AU776164B2 - Buoyant stabilizer unit - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Name of applicant: Actual Inventors: Address for service: Invention Title: Michael Hebden Bennett Michael Hebden Bennett M. J. SERVICE ASSOCIATES Ellinghaus Linder PO Box 123 Carlton South VICTORIA 3053 BUOYANT STABILIZER UNIT The following statement is a full description of this invention, including the best method of performing it known to us: BUOYANT STABILIZER UNIT TECHNICAL FIELD The present invention relates to a buoyant stabilizer unit for attaching to a boat for providing lateral stability.

BACKGROUND ART Conventional buoyant stabilizers for providing lateral stability to a boat are in the form of, for example, floating outriggers which are positioned to one or both sides of a boat hull.

Such floating outriggers provide considerable stability, however, there are disadvantages in that the boat width is significantly increased, making handling both in and out of water difficult, and the outrigger can add significantly to drag. Moreover, due to the configuration with an outrigger, it is generally impracticable to also use an outrigger for mounting an external motor.

Another form of a buoyant stabilizer is in the form of an inflatable gunwale.

However this inflatable gunwale is located above the water line of the boat and is designed for providing stability and flotation only in emergency situations such as if the boat is swamped or leaks. Moreover such an inflatable gunwale cannot be easily *adapted for use in stowing equipment.

U.S. Pat. No. 5,322,030 0 to Brehmer describes a buoyant stabilizer in the form S 20 ofa floating transom extension assembly for adjustably positioning an outboard motor upon a boat. This assembly is designed for attachment directly onto the transom of a power boat, and in one aspect is aimed at providing longitudinal stability for situations S* •where an operator needs to stand near the stern of the boat, for example when checking for mechanical failure. The assembly described is relatively narrow compared to the width of the boat with which it is used, and is designed for mounting at the center line of the boat, and thus provides no lateral stability.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a buoyant stablizer unit which addresses the aforementioned shortcomings of the abovementioned buoyant stablizers, or which at least provides the public with a useful choice.

According to a first aspect of the present invention there is provided a buoyant stablizer unit comprising: a flotation member with an external surface portion adapted for abutting against a side surface of a boat hull at a location below a waterline of the boat hull and formed in a streamlined shape to minimize drag when abutted against the boat hull with the boat moving forward, the flotation member having a portion extending beyond the stem of the boat hull; and an attachment device for attaching the unit to the boat hull.

With such a construction, a boat can be stabilized by attaching one such unit to each side of the boat hull. Moreover, since the unit is abutted against the side surface of the hull below the water line and is formed in a streamline shape additional drag can be kept to a minimum. Furthermore, with this aspect of the invention an additional feature is that since the flotation members are attached to either side of the hull, the unit can be used with a conventional power boat with an inboard or outboard motor, without interfering for example with the mounting of the motor at the stem region.

The attachment device may comprise any suitable device whereby the unit can be attached to the boat with which it is to be used.

For example in the case of a unit attached directly to each side of a boat, the attachment device may comprise one or more fasteners for connecting between each unit and a structure of the hull.

The construction may be such that there is further provided a motor mounting device for mounting a motor on the unit, for propulsion thereof.

With such a construction, a boat with which the unit is used, can be propelled by 0000 a motor mounted on the buoyant stabilizer unit. Such an arrangement may be suitable for craft which do not have a facility for mounting a motor such as kayaks and canoes, or for situations where it is desired to mount an extra or larger motor.

The motor mounting device may be designed for mounting an internal motor within or on the unit, or an outboard motor.

3 The construction may be such that the unit further comprises a stowage compartment provided in the flotation member.

By providing a stowage compartment, the versatility of the unit is further increased.

According to a second aspect of the present invention there is provided a buoyant stabilizer unit wherein two of the flotation members according to the first aspect are provided, and there is further provided: a base member adapted for connection between the two flotation members so as to provide a sufficient mutual spacing to accommodate the stern region of a boat with which the unit is to be used.

With such a construction, the two flotation members can be connected together by the base member to provide a single unit which can be easily fitted to the stern region of a boat. Moreover, the base member provides rigidity to the unit, and simplifies attachment to the boat. Furthermore, the base member may be designed to match with the bottom of the boat hull to increase the water line length and improve performance of the boat under power.

