WO2023137039A1 - Modifying marine vessel propulsor steering angle - Google Patents

Abstract

An apparatus for modifying an effective steering angle of a steerable propulsor of a marine vessel includes a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle. The structure is configured to be attached to a steering nozzle of the steerable propulsor, positioned within the stream after the stream has exited the steerable propulsor, or both, or attached to a transom. The structure may comprise a deflector or an interceptor.

Description

MODIFYING MARINE VESSEL PROPULSOR STEERING ANGLE

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. § 119(e) of provisional application 63/298,607, filed January 11, 2022, titled “INCREASED MARINE VESSEL PROPULSOR STEERING ANGLE,” and provisional application 63/343,895, filed May 19, 2022, titled “INCREASED MARINE VESSEL PROPULSOR STEERING ANGLE,” each of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The apparatus and techniques described herein relate to control of marine vessels.

BACKGROUND

Marine vessels may include a propulsion system that includes one or more propulsors that propel the marine vessel through the water. Non-limiting examples of propulsors include propellers and waterjets. Some propulsors are steerable, which allows changing the angle of the induced thrust. Steerable propulsors may have their steering angle controlled to cause the marine vessel to perform a turning maneuver, or to perform other maneuvers. Steerable propulsors may be controlled to pivot about an axis to change the angle of induced thrust. For example, a waterjet may have a steering nozzle that is controlled by an actuator to pivot about a pivot point to change the angle of a stream exiting the steering nozzle. Similarly, a steerable propeller may be controlled to pivot about a pivot point to change the angle at which the propeller is positioned. The angle relative to the midline of the marine vessel at which thrust is directed by the stream produced by a propulsor is termed the “steering angle” of the propulsor.

SUMMARY

According to some aspects, an apparatus for modifying an effective steering angle of a steerable propulsor of a marine vessel may include a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle. The structure may be configured to be: A) attached to a steering nozzle of the steerable propulsor; and/or B) positioned within the stream after the stream has exited the steerable propulsor.

According to some aspects, an apparatus for modifying an effective steering angle of a steerable propulsor of a marine vessel may include a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle. The structure may be configured to be: A) attached to a steering nozzle of the steerable propulsor; and/or B) positioned within the stream after the stream has exited the steerable propulsor, wherein the at least a portion of the stream deflected by the structure has a directional component in an aft direction of the marine vessel.

The structure may comprise a deflector or an interceptor.

The structure may comprise a deflector including at least one vane.

The structure may be configured to move to change the effective steering angle of the steerable propulsor.

The structure may be configured to move in a direction toward or away from the stream.

The structure may be configured to be actuated in a direction toward or away from the stream.

The structure may be configured to be permanently attached to the marine vessel or detachable.

The structure may be configured to be attached to the steering nozzle.

The structure may be configured to move with the steering nozzle.

The structure may be configured to be attached to an inside of the steering nozzle.

The structure may be configured to be attached behind the steerable propulsor.

The structure may comprise an interceptor.

The interceptor may be curved or straight.

The structure may be configured to be positioned within the stream after the stream has exited the steerable propulsor.

The at least a portion of the stream deflected by the structure may have a directional component in an aft direction of the marine vessel.

The structure may be configured to be attached to a transom of the marine vessel or a steering nozzle of the steerable propulsor.

The structure may configured to be attached to a transom of the marine vessel and may comprise at least one vane.

The steerable propulsor may comprise a steerable propeller. The structure may not include a reversing deflector.

The structure may maintain a forward-aft directional component of the at least a portion of the stream primarily in the aft direction of the marine vessel.

Some aspects relate to a marine vessel comprising the apparatus and the steerable propulsor.

The marine vessel may further include a second steerable propulsor; and a second structure configured to deflect at least a portion of a second stream produced by the second steerable propulsor to modify an effective steering angle of the second steerable propulsor, the second structure being configured to be: C) attached to a steering nozzle of the second steerable propulsor; and/or D) positioned within the second stream after the second stream has exited the second steerable propulsor, wherein the at least a portion of the second stream deflected by the second structure has a second directional component in the aft direction of the marine vessel.

Some aspects relate to a method of controlling the apparatus or marine vessel of any preceding claim.

