WO2017027921A1 - A fin for a surfboard - Google Patents
A fin for a surfboard Download PDFInfo
- Publication number
- WO2017027921A1 WO2017027921A1 PCT/AU2016/050756 AU2016050756W WO2017027921A1 WO 2017027921 A1 WO2017027921 A1 WO 2017027921A1 AU 2016050756 W AU2016050756 W AU 2016050756W WO 2017027921 A1 WO2017027921 A1 WO 2017027921A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fin
- side face
- accordance
- channel
- trailing edge
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B32/00—Water sports boards; Accessories therefor
- B63B32/60—Board appendages, e.g. fins, hydrofoils or centre boards
Definitions
- This disclosure relates to a fin for a water sport board system and particularly, but by no means exclusively, to a fin for a surfboard.
- Fins are provided on surfboards and other such watercraft to facilitate turning and provide general board stability. Without fins the rear end of the board would slide over the surface of the water with little control, particularly during a turning manoeuver.
- Surfboards commonly use anywhere between one and four fins (located toward the rear end of the board on its bottom surface). For a three finned configuration, there is typically provided a centre fin centrally located between a pair of side fins.
- Surfboard fins typically employ a convex or "foiled" surface, enabling them to operate as a type of hydrofoil wing, which can generate lift as the board travels through the water.
- the ability to generate lift may improve the turning capability of the board to which the fin is attached.
- trailing vortices created by the fin as it moves through the water can result in a reduction in lift as well as to create drag.
- a fin for a surfboard comprising: a body having a leading edge and a trailing edge; at least one channel defined on a first side face of the body, the at least one channel beginning at, or substantially at, the leading edge and extending at least partially toward the trailing edge and wherein the at least one channel widens as it extends toward the trailing edge.
- the channel widens substantially towards the trailing edge.
- the depth of the at least one channel decreases towards the trailing edge.
- the at least one channel extends substantially from the leading edge of the first side face to the trailing edge thereof. In an embodiment the at least one channel is longitudinally aligned with a surfboard abutment edge of the body.
- a plurality of channels are defined on the first side face of the body and wherein the channels are substantially evenly spaced along its length.
- the side face has a generally convex profile.
- the body has a second side face opposite the first side face and wherein the second side face is substantially planar or concave.
- the body has a second side face opposite the first side face and wherein the second side face also has a convex profile.
- At least one further channel is defined on the second side face of the body, the at least one further channel beginning at the leading edge and extending at least partially toward the trailing edge and wherein the at least one further channel widens as it extends toward the trailing edge.
- a fin for a surfboard comprising: a body having a leading edge and a trailing edge; at least one channel defined on a first side face of the body, the at least one channel beginning substantially at the leading edge and arcing downwardly toward a tip portion of the body.
- Figure 1 shows various elevation views of a centre fin in accordance with an embodiment
- Figures 2a and 2b are diagrams shown fluid flow results for a conventional fin and the fin of Fig. 1, respectively;
- Figure 3 is a side view of a side fin, in accordance with an embodiment
- Figure 4 is a partial view of a surfboard incorporating centre and side fins, in accordance with an embodiment.
- Figure 5 is a side view of a fin in accordance with an alternative embodiment
- the fin is designed for use with a surfboard and takes on a typical shark fin edge profile. More particularly, the fin 10 illustrated in Figure 1 is suitable for use as a stand-alone centre fin, or as a centre fin in a multi fin configuration.
- the fin 10 comprises a fin body 12 which has a leading edge 14 and a trailing edge 16.
- a board abutment edge 13 of the fin body 12 abuts a bottom surface of a board to which the fin 10 is attached.
- the fin body 12 comprises a first face 18 and an opposite second face 20. According to the illustrated embodiment, both faces 18, 20 of the fin body 12 have a convex profile. In this manner, the fin body 12 acts as a form of hydrofoil which functions to provide lift, in turn promoting stability and
- such a vertical fin is typically referred to as a "50/50" foil fin.
