Abstract: Hydrodynamic ridge devices for mounting in pairs on the bottom of aquatic sports watercraft to form channels that capture lateral water flow and direct it longitudinally to enhance stability, speed, control, and performance of the watercraft. Each ridge device is a longitudinal body with a short flat vertical side, a wide flat top side extending horizontally from the top of the vertical side perpendicular thereto terminating in a convex generally arcuate outer edge, and a convex curved bottom side. The vertical side has an arcuate bottom edge that curves upwardly to a point at each end. The outer edge of the top side curves inwardly at each end to the points at the ends of the vertical side, and the curved bottom side curves upwardly and outwardly from the bottom of the vertical side to join the outer edge of the top side and the vertical side end points.