Rusty

In the late eighties, single to double concaves were becoming increasingly popular. And with the changing of the competitive guard around 1990, board design took an incremental jump. Boards got narrower -- very narrow -- for rail-to-rail sensitivity and quickness. A byproduct of the narrowing, the outlines got straighter and the boards actually crept up a little in length.

In order to compensate for the loss of outline curve, the bottom curve increased. Younger, quicker surfers were demanding more sensitive equipment that would draw tighter arcs. How to build drive back into these narrow, heavily bent boards? Straighten the centerline on the bottom. The concave wasn't conceived, but taken to new extremes.

Kelly Slater's tight surfing was the catalyst for the single-to-double concave, rockered-out banana chips of the early nineties. Photo: Joli/A Frame.

Some history: In 1991, Shane Herring was ranked 33rd on the ASP World Tour. Kelly Slater was 43rd. In late April of 1992, at the Coca Cola Classic North Narrabeen, the second event of the '92 world tour, this changed. Shane Herring and Kelly were both in their first ASP final together. Shane won, riding a Greg Webber-shaped deep single concave "Banana Board." Webber had been building deep singles since 1986, but didn't really gain any traction with the design until this event. Reportedly the board was specifically designed to help Herro take on Slater. Kelly went on to win his first world title in 1992. Shane finished 4th. That was his best finish and only win. The deep concave movement was on, full tilt.

Wouldn't a Flat Bottom be the Simplest, Most Efficient, thus Fastest Bottom?

I built a few 'nothing' bottoms for Taylor Knox in the early nineties. He was pushing for sub-18" (17.75") 6'2" boards . At 175 lbs, it was challenging to design him boards that would work outside of the pocket. In a nice hollow section, everything clicked. The second he was on the flats, challenging. We took a stab at flat bottoms on heavily-rockered, narrow boards: pretty vanilla. Had to put the drive back in them somehow. Concaves.

A perfectly neutral bottom is just that. It seems that there needs to be some deviation in surface and curve to help initiate release .Imagine a skimboard, sliding effortlessly across a two-dimensional playground. Next, try to imagine riding that greased pig in a three-dimensional venue, a wave. Sure, there are certain things a gifted surfer can pull off -- but the tendency would be for it to want to suck flat down onto the water at any opportunity.

Picture two pieces of glass stuck together with a little water between them. Surface tension. Introduce longitudinal curve and the line is interrupted: rocker. Introduce lateral aberrations and instability is a by-product. Wide boards generally do better with convex bottoms and narrower boards are good candidates for concave bottoms.

Another Drummer: Eev: Reverse Vee or Forward Vee

1991, Tom Curren is reigning world champ, living in France. Aussie ex-pat, Maurice Cole is shaping Tom's boards. MC received a container load of blanks from Oz that had distorted in transit from OZ and ended up with excess rocker. So the story goes. He tried to shape out the excess rail curve through the center of the blank. The railline looked familiar, but the finished blank had vee running through the midsection and was flat in the tail. At any rate, one of the first boards finished out of the tweaked foam was for Tom, and EEV (Reverse vee or Forward vee) was born.

Pat Rawson had introduced me to Maurice. Pat and I both spent some time in France during this period, shaping out of Maurice's place. As the reverse-vee gained acceptance, springboarding off Curren's popularity, the demand for Maurice's boards grew.

Tom Curren's infamous Backdoor cutback on a reverse Vee. Photo: Tom Servais

I've been getting some interest in forward vees again.

Forward vees are not to be confused with a vee that starts a few feet in front of the fins and peaks under the back fin. Since the late '60s, it's been a common practice for shapers to "peak" the vee under the (back) fin and flatten last few inches of vee, which would lift and thin the tail. This would reduce drag and make the board looser.

In an EEV board, vee starts early in the nose entry...

...and gradually increases into the midsection, deepest under the front foot...

...sometimes transitions into a double coming into the fins...

...and blends to zero or concave in tail.

Ironically, Maurice is now a proponent of very deep single concaves in his tow boards and more notably, his regular paddle-in surfboards.

Who might like the ride of a forward vee? Front-footed surfers riding a lined-up wave with some power and surface issues, like offshore winds, seem to enjoy the ride. The forward vee moves through the textured water like a butter knife. Speed banks off the front foot and nice tight gaffs off the top are almost autopilot. Cutbacks are a joy; with a well-designed EEV, when pressure is applied to the outside rail, it will bank and drive in a smooth arc back towards the energy center.

The aft portion of the board is flat or even light concave, heavily bent and thin. The geometry through the fin area puts the top skin and bottom skin close together so it flexes more readily as well. These design elements all combined makes for a board that drives exceptionally well off the front foot and has potential for tight, smooth direction changes off the back foot.

What about the Finish on a Bottom?

Back in the day when glossed and polished was the standard finish, there would be conditions when the waves were so glassy, I could feel my board sticking to the wave face (surface adhesion or tension) like two flat pieces of glass with a little water between them. In different parts of the wave, the front rail would slide and lack traction at inopportune times -- like driving a car with bald front tires. In the early '70s, Skip Frye introduced me to sanded finishes. For me, the first time I rode a board with a fine-sanded finish as opposed to a polished gloss, the difference was very apparent.

Every once and awhile we get treated to a light offshore from the right angle that creates the perfect texture on the wave face. It's a session when the wind causes a ball bearing-like effect on the wave face surface. The board seems to ride simultaneously on a cushion of air while still remaining in contact and control in the water. It's a magical feeling. Loose, free, fast, and in control. Nature's contribution to an ideal surfing boundary layer. I'm not even going to get into laminar flow, boundary layers, and different types of drag -- that's all on the Internet if you're interested.

Why not try and create a bottom that has that feeling? Willis Brothers did. They borrowed from the golf world and put dimples in the bottom of their boards...PhaZer bottoms. Good idea, but a nightmare to glass!

Over the years there have been countless debates about the ideal performance (not cosmetic) finish. A directional, longitudinal 400-grit finish seems to get the nod.

There may be zones on the bottom and rails that are candidates for alternative sanding patterns, like fine crosshatching to promote neutrality and other zones with deeper, directional grooves like micro-channels (Peter St. Pierre, Micro Grooves) to manage flow and increase traction.

Speed-coating products from the boating and aircraft world have been repackaged and offered up to surfers many times over the last few decades. On the grand scale of things like yacht racing and fuel efficiency on planes and jets, fractions of a percent makes a difference. Surfboards...? Flat out speed efficiency isn't always the main objective. Overall handling and feel in a variety of conditions is far more important. Keep your bottom and rails clean with a Scotch Brite pad or something similar works fine. There are plenty of surfboard specific cleaning products on the market.

While not part of your board, leashes add a lot of drag. If you have never gone unleashed, you might enjoy the sensation of taking off the handbrake.

Venturis or Bonzer Bottoms:

I've covered these in earlier blogs. Think about a spray nozzle on a garden hose. The wider the pattern, the less you feel push back. Tighten the cluster so the spray coming out of the end of the hose is more focused; the more focused the stream of water is coming out of the nozzle in relation to the diameter of the hose, the more the nozzle feels like it is moving away from the directed flow.

Technically, venturis need a closed environment. But the basic principle seems to work on a surfboard bottom. The water isn't really being compressed so much as it is being redirected and focused.

Venturi concave.

With Bonzers, the longer side fins contribute to the process. In addition, they add more drive and hold. On a regular three-fin setup, with a venturi type concave, you will probably feel a fair bit of lift but a little less hold or bite than you would with a double concave that extended out to the rails. On the upside, the rails will probably feel a little less grabby in weaker surf.

Taylor Knox is a fan of the venturi.

The Campbell Brothers definitely deserve kudos for contributing to the foundation of modern bottoms.

