US20050229835A1

US20050229835A1 - Wash attenuator for a moored vessel

Info

Publication number: US20050229835A1
Application number: US10/982,838
Authority: US
Inventors: Russell Eathorne
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-04-15
Filing date: 2004-11-08
Publication date: 2005-10-20
Also published as: WO2005100146A1

Abstract

A wash attenuator for a moored vessel includes a buoyant member adapted to extend along at least a portion of the waterline of the vessel to isolate the portion of the waterline of the vessel from the wash. The buoyant member includes a first section extending above the water line and a second section extending below the water line. The wash attenuator further includes a barrier extending from the buoyant member and below the waterline for providing lateral stability to the buoyant member.

Description

FIELD OF THE INVENTION

The present invention relates to a wash attenuator for a moored vessel used to reduce the noise which is created within the vessel as a result of the wash impacting on the moored vessel at the waterline.
Throughout the specification the term “wash” includes waves generated by naturally occurring ocean currents, by wind, or by passing vessels or a similar action in a body of water upon which a vessel may be floating when moored and which are incident on the hull of the vessel. Accordingly, a “wash attenuator” is a device that is capable of reducing the strength of a wave.

BACKGROUND

In the case of vessels such as boats, which are moored, docked, or otherwise secured in a defined area on the water and which are used for accommodation purposes, one of the difficulties created by such circumstances is the noise generated within the hull of the vessel as a result of the wash incident upon the waterline of the vessel, which noise can cause difficulty to persons occupying the vessel and attempting to sleep.
In most cases vessels are moored by using cables or anchors to fix the position of the vessel. Frequently vessels are moored by attaching a cable from the bow or forwardmost point of the vessel to a fixed buoy or mooring. In this scenario, the vessel is free to move in response to changes in the direction of winds, currents or swells in such as way as to minimise the frictional resistance of the vessel to the wind, currents or swell. When this happens the longitudinal axis of the hull of the vessel tends to be aligned with the direction of the wind, currents or swell with the bow pointing directly into the wind. The wash which is incident on the moored vessel will thus first encounters the bow portion of the vessel. For most vessels, the shape of the bow section of the vessel is designed to minimise the frictional drag characteristics of the vessel's hull when the vessel is in motion through the water. Typically, the bow section tapers to a point at the forwardmost part of the vessel and, in side elevation, rises upwardly above the waterline. Whilst the shape of the bow section of the vessel may reduce frictional drag, it can also increase the level of noise created by wash incident on the underside of the bow portion of the vessel when the vessel is moored.
Other times, a vessel may be docked within a pen or other permanent structure located at a dock. Typically the pen is either floating or secured on poles and has an opening at one end to permit docking of the vessel within the pen. The orientation of the pen is fixed relative to the dock and thus when the vessel is moored within a pen, the vessel is not able to move freely to re-orient itself in response to changes in the direction of wind, current or swell. In this case, the wash may be incident on any portion of the vessel resulting in an unacceptably high level of noise for persons wishing to use the vessel for accommodation purposes.
It is an object of this invention to provide an attenuator which will reduce the noise created by the wash incident at the waterline of a moored vessel.
In the statement of invention and description of the invention which follow, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a wash attenuator for a moored vessel, the wash attenuator comprising:

- a buoyant member arranged to extend along at least a portion of the waterline of the vessel to isolate said portion of the waterline of the vessel from the wash, the buoyant member having a first section extending above the water line and a second section extending below the water line; and,
- a barrier extending from the buoyant member and below the waterline for providing lateral stability to the buoyant member.

