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SURFBOARD DESIGN
OUTLINE
Although much of the board's riding characteristics can be attributed to the outline, one must realize that it is simply one element in a much larger assemblage of contents that makes up the final shape. But each of the three measurements does provide its own defining contribution to the board's performance, and with that contribution usually comes some sacrifice to another aspect of the board's performance. For example, as the nose becomes wider, it becomes more stable to stand there. The down side of this is that widening the nose adds more volume of material or swing weight in front of you while turning, so the ease of turning diminishes. When the surfboard drops into a wave, a wider the tail will captures more water, thus causing better lift. As the tail design gets wider it becomes more and more stable but this will make it difficult to tip on an edge to turn. Boards that are wider in the mid section are more stable but are more difficult to turn because they don't tip up on a rail as easily as their narrower counterpart. The three measurements work in concert, and as one grows or reduces, it affects the others. If the nose and tail remain the same and the center width increases, the board gains stability. As the board gains stability, it also gets more difficult to tip on a rail to turn. Conversely, if the nose and tail increase in width and the center remains the same, the rails become more parallel, complimenting the nose ride but decreasing the maneuverability because there is little curve to cause drag in the turn. Increase the nose width and leave the other dimensions alone and it moves the wide point forward, reducing the center curve, making it more difficult to turn. Increase the tail dimension, and decrease the nose width, and it will make for great turns, but the board will be slow and a poor nose rider. Boards with a three-fin set up typically have a tail width of 14 1/2" or less. As the fins start getting too far apart with a wider tail, the rotational effect needed to turn is restricted. Single fins typically have a tail measurement greater than 14". Having the rotation of the turn split between the fin and rail increases the need for more curve to enhance the turn. A wider tail (at 12") achieves this. TAIL SHAPE
ROCKER
A key area of rocker is the area between 12 and 24 inches from the tail. There should be a bend in this area with a flatter curve forward of this bend. This joining of tail curve and flatter area of the mid section are one of the key elements of surfboard design and must be in concert with outline and rail shapes. It takes years of knowledge to know how much and where to put this bend. Increased tail rocker will ease turning and increase tip time. But it will slow paddling, down line speed and decrease drive out of the turn. Decrease the tail rocker and the board becomes stiffer in maneuverability, but the forward drive increases. I have spent nearly 50 years developing a good blend of rocker curves and they work. I don't go by nose and tail rocker numbers. The only way to accurately define a rocker is to take measurements every 6". There is nothing more important as the relationship of the previous curve of the rocker to the curve next to it. Numbers taken at the end of a surfboard cannot represent the total rocker curve. Lay a snow ski on a flat surface and you can see why. FOIL This is the thickness relationship deck to bottom. The foil on a surfboard is a delicate balance that is lost on any but the most consummate designer. At Harbour Surfboards, the foil is the first building block of the entire design. Too thick in the nose and it has swing weight problems in turning. A nose that is too thin will set too deep and track. Too thick in the tail and it is too corky to turn and too thin will paddle poorly. RAILS
Down turned rails are about 75% down in the middle of the outline, with a soft roll, quickly blending into a flat bottom. They usually change to full down turned rails with a hard edge about 20 to 24 inches from the tail. This is the area that the outline shape makes the transition into the tail curve. The hard edge in the tail area of the down rail board will grip the water allowing for fin designs with less total area. A fin should be of less volume on a board with hard tail rails than on a board with 50/50 rails. This is because the edge on a board with down tail rails is, along with the fin, gripping the wave. Boards with a down tail rail and a soft low mid rail, will initiate cut-backs better due to the fact that water isn't being trapped by wrapping the rail. They give more tail lift, and this makes them seem to accelerate faster which is sometimes referred to as drive. This rail design is not well suited for heavier boards. Rails will set into the wave to a depth relative to the rider's weight. Heavier surfers need more volume so it can either be put into thickness, which increases the rail size, or length or width, which will allow for thinner rails. FINS A fin is a compromise of grip and side drift. It is the device that gives direction and causes most of the lift that generates motion. The waves' energy is captured on the fin's surface creating upward pressure. The surfers' weight in front of this lift is the basic force that causes a surfboard to traverse across the wave. To turn a surfboard, the fin needs to be pushed through the water, but cannot totally release. The surfer's weight might be a consideration upon choosing a fin. One who is heavy for a given board length might choose a larger volume fin to compensate for his added force resulting from his weight. The converse applies to a lighter surfer for a board's volume. All fins: The wider the board is in the tail, requires the fin to be either longer or nearer the tail. Increased volume at the fin base traps more water for lift and drive. Reduced volume above the (immediate) base will reduce side drift. Increased fin rake (a term for the amount tip that overhangs the base) ads drive, but resists board rotation. Increased tip area reduces tail release while nose riding, but also decreases maneuverability.