Some aspects relate to a method for modifying an effective steering angle of a steerable propulsor of a marine vessel. The method includes attaching, to the marine vessel, a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle. The attaching comprises A) attaching the structure to a steering nozzle of the steerable propulsor; B) attaching the structure to the marine vessel such that the structure is positioned within the stream after the stream has exited the steerable propulsor, wherein the at least a portion of the stream deflected by the structure has a directional component in an aft direction of the marine vessel; or C) both A) and B).

Some aspects relate to a method for modifying an effective steering angle of a steerable propulsor of a marine vessel. The method includes moving a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, wherein the at least a portion of the stream deflected by the structure has a directional component in an aft direction of the marine vessel.

Some aspects relate to a control system for a marine vessel. The control system includes a processor configured to receive a steering command for the marine vessel, and, when the steering command commands zero steering angle or a steering angle below a threshold, the processor is configured to control a steering nozzle to angle the steering nozzle such that an interceptor of the steering nozzle is positioned in a direction away from a stream flowing through the steering nozzle.

When the steering command commands zero steering angle or a steering angle below a threshold, the processor may be configured to control the steering nozzle to angle the steering nozzle such that the interceptor is positioned out of a stream flowing through the steering nozzle.

When the steering command commands zero steering angle or a steering angle below a threshold, the processor may be configured to control the steering nozzle to angle the steering nozzle at an angle of 1-10° with respect to a midline of the marine vessel.

Some aspects relate to a method of operating a control system of a marine vessel. The method includes receiving, by a processor, a steering command for the marine vessel; and when the steering command commands zero steering angle or a steering angle below a threshold, controlling, by the processor, a steering nozzle to angle the steering nozzle such that an interceptor of the steering nozzle is positioned in a direction away from a stream flowing through the steering nozzle.

When the steering command commands zero steering angle or a steering angle below a threshold, the processor may control the steering nozzle to angle the steering nozzle such that the interceptor is positioned out of a stream flowing through the steering nozzle.

When the steering command commands zero steering angle or a steering angle below a threshold, the processor may control the steering nozzle to angle the steering nozzle at an angle of 1-10° with respect to a midline of the marine vessel.

Some aspects relate to an apparatus for modifying an effective steering angle of a steerable propulsor of a marine vessel. The apparatus includes a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, the structure being configured to be: A) attached to a steering nozzle of the steerable propulsor; and/or B) positioned within the stream after the stream has exited the steerable propulsor, wherein the structure does not include a reversing deflector that is configured to be actuated into the stream to produce reverse thrust in response to a marine vessel thrust command in the astern direction.

Some aspects relate to a method for modifying an effective steering angle of a steerable propulsor of a marine vessel. The method includes attaching, to the marine vessel, a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle. The attaching comprises A) attaching the structure to a steering nozzle of the steerable propulsor; B) attaching the structure to the marine vessel such that the structure is positioned within the stream after the stream has exited the steerable propulsor, wherein the structure does not include a reversing deflector that is configured to be actuated into the stream to produce reverse thrust in response to a marine vessel thrust command in the astern direction; or C) both A) and B).

Some aspects relate to a method for modifying an effective steering angle of a steerable propulsor of a marine vessel, the method comprising: moving a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, wherein the structure does not include a reversing deflector that is configured to be actuated into the stream to produce reverse thrust in response to a marine vessel thrust command in the astern direction.

The foregoing summary is provided by way of illustration and is not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing.

FIG. 1 shows one example of a way in which the steering angle of a steerable propulsor may be constrained.

FIG. 2 shows examples of maneuvers that may not be achievable with steerable propulsors having a limited steering angle.

FIG. 3A shows a deflector as one example of a structure that can increase the effective steering angle of a steerable propulsor.

FIG. 3B illustrates the use of deflectors for the case where the steerable propulsors are steerable propellers.

FIG. 3C shows an example in which deflectors are positioned to the inboard side of their corresponding steerable propulsors.

FIG. 3D shows an example in which deflectors are positioned on both the inboard and the outboard sides of the steerable propulsors.

FIG. 4 shows an example of a deflector having a vane assembly.

