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US 7,244,157 B2Granted
High-lift, low drag fin for surfboard and other watercraft
OwnerDouglas James Simpsoninventor
Life of this patent
Estimating the term…
Abstract
This invention discloses a fin, for use on a surfboard and other watercraft, of a low-drag, high-lift, high-aspect-ratio, low-sweepback-angle planform of symmetrical foil section, with a fit root section that has a forwardly projecting leading edge and cutaway at the trailing edge, alone or in combination with winglets placed on the vertical fin element so as to minimize tip-vortex drag, so as to make the surfboard or watercraft more maneuverable, easier to propel through the water, and to stabilize the surfboard or watercraft.
Claims11
A fin for a water sports board comprising:
- a fin element having a fin base and a fin root section adjacent said fin base, and having a fin tip with a dimension between said fin root section and said fin tip, said fin element having a fin element leading edge and a fin element trailing edge;
- said fin root section being forwardly displaced from a remainder of said fin element, and having a fin root section leading edge projecting beyond said fin element leading edge and a fin root section trailing edge exhibiting a cutaway from said fin element trailing edge;
- said fin element having an aspect ratio of 2:1 or greater and a quarter-chord sweepback in a range between 0 and 25 degrees;
- said fin element having a fin element cross-section from said fin element leading edge to said fin element trailing edge that is perpendicular to said dimension, said fin element cross-section having a symmetrical foil shape;
- and
- said fin tip having a fin tip cross-section from said fin element leading edge to said fin element trailing edge that is perpendicular to said fin element cross-section, said fin tip cross-section having a shape identical to said symmetrical foil shape divided along a line between said fin element leading edge and said fin element trailing edge.
3 more elements
A fin for a water sports board comprising:
- a fin element having a fin base and a fin root section adjacent said fin base, and having a fin tip with a dimension between said fin root section and said fin tip, said fin element having a fin element leading edge and a fin element trailing edge;
- said fin root section being forwardly displaced from a remainder of said fin element, and having a fin root section leading edge projecting beyond said fin element leading edge and a fin root section trailing edge exhibiting a cutaway from said fin element trailing edge;
- said fin element having an aspect ratio of 2:1 or greater and a quarter-chord sweepback in a range between 0 and 25 degrees;
- said fin element having a fin element cross-section from said fin element leading edge to said fin element trailing edge that is perpendicular to said dimension, said fin element cross-section having a symmetrical foil shape;
- said fin element cross-section having a maximum width and said fin element having opposite sides defining said fin element cross-section;
- said fin tip having a fin tip cross-section from said fin element leading edge to said fin element trailing edge that is perpendicular to said fin element cross-section;
- and
- at least one planar winglet having a foil-shaped winglet cross-section and having a winglet chord length, said at least one planar winglet being attached at one of said sides of said fin element at a location substantially equal to said winglet chord length upwardly from said fin tip, said at least one wing let extending outwardly from one of said sides of said fin element from said fin tip trailing edge horizontally forwardly toward said fin tip leading edge to said maximum width of said fin element cross-section.
5 more elements
Dependencies are inferred from the claim text.