CA1062091A - Under-water appendages for vessels - Google Patents
Under-water appendages for vesselsInfo
- Publication number
- CA1062091A CA1062091A CA274,202A CA274202A CA1062091A CA 1062091 A CA1062091 A CA 1062091A CA 274202 A CA274202 A CA 274202A CA 1062091 A CA1062091 A CA 1062091A
- Authority
- CA
- Canada
- Prior art keywords
- assembly
- casing
- hydrofoil
- supporting body
- leading
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B3/00—Hulls characterised by their structure or component parts
- B63B3/14—Hull parts
- B63B3/38—Keels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
- B63B39/06—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using foils acting on ambient water
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H25/00—Steering; Slowing-down otherwise than by use of propulsive elements; Dynamic anchoring, i.e. positioning vessels by means of main or auxiliary propulsive elements
- B63H25/06—Steering by rudders
- B63H25/38—Rudders
- B63H25/382—Rudders movable otherwise than for steering purposes; Changing geometry
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
- B63B2035/009—Wind propelled vessels comprising arrangements, installations or devices specially adapted therefor, other than wind propulsion arrangements, installations, or devices, such as sails, running rigging, or the like, and other than sailboards or the like or related equipment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
- B63B39/06—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using foils acting on ambient water
- B63B2039/063—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using foils acting on ambient water the foils comprising flexible portions
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Toys (AREA)
- Prostheses (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A keel assembly or similar fin-like underwater appendage for a boat is provided which is adjustable to adapt it characteristics to the operating conditions of the boat, for example to optimize hull performance of a sailing boat on opposite tacks. The assembly comprises a support and a pair of curved flexible side plates carried by the support and connected at their leading and trailing edges, the curvature of the side plates being adjustable to render the assembly asymmetrical. The leading and trailing portions of the plates are provided by blade assemblies interconnected so as to be oppositely pivotable about axes parallel to leading and trailing edges of the support, the trailing blade assembly having its pivoted axis adjacent its leading edge.
A keel assembly or similar fin-like underwater appendage for a boat is provided which is adjustable to adapt it characteristics to the operating conditions of the boat, for example to optimize hull performance of a sailing boat on opposite tacks. The assembly comprises a support and a pair of curved flexible side plates carried by the support and connected at their leading and trailing edges, the curvature of the side plates being adjustable to render the assembly asymmetrical. The leading and trailing portions of the plates are provided by blade assemblies interconnected so as to be oppositely pivotable about axes parallel to leading and trailing edges of the support, the trailing blade assembly having its pivoted axis adjacent its leading edge.
Description
091 :-.
', THIS INVENTION relates to undërwater appendages particularly such appendages adapted to derive a lift from forward passage through the water.
Many vessels of different types employ underwater lift devices in various circumstances and generally in the form of a fin. ~or example, most vessels are steered by means of a rudder which provides selectively a lift ~-to one side or the other to change the course of the vessel. Other vessels, particularly large commercial vessels, employ stabiliser fins at each side of the vessel, each adapted to apply either for lift in a~ upward or downward dire¢tio~, whichever is the reverse of the op~osite stabiliser fin~ to reduce the rolling of the vessel, and sailing vessels are provided with a keel .
~5 assembl~ to enable them to tack to wi~dward.
~he present invention aims to provide an improved - underwater appendage which may be utilised in the above-mentioned and other applications. ~or illustrative purposes, ,, ",...
the present specification will hereinafter describe the application of the invention to the fin keel assembly of a sailing vessel.
As is well known, sailing boats advance to windward in a zig-zag path because it is not possible to sail directly into the wind. Thus, it is an advantage for a sailing craft to be able to point high into the wind inorder to minimise the distance sailéd to windward.
Apart from the effect of the sails, the ability of a vessel to sail to windward is partly determined by the hull shape and in particular by the shape of the ~eel .. .
~.
- 106~91 assembly which acts to prevent sideway movement of the boat relative to its straight-ahead direction.
As the vessel has to travel in a zig-zag direction, it is of course necessary for the vessel to be able to point high into the wind on both the port and starboard tack and this condition has resulted in most sailing boats having a centrally-disposed symmetrical fin keel. The section most often chosen is a streamlined symmetrical hydrofoil section, preferably with a high aspect ratio. `
While there have been attempts to provide vessels with laterally spaced asymmetrical keels which may be lowered independently according to the tack the vessel is on, such attempts have not been particularly successful because of their complexity and their need for constant tending and be-cause on other points of sailing, they are not as efficient as the central fin keel arrangement.