Preferably, the barrier extends downwardly from the second section of the buoyant member. More preferably, the barrier extends substantially vertically downwardly from the second portion of the buoyant member.
In one example, the barrier is rigid to allow the barrier to retain its downwardly extending orientation relative to the buoyant member. Alternatively, the barrier is constructed of a flexible material and is provided with one or more weights arranged to maintain the downward orientation of the barrier relative to the buoyant member in use. Preferably the one or more weights are arranged to maintain verticality of the barrier relative to the buoyant member in use. In one example, the one or more weights are arranged along a lower edge of the barrier.
Advantageously, the length of the barrier may vary depending on the anticipated degree of wash to be attenuated. Similarly, the size and position of the one ore more weights may vary depending on the anticipated degree of wash.
For a moored vessel that is free to move in response to change in direction of the wind, current, or swell, the buoyant member preferably extends along at least a portion of the waterline of the vessel to either side of the bow section of the vessel.
More preferably the buoyant member extends along at least a portion of the waterline of the vessel to either side of the bow section of the vessel and along at least a portion of one or both sides of the hull of the vessel. The buoyant member may equally be arranged to extend along a portion of one or both sides of the hull of the vessel or along a portion of the rearward section of the vessel if required, particularly for vessels that are moored with a fixed orientation within a pen or dock.
When the vessel is a multi-hull vessel, each hull of the vessel having a bow section, a buoyant member may be arranged to extend along at least a portion of the waterline of the multi-hull vessel to either side of the bow section of each hull. Alternatively, the multi-hull vessel may be provided with a buoyant member arranged to extend along at least a portion of the waterline of one or both of the outermost hulls of the multi-hull vessel.
In one example of the present invention, the buoyant member comprises a plurality of buoyant member sections releasably coupled to each other in series to form the buoyant member. Advantageously adjacent buoyant member sections may be coupled together using hook and eye fasteners, string or any other suitable releasable mechanical fastening means.
In one embodiment, the buoyant member is inflatable so as to be able to be stored in an uninflated condition to occupy less space on the vessel. The inflatable buoyant member may be fitted with one or more relief valves to avoid over inflation. Where the buoyant member comprises a plurality of buoyant member sections, each section may include an inlet for inflating or deflating the buoyant member section. Each buoyant member or buoyant member section may be inflated manually or be self-inflatable.
In one example, the buoyant member further comprises one ore more elongate members projecting upwardly from the first section of the buoyant members for holding an advertising banner.
In an alternative embodiment, the buoyant member may be of fixed shape and be hollow or solid provided only that the buoyant member or buoyant member sections are able to float on water.
The cross-sectional profile of the buoyant member or buoyant member sections may be any shape with an inflatable buoyant member having a circular cross-section in one example described herein. For a rigid buoyant member, the cross-section may be rectangular or square for ease of fabrication or could equally be circular in cross-section and constructed from hollow pipe or tube stock. The cross-sectional profile of the buoyant member may vary along its length. Preferably the buoyant member terminates in first and second opposed ends and the cross-sectional area of the buoyant member tapers towards one or both of the first and second ends.
The buoyant inflatable members may further comprise a plurality of nested liners to mitigate the risk of deflation in the event of an outer liner receiving a puncture.
Preferably the buoyant member includes one or more attachment point(s) for securing the position of the buoyant member relative to the vessel, a pen or a mooring. Preferably, the buoyant member is releasably connected directly to the vessel using an attachment means extending from the vessel, pen or mooring to one or more attachment points on the buoyant member.
In one example, the buoyant member is provided with one or more spacing means for holding the buoyant member in a spaced apart relationship to the hull of the vessel. The spacing means is an optional feature for reducing wear or noise associated with rubbing of the buoyant member on the hull of the vessel. The buoyant member may equally be held in a spaced apart relationship away from the vessel indirectly using a spacer applied to a mooring rope extending from the vessel to the mooring or pen. The spacer effectively pulls the buoyant member away from the vessel but does not lift the buoyant member out of the water.
