Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
IMPROVEMENTS IN/OR RELATING TO BALLAST SYSTEMS AND RELATED MEANS OF OR FOR A YACHT
Document Type and Number:
WIPO Patent Application WO/2005/085060
Kind Code:
A1
Abstract:
A canting keel structure of or for a yacht, comprising or including, a fin, vertically split to define two or more fore/aftwardly disposed individual fin portions, a ballast means split into two or more individual ballast portions each engaged or forming part of or dependent from a respective the fin portions, one or more pivot means to allow canting of the fin portions about a pivot axis extending parallel to the longitudinal axis of the yacht, wherein, in use when fitted to a hull of the yacht, each the fin and ballast portions (as a unit) can be individually canted (preferably at least in part independent from the other of the fin and ballast portions) about the pivot axis by the pivot means.

More Like This:
Inventors:
Clair St., Brown Charles Robert (37 Marine Parade, Herne Bay, AUCKLAND, NZ)
Buckley, Stewart Ian (50A Arney Crescent, Remuera, AUCKLAND, NZ)
Elliott, Greg Mervyn (121 Hinemoa Street, Birkenhead, AUCKLAND, NZ)
Hendy, George Alan (27 Sylvan Avenue, Northcote, AUCKLAND, NZ)
Longdill, Simon James (9 Bowden Road, Mt Wellington, AUCKLAND, NZ)
Oliver, James Clayton (219 Westland Road, Annapolis, MD, 21401, US)
Application Number:
PCT/NZ2005/000040
Publication Date:
September 15, 2005
Filing Date:
March 08, 2005
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
BUCKLEY SYSTEMS LIMITED (9-11 Bowden Road, Mt Wellington, AUCKLAND, NZ)
ESPORT VENTURES LIMITED (Level 2, 75 Queen Street, AUCKLAND, NZ)
Clair St., Brown Charles Robert (37 Marine Parade, Herne Bay, AUCKLAND, NZ)
Buckley, Stewart Ian (50A Arney Crescent, Remuera, AUCKLAND, NZ)
Elliott, Greg Mervyn (121 Hinemoa Street, Birkenhead, AUCKLAND, NZ)
Hendy, George Alan (27 Sylvan Avenue, Northcote, AUCKLAND, NZ)
Longdill, Simon James (9 Bowden Road, Mt Wellington, AUCKLAND, NZ)
Oliver, James Clayton (219 Westland Road, Annapolis, MD, 21401, US)
International Classes:
B63B41/00; B63B39/06; B63B43/08; (IPC1-7): B63B41/00
Domestic Patent References:
WO1987000136A1
WO1989009159A1
WO2001081165A1
Foreign References:
FR2639018A1
US4686922A
DE3713176A1
US5967074A
US5152238A
US4044703A
DE2947523A1
Attorney, Agent or Firm:
Adams, Matthew D. (A J Park, 6th Floor Huddart Parker Building PO Box 94, Wellington 6015, NZ)
Download PDF:
Claims:
CLAIMS:
1. A canting keel structure of or for a yacht, comprising or including, a fin, vertically split to define two or more fore/aftwardly disposed individual fin portions, a ballast means split into two or more individual ballast portions each engaged or forming part of or dependent from a respective said fin portions, one or more pivot means to allow canting of said fin portions about a pivot axis extending parallel to the longitudinal axis of said yacht, wherein, in use when fitted to a hull of said yacht, each said fin and ballast portions (as a unit) can be individually canted (preferably at least in part independent from the other of said fin and ballast portions) about said pivot axis by said pivot means.
2. A structure of claim 1 wherein said canting is about a pivot axis positioned at the hull skin of the yacht.
3. A structure of claims 1 or 2 wherein said fin is split to define said individual fin portions about a plane or planes transverse to said fore/aft line of said yacht (e. g. preferably in a portstarboard orientation), to position a first fin portion forward more of the other fin portion (s).
4. A structure of any one of claims 1 to 3 wherein said ballast means is dependent from said fin and is split about a plane or planes extending in the fore/aft direction and preferably vertically.
5. A structure of any one of claims 1 to 4 wherein said ballast means is dependent from said fin and is split about a plane or planes which allow separation of said ballast portions and said fin portions in a direction lateral to the fore/aft direction of said yacht.
6. A structure of any one of claims 1 to 5 wherein each said fin portion includes a ballast portion.
7. A structure of any one of claims 1 to 5 wherein each said fin portion has disposed at its distal most end away from said hull, a respective ballast portion.
8. A structure of any one of claims 1 to 7 wherein each said ballast portion is at least in part in a lateral to the fore/aft direction overlap to each other.
9. A structure of any one of claims 1 to 7 wherein each said ballast portion is at least in part in a lateral (to the fore/aft direction and lateral to the elongate direction of the fin portion) overlap relative to the other of said ballast portions, when such are in abutting relation.
10. A structure of any one of claims 1 to 7 wherein each said ballast portion is at least in part in a lateral (to the fore/aft direction and lateral to the elongate direction of the fin portion) overlap relative to the other of said ballast portion (s) when said respective fin portions are in a coplanar relationship with each other.
11. A structure of any one of claims 1 to 7 wherein each said ballast portion is at least in part in a lateral (to the fore/aft direction and parallel to the elongate direction of the fin portion) overlap relative to the other of said ballast portions.
12. A structure of any one of claims 1 to 7 wherein each said ballast portion is at least in part in a lateral (to the fore/aft direction and parallel to the elongate direction of the fin portion) overlap relative to the other of said ballast portions when said fin portions are in a coplanar relationship with each other.
13. A structure of any one of claims 1 to 7 wherein each said ballast portion is at least in part in a lateral (to the fore/aft direction and parallel and transverse to the elongate direction of the fin portion) overlap relative to the other of said ballast portions when said fin portions are in a coplanar relationship with each other.
14. A structure of anyone of claims 8 to 13 wherein said overlap allows for a first fin portion to pivot about the pivot axis independent from the other fin portion towards one side only of the other of said fin portions.
15. A structure of any one of claims 1 to 14 wherein said fin portions are selectively engageable, one to the other, to in an engaged condition forming a coplanar fin structure.
16. A structure of claim 15 wherein said selective engagement is at least by complementary engagement of said fin portions to each other, along at least in part their said split plane.
17. A structure of any one of claims 1 to 16 wherein, when in a coplanar condition, said fin portions can be canted either side of the vertical centreline plane of said yacht by said pivot means.
18. A structure of any one of claims 1 to 17 wherein said pivot means includes an actuator to actuate pivotal movement.
19. A structure of any one of claims 1 to 18 wherein said rotation occurs about an axle rigidly fixed to said hull.
20. A structure of any one of claims 1 to 19 wherein said fin portions may also translate relative to each other in a in a fore/aft direction, to move into and out of an overlapping relationship with each other.
21. A structure of claim 18 wherein said actuator is contained in said hull.
22. A structure of any one of claims 1 to 21 wherein said pivot means is disposed within said hull and includes a rack and pinion means, with which said actuator is in operative engagement.
23. A structure of any one of claims 1 to 21 wherein said pivot means consists of a rack and pinion arrangement for each of said fin portions, wherein for each fin portion one of said rack and pinion is carried by said fin portion and the other of said rack and pinion is carried engaged to said hull, and wherein an actuator is in operative engagement with said pinion to drive said pinion for its movement along said rack.
24. A structure of any one of claims 1 to 23 wherein wing members are deployable, each independently of each other, from one or each of the end of said fin portions and/or ballast portions.
25. A structure of claim 24 wherein said wing members are deployable from a condition whereby they are at least partially contained in the ballast and/or fin portions to a fully deployed condition.
26. A structure of any one of claims 1 to 25 wherein the stern most fin portion includes a trim tab extending at least along part of the trailing edge of the stern most fin portion and pivotable about a pivot axis in plane with the chord of the stern most fin portion.
27. A structure of any one of claims 1 to 26 wherein the forward most fin portion includes a trim tab disposed to its leading edge and extending at least along part thereof, and being pivotable to the forward most fin portion about an axis parallel to the chord of the forward most fin portion.
28. A canting appendage structure of or for a hull comprising or including: a fin depending from said hull pivotable at or proximate its hull proximal end about an axis parallel to the fore/aft plan of said hull, said fin comprising at least two separate fin portions each independently pivotable about said axis and capable of alignment to assume a coplanar configuration, an actuation means for each of said fin portions to effect said pivot, wherein said fin portions can be canted together as a single unit when in said coplanar configuration or individually to both sides of said hull centre line by said actuation means.