PT and a Bonzer bottom. Photo: Surfresearch.com.au.

Back to Simple: Single Concave
With variations and deviations on the bottom of a surfboard, waterflow is changed. The idea is to do it in a productive way. Design the bottom to direct the flow based on individual needs. I'm a big fan of subtle. The greater the deviation or change in curve, the more opportunity there is to incur drag and inconsistency in performance.

Bottoms that have a strong degree of influence on waterflow (i.e. 6 channels, Venturi) tend to be specialty boards, unless other design elements are brought into play to offset the big personality. Smaller fins, breaks in the outline, going shorter, more rocker, etc are examples of ways to offset the directional tendencies of these types of bottoms.

The basic thinking on how or why single concaves work is that the flow of water is directed through the center of the board, through the fins and out the back of the board. Less water is spilled out the sides, more lift created. The rail has more curve than the center. The water travels with less resistance down the straighter path. Put the board on rail and the arc tightens.

At lower speeds, the single concave is a relatively free and unfettered bottom that provides a lot of lateral forgiveness. The steepness of the concave wall out towards the rail contributes to a faster reaction time, a more sensitive feel. It will allow the rider to do a series of quicker, flatter turns to generate speed. At higher speeds, the walls of the concave adds bite to the turns on the inboard rail and the water sheeting off the bottom is deflected off the outboard concave wall and is directed aft.

Is there anything else that that the concave does to increase performance? Does the concave add area? Yes, but it is negligible. All things being the same, take a stock 6'2" with a typical 3/16" concave running through the bottom and increase the concave to ½". Area added? Approximately 5 square centimeters or about .78 square inches on a board that has a total of 3355 sq centimeters or 520 square inches: less than one 10th of a percent. Make it 1" deep (that's deep!) and the increase is about 10 cm sq or 1.55 square inches: 1/3 of 1 percent more area.

With a deep enough concave, the argument can be made there is actually less wetted area, less drag, because it is acting more like a catamaran than a mono-hull.

Singles are good for relatively low volume, low area boards. The amount of lift and speed the single concave generates is more easily managed on these types of boards. Put a deep concave in a longer, wider, thicker board and it will fight back. Too much lift, too hard to control.

Conversely, higher volume, bigger boards can be made a little more user-friendly when certain types of convex features are incorporated. A little release on the forward part of the rail, a light vee between the feet -- features that help initiate turns and keep the front part of the board from catching.

In other words: The power and the shape of the wave dictates the bottom shape -- depending on your approach.

For average surf, which usually lacks in power and line, we're looking for a board that is short, responsive, and makes the most of the weak wave energy. Wide (planing area) and thin (sensitive, increased flex) boards with concave (lift and hold) bottoms are a common solution. The concave will typically start in the entry or somewhere roughly 12 to 18 inches from the nose and gradually increase through the center and reach its deepest point between the feet or just in front of the fins. It will transition fairly rapidly into a flat or light vee in the last few inches of the board.

Most small wave designs typically incorporate a fair bit of tail area. To keep the wider tail free from sticking on tight turns, slides, or launches, a little tail release or vee seems to help.

Single con with a split off the tail.

"Single Con" is a catch-all name...most actually have the single splitting subtly going past the front fins with either a light spine under and through the rear fin(s) or flattening and lifting off the last few inches.

To create tail vee, the rail-line must accelerate more quickly than the centerline off the back end of the board. This helps to tighten the turn arc as the water moves past the fins.

Small, weak, lined-up surf opens the menu on equipment: short, long, everything in between, and a variety of bottoms -- whatever suits the palette.

But in a clean, hollow, compressive beachbreak, a shortboard (fit and reaction time) with a deep single concave running right through the tail offers full tilt carve, linking tight radius turns. More carve and less slide but the board curve needs to fit the wave curve.

Deep single.

A long, running pointbreak with some nice hollow bits? The lines on the board can stretch out a bit, the concave not as deep, smooth transitions, longer lines, a little release in the tail to bleed speed when needed. A double barrel (concave) vee: the stringer is above the rail, subtle but slightly elevated. Rounding the spine of the vee lends to smoother feeling transitions rail-to-rail.

Pointbreak board: double barrel (domed) vee.

Off to the tropics? Shallow, clean, double concaves are usually a good solution. Still get the lift and the bite from the concaves but with some directional enhancement from the spine of the vee. High-speed rail-to-rail transitions are made easier because of the lateral break in the bottom.

Reefbreak board.

Note: the rail and stringer are flush, not a vee, but a double concave

Ready to tackle some big waves? You're looking at a longer, drawn-out board designed to deal with dispersing energy -- managing it in a different way, 'cause there is a surplus of power. For decades, entry usually incorporated vee and/or roll to part the not-usually-smooth water on the way down the face. The mid-section of the board usually is flat or slight concave for planing speed. The last third typically has a light vee that flattens behind the back fin. In recent years, more gunsmiths seem to be running vee the front 2/3rds of the board and going flat or double concave through the fin area. This type of bottom helps the board to penetrate and drive down a windy, bumpy face and commit the inside rail to a long steep wall, minimizing drag out the back.

Big-wave board.

Average people and average conditions:
For roughly 20 years, the single concave has been a go-to bottom for most board builders. Easy to build. Easy to ride.

After all is said and done, there many more options than just a "single con" for the everyday stuff. It comes down to understanding the whole package. If there is a certain bottom or feel you're interested in; if you're looking for something new and fresh to challenge you or add some fun back into your surfing, an experienced shaper can help you by combining all the elements needed so that the sum of the parts yields the performance you are after.

Happy surfing.

-R.

The last few blogs I've covered Bob Simmon's influences on modern design, and an overview on rocker. A natural segue would be a little history and discourse on bottoms.

Here's a short list of some bottom contours that have been utilized over the last 40 years: Vee bottom. Spiral vee. Hulls. Tri-Hulls. Tri-plane Hulls. Bonzers. Venturis. Double-barrel vee. Clinker bottoms. Channel bottom. Six-deep channels. Four-deep channels. Belly channels. Curved-belly channels. Phazer bottoms. Micro Grooves. Triple con. Double concave. Reverse vee. Step tails. Hydro hulls. Hydrofoil. Jet bottom. Slot bottom. Double-deep concave.

And...the single concave. Why single concave?

A little background: Concaves in surfboard bottoms have been around since Bob Simmons introduced them in approximately 1946. Some big-wave guns from the late '50s and early '60s have concave in the bottoms, all the way through the tails.

But for the most part, surfboards up until the late '60s had convex bottoms. Sure, there were plenty of nose concave designs for noseriding, but concave in the back half of the board was more the exception than the rule. In 1966, 1967, longboards started to shorten up a little and vee bottoms were introduced. The panels on either side of the stringer were relatively flat.

Bob McTavish circa 1968; pretty futuristic looking board: double concave entry feeding into a vee bottom.

Vee helped these still relatively high-volume, wide boards, to tip over, and carve a shorter arc on rail. The problem was, in more powerful surf, when turning these deep vee bottom boards, they had a propensity to tip over, run on one rail, and lift or climb right out of the water. They would spin out.

Bottom turn or spinning out? '70s SURFER cover.

As the boards evolved over the next couple of years, they got shorter, and eventually narrower, and the deep vees became passé. The late '60s shortboards still had some genetic residue from the longboard era: slightly rolled noses with a lifted rail up front, but the rails were firming up in the middle, laterally a little flatter, and the tails were down railed with shallow vees. Hulls still enjoy a strong and loyal following with the folks who frequent lined-up pointbreaks with almond-shaped pockets

Classic '70s single-fin bottom. Photo: Brody

By '70 and '71, rails are down all the way; nose-to-tail, bottoms are much flatter, and the vees are starting to get dished out into something called "spiral vees." The elevated spine of the vee still helped to initiate turns and provided drive and direction. By dishing out or hollowing out the vee panels towards the rail, more bite, or hold, was created. Water was routed through the troughs and spiraled out through the tail. These types of bottoms were the norm for a few years. There was lots of experimentation with wings, stings, and other types of template breaks in conjunction with smaller, secondary concaves exiting through the outline breaks.