According to a second aspect of the present invention there is provided a pen for mooring a vessel, the pen including a wash attenuator according to the first aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a more comprehensive understanding of the nature of the invention, preferred embodiments of the process in accordance with the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic view of an inflatable wash attenuator according to a first embodiment in its inflated condition and arranged around the bow section of a vessel that is able to re-orient itself in response to changes in the direction of the prevailing winds, current or swell and the wash attenuator is arranged around the bow section of the vessel;
FIG. 2 is an isometric view of the wash attenuator of FIG. 1;
FIG. 3 is a cross-section of the wash attenuator of FIG. 2 in a deflated condition;
FIG. 4 is a side elevation of the wash attenuator of FIG. 3;
FIG. 5 is a schematic overhead view of a wash attenuator according to a second embodiment and arranged around the stern section of a vessel that is moored in a pen and is unable to re-orient itself in response to changes in the direction of the prevailing winds, current or swell;
FIG. 6 is an isometric view of the wash attenuator of FIG. 5 showing a rectangular cross-sectional profile of a buoyant member of a fixed shape;
FIG. 7 is cross-sectional view of a wash attenuator for which the barrier comprises a first and second strip in an inverted “V” formation extending downwardly from the buoyant member;
FIG. 8 is a cross-sectional view of an inflatable wash attenuator for which the barrier is substantially triangular in cross-section;
FIG. 9 is a schematic overhead view of a wash attenuator according to a third embodiment and arranged around a multi-hull vessel that is moored to a mooring and thus able to re-orient itself in response to changes in the direction of the prevailing winds, wash, current or swell; and,
FIG. 10 is a side view of the embodiment illustrated schematically in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Before the preferred embodiments of the present methods are described, it is understood that this invention is not limited to the particular design of vessel described. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Although other types of vessels or materials to those described herein can be used to practice or test the various aspects of the present invention, preferred means are now described with reference to the drawings.
The term “buoyant member” is used throughout this specification to describe a member that is able to float on water in such as way that the member rises and falls with any change in water level.
The term “waterline” refers to the line on the hull of a vessel to which the surface of the water upon which the vessel is floating rises.
The term “vessel” is used to describe any water-going craft of sufficient size to permit accommodation of a person within the hull of the vessel, including but not limited to boats, canoes, ships, yachts, catamarans, trimarans, ferries, liners, or tankers. Accordingly, the vessel may have one or more hulls, the “hull” of the vessel being understood to be the main body or frame of the vessel excluding masts, engines or superstructure.
A “moored vessel” refers to a vessel that is at least temporarily secured within a defined area. This may be achieved by means of an anchor dropped to the seabed, a cable or line secured to a mooring or a bollard on a wharf, or by docking the vessel within a fixed pen or dock. The vessel may thus be moored in such a way as to have a fixed orientation relative to prevailing winds, currents or swells (such as when the vessel is moored within a pen) or be able to move freely so as to align its orientation to minimise frictional resistance to the prevailing winds, currents or swells (such as when the vessel is moored at a mooring).
A “mooring” is understood to be a permanent anchoring device, the position of which is fixed relative to the seabed and is typically marked with a buoy. In ordinary use, the vessel would be moored to a mooring using a rope or cable extending from the vessel and secured to the buoy.
The term “bow” refers to the forwardmost point at the front of the vessel. The term “bow section” accordingly refers to the forwardmost section of the hull of the vessel. Typically the sides of the hull of the vessel are substantially parallel to one another with the bow section of the vessel intersecting the sides of the hull at a gradual or abrupt angle depending on the design of the hull.
The term “chine” refers to the intersection of the sides of the hull with the bottom of the hull. A vessel with a “hard chine” is one that has an abrupt change in angle at the intersection of the sides of the hull and the bottom of the hull. Such vessels are more susceptible to the slapping noise generated with wash is incident on the vessel.
A first embodiment of the present invention is illustrated in FIGS. 1 to 4 in which a vessel 10 in the form of a V-bottom boat is moored to a mooring 12 and is thus able to re-orient itself in response to changes in the direction of wind, wash, current or swell. In this example, the prevailing wind direction can be assumed to be from the left hand side of the page towards the right hand side of the page in relation to FIG. 1. A wash attenuator 14 is releasably connected to the boat 10 to isolate the waterline 16 at the bow section 18 of the boat 10 from the action of the wash of the water upon which the boat when moored.