29. A structure of claim 28 wherein said canting appendage structure also includes a ballast means split (preferably longitudinally) into two separate (preferably port and starboard more) ballast portions, one each associated with one of said fin portions.
30. A structure of claims 28 or 29 wherein said actuation means are interior of said hull and act on said fin portions also extending in part interior of said hull, and to the opposite side of said axis of rotation to the exterior to the hull portion of said fin portion.
31. A structure of any one of claims 28 to 30 wherein each said actuation means is a hydraulically actuated pinion gear which is affixed to a said fin portion, each pinion gear in meshing engagement with a rack affixed to said hull.
32. A structure of claim 31 wherein said rack is shaped to track the movement of said pinion gear about said pivot axle.
33. A structure of any one of claims 28 to 32 wherein said fin portions are fore and aft more disposed fin portions and selectively engageable along transverse to the longitudinal fore/aft direction mating surfaces, to assume the coplanar single unit condition.
34. A structure of claim 33 wherein said fin portions are engaged by at least one locking means disposed at mating surfaces of said fin portions.
35. A structure of claims 33 or 34 wherein one or each said fin portions can translate in said fore/aft direction (preferably along said axle member) to engage or disengage from one another in and out of said complimentary engagement.
36. A structure of claim 28 wherein said actuation means includes of a pinion gear, attached to or proximal to said hull proximal end of each said fin, trackable in a corresponding rack attached to said hull.
37. A structure of claim 28 wherein there are wing members deployable from said appendage structure.
38. A structure of any one of claims 28 to 37 wherein each ballast portion has a wing member pivotally deployable therefrom.
39. A structure of claim 38 wherein deployment of each said wing fin member is independently controllable.
40. A structure of claim 28 wherein the stern most fin portion includes a trim tab extending at least along part of the trailing edge of the stern most fin portion and pivotable about a pivot axis in plane with the chord of the stern most fin portion.
41. A structure of claim 28 wherein the forward most fin portion includes a trim tab disposed to its leading edge and extending at least along part thereof, and being pivotable to the forward most fin portion about an axis parallel to the chord of the forward most fin portion.
42. A wing member of or for a keel (preferably canting keel) structure located at a position at or near the hull distal most region of a keel structure, said wind member being deployable and from a retracted within a cavity of said keel position to a position where it extends from said keel, to provide increased hydrodynamic lateral resistance to counteract the reduced lateral resistance experienced by a canted keel or keel (s).
43. A wing member of claim 42 wherein there are two such wing members, one each side of the centreline plane of said keel structure.
44. A wing member of any one of claims 42 or 43 wherein said wing member (s) are deployable from a ballast bulb of said keel structure which is disposed at the distal end of a fin of said keel structure.
45. A wing member of claim 44 wherein said wing member (s) can be at least partially contained in and deployed from said ballast member of said keel structure.
46. A wing member of any one of claims 42 to 45 wherein said wing member (s) can be deployed independently of one another.
47. A wing member of any one of claims 42 to 46 wherein either or both of said wing member (s) are movable (preferably by rotation) to be inclined to the incident water flow to increase the lift of the keel structure.
48. A wing member of claim 42 wherein the angle of incidence of said wing member (s) to said incident water flow is adjustable.
49. A canting keel incorporating a wing member or members as herein described with reference to the accompanying drawings.
50. A hull of a yacht which incorporates a canting keel having a wing or wing members as claimed in claim 42.
51. A canting keel appendage of a yacht of a kind which includes a foil extending from a pivot axis parallel with the fore/aft vertical plane of said yacht to the exterior side of the hull of said yacht and a lever arm interior of said hull acting on (and preferably forming part of) said foil, said means comprising, (a) a rack, fastened to said hull (b) a pinion, attached lever arm and operatively engaged with said rack (c) a prime mover to actuate relative movement of said rack and said pinion.
52. An appendage of claim 51 wherein said prime mover drives said pinion rotationally to displace it along said rack to induce cant on said keel appendage about said pivot axis preferably defined by an axle member fastened to said hull.
53. An appendage of claim 51 wherein said rack is curved over the locus of movement of said pinion.
54. An appendage of claim 52 wherein said curve is equidistant from said axle member.
55. An appendage of claim 51 wherein said pinion is driven hydraulically by said prime mover.
56. An appendage of claim 51 wherein said rack is lateral to the fore/aft direction of said hull.
57. An appendage of claim 51 wherein said pinion is driven through a planetary gear box or equivalent torque stepping means.
58. A keel appendage, comprising or including, a first forward more keel appendage portion a second rearward more keel appendage portion, each keel appendage portion mounted at least translationally on a common translation slide, or axle member, a prime mover acting on one or both of said first and second portions, wherein said prime mover is in operative engagement with at least on of said keel appendage portions to cause translational movement of said portion relative to said axle member.
59. A keel assembly for a boat hull or a boat hull including a keel assembly, the assembly being deployed or deployable to define a hull centred keel with a centred ballast means, wherein the keel is portionable so as to allow one portion to cant in one direction from the centre and another portion to cant in the other direction from the centre, or from the first mentioned portion, and wherein each portion of the keel portions can carry with it a portioned part of the ballast means.
60. An assembly of claim 59 wherein the keel assembly may preferably also include the trailing edge trim tab or leading edge trim tabs as herein described.
61. An assembly of claim 59 wherein the portioning is of the keel is not in a plane on which the keel can be centred but rather on either side of a separation to allow portioning transverse of the main hull axis.
62. A structure of claim 28 wherein said centred ballast means is a bulb structure depending from said hull centred keel.
63. A canting keel as herein described with reference to one or more of the accompanying drawings.
64. A method of trimming a yacht by canting a keel of a kind as hereinbefore defined.
65. A method of mooring a yacht by splitting the fins of a keel as hereinbefore defined by each fin being rotated to opposite sides of the centre line of said yacht.
66. A method of claim 65 wherein said rotation to opposite sides of the centre line reduces the draft of the yacht.
67. An apparatus to provide a cantable keel, draft reduction and retractable fins for operative association with a hull and components to provide a canting keel as herein described with reference to the accompanying drawings.
68. A hull including a canting keel as claimed in any one of claim 1,51 or 57.
69. A yacht including a canting keel as claimed in any one of claim 1,51 or 57 or 72.
70. A canting keel of or part of a yacht comprising: a) a main foil portion pivotally engaged with the hull of a vessel in order to allow it to cant about a generally fore/aft aligned pivot axis, b) optionally a ballast means disposed to the end of the foil portion distal most from the hull, c) at least one trim tab disposed in a location selected from (i) the leading edge of said foil and (ii) the trailing edge of said foil, d) said trim tab extending along at least part of the foil and pivotable relative to the foil about an axis in plane with the chord of the foil.
71. An keel of claim 70 wherein there are disposed two trim tabs to the foil one on the leading edge of the foil and one on the trailing edge of the foil.
72. A means for canting a keel appendage of a yacht of a kind which includes a foil extending from a pivot axis parallel with the fore/aft vertical plane of said yacht to the exterior side of the hull of said yacht and a lever arm interior of said hull acting on (and preferably forming part of) said foil, said means comprising, (a) a pinion fastened to said hull (b) a rack, attached lever arm and operatively engaged with said rack (c) a prime mover to actuate relative movement of said rack and said pinion.
Description:
IMPROVEMENTS IN/OR RELATING TO BALLAST SYSTEMS AND RELATED MEANS OF OR FOR A YACHT FIELD OF THE INVENTION The present invention relates to a ballast system and related means of or for a yacht.

