CN115427302A

CN115427302A - Marine drive unit with gyrostabiliser

Info

Publication number: CN115427302A
Application number: CN202180012781.4A
Authority: CN
Inventors: J·B·莫克维奇; M·D·莫克维奇
Original assignee: Halcyon International Pty Ltd
Current assignee: Halcyon International Pty Ltd
Priority date: 2020-02-04
Filing date: 2021-02-04
Publication date: 2022-12-02
Also published as: WO2021155436A1; EP4100316A4; EP4100316A1; AU2021216597A1; JP2023513197A; US20230097909A1

Abstract

The invention provides a marine drive unit (1), such as an outboard motor, for a marine vessel, comprising: an engine or power plant (E), such as an internal combustion engine; a drive transmission for transmitting or transferring the mechanical power generated by said engine or power plant (E) to the propeller shaft for generating propulsion for the vessel; a housing (3) which accommodates or at least partially encloses the motor (E) and/or the drive transmission; a mounting assembly (2) configured to mount the marine drive unit (1) to a hull of a marine vessel, preferably to a stern; and a gyrostabiliser (4) arranged in or on the mounting assembly (2) or the housing (3). As an alternative to an outboard motor, the marine drive unit (1) can be provided as a stern drive unit or as a pod drive unit. The invention also provides a vessel comprising such a drive unit (1).

Description

Marine drive unit with gyrostabiliser

Technical Field

The present invention relates to a marine drive unit with gyrostabiliser, and in particular to a marine outboard motor assembly including a gyrostabiliser.

The marine drive unit of the invention will preferably be in the form of an outboard motor assembly with gyrostabiliser, and it will be convenient to describe the invention in this exemplary context. However, it should be understood that the invention is not limited to this particular embodiment, but may be embodied in other marine drive units, such as stern drive (sternrive) units or pod drive (pod drive) units.

Background

The following discussion of the background in this specification is in no way to be taken as an admission that such background is prior art, or forms part of the common general knowledge in the field in australia or worldwide.

The structure and operation of gyrostabilisers for ships is generally well understood and these devices are increasingly being used in commercial and leisure ships. Gyrostabilisers typically comprise a rotating flywheel mounted in a gimbal frame (gimbal) which allows two of the three possible rotational degrees of freedom, and the frame is rigidly mounted within the vessel. The specific mode that the rotation motion of the flywheel is restricted enables the angular momentum of the autorotation flywheel to be combined with the precession oscillation of the flywheel to generate large torque changing along with time, and the dynamic rolling motion of the ship caused by waves is directly resisted. The rolling motion of the vessel, without any intervention, is combined with the flywheel angular momentum to produce an oscillating precessional motion. This is then combined with angular momentum to produce a steady torque, directly opposing the rolling motion of the vessel caused by the waves. By arranging the universal joints in a specific manner, the naturally occurring physics of gyroscopic dynamics are used to create a roll stabilizer that can operate without further intervention. One example of a marine gyrostabiliser is described in the applicant's co-pending australian patent application no 2017216483A1, the contents of which are incorporated herein in their entirety by direct reference.

In use, gyrostabilisers produce a significant amount of torque, which needs to be transferred into the hull of the vessel. Therefore, a mounting structure for a gyrostabiliser similar to the main motor bracket is usually designed into a vessel. In addition to the rotatably mounted flywheel, the gyrostabiliser unit may also comprise a support frame for its cardan joint bearings, a water pump and a heat exchanger for cooling, a vacuum chamber enclosure (enclosure) for the flywheel and a power supply. In practice, gyrostabilisers may be mounted in a number of positions on the vessel, even off centre. However, since the vertical acceleration level may reduce the life of the main rotation bearing in the gyrostabiliser, it is often preferred to place the gyrostabiliser unit aft of the midship.

Gyrostabiliser units tend to be used only for larger recreational and commercial vessels due to their relatively complex nature, and their associated cost and incorporation into the vessel structure. It is therefore desirable to provide a new gyrostabiliser device that is both suitable and usable for small pleasure craft.