Accordingly, it is an object of the present invention to provide a keel assembly which is adjustable according to the course of the vessel to achieve optimum keel configuration for efficient performance. Other objects and advantages of the invention will become apparent from the following descrip-tion.
The present invention provides a hydrofoil comprising a rigid supporting body adapted to be fixed to a vessel to ex-tend outwardly therefrom and said supporting body providing forwardly converging abutment faces at opposite sides thereof, a foil-shaped outer casing extending about said rigid support-ing body in such manner that the incidence plane of the casing when disposed symmetrically is substantially parallel to the fore and aft axis of the vessel and the sides of said casing are spaced equally from said abutment faces, said casing being formed of flexible material and being supported at its leading and trailing end portions by respective fore and aft pivot blade assemblies connected to said supporting body for pivotal ~3~
1()6;~()9~
movement about respective outwardly extending axes adjacent the leading and trailing edges of said supporting body and said axes being disposed substantially parallel to said incidence plane, said aft pivot blade assembly being pivotally connected adja-cent its leading edge to said rigid supporting body to permit the trailing edge of said aft pivot blade assembly to be dis-placed laterally to either side of itssymmetrical position whereby the casing at said either side may be formed to a con-cave shape and be supported against the respective said abutment face, and there being provided torque transferring means opera-tively interconnecting said fore and aft pivot blade assemblies to cause the latter to pivot oppositely to one another. ;
In order that the invention may be more readily under-stood and put into practical effect, reference will now be made to the accompanying drawings which illustrate one embodiment of the invention as applied to keel assemblies of sailing vessels, and wherein:-Fig. 1 is a side view of a keel assembly fitted to the underside of a sailing vessel;
Fig. 2 is a similar side elevational view showing only the main suppo~t structure for the keel assembly;
Fig. 3 is a cross-sectional view along the line 3-3 of Fig. 1, and showing the keel assembly disposed in its normal or downwind position;
Fig. 4 is a view similar to Fig. 3 showing the keel assembly disposed in a tacking position; and Fig. 5 is a cross-sectional view similar to that of Fig. 4, but illustrating an alternate embodiment of the inven-tion.
As shown in Figs. 1 to 4, the keel assembly 10 is fit-ted to the underside of a vessel 11. The keel assembly in this embodiment comprises a support structure 12 extending downwardly from the bottom of the vessel and terminating in a lead bulb arrangement 13. The support 106Z~9~
.
structure 12 provides a support for the movable keel portion 14 which, in this embodiment, includes a rudder blade 15 supported pivotally on the vertically extending shaft 16 and a leading portion 17 supported pivotally on the forward vertical shaft 18. The shafts 16 and 18 are connected between the underside of the hull 11 and the upper end portions of the bulb arrangement 13. As can be ,. .
seen clearly from Fig. 2, the support strut 19 terminates inwardly of the ends of the lead bulb 13 so that the latter project outwardly therefrom and suitably reinforced to provide a support for the shafts 16 and 18.
In this embodiment~ both the leading portion 17 and the trailing rudder blade 15 are freely pivotable about thelr respective support shafts 18 and 16. The leading portlon 17 comprlses a rigld nose portlon 20 with flexible side plates 21 extending rearwardly therefrom to overlap the trailing rudder blade at 22 as illustrated. The -~
side plates 21 are connected together at their trailing ends by a transversely extending vertical bar 23 connected to the respective side plates 21 by hinge means 24. This bar 23 maintains the rear portions of the side plates 21 in their correct distance apart so as to neatly overlap the rudder blade 15 while the central portions 25 of the side plates 21 are maintained in spaced-apart attitude by abutment against an internally disposed bar 26 which passes slidably through an aperture 27 in the support strut 19. The latter is also provided with additional through-passages 28 to enable flow therethrough of water as the disposition of the keel assembly is varied.
10~2091 In this respect, it will be seen that the vertical side faces 29 of the support strut 19 are - -so shaped as to closely accommodate thereagainst in ` ~`
abutting relationship the face of the concave-shaped windward side plate 21. Thus, the support strut 19 is symmetrical about the centre line.