Aussie shaping legend Terry Fitzgerald was a major proponent of these "Flyers".

Fitzy explains: "The jump came in the winter of '72. My Hawaiian influenced boards just didn't have enough tail area to skate over the flat spots at Narrabeen. So, I ADDED wings (or what we called flyers). The idea was that by adding the wing to the rail it would add more planing area, but you'd still have a narrow tail for in the pocket and bigger waves. The 'wing/flyer' had to be pinched to allow the rail to stay in the wave and run you higher as well (á la Bunker's idea). But, the wing also gave you a break point for snapping out of the lip. So, three pure benefits: More planing area to get across the flats; pinched wing to stick in the face and ride high on; a break point in the rail to snap off the lip on. [Tested in Hawaii that year and then launched in December '72, January '73 in Australia.]

Fitzy's ad from Tracks magazine.

Fitzy continues: "Wings were not something you created by cutting a piece out of the tail of your board. They were ADDED to the rail line/foil and planshape, and pinched to have minimum effect of rail-line entry but maximum effect on planning area when flat -- plus, the increased ability to run high and hold a high line.

"I've always been a concave addict (right back to an 8'9" that had a concave from nose to tail that I had custom built in 1967), so when the pinwings I was riding started to get stuck in the lip, I went back to an old trick off putting a concave in the pin behind the fin. You still had rail line, but a vacuum when flat (almost a swallowtail effect) so going rail-to-rail was a damn sight easier. The vees were always spiraled (rolled and curved), so changing the panels back to concave was an easy feed."

Before the shift to multiple fins, some of the best single-fin surfing was being done on channel bottoms. Six deep channels. And during the '70s, there was a lot of tinkering with bottoms, trying to gain speed and traction. Short, wide boards were loose but required longer, deeper fins to keep them in the water. The longer fins had a lot of frontal drag -- they slowed the board down. Narrower boards were quicker and required less fin but were somewhat impractical for most average surfers in average conditions. So, unless you were a very light surfer, or riding good, hollow waves all the time, the narrower boards were liking owning a Ferrari but being stuck in city streets most of the time.

The early '80s saw fairly short, wide boards with bottoms that still had remnant features from twin-fins and single-fins. Fairly flat under the front foot with vee running through the back third of the board.

Late 70's Canyon double wing, double barrel twinnie

With the advent of the three-fin surfboard, the search for increased traction and drive, while minimizing drag, was put on the back burner. Bottoms started to change. Check back next week for part two...

"I may never retire, but at least I've been semi-retired my whole life." Paul Elder is one of the elite few who has made a life out of doing what he loves. And what Paul loves is art. Paul is an exceptional painter and free hand artist that is inspired by the life that surrounds him: surfing, traveling, and fishing - his passion for these activities is undeniable in his work. You have probably seen Paul's work several times and have never even realized it. If you are a fan of Rusty Surfboards you have definitely seen his work as Paul designed several of our board icons over the years including the Piranha, the Desert Island, the Predator, the Toad, the Cat Fish, and the Slayer.

The Ballast Point Brewery artwork is also the brain child of Elder, everything from beer bottle labels to tap handles, he free handed them all. Some other notable clients of Elder's includes: Bloody Decks, Bulky Boy, H&M Landing, and a handful of other small local businesses...

Paul has a secluded art studio where he does a lot of his work and the quaint retreat is riddled with colorful masterpieces. Upon entering Paul's studio it quickly becomes apparent that he loves what he does. In addition to the stunning finished products gracing the walls, there are other works in progress and tid bits of inspiration scattered about. Photos from an old Baja camping trip are tacked to the wall. Concept sketches are lying here and there. Dried paint in a plethora of colors line the edge of his easel. Everywhere you look there is art.

Do not be fooled though. Paul is not just an artist playing the role of the fly on the wall and portraying what he sees, he is a very active participant in the arenas that inspire his artwork the most. As an avid surfer, fisherman, and a long time traveler, Paul has built his life around his lifestyle. Paul has spent time in Indonesia, El Salvador, and Mexico and Thailand, where he spent his formative years in elementary and middle school. The nature of being an artist allows him to create his own schedule, leaving plenty of room for fishing and surfing trips. Also, being the hands on kind of guy that he his, he will often dabble in the construction process of his gear. For example, he made his very impressive spear fishing gun from scratch - not an easy feat to accomplish. Once again, to prove that he is not just an artist and a craftsman, Paul graciously opened his freezer to share a plentiful helping of fresh white sea bass that he caught himself the day prior.

What a life? Travel, surf, fish... and then paint it. Perhaps he should be a teacher too, because we should all be taking notes.

Text and Photos: Brody

Ryan Bingham is pretty much the Josh Kerr of country music... With youth, enthusiasm, a bit of craziness (as a former bull rider), and a whole heap of talent Bingham has catapulted himself into the lime light of the music and, as of recent, Hollywood scene.  Bingham has been having quite the impressive winning streak with a Golden Globe and now an Oscar to his name for Best Original Song, "The Weary Kind (Theme frome Crazy Heart)".  The modest musician stopped by the Rusty Surfboards Factory last week for a one on one shaping lesson with Rusty and he took to shaping quite naturally. He is obviously of the artistic breed and understands how to create something custom to fit a certain situation, much like how he collaborated with Crazy Heart Producer and Co-writer, T Bone Burnett, to design the perfect song to fit the mood and vision of the film...

Bingham arrived at the Rusty Surfboards Factory, said his hellos, and wasted no time hopping into the shaping bay for some hands on training with Rusty.  Not even five minutes had passed when Rusty exclaimed, covered by shaping dust and muffled by his mask, "You've gotta check this out! He's taking over in here!"  The singer was quick to exchange his guitar for a planer and was elbow deep in foam, making swift passes across the blank with the confidence of a veteran.  As an appreciator of the good old days Bingham decided to shape his board the old fashioned way, using templates and a hand saw to cut the blank.  Laid back tunes from Rusty's iPod echoed through the shaping bay, but were occasionally drowned out by the sound of the planer. Step by step Bingham crafted his dream board under the guidance of Rusty.  When it was all said and done a beautiful custom round tail shortboard lay in the racks and both Rusty and Ryan sat back, masks around their necks, and eye balled their work, grinning from ear to ear.  I couldn't tell who was more stoked, Rusty or Ryan.

Text and Photos: Brody

Rocker has traditionally been labeled as the single most important component or design element in a surfboard. But it's unrealistic to try and isolate one aspect of a surfboard -- a complex combination of compound curves -- and claim that one component as the single most important design feature. It's the marriage of all the curves, hopefully working in harmony to produce the magic.

When it comes to talking about surfboards, we think -- and shapers tend to work -- step-by-step, in a 2D world and by the magic of process, it all gets woven into a wonderful 3D, functional, sculpture.

How many of you have bought a new board that looks like it's the one -- magic -- but it's not quite right? It's fast as you'd want, but doesn't turn, or it's super loose but bogs on the flats -- or it works at Spot X and dogs at Spot Y.

Interior curves
The centerline, the spinal chord, is the easiest to quantify. The rail rocker and all the transitional pathways radiating out from the spine towards the perimeter (outline) are infinitely more difficult to measure and quantify. The relationship of the perimeter rocker with the center is what determines bottom shape.