Disclosure of Invention

According to one aspect, the present invention provides a marine drive unit comprising: a mounting assembly for mounting the drive unit to a hull of a vessel, in particular to a beam (transom) at the stern of the vessel, the mounting assembly being configured for substantially rigid connection with the hull, in particular the beam; a drive housing enclosing at least a part of a drive transmission of the drive unit, at least a part of the drive housing being configured to be arranged outboard of the vessel and to be connected to the hull of the vessel, in particular to the transverse beam, by means of the mounting assembly; including a gyrostabiliser in or on the mounting assembly or drive housing.

In this way, the invention can provide a marine drive unit embodied as an outboard motor, stern drive (stern drive) unit or pod (pod) drive unit with gyrostabilisers integrated for use with smaller and other small watercraft. By integrating the gyrostabiliser into the drive unit in this way, the gyrostabiliser can be simplified by removing duplication of the drive unit and other systems or components in the gyrostabiliser unit, such as water pumps, power supplies, housings and support structures, sound attenuation and safety shields. Furthermore, it enables the gyrostabiliser to be mounted on the vessel simply by replacing the outboard motor, or stern drive or pod drive, so that little or no modification is required to the existing vessel.

In a preferred embodiment, the mounting assembly has a generally rigid frame for substantially rigid attachment to the hull, particularly to the transom, but alternatively to the base of the hull. In this regard, the gyrostabiliser may be integrated or incorporated in the mounting assembly such that the shaft of the flywheel of the gyrostabiliser is mounted for rotation relative to and supported by the frame of the mounting assembly, typically by a cardan joint bearing. The substantially rigid frame of the marine drive unit mounting assembly, preferably attached outside the transverse beam, may thus also serve as a support structure for the gyrostabiliser for transferring torque from the gyrostabiliser to the hull of the vessel. Further, the stern on which the outboard motor and the stern drive unit are mounted is generally a region where vertical acceleration is low, and therefore it is most suitable to mount the gyro stabilizer. More specifically, these mounting areas and structures for outboard and stern drives are designed to accommodate the significant forces associated with propelling the watercraft, and are well suited to transferring the gyrostabiliser torque into the hull of the watercraft. The substantially rigid frame of the mounting assembly is configured to be attached to the hull, in particular to the transom, preferably comprising a housing enclosing the gyrostabiliser. The enclosure provided by the mounting assembly may thus provide environmental and safety protection for the gyrostabiliser. Thus, a vacuum chamber that typically (but not always) surrounds a spinning top flywheel may not be required.

In another embodiment, the frame of the mounting assembly of the marine drive unit is configured to be attached or mounted to the hull such that it is at least partially inside the hull; for example, at least partially inside the cross beam (cross). Thus, according to one embodiment, the marine drive unit may have a gyrostabiliser arranged in front of the crossbeam. In the case where the marine drive unit is an outboard motor, the mounting assembly may include a cross-beam bracket, at least a portion of which is configured to be disposed forward of the cross-beam. By combining the gyro stabilizer with the cross member bracket in this manner, the gyro stabilizer can be integrated into the outboard motor assembly so as not to rotate with the motor or transmit a load through the steering bearing of the outboard motor when steering.

In another preferred embodiment, the substantially rigid frame of the mounting assembly may be configured to be substantially rigidly attached to, and preferably pass through, the bottom of the hull. Thus, in this embodiment, the drive unit may be configured as a pod drive unit. In this embodiment, the gyro stabilizer can be easily incorporated to the top, side or rear of the upper gear box of the pod drive unit. As with the stern drive embodiment, the structure supporting the pod drive is both significant and substantially rigid and may be adapted to transfer the forces generated by the gyrostabiliser to the hull with little or no modification.

Accordingly, in a preferred embodiment, the present invention provides a marine drive unit comprising:

a mounting assembly for mounting the drive unit to a hull of a vessel, in particular to a base of the hull, the mounting assembly being configured to be substantially rigidly attached to the hull;

a drive housing enclosing at least a portion of a drive transmission mechanism of the drive unit, at least a portion of the drive housing being configured to be disposed outside of a vessel and connected to a hull of the vessel by the mounting assembly; and

a gyrostabiliser incorporated in or on the mounting assembly and/or the driver housing.

