How to Build Your First Surfboard
by Stephen Pirsch

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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 7' x 25" x 3" design with the measurements below will float a 120 lb. surfer with the entire top of the board out of the water.
  14" tail tips
  20 &3/4" tail - 1' from the end
  20" nose - 1' from the end .

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.
  14"tail tips
  20&3/4" tail - 1' from the end
  20" nose - 1' from the end

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.
  16" tail tips
  21&1/2" tail - 1' from the end
  21&1/2" nose - 1' from the end

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.

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 dismisses the design as an oddity, those who try it often claim there is no other design as well suited to small, slow, choppy surf. Newer Small Wave Designs are here. These are made for even smaller waves - 1' to 3' slow, choppy surf. The new designs have a stiffer, slower turning characteristic compared to the old small wave design - this is due to the new designs being more parallel, and flatter. However; the new designs are significantly better suited to 1' to 3' surf, as they catch waves easier, plane through the flat spots and slow areas better, and turn with even less drag. This low drag is especially useful when coming 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 (relatively curved outline with more rocker and thinner tail) turns faster, and is better suited to slightly larger surf. The drawings below show the earliest and latest versions of small wave designs.

On the newer models, for surfers under 160 lbs., the twin fins are modified parallelograms raked at 20 degrees, 3" wide, 6" long (as seen in the green tracing below) - these can be cut from 7" molded cut away fins installed in Fins Unlimited Boxes cut to 5&1/2" long and installed 1&1/8" (or closer) 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). If over 160 lbs., use 7" molder cutaway fins full size, but do install boxes 1&1/8" from the rail edge, with the base higher on the tail end.

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 various half circles of the noses, and tails, 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
1/4" point to the full 1/2" thickness on the opposite long end of the foam (diagonal line). Sand the foam down to the line. This will give you a tapered piece 5'long with one end 1/2"x 1/2" thick and the other end 1/2"x 1/4" thick. By using the thinner end toward the area with more curvature (nose and tail), the foam will tend to create an even curvature from the nose and tail curves to the 30" wide point. The curved foam piece can be held to template material with duct tape at about 1' intervals. This is a cheap, easy way to create outline curvature on any board.

Note 3: On the later versions, 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. Also; expanded polystyrene foam can be be had in 40, 60, 80, and 100 psi sheets. A 60 psi sheet hotwire cut (or cut with a chain saw mounted on a table) to 3/8" thickness and glued to deck patch area makes a deck similar to vinyl foam above.

 

PLANING HULL

A surfboard should be designed as a planing hull. Most are designed with planing aspect ratios (planing width divided by planing length) similar to boats, boats being mostly displacement hulls. For optimal planing a surfboard should be relatively flat, relatively wide, and relatively rectangular. The result can be a surfboard reaching 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 planing aspect ratio of .41 is optimal for planing. Most surfboards are around .20 - .30. Lord determined through wave pool and strain gauge testing that a shape similar to an elongated body board was optimal for planing. See http://hydrodynamica.com/
Of course, what is optimal for planing is not necessarily best for maneuvering and controlling, but some will find it helpful to consider a shape with a relatively wide, flat planing area. By using a very wide double tail configuration with narrow deep twin fins, it will be found that even a board with a planing aspect ratio of .46 can be easily turned. Although wide shapes are not made for ripping and carving, many surfers will find a wider, shorter shape turns faster and with less drag compared to a long board. If a wider, shorter shape has relatively parallel rails (wide nose and wide tail) it will be faster (less drag and more lift) than boards of equal surface area with streamlined shapes (pointed nose and narrow tail).
The displacement shaped surfboard does have some advantages - a longer, narrower shape (with the same surface area and floatation) has less drag at paddling speeds and will catch the wave earlier, but as planning occurs this advantage dissipates.
Consider two surfboards of equal surface area, and floatation, and otherwise equal design - one board longer, and the other board shorter and wider. The shorter, wider design has been tested to have less drag and more lift at speeds consistent with surfboards at full plane.
Although the Small Wave Design has many of the features consistent with planing hulls, this was mostly created through years of trial and error, and not the result of reading. It is interesting to see that a design that is viewed with skepticism by most, has some scientific backing.
For more planing hull design information read the following links and possibly the entire books:
http://mypaipoboards.org/pubs/BookSummaries.shtml#Nelson_William
http://mypaipoboards.org/pubs/BookSummaries.shtml#Lord_Lindsay
Click on everything clickable on the two links. The Naval Architecture of Planing Hulls can sometimes be found for free online - it is out of print, and was about $200. in 2012 (collectors item now) - if you are not adept at math you will not understand this book - it is full of math formulas and tables. Nelson's book is also very good, but also full of math and tables. Nelson's book tends to be more practical and more directly related to surfing. He advocates wide, thick boards also. Nelson's book is no longer available online for free July, 2012.
For a rough determination of planning aspect ratio subtract 12" from board length, and subtract 1" from board width. Divide resultant width in inches by length in inches. Design in the .30 - .40 range, .30 for faster, or choppier waves and .40 for slower, or smoother waves.