In particular, although not solely, it relates to a canting ballast appendage such as a canting keel of or for a yacht.

BACKGROUND OF THE INVENTION Where reference herein is made to a keel or keel structure it is to be understood that such includes means which in more modern parlance may also be referred to as a hull appendage of a kind including or carrying some form of ballast such as a bulb disposed at the lower most end of the hull affixed fin or foil disposed to extend below the water line of a yacht.

The term ballast structure as may herein be used may also be considered synonymous with such means, generally disposed exterior to the hull of a yacht, for providing a righting moment therefor.

The ability of a yacht to counteract the heeling moment when under sail has up until recently, been limited to fixed keel structures performing two inherent tasks ; providing lateral resistance for the yacht to reduce sideways slip (leeway) and providing ballast, to counter any heeling moment developed by the sail and rig structure.

Advances in this concept have been seen whereby a large heavy bulb is supported by a high aspect ratio foil located and extending beneath the hull of a yacht. In most instances, the bulb is constructed from lead or a similar high density material and the supporting fin is manufactured to form a solid or hollow structure.

To increase the sailing performance of a yacht, progression in keel technology has seen the development of canting keel structures whereby the

supporting fin and bulb are rotated ("canted") about a central longitudinal axis to the yacht, toward the windward side of the yacht as for example described in publication US 5,622, 150. Canting of the ballast structure to increase righting moment may occur at any point of sail. Such structures have found application on various length yachts particularly for which speed and performance has been a prime design consideration. In this instance, design emphasis is placed upon reducing the beam at water line of the hull and maximising available sail area. It is generally known that narrow beamed boats are faster than wider beamed boats.

A combination of slender or narrow hull envelopes and larger sail areas requires an effective and efficient means for ballasting the boat for optimum sailing performance. Increased performance may be obtained by increasing the length of the supporting fin structure such that the righting moment can be improved when the ballast structure is in a canting position. As a consequence, however, maximising the length of the draft of the yacht may restrict the ability of the yacht to operate in shallow coastal or harbour waters. The moment created about the pivot fulcrum of a deep keel is also significantly large and needs to be dealt with by the mechanism to actuate a canting condition. Also, the mooring or berthing a yacht with significant draft can be restrictive or prohibitive in certain harbour regions or marinas.

To remedy the problems of excessive draft, prior art keel structures have been designed with the ability to retract vertically inside the hull to reduce the effective draft. Such reduction becomes convenient for the purposes of manoeuvring the boat through harbour and water ways toward berthing positions where shallow water can cause inconveniences such as limiting travel times or prohibiting travel completely. Providing for a retraction means for a canting keel structure becomes one of practical convenience rather than assisting and enhancing the performance of the yacht by encouraging hull design with reduced beam.

The prior art presents a variety of solutions dealing with canting keel structures whereby the intention of the mechanism is to cant the ballast weight to

increase the righting moment of the yacht. Notably, publications WO 01/81165, US 5,152, 238 and EP 0855339 all describe multiple or split keel structures in which a mutual rotation of either split or multiple keel fins facilitates the canting of a supporting ballast means. In this regard, publications WO 01/81165 and US 5,152, 238 describe mechanisms where a single fin structure is of a split form and is able to separate in a longitudinal manner allowing both separations to cant independently to opposite sides such that a neutral balance point is maintained for the purpose of reducing draft for shallow waters and the like.

Mechanisms providing the canting ability of the keel ballast structures are generally actuated using hydraulic means such as a hydraulic ram whereby hydraulic actuators are positioned within the hull. The foil section of a keel is pivoted about a longitudinal axis of the hull and further extends into the hull, providing a lever which interacts with the hydraulic rams. The hydraulic rams then act upon the lever and are able to impose sufficient moment to rotate the supporting fin structure and therefore cant the ballast means to a specified angle.

The implementation of such a system produces several known disadvantages.

The first disadvantage that can be seen is that hydraulic actuators are bulky and hence undesirable when trying to maximise head room and storage within the hull. Depending upon how the actuators are placed, whether it be one unit located to one side of the yacht or two actuators either side of the centre line, working space inside the hull can be unnecessarily wasted as a consequence.

Also, a general premise of yacht design is to keep the centre of gravity as low as possible. The use of bulky and heavy actuation means effectively serves to counteract the latter.

The second disadvantage is the use of a pivot point which is not integral with the hull but rather split into two or more discrete axle or stub-axles. In this instance, an overcompensation of reinforcement is used inside the keel floor structure to compensate for the reduction of stiffness in all dimensions. This can add much unnecessary weight and contribute to the reduction of available space within the hull. Hydraulic cylinders also require significant space to locate

lateral to the longitudinal axis. This can lead to wider hull forms being needed to accommodate the rams.

A third disadvantage arising from implementation of current canting mechanisms is that of safety. The use of hydraulic actuators can delay the return of the ballast structure from a canted position to a standard vertical position. In adverse sailing conditions encountered in open waters, a delayed response of this type can jeopardise the safety of crew and the integrity of the yacht.

A fourth disadvantage of current canting systems is the lack of lateral resistance for the yacht while the ballast is in a canted position. To reduce sideways slip, racing yachts deploy a leeboard-an extra foil section lowered vertically and aligned with the centre line of the hull. When in use, the leeboard provides sufficient lateral compensation to reduce sideways slip and therefore minimise leeway. However, in a typical configuration, the leeboard becomes subject to intense dynamic loading as the yacht powers over and through ocean swell and surface waves as a result of the board extending directly from the hull.

When not deployed, the board must be stored within the hull whereby the effective result is an increase in overall yacht weight.

Accordingly, it is an object of the present invention to provide a ballast system and related means for a yacht which addresses the above mentioned disadvantages of current ballast systems or which will at least provide the public with a useful choice.

BRIEF DESCRIPTION OF THE INVENTION In a first aspect the present invention consists in a canting keel structure of or for a yacht, comprising or including, a fin, vertically split to define two or more fore/aftwardly disposed individual fin portions, a ballast means split into two or more individual ballast portions each engaged or forming part of or dependent from a respective said fin portions,

one or more pivot means to allow canting of said fin portions about a pivot axis extending parallel to the longitudinal axis of said yacht, wherein, in use when fitted to a hull of said yacht, each said fin and ballast portions (as a unit) can be individually canted (preferably at least in part independent from the other of said fin and ballast portions) about said pivot axis by said pivot means.

Preferably said canting is about a pivot axis positioned at the hull skin of the yacht.

Preferably said fin is split to define said individual fin portions about a plane or planes transverse to said fore/aft line of said yacht (e. g. preferably in a port-starboard orientation), to position a first fin portion forward more of the other fin portion (s).

Preferably said ballast means is dependent from said fin and is split about a plane or planes extending in the fore/aft direction and preferably vertically.

Preferably said ballast means is dependent from said fin and is split about a plane or planes which allow separation of said ballast portions and said fin portions in a direction lateral to the fore/aft direction of said yacht.

Preferably each said fin portion includes a ballast portion.

Preferably each said fin portion has disposed at its distal most end away from said hull, a respective ballast portion.