Since, as mentioned above, the structure and operation of a gyrostabiliser for boats is generally very well understood, this description is not intended to provide a detailed description of the basic components of a gyrostabiliser, such as the flywheel, the flywheel shaft, the cardan joint bearings, etc. Rather, this specification guides the reader of skill in the art to other publications to describe or interpret those components.

In a preferred embodiment, the drive housing of the marine drive unit is pivotally connected to the mounting assembly for pivotal movement relative to the hull, in particular relative to the cross-member, about at least one of: a substantially horizontal axis for raising and lowering the drive housing, and a substantially vertical axis for maneuvering the vessel. If the gyrostabiliser is incorporated in the mounting assembly, the drive housing is thus in this embodiment pivotally movable relative to the gyrostabiliser.

In an alternative preferred embodiment, at least a portion of the drive housing is substantially rigid for mounting and supporting thereon at least a portion of the drive transmission mechanism, and the gyrostabiliser is integrated or integrated in the drive housing such that the shaft of the flywheel of the shaft gyrostabiliser is rotatably mounted relative to and supported by the substantially rigid portion of the drive housing, typically in laterally arranged cardan bearings. Thus, in this embodiment, the gyrostabiliser may be integrated or integrated (i.e. mounted and supported) in and/or on the drive housing, as opposed to the mounting assembly. In this way, the outboard drive housing may serve as a support structure for the gyrostabiliser and also for transferring torque from the gyrostabiliser to the hull through its connection to a mounting assembly designed to be rigidly attached to the hull, in particular a transom. The drive housing preferably substantially encloses the gyrostabiliser. The enclosure of the drive housing may thus provide environmental and safety protection for the gyrostabiliser. Thus, a vacuum chamber that typically (but not always) encloses the spinning top flywheel may not be required.

As mentioned above, in the case of outboard motors or stern drive units, the drive housing is typically pivotally connected to the mounting assembly for pivotal movement relative to the hull, and in particular relative to the transom, about at least one of: a substantially horizontal axis for raising and lowering the drive housing, and a substantially vertical axis for maneuvering the vessel. Thus, in embodiments in which the gyrostabiliser is integrated or incorporated in the drive housing, the gyrostabiliser may be arranged to be pivotally movable with the drive housing relative to the mounting assembly. However, it is important that pivoting of the drive housing about a horizontal axis (i.e. raising or lowering the drive housing) does not normally occur during driving. Although the pivoting motion of the gyrostabiliser about a substantially vertical axis (i.e. during steering) may cause some disturbance or perturbation to the stabilising effect of the flywheel (which may also rotate about a vertical axis), it is envisaged that any such disturbance or perturbation will be minimal as the degree or extent of such turning motion will generally only be significant at low speeds and in regions which are generally very hidden, for example. In ports or docks.

In a preferred embodiment, the drive housing may enclose substantially the entire drive transmission of the drive unit, and preferably also the engine or motor powering the drive transmission. In this regard, the marine drive unit may preferably be provided in the form of an outboard motor. In embodiments where the gyrostabiliser is integrated or incorporated in the drive housing-for example, the shaft of the gyrostabiliser's flywheel is rotatably mounted relative to and supported by a substantially rigid portion of the drive housing, typically in a gimbaled bearing-two main positions are contemplated for positioning the gyrostabiliser; i.e., (i) on a front side or region of the drive housing, desirably above the mounting assembly, and (ii) on a rear side or region of the drive housing, desirably near the level or height of the mounting assembly. By integrating the gyrostabiliser into the outboard motor according to the invention, it is possible to eliminate a separate heat exchanger for the gyrostabiliser by using an outboard seawater cooling system. In addition, the engine sound damping device can also be used for a gyrostabiliser.