FIG. 5A illustrates an interceptor inside of the steering nozzle on the inboard side to deflect the stream from the steering nozzle in an outboard direction. FIG. 5B shows an example in which interceptors are positioned on the outboard side of a steering nozzle.

FIG. 5C shows an example in which interceptors are positioned on the inboard side of a steering nozzle to deflect the stream from the steering nozzle in an outboard direction and interceptors are positioned on the outboard side of a steering nozzle to deflect the stream from the steering nozzle in an inboard direction.

FIG. 6 shows a perspective view illustrating an interceptor according to an example in which the steering nozzle and interceptor have a curved shape.

FIG. 7 illustrates a control system for a marine vessel that optionally may control actuators to move a structure to adjust an effective steering angle of a steerable propulsor.

FIG. 8A illustrates a geometry in which a relatively large interceptor is positioned in the inside of the steering nozzle.

FIG. 8B illustrates that impingement of a large interceptor on the stream at low steering angle may be avoided or reduced by slightly angling the steering nozzle towards the side on which the interceptor is positioned.

DETAILED DESCRIPTION

The inventors have recognized and appreciated that it can be advantageous to increase or otherwise modify the effective steering angle of one or more propulsors of a marine vessel. For example, in some marine vessels the propulsor may be limited in its steering angle due to constraints of the marine vessel or propulsor design. A limited steering angle may limit the ways in which the marine vessel may be controlled. For example, a limited steering angle may render the vessel unable to perform a desired maneuver or certain types of maneuvers. The inability to perform certain maneuvers may inhibit an operator’ s ability to control the marine vessel or respond in a suitable manner.

FIG. 1 shows one example of a way in which the steering angle may be constrained. FIG. 1 shows a diagram of a marine vessel 100 that includes two steerable propulsors 101 and 102, which in this case are waterjets with respective steering nozzles 103 (also known in the art as steering deflectors) and reversing buckets 104 (also known in the art as reversing deflectors) as well as waterjet pump discharge nozzles 105. In this example, the port steerable propulsor 101 has its corresponding reversing bucket 104 (not shown) positioned out of the stream exiting the corresponding steering nozzle 103, which produces a stream 110 in the aft direction at an angle that is the angle of the steering nozzle 103 with respect to the midline 109 of the marine vessel. The starboard steerable propulsor 102 has its corresponding reversing bucket 104 fully lowered to reverse the direction of the stream 111 exiting the corresponding steering nozzle 103. In this example, the reversing buckets 104 reverse the direction of flow from the steering nozzle 103 in a direction that directly opposite to the ahead/astem direction of flow out of the steering nozzle. However, the present disclosure is not limited to these types of reversing buckets, and is also applicable to waterjets with other types of reversing buckets such as so-called “split buckets” or other types of reversing buckets that may reverse the flow at an angle other than 180° with respect to the steering nozzle and/or which may direct the stream into more than one direction.

In the example of FIG. 1 the waterjets are configured in a recessed arrangement, in which the transom 106 of the marine vessel extends significantly behind the pivot point 107 of the steering nozzles 103. The position of the waterjets in such a recessed arrangement constrains the degree to which the steering nozzles 103 can pivot relative to the midline 109 of the marine vessel. This is one example of a way in which the steering angle of a steerable propulsor may be constrained, and the steering angle of a steerable propulsor may be constrained in any of a variety of ways, as the techniques and structures described herein are not limited in this respect.

In the example of FIG. 1, the steering nozzles 103 cannot pivot in excess of 15° relative to the angle of the angle of the midline 109, as physical contact between the propulsors 101, 102 and the transom 106 will occur with any attempt to exceed the 15° limit. The steering angle produced by each steerable propulsor 101, 102 in this example is the same as the angle of a steering nozzle 103 with respect to the midline 109, which in this particular example is limited to 15°.