Moreover, the aforementioned motor mounting device may be provided on the base member, thus providing a central motor mounting facility.

With such a construction an external motor such as an outboard motor or a motor mounted within the unit, can be safely used with narrow craft such as canoes and 20 kayaks.

"In the case where the unit is to be used with a canoe or kayak, then preferably the space between the flotation members is formed in a deep U-shape for accommodating the stern region of the canoe or kayak.

S"The flotation members may comprise any suitable material or construction whereby flotation can be provided. For example the flotation members may comprise inflatable flotation members. Alternatively these may comprise foam flotation members. Moreover, these may comprise hollow shell flotation members.

Any suitable device may be provided for connecting the flotation members together by means of the base member. For example this may involve forming suitable 4 mating surface on the flotation members and the base member, and securing the flotation members to the base member by interlocking the mating surfaces and or using attachments such as bolts or straps.

Alternatively the flotation members may be formed integral with the base member. By forming the flotation members integral with the base member, the unit can be made as a single unit, with increased rigidity and possible savings in cost. Moreover, the spacing between the flotation members can be reliably ensured. Hence the unit can be especially designed for craft such as canoes and kayaks of a predetermined size and shape, so as to enable secure attachment thereto.

In the case of an integral construction, the unit may be molded as an integral hollow plastics structure. Ideally such a structure may be formed by conventional molding techniques such as rotational molding, enabling reliable construction with further reduction in cost.

The attachment device may comprise any suitable device whereby the unit can be attached to the boat with which it is to be used, with the stern region of the boat positioned between the flotation members.

For example, this may comprise sockets or lugs for attachment of linking members between the stem region of the boat and the unit.

Furthermore this may comprise a surface of the unit suitably reinforced for 20 enabling the transfer of loads between the unit and the stern region of the boat.

Moreover, this may comprise mating sections formed on the unit for mating with a surface of the boat to secure or assist in securing the boat to the unit.

Furthermore, this may comprise a device such as an inflatable bladder positioned on the inside surfaces of the flotation members and adapted for gripping against opposite sides of the stern of a boat when inflated. Moreover, in the case where the flotation members are inflatable, the flotation members may constitute the inflatable bladder.

The motor mounting device may comprise any suitable device whereby a motor for propulsion can be mounted on the unit. For example this may comprise a motor mounting device adapted for mounting one or more outboard motors, and/or a motor mounting device adapted for mounting one or more motors for propulsion of the unit within the unit.

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a first embodiment of a buoyant stabilizer unit according to the invention, being an overall perspective view of the unit attached to a boat, being a half section view on A-A, and being a half rear view.

FIG. 2 is a schematic diagram illustrating a second embodiment of a buoyant stabilizer unit according to the invention, with two flotation members connected together to form an integral unit, being an overall perspective view of the unit attached to a boat, and being a rear view.

FIG. 3 is a side view of a similar unit to that of FIG. 2 with an outboard motor mounted thereon.

FIG. 4 is a schematic diagram showing a plan view of a third embodiment of a buoyant stabilizer unit according to the invention, illustrating an inflatable attachment device.

FIG. 5 is a schematic diagram showing a plan view of a fourth embodiment of a buoyant stabilizer unit according to the invention specially adapted for use with a kayak.

FIG. 6 is a sectional view on A-A of FIG. 5, illustrating aspects of a boat attachment unit.

FIG. 7 is a sectional view on B-B of FIG. 5, illustrating top attachment details.

FIG. 8 is a sectional view on B-B of FIG. 5, illustrating bottom attachment FIG. 8 is a sectional view on B-B of FIG. 5, illustrating bottom attachment details.

6 BEST MODES FOR CARRYING OUT THE INVENTION FIG. 1 is a schematic diagram illustrating a first embodiment of a buoyant stabilizer unit 1 according to the invention, being an overall perspective view of the unit 1 attached to a boat 2, being a half section view on A-A, and being a half rear view. As shown in FIG. 1 two buoyant stablizer units 1 according to the invention are attached to either side of a hull 3 of the boat 2. Each of the stabilizer units I comprises: a flotation member 4 with an external surface portion 5 (see FIG. 1(B)) adapted for abutting against a side surface 6 of the boat hull 3 at a location below a waterline 7 of the boat hull 3 and formed in a streamlined shape to minimize drag when abutted against the boat hull 3 with the boat 2 moving forward; and an attachment device in the form of bolts 8 (see FIG. through the side of the boat hull 3, for attaching the unit 1 to the boat hull 3.