In at least one embodiment, the invention therefore provides a marine drive unit, such as an outboard motor for a marine vessel, comprising: an engine or power plant, such as an internal combustion engine; a driving transmission mechanism for transmitting or transmitting the mechanical power generated by the engine or the power device to the propeller shaft, namely generating propulsion for the ship; a housing that houses or at least partially encloses the engine and/or drive transmission; a mounting assembly configured to mount the outboard motor to a hull of the marine vessel, such as a beam; and a gyrostabiliser disposed in or on the mounting assembly or housing. It should be noted that the engine or power plant of the marine drive unit may comprise a two-stroke, four-stroke or diesel internal combustion engine, or it may also comprise one or more electric motors.

In one embodiment, the mounting assembly of the outboard motor comprises a substantially rigid mounting bracket configured to be secured to a transom of the marine vessel, the gyrostabiliser being disposed in or on the mounting assembly, for example by means of releasable clamping bolts, such that the shaft of the flywheel of the gyrostabiliser is rotatably mounted and/or supported on the rigid mounting bracket. In this regard, the mounting assembly will typically include a housing that surrounds the gyrostabiliser.

In another embodiment, at least part of the housing of the outboard motor is substantially rigid to mount and support the drive transmission mechanism therein and/or thereon, and the gyrostabiliser is arranged within the housing such that the shaft of the flywheel of the gyrostabiliser is rotatably mounted and/or supported within or on the substantially rigid part of the housing.

In another preferred embodiment, the marine drive unit is provided in the form of a stern drive unit.

In another preferred embodiment, as already indicated, the marine drive unit may be configured as a pod drive unit.

According to a further aspect, the invention provides a marine vessel (marine vessel), in particular a boat (boat), comprising or incorporating a marine drive unit according to the invention according to any of the embodiments described above.

With the marine drive unit according to the invention, the main supporting frame of the gyrostabiliser, such as the engine block or cylinder head, the main gearbox, the lower leg box or mounting flange and the bracket, can be removed by integrating the gyrostabiliser into the structural frame elements of the outboard, stern drive or pod drive unit. Furthermore, since the present invention requires little or no modification to existing boat or vessel structures, the gyrostabiliser can be installed in the vessel simply by replacing the outboard motor or stern drive or pod drive. This creates a retrofit market for gyrostabilisers and opens up a new alternative market for outboard motors, stern drive units and pod drive units.

Drawings

For a more complete understanding of the present invention and the advantages thereof, exemplary embodiments of the present invention are explained in more detail in the following description with reference to the accompanying drawings, wherein like reference numbers represent like parts, and wherein:

fig. 1 is a schematic side view of a marine outboard motor showing three possible positions a, B, C of an integrated gyrostabiliser according to an embodiment of the invention;

fig. 2 is a schematic rear perspective view of the outboard motor for a ship, showing three positions of the gyrostabiliser shown in fig. 1.

Fig. 3 is a schematic front perspective view of the outboard motor for a ship, showing three positions of the gyrostabiliser shown in fig. 1. And

fig. 4 is a schematic side view of a pod drive unit for a ship according to an embodiment of the invention.

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate specific embodiments of the invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the attendant advantages will be readily appreciated as they become better understood by reference to the following detailed description.

It should be appreciated that common and/or well-understood elements that may be useful or necessary in a commercially feasible embodiment are not necessarily depicted to facilitate a more abstract view of the embodiment. The elements of the drawings are not necessarily to scale relative to each other. It will also be appreciated that certain actions and/or steps in embodiments of the methods may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.

Detailed Description

Referring to fig. 1 to 3 of the drawings, a marine drive unit 1 according to the invention is embodied as an outboard motor and is shown in three views. Each of these figures illustrates an alternative embodiment of the marine drive unit 1.

The marine drive unit or outboard motor 1 includes a mounting assembly 2 for mounting the outboard motor 1 to a transom (not shown) of a stern of a marine vessel (not shown) and a drive case 3 surrounding an engine and a transmission mechanism of the outboard motor 1. The gyrostabiliser 4 is shown integrated in the outboard motor 1 in three different possible positions a, B, C, and each of these positions a, B, C represents an alternative embodiment of the marine drive unit or outboard motor 1.

