My take on Bob Simmons’ keel fin design, with forward belly, and concave between the twin keels. Inspired by Richard Kenvin’s explorations in all things Simmons (see www.hydronamica.com) and by inspecting a 1950 Simmons at the Surfing Heritage Museum in San Clemente. The board has beautiful momentum and drive, but I messed up the rocker and ended up with a vessel of two distinct halves, rather then the steady, even flow of a properly integrated surfboard bottom. So goes the process!