With such a construction the boat 2 is stabilized by attaching one unit 1 to each side of the boat hull 3. Moreover, since each unit 1 is abutted against the side surface 6 of the hull 3 below the water line 7 and is formed in a streamline shape, additional drag can be kept to a minimum.

As shown in FIG. 1, the flotation members 4 each comprise a stowage compartment 9 for stowing equipment. Also each of the stowage compartments 9 is designed with a motor mounting region 10 so that an outboard motor (not shown) can 20 be mounted on the stern 11 of the flotation member 4 if desired.

In FIG. 1 the space between the units 1 is sufficient to allow an outboard motor to be mounted to a transom 12 of the boat hull 3 in the conventional manner.

FIG. 2 is a schematic diagram illustrating a second embodiment of a buoyant stabilizer unit 20 according to the invention, with two of the flotation members 4 of the first embodiment of FIG. 1 connected together to form an integral unit 20. FIG. 2 is an overall perspective view of the unit 20 attached to a boat 21, and FIG. 2 is a rear view. In FIG. 2, components having a similar function to those in FIG. 1 are denoted by S" the same reference symbols.

7 In this embodiment the two flotation members 4 of FIG. 1 are connected together by a base member 22 so as to provide a sufficient mutual spacing to accommodate the stem region of the boat 21 with which the unit 20 is to be used.

With such a construction, the single buoyant stabilizer unit 20 comprising the two flotation members 4 and the base member 22 can be easily fitted to the stern region of the boat 21. Moreover, the base member 22 provides rigidity to the unit 20, and facilitates attachment to the boat 21. For example depending on the design of the flotation members 4, the unit 20 may be detachably attached by means of the base member 22, rather than by using the fastener attachment method using the bolts 8 as shown in FIG. 1.

The base member 22 may be made of a different material to the flotation members 4 and permanently or detachably attached thereto by fasteners. For example the base member 22 may be fabricated from aluminium sheet with the flotation members 4 made of plastics by rotational molding. Alternatively the base member 22 and the flotation members 4 may be formed as an integral unit by rotational molding to give an integral stabilizer unit FIG. 3 is a side view of a similar unit to that of FIG. 2 with an outboard motor 23 mounted on the base member 22. As is more apparent in FIG. 3, the bottom of the base member 22 and the rear end of the flotation members 4 are designed to match with :0•%20 the bottom of the hull 24 to increase the water line length and improve performance of the boat 21 under power.

FIG. 4 shows a plan view of a third embodiment of a buoyant stabilizer unit according to the invention generally indicated by arrow 30, illustrating an inflatable attachment device. In FIG. 4, only the stem region 31 of a boat 32 with which the unit 25 30 is to be used is shown. As shown in the figure, the unit 30 comprises a base member Poo*generally indicated by arrow 33. With this embodiment, for illustration only, the base member 33 is in the form of a channel section with a rear flange 34 of the channel -o constituting an attachment bracket for attaching an outboard motor 35 serving as an external motor for propulsion. Two elongate flotation members 36 and 37 are connected together by the base member 33 by means of attachment bolts 38 onto rear attachment sections, so as to extend from the base member 33 at a sufficient mutual 8 spacing to accommodate the stem region 31 of the boat 32. An attachment unit for attaching the unit 30 to the stem region 31 of the boat 32, with the stem region 31 of the boat 32 positioned between the flotation members 36 and 37, involves plate members 39 and 40 which are bolted between forward attachment sections of the flotation members 36 and 37 and gunwales 41 and 42 of the boat 32 on the port and starboard sides, by bolts 43 and 44 respectively. With this embodiment, the flotation members 36 and 37 comprise rigid members for the aforementioned attachment sections, and inflatable pontoons 45 and 46 bonded thereto. After attachment of the unit 30 to the stem region 31 with the pontoons 45 and 46 partially inflated, the pontoons 45 and 46 are further inflated against the sides of the stem region 3 1, thereby providing a more secure attachment.