FIG. 2 shows examples of maneuvers that may not be achievable with steerable propulsors having such a limited steering angle. FIG. 2 shows examples of ways of controlling waterjets to achieve the motions commanded by a combination of a translational movement command for the marine vessel (as exemplified by a joystick position, but not limited thereto) and a rotational movement command for the marine vessel (as exemplified by a helm position, but not limited thereto). Related control techniques are described in U.S. Patent 7,601,040, U.S. Patent 7,037,150, and U.S. Patent 7,222,577, each of which is hereby incorporated by reference in its entirety. However, in the example of FIG. 2, due to the limited steering angle of the waterjets, maneuvers I and J in FIG. 2 may not be capable of being performed, or may be limited, and maneuvers H and K may be marginal or limited, as the steering nozzles 103 cannot move to a sufficiently large angle with respect to the midline to perform such maneuvers. It would be desirable to increase the effective (net) steering angle of the waterjets so that such maneuvers or other maneuvers can be performed. An increase in the deflection of the stream exiting a steerable propulsor relative to the midline 109 corresponds to an increase in the effective steering angle. Deflection of the stream exiting a steerable propulsor relative to the midline 109 may cause an increase in the turning moment or steering effort acting on the vessel by action of the steerable propulsor.

Described herein are structures that can deflect a stream flowing through or behind a steerable propulsor to modify the effective steering angle of a steerable propulsor. For example, in the case of a waterjet, such a structure may impinge upon the stream in a way that changes the angle, relative to the midline of the marine vessel, of at least part of the stream flowing out of the waterjet relative to the angle at which the steering nozzle is positioned. In the case of a steerable propeller, such a structure may impinge upon the stream in a way that changes the angle, relative to the midline of the marine vessel, of at least part of the stream flowing out of the propeller. Examples of structures that can change the steering angle include deflectors and interceptors, but are not limited thereto. An interceptor may be a small surface protruding at an abrupt angle. However, any suitable structure may be used.

FIG. 3A shows a deflector as one example of a structure that can increase the effective steering angle of a steerable propulsor. A deflector may increase the effective steering angle in an inboard or outboard direction. In the example, of FIG. 3A, a deflector 301, 302 may be positioned to increase the outboard steering angle by deflecting the stream expelled from the steering nozzle in an outboard direction, so as to increase the average deflection angle of the stream relative to the midline. In the example of FIG. 3A, deflectors 301 and 302 are positioned to the rear of the steering nozzles 103 and on the outboard side of the steering nozzles 103 to deflect the stream expelled from the steering nozzles in an outboard direction. For example, as shown in FIG. 3A, deflector 301 deflects a portion 310a of the stream exiting the steering nozzle 103 in an outboard direction, thereby increasing the effective steering angle. The deflected portion 310a of the stream may be deflected by the deflector 301 to a larger angle of 45°, for example. If the deflected portion 310a of the stream and the non-deflected portion 310b of the stream 310 are each half of the total stream from the port steering nozzle 103, the result is an effective (or net) steering angle for the steerable propulsor 101 of 30°. However, this is an example, and the techniques described herein are not limited to particular angles.

A deflector may be physically attached to the transom or any other part of the marine vessel, including parts of the marine vessel other than the steering nozzle or transom, such as a bustle or swim platform, or any other structure that overhangs the propulsor, for example. In the example of FIG. 3A, the deflectors 301, 302 are illustrated as being a vane assembly, which may have a “scoop” shape that gradually curves in the outboard direction, as shown in further detail in FIG. 4. However, the present disclosure is not limited to such a design, as the vane assembly may include vanes of any number and any shape that diverts the stream from the steering nozzles in the outboard or inboard direction. Nor is the present disclosure limited to vanes, as the deflector may include any surface or surfaces that diverts the stream from the steering nozzles in an inboard or outboard direction. In the example of FIG. 3A, the steering nozzle is limited to an outboard pivot angle of 15° and the presence of the deflector increases the steering angle to approximately 30° (e.g., by the deflector or interceptor diverting approximately 50% of the stream to an angle of 45°). However, the present disclosure is not limited to particular angles to which the propulsors are constrained or steering angles resulting from the deflection of the stream, as the deflector or interceptor may effectuate any suitable increase of the effective steering angle. The lateral (transverse) placement of the deflector generally will be such to avoid flow impingement when the steering nozzle is in the “straight-ahead” position, however this principle may not always be strictly adhered to, depending upon the application.