First, considering the integration of gyrostabiliser 4 into outboard motor 1 at position a, it will be appreciated that gyrostabiliser 4 is incorporated in a mounting assembly 2, which mounting assembly 2 is configured to be substantially rigidly attached to a transom of a marine vessel. In this regard, the mounting assembly 2 comprises a substantially rigid frame 5 (e.g. made of steel), the frame 5 comprising a bracket 6, the bracket 6 being securely fastened or attached to the transom of the vessel by means of a fastener such as a bolt, in particular a releasable threaded clamping bolt, as is known in the art. As shown in fig. 1, the gyrostabiliser 4 is mounted and supported on the rigid frame 5 of the mounting assembly 2 in a position outside the vessel and at the rear of the bracket 6, between the bracket 6 and the drive housing 3 of the outboard motor. In this regard, the gyrostabiliser 4 is enclosed within a housing 7 on a rigid frame 5 of the mounting assembly 2 such that the shaft S of the flywheel F of the gyrostabiliser 4 is rotatably mounted relative to the frame 5 and supported by the frame 5 by means of laterally arranged cardan bearings (not shown). The housing 7, integral to the rigid frame 5 of the mounting assembly 2, provides both environmental protection for the gyrostabiliser 4 and safety and noise dampening for the vessel user during operation of the gyrostabiliser 4. The position of the casing 7 on the frame fig. 5 also enables the gyrostabiliser 4 to utilise the water pump and the power supply of the outboard motor 1 during operation.

The drive housing 3 of the outboard motor 1 encloses an engine (not shown) under an upper cowl or cover 8 of the housing 3, referred to as the power head of the outboard motor 1, and the drive shafts (not shown) of the gearbox and drive transmission within the middle portion 9 and lower portion or base 9' of the housing 3 (i.e., under the power head), which then transmit or transfer power through the drive shafts to the propellers or propellers of the outboard motor 1. The drive housing 3 is pivotally connected to the mounting assembly 2 at a hinge or pivot joint 10 for pivotal movement relative to the cross-beam about a substantially horizontal axis X for raising and lowering the drive housing 3. The drive housing 3 is also pivotally connected to the mounting assembly 2 for pivotal movement relative to the cross beam about a substantially vertical axis Y for steering the vessel, and which axis is substantially aligned with the axis of rotation Y of the flywheel shaft S of the gyrostabiliser 4. Thus, in this embodiment, the drive housing 3 is configured to be pivotally movable relative to the gyro stabilizer 4 at the position a about the axes X, Y.

Secondly, considering the embodiment in which the gyrostabiliser 4 is integrated into the drive unit or outboard motor 1 at position B, it can be seen that in this case the gyrostabiliser 4 is incorporated into a drive housing 3, at least a portion of which drive housing 3 (under an upper cover or bonnet 8 providing access to the engine) is substantially rigid (e.g. made of steel) for mounting and supporting the engine and drive mechanism therein. In this position B, gyrostabiliser 4 is thus engaged (i.e. mounted and supported) at a front side or region of drive housing 3 within drive housing 3 above mounting assembly 2, rather than in or on mounting assembly 2. In this way, the drive housing 3 can serve both as a housing for the gyrostabiliser 4, i.e. to protect the gyrostabiliser 4 from sea water and the environment, and as a support structure for the gyrostabiliser 4, i.e. to transmit torque from the gyrostabiliser 4 to the hull via its connection to the mounting assembly 2, which mounting assembly 2 in turn is substantially rigidly attached to a beam (not shown).

As mentioned above, the drive housing 3 is here pivotally connected to the mounting assembly 2 for pivotal movement relative to the transverse beam about each of the substantially horizontal axes X to raise and lower the drive housing, and about each of the substantially vertical axes Y to steer the vessel. Thus, in this embodiment, the gyrostabiliser 4 is pivotally movable with the drive housing 3 relative to the mounting assembly 2. However, pivoting the drive housing 3 about the horizontal axis X to raise or lower the drive housing 3 does not generally occur during driving. Although steering movement of the gyrostabiliser 4 about the substantially vertical axis Y may cause some disturbance or perturbation to the stabilising effect of the flywheel F (which rotates about the substantially vertical axis Y'), it is envisaged that any such disturbance or perturbation will be minimal as the degree or extent of steering movement about the Y axis will generally only be significant at low speeds of manoeuvring and in generally very concealed areas, for example in ports or docks. By incorporating the gyrostabiliser 4 within the drive housing 3, this housing 3, already providing safety and environmental protection and sound attenuation for the engine and transmission of the drive unit 1, can then be used for the gyrostabiliser 4. Again, the gyro stabilizer 4 of the present embodiment can also utilize the water pump and the power supply of the outboard motor 1 during operation.