Wireframes provide a glimpse into the complexity of how all the curves interact.

Can you ride a door? Over the years in a few films and videos, we've seen some pretty good surfers take a stab at it. Maybe a narrow one with soft rails and a little flex might be the go. Alaias are flat but they bend. So do bodyboards. It's so nice to be able to adjust the curve of your ride to fit the occasion. If it's thin enough, depending on what it's made of, you can bend rocker into it as you ride. What's good about a bodyboard? You bend it to fit. Cheating!

Flex can be and is built into a surfboard. Then there are issues about the quality of the flex; how efficiently will it return to its original shape? Where do you position yourself? How hard can I, or should I, press and when, and where do I need to stand?

So rocker is not the defining component. But -- unlike all other design elements -- it is in a state of flux. Your outline, thickness, rail shape, fins, and fin position won't change as you ride a wave but your board rocker, your bottom curve will, depending on construction, weight, force, etc.

The juxtaposition of rail-rocker and bottom rocker create bottom contours. Image: Steve Coletta/ naturalcurvesboards.com

Shapers worry about fractions of an inch, but in reality, blanks sag and bend on the shaping racks, or the glassing racks. Other factors come into play: during lamination, resin shrinking as it goes off can pull rocker into or out of a blank, or cause the blank to twist slightly, resulting in asymmetrical rocker. Epoxy runs roughly 2% and polyester about 6%. Reaction time or how hot the batch is affects the shrinkage too. Or, how a board is stored can affect the final outcome. Rocker can be affected in the process of building a board after it leaves the shapers hands. What we shape and what ends up as the finished product always has a variance.

Rocker on the front end of the board is cosmetic, to a large degree. The first six inches or so. The entry, the guts, and back third, the business end, is what really matters. The overall flow is nice from an aesthetic standpoint and to certain degree, performance. But really, you could lose the front three, six inches and still end up with something that gets the job done. Miss the back third, the command center, by a few hundredths of and inch, and it becomes an issue. Good or bad, it's all subjective and heavily dependent on the waves you ride and how you want to ride them.

How do we measure rocker?

Most shapers I know use some sort of straight edge placed on the center point of the bottom. The blank or board is placed bottom up on racks, the top of a trash bin, sawhorses, or some thing that provides a reasonably stable, level surface.

Photo: Sean Brody

Mark the center of the board. Use a beam as a tangent. Crude, but if you find a light firm straight edge, you can create a close proximity to a tangent. Some shapers will use the straight edge of a half template. I like three-sided aluminum window track. If you can find something with about ½" walls, eight feet long and straight, it's gold. It's light, rigid enough, and doesn't influence the blank with its weight or sag within a reasonable degree. An eight-foot incandescent bulb actually works pretty well too.

Photo: Sean Brody

Shapers use a very light, one-finger touch on the rocker beam. When measuring a finished board, incurring flex and distorting the measurement isn't as much of an issue. Using the light finger press, in theory the blank or board could be on its side or upright. It shouldn't matter if the beam is pressed against the center point. If you are using something shorter than your actual board length, like a 6-foot beam (easy to find at any hardware store) mark the center of the beam. Place it on the center of the board. Press lightly and measure a point within the half-length of the beam, like the 12-inch mark. Establish what the rocker is at that point and then find something about ½" to ¾" thick you can use as a shim underneath the beam, slide it underneath the beam until it makes contact, then slide the beam to the full length of the end of the board and make sure your reference point is consistent with the previous measure, then go ahead and measure the rest of the board. When I'm shaping longer boards, like guns, longboards and SUPs, this is the method I use to make an 8-foot beam cover anything up to almost twice its length

Putting your board belly down on the ground to measure rocker doesn't work because the balance of the board is affected by the distribution of mass so your net number might be in the ball park -- but the (tangential) end numbers that most shapers use will be off.

Measure the tips and one foot in from both ends and you will get numbers that are probably consistent with in 1/16th of an inch to what your shaper is coming in with.

Tape comes in handy so you don't have to mark up the blank or board. Photo: Sean Brody

Since the early days, many shapers have used rocker templates. The female curve that fits to the bottom of the board. Curves that fit that middle third, or half of the board. Curves that fit the entire length are more difficult to generate and require many more physical copies for a full spectrum of equipment. The guts of the board are critical -- eyeballing the interior three to four feet of a board takes a very experienced eye. The flow on the ends is fairly easy to pick up on with the front foot of board somewhat cosmetic, the back foot or so, extremely important.

Photo: Sean Brody

Rocker templates for the entry to exit, or the middle third, or half of the board are critical. The curve through the few feet of the middle is very important because it influences the numbers out towards the ends. A little change or variance in the mid-section magnifies the numbers, proportionately, as the measurement moves away from the center.

If a spreadsheet was compiled from a few dozen good boards of various sizes, I believe the numbers for mid-section curve would be remarkably consistent.

Adjustable "rocker jigs", or a tools to capture the bottom, or deck, curve and transfer it to another blank or some material to make templates, have been around for decades.

This rocker profile jig was designed and built by Stan Pleskunas 20 plus years ago. Image: Rusty

There are similar jigs available through some surfboard-building suppliers.

These are very useful tools that will nest onto the bottom of your board -- or any board that captures your interest -- and holds a flexible baton or strip of plastic in place with a series of adjustable spars. This type of tool allows you transfer the curve to some sort of template material or a blank you or your shaper is working on. These tools are great because they really get a good impression of the transitions.

The flow out of the exit of the board is something that should jump out at any experienced shaper -- and to a certain extent, a surfer who has owned more than handful of boards or a least looks at a lot of boards.

Looking at and seeing the differences:

Place your board in front of you, tail in your hands, bottom up. Slowly raise and lower the board so you can see the transition from the very end of the board up to the mid section. Move it off to one side and raise and lower it a few more times. Centerline. Rail line. Do this a few times to get an impression. Then go through the same process with any other boards you may have or get together with a few friends and check out their boards as well. The more boards you look at and try, the more you will start to understand what the different curves look like; you will register finer increments of change. You will start to make the connection between the arc you are looking at and the arc you make on a wave.

Shaping Rocker:

Ironically, electric "power" planers, the shaper's primary tool, are something borrowed from carpentry. A tool designed to take down thickness whilst keeping the surface as flat as possible. It ends up they can remove a lot of foam and are good at blending curves. An experienced shaper feels the curve underneath the tool; blending and smoothing the transitions as if the tool were the actual water flowing over the surface.

Carving in rocker by hand with an electric planer is an art and a science.

Computers have given us the capability to reproduce the things we want to with a very close degree of tolerance.

I have lots of stories about good accidents in the hand-shape world: boards that get bumped and need some post-shape cosmetic surgery, or some sort of dyslexic mishap that results in a magic board. On the flipside, computers do what they are told. So if a shaper wants to get creative, he can. And, if by some good fortune or well thought through idea, the board works, it's repeatable.

Magic boards shaped by hand are an act by the accidental purist. Or an accidental act by the purist. If a draw-knife had soul, a Skil 100 Planer is the Holy Grail, where does that place the CAD program and CNC machine? It's a logical step forward and the reason why overall board quality and consistency has improved greatly in the last 10 or so years. More than ever, understanding what you need or want is so important because the numbers part of it is so doable with CAD design.

There is no right or wrong. The role of rocker is to fit the curve of a particular wave you are going to ride and the lines you want to draw.

Try to visualize a cross-section of the wave, wave height, shape, and contemplate the speed it s traveling and the power behind it and create a curve to fit it or create a curve that has an element of resistance, plus or minus, so that you might have leverage or control to personal standards that fits that curve.

At the end of the day a 5'2" fish would probably nest right into the guts of a 10'4" gun.