- a plurality of channels 22 are defined on both faces 18, 20 of the fin body 12.
- the channels 22 are longitudinally aligned with the abutment edge 13.
- the channels 22 begin to gradually widen.
- the channels 22 also become shallower as they extend, such that they have all but tapered out by the time they reach the trailing edge 16.
- the channel width at the leading edge 14 is about lmm and widens to about 5mm near the trailing edge 16. It will be appreciated that the actual widths may vary depending on the size of the fin and the desired flow dynamics.
- the water speed slows and becomes turbulent, extending well behind the fin.
- the incident water speed is the same (3ms) as for the fin of Fig. 2a, but it can be observed that the area of turbulence (in light grey) is greatly reduced. This turbulent area causes a reduction in speed/drag of up to 0.4ms (for both fins), but for the channelled fin of Fig. 2b quickly returns to normal flow in as little as one fin length.
- a fin 10' which is particularly configured for use as a side fin, in accordance with an embodiment.
- a first 'inner' face is configured for face toward a centre line of the board while the other 'outer' face 54 will face away.
- the outer face 54 has a convex profile while the inner face has a generally planar profile, as is typical for such side fins.
- This type of fin design is typically referred to as a "flat foil" fin.
- the side fin advantageously employs the same spaced apart channels 22 as previously described for the centre fin 10, on only the foiled outer face.
- Such a channelled side fin design may provide improved turning manoeuvrability, in addition to promoting laminar flow across the fin (i.e. as previously outlined for the centre fin 10).
- FIG. 4 With reference to Figure 4 there is shown a partial view of a surfboard 70 incorporating a centre fin 10 and a pair of side fins 10', in accordance with an embodiment.
- the fins 10, 10' secure to the board 70 via one or more board attachment projections (not shown) which extend from the board abutment edge 13 of the respective fin bodies.
- the projection(s) may be adapted to be removably secured to a mating structure on the bottom surface of the board, or alternatively may be
- the fins may include channels that divert upward or downward as they extend toward the trailing edge.
- the channels are not designed to promote laminar flow, but instead to induce spray during sharp turning manoeuvres.
- the channels (which may be mirrored on each face) may curve
- the channels may have a constant width and depth. In alternative embodiment, the channels may actually narrow as they extend toward the tip portion to further promote inducing of spray.
- the channels 22 begin to both widen and shallow out approximately half way between the leading edge 14 and trailing edge 16. It will be understood that this may not always be the case. Depending on the desired flow characteristics, the widening/shallowing can commence either closer to the leading edge 14 or closer to the trailing edge 16. Furthermore, it will be understood that the widening may occur before the channels 22 start to shallow and vice versa.
- channels 22 defined on the fin should not be seen as being limited to that shown in the figures.
- a smaller sized fin may carry fewer channels that a larger sized fin.
- the number of channels and corresponding spacing may be chosen to suit the desired flow characteristics for the fin.
