A lightweight surfboard that is rigid yet provides uniform flex characteristic without the use of a traditional wooden stringer includes a stringerless blank foam and a set of channels shaped into a top portion of the body of the surfboard. The set of channels comprises a pair of adjacent, axially extending elongated concave grooves that run along the length of the set of channels, meet at their end points and form a convex center section. The convex center section of the set of channels provides the support to prevent the board from breaking due to the bending of the surfboard while being ridden on the wave. A laminating layer may be glassed on the set of channels for additional strength. The laminating layer may include fiberglass cloth, Kevlar, carbon fiber or any suitable material.