With such a construction the outboard motor 35 can be attached to the stem region 31 of the boat 32, for propulsion of the boat 32. Moreover, the flotation members 36 and 37 support the weight of the outboard motor 35 and also provide lateral stability. Hence a larger outboard motor can be safely used. Furthermore, the stability provided by the flotation members 36 and 37 enables outboard motors to be safely used with slender boats such as canoes or kayaks having limited stability.

S. An altemrnative conceptual arrangement for when the external motor for propulsion of the unit is mounted within the unit 30, is illustrated by the dotted lines in 20 FIG. 4. In this case the motor mounting device is constituted by motor mounts 47 secured to the structure of the flotation members 36 and 37, and motors 48 are mounted thereon, with propeller shafts 49 taken out through the respective rear walls 50 of the S'°units 30. Of course in this case the inflatable pontoons 45 and 46 would be suitably designed to provide secure attachment to the stem region 31, while enabling a rigid 25 structure to be provided for the motor mounts 47 and the rear walls 50 of the unit Alternatively, the inflatable pontoons 45 and 46 may be replaced with rigid pontoons.

S "Of course other arrangements for propulsion motors are possible. For example only one propulsion motor in one of the flotation members 36, 37 may be sufficient, or a motor mounting device for a single propulsion motor may be provided centrally within a central casing provided between the flotation members 36, 37. Moreover, motor mounting devices for two outboard motors may be provided at the rear of each flotation member 36, 37, or combinations of these is also possible.

9 A fourth embodiment of the invention will now be described with reference to FIG. 5 through FIG. 8. The buoyant stabilizer unit according to the fourth embodiment, generally indicated by arrow 60 is formed as an integral hollow plastics structure, made by rotational molding, using conventional rotational molding plastics materials such as polyethylene Here two flotation members 61 and 62 are formed integral with a base member generally indicated by arrow 63 as a hollow shell structure. The base member 63 is adapted for attachment to an outboard motor 64 by forming a well region 65 with a rigid back wall 66 to which the outboard motor 64 can be attached by standard clamp screws 67.

This embodiment is designed for use with a standard size kayak generally indicate by arrow 68. Hence in this case the attachment device for attaching to the kayak 68 with a stem region 69 of the kayak 68 positioned between the flotation members 61 and 62, comprises mating sections 70 and 71 (FIG. 6) formed on the left and right flotation members 61 and 62 of the unit 60, for mating with an outer surface 72 of the hull of the kayak 68 to secure or assist in securing the kayak 68 to the unit Moreover, as shown in FIG. 5, and in detail in FIG. 7 and FIG. 8, the attachment device includes an upper tang 73 for connecting to the top end face of the stem region 69, and two lower tangs 74 and 75 for connecting to the bottom of the stern region 69. The tangs 73, 74 and 75 are each formed from stainless steel plate strip with several mold 20 securing holes formed in the base end, and an attachment hole formed in the forward end. The tangs 73, 74 and 75 are molded into the unit 60 at the time of molding the unit with the area around the tangs 73, 74 and 75 being suitably reinforced for enabling the transfer of loads between the unit 60 and the stern region 69 of the kayak 68.

The stem region 69 is formed with encapsulated nuts 76 at the time of molding.

Alternatively nut inserts may be fitted to an already molded hull.

Stainless attachment bolts 77 each with a folding ring 78 pivotally connected to the head, are used to connect the tangs 73, 74 and 75 to the stern region 69, by inserting S"the bolts 77 through the attachment holes and tightening into the nuts 76. Once secured, the rings 78 are folded flat out of the way.

As shown in FIG. 5, the unit 60 also includes stowage wells 79 on the port and starboard side for stowing equipment such as fuel tanks, batteries, fishing or expedition equipment and the like. Racks 80 are also provided on the deck of the unit 60 for holding items such as paddles and fishing rods. Moreover, hatches 81 are provided in the deck forward of the wells 79 for access to the interior of the unit 60, for stowing other equipment in a water tight condition.

Hence as well as enabling attachment of an outboard motor 64, the unit provides for additional stowage both on deck and in a water tight condition below deck, of a considerable amount of equipment, which could not be safely carried by a conventional kayak.

