Patent ID: 6991503

Claim:
A fin assembly for adjustably coupling a fin to a board used for supporting a user upon a fluid during motion, the fin assembly comprising: (a) a fin having a base, the base including a substantially semicircular portion and a front tip; (b) a fin box adapted to be attached to a board, the fin box having an opening for receiving the base of the fin, wherein a rear end of the opening has a substantially semicircular portion for receiving the semicircular portion of the base and wherein a front end of the opening has a plurality of rifts, wherein the front tip of the base is adapted to be selectively disposed in one of the plurality of rifts, and wherein changing the rift that the front tip is disposed in changes an angle of the fin with respect to a longitudinal axis of the board; and (c) a fastening assembly for removably securing the fin to the fin box.