The wash attenuator 14 comprises a buoyant member 20 adapted to extend along the waterline 16 of the bow section 18 of the boat 10 and along at least a portion of the each side 22 of the hull 24 of the boat 10. The buoyant member 20 has a first section 26 extending above the waterline and a second section 28 extending below the waterline. The wash attenuator 14 further comprises a barrier 24 extending from the buoyant member 20 and below the waterline for attenuating the waves and providing lateral stability to the buoyant member 20.
In the illustrated example of FIGS. 1 to 4, the barrier 24 is in the form of a single flexible strip of material that extends substantially vertically downwardly from the second section 28 of the buoyant member 20 and is provided with one or more weights 30 arranged to maintain verticality of the barrier 24 relative to the buoyant member 20 in use. The relative sizes of the first and second sections 26 and 28 of the buoyant member 20 may vary provided only that at least a portion of the buoyant member 20 remains at all times above the water. If the buoyant member is fully submersed below the water, it no longer provides a barrier to the wash which is then able to pass over the buoyant member and impact on the vessel.
The width of the barrier 24 can vary depending on the anticipated degree of wash to be attenuated. The wider the barrier 24 the more effective the wash attenuator 14 is at reducing the strength of the wash.
The wash attenuator 14 of the illustrated example shown in FIGS. 1 to 4 is inflatable for ease of storage when not in use. In this example, the wash attenuator 14 is constructed using a single sheet of suitable impervious plastics material which is folded and welded and/or stitched and/or glued or similarly bonded at a junction 32 of the fold as shown at FIGS. 3 and 4 to form the buoyant member 20. The barrier 24 is defined by the remaining non-folded portion of the single sheet of material which extends beyond the bonded junction 32. Using this form of construction, the cross-sectional profile of the buoyant member 20 is circular when in its inflated condition. Other cross-sectional profiles could equally be used when the buoyant member is non-inflatable.
The barrier 24 terminates at a lower edge 34 of the sheet of material which in turn is folded over to form a hem 36 within which the one or more weights 30 are retained. In this example, the one or more weights 30 are provided using a length of cable or chain or the like but may equally comprise a series of weights located at spaced apart intervals along the hem 36.
A transverse bonded junction 38 is also provided at the longitudinal centreline of the wash attenuator 14 to provide a fold line for arranging the buoyant member 20 in a V-shaped configuration so that the buoyant member 20 can extend to either side of the bow section 18 of the boat 10 in use.
To avoid over inflation, the inflatable buoyant member 20 is fitted with one or more relief valves 40.
The wash attenuator 14 is further provided with attachment points 42 for securing the position of the buoyant member 20 relative to the boat 10 using one or more securing lines 48.
In the illustrated example of FIGS. 1 to 4, the moored vessel is free to move in response to change in direction of the wind, current or swell. Accordingly the buoyant member 20 is releasably attached to the boat using one or more securing lines 48 extending from the attachment points 42 of the buoyant member to a corresponding number of bollards 44 provided on the boat 10. The buoyant member is V-shaped with the point of the “V” of the buoyant member 20 being positioned adjacent the bow 46 of the boat 10. The buoyant member 20 also extends along at least a portion of the sides 22 of the hull of the vessel to reduce the noise within the hull.
It will be readily apparent from the illustrated embodiments that a portion of the wash attenuator extends above and below the waterline and thus isolates the wash incident upon the hull of the vessel to either side of the bow. As a result, the strength of the wash is substantially reduced and the noise within the hull of the vessel is reduced as a result. It will be appreciated that the length of the wash attenuator 14 may be varied according the design of the vessel 10 and the anticipated size of the wash to be attenuated.
The inflatable member may be self-inflating in an analogous fashion to self-inflatable camping beds and the like. Such devices typically rely on the use of a resiliently compressible means (not shown) which defines the shape and volume of the self-inflating device when fully expanded, the resiliently compressible means being retained within the body of the device. When the self-inflating device is not in use, the resiliently compressible means is collapsed within the body of the device and constrained to occupy a smaller volume. To self-inflate the device, a seal is opened to allow fluids to enter the body of the device and the resiliently compressible means is released to resume its expanded configuration, thereby increasing the volume of the body of the device. As the volume of the body increases, fluid such as air is sucked into the body to fill the vacuum created.