In operation, the keel assembly 10 according to the present invention when fitted to a vessel<sailing ~- i downwind, would be disposed in its symmetrical attitude c as illustrated in Fig. 3 as the pressure against either side plate 21 would be equal. However, if the vessel is heated to windward~ say on a port tack~ the starboard side plate 21s will be sub~ect to a positive water pressure as indicated by the lines P which will cause the side plate 21s to move laterally into abutting engagement with the support strut 19 and force the port side plate 21p outwardly by means of the rod 26 which will push against the inside face of the port plate 21p. Furthermore, the i vertical bar 23 connected by the hinges 24 to the side plates 21s and 21p will cause pivoting of the h$nges 24 connecting the overlapping portions 22 of the side plates. This action will pivot the trailing rudder blade 15 to its new position as illustrated in Fig. 4. It will be seen that in this position, the hydrofoil shape of the -fin 10 will provide a positive lift to windward due to the positive pressure P at the leeward side and the negative pressure indicated by the lines N on the windward side.
The reverse position of the rudder assembly 10 for the starboard tack is shown superimposed in dotted outline.
` `
In this construction, it will be seen that the rudder actuation is automatic and no through~hull fittings are required to actuate the keel assembly.
In the embodiment illustrated in Fig. 5, the side plates 121 of the keel assembly 110 extend between a leading pivot assembly 120 and a trailing rudder assembly 115. The side plates include a vertical expansion ~oint, expandable in the fore and aft direction -so that their longitudinal dimensions may be varied -according to the disposition of the keel assembly. In this embodiment, the pivoting of the leading pivot assembly 120 and the trailing rudder assembly 115 is positively ;
controlled by means of eccentric members 30 and 31 fitted to centrally disposed vertical shafts 118 and 116~
respectively~ which pass sealably through fittings in the bottom of the vessel to a station where their pivotal movement may be selectively controlled. In this manner, the dispositlon of the keel assembly may be accurately controlled so that say the fullness of the effective keel section may be selectively varied according to the speed of the vessel and/or its angle of attack with respect to the wind. Also, as shown in this embodiment~ there may be provided an additional trim or rudder blade 32 fitted to a shaft 33 at the rear of the keel assembly and actuable from within the vessel. It will be seen that the leading pivot assembly 120 is located between the front pivot bar 34 and the rear eccentric member 30 while the trailing rudder assembly is located between a vee-portion 35 which engages in a Y-notch arrangement 36 ~ ~.
~. . .
in the rear vertical face of the main support structure ~
119~ and the eccentric member 31. '!'~''',.': ', Of course, it is not essential to provide a keel assembly with two actuating shafts, more or less may be used depending upon the particular application.
The keel assembly according to the present invention may be also provided with locking devices to lock the keel ~
assembly in its selected position. Furthermore, the keel '-according to the present invention may be retractable . - .
and ap~liet to unballasted vessels as desired. As indicated at the beginning of the specification, such assemblies could be used as rudders or as stabilising fins for Yessels.
In 8 further variation, the fin keel assembly comprises curved side plates fixed rigidly together along their leading edges and provided with a slotted connection at their trailing edges and there is provided within the side plates actuating means such as a hydraulic ram to vary the chord length of one side plate whereby the fin ;,`
keel assembly may be selectively disposed asymmetrically to cause lift in either lateral direction resultant from forward motion through the water.
However, while the above has been given by way of illustrative example, it will be understood that the many variations of constructional detail and design that may be made to the described embodiments by persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is defined in the appended claims.
', THIS INVENTION relates to undërwater appendages particularly such appendages adapted to derive a lift from forward passage through the water.
Many vessels of different types employ underwater lift devices in various circumstances and generally in the form of a fin. ~or example, most vessels are steered by means of a rudder which provides selectively a lift ~-to one side or the other to change the course of the vessel. Other vessels, particularly large commercial vessels, employ stabiliser fins at each side of the vessel, each adapted to apply either for lift in a~ upward or downward dire¢tio~, whichever is the reverse of the op~osite stabiliser fin~ to reduce the rolling of the vessel, and sailing vessels are provided with a keel .
~5 assembl~ to enable them to tack to wi~dward.
~he present invention aims to provide an improved - underwater appendage which may be utilised in the above-mentioned and other applications. ~or illustrative purposes, ,, ",...
the present specification will hereinafter describe the application of the invention to the fin keel assembly of a sailing vessel.