Thirdly, considering the integration of the gyrostabiliser 4 into the outboard motor 1 at position C, it can be seen that in this case the gyrostabiliser 4 is incorporated into the drive housing 3 at about the level or height of the mounting assembly 2 at the rear or rear region. In position C, the drive housing 3 again serves as a housing and support structure for the gyrostabiliser 4 for transmitting torque from the gyrostabiliser 4 (which rotates about the substantially vertical axis Y ") through its connection to the mounting assembly 2 to the hull of the vessel, while the mounting assembly 2 is in turn substantially rigidly attached to the cross-beam. In this regard, the gyrostabiliser 4 may be supported in the housing 3 with the shaft S of the flywheel F rotatably mounted in laterally arranged cardan bearings (not shown). The outboard motor 1 of the present invention will preferably have a higher power rating, such as 50Hp and above (e.g., 100-500 Hp), although smaller outboard motors 1 with power below 50Hp are technically feasible, but may be less commercially feasible.

Referring now to fig. 4 of the drawings, the marine drive unit 1 is shown in the form of a pod (pod) drive unit. The pod drive unit 1 comprises a mounting assembly 2 for securely mounting the pod drive unit 1 to the bottom of the hull H of a marine vessel in a manner known in the art. The pod drive unit 1 further comprises a drive housing 3, which drive housing 3 interconnects an output shaft (not shown) of an engine or power plant E of the pod drive unit 1 with a gear box and drive train (drive train) or drive transmission within the intermediate portion 9 and a lower portion 9 'of the housing 3, and which lower portion 9' incorporates a propeller or propeller P on a propeller shaft mounted outside the hull H. In this embodiment, a gyrostabiliser 4 comprising a flywheel F rotatably mounted on a shaft S for high speed rotation about an axis Y is integrated on the drive housing 3 of the pod drive 1 enclosed within its own housing 7, such that the shaft S of the flywheel F is rotatably mounted and supported on the housing 3 relative to the housing 7 by a cardan joint bearing (not shown). Furthermore, the rigid structure of the drive housing 3, in particular the intermediate portion 9, is firmly fixed to the hull H for transmitting the stabilizing forces generated by the gyrostabiliser to the hull H. As previously described, the arrangement in this embodiment can eliminate duplication of systems or components present in the pod drive unit 1 and the gyrostabiliser, such as water pumps, power supplies, housings, support structures, sound attenuation and safety enclosures. A similar arrangement may be applied to embodiments of the stern drive unit according to the invention. Also, for pod drive and stern drive units, power ratings above 50Hp are preferred.

Although specific embodiments of the invention have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations exist. It should be appreciated that each of the exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. In general, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "contains," "containing," "has," "having" and any variations thereof, unless the context requires otherwise, all documents are intended to be interpreted in an inclusive (i.e., non-exclusive) manner such that a process, method, apparatus, device, or system described herein is not limited to those features, integers, portions, elements, or steps, but may include other features, integers, portions, elements, or steps not expressly listed and/or inherent to such process, method, apparatus, device, or system. Furthermore, the terms "a" and "an," as used herein, are intended to be construed as one or more, unless explicitly stated otherwise. Furthermore, the terms "first," "second," "third," and the like are used merely as labels, and are not intended to impose numerical requirements on their objects or to establish a certain level of importance. Furthermore, positional terms used in the above description, such as "lower" and "upper," should be understood in the context of the embodiments described in the drawings, and should not be construed as limiting the invention to the literal interpretation of the terms, but as understood by those skilled in the art in appropriate context.