A second example of the wash attenuator 14 is illustrated in FIGS. 5 to 7 for which like reference numerals refer to like parts. In this example, the vessel 10 is moored in a pen 50 so that the orientation of the vessel 10 relative to the prevailing winds, currents, or swell is fixed. The pen 50 is substantially U-shaped, having a opening 54 to allow the vessel 10 to enter the pen 50 and be docked therein. In this example, the dominant direction of wash that is incident on the hull of the vessel 10 is assumed to be coming from the stern 52 towards the bow 46. When this is the case, maximum wave and thus noise attenuation is achieved by arranging the buoyant member 20 to extend around the stern 52 and along a portion of the sides 22 of the vessel 10. For pens where the dominant wind direction is from the bow to the stern of the vessel, the buoyant member 20 would best be arranged around the bow section 18 of the vessel 10. For pens where the dominant wind direction is across the vessel from one side to the other, the buoyant member 20 would best be arranged along a portion of the waterline 16 of the side 22 of the vessel 10 that is upwind.
In the illustrated example of FIG. 6, the barrier 24 is rigidly constructed from a substantially flat metal strip which extends vertically downwardly from the second section 28 of a non-inflatable buoyant member 20. The buoyant member 20 in this embodiment is hollow, having a rectangualar cross-section and being constructed from a welded lightweight metal such as aluminium.
It is to be understood that the barrier 24 need not be flat, but could equally have an inverted V-shaped configuration as shown in FIG. 7 in which the barrier is constructed using a first and a second rigid strip 56 and 58, respectively each extending downwardly from the buoyant member 20 and below the waterline 16. The first and second strips 56 and 58 respectively, extend downwardly from the second section 28 of the buoyant member 20 at an angle to each other. The first and second strips 56 and 58 could equally be arranged at the lowermost edge 59 of the barrier 24 shown in FIG. 6, forming an inverted Y-section.
A further alternative arrangement for the barrier 24 is shown in FIG. 8 in combination with an inflatable buoyant member 20. In this example, the barrier 24 has a substantially triangular cross-section and extends longitudinally along and symmetrical with the centreline of the second section 28 of the buoyant member 24. In this arrangement, the barrier 24 may be inflatable with or independently of the buoyant member 20. The barrier could equally be constructed of a rigid material and be solid or hollow. In the arrangement shown in FIG. 8, the buoyant member is provided with a plurality of nested liners 84 to mitigate the risk of deflation in the event of an outer liner receiving a puncture.
In the second embodiment of the present invention illustrated in FIGS. 5 and 6, the buoyant member 20 is provided with one or more spacing means 60 in the form of rubber projections for holding the buoyant member 20 in a spaced apart relationship from the hull of the vessel 10. It is to be understood that the buoyant member 20 need not be spaced apart from the vessel 10 in order to attenuate the wash that is incident on the vessel, the spacing means being used to reducing wear or noise associated with rubbing of the buoyant member 20 on the hull of the vessel 10. The buoyant member 20 is not coupled directly to the vessel 10 but is rather releasably coupled to one or more bollards 64 provided on the pen 50 using securing lines 48 extending from the attachment points 42 to the bollards 64.
A third embodiment of the present invention is illustrated in FIGS. 9 and 10 for which like reference numerals refer to like parts. In this embodiment, the vessel 10 a multi-hull vessel and more particularly a trimaran. The trimaran has a centre hull 70 positioned between two outermost hulls 72. Each of the three hulls of the trimaran 10 has a bow section 18 and in this example, the buoyant member is arranged to extend around the bow 46 of the trimaran and along at least a portion of the waterline of the outermost hulls 72. Alternatively, a plurality of smaller wash attenuators 14 could be positioned around each of the outermost hulls 72 and/or the centre hull 70.
In this example, the buoyant member 20 is held in a spaced apart relationship away from the trimaran 10 indirectly using a spacer 74 positioned at the base 76 of the securing line 48 extending from the bow 46 of the centre hull 70 of the trimaran to a mooring 80. The spacer 74 effectively pulls the buoyant member 20 away from the trimaran 10 but does not lift the buoyant member 20 out of the water.
Numerous variations and modifications will suggest themselves to persons skilled in the relevant art, in addition to those already described, without departing from the basic inventive concepts. For example, the buoyant member may equally comprise a plurality of buoyant member sections releasably coupled to each other in series to form the buoyant member. Using this arrangement, adjacent buoyant member sections can be coupled together using hook and eye fasteners, string or any other suitable releasable mechanical fastening means. All such variations and modifications are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description and the appended claims.