As is well known, sailing boats advance to windward in a zig-zag path because it is not possible to sail directly into the wind. Thus, it is an advantage for a sailing craft to be able to point high into the wind inorder to minimise the distance sailéd to windward.
Apart from the effect of the sails, the ability of a vessel to sail to windward is partly determined by the hull shape and in particular by the shape of the ~eel .. .
~.
- 106~91 assembly which acts to prevent sideway movement of the boat relative to its straight-ahead direction.
As the vessel has to travel in a zig-zag direction, it is of course necessary for the vessel to be able to point high into the wind on both the port and starboard tack and this condition has resulted in most sailing boats having a centrally-disposed symmetrical fin keel. The section most often chosen is a streamlined symmetrical hydrofoil section, preferably with a high aspect ratio. `
While there have been attempts to provide vessels with laterally spaced asymmetrical keels which may be lowered independently according to the tack the vessel is on, such attempts have not been particularly successful because of their complexity and their need for constant tending and be-cause on other points of sailing, they are not as efficient as the central fin keel arrangement.
Accordingly, it is an object of the present invention to provide a keel assembly which is adjustable according to the course of the vessel to achieve optimum keel configuration for efficient performance. Other objects and advantages of the invention will become apparent from the following descrip-tion.
The present invention provides a hydrofoil comprising a rigid supporting body adapted to be fixed to a vessel to ex-tend outwardly therefrom and said supporting body providing forwardly converging abutment faces at opposite sides thereof, a foil-shaped outer casing extending about said rigid support-ing body in such manner that the incidence plane of the casing when disposed symmetrically is substantially parallel to the fore and aft axis of the vessel and the sides of said casing are spaced equally from said abutment faces, said casing being formed of flexible material and being supported at its leading and trailing end portions by respective fore and aft pivot blade assemblies connected to said supporting body for pivotal ~3~
1()6;~()9~
movement about respective outwardly extending axes adjacent the leading and trailing edges of said supporting body and said axes being disposed substantially parallel to said incidence plane, said aft pivot blade assembly being pivotally connected adja-cent its leading edge to said rigid supporting body to permit the trailing edge of said aft pivot blade assembly to be dis-placed laterally to either side of itssymmetrical position whereby the casing at said either side may be formed to a con-cave shape and be supported against the respective said abutment face, and there being provided torque transferring means opera-tively interconnecting said fore and aft pivot blade assemblies to cause the latter to pivot oppositely to one another. ;
In order that the invention may be more readily under-stood and put into practical effect, reference will now be made to the accompanying drawings which illustrate one embodiment of the invention as applied to keel assemblies of sailing vessels, and wherein:-Fig. 1 is a side view of a keel assembly fitted to the underside of a sailing vessel;
Fig. 2 is a similar side elevational view showing only the main suppo~t structure for the keel assembly;
Fig. 3 is a cross-sectional view along the line 3-3 of Fig. 1, and showing the keel assembly disposed in its normal or downwind position;
Fig. 4 is a view similar to Fig. 3 showing the keel assembly disposed in a tacking position; and Fig. 5 is a cross-sectional view similar to that of Fig. 4, but illustrating an alternate embodiment of the inven-tion.
As shown in Figs. 1 to 4, the keel assembly 10 is fit-ted to the underside of a vessel 11. The keel assembly in this embodiment comprises a support structure 12 extending downwardly from the bottom of the vessel and terminating in a lead bulb arrangement 13. The support 106Z~9~
.
structure 12 provides a support for the movable keel portion 14 which, in this embodiment, includes a rudder blade 15 supported pivotally on the vertically extending shaft 16 and a leading portion 17 supported pivotally on the forward vertical shaft 18. The shafts 16 and 18 are connected between the underside of the hull 11 and the upper end portions of the bulb arrangement 13. As can be ,. .
seen clearly from Fig. 2, the support strut 19 terminates inwardly of the ends of the lead bulb 13 so that the latter project outwardly therefrom and suitably reinforced to provide a support for the shafts 16 and 18.