Regardless of placement, the deflectors such as deflectors 301, 302 are different from at least some reversing buckets, such as those that deflect flow to the side. The deflectors described herein for modifying the effective steering angle may not reverse the flow to a significant degree or at all. Rather, such a deflector may maintain the direction of the deflected flow of the stream such that it has a fore-aft directional (vector) component in the aft direction, while increasing the effective steering angle. However, in other embodiments a deflector may at least partially reverse the flow.

FIG. 3B illustrates the use of deflectors for the case where the steerable propulsors 101 and 102 are steerable propellers. As with the above-described limitation of waterjets, propellers may also have limitations on their maximum steering angle. Deflectors such as deflectors 301 and 302 may assist in increasing the steering angle, as discussed above. More specifically, the deflectors may deflect the stream from the propellers, and may achieve an effective steering angle beyond that of the angle the propeller forms with respect to the midline.

The structures and techniques described herein are not limited to addressing the situation where the steering angle of a steerable propulsor is limited by a recessed design, and may be used to address any mechanical or other limitation on the steering angle. Additionally, the structures and techniques described herein are not limited for use in situations where the steering angle of the steerable propulsors is limited, and may be used in other designs where there is a desire to increase or otherwise modify the steering angle of steerable propulsor.

Above examples have been described in which a structure is configured to increase the effective steering angle of a steerable propulsor in an outboard direction. In some embodiments, one or more structures may be configured to increase the effective steering angle of a steerable propulsor in an inboard direction. FIG. 3C shows an example in which deflectors 303 and 304 are positioned to the inboard side of their corresponding steerable propulsors 101, 102, respectively, and are configured to divert at least a portion of the stream from the steerable propulsors in an inboard direction (toward the midline 109). For example, when the stream from steerable propulsor 101 is directed in an inboard direction, toward deflector 303, deflector 303 may deflect at least a portion of the stream at an increased angle (in the inboard direction) with respect to the midline 109. Deflector 304 may serve the same function for steerable propulsor 102.

In some embodiments, one or more structures may be configured to increase the effective steering angle of a steerable propulsor in both an inboard and an outboard direction. FIG. 3D shows an example in which deflectors 301 and 302 are positioned on the outboard sides of the steerable propulsors, and are configured increase the effective steering angle of the steerable propulsor in an outboard direction (away from the midline) when at least a portion of the stream from a steerable propulsor is directed into the corresponding deflector. FIG. 3D shows the marine vessel may also include deflectors 303 and 304 positioned to the inboard side of their corresponding steerable propulsors 101, 102, respectively, and are configured to divert at least a portion of the stream from the steerable propulsors in an inboard direction (toward the midline 109) when at least a portion of the stream from a steerable propulsor is directed into the corresponding deflector. Another way to modify the effective steering angle of a propulsor is to use an interceptor. In some embodiments, an interceptor may be integrated with the steering nozzle. One example is shown in FIG. 5A, which illustrates interceptors 501 and 502 inside of the steering nozzle 103 on the inboard side to deflect the stream from the steering nozzle in an outboard direction. An interceptor may be useful in (but not limited to) the case in which the stream from the steering nozzle is narrow relative to the width of the steering nozzle, as this condition allows space for the interceptor without causing flow impingement when the steering nozzle is in the “straight-ahead” position.

In some cases, an interceptor may be positioned on the outboard side of the steering nozzle to deflect the stream from the steering nozzle in an inboard direction, instead of or in addition to positioning an interceptor on the inboard side. FIG. 5B shows an example in which interceptors 503 and 504 are positioned on the outboard side of a steering nozzle 103 to deflect the stream from the steering nozzle in an inboard direction. Positioning the interceptors 503 and 504 as shown in FIG. 5B allows increasing the effective steering angle of a propulsor in an inboard direction, as with the example shown for deflectors in FIG. 3C. FIG. 5C shows an example in which interceptors 501 and 502 are positioned on the inboard side of a steering nozzle to deflect the stream from the steering nozzle in an outboard direction and interceptors 503 and 504 are positioned on the outboard side of a steering nozzle to deflect the stream from the steering nozzle in an inboard direction. Positioning interceptors on both the inboard and outboard sides of a steering nozzle allows increasing the effective steering angle in both an inboard and an outboard direction, as with the example of FIG. 3D. Further, in some embodiments a combination of one or more deflectors and one or more interceptors may be used to modify the steering angle of a propulsor. For example, a steerable propulsor may be provided with both one or more corresponding deflectors 301 (e.g., as illustrated in FIGS. 3A-3D) and one or more corresponding interceptors (e.g., as illustrated in FIG. 5A-5C), in any combination.