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, 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 buoyant, 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 tend to 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 probably more buoyant, 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 switching from a submerged 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.

The Small Wave Design has the following negative characteristics.

1. Simply will not rip and carve.
2. Does not have the straight line tracking feeling that longboard gliders love.
3. Impossible to duck dive.
4. May have to be carried on head.
5. Relatively unstable in white water from head high plus surf.
6. Initially some riders say one of the following: "it's squirely, twitchy, corky, sliding around, or over sensitive."
6. Hard to accept, as it looks strange, and rides strange.

The Small Wave Design has the following positive characteristics.

1. Catches waves almost as easy as the longest, long boards.
2. Turns more than twice as fast and easy as a long board.
3. Goes from turning to planing faster than a long board, with less footwork.
4. Is well suited to waves which are too small for a thruster.
5. Better suited to slow, choppy surf with numerous sections requiring low drag, speed conserving cut backs, compared to longboards, or thrusters.
6. Initially, people who prefer the design say, "It's easy. It's easy to balance. It's easy to paddle. It's easy to turn."

 

CONTROVERSIAL DESIGN SUMMARY - What the surfersteve group has discovered, which contradicts conventional surfboard design. The following is not meant to insult anyone, or suggest conventional design has no merit.

Consider using all the recommended features below together, as separately problems can be cited with all of them. Separately and together they have been tested extensively for 45 years. The goal is to create a surfboard with the most flotation and planing surface in the shortest length.

1. First and foremost build with more flotation and surface area. This is the most important and most overlooked aspect of surfboard design. The vast majority of surfers are using boards which are not well suited for the average waves they surf - the boards are simply too small. If you can accept a larger board, and reject the recommendations below, you will be better off than accepting the recommendations below and choosing a smaller board.

2. Design wider, shorter, thicker, and more parallel After riding two boards with equal surface area and flotation, most riders will claim the board one foot shorter feels easier to turn, no matter what else is done to the longer board to make it turn easier. This has been shown to be true within reasonable surfboard design parameters, including the outrageous ones shown on this site. So...a board 8' x 22" x 3&1/2" with a pointed nose and tail (curved outline), and 2&1/2" of tail rocker, will feel stiff compared to a 7' x 25" x 3&1/2" board with very wide nose and tail (parallel outline), and zero tail rocker. If quick, easy turning is your priority, build shorter, and compensate by adding width, or thickness, or parallelism, or reduced tail rocker.

3. Design with a flat bottom, round rails, and deep, narrow fins, which are more upright and further forward.. Wave tank testing with strain gauges have determined the flattest, smoothest bottom contour is the fastest at speeds consistent with a surfboard at full plane. However; a flat bottom tends to slide out when turning at high speeds. Round rails and deep fins stabilize this problem, as the round rails suck into the wave face and the deep fins resist sideways drift. The drag of round rails is compensated for by using flatter tail rocker. The drag of deeper fins is compensated for by using more upright, narrower fins, positioned closer to the nose.

4. Decrease tail rocker and increase nose rocker. The result is a board which has less drag and is less likely to nose dive. Most boards have over 2" of tail curvature. This curvature causes water to wrap around the bottom of the tail, sucking it down, causing drag on the part of the board which is always in contact with the water. Yes, a surfboard with more tail rocker will turn easier, but most surfers will be stunned to discover a board with zero tail rocker, and a round rail will be noticeably faster to achieve full plane, and still be very easy to turn.

5. Proportionally increase the thickness of noses and tails - double or more than double the nose and tail thickness compared with production shapes. Part of the reason surfboard blanks thin incrementally towards the ends is simply for looks and because this is the way Clark Foam facilitated bending the foam to custom rockers - the foam would bend proportionally more where it is proportionally thinner. With molded blanks the builder will have little choice, but for those building with block foam, 2/3 of the middle thickness can be left at 1' from the nose and tail. So...a board 3" thick in the center can be about 2" thick at one foot from the nose and tail, compared to about 1" on production boards - in fact, the tail, 6" from the tail end, can be as thick as the middle, and still function without problems, even at high speeds. This, as seen in the small wave designs, will dramatically increase flotation allowing for a shorter, more maneuverable board.