In this embodiment~ both the leading portion 17 and the trailing rudder blade 15 are freely pivotable about thelr respective support shafts 18 and 16. The leading portlon 17 comprlses a rigld nose portlon 20 with flexible side plates 21 extending rearwardly therefrom to overlap the trailing rudder blade at 22 as illustrated. The -~
side plates 21 are connected together at their trailing ends by a transversely extending vertical bar 23 connected to the respective side plates 21 by hinge means 24. This bar 23 maintains the rear portions of the side plates 21 in their correct distance apart so as to neatly overlap the rudder blade 15 while the central portions 25 of the side plates 21 are maintained in spaced-apart attitude by abutment against an internally disposed bar 26 which passes slidably through an aperture 27 in the support strut 19. The latter is also provided with additional through-passages 28 to enable flow therethrough of water as the disposition of the keel assembly is varied.
10~2091 In this respect, it will be seen that the vertical side faces 29 of the support strut 19 are - -so shaped as to closely accommodate thereagainst in ` ~`
abutting relationship the face of the concave-shaped windward side plate 21. Thus, the support strut 19 is symmetrical about the centre line.
In operation, the keel assembly 10 according to the present invention when fitted to a vessel<sailing ~- i downwind, would be disposed in its symmetrical attitude c as illustrated in Fig. 3 as the pressure against either side plate 21 would be equal. However, if the vessel is heated to windward~ say on a port tack~ the starboard side plate 21s will be sub~ect to a positive water pressure as indicated by the lines P which will cause the side plate 21s to move laterally into abutting engagement with the support strut 19 and force the port side plate 21p outwardly by means of the rod 26 which will push against the inside face of the port plate 21p. Furthermore, the i vertical bar 23 connected by the hinges 24 to the side plates 21s and 21p will cause pivoting of the h$nges 24 connecting the overlapping portions 22 of the side plates. This action will pivot the trailing rudder blade 15 to its new position as illustrated in Fig. 4. It will be seen that in this position, the hydrofoil shape of the -fin 10 will provide a positive lift to windward due to the positive pressure P at the leeward side and the negative pressure indicated by the lines N on the windward side.
The reverse position of the rudder assembly 10 for the starboard tack is shown superimposed in dotted outline.
` `
In this construction, it will be seen that the rudder actuation is automatic and no through~hull fittings are required to actuate the keel assembly.
In the embodiment illustrated in Fig. 5, the side plates 121 of the keel assembly 110 extend between a leading pivot assembly 120 and a trailing rudder assembly 115. The side plates include a vertical expansion ~oint, expandable in the fore and aft direction -so that their longitudinal dimensions may be varied -according to the disposition of the keel assembly. In this embodiment, the pivoting of the leading pivot assembly 120 and the trailing rudder assembly 115 is positively ;
controlled by means of eccentric members 30 and 31 fitted to centrally disposed vertical shafts 118 and 116~
respectively~ which pass sealably through fittings in the bottom of the vessel to a station where their pivotal movement may be selectively controlled. In this manner, the dispositlon of the keel assembly may be accurately controlled so that say the fullness of the effective keel section may be selectively varied according to the speed of the vessel and/or its angle of attack with respect to the wind. Also, as shown in this embodiment~ there may be provided an additional trim or rudder blade 32 fitted to a shaft 33 at the rear of the keel assembly and actuable from within the vessel. It will be seen that the leading pivot assembly 120 is located between the front pivot bar 34 and the rear eccentric member 30 while the trailing rudder assembly is located between a vee-portion 35 which engages in a Y-notch arrangement 36 ~ ~.
~. . .
in the rear vertical face of the main support structure ~
119~ and the eccentric member 31. '!'~''',.': ', Of course, it is not essential to provide a keel assembly with two actuating shafts, more or less may be used depending upon the particular application.
The keel assembly according to the present invention may be also provided with locking devices to lock the keel ~
assembly in its selected position. Furthermore, the keel '-according to the present invention may be retractable . - .
and ap~liet to unballasted vessels as desired. As indicated at the beginning of the specification, such assemblies could be used as rudders or as stabilising fins for Yessels.
In 8 further variation, the fin keel assembly comprises curved side plates fixed rigidly together along their leading edges and provided with a slotted connection at their trailing edges and there is provided within the side plates actuating means such as a hydraulic ram to vary the chord length of one side plate whereby the fin ;,`
keel assembly may be selectively disposed asymmetrically to cause lift in either lateral direction resultant from forward motion through the water.