FIG. 6 shows another angle illustrating the interceptor 501, according to an example in which the steering nozzle and interceptor have a curved shape. However, the present disclosure is not limited in this respect, as the interceptor 501 may have any suitable shape (e.g., curved in any direction, straight, or another shape) and any suitable size. In some cases, the interceptor 501 may be attached to the steering nozzle (inside or outside, at the back of the steering nozzle, or behind the steering nozzle), and/or may move with the steering nozzle or independently of the steering nozzle. The present disclosure is not limited to diverting the stream behind the steering nozzle, as one or more deflectors or interceptors may be positioned to deflect the stream from the reversing bucket or from the front of a propeller (when actuated with a reversing gear), alternatively or additionally to diverting the stream behind the steering nozzle or steerable propeller.

A deflector or an interceptor, such as deflectors 301-304 and interceptors 501-504, may be fixed in a stationary position or detachable. For example, an interceptor may be fixed to the steering nozzle 103 or detachable from steering nozzle 103. Similarly, a deflector may be fixed to the transom 106 or detachable from the transom 106.

In some embodiments, a deflector or an interceptor may be moveable and/or controllable. For example, a deflector or an interceptor that is controllable may be retractable to be positioned into or out of a stream, or the degree to which the deflector or interceptor extends into the stream may be controlled. The angle of one or more vanes of a deflector or the angle of an interceptor may be controlled (e.g., by an actuator). If a deflector or interceptor is controllable, it may be controlled by a processor or other suitable control circuitry actuating an actuator in response to operator commands, automatically or passively. A deflector or interceptor may include one or more smart materials such as a piezoelectric material, a shape memory alloy, etc. Further, the deflector or interceptor may be positioned such that it is out of the stream of the steering nozzle when the steering angle of the steering nozzle is controlled to be low or zero, or alternatively may be positioned such that it is in the stream of the steering nozzle when the steering angle of the steering nozzle is controlled to be low or zero.

FIG. 7 illustrates a control system 70 for a marine vessel 100 including a processor 71 and a memory 72. The control system 70 may receive vessel control commands such as a steering command, a thrust command and/or a translational movement command from a suitable input device 73, which may include human-operated input devices such as a helm, lever, joystick, etc., computer-operated input devices such as an autonomous control system, or a communication interface that may receive commands from an external or remote location. In response to the vessel control commands, the control system 70 controls the steerable propulsors 101 and 102 using a suitable mapping, such as the mapping shown in FIG. 2, by way of example and not limitation. In the case of waterjets, the control system 70 may control corresponding reversing buckets to be positioned into a stream produced by the steering nozzle to at least partially reverse the direction of flow in response to a thrust command in the astern direction. In some embodiments steerable propulsors 101 and 102 may have one or more associated structures for modifying the steering angle, as discussed above, such as deflectors and/or interceptors, for example. In the case where the structures for modifying the steering angle are controllable, the control system 70 may determine appropriate commands for actuating such structures. For example, in the case of actuators controlling the structures for modifying the steering angle, each such structure may have a corresponding actuator, such as actuator Al and actuator A2 illustrated in FIG. 7, and the processor 71 of control system 70 may send suitable commands to actuators Al and A2 based on information, such as a mapping, stored in the memory 72. In the case where the structures for modifying the steering angle include smart materials, the structures themselves may serve as the actuators. In such a case the actuators Al and A2 shown in FIG. 7 may correspond to the smart materials, and the control system 70 may provide suitable control signals thereto, as discussed above.

