The Flextail remains an equally fascinating concept and inseparable from the hull movement. It is the closest way to get the slide Greenough was experiencing, surfing standing up. The Flextail, a variable rocker concept, is adaptable to any sort of board that has zero tail rocker down. Although it will never replace a real tail rocker, usually starting from the wide of the board and evolving slightly to the tail. On the other hand, it creates a kicktail, existing only when necessary. Indeed, a board with a very tight or even nonexistent tail rocker offers a larger gliding surface and creates less turbulence so the board will be faster. Extremely fast. However, a board without a tail rocker is very complicated to turn. due to the lack of lift given by a tail rocker. Above because of resistance caused by too large a gliding surface, it doesn't allow the board to swing and keep the nose out of water or to engage in a new direction. The Flextail acts on a bottom turn or a cutback. It follows the shape of the wave, eliminating all resistance, creating a variable rocker. Which, once the bottom turn or cut back is completed, will return to its initial shape. Leaving the board again with a zero tail rocker. And engaging a perfect trim thanks to the back 3/4 of the board, flat, where no rocker or point of rupture can hamper the speed. It is nevertheless very complicated to have a satisfactory result if the surfer wishes to surf all types of waves with the same Flextail. Each specific flextail should be used for a specific type of wave. The power of the wave surfed determines the stiffness of the Flextail.