A 6'8" for Pipeline, if cropped to 6'2" for Big Rock, might be too flat. The wave and the arc you want to draw are the key defining elements for the arc or radius of the curve of your board.

Every wave is different and every surfer plays it with his or her own touch. Take any given spot on any day given day and each and every different surfer will draw slightly different lines.

Flow and balance: A brief history of Rocker

Since the early days of longer boards, a surfer visualized riding waves a certain way and a shaper would blend the curves to make the vision happen.

As surfing evolved, and the lines drawn became more diverse, the curves of the boards evolved. New understanding of how all the elements complement each other: rocker, width, outline curve, foils, bottoms, flex, fin size, placement, angles. It's a give and take. Change one facet to try to achieve a particular feel and there are many ways to compliment or enhance the change so other performance aspects don't get compromised.

Mini-guns of the late '60s and early '70s saw heavily kicked noses to make the drop but straight, narrow tails for drive and hold. These were single fins; with wide points up and narrow, straight, tails; outline curves reflect the bottom curves.

Brewer was one of the most influential shapers during the shortboard (r)evolution. Exploring different types of rocker early in the shortboard era, many of Brewer's designs inspired shapers around the world, myself included. At the time, this ski influenced "Disc" was very forward looking...in retrospect, an example of an imbalanced curve.

Reno Abillera and his blue disc.

Mid- to late-'70s; Parrish and Barnfield take modern single fins to a new threshold: Beautiful, parabolic, clean uninterrupted rockers.

Geoff McCoy challenges template proportions and gives us all a glimpse of the future. He pulls in the nose and widens the tail, rethinking the proportions needed to surf more intimately than ever. Surfers want to be as deep and tight as possible.

1981 Simon gives us three fins.

Pat Rawson takes his Brewer foundation (he also credits Barnfield with teaching him how to measure rocker) and makes early tri-fin guns for the North Shore that turn heads and set new standards for performance in THE testing ground. Part of the magic is a break in the rocker line in the control center...between the feet...the business end of the board.

"Staged rocker" or curves with breaks still have their place. On longer boards the change in curve creates a fulcrum for turning. The breaks are usually located in conjunction with an outline break -- a "hip". The more exaggerated the break is, or the interruption of flow is, the looser the board becomes. The downside is an increase in drag.

In more modern designs, there are still plenty of shapers who use rocker breaks but they tend to be very subtle. With the much lower relative volume of modern designs, the rider isn't as much of a passenger and can overpower the board more readily. The role of the fulcrum has diminished with today's thinner, narrower, shorter boards.

The '80s saw more curve in the back of the boards, drive provided by the tri-fin setup. Front fins allow for wider tails, create lift and hold. The 3rd fin off the tail provides drive and additional hold.

Early '90s rockers are pushed to what are arguably modern extremes.

Templates change, less outline curve, gunnier, thinner, bendier, more rocker; boards are deeper in the water, committed to rail arc and flex. With more rocker, drive has to be built back in somehow. Straighter outlines, deeper concaves, bigger fins, straighter fin angles. Narrowness lends to quickness from rail to rail.

Boards have crept up in length, largely due to the increase in bottom curve in the '90s and early into this millennium.

You could chop off a couple of inches from the nose and a half an inch and change from the tail and have a shorter board that still rode the same or possibly better without all the baggage on the extremities.

I stopped someone at the beach the other day. He had a typical performance shortboard from a big label. The front three inches of his nose were missing. I asked how long it had been like that. "A month or so." Can you tell the difference? "Not really."

What are the symptoms of a board that doesn't fit?

In small, gutless surf, getting on top of the water, planing and linking sections is always a challenge. The solution is an increase in area and volume and a decrease in bottom curve.

Conversely, as you step into venues that have more powerful, hollower surf, generally speaking, you'll want more curve. Visualize the curve of the wave, its power, and the length of ride or arcs you are looking to draw.

Flow is important.

The more the water has to bend around a curve, the more drag incurred: more curve requires or enables shorter arcs, quicker response from the rider, less glide, more effort. The rhythm of the wave and rider need to be in sync.

Balance of the curve

Most boards have a very similar curve thought the midsection.

When turning a board, a good solid rail turn, it's important to visualize the waterline arc of the board and see how it's going to run through the water. An imbalance at either end of the board will create drag. If the front part of the curve doesn't feed the back part of the curve efficiently and creates conflict on the line you might be trying to draw: the board doesn't flow or follow itself through turns.

Too much rocker in the nose won't prevent pearling or poking if the tail is too straight. The back part of the board needs to fit the canopy of the wave.

A low entry may paddle well and catch waves early but it might not fit the curve of the trough of the wave and it will also set an arc (lack of curve) that fights the change in curve in the back of the board.

-A 9'8" gun may have 7" in the nose and 3" in the tail

Greg Long winning the Eddie on a 9'8" x 10 3/4" x 20 1/2" x 10 5/8" x 3 1/8" by Christenson. Photo: Klein

-A 6'8" pipe board may have 5.5" in the nose and 2.75" in the tail
-A 6'2" hot-dog board may have 5" in the nose and 2.5" in the tail
-A 5'6" fish may have 3.8" in the nose and 1.05" in the tail

Some CAD programs will let the users "ghost" in another board for comparison.

The end numbers are fairly common knowledge or at least somewhat consistent from shaper to shaper. If your shaper doesn't provide them for you, it's easy enough for you to start tracking your numbers. Use of a straight-edge and measure 0, 3, 6, 12, 18, 24 from the ends.

Width and thickness are fairly easy to track as well.

More and more shapers are using machines these days and there are some shaping CAD programs that are available online in a beta version for consumers to play with.

Numbers are good. These beta versions of shaping programs will allow you to play with curves and start to understand transition numbers and sequences that flow. Keep in mind, however, the proof is always in the water.

One of my biggest shaping influences was Bill Barnfield. In the late '70s, Bill taught me the importance of tracking numbers. Lot's of them: numeric control long before CAD shaping.

Ask for your numbers from your shaper and learn to measure your boards.

Check out your friend's boards.

Building a base of reference helps you understand what your needs and solutions might look like.

Your next magic board might be the one already under your feet -- with a ¼ inch change in tail rocker.

Talk to your shaper and learn to speak his language. Knowledge is king and if you put in the effort, the reward is yours.

Happy surfing
R.

One guy mentioned he was confused about wings and fuselage and how that relates to surfboards. I used wing shape as an analogy so one can get a feeling for how shape affects aspect ratio from familiar airplane wings.

There were a few requests for a diagram. This is very simplified but should shed some light on the discussion. It is important to keep in mind that as the speed changes the wetted area changes. The slower you go the more area is needed to plane/support the weight. As the area increases or decreases with speed, the wetted area aspect ratio changes as well.

I think it is almost impossible to know what the wetted area is at any given time. It might be possible to get a reasonably accurate estimate of the wetted area/aspect ratio if you knew the speed at any given moment. Add to that the directional changes of the flow which changes the span value and you get some pretty serious variables that are way over my ability to understand.

This is math emulating art so there is a lot of room for discussion about the nuance of the influence of aspect ratio on surfboard performance. Given the vagaries of wetted area size and shape it is probably best to stick with the known outline area if you want to use aspect ratio as a data point for surfboard design. However shapers have been doing a pretty damn good job for a long time without worrying about all this crap. Another consideration is the fact that it is very likely that one aspect ratio might be perfect for one guy and a total dud for another.

Jay Davies conducting a bit of R&D. Photo: Brody

Probably the only way to get a handle on if aspect ratio is a valid data point would be to do a study of one rider's boards (good and bad) to see if there are trends that can be used effectively to predict how aspect ratio affects performance.