However, while the above has been given by way of illustrative example, it will be understood that the many variations of constructional detail and design that may be made to the described embodiments by persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is defined in the appended claims.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A hydrofoil comprising, a rigid supporting body adapted to be fixed to a vessel to extend outwardly therefrom and said supporting body providing forwardly converging abutment faces at opposite sides thereof, a foil-shaped outer casing extending about said rigid supporting body in such manner that the incidence plane of the casing when disposed symmetrically is substantially parallel to the fore and aft axis of the vessel and the sides of said casing are spaced equally from said abutment faces, said casing being formed of flexible material and being supported at its leading and trailing end portions by respective fore and aft pivot blade assemblies connected to said supporting body for pivotal movement about respective outwardly extending axes adjacent the leading and trailing edges of said supporting body and said axes being disposed substantially parallel to said incidence plane, said aft pivot blade assembly being pivotally connected adjacent its leading edge to said rigid supporting body to permit the trailing edge of said aft pivot blade assembly to be displaced laterally to either side of its symmetrical position whereby the casing at said either side may be formed to a concave shape and be supported against the respective said abutment face, and there being provided torque transferring means operatively interconnecting said fore and aft pivot blade assemblies to cause the latter to pivot oppositely to one another.
2. A hydrofoil according to Claim 1, wherein the opposite sides of said casing slidably overlap said aft pivot blade assembly and wherein said over-lapping portions of said casing are held together by means of a bar extending therebetween and being connected pivotally to the respective opposite sides of said casing.
3. A hydrofoil according to Claim 2, wherein said fore pivot blade assembly is pivoted rearwardly of its leading edge whereby said leading edge may be displaced laterally to said either side of said symmet-rical position.
4. A hydrofoil according to Claim 1, wherein said supporting body extends outwardly from the vessel to the outer extremity of said hydrofoil and constitutes a ballast keel for a sailing vessel.
5. A hydrofoil according to Claim 4, wherein said outer casing is formed from a continuous non-corrosive flexible sheet which is shaped to fit about said fore pivot assembly to extend rearwardly thereof to overlap said aft pivot assembly.
6. A hydrofoil according to Claim 3, wherein there is provided a selectively operable actuating assembly for controlling the shape of said hydrofoil, said actuating assembly including operating means operable to cause pivoting of said fore and aft pivot blade assemblies and said operating means being actuable remote from said hydrofoil.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU527076 | 1976-03-19 | ||
| AU619376 | 1976-06-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1062091A true CA1062091A (en) | 1979-09-11 |
Family
ID=25611188
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA274,202A Expired CA1062091A (en) | 1976-03-19 | 1977-03-17 | Under-water appendages for vessels |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1062091A (en) |
| FR (1) | FR2344441A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2019785B (en) * | 1978-04-25 | 1982-07-07 | Guigan F | Sailboat with an inclinable keel board |
| DE3126371C2 (en) * | 1981-07-03 | 1986-04-03 | Mistral Windsurfing AG, Nürensdorf | Device for course stabilization and reducing drift of watercraft, in particular sword or fin for sailing boards |
| EP0242408B1 (en) * | 1986-04-16 | 1991-07-17 | Wilhelm Laib | Sail boat |
| WO2011159156A2 (en) * | 2010-06-15 | 2011-12-22 | Binkhorstdesign Beheer Bv | A boat |
| NL2005562C2 (en) * | 2010-10-22 | 2012-04-24 | Binkhorstdesign Beheer B V | BOAT. |
| NL2004891C2 (en) * | 2010-06-15 | 2011-12-19 | Binkhorstdesign Beheer B V | SAILBOAT. |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE376152C (en) * | 1920-06-22 | 1923-05-24 | Emil Palmblad | Sword for sailing ships |
| US1924871A (en) * | 1931-06-26 | 1933-08-29 | Ludington Charles Townsend | Boat keel |
| FR1409241A (en) * | 1964-02-14 | 1965-08-27 | Improvements to sailboat daggerboards | |
| US3753415A (en) * | 1971-11-30 | 1973-08-21 | S Burtis | Hydrofoil-shaped stabilizing or attitude-affecting means for boats |
-
1977
- 1977-03-17 CA CA274,202A patent/CA1062091A/en not_active Expired
- 1977-03-18 FR FR7708116A patent/FR2344441A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2344441B1 (en) | 1984-12-07 |
| FR2344441A1 (en) | 1977-10-14 |
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