Talking Design With Rusty: Grading the High-Tech Backyard Shaping Project

Photo: Aaron Chang. Text: Mark Anders

For Surfline's last review, they took a look at a very cool (and free!) surfboard shaping software called BoardCAD. You can even download your virtual board design to a computerized shaping machine which will cut it for you, allowing the average guy with zero shaping experience to design his own boards.

While the software is intuitive and relatively easy to use, designing a surfboard that'll surf worth a crap is still a challenge.  I've spent some time monkeying around with BoardCAD until I ended up with a 6'4" small-wave board that he thought looked pretty dang fun.

But I've been warned that what you see on the computer screen and what pops out the other end of a shaping machine are often not the same thing. So before we waste a perfectly good blank cutting my board, we asked shaping legend Rusty Preisendorfer to proofread my design and grade my shape.

Now I realize just how lucky I am to be given this opportunity -- I mean, having Rusty grade your surfboard design is akin to having Tiger Woods rate your swing, or Kelly judge your frontside hack. But it's also very stressful. As soon as I hit send, and my design was hurtling toward Rusty's inbox in SoCal, I was nerve-wracked.

A couple days later, my report card arrived, and here's what Professor Preisendorfer had to say:

Outline: B-
"Overall looks good. The little Toad/Rocket wing on the tail is cool. But usually I will do the subtle features like that by hand until I really settle into a design. Don't get too caught up in detail, especially in the tail."

Deck: B
"The deck is a pretty benign thing, really. But I think you might want to take some of the dome out of the deck, and go with a little less volume."

Cross Sections: B
"Cross sections are like taking AP classes, so you did a pretty good job. Overall the deck looks a little crowned to me but that's a personal preference thing."

Bottom: C-
"You missed the mark here pretty hard. You didn't do enough homework there. Rocker is a pretty subjective thing, but you'll want to flatten it out a little bit--2.86 inches is quite a bit of tail rocker. For a 6'8" Pipeline board I might use 2.7 inches or a little more. For a 6'4" hotdog board I would drop it to 2.15 to 2.35 inches max."

Overall: B-
"Pretty impressed with your first design."

Teacher's Comments:
"Remember, you can always subtract foam but you can't add it back. Leave yourself a little extra foam, especially on the ends of the board. For the middle 60 to 70 percent of the board, let the machine do a lot of the magic, but err on the thick side especially on the last 30 percent on the nose and tail. Keep in mind that you can shape in detail: fine-tune tail outline, rail thickness, tip thickness, concave. So leave yourself a little wiggle room on early designs until you get a feel for how the design on the screen translates into a cut."

So my homework assignment is to try to fix the problems that Rusty pointed out on my 6'4". Then, I'll send it over to a computer cutting service and get my blank mowed. While you obviously won't have the luxury of Rusty proofing your own designs, he says most guys who operate computer cutting services are experienced folks who would be happy to help look over your design before it's cut. Some will charge you for their time, others may do it gratis because they just want you to have a good experience and come back to cut more boards at their shop. Either way, "be respectful of his time, and be humble," recommends Rusty.

Humble, that's the easy part. I've found that designing a surfboard -- either virtually or by hand -- is an inherently humbling experience that's bound to make any surfer better appreciate the time and skill that goes into creating a truly great surfboard.

For the full archive of Surfline's Surf Gear Reviews, click here.

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Talking Design with Rusty: Bottom Line Part 1

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.

01_mctavishBob 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

singlefinClassic '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.

80s_twinfinLate 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...

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Talking Design with Rusty: Off Your Rocker

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.

compWireframes 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.

picture-1The juxtaposition of rail-rocker and bottom rocker create bottom contours. Image: Steve Coletta/

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.

board_measuring1Photo: 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.

rocker_measuring2Photo: 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.

backfromnoseTape 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.

rocker_measure2Photo: 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 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

klein_eddie09_0093Greg 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

abs_machineSome 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

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Talking Design with Rusty: Aspect Ratio


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.