Preferably each said ballast portion is at least in part in a lateral to the fore/aft direction overlap to each other.

Preferably each said ballast portion is at least in part in a lateral (to the fore/aft direction and lateral to the elongate direction of the fin portion) overlap relative to the other of said ballast portions, when such are in abutting relation.

Preferably each said ballast portion is at least in part in a lateral (to the fore/aft direction and lateral to the elongate direction of the fin portion) overlap relative to the other of said ballast portion (s) when said respective fin portions are in a coplanar relationship with each other.

Preferably each said ballast portion is at least in part in a lateral (to the fore/aft direction and parallel to the elongate direction of the fin portion) overlap relative to the other of said ballast portions.

Preferably each said ballast portion is at least in part in a lateral (to the fore/aft direction and parallel to the elongate direction of the fin portion) overlap relative to the other of said ballast portions when said fin portions are in a coplanar relationship with each other.

Preferably each said ballast portion is at least in part in a lateral (to the fore/aft direction and parallel and transverse to the elongate direction of the fin portion) overlap relative to the other of said ballast portions when said fin portions are in a coplanar relationship with each other.

Preferably said overlap allows for a first fin portion to pivot about the pivot axis independent from the other fin portion towards one side only of the other of said fin portions.

Preferably said overlap is such to allow for a first fin portion to pivot about the pivot axis independent from the other fin portion towards one side only of the other of said fin portions, but rotation in the opposite direction results in the other fin portion needing to move in unison with the said fin portion.

Preferably each said fin portion has a corresponding ballast portion attached thereto.

Preferably said fin portions are selectively engageable, one to the other, to in an engaged condition forming a coplanar fin structure.

Preferably said selective engagement is at least by complementary engagement of said fin portions to each other, along at least in part their said split plane.

Preferably said complementary engagement is along the entire said transverse split plane (s).

Preferably said ballast portions are selectively engageable, one to the other to, in said engaged condition, form a singular effective ballast structure.

Preferably when in a coplanar condition, said fin portions can be canted either side of the vertical centreline plane of said yacht by said pivot means.

Preferably at least one of said fin portions can be actuated for pivotal movement about said pivot axis independently of said other fin portion (s).

Preferably all of said fin portions can be pivoted about said pivot axis independently of each said other fin portion (s).

Preferably there are only two fin portions.

Preferably there are only two ballast portions one for each fin portion.

Preferably said complementary engagement to define said coplanar fin structure is enabled by rotation of one, or both fin portion (s) relative to each other about an axis parallel to said fore aft line.

Preferably said complementary engagement to define said coplanar fin structure is enabled by translation of one, or both fin portion (s) relative to each other along an axis parallel to said fore aft line about an axis.

Preferably said axis is the first mentioned axis.

Preferably said pivot means includes an actuator to actuate pivotal movement.

Preferably said rotation occurs about an axle rigidly fixed to said hull.

Preferably said fin portions may also translate relative to each other in a in a fore/aft direction, to move into and out of an overlapping relationship with each other.

Preferably said actuator is contained in said hull.

Preferably said pivot means is disposed within said hull and includes a rack and pinion means, with which said actuator is in operative engagement.

Preferably said pivot means consists of a rack and pinion arrangement for each of said fin portions, wherein for each fin portion one of said rack and pinion is carried by said fin portion and the other of said rack and pinion is carried engaged to said hull, and wherein an actuator is in operative engagement with said pinion to drive said pinion for its movement along said rack.

Preferably wing members are deployable, each independently of each other, from one or each of the end of said fin portions and/or ballast portions.

Preferably said wing members are deployable from a condition whereby they are at least partially contained in the ballast and/or fin portions to a fully deployed condition.

Preferably there are two such wing members.

Preferably one each of said wing members is deployable from one each of said ballast portions.

Preferably said wing members are deployable one each from an opposite side of the longitudinal direction of its respective fin member relative to the other wing member and deployable from the other.

Preferably said keel structure includes wing members as hereinafter described.

Preferably the stern most fin portion includes a trim tab extending at least along part of the trailing edge of the stern most fin portion and pivotable about a pivot axis in plane with the chord of the stern most fin portion.

Preferably the forward most fin portion includes a trim tab disposed to its leading edge and extending at least along part thereof, and being pivotable to the forward most fin portion about an axis parallel to the chord of the forward most fin portion.

In a second aspect the present invention consists in a canting appendage structure of or for a hull comprising or including: a fin depending from said hull pivotable at or proximate its hull proximal end about an axis parallel to the fore/aft plan of said hull, said fin comprising at least two separate fin portions each independently pivotable about said axis and capable of alignment to assume a coplanar configuration, an actuation means for each of said fin portions to effect said pivot, wherein said fin portions can be canted together as a single unit when in said coplanar configuration or individually to both sides of said hull centre line by said actuation means.

Preferably said canting appendage structure also includes a ballast means split (preferably longitudinally) into two separate (preferably port and starboard more) ballast portions, one each associated with one of said fin portions.

Preferably at least one fin portion includes a ballast means.

Preferably all fin portions include a ballast means.

Preferably said ballast means is split longitudinally about a vertical plane.

Preferably said actuation means are interior of said hull and act on said fin portions also extending in part interior of said hull, and to the opposite side of said axis of rotation to the exterior to the hull portion of said fin portion.

Preferably each said actuation means is a hydraulically actuated pinion gear which is affixed to a said fin portion, each pinion gear in meshing engagement with a rack affixed to said hull.

Preferably said fin portions each pivot about an axle member longitudinally mounted in said hull.

Preferably said ballast means is part of said fin.

Preferably said ballast means is incorporated in said fin.

Preferably wherein said ballast means is attached to the end of the fin.

Preferably said axle member is rigidly fixed to said hull, imparting increased stiffness and strength to said hull.

Preferably said rack is shaped to track the movement of said pinion gear about said pivot axle.

Preferably said rack shape is substantially arcuate.

Preferably said actuation means is as herein after described.

Preferably said rack imparts rigidity to said hull in at least a transverse direction.

Preferably said fin portions are fore and aft more disposed fin portions and selectively engageable along transverse to the longitudinal fore/aft direction mating surfaces, to assume the coplanar single unit condition.

Preferably said fin portions are engaged by at least one locking means disposed at mating surfaces of said fin portions.

Preferably one or each said fin portions can translate in said fore/aft direction (preferably along said axle member) to engage or disengage from one another in and out of said complimentary engagement.

Preferably said translation may be parallel to, but not co-axial with said axis, but rather is along a separate tracking means, intermediate of said first mentioned axis and said fin structure.

Preferably said translation is actuable by hydraulic actuators (preferably hydraulic rams).

Preferably said ballast portions are selectively engagable along said longitudinal split.

Preferably said ballast portion selective engagement is by at least one means engageable between each ballast portion, whether as a result of said translation or by independent actuable means.

Preferably said fin, whether independent and/or together, can be canted between the vertical (0°) to the horizontal (90°) either side of said hull longitudinal vertical plane.

Preferably said canting is in the range of from 0° to 60°.

Preferably said longitudinal direction runs fore and aft along said hull.

Preferably said transverse direction runs from port to starboard across said hull.

Preferably said actuation means includes of a pinion gear, attached to or proximal to said hull proximal end of each said fin, trackable in a corresponding rack attached to said hull.

Preferably there are wing members deployable from said appendage structure.

Preferably each ballast portion has a wing member pivotally deployable therefrom.

Preferably deployment of each said wing fin member is independently controllable.

Preferably said deployment is by hydraulic means.

Preferably said axle member is integral with said hull to stiffen and strengthen said hull.

Preferably each of said fin portions and associated ballast portions can be actuated hydraulically or can be actuated by gravity independently.

Preferably said appendage structure is a keel structure.

