| How to Build Your First Surfboard by Stephen Pirsch |
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HALL OF FAME Mark Sadler |
SMALL WAVE DESIGN My friends and I have been experimenting with a very unusual shape that is suited to slow, small, choppy waves. The following design turns easily at low speeds, creating very little drag in the turn. This shape catches waves like a long - longboard, but is 2' - 3' shorter, and turns easily twice as fast. The design is 7' - 8' long, and 3" - 4" thick,
(depends on surfers weight) with about 2/3 of the total thickness
available 1' from the nose and tail. The fin box is a 7&1/2" Fins Unlimited
type (with this box the fins can be adjusted to a maximum of 13&1/2"
- from the tail end of the board to the trailing fin edge).
The board turns much looser with the fins all the way towards the
nose. The bottom and top are very flat rail to rail.
The rails are almost perfectly round everywhere (much better for
choppy conditions). The blue boards
shown in the photos, throughout the book, are small wave designs. A 8' x 25.5" x 3.5" design with the measurements below
will float a 170 lb. surfer with the entire top the board out of
the water. A 8' x 26" x 4" design design with the measurements below
will float a 220 lb surfer with the entire top of the board out
of the water. As a child, I remember thinking a board with a narrow tail would turn easier (as many ads suggest). At slow speeds just the opposite occurs. A narrow tail will sink at slow speeds, dragging water. A wide tail will plane on top of the water. These boards are designed to be turned by mostly twisting your body, instead of mostly leaning. This will create rotation (swivel) with the board relatively flat on the water, with very little drag. This design has been ridden since 2000, in many conditions, including
double overhead, but that is not remotely what it is made for.
It is best suited to gentle, knee to chest high, choppy waves. A NEW SMALL WAVE DESIGN In 2011, according to emails, hundreds, probably thousands, of small wave designs have been home built. Although the general surfing public considers the design an odity, many builders claim there is no other design as well suited to small, slow, choppy surf. Small Wave Design 2 is here. It is made for even smaller waves - 1' to 3' slow, choppy surf. The new design has a stiffer, slower turning characteristic compared to the old small wave design - this is due to the new design being more parrallel, and flater. However; the new design is significantly better suited to 1' to 3' surf, as it catches waves easier, planes through the flat spots and slow areas better, and turns with even less drag. This low drag is especially useful when comming out of a wave section on to a flat spot. The low drag design allows for a gradual turn back into the steeper section without fading out of the wave face. The older design turns faster, and is better suited to slightly larger surf. The drawings below show the earliest and latest versions of small wave design side by side. On the newest model, the twin fins are modified parrallelograms raked at 20 degrees, 3" wide, 6" long (as seen in the green tracing below) - these are cut from 7" molded cut away fins installed in Fins Unlimited Boxes cut to 5&1/2" long and installed 1&1/8" from the rail edge. The boxes are installed with the base higher on the tail end, in order to tilt the fin more towards 20 degrees (more upright, less rake). Note 1: Sliding the back foot towards the rail greatly enhances turning, in fact, it is unlikely you will ever appreciate the design without doing this. Note 2: The curvature between the half circles of the nose and tail, and the 30" wide point, can be created by using a piece of foam 5'x 1/2"x 1/2". At the end of the piece of foam mark the 1/2" thickness at 1/4". Draw a straight line from the Note 3: On the lastest version of the Small Wave Design 2, a 48"x 32"x 1/8" sheet of 90 psi vinyl foam sheet ($29.95 at fibreglast.com) was epoxied on the deck. This sheet is at least 3 times stronger than most surfboard foam, while being only about 50% heavier. This sheet used on the deck patch area (top rear 2/3 of board, starting 12" from tail tip) allows one layer of cloth to be used on the top and bottom and still have a much stronger than average deck area - a lighter and stronger board for roughly $10. more, after shipping, considering the savings on the deck cloth and resin. More labor is involved with the vinyl foam method compared to cloth deck patch method, as you will need to either plane the blank 1/8" to fit the vinyl or sand the vinyl edges flush. You should be able to reduce the weight about 2 lbs. and still have a stronger deck by using vinyl foam compared to an 8oz. cloth deck patch board. Note 4: For surfers wieghing over 160 lbs. I recommend using the 7" molded cutaway fins full size (not cut down) initially. If it feels stiff cut it down. You may prefer the smaller fins for smaller surf and the larger fins for larger surf. Most prefer one size for all waves.
PLANING HULL A surfboard should be designed as a planing hull. Most are designed with aspect ratios (width divided by length) similar to boats, boats being mostly displacement hulls. What this means in practical terms is: for planing it is beneficial to have a relatively flat, relatively wide, relatively rectangular area encompassing the majority of the bottom of a surfboard. The result can be a surfboard that reaches full plane at a lower speed, producing lift and reducing drag. Tests done by Lindsay Lord, a Naval Architect, show that a shape with an aspect ratio of .41 is optimal for planing. Most surfboards are around .20 - .30. Lord determined through wave pool and strain guage testing that a shape that looked similar to an elongated body board was optimim for planing. See also Hydrodynamica.com, Naval Architecture of Planing Hulls by Lindsay Lord and Surfing a Guide by William Nelson. Important parts of these two books can be accessed at http://mypaipoboards.org/pubs/BookSummaries.shtml - the books on this link are in alphabetical order. Note: Lindsay Lord and William Nelson love math formulas. Please consider skipping the math formulas and going directly to the charts or overall findings. I checked the math formulas, so you do not have to. The numbers are accurate. As always, what is most important is what you have the most fun on in the water. No math can calculate this. TAKE YOUR FIRST IMPRESSIONS FORWARD THIRTY WAVES On first impression a Small Wave Design will feel very different, maybe annoyingly so. The rider may feel that the board is sliding around in the water and is overly sensitive to any motion that may make it turn. Also some riders initially mention that the board seems to hang toward the top of the wave and tends not to drop quickly down the wave face as their less bouyant, and/or less surface area board does. Because the small wave design floats the rider with the entire top completely out of the water, the rider will feel every undulation in the water more acutely than before - this is the corky, squirely, twitchy, sliding around feeling, which no one seems to notice after a few days. The design is made to turn easily, to be sensitive; it is not supposed to track as most longboards do. Because this design is more bouyant and probably has more surface area than the riders previous board, it will catch the wave earlier (at the top), and tend to drop from the top of the wave to the bottom more gradually. So...in short, there is no cure for the complaints mentioned. People switiching from a submergered design to a full floatation design will likely have some of these feelings. It is important to ride about 30 waves and allow your muscle memory to function. This may take a few days of surfing decent waves. Most people are able to adjust to the difference, though there will always be those who feel a surfboard should be slightly submerged even at full plane, which is a contradiction. 1. Simply will not rip and carve. The Small Wave Design has the following positive characteristics. 1. Catches waves as easy as a long long board. |