Claims

1. A marine drive unit comprising:

a mounting assembly for mounting the drive unit to a hull of a vessel, in particular to a beam at the stern of a vessel, the mounting assembly being configured to be substantially rigidly attached to the hull, and in particular to the beam;

a drive housing enclosing at least a part of the drive transmission of the drive unit, the drive housing being configured to be arranged outside the vessel and to be connected to the hull of the vessel, in particular a beam, by means of the mounting assembly; and

a gyrostabiliser contained within one of the mounting assembly and the drive housing.

2. The marine drive unit of claim 1 wherein the mounting assembly has a substantially rigid frame for substantially rigid attachment to the hull, in particular the transom, and wherein the gyrostabiliser is incorporated in the mounting assembly such that the shaft of the gyrostabiliser's flywheel is rotatably mounted relative to and supported by the frame of the mounting assembly.

3. The marine drive unit of claim 2 wherein the substantially rigid frame of the mounting assembly includes a housing surrounding the gyrostabiliser.

4. The marine drive unit according to any one of claims 1-3, wherein the drive housing is pivotally connected to the mounting assembly for pivotal movement relative to the hull, in particular the transverse beam, about at least one of a substantially horizontal axis for raising and lowering the drive housing, and a substantially vertical axis for operating the vessel, wherein the drive housing is pivotally movable relative to the gyrostabiliser.

5. The marine drive unit of claim 1 wherein at least a portion of the drive housing is substantially rigid for mounting and supporting the at least a portion of the drive transmission thereon, and wherein the gyrostabiliser is incorporated in the drive housing such that a rotating portion of a flywheel of the axle gyrostabiliser is rotatably mounted relative to and supported by the substantially rigid portion of the drive housing.

6. The marine drive unit of claim 5 wherein the drive housing substantially surrounds the gyrostabiliser.

7. The marine drive unit of claim 5 or 6 wherein the drive housing is pivotally connected to the mounting assembly for pivotal movement relative to the hull, in particular the transom, about at least one of a substantially horizontal axis for raising and lowering the drive housing and a substantially vertical axis for operating the vessel, wherein the gyrostabiliser is pivotally movable with the drive housing relative to the mounting assembly.

8. The marine drive unit according to any one of claims 1 to 7, wherein the drive housing encloses substantially the entire drive transmission of the drive unit, and preferably also an engine or motor powering the drive transmission.

9. The marine drive unit of claim 8 wherein the marine drive unit is in the form of an outboard motor.

10. The marine drive unit of any one of claims 1 to 7 wherein the marine drive unit is in the form of a stern drive unit.

11. The marine drive unit of any of claims 1-7, wherein the marine drive unit is in the form of a pod drive unit.

12. An outboard motor for a marine vessel, the outboard motor comprising:

an engine or power plant, preferably an internal combustion engine;

a drive transmission mechanism for transmitting the mechanical power generated by the engine or the power device to a propeller shaft;

a housing that houses or at least partially encloses the engine and/or the drive transmission;

a mounting assembly configured to mount the outboard motor to a hull of a marine vessel, particularly a stern; and

a gyrostabiliser disposed in or on the mounting assembly or housing.

13. The outboard motor of claim 12, wherein the mounting assembly includes a substantially rigid mounting bracket configured to be secured to a transom of the marine vessel, and the gyrostabiliser is arranged in or on the mounting assembly such that a shaft of a flywheel of the gyrostabiliser is rotatably mounted and/or supported on the rigid mounting bracket.

14. The marine drive unit of claim 13 wherein the mounting assembly has a housing that surrounds the gyrostabiliser.

15. The marine drive unit of claim 12 wherein at least a portion of the housing is substantially rigid for mounting and supporting the drive transmission therein, and wherein the gyrostabiliser is arranged in the housing such that the shaft of the gyrostabiliser's flywheel is rotationally mounted and supported in or on the substantially rigid portion of the housing.

16. A marine vessel, in particular a ship, comprising a marine drive unit according to any of the preceding claims.