Low-drag fin and foil system for surfboards
OwnerKirby J. Meadinventor
Life of this patent
Estimating the term…
Abstract
The present invention is a Low-Drag Fin and Foil System for Surfboards (10), particularly including cambered fin foils (40; 42). The invention (10) also discloses low-drag, directionally unstable fin positions wherein the lesser of negative angle of attack of a trailing fin (50), versus the higher or positive angle of attack of a forward fin (48), makes the board (12) highly maneuverable by creating a yawing moment that aids the rotation of the board (12) as it is turned. The system particularly utilizes fins (40) having foil (42) shapes in which either the cambered side (74) or the non-cambered side (76) is provided with a combination of a convex curvature (68) and a concave curvature (70) to result in an oscillating curvature (72) which has a positive effect on control and acceleration.
Claims8
A surfboard comprising:
- a board having a nose region, a center, a tail region, and a longitudinal centerline passing from the nose region to the tail region, wherein the nose and tail regions comprise a nose edge and a tail edge delimiting a front edge and a rear edge at a very extremity of the board, and the center is a point equidistant from the very extremity of the board at either end, further wherein the board comprises a plurality of independent side-fins on a bottom surface of the board, and the independent side-fins are positioned in a multi-fin arrangement, and the multi-fin arrangement comprises:
- an independent rearward side-fin extending from the bottom surface of the board;
- and
- an independent forward side-fin extending from the bottom surface of the board and positioned forward of the rearward side-fin,
- wherein the rearward side-fin is set at a lesser angle of attack with respect to the longitudinal centerline and the forward side-fin is set at a positive angle of attack with respect to the longitudinal centerline, and further wherein the independent side-fins in the multi-fin arrangement are located forward of the rear edge at the every extremity of the tail, behind the center of the board, offset from the longitudinal centerline, and further wherein the juxtaposition of the side-fins is such that it creates a yawing moment that aids the rotation of the board in a turn.
A surfboard comprising:
- a board having a nose region, a center, and a tail region with a longitudinal centerline passing from the nose region to the tail region, wherein the nose and tail regions comprise a nose edge and a tail edge delimiting a front edge and a tail edge at a very extremity of the board, and the center is a point equidistant from the very extremity of the board at either end, wherein the board comprises a plurality of independent side-fins on a bottom surface of the board body, and the independent side-fins are hydrofoils positioned in a multi-fin arrangement, wherein the multi-fin arrangement comprises:
- an independent rearward side-fin that extends from the bottom surface of the board that is set at a negative angle of attack with respect to the longitudinal centerline of the board, and an independent side-fin that extends from the bottom surface of the board that is set forward of the rearward side-fin, and further wherein the rearward side-fin is set behind the forward side-fin, and the forward side-fin is set at an angle of attack that is substantially parallel to the longitudinal centerline of the board, and further wherein both the forward side-fin and rearward side-fin are located forward of the tail and behind the center of the board, and offset from the longitudinal centerline, and further wherein the juxtaposition of the side-fins is such that in a fluid flow of water the rearward side-fins and the independent side-fin are hydrofoils that redirect a flow of water and create a yawing moment that aids the rotation of the surfboard in a turn.
Dependencies are inferred from the claim text.