Preferably said appendage structure is a non righting moment affecting foil structure.

Preferably said appendage structure includes wing member as hereinafter described.

Preferably said appendage structure includes a canting mechanism as hereinafter described.

Preferably said appendage structure includes an axial translation means for said fin portion or portions as hereinafter described.

Preferably the stern most fin portion includes a trim tab extending at least along part of the trailing edge of the stern most fin portion and pivotable about a pivot axis in plane with the chord of the stern most fin portion.

Preferably the forward most fin portion includes a trim tab disposed to its leading edge and extending at least along part thereof, and being pivotable to the forward most fin portion about an axis parallel to the chord of the forward most fin portion.

In a further aspect the present invention consists in a wing member of or for a keel (preferably canting keel) structure located at a position at or near the hull distal most region of a keel structure, said wind member being deployable and from a retracted within a cavity of said keel position to a position where it extends from said keel, to provide increased hydrodynamic lateral resistance to counteract the reduced lateral resistance experienced by a canted keel or keel (s).

Preferably there are two such wing members, one each side of the centreline plane of said keel structure.

Preferably said wing member (s) are deployable from a ballast bulb of said keel structure which is disposed at the distal end of a fin of said keel structure.

Preferably said wing member (s) can be at least partially contained in and deployed from said ballast member of said keel structure.

Preferably said wing member (s) can be deployed independently of one another.

Preferably either or both of said wing member (s) are movable (preferably by rotation) to be inclined to the incident water flow to increase the lift of the keel structure.

Preferably the angle of incidence of said wing member (s) to said incident water flow is adjustable.

Preferably said wing member (s) are inclined to the incident flow by between +5 and-5 degrees.

Preferably said wing member (s) both are inclined negatively to the incident water flow to increase lateral resistance.

Preferably the wing member (s) are inclined at-3 degrees to the incident water flow.

Preferably the wing member (s) is incorporated in a canting keel structure as hereinbefore described.

In a further aspect the present invention consists in a canting keel incorporating a wing member or members as herein described with reference to the accompanying drawings.

Preferably the canting keel includes a fin portion which includes a trim tab extending at least along part of the trailing edge of the fin portion and rotatable relative to the fin portion about an axis in plane with the chord of the fin portion.

Preferably the fin portion also includes a trim tab disposed along at least part of the leading edge of the fin portion and is pivotable relative thereto about a pivot axis in plane with the chord of the fin portion.

In a further aspect the present invention consist in a hull of a yacht which incorporates a canting keel having a wing or wing members as hereinbefore described.

In a further aspect the present invention consists in a means for canting a keel appendage of a yacht of a kind which includes a foil extending from a pivot axis parallel with the fore/aft vertical plane of said yacht to the exterior side of the hull of said yacht and a lever arm interior of said hull acting on (and preferably forming part of) said foil, said means comprising, (a) a rack, fastened to said hull (b) a pinion, attached lever arm and operatively engaged with said rack (c) a prime mover to actuate relative movement of said rack and said pinion.

Preferably said prime mover drives said pinion rotationally to displace it along said rack to induce cant on said keel appendage about said pivot axis preferably defined by an axle member fastened to said hull.

Preferably said rack is curved over the locus of movement of said pinion.

Preferably said curve is equidistant from said axle member.

Preferably said pinion is driven hydraulically by said prime mover.

Preferably said rack is lateral to the fore/aft direction of said hull.

Preferably said pinion is driven through a planetary gear box or equivalent torque stepping means.

Preferably said keel appendage is split into two or more canting keel appendages as herein before described there is at least one such means for canting associated with each of the interior portions of said canting keel appendages.

Preferably there is a means to lock each of said canting keel appendages to each other. Such locking to each other may be a locking pin passing from one keel appendage to the other.

Preferably there is means to lock one or each keel appendage to said hull at any particular angle of cant.

Preferably said keel appendage is of a kind as hereinbefore described.

In a further aspect the present invention consists in a keel appendage, comprising or including, a first forward more keel appendage portion a second rearward more keel appendage portion, each keel appendage portion mounted at least translationally on a common translation slide, or axle member, a prime mover acting on one or both of said first and second portions, wherein said prime mover is in operative engagement with at least on of said keel appendage portions to cause translational movement of said portion relative to said axle member.

Preferably each said of said portions has said means for axial translation.

Preferably said means for translation is used to displace at least one of said keel appendage portion being incorporated, as one of the fin portions in a keel or appendage structure as hereinbefore described.

In a further aspect the present invention consists in a keel assembly for a boat hull or a boat hull including a keel assembly, the assembly being deployed or deployable to define a hull centred keel with a centred ballast means, wherein the keel is portionable so as to allow one portion to cant in one direction from the centre and another portion to cant in the other direction from the centre, or from the first mentioned portion, and wherein each portion of the keel portions can carry with it a portioned part of the ballast means.

Preferably the keel assembly may preferably also include the trailing edge trim tab or leading edge trim tabs as herein described.

Preferably the portioning is of the keel is not in a plane on which the keel can be centred but rather on either side of a separation to allow portioning transverse of the main hull axis.

Preferably said centred ballast means is a bulb structure depending from said hull centred keel.

In a further aspect the present invention consists in a canting keel as herein described with reference to one or more of the accompanying drawings.

In a further aspect the present invention consists in a method of trimming a yacht by canting a keel of a kind as hereinbefore defined.

In another aspect the present invention consists in a method of mooring a yacht by splitting the fins of a keel as hereinbefore defined by each fin being rotated to opposite sides of the centre line of said yacht.

Preferably said rotation to opposite sides of the centre line reduces the draft of the yacht.

In another aspect still the present invention consists in an apparatus to provide a cantable keel, draft reduction and retractable fins for operative association with a hull and components to provide a canting keel as herein described with reference to the accompanying drawings In another aspect the present invention consists in a hull including a canting keel as hereinbefore described.

In yet another aspect the present invention consists in a yacht including a canting keel as hereinbefore described.

In yet a further aspect the present invention consists in a canting keel of or part of a yacht comprising: a) a main foil portion pivotally engaged with the hull of a vessel in order to allow it to cant about a generally fore/aft aligned pivot axis, b) optionally a ballast means disposed to the end of the foil portion distal most from the hull, c) at least one trim tab disposed in a location selected from (i) the leading edge of said foil and (ii) the trailing edge of said foil, d) said trim tab extending along at least part of the foil and pivotable relative to the foil about an axis in plane with the chord of the foil.

Preferably there are disposed two trim tabs to the foil one on the leading edge of the foil and one on the trailing edge of the foil.

In still a further aspect, the present the invention consists in a means for canting a keel appendage of a yacht of a kind which includes a foil extending from a pivot axis parallel with the fore/aft vertical plane of said yacht to the exterior side of the hull of said yacht and a lever arm interior of said hull acting on (and preferably forming part of) said foil, said means comprising, (a) a pinion fastened to said hull (b) a rack, attached lever arm and operatively engaged with said rack (c) a prime mover to actuate relative movement of said rack and said pinion.

BRIEF DESCRIPTION OF THE DRAWINGS With reference to the accompanying drawings preferred embodiments of the present invention are described whereby Figure 1 shows the force system that a yacht is typically subject to when going upwind (close-hauled), from bow on.

Figure 2 shows a bow on schematic of the canting keel arrangement in relation to the hull and the draft reduction can be gained by canting, Figure 3A shows a front view of the keel canted with wing fins deployed.

Figure 3B shows a plan view of the keel.