In the end aspect ratio is simply a description. We might find that aspect ratio is as relevant as "blue boards go faster than red boards". Until all of the design factors within a surfboard can be quantified this will remain an intellectual discussion. If that discussion reveals that aspect ratio is valid or not as a design data point we will have learned something. Hopefully it will be justifiable ignore all the math and just go surfing.

Last blog, John Elwell, a friend of Bob Simmons during the last five or six years of his life, shared stories from this great innovator. Here is Elwell's discussion on the planing hull:

Aspect ratio is a proper width and length ratio. Naval architect Lindsay Lord said the most common factor in a good planing hull was the width in the stern. If you divide the width into the length you'll get the Aspect Ratio. It will be a decimal number. Good numbers are .3 to .5. Wing design uses this depending on how much it is designed to lift with a power plant. With extraordinary amounts of power, a lower aspect number will work. (At Windansea, Simmons went to the shortboard because of the more powerful wave. He already did this in powerful shorebreak at Hermosa.)

In summary, there is a good ratio between length and width. Things too narrow don't plane well and shapes that are too wide are handicapped also. Examples are the U2 spy planes that are like gliders and can fly high and sustain themselves, as well as longboards that will pick up on big, fat waves and have increased resurgence at low speeds. These features also work against these shapes at high speeds. The tow-in boards are adapted because they can get a low aspect ratio up to planing speed where a paddler can't.

Archimedes displacement steps in for hydrostatics for the "plate" as it is called to support the load it is to carry. In other words, the optimum plate must float enough to not hinder lift...or too much, like paddleboards. Simmons was able to reduce a lot of extra weight by reducing flotation to a minimum. The boards in static position just barely floated with the tails squatting in the water, which is the attack angle. Moving a planing hull slowly, such as with a surfboard gets the kinetic energy (water flowing) to get initial lift to get it over the "hump" to plane while paddling in.

Tow-ins break the rules by having a power plant take you up to planing speeds to stay in the wave. Then as Lord says, "Everything changes." Pointed sterns start to drag. On surfboards when the pressure is on the inside rail to the wave the dynamic trans-pan flow comes across the bottom of the lower part of the hull. It is directed there by the monohydrean shape we call the "rounded rail" that is making the top of the rail low pressure and the bottom dynamic high pressure. The result is lift by the kinetic energy (moving water) that is being deflected. The surfer is controlling the pressure by the amount of weight he exerts on the rail from his feet in the right position. Planing is described as skimming on water. Lord says planing hulls adjust themselves with speed, so much that they can fly dangerously out of control at higher speeds in conditions that can be too rough causing cross waves and chop. The camber nose or turn up really helped surfboards from pearling -- an early problem with the old boards that no longer was a problem after Simmons.

Aspect ratio, put into use. Photo: Slavin

The old planks did not plane or turn well because of too much flotation, too much weight, and the wrong shape of rails. People were told to drag a foot to turn to angle the board. That ended with the Simmons' boards. All boards thereafter copied the foiled rounded rail, but changed nose and tail shapes to their own liking. No one knew what they were copying or doing. Simmons did not talk to very many surfers, nor did some of those surfers listen to him.

The modern board has some type of rounded foiled rails. There is still a lot of confusion of what the outline should be. But there shouldn't be if the surfboard makers knew how the electric strain gage works to identify shapes that have resistance. But aesthetics still win out in marketing. Today, so many people copy what works in surfing but are not quite sure how it works because there are a number of complex things working. One of the most important things that Simmons said and simply observed was that a surfboard really is going almost as fast sideways to the beach as it is going forward. He identified a surfboard's trajectory and designed a board to do that. What he did was not the last word in planing hulls as he was constantly changing and improving on what he did. What he did was on solid ground. As Curren once told me, "It was too bad he died, he may have come up with something better."

The summation of Lindsey Lord -- the MIT naval architect who wrote the book on the Naval Architecture of Planing Hulls, who used the Bernoulli equation, and tested his study with the Simmons strain gage for exact data -- said, " There is nothing revolutionary in this because one thing leads back to another. In other words, there are links after links to other known principles." And further more, "These things we did are from solid information and only the beginning."

I must smile on the definition of "flex". It is wide-open to some degree but there is a solid base and flex would fit into refining and improving the basic findings. There are restrictions but keep in mind that, "The sea is a hostile and ever-changing environment."

The parameters as Simmons saw it as a scientist was, "We are really not going that fast; you just think your are." He was right because waves only go so fast. He worked on reducing drag, with suitable size and flotation for the load of each rider, then attacked the enemy of planing hulls -- resistance, mainly eddy flow drag, and excessive fin(s) -- through Lord, hydrodynamic understanding, and his own observations and data with strain gages.

What he had and did for his time was remarkable. Proper aspect ratio was of course a key factor. To make it simple, there are important parts to the whole. Although as Lord said, "You change around a little but everything else is a compromise." Which was apparent for better planing because it keeps the water under pressure and directing by the monohydrean rail for sudden and dynamic release, for lift making the hull lighter. Changing your weight deflects the board for turns and trim. The rail reduces pressure on top and increases pressure from the bottom, and it also tracks and holds the board in the wave unless it gets too steep. This application is unique to waves from standard planing.

We can follow the history of surfing. We look back and see small Hawaiian or Oceanic types of plates. They were used for different types of surfing. All these designs were done by "rule of thumb" -- simply, what works is copied. They had no mathematics or language, and only the materials available. The variable is, of course, the rider's skill. Some rider's can ride anything. Dempsey Holder use to say, "A good surfboard rider can ride a door." That is what it has been. Surfboards got screwed up from old Hawaiian shapes with "planks" and "paddle boards". Flat decks and U-rails have too much weight. Paddleboards are surface shapes and have serious drag problems planing. This all had to be sorted out.

We started out in '47 riding borrowed paddleboards and planks. They were dangerous and impossible to ride well except for the gifted few. We asked our mentors and every one advised, "Get a board that floats." Usually surfers picked a board with nice grains and a shiny finish. No one knew how a surfboard worked...until Simmons came along. Bob defined surfing as planing and surfboards were supposed to be planing hulls. Simmons snarled and gnashed his teeth, "Paddleboards are not." He was more specific and despised pointed tails and tails under 10 inches, but favored wider tails for quicker lift. Soon, his adversaries, which were a few of the ignorant and jealous, started to generate vicious hearsay about wide tails, spin out, nose pushing and so forth.

Simmons would snarl, "Go someplace with better waves! We are really surfing on our rails." He was right and it was too difficult to explain to the general population found at the beach. He was referring of course to Bernoulli and Lord's research and basic hard knowledge of aero and hydrodynamics.

Others over the years without really understanding all that he did and meant have said, "Simmons was way ahead of the pack by light years."

Stan Pleskunas is one of those quiet understated, highly-achieving, mad scientist surf dudes. His shaping machines were state of the art in the late '80s -- Channel Islands, Linden, Nectar, and Rusty all used them. He designed a line of shaping hand tools, which are still used by many shapers today. Stan also worked with Lis, Greenough, and countless other visionaries on boards, sailboards, machines, and fins. His Fumunda Marine Products are globally distributed.

He goes further into Aspect Ratio for us:

The "whole" surfboard plan form is distinct from "wetted area" plan form. That said, it stands to reason that overall plan form relates in a general sense, to wetted plan form if the shapes considered are more or less conventional surfboard shapes. Another thing that seems to be overlooked is the rule (which is set in stone) that it takes a given amount of area to plane, a given weight at a given speed. Gravity and weight are the constants where speed and area are the variables in this rule. This is sort of the bedrock or foundation that all other factors are based on. To be more concise, the slower you go the more area you need to plane a given weight.

