Defining the parameters
The most obvious factors that play a role in a surfboard's context are physical in nature; from the surfer's weight to the size and shape of the wave. These are taken into consideration when deciding on a surfboard's length, width and thickness/volume. The design process thus builds a bridge between context and shape, based on function. However, the ultimate aim of surfboard design is to build a bridge between shape and purpose, since the ideal is a surfboard that becomes absorbed into the surfer's intentions. So, the surfer's intentions are also part of the surfboard's context, making it part of the design process, too.
In considering the surfer's intentions, the designer analyses how the surfer's movements affect the response of the surfboard. Basically, the surfer turns the surfboard by leaning his body and extending his legs and feet to varying degrees. However, it is not the mechanics of the human body that concerns the designer, but the net affect. So, the designer reduces the surfer's influence to a set of rotational axes. At this level of abstraction, the surfer's intentions can be represented diagrammatically, enabling the designer to more easily visualize the different phases of a maneuver, as well as the transitions between them.
Whatever the axis of rotation, maneuvers can be divided into two phases, a penetration phase and a release phase. The penetration phase is characterized by the inward rotation of the surfboard, while the release phase involves its outward rotation. By visualizing each phase in terms of its rotational axis, or sequence of axes, the designer can identify which portions of the surfboard come into play for a given maneuver.
Having established a link between the surfer's actions and the under surface of the surfboard, the designer is ready to include the notion of resistance. The focus here is on the degree of drop-off allowing the water to escape. So, a straight line is drawn across the bottom surface, depicting the flow of water. From this, a cross-section of the bottom contours is drawn on a piece of graph paper. The curve of this cross-section determines the force generated during the penetration phase of the maneuver. For example, a concave curve is more responsive than one which is convex.
For the sake of simplicity, the greatest amount of resistance is achieved by rotating the surfboard sideways, since the bottom curve aligned with this plane of rotation provides the least drop-off. Subsequently, the penetration phase of a maneuver tends to be characterized by rotation of the board in or near to this plane. By contrast, the release phase is characterized by a transition from this rotational plane toward either the center plane, by directing the water out through the tail, or into the horizontal plane, by sliding the tail out. The horizontal plane obviously provides the least resistance, since it is limited to the surface area of the fins. However, the loss of resistance felt in the central plane results from the surfboard's rocker, since the greatest amount of surface drop-off is directed through the tail.
The blending of these curves, which fan out from the center of the board, influences the transition from rail-penetration to release through the tail. Although curvature from nose to tail and from side to side, by themselves, determine the extent to which penetration and release contribute to a surfboard's performance, it is the blending of curves between these two extremes that ensures that the board enters and exits turns smoothly and with minimal loss of speed.
Although surfboards can be represented in 3D, with movements reduced to rotational axes, surfing manoeuvres are as much the transition between rotational axes as the axes themselves. So, it is exceptionally difficult to visualise at this level of abstraction, without drawing on actual surfing experience. A shaper can sense the resistence felt by the surfboard during penetration, by imitating the flow of water with his fingers gliding across the surface of the board. By simultaneously invoking the feeling of a manoeuvre, he is able to perceive links between the shape of a board, a sequence of rotational axes and the path the board travels across a wave. The shaper grasps the 4th dimension of motion through memory of the authentic experience, with the physical sensation of form perceived in that context. He is the Sufi of naval architects, drawing on his own spirit to create the means for others to experience the fluid realm.
© 2006 Daniel Webber