Figure 4A is a side elevation of the keel structure with the keel and ballast portions locked together, Figure 4B is a transverse section view of a prior art yacht which shows hydraulic rams acting on the keel to cant it and as a consequence of needing to take into consideration the throw of such rams, the width of a canting mechanism unit is wider than the travel of the end of the foil where the rams are attached, Figure 5 is a front and or rear view of the keel structure with the keel and ballast portions locked together, Figure 6 is a similar view to that of Figures 1-3 in an isometric view, Figure 7 is an isometric view of the keel fin members split apart along a transverse line with accompanying ballast portions split along a longitudinal line,

Figure 8 is an end view of that Figure 5, Figure 9 is a side view of the split keel and ballast portions, Figure 10 is a side view of the keel fin and ballast structure showing the faring amount into the hull of a boat, Figure 11 is a sectional view on a vertical plane showing the mounting of a keel fin structure on the pivot point, the means for translation and also the actuation means interior of the hull, Figure 12A and 12B show a close up of the pivot bearing assembly in cross-section for pivoting of the fin sections in a canting member a) from above in cross-section and b) from above, Figure 13A and 13B show a close up of the attachment and fastening arrangement of the pivot arrangement a) together with a cross-sectional view b) through the vertical plane, Figure 14 shows in isometric an embodiment whereby there is no ballast member, but rather the ballast is all in the fin structure, Figure 15 shows a fins structure of Figure 14, with ballast mean attached and showing an alternative fin split arrangement, Figure 16 shows a view down the axis of one of the wing fins showing the angle of incidence to the flow of water, Figure 17 is a similar view to that of Figure 14 but with a more hydrodynamic profile on the leading edge of the downstream fin section, Figure 18 is a similar view to that of Figure 15 again with a more hydrodynamic profile of the downstream fin leading edge, Figure 19A and 19B show the deployment of a wing from, in this particular case, the ballast of the keel structure, in a) and also in b) a view from the perspective indicated in a) of the angle of incidence of the wing to the incident water flow, Figure 20 shows from a bow on perspective a canting fin structure with ballast means and also a separate canting fin or leeboard system,

Figure 21 is a similar view to that of Figure 21 with the exception that the boat is heeled over, the fin with ballast means is canted out to provide a greater righting moment and the centre fin or leeboard is canted vertically to give the greatest lateral resistant possible, Figure 22A and 22B show a ballast and fin arrangement that may be applicable to the system shown Figures 21 and 22 in that the leading edge (in this example) has attached to it a ballast means and the trailing edge has no depending ballast means attached, Figure 23 shows a further embodiment of that shown in Figures 22a and b, Figure 24A and 24B show a further embodiment of that shown in Figure 23 with the exception of having no ballast means separately depending from either of the fins, Figure 25 shows a side elevation of the keel structure and ballast portions locked together and incorporating a rotatable trim tab located along the aft trailing edge of the rear keel portion, Figure 26 shows a side elevation of the keel structure and ballast portions locked together with a movable or rotatable leading edge located along the forward edge of the front keel portion, and Figure 27 shows a side elevation of the keel structure with keel and ballast portions locked together and incorporating both a rear trailing edge trim tab located along the rear keel portion as well as a movable rotatable leading edge trim tab located along the forward portion of the front keel section.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figures 1 through 27 there is shown a canting keel or appendage system in accordance with the present invention.

Yachts will typically have a keel structure mounted from their hull 1 below the waterline consisting of a fin 3 and also optionally, a form of ballast 9.

Above the hull extends the rig, including the mast, rigging and sail (s). For some

yachts, the ballast 9 may be incorporated within the fin but it is becoming more common especially for high performance yachts for the ballast to be provided as a bulb to be attached to the end of the fin away from the hull.

The wind on the rig and sails creates a force component FH, acting through the Centre of Pressure, perpendicular to the fore-aft plane of the hull. This force, multiplied by the distance of the Centre of Pressure from the Centre of Mass of the boat, produces the heeling moment on the boat, and thus the angle of heel on the boat a from the vertical. If such a heeling moment is not opposed by a keel structure or other form of ballast, then the boat will heel over until all apparent wind force is removed from the sails (i. e. the sails being no longer effective).

The purpose of the keel structure, and particularly the ballast 9 present, is to provide additional righting moment compared to a fixed keel to counter the heeling moment created. This allows the hull to achieve an efficient, upright as possible, sailing position.

By concentrating the ballast weight as far below the boat as possible (such as when the ballast 9 is suspended from the long fin or foil 3), greater righting moments are possible. A righting force FB, is achieved for a given keel structure depth. Further advantage can be gained by such a keel structure if it can be canted out of the heel plane 23 of the boat, by an angle 0 towards either the port or starboard side, being the windward side 39 when sailing. Such canting increases the effective lever arm of the ballast and thus increases the righting moment for a given ballast weight, thus resulting in a more upright sailing configuration.

The present invention has the fin 3 and optional ballast 9 canting about an axle 41. The axle 41, in the preferred embodiment, is a single continuous member that is engaged and affixed with the hull 3. Such engagement may be by a spline, square or other polygonal, interference fit, clamping or otherwise form engagement with the hull structure and may also be achieved via bolting and fastening (whether by clamping means or otherwise) engagement to the hull.

The preferred form of engagement is at the fore and aft end of the axle 41, but

may be alternatively or in addition intermediate of either end also. Such integration with the hull of the boat alleviates the reduced torsional and bending stiffness and strength that is created by an aperture in the hull necessary for a canting keel.

A fin interior portion 43 is located in the interior 45 of the yacht and is preferably located below the cabin sole plate 59. The fin interior portion 43 has at or near its end a powered or driven pinion 31 which is engageable with a rack 29. Due to the rotation of the fin interior portion end 43 and the pinion 31 about the pivot axle 39 and axle 41, the shape traced by the pinion 31 is a circular arc over the locus of movement of the pinion, corresponding to the full of cant required. The fin interior portion is effectively a lever acting on the fin exterior portion about a fulcrum defined by the axle 41. The rack may be a concave side or convex disposed side. The pinion 31 in the preferred embodiment is powered by a hydraulic motor powered from a remote source such as a hydraulic pump or accumulator or other form of prime mover. The pinion is attached to a gear box 32 to step the torque up to the required value to cant the structure. Other methods may also be used to power the pinion such as electrical or mechanical means and all are consistent with the scope of this invention.

The hull 1 has an interior 45 and an exterior 47 of which part is in the water and part is above the water. The interior has a cabin sole plate 59 which, for all intents and purposes is the bottom of the cabin, and together with the hull roof 61, forms the interior liveable space of the yacht. The use of a rack 29 and pinion 31 as herein described for canting single foil appendage/keel or the split foil keel as herein described, gives rise to minimal or reduced intrusion (that is actuating mechanism height 97 and width 99) of the actuating means into the hull interior 45. The transverse mounted rack and pinion system provides the smallest possible footprint beam 99, and height 97, in the boat thus allowing the beam to be reduced to give speed improvements. Reducing this footprint envelope allows lowering the cabin sole 59 to give improved interior head room as well as lowering both the mass and its location in the boat. The advantage that

a rack and pinion mechanism also brings is the fact that the force on the interior portion of the fin (the lever arm) is applied by the rack and pinion at a tangent to the axis of rotation (preferably normal to the elongate direction of the fin).

Due to the mobile nature of the fin rotation about the axle 41 and the fact that such keel arrangement is below the water line, there is a requirement for sealing about the fin 3 where it enters the hull 1. Such sealing may be achieved by use of a hull gland 65 which seals around the fin where it enters the hull and prevents, or substantially reduces, the entrance of water into the hull interior 45.

Another method of sealing off the area is by use of a wet box 63. Such a box, while at least substantially sealed by use of a hull gland 65, is completely water tight at its periphery from the interior of the boat 45. Therefore any entrance of water into the area defined by the wet box 63 is contained entirely within the wet box and for all intents and purposes seals the exterior part of the hull from the interior. For servicing and maintenance requirements such a box may be pumped dry. The boat may also be lifted from the water where servicing on the rack 29, pinion 31, axle 41 and other components may be affected.