It has been recognized and appreciated that a relatively large interceptor may impinge on the stream of the steering nozzle when the steering angle is low or zero. This may create an unwanted effective (net) steering angle and/or limit the ahead thrust that can be produced when the steering angle is low or zero. In some embodiments, the steering nozzle may be turned (e.g., slightly turned) when the steering command for the steerable propulsor is low or zero to move the interceptor out of the stream of the steering nozzle to develop straight ahead thrust or near straight ahead thrust. FIG. 8A illustrates a geometry in which a relatively large interceptor is positioned in the inside of the steering nozzle. When the steering nozzle is positioned at zero degrees deflection, as would typically be done when the commanded steering angle for the marine vessel is zero, the stream flowing through the steering nozzle impinges on the interceptor, which may limit ahead thrust and/or produce an undesirable force vector. FIG. 8B illustrates that this effect may be avoided or reduced by slightly angling the steering nozzle towards the side on which the interceptor is positioned. As long as the stream is narrow enough relative to the steering nozzle opening, the interceptor can thereby be moved out of the flow of the stream at low or zero commanded steering angle for the steerable propulsor. Accordingly, in some embodiments, the control system 70 for the marine vessel may receive a steering command of zero or at a small angle (e.g., below a threshold), and control the steering nozzle to be positioned at a slight angle (e.g., 1-10°) to move the interceptor out of the stream. If the interceptor is positioned on the inboard side of the steering nozzle, the slight angular deflection at zero or low steering angle may be toward the inboard direction. A memory 72 of the control system may store a mapping effecting such control. The particular angle of deflection selected depends on the particular geometry of the steering nozzle, interceptor and stream. This technique may allow an interceptor to be used that would otherwise be too large.

Having described various embodiments, it is to be appreciated that modifications and changes will occur to those skilled in the art and are meant to be encompassed by the scope of the present description.

Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including", "comprising", "having", “containing” or “involving” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

CLAIMS What is claimed is:

1. An apparatus for modifying an effective steering angle of a steerable propulsor of a marine vessel, the apparatus comprising: a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, the structure being configured to be:

A) attached to a steering nozzle of the steerable propulsor; and/or

B) positioned within the stream after the stream has exited the steerable propulsor, wherein the at least a portion of the stream deflected by the structure has a directional component in an aft direction of the marine vessel.

2. The apparatus of claim 1, wherein the structure comprises a deflector or an interceptor.

3. The apparatus of claim 2, wherein the structure comprises a deflector including at least one vane.

4. The apparatus of any preceding claim, wherein the structure is configured to move to change the effective steering angle of the steerable propulsor.

5. The apparatus of any preceding claim, wherein the structure is configured to move in a direction toward or away from the stream.

6. The apparatus of any preceding claim, wherein the structure is configured to be actuated in a direction toward or away from the stream.

7. The apparatus of any preceding claim, wherein the structure is configured to be permanently attached to the marine vessel or detachable.

8. The apparatus of claim 1, wherein the structure is configured to be attached to the steering nozzle.

9. The apparatus of claim 8, wherein the structure is configured to move with the steering nozzle.

10. The apparatus of claim 8 or claim 9, wherein the structure is configured to be attached to an inside of the steering nozzle.

11. The apparatus of any of claims 1-9, wherein the structure is configured to be attached behind the steerable propulsor.

12. The apparatus of any of claims 8-11, wherein the structure comprises an interceptor.

13. The apparatus of claim 12, wherein the interceptor is curved or straight.

14. The apparatus of claim 1, wherein the structure is configured to be positioned within the stream after the stream has exited the steerable propulsor, wherein the at least a portion of the stream deflected by the structure has a directional component in an aft direction of the marine vessel.

15. The apparatus of claim 14, wherein the structure is configured to be attached to a transom of the marine vessel or a steering nozzle of the steerable propulsor. 17

16. The apparatus of claim 15, wherein the structure is configured to be attached to a transom of the marine vessel and comprises at least one vane.

17. The apparatus of claim 1 or any of claims 14-16, wherein the steerable propulsor comprises a steerable propeller.

18. The apparatus of any preceding claim, wherein the structure does not include a reversing deflector.

19. The apparatus of any preceding claim, wherein the structure maintains a forward-aft directional component of the at least a portion of the stream primarily in the aft direction of the marine vessel.