One method of attaching an external motor to a boat such as a canoe or kayak, using the unit 30 of FIG. 4, involves attaching an outboard motor 35 to the unit 30 by clamping to the rear flange 34, or mounting a propulsion motor 48 within the unit 30 on the mounts 47. Then floating the unit 30 into position at the stem region 31 of the boat 32. The unit 30 is then attached to the stem region 31 with the attachment bolts 43 and 44. In the case of the inflatable pontoons 45 and 46, these are then inflated fully to secure to the stem region 31 of the boat 32.

Of course in the case of the outboard motor 35, this may be attached to the unit .oo.

*30 after the unit 30 has been secured to the stem region 31 in the above manner.

To attach an outboard motor to a boat such as a canoe or kayak, using the unit of FIG. 5, the unit 60 is first attached to the stem region 69 of the kayak 68 using the attachment bolts 77 to secure to the stem region 69 at the three locations. The outboard i motor 64 can then be attached to the rigid back wall 66 of the well region 65 when required. Of course the unit 60 may be used attached to the kayak 68 without the outboard motor, to simply provide stability and extra stowage capacity.

Herein the invention has been described with the motor mounting device adapted for mounting an outboard motor, or a motor for propulsion within the unit.

However, the invention is not limited to this, and the motor mounting device may be adapted for mounting other types of motor for propulsion such as motors with an inline propeller shaft and mounted on a pivot, motors for driving wind propellers, and motors for driving water jet propulsion units.

INDUSTRIAL APPLICABILITY 11 The buoyant stabilizer unit of the invention can be attached to a variety of water craft to provide extra stability, extra stowage capacity and enable the attachment of an external motor. The unit is particularly applicable to use with slender laterally unstable craft such as canoes and kayaks, extending the use of such craft. The invention thus has considerable industrial applicability.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the invention as defined by the appended claims.

.0

Claims (8)

1. A buoyant stabilizer unit comprising: a flotation member with an external surface portion adapted for abutting against a side surface of a boat hull at a location below a waterline of said boat hull and formed in a streamlined shape to minimize drag when abutted against said boat hull with said boat moving forward, said flotation member having a portion extending beyond the stem of said boat hull; and attachment means for attaching said unit to said boat hull.

2. A buoyant stabilizer unit according to claim 1, wherein said attachment device comprises a fastener for connecting between said unit and a structure of said hull.

3. A buoyant stabilizer unit according to either one of claim 1 and claim 2, further comprising motor mounting means for mounting a motor on said unit, for propulsion thereof.

4. A buoyant stabilizer unit according to any one of claim 1 through claim 3, further comprising a stowage compartment provided in said flotation member. A buoyant stabilizer unit according to any one of claim 1 through claim 4, wherein two of said flotation members are provided, and there is further provided: 0 a base member adapted for connection between said two flotation members so as 11 •to provide a sufficient mutual spacing to accommodate the stem region of a boat with 20 which the unit is to be used. S6. A buoyant stabilizer unit according to claim 5, further comprising motor mounting means for mounting a motor on said unit, for propulsion thereof. SO. S7. A buoyant stabilizer unit according to either one of claim 5 and claim 6, wherein said flotation members are formed integral with said base member. 25 8. A buoyant stabilizer unit according to any one of claim 5 through claim 7, wherein said attachment means comprises mating sections formed on said unit for 13 mating with a surface of said stem region of a boat to secure or assist in securing the boat to said unit.

9. A buoyant stabilizer unit according to any one claim 5 through claim 8, wherein said attachment means comprises an inflatable bladder positioned on inside surfaces of said flotation members and adapted for gripping against opposite sides of said stem region of a boat when inflated. A buoyant stabilizer unit according to any one of claim 5 through claim 9, wherein said motor mounting means is adapted for mounting an outboard motor on said unit.

11. A buoyant stabilizer unit according to any one of claim 1 through claim wherein all or part of said unit is molded by rotational molding.

12. A buoyant stabilizer unit substantially as described herein with reference to the appended drawings.

13. A method of attaching an external motor to a boat using a buoyant stabilizer 15 unit, substantially as described herein with reference to the appended drawings. eeoo Dated this 27th day of August 2001 :.7 Michael Heb en Bennett by his patent Attorneys M.J. SERVICE ASSOCIATES •o*