A component of the resultant force acting through the rig centre of pressure is a horizontal force FS on the boat. This force component pushes the boat away from the wind. Thus the boat does not travel a line consistent with its fore to aft line but rather bears away or has"sideways slip" (also known as leeway) from such a line as it"skids"away from the wind.

To oppose such"sideways slip", and thus reduce leeway, the fin 3 together with a trim tab (not shown but well known in the art) on the trailing edge of the fin 3 provides a hydrodynamic lift force FF. This is achieved by trimming the tab towards the leeward side creating a wing section having a high pressure region to leeward and a low pressure region to windward 39. The horizontal component FT of this lift force, at least in part, opposes the horizontal force FS, reducing the leeway of the boat.

As the fin 3 (and ballast 9) is canted over to windward the effective leeway resisting area of the fin is reduced. This reduces the hydrodynamic lift

force FF such a keel fin can provide. Thus in a significantly canted condition (60 degrees or more from the vertical centreline of the yacht) there is close to no horizontal force Fs given by the keel fin 3 itself.

It is desirable therefore to continue to counteract this force by the deployment of at least one wing member 33. In the preferred embodiment such deployment is one each from the ballast portion or portions 11 and 13.

Optionally, however, the deployment may be from the or a fin portion, even in the optional presence of a ballast 9 such as a keel bulb.

In the preferred embodiment the wing members 33 are at least in part and preferably substantially contained within the ballast 9 though may have a small portion thereof extending outside of the ballast 9. The wing members 33 are preferably mounted horizontally when the keel is at a vertical orientation (i. e. at zero cant angle A and zero heel angle a). The wing members can be increasingly deployed to provide more lateral resistance force to reduce the leeway of the boat. The angle of deployment can be linked directly to the combined angle of heel and cant, or may be manually set as the captain of the boat requires. At full cant, the wing (s) is/are preferably fully deployed to give maximum lateral resistance, by virtue of the resultant lift force generated L. The lift force L opposes the lateral force from the wind loading which pushes the boat away from the wind.

The angle of incidence to the apparent water flow across the wing members 33 can be adjusted also. Thus the optimum balance of drag induced by incidence to the water and lift created by that incidence can be met. The wing members 33 have at least two degrees of freedom, one being the angle of deployment from the keel structure and or ballast 9 (preferably by pivoting), and the second being the angle of incidence of the wing member 33 and the incident water flow. The wings 33 may either have a semi-permanently fixed angle of incidence, such as that achieved when fixed to a splined shaft aligned perpendicular to the wing chord. Alternatively the wings 33 may be actuable to

change their angle of incidence while in motion to the water flow such as by hydraulic, mechanical or other means.

To increase the lateral resistance afforded by the wing member 33 the preferred embodiment has an incident angle 57 which in use is negative in relation to the incident water flow. Such a negative angle will create on the leeward side of the wing member a high pressure region and on the windward side of the wing member 33 a low pressure region. The resultant force will be additional to that created by the keel fin and trim tab combination in that it will oppose the lateral force created by the wind and thus reduce the"skidding"of the boat.

The wings 33 can be actuable for deployment and/or angle of incidence either independently of each other or actuated together from a common actuation mechanism. In the preferred embodiment, the wings 33 are actuated or actuable independently by a hydraulic mechanism. The actuation mechanism for the wings 33 may be located in the keel structure, such as in the fin 3. In the preferred embodiment, the actuation mechanism for wings 33 may be located in the ballast 9 to locate the weight lower down. Alternatively, there may be an actuation mechanism located in the interior of the hull and hydraulic lines running down to the hydraulic motors to actuate the wings 33. Other possible means of actuation are also within the scope of this invention such as, for example, electronic, mechanical, or other methods of creating a rotary motion that are known in the art to affect the two degrees of freedom.

The wings 33 may be further angled down from their mounting position in the keel structure or ballast 9 to be as vertically aligned as possible, in all canting situations of the keel structure, thus giving maximum lateral resistance at all times.

Such a wing member, because it is deployable only in those situations where increased lateral resistance is required, provides reduced drag when not required due to its folding nature within either the ballast 9 or fin structure. The wings 33 are predominantly below the water line and therefore incur less

dynamic loading than on an equivalent leeboard structure (which may often leave the water and then'slam'back into the water creating high dynamic shock loading). Since the wings 33 are not as dynamically loaded as a leeboard structure, it can be made lighter due to lower strength requirements.

Furthermore, since the wings 33 is/are contained within the ballast 0 the additional weight associated with it is located as low as possible, and thus assists in lowering the centre of gravity of the boat.

In use it is the lower most wing that is deployed, the upper most being retracted. This may however be vice versa.

The keel structure consisting of the fin 3, and in the preferred embodiment ballast 9 (and optionally the wing members 33), should, to give the best effect to the canting arrangement, be as long or as deep as possible, i. e have a substantial draft. Such a deep draft poses problems when navigating or mooring in shallow waters such as, for example, when under motor or when sailing close to shore or in shallow regions and harbours.

When under motor the canting of the entire keel out to one side will result in an undesirable and possibly even dangerous heeling of the boat. Therefore, the fin 3 of the present invention is split into two fin portions 5 and 7. Each fin portion may have a corresponding ballast portion 11 and 13 respectively. In the preferred embodiment, a cant of 60 degrees from the vertical can result in a 25% reduction in effective draft for the keel structure.

In the preferred embodiment, the fin is split vertically along a plane or planes transverse to the fore aft line (i. e. parallel to the port starboard line) of the boat. The ballast 9 is correspondingly split preferably in a vertical plane parallel to the fore aft line of the boat. In the preferred embodiment of the split of the keel fin, the trailing edge of the leading keel fin portion 5 has a concave or otherwise form. The leading edge of the trailing fin portion 7 has a convex 8 or otherwise hydrodynamically shaped form to reduce the drag on the fin structure when canted separately. The convex 8 and concave 6 or otherwise shapes are complimentary to engage with one another along the transverse split. Thus,

when the trailing edge and/or the leading edge of the two fin portions are collinear they can be engaged along their complimentary profile (created for example by the convex/concave shaping) by a translational movement of either or both the leading and trailing fin portions relative to each other and/or the hull.

Such engagement lends further rigidity to the keel fin structure when operating as a singular coplanar unit.

Such a transverse split in the keel fin is preferable as it has advantages over longitudinal fin splits of the prior art. Namely, for a given keel fin cross section, a transverse split will impart a greater sectional modulus in relation to bending when compared to the relatively slender section that will result from a longitudinal keel fin split. This imparts advantages when the keel fin is canted as a unitary structure and also when each fin portion is canted individually to reduce draft.

Further engagement means may be present at such an interface such as hooks that protrude out and engage with some form of complimentary eyelet or similar. There may also be a rod or elongate member which is passed down the keel fin at the interface location to engage eyelets or similar structures protruding from or within the keel fin portions to further rigidly engage the leading and trailing fin portions.

Further engagement means may also be present at the interface of the ballast portions 11 and 13. These may be passive forms engage when the translation of the two structures is actuated or they may be active forms similar to those along the keel fin portion interface. Such locking means for both the keel fin and/or the ballast 9 may be actuated hydraulically, mechanically, electrically (including magnetic) or by other means known in the art.

The transverse split of the keel fin together with the longitudinal split of the ballast 9 results in a structure that has increased resilience to twisting about the vertical axis. This in turn gives increased rigidity to the resulting structure to resist hydrodynamic forces and assists the boat in achieving the direction desired.