FIN INSTALLATION AND PLACEMENT
Side Bites: O'Fish'L side bites are marked R & L. The foiled side always faces the rail. Make sure that the "Z clip" is at the rear of the box. Push the fin into the front of the box at about a 45¡ degree angle and rotate the rear downward until it snaps past the "Z clip". To remove, rotate the tip of the fin forward and pull out. http://www.ofishl.com/installation.htm. ADJUSTING THE CENTER FIN
CONCAVE AND NOSE CHANNELS These are nose riding embellishments to add lift when riding on the nose. The concave is a traditional technique in shaping to enhance nose riding. This style was popularized during the mid-sixties at the peak of the nose riding craze. There are many ways to carve it into the nose area and we believe it is most successful by continuing the scooped out area fairly close to the rail and leaving a smooth exit line at the rear. This takes some of the drag out that is generally attributed to concave noses. The other style is nose channels created by Rich Harbour.
The differences in feel of the two styles are slight but noticeable. The concave is a more of a stalling style, making it smooth and stable ride. The nose channels don't slow the board down when in the trim spot at about 1/3 back from the tip. Many better surfers claim to be able to climb and drop with them. We have applied each style to an appropriate shape in our line of boards. Enjoy! STRINGERS Stringer is the common name in surfboard construction for the piece or pieces of wood that divide the foam blank. The stringer is glued in after blank is removed from the mold. Stringers both give the blank rigidity for shaping, and the finished product. They also provide the shaper a sight line to use while shaping. Colored glue can be used to decorate the lamination. Harbour Surfboards uses colored glue to give a better site line when shaping the lighter colored basswood. Basswood: (Tilia americana) is a very clear grained hardwood that is easily shaped. It is light, with a specific gravity of just less than 0.4. To compare, Balsa (Ochroma pyramidalis which is also a hardwood) is 0.15 and Spruce 0.4. Lignum vitae, the heaviest wood, has a specific gravity of over 1.2. (This stuff doesn't even float!) Cedar: Due to redwood being over harvested, I have chosen to use cedar (Thuja plicata) a wood that visibly resembles redwood. Like redwood, cedar is almost 25% weaker than basswood. I recommend cedar only in three stringer boards or T-bands. Most people refer to T-bands as two alternate colored woods glued together in a pattern (e.g. cedar-balsa-cedar). T-Bands are known within the surfboard industry as more than on piece of wood or foam glued with another, which could be the same type of wood or foam. Be advised that these requests can sometimes add extra time of production. When using basswood, we use 1/4" width for the thicker boards and 3/8" for the thinner, high performance models. Shorter boards may have even narrower stringers. The word hardwood and softwood have nothing to do with the wood's hardness. All trees are members of the plant kingdom that are spermatophytes or seed plants. This kingdom is further divided into two broad groups (separated by how the seeds are born). Gymnosperms are naked seeds and comprise all trees that produce softwood lumber. Angiosperms are covered seeds (like walnut, pecan etc.) that make up the hardwood group.
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