6. Modify the Simmon's design instead of copying it. Although what Simmons did, in his time, was amazing, there are drawbacks to his design. He loved to experiment, and it is likely he would have modified the design, had he lived. If you watch youtube videos of Simmons' models being ridden, you will notice the riders crouching and grabbing the rail when turning in a steep area - this is because the fins are too shallow for the size of the tail, and the board is sliding when turned hard. Also; the design is too flat to fit into he curvature of a steep wave or ride over chop when forward on the board. Modify the design by using deeper fins (6" minimum with cutout type fin) and increase the nose rocker about 2" (1" increase in the last 6" of nose tip). This has been tested extensively on many models by the surfersteve group.

7. Use a fast design for a slow wave and a slow design for a fast wave. Although the small wave designs shown in this section may look sluggish, this is due to the perception of a fast board being streamlined, as with racing paddle boats. The Small Wave Design is actually a fast design, but it is more difficult to control at high speeds. It may sound contradictory, but a fast wave generally does not require a fast board. A fast wave requires a slow board that offers high speed control - a narrow, thin design with curved outline and extra rocker.

9. In conclusion: Design wider, shorter, thicker and more parallel with: less tail rocker, more nose rocker, round rails, deeper, more narrow, more upright, further forward fins, and proportionally thicker noses and tails. The result will be a board with the following characteristics: faster to achieve full plane at slow speeds, looser to twist turn, less drag in the turn, more forgiving (especially in choppy surf), less likely to nose dive, less likely to slide out, easy to balance, easy to catch waves.

Once again, this section is not intended to insult anyone, or suggest conventional surfboard design has no merit. The goal is to design the most flotation and planing surface in the shortest length. In order to achieve this, conventional design has been bypassed.

 

REVIEW OF 7' x 34" x 3.5" See Fig. 11 below.

This experimental model is a surprise. Generally a pleasant surprise in surfability. Almost always an unpleasant surprise in responses by other surfers. The initial response by most surfers looking at it is doubt. Doubt about what it is. Doubt that it can be turned. Doubt that a paddler can get his arms into the water. Although in general, I do not recommend the design, the surfersteve group believes much can be learned by going to extremes. The lack of recommendation is more because of surfers' reluctance to knee paddle, use paddling gloves, sit on the board differently, and try something very different, than because of any of the other drawbacks listed below. The board actually works well on the open face of a clean wave.

CON'S: 7' x 34" x 3.5" - Very parallel outline. 6" nose rocker. Zero tail rocker. 3.5" tail thickness 6" from end. See Fig. 11 below.

1. The following is the biggest complaint by far: 34" width is initially very uncomfortable to sit on. Riders all complained immediately of feeling as if their legs would not spread far enough. Also; transitioning from sitting to lying is awkward. These problems can be overcome by simply sitting with the legs forward or on top of the board, and pushing up with the arms when sliding the feet back. Also; if knee paddled, the rider can simply sit back from the kneeling position, with the feet on top of the board, and bisaversa. No one else was willing to make any of these adjustments. So...for the vast majority of surfers this drawback alone causes the design to be so unpleasant as to be useless.
2. Extreme width allows only the arm from the elbow down to enter the water. This reduces paddling thrust. This can be compensated for by wearing paddling gloves and knee paddling, but no one else who tried riding the design would do both.
3. Planing aspect ratio (planing width divided by planing length) of .46 increases drag at paddling speeds, compared to longer, narrower boards with the same surface area and buoyancy. The paddling speed drag and reduced paddling thrust causes this design to catch the wave later compared to a longer, narrower shape.
4. The extra width causes a feeling of extreme snap back when paddling out and being hit by white water in chest high plus surf. The paddler will lose more distance backwards with each impact relative to other designs.
5. In very choppy and lumpy surf it initially feels unstable, as the design does not plow through the chops and lumps, but instead undulates over them.
6. Terrible for lean type turning (body and board at angle to water). When leaning into a hard turn the tail will tend to slide out unless at least a 8" cutout fin is used. It will be found this design turns best with a twisting motion (body near perpendicular to water, and board flat on water). Leaning hard does not work well. 7" cutout fin is fine with twist turning.
7. Terrible in overhead white water. Terrible Stand Up Paddleboard as two strokes on one side will turn it 90 degrees.

PRO'S: 7' x 34" x 3.5" .- Very parallel outline. 6" nose rocker. Zero tail rocker. 3.5" tail thickness 6" from end. See Fig. 11 below.