The translation of the fore fin portion 5 relative to the aft fin portion in relation to the aft fin portion 7 is achieved by movement of the casing 71 about or along the axle 41. The axle 41 has a piston portion 93 which is sealed about its periphery by a piston seal 85. The piston portion 93 divides the interior into two hydraulic cavities 91, axially either side of the piston portion 93. Hydraulic supply/return lines 79 feed each hydraulic cavity 91; one being a hydraulic fluid under pressure supply line, the other being a hydraulic return line draining the cavity when translation is one way, and vice versa when translation is the other way. The supply of hydraulic pressure via the line 79 into one cavity, urges that supplied cavity to expand. Since there is an ability to translate axially, and the axle 41 (and hence the piston portion 93) is fixed rigidly, then the expansion of the cavity under pressure will cause the fin portion 7 to move to the right, if for example cavity B is supplied with fluid pressure. Cavity B in this case is allowed to drain via its supply line as the cavity decreases in volume. Corresponding fluid pressure supplied to cavity A, and drainage allowed from cavity B will cause translation of fin portion 7 to the left of Figure 11.

The resulting pressure application will result in translation of the casings 71 relative to each other and thus will result in an axial translation of the aft fin region 7 in relation to the fore fin region 5. Such translation may be only of the aft fin region, or only of the fore fin portion 7 or may be both portions 5 and 7 relative to one another. Such translation is only required to be sufficient to disengage the complimentary engaging profile at the fore and aft fin interface.

Once such complimentary disengagement is disengaged from itself, the fin portions are free to be canted either individually or together under the actuation of the rack 29 and pinion 31 actuation mechanism. There is allowance, fore and aft on the rack and pinion actuation mechanism, sufficient for any translation to not disengage the pinion from the rack. Such as, for example, the rack and/or the pinion may be sufficiently wide enough, so that even when there is full translation of either one direction or the other, the pinion is still engaged with the rack. In Figure 11, in respect of the translation mechanism, there is shown a rack

and pinion canting mechanism. This alternative means of effecting cant may be employed as herein described. The rack and pinion mechanism is of compact width to allow narrower hull forms.

The casing 71 is split horizontally into two or more corresponding clam shells and held together about the axle 41 by bolt 95 or similar means. This enables the easy removal of the below water keel structure for servicing, maintenance and or replacement. Such a clam shell configuration allows the axle 41 to be integral with the hull to achieve the above mentioned strength and stiffness improvements. The below water appendages and wings, when powered hydraulically, require the supply of hydraulic fluid from the hull and to the appendages. One such method is the inclusion of matching galleries between the two clam shell sections, so that when attached about the axle 41 a number of continuous supply and return lines for each appendage actuation would be required (e. g. for two degrees of freedom on each of two appendages, 4 supply return pairs, or 8 galleries) would be required. The inboard portion of the casing will have hydraulic lines attached to supply each gallery. Below the water line, galleries may run all the way to each appendage or like hydraulic lines may run to the actuators for each appendage.

Alternative to the translation of the casings 71 along the axle 41, there may be translation means intermediate of the casings 71 and the majority of the fins. Such translation means may be a sliding mating pathway or similar which is powered to achieve the translation. The alternative means may be on one or both of each fore 5 and aft 7 fins portions.

Generally, when sailing, the keel fin, as a unitary structure of both the fore and aft fin portions 5 and 7 and optional ballast portions 11 and 13, is canted as a singular structure to either port or starboard direction as is required. Typically, this direction is towards the windward side when sailing upwind.

When a reduction in draft is required, the fore and aft fin portions 5 and 7 may be disengaged from one another (by disengagement of the complimentary engagement and/or locking means) and translated, in a manner described above,

under the influence of the actuation mechanism (being the rack and pinion 29 and 31). Both fore and aft fin portions are canted away from the centre line to the port and starboard side respectively. In the dimensions of the preferred embodiment, a 60 degree canting angle will result in a reduction of draft by up to 1.5 metres for a keel structure that draws 6 metres. The canting of each individual fin structure out to the side will not adversely increase the overall beam of the boat. Thus a keel structure that would normally draw six metres in an uncanted configuration may be reduced to a 4.5 metre draft.

A safety feature is also incorporated in the event the boat should heel over too far due to sea state or wind conditions. In this event, either by automatic or manual intervention, the actuation mechanism may be disengaged (either by disengagement of the rack from the pinion or by removal of hydraulic pressure or mechanical means to the pinion) thus allowing the keel fin portions to fall back to a mid ship position under the action of gravity. Such action under gravity, with removal of the actuation force, is quick and safe and faster than with the use of a hydraulic ram where the fluid must be forced back through the system.

Further advantages are conveyed by the present invention in that the full advantage of a deep draft canting keel structure can be utilised while also reducing the draft for operating in shallow waters.

A further embodiment of the present invention is shown in Figures 20 through 24. This involves a keel fin 3 split into two canting fin portions, a fore fin portion 5 and an aft fin portion 7. The fore fin portion 5 has a ballast 9 extending from its distal end. Whilst the aft fin portion 7 has no significant ballast 9 relative to that extending from the fore fin portion 5. The fin portion carrying the ballast 9 can be canted out to windward. The righting moment needs to be increased while the relatively non ballasted fin portion 7 can be canted in such a manner so as to give maximum lateral resistance to the boat. Such a relatively non ballasted fin will take the place of or act as a lee board system.

Various configurations are possible such as a full bulb structure 9 attached to the fore fin, as discussed, with a relatively non ballasted rear fin. The ballast 9 can

be a full ballast means or a partially truncated ballast means attached to the fore fin. Alternatively the ballast may be concentrated in a non bulb structure such as shown in Figure 24 and may be concentrated for example in the fore fin 5 whilst the aft fin 7 is used as a lee board structure. In any of the above embodiments the ballast 9 may equally be on the rear fin as the fore fin and the fore fin may be the cantable centre board structure 7.

In an alternative embodiment of the current invention is shown in Figures 25 through 27 describing the addition of a plurality of control surfaces which may be appended to the configuration of the current invention to alter and enhance the lift characteristics of the foil support structure. Figure 25 provides for a movable or rotatable trailing edge section known in the art as a trim tab. As shown in Figure 25, section AA illustrates the degree of freedom obtained by the trim tab in being able to rotate toward either side of the chord line of the foil. As is known in the industry, the advantages of this are to improve the lift characteristics on one side of the foil as opposed to the other. Whilst the structure is canted to one side of the boat, the trim tab may be rotated upward so that increased lift is generated on the underside of the foil structure. This therefore enhances lift production which effectively increases the righting moment of the yacht. Figure 26 illustrates another method of increasing or enhancing the lift characteristics of a standard foil section. In this depiction, a movable or rotatable leading edge is appended to the leading edge of the front foil structure. This assists in altering the angle of attack of the onset flow and provides for enhanced lift across one side of the foil section surface. In a standard mode of operation, the leading edge trim tab will be rotated in such a position that increased lift will be generated across the underside surface of the foil such that the righting moment of the yacht may be increased. The advantages of such an appendage can allow the crew to optimise the effective righting moment of the yacht depending on the yachts heading in relation to the wind and sea way (leeway angle).

A further configuration and enhancement of the latter two ideas may be presented in Figure 27 in which trailing and leading edge trim tabs have been configured in combination with the current invention to provide further degrees of freedom to optimise the trim of the foil structure. Essentially, the addition of both trim tabs can allow the crew of the yacht to customise the performance and lift enhancing characteristics of the foil. Further, it may also be appreciated that the addition and provision for trailing and leading edge trim tabs may also be applicable to the current invention and associated embodiments as described through Figures 17 through 18 and 20 through 24. The configurations presented in these figures and associated descriptions may be modified or appended to incorporate the latter innovations.




 
Previous Patent: FIN PLUG

Next Patent: PERSONAL FLOATATION DEVICE