Every surfer should know a little about surfboard design. I’m always amazed at how little even some of the most proficient surfers know about what makes their board perform. Knowing some of the basics will help you to have an intelligent conversation with your shaper about your next board. It will also allow you to better evaluate the features of a board being hyped by the sales guy at your local surf shop. When you buy a car you don’t need to know how the air-fuel mixture is calibrated, but you should know the performance difference between a “V-8” and a “V-6” engine, or an automatic and a stick-shift transmission. There are six main features you should know about: Outline, Rocker, Rails, Foil & Bottom Contours, Tail Shapes and Fins.
It’s important to remember that a well made surfboard is an integrated and balanced design. Every design feature impacts performance and must be considered in relation to all other design features. Usually, there are performance trade-offs that must be made. A board with a lot of rocker at both ends will not be as fast as a board with minimal rocker, but the rockered board will turn much easier and much quicker. As a surfer, I might be willing to sacrifice some ease of turning for more speed, or vice-versa. A “dog” is a shape in which the performance trade-offs are so striking that the board is essentially un-rideable. A “magic” board is one in which performance trade-offs are barely detectable.
The shaper has to balance the board, keeping in mind the performance requirements of it’s intended rider. I might compensate for speedy, low tail rocker by increasing fin toe-in slightly, then I would have a board that is pretty fast but not overly stiff. Or I might increase thickness along the stringer by 1/8″ to accommodate thinner rails, making them easier to sink into a turn while keeping overall volume in the right place. Try not to focus on any one design attribute, instead look for balance and harmony in your board. “The whole is greater than the sum of the parts.”
Every shaper has his own ideas about design, and what makes a board work. And, while there is some consensus among shapers regarding basic design theory, there is also some disagreement. Keep in mind that surfboard design over the years has relied upon a trial-and-error approach, as in “move that fin 1/4” back and see what happens”. What we have is a lot of experiential data, with after-the-fact explanations and speculations. Add to that the variables of wave size and shape, rider age and size, and so on, and you can easily see why surfboard design is not an exact science. However, knowing a few of the basic design features will help you to make a better choice when selecting a board. What follows are the basic concepts of surfboard design as I have come to know them.