Claims

1. A wash attenuator for a moored vessel, the wash attenuator comprising:

a buoyant member adapted to extend along at least a portion of the waterline of the vessel to isolate said portion of the waterline of the vessel from the wash, the buoyant member including a first section extending above the water line and a second section extending below the water line; and,

a barrier extending from the buoyant member and below the waterline for providing lateral stability to the buoyant member.

2. A wash attenuator as defined in claim 1 wherein the barrier extends downwardly from the second section of the buoyant member.

3. A wash attenuator as defined in claim 1 wherein the barrier extends substantially vertically downwardly from the second portion of the buoyant member.

4. A wash attenuator as defined in claim 1 wherein the barrier is rigid.

5. A wash attenuator as defined in claim 3 wherein the barrier is constructed of a flexible material and is provided with one or more weights arranged to maintain substantial verticality of the barrier relative to the buoyant member in use.

6. A wash attenuator as defined in claim 5 wherein the one or more weights are arranged along a lower edge of the barrier.

7. A wash attenuator as defined in claim 1 wherein the buoyant member extends along at least a portion of the waterline of the vessel to either side of the bow section of the vessel.

8. A wash attenuator as defined in claim 1 wherein the buoyant member extends along at least a portion of the waterline of the vessel to either side of the bow section of the vessel and along at least a portion of the sides of the hull of the vessel.

9. A wash attenuator as defined in claim 1 wherein the buoyant member is arranged to extend along a portion of one or both sides of the hull of the vessel

10. A wash attenuator as defined in claim 1 wherein the buoyant member is arranged to extend around a portion of the rearward section of the vessel.

11. A wash attenuator as defined in claim 1 wherein the vessel is a multi-hull vessel, each hull of the vessel including a bow section, and the buoyant member is arranged to extend along at least a portion of the waterline of the vessel to either side of the bow section of each hull.

12. A wash attenuator as defined in claim 1 wherein the vessel is a multi-hull vessel, each hull of the vessel including a bow section, and the buoyant member is arranged to extend along at least a portion of the waterline of one or both outermost hulls of the multi-hull vessel.

13. A wash attenuator as defined in claim 1 wherein the buoyant member comprises a plurality of buoyant member sections releasably coupled to each other in series to form the buoyant member.

14. A wash attenuator as defined in claim 1 wherein the buoyant member is inflatable.

15. A wash attenuator as defined in claim 1 wherein the buoyant member is of fixed shape and is hollow.

16. A wash attenuator as defined in claim 1 wherein the buoyant member terminates in first and second opposed ends and the cross-sectional area of the buoyant member tapers towards one or both of the first and second ends.

17. A wash attenuator as defined in claim 14 wherein the inflatable buoyant member further comprises one or more nested liners.

18. A wash attenuator as defined in claim 1 further comprising one or more attachment points for securing the position of the buoyant member relative to the vessel, a pen or a mooring.

19. A wash attenuator as defined in claim 1 wherein the buoyant member is provided with one or more spacing means for holding the buoyant member in a spaced apart relationship to the vessel.

20. A wash attenuator as defined in claim 1 wherein the buoyant member is held in a spaced apart relationship away from the vessel indirectly using a spacer applied to a mooring rope extending from the vessel to a mooring or a pen.

21. A wash attenuator as defined in claim 1 in combination with a pen within which a vessel may be moored.