The next thing to consider is the power available. If you look at a modern jet, the wing plan form is decidedly inefficient or low aspect ratio. This is because of the fact that there is essentially unlimited power to push the jet forward.

Digging deep with a Simmons-inspired hull design. Photo: Slavin

On the other hand if you look at a sailplane the wings are long and narrow which have extremely high aspect ratios. The reason for this is there is nothing but gravity powering a sailplane so it has to be very efficient. To recap: low aspect ratios are less efficient. Higher aspect ratios are more efficient. In aeronautics, efficiency is measured in the ratio of lift to drag.

Throughout this rant we are assuming that the areas for both high and low aspect bodies are the same and the weight is the same. So low aspect ratio wings will have a much steeper natural glide path than a high aspect wing. A jet might have an unpowered glide path described as 2-to-1. That is, it goes forward two-feet for every foot it falls. A sailplane might have a glide path of 20-to-1 or it goes forward 20-feet for every foot it drops. The reason is the differences between the drag that low aspect and high aspect wings have. Remember, in this case gravity force/weight and area is the same for both bodies.

This might seem a bit complicated but it is not. Lower aspect ratio wings are more swept back. Higher aspect ratio wings are more perpendicular to the flow. What that means is at any point along a low aspect ratio wing, the flow is in contact with the wing for a longer distance than on a high aspect ratio body. This offers more opportunity for the flow to develop turbulence and increase drag, so it has more drag for the lift it generates. On a high aspect body the flow is in contact with the surface for a shorter distance so it has less opportunity to develop turbulence hence less drag for the lift it generates.

So if we have two wings of exactly the same area carrying exactly the same weight, the low aspect ratio body will require more power to go exactly the same speed as the higher aspect body. And if we try to relate all this to surfboards, let's start with the assumption that the wetted area will more or less reflect what the overall plan form aspect ratio is. Keep in mind that the rule of speed, weight and wetted area still applies.

Let's take a 6'2" x 19" board. Steve Coletta's outline (which is what I have to work with) has 1060 square inches. The span is measured as the width of the shape or perpendicular to the flow, parallel to the stringer. In this case the span is 19", the square of 19" is 361. The span squared 361, divided by the area of 1060 is .3405. .3405 is the aspect ratio of the outline shape.

That same board scaled to be 9'8" X 20.5" has an aspect ratio of .2349. This is a substantially lower aspect ratio than the 6'2". The gun has an aspect ratio, which is only 69% of the 6'2" board.

So the question begs to be asked: why does a gun go so much faster than a shortboard if higher aspect ratios are more efficient? First, it has to do with amount of power available to push the board forward. Just like the jet that might fly at mach 2 the gun has a heap more power available. The gun on a big wave has more power to tap than a shortboard on a small wave. It is certainly arguable that a shortboard will go faster than a gun on a smaller wave more suited to the shortboard. All things equal, especially the available power, efficiency wins over all. Otherwise, we would all be riding 10-foot guns on three-foot waves. A 9'6" longboard designed for smaller waves will be much wider which will push the aspect ratio up considerably perhaps even equal to the shortboard's aspect ratio. Or put it this way, the 9'6" board would have to be much wider and have much more area to have the same aspect ratio as the 6'2", which would end up looking like a longboard not a gun.

The next obvious question is why not ride a shorter, higher aspect ratio board in big waves where we have all that power available to go that much faster? Again, for the same reason a jet has low aspect wings -- it is all about control. The flow laying on the wing for a longer distance makes the jet more pitch stable than the sailplane. It has more drag but the advantage of lower aspect ratios is it does not pitch up and down or pearl and stall as easily as the high aspect wings of a sailplane. With all that power, the jet, just as the gun, must be controllable especially in the "pitch" plane. So you are dropping into 15-foot Sunset with three-foot bumps coming up the face, the lack of relative efficiency of the gun to the shortboard is of minor concern compared to plowing into bumps or getting launched off one. Besides there is so much power to tap who cares if the shortboard is a touch more efficient? Control is the key to riding bigger, bumpier waves.

This is really simplified but the basic premise of this argument is correct, in my opinion. This is more or less proven by the fact that smaller waves require more efficiency and they are generally ridden on higher aspect ratio boards. The same is true for big waves where longer lower aspect ratio boards are ridden in big waves. Today's shapers have it sorted out -- just look at what they prescribe for different wave conditions, it all pans out. One thing that is very hard to get a handle on is the power that a competent surfer can add to the equation. When a guy starts pumping and the board begins to flex a bit and he un-weights, the energy he is imparting is substantial. This profoundly affects the efficiency and ultimate speed of the board. This is where today's shapers have made most of the improvements in design. This is especially true for specific riders who can accurately communicate their feeling/desires in a design to the shaper.

This treatment does not take into account rocker, thickness, rail shape and a myriad of other design features that make a complete board. However, using aspect ratio as a common denominator for board measurement/design might be a very useful (if overlooked) tool to tune surfboard shapes with. Using aspect ratio as a measurement will be an empirical process but may really help those who have had a family of boards designed with CAD software. Area measurements, which are critical to calculating aspect ratio, are easily known from CAD drawings.

Where is the next frontier in board design? I think it will be in the quantification and control of flex. This has not been done and cannot now be easily designed for. Given the variability in shapes, materials and construction techniques it will be a long row to hoe to get flex sorted out. When a guy gets that "magic" board, that "magic" is flex, in my opinion. I could go on and on about flex but that is entirely another chapter.

Every year Rusty spends time on Tavarua Island in Fiji, home of the infamous waves Cloud Break and Restaurants. Rusty will be spending five weeks on the island surfing, stand up paddling, fishing, and conducting some research and development on a few new board shapes...

This years trip is off to an interesting start; the day Rusty showed up, Restaurants started filtering in a few sets and he wasted no time tackling the long left hander on his SUP.

A few days into the trip Rusty put an end to the meager fishing season by reeling in a 200+ lbs. Black Marlin. After the initial ice breaking catch the ocean has come to life, providing yellow fin tuna and dorado daily.

However, it has not been all waves and fish... The island of Tavarua underwent an emergency evacuation due to a tsunami warning issued after an 8.8 earthquake hit Chile. Everyone on the island was rushed onto boats and sped over to the mainland where they headed for the hills. Rusty, the rest of the island guests, and the Fijians all hung out on top of a small mountain in an old World War II bunker hoping for minimal impact, but preparing for the worst. The tsunami was scheduled to strike Fiji at 10:04 am, but luckily the tidal wave never came...

Tavarua Island is full of surprises; keep your eyes on the Rusty Blog to see what the next couple of weeks has in store for Rusty...

Photos and Text: Brody

It's no secret that surfboard design requires a certain bit of hydrodynamics. And while some of you were snoozing in physics class, early board-builders were figuring things out so today's modern shapers didn't really have to. Leading that early charge was Bob Simmons -- an eccentric dude, who didn't care much what people thought of his off-the-wall concepts. However, Simmons single-handedly looked at the board's planing surface and made it the forefront of shaping.

Richard Kenvin on a Simmons-inspired model. Photo: Scott Sullivan

San Diego surfer Richard Kenvin is making a film about Simmons called 'Hydrodynamica' and offers the following:

After the longboard era ended in the late sixties, surfers pursued a performance ideal focused on deep tuberiding, tight-radius carves, controlled slides, and finally, vertical turns in and above the lip. This performance criterion has dictated the evolution of the shortboard over the past 40 years. The desire to perform precise vertical turns and make controlled micro-adjustments on the face and in the barrel brought about a narrow, stiletto-like board with continuous outline curve, lots of rocker, and a canted fin cluster designed for holding power and instant release up the face. All of these design innovations make today's incredible shortboard performance surfing possible. The dreams of the late sixties have come true, and there is no argument that the modern shortboard is a functional waveriding machine that allows for spectacular surfing.