1. Reaches full plane earlier (at a lower speed after catching the wave), and accelerates faster compared to all other designs. Design paddles slower, and drops in later than a long-longboard or paddleboard, but will reach the same maximum speed at about the same time on the same wave, due to the longer, narrower board accelerating more gradually (will catch up to, but not pass a longer board).
2. Turns from much further forward, and with less drag compared to all other designs - this makes it especially pleasant on the open face of a slow wave. A slow wave cutback with a longboard may take 4 seconds and may scrub off most of the speed, sometimes causing the rider to fade out of the wave. The same cutback can be done on the "soap bar model" in one second, with surprisingly little speed loss, and no need to walk the board - this makes it much less likely to fade out of the wave after turning. This is probably the best feature of the design (and all small wave designs) - low drag turning. Note: When turning on all Small Wave Designs, slide rear foot to rail, depress foot lightly, and twist.
3. Biggest surprise: Best noserider ever, even with 6" of rocker on a 7' board (out of over a hundred different wide nose boards). This is due simply to the extreme nose width. For big guys who fantasize about noseriding, something can be learned from this design - the nose has about 50% more surface area compared to the standard noserider.
4. Generally very stable. Generally very easy to balance.
5. Makes a great knee paddling, stand up knee board noserider, when using paddling gloves (Darkfin best - order 1/2 size smaller). Best used in small, clean beach break, or mushy, grinding point break. Great on the open face of a clean, but unevenly breaking wave, which requires quick, low drag turns to not fade out.

What a surprise. A design that otherwise has merit is made useless by surfer's refusal to simply sit, and paddle differently.

 

TAIL COMPARISIONS, OR DO YOU THINK YOU COULD LIKE A BIG REAR END?

The vast majority of surfboards have, within an inch or two, the same tail measurements, and roughly the same curvature. This seems to be the result of most surfers preferring lean type turning, and the ripping and carving feeling that can result. This type of surfing encourages surfers to be very resistant to moving their feet - they prefer to shift weight from heel to toe when turning, keeping the front and back foot near the board center line. It is unfortunate this type of tail, and the surfing that goes with it, are so dominate. There is merit to a wider tail with a more parallel rail - it allows for a shorter design, which, simply because it is shorter, almost always turns faster. As mentioned previously, this wide type of tail is more responsive if the rear foot is moved towards the rail and a twisting motion adopted.
Understanding what is happening to the water under the tail of a surfboard when it is being turned is valuable. Youtube videos can be accessed of surfers using a camera mounted on the end of a paddle. One video of a wide, fish tail board being turned shows a diagonal line of water running from the middle of the rear tail (at the indention), to about 2&1/2' from the tail end on the wave side of the board. So...only about half the tail is contacting the water when turned hard.
A more curved outline will turn slowly very easily and is better suited to this, while the fish tends to turn poorly when turned slowly - it requires a full commitment. This seems to be why a fish type tail tends to turn sharper than a more curved outline (when fully committed).- for a moment, the surfer is pivoting on only 1/2 the tail while only 1 fin is in the water.
Also; a wide tail board will twist turn much more easily than a narrow tail board (turn with the board almost completely flat on the water) - this is a huge advantage in small wave conditions.

Note 5: See rocker image below, and Fig 1 through Fig 13 at end of page. Choose top rocker for 30" and 34" width. Choose bottom rocker for 28" and narrower width. 3/8" measurement in top rocker should be 1/8"

Note 6: See Fig. 15 below for Fin Box position.


click on image to see full size


click on image to see full size


click on image to see full size

Do not use fins shown above if you are over 160 lbs. - heavier guys all preferred the molded 7" cutaway fins (full size fin, not cut down).

All Small Wave Designs (not including many replicas with different thicknesses) done by the Author, in the order they were built, shown below:

Note1: Fig. 1 through 15 all show radius measurements on most of the tails and noses. Fig 2 shows a nose formed from an 8" radius and three tail curves from 3" radii. Arrows touching straight lines, on the nose and tail areas denote points for center of radii. The original paper drawings have full circles shown, but these circles did not scan - sorry.

Note 2: Author, in 2012, prefers Fig. 12 and Fig. 13.

Fig 1

 

Fig 2


Fig. 3

 

Fig. 4

 

Fig.5

 

Fig. 6

Note: 11" tail in Fig. 6 is actually 9.25"

Fig. 7

Note: 9.25" tail in Fig. 7 is actually 11"

Fig. 8

 

Fig. 9

 

Fig. 10

 

Fig. 11

 

Fig. 12


Fig. 13



Fig. 15

Note: Fig. 15 - Fin box. Scale 5" = 1".

Front of fin box should be 17" on 25.5" version, and 19" on 30" and 34" versions. Cutting box to 5&1/2" length allows the fin, and box to be positioned closer to the rail, which improves response.

Plastic squeegee has 5 degree side - perfect for setting fin boxes and fins.

 

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