller 16 could simply operate the thruster at a single predetermined speed once helm input in a given direction is detected beyond a minimum threshold, regardless of the magnitude of input past that point.

(10) Cavitation can occur while accelerating or decelerating the thruster 14 (14A), which may result in decreased performance and increased wear on thruster mechanical and electrical components. Advantageously, the controller 16 can also be configured to constrain the rate at which the thruster accelerates or decelerates to an automatically- or manually-ordered speed in order to prevent cavitation. For example, the controller can set a rate of 5% of rated speed per 100 milliseconds for all speed changes. As a safety measure, an ordered speed of 0% is preferably implemented immediately without limitation.

(11) The system 12 preferably further includes a user interface device 40, such as a touch screen and/or multi-function controller. Via the user interface device 40, an operator of the boat 10 can opt to enable or disable automatic control of the thruster 14 (14A) via the controller 16. Advantageously, the operator can also set the thruster 14 for manual control responsive to a manual control input. The manual control input can be derived via any desired input device, such as a dedicated joystick, a multi-function controller (MFC), touch screen icons, etc. When operated manually, the manual control inputs can be processed via the controller 16 or transmitted directly to the proportional drive 20 (or other drive) of the thruster 14 (14A).

(12) Where a multi-function controller (MFC is used for the manual control input, the controller 16 can be configured to switch the MFC in and out of a manual control input mode. For example, a rotary encoder can normally be used to navigate between menu options of the user interface, but when manual control of the thruster is selected, the controller will tie clockwise and counter-clockwise rotation of the encoder to changing an ordered thruster speed.

(13) Via the user interface device 40, the operator is preferably also able to vary operational settings of the controller 16 when operating the thruster 14 (14A) automatically. For example, a user setting input can be used to select a speed or speed range at which the controller 16 operates the thruster 14 (14A). Additionally, threshold values applicable to helm, direction, speed and/or ballast inputs could be varied via the user setting input.

(14) Some boats 10 are equipped with an exhaust port 42 that vents engine exhaust below the waterline at the stern 34. With a stern thruster 14, such exhaust can result in cavitation of the thruster. Such cavitation may be avoided by cowling the thruster and/or vectoring engine exhaust away therefrom. Alternately, a second exhaust port 44 can employed for use during thruster 14 operationfor example an exhaust port 44 venting above the waterline. Other locations for the second exhaust port could be used, either above or below the waterline, provides that exhaust was vented in a position where it would not interfere with operation of the stern thruster. For example, the second exhaust port could be located closer to the bow.

(15) A crossover device 50 is configured to automatically switch between the exhaust ports 42, 44. The switching can be directed by the controller 16 based on thruster operation or be effected automatically (e.g., based on differing backpressure at different engine speeds).

(16) It will be appreciated that the thruster system 12 of the present invention affords intuitive thruster control in a manner that reduces demands on the marine vessel operator. In addition to eliminating the need for separate, manual control inputs to actuate a thruster, the system automatically takes into account other potentially relevant factors impacting thruster operation and vessel handling.

(17) Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within and of the claims appended hereto.