That being said, this shortboard performance ideal comes with a price, and the currency that pays that price is drag. Quick lift, paddling power, glide, planing speed, and trim have all been sacrificed on the altar of maneuverability. For the strong and agile or for those lucky enough to ride clean, powerful surf on a regular basis such drag-inducing design elements as ample rocker and narrow curvy outlines have more benefits than drawbacks. Even so, surfers are always looking for new sensations, and in recent years many of us have been exploring designs from the past that originated long before the contemporary shortboard. Wide, low rocker, high aspect-ratio designs like the fish don't allow quite the same performance levels as shortboards, but they do set us free, more or less, from paying the debt of drag associated with ultra-rockered, narrow designs.

This growing movement towards experiencing "alternative" boards like the fish is evidence of a widespread desire to be freed, at least occasionally, from the shackles of over-specialized contemporary design. In fact, these "retro" boards are now influencing shortboard design as rockers mellow, outlines get straighter, and boards get wider and shorter. As the design pendulum swings back in favor of wider and flatter, it seems we are in for interesting times. With minds opening along these lines, shortboard performance is about to take a leap forward in a new direction. Relaxed trim and planing speed will be possible on very short and maneuverable boards, and the dreaded "Huntington Hop" will be eliminated from our repertoires. All along the surf history timeline the prophets of width and planing speed have appeared and blown our minds: the Paipo riders of Hawaii, Bob Simmons, George Greenough, Steve Lis, and though we try to deny it, bodyboarders like Mike Stewart and Danny Kim have all brought us a message we too often fail to heed. With evidence of the virtues of flat and wide (and finless flex!) displayed right before our eyes our tendency to stubbornly deny those virtues in favor of convention is quite remarkable.

When considering wider, high aspect ratio board design it becomes impossible to ignore the work of Bob Simmons in the late 1940s and early '50s. By the time of his death in 1954, Simmons had brought his dual-finned hydrodynamic planing hull design to a state of fulfilled refinement. But planing hull surfboard history really begins with the traditional finless boards of pre-contact Hawaii, particularly the short, wide Paipo board and the longer and slightly narrower Alaia. These ancient surfboards are extremely fast due to a hydrodynamic design that allows for subtle flex, very efficient trim and planing and hardly any drag.

In the mid 1940s, scale models resembling Paipo and Alaia type planing craft were tested in Hawaii as part of an effort to improve military powerboat performance. And in 1946, naval architect Lindsay Lord published the results of these tests in a study titled The Naval Architecture of Planing Hulls. Lord proclaimed the performance benefits of wide hull designs and also acknowledged the challenge of incorporating them into a seaworthy vessel. Modifications and compromises were necessary to achieve this, and the same holds true for surfboard design. Before long, Simmons obtained a copy of Lord's report and referred to it when designing his first planing hull surfboard in 1948. He also studied the work of the Daniel Bernoulli, a mathematician from the 18th century who had articulated the basic principles of hydrodynamic lift in a study published in 1738 under the title Hydrodynamica. Simmons then began effectively combining ancient planing principles with modern hydrodynamic theory to arrive at an entirely new type of surfboard.

Simmons was able to harness the planing powers of the traditional finless boards by designing a Bernoulli-inspired elliptical rail that, when guided by a shallow keel fin, allowed his boards to accelerate out of turns and carve on a rail with unprecedented control. The Simmons rail generated dynamic lift and required a fin to function properly. He kept his tails very wide for planing speed, and he placed a keel on each outboard rail near the tail. He used minimal rocker to reduce drag, and minimal curve in his outlines to maximize trim speed. He broke the outline slightly in the back third with a "bump" for release, and he rounded the noses of his boards and tilted them upwards in order to create lift through displacement when paddling into waves and negotiating steep drops and chop. This innovation became known as a "spoon". The lifted angle of the spoon is sometimes mistaken for rocker, but the actual riding surface of the board is quite flat.

Simmons' boards are perhaps more relevant today than at any other time in surfing history. With the advanced CAD design programs now available it is possible to reference the original planing hull concept and blend it with contemporary designs to make better boards. Fin placement and bottom curve can be tweaked and adjusted until a happy medium is achieved, with the goal being a very short board that paddles well, skates, glides, and trims, all without sacrificing maneuverability or control in the tube. Riding a Simmons-inspired planing hull and discovering its place in surfing's past and its relevance in the present is a rewarding experience for surfers of all ability levels.

+++

John Elwell was friends with Bob Simmons the last five or six years of his life. He was in the water with him at Windansea the day he died. Elwell has a book called "Surfing in San Diego," which is a great historical overview. Elwell elaborates on 'The Coming of Simmons':

First, we heard rumors of new boards that were the rage of Malibu in 1948 and early '49 and of Simmons. He showed up here at IB in '49 when I met him. This guy had power of "presence". You could feel it when he walked in the lifeguard station. I once felt like a wind passing and he went behind me unseen. The guy wore a glitter of fiberglass dust and clothes of resin. His plaid wool shirts were faded and well worn, and he wore deck shoes -- never any socks or underwear. He was poorly groomed and shaved and spoke in short, hard one-liners, snarling or cackling laughs. He was no nonsense, almost unfriendly at first. He was all business and a busy person about to die young. When something was bad...it was a disaster!

Chris DelMoro, using his hull. Photo: Peterson

We wanted some of his boards but he was not ready to make boards for everyone. We had to get the wood and he would shape for $15 and we would sand to his directions and supervision in glassing. It would take a while -- like almost a year. The good times were watching him shape and carefully asking him questions. He would like to tell special stories of surf experiences. He would blurt out stuff that we would have to think about.

After his death, Morgan and I would talk about this. He said we wouldn't ever know what he was talking about and what all those calculations were on his hydrographic charts. He talked about a sea break off SF called the Great Break. Then, at times, talked about 100-foot waves off Chile that he would need special rubber suits that were not yet developed and small bail out bottles of oxygen.

At 16, it was like talking to someone like Buck Rogers. 'Is this guy for real?' Then there were boomerangs -- that he called deadly weapons -- and ping-pong championships. All connected again, we would find out later through Bernoulli. My relation to Simmons is that we became good friends surfing together and watching and listening to him shape in the station. I admired him, not knowing he was a brilliant math student, engineer at Douglas, a machinist, master boomerang-maker and thrower, ping-pong champion, and power bicyclist. He was an accomplished athlete of special skills and endurance sports. He had a badly injured arm from a bicycle accident that almost killed him. He almost went down at Hermosa from a blow from his board. But he was not a cripple, or a "surfer who could hardly swim," as Quig described him. His arm was wired together without being able to rotate it and it slashed the water. He made mile swims off the Sloughs and no one worried about him.

I was surfing with Simmons the day he was killed and was the only one with him when he took off late on a big wave and slipped on a new, poorly-waxed board. He was surfing brilliantly that day after returning from the North Shore in the winter of '53. He made a new board in '54, the same configuration but improved the attack angle so he could take one-stroke and no-stroke take-offs. His boards were just about perfectly balanced and he would check them on a sawhorse and note the center of gravity. I think this is very important! When Morgan told me that we might never know what he meant, I started to turn over stones with his family and friends to put the puzzle together. Simmons was indeed way out there. Even back then, he talked about predicting surf from sun spot storms that heat the equator which causes the El Nino.

Check back next week for part two of this subject -- Aspect Ratio.

You are invited to come paddle with Rusty, demo his custom SUP boards and find out about his TEC models coming soon from Boardworkds. Meet us at La Jolla Shores on Wednesday, Feb 3, 8-10am. Click here to enlarge the image below...