Patent ID: 7685959

Claim:
A surfboard comprising: a board front, a board midsection, a board tail end, a top side, an underside, and a central axis, wherein the underside comprises an underside right portion and an underside left portion; at least one fin removably connected to the underside proximate to the board tail end; a first graduated channel disposed in the underside left portion having a first front end shallower than a first tail end, wherein the first front end is proximate to the board midsection and the first tail end is proximate to the board tail end, and wherein the first graduated channel is substantially parallel to the central axis; a second graduated channel disposed in the underside right portion having a second front end shallower than a second tail end, wherein the second front end is proximate to the board midsection and the second tail end is proximate to the board tail end, and wherein the second graduated channel is substantially parallel to the central axis; and a keel disposed in the underside along the central axis separating the first graduated channel and the second graduated channel.