- the fins 10, 10' and 10" as described herein can be formed of any suitable material including, fibreglass, glass, carbon fibre, aluminium, nylon, plastic or hard rubber. Further, it should be understood that the general shape of the fins should not be seen as being limited to that particular shape illustrated shown in the Figures. For example, the depth, area, sweep (i.e. the angle measuring how far the outline of the fin is curved backward) and foil can vary depending on waters port application, experience of rider, etc.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/753,288 US20180237112A1 (en) | 2015-08-18 | 2016-08-16 | A fin for a surfboard |
AU2016309959A AU2016309959A1 (en) | 2015-08-18 | 2016-08-16 | A fin for a surfboard |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2015903335 | 2015-08-18 | ||
AU2015903335A AU2015903335A0 (en) | 2015-08-18 | A Fin for a Surfboard |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2017027921A1 true WO2017027921A1 (en) | 2017-02-23 |
Family
ID=58050638
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AU2016/050756 WO2017027921A1 (en) | 2015-08-18 | 2016-08-16 | A fin for a surfboard |
Country Status (3)
Country | Link |
---|---|
US (1) | US20180237112A1 (en) |
AU (1) | AU2016309959A1 (en) |
WO (1) | WO2017027921A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USD977603S1 (en) * | 2022-09-27 | 2023-02-07 | Runwave Inc | Surfboard tail fin |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3141941A1 (en) * | 1981-10-22 | 1983-05-05 | Herbert 8000 München Schultes | Fin for a surfboard |
GB2136739A (en) * | 1983-03-25 | 1984-09-26 | Graeme Scott Attey | A fin, rudder or keel |
DE3425233A1 (en) * | 1984-07-09 | 1986-01-16 | Mistral Windsurfing AG, Nürensdorf | Device for stabilising the direction of travel of watercraft, in particular a centreboard or fin for windsurfing boards |
AU2003204735A1 (en) * | 2003-06-17 | 2005-01-13 | Webber, Daniel J | Improved Surfboard Fin |
AU320016S (en) * | 2008-03-04 | 2008-06-17 | Pj Whit Pty Ltd | Surf board |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5167551A (en) * | 1990-01-02 | 1992-12-01 | Davis Robert G | Bodysurfing and swimming aid |
US5306188A (en) * | 1991-11-06 | 1994-04-26 | Surfco Hawaii | Method of applying a safety/maneuver enhancing fin to a surfboard |
US6106346A (en) * | 1998-06-17 | 2000-08-22 | Bolen; Robert | Stabilizing fin for a water planing device |
USD437907S1 (en) * | 1999-04-13 | 2001-02-20 | Randy Owen Stuart | Surfboard fin |
WO2009070852A1 (en) * | 2007-12-07 | 2009-06-11 | John Gene Foster | A watercraft stability control device |
US20100219296A1 (en) * | 2008-11-01 | 2010-09-02 | Alexander J. Shelman-Cohen | Reduced drag system for windmills, fans, propellers, airfoils, and hydrofoils |
US8651813B2 (en) * | 2009-05-29 | 2014-02-18 | Donald James Long | Fluid dynamic body having escapelet openings for reducing induced and interference drag, and energizing stagnant flow |
AU344861S (en) * | 2012-05-28 | 2012-10-12 | 3Dfins Pty Ltd | Full dimple fin |
NZ703435A (en) * | 2012-05-28 | 2016-06-24 | Sideways Sports Ltd | Watercraft fin |
US9637205B1 (en) * | 2015-12-28 | 2017-05-02 | Jacob Saunooke | Curved surfboard fin |
-
2016
- 2016-08-16 US US15/753,288 patent/US20180237112A1/en not_active Abandoned
- 2016-08-16 AU AU2016309959A patent/AU2016309959A1/en not_active Abandoned
- 2016-08-16 WO PCT/AU2016/050756 patent/WO2017027921A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3141941A1 (en) * | 1981-10-22 | 1983-05-05 | Herbert 8000 München Schultes | Fin for a surfboard |
GB2136739A (en) * | 1983-03-25 | 1984-09-26 | Graeme Scott Attey | A fin, rudder or keel |
DE3425233A1 (en) * | 1984-07-09 | 1986-01-16 | Mistral Windsurfing AG, Nürensdorf | Device for stabilising the direction of travel of watercraft, in particular a centreboard or fin for windsurfing boards |
AU2003204735A1 (en) * | 2003-06-17 | 2005-01-13 | Webber, Daniel J | Improved Surfboard Fin |
AU320016S (en) * | 2008-03-04 | 2008-06-17 | Pj Whit Pty Ltd | Surf board |
Also Published As
Publication number | Publication date |
---|---|
US20180237112A1 (en) | 2018-08-23 |
AU2016309959A1 (en) | 2018-03-08 |
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