20. A marine vessel comprising the apparatus of any preceding claim and the steerable propulsor.

21. The marine vessel of claim 20, further comprising: a second steerable propulsor; and a second structure configured to deflect at least a portion of a second stream produced by the second steerable propulsor to modify an effective steering angle of the second steerable propulsor, the second structure being configured to be:

C) attached to a steering nozzle of the second steerable propulsor; and/or

D) positioned within the second stream after the second stream has exited the second steerable propulsor, wherein the at least a portion of the second stream deflected by the second structure has a second directional component in the aft direction of the marine vessel. 18

22. A method of controlling the apparatus or marine vessel of any preceding claim.

23. A method for modifying an effective steering angle of a steerable propulsor of a marine vessel, the method comprising: attaching, to the marine vessel, a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, wherein the attaching comprises:

A) attaching the structure to a steering nozzle of the steerable propulsor;

B) attaching the structure to the marine vessel such that the structure is positioned within the stream after the stream has exited the steerable propulsor, wherein the at least a portion of the stream deflected by the structure has a directional component in an aft direction of the marine vessel; or

C) both A) and B).

24. A method for modifying an effective steering angle of a steerable propulsor of a marine vessel, the method comprising: moving a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, wherein the at least a portion of the stream deflected by the structure has a directional component in an aft direction of the marine vessel.

25. A control system for a marine vessel, comprising: a processor configured to receive a steering command for the marine vessel, and, when the steering command commands zero steering angle or a steering angle below a threshold, the processor is configured to control a steering nozzle to angle the steering nozzle such that an interceptor of the steering nozzle is positioned in a direction away from a stream flowing through the steering nozzle. 19

26. The control system of claim 25, wherein when the steering command commands zero steering angle or a steering angle below a threshold, the processor is configured to control the steering nozzle to angle the steering nozzle such that the interceptor is positioned out of a stream flowing through the steering nozzle.

27. The control system of claim 25 or 26, wherein when the steering command commands zero steering angle or a steering angle below a threshold, the processor is configured to control the steering nozzle to angle the steering nozzle at an angle of 1-10° with respect to a midline of the marine vessel.

28. A method of operating a control system of a marine vessel, comprising: receiving, by a processor, a steering command for the marine vessel; and when the steering command commands zero steering angle or a steering angle below a threshold, controlling, by the processor, a steering nozzle to angle the steering nozzle such that an interceptor of the steering nozzle is positioned in a direction away from a stream flowing through the steering nozzle.

29. The method of claim 28, wherein, when the steering command commands zero steering angle or a steering angle below a threshold, the processor controls the steering nozzle to angle the steering nozzle such that the interceptor is positioned out of a stream flowing through the steering nozzle.

30. The method of claim 28 or 29, wherein when the steering command commands zero steering angle or a steering angle below a threshold, the processor controls the steering nozzle to angle the steering nozzle at an angle of 1-10° with respect to a midline of the marine vessel.

31. An apparatus for modifying an effective steering angle of a steerable propulsor of a marine vessel, the apparatus comprising: 20 a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, the structure being configured to be:

A) attached to a steering nozzle of the steerable propulsor; and/or

B) positioned within the stream after the stream has exited the steerable propulsor, wherein the structure does not include a reversing deflector that is configured to be actuated into the stream to produce reverse thrust in response to a marine vessel thrust command in the astern direction.

32. A method for modifying an effective steering angle of a steerable propulsor of a marine vessel, the method comprising: attaching, to the marine vessel, a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, wherein the attaching comprises:

A) attaching the structure to a steering nozzle of the steerable propulsor;

B) attaching the structure to the marine vessel such that the structure is positioned within the stream after the stream has exited the steerable propulsor, wherein the structure does not include a reversing deflector that is configured to be actuated into the stream to produce reverse thrust in response to a marine vessel thrust command in the astern direction; or

C) both A) and B).

33. A method for modifying an effective steering angle of a steerable propulsor of a marine vessel, the method comprising: moving a structure configured to deflect at least a portion of a stream produced by the steerable propulsor to modify the effective steering angle, wherein the structure does not include a reversing deflector that is configured to be actuated into the stream to produce reverse thrust in response to a marine vessel thrust command in the astern direction.