_mg_0948Jay 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.

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FAQ: Can You Give Me Some Advice on Finding a Board for a Bigger Surfer?

Moby Fish

Big Cat

I'm interested in the Big Cat or Moby Fish. I was wondering what size you would recommend for a guy like me: 5' 8" and 200 lbs, maybe more with my wetsuit. I'm 57 years old and still in good shape because I snowboard, surf, and rollerblade. I have been surfing since 1965. Had a lot of boards. I want a board that paddles well, but still rides well. I was thinking Big Cat 8' x 23" x 3 1/4". You guys are the first site I've found that gets the idea about boards for a bigger guy. Typically, I have always had a problem with shapers that recommended a smaller board. Usually they were guys 135 to 150 lbs and couldn't relate to a bigger surfer.

Rusty's Answer:
The Moby is more of a small wave design with some range that will allow the rider to enjoy most conditions up to head high. This is a good design to contemplate if you want something other than a longboard for the small days. They paddle like a board a foot longer yet still retain the looseness of a board a little shorter.

The Big Cat is a much more versatile design. It is an update to the Desert Island with much more all around performance. A great candidate for the 5 fin convertible box setup.

PS: The shaper is big and he is 56 years young.

Click here to go to the surfboard site and check out the Moby Fish and Big Cat!

Talking Design with Rusty: Quadrophenia Part II

Part one of Quadrophenia was focused mainly on what makes a good quad. In part two, Rusty interviews notable shapers, surfers and designers on the history of quads. Enjoy. --Ed

tom-carrollPipe Master and former World Champ Tom Carroll on a serious quad in the eighties.

Simon Anderson on quads:
I'm looking to make a quad that performs like a thruster -- in other words: predictable and connecting smoothly through turns. My 2009 quad has a twin-type plan shape with flat nose entry but a lot of tail rocker with deep vee through the back half of the board and at the swallowtail, deep single concave cuts through the front half of the bottom with a double cutting thru the vee to the tail.

The fins are more clustered than last year's model. I use normal thruster side fins and 1/8" smaller double-sided foiled-back fins both at five degrees -- the forward fins point to the nose tip and the rear fins point straighter up the board.

This style of board for me works great in waves that lack a little bit of power and I find that I can do power turns off the top thru a section with a flatter or weaker face that actually feel like thruster turns on a more powerful wave.

My quads are designed for the most part for small waves, from one to four feet. Average surfers can surf these boards in bigger waves up to six feet and have a lot fun because of the extra speed and looseness off the top. But in the end, the quad is essentially a well-behaved twin fin and the trick is to harness the wild element -- as much as possible -- associated with this type of design.


There's a lot of speculation on who made the first quad. I imagine quite a few designers were searching for ways to build more drive into twin fins and expand their range. Glen Winton is one the first surfer/shapers that I know of who made a four fin. Certainly there were others.

Greg Mungall talked to me recently about the impact of Simon's visit. Greg had a hot-selling twin-fin model with Nectar. Nectar's focus quickly shifted to the Thruster. With Simon's back-to-back wins at Bells and the Coke, the design was more than validated and in heavy demand. Greg asked Gary McNabb if he could do a double-wing swallow three-fin. Gary declined but offered up, "Why don't you put four fins on a board?"

Greg did and took it to his next pro event in Japan.

Late in 1981, Australian shaper Bruce McKee made his first quad and hasn't looked back. His Mission Quattro is a nearly three-decade long commitment to refining and evolving the four-fin surfboard.


Bruce McKee on quads:

I found it interesting the way in 1981, the Thruster was first created, then packaged and heavily promoted by the mags and pro surfer community. It was definitely a major advancement, a great mix of needs finding a solution. A new concept with an iconic statesman to represent it. To me, though, it was just one solution; before the end of 1981, I had commenced what I called: "Mission Quattro."

I saw the first four-fins and quads as twin-fins with baby stabilizers on the back and nothing more. Just as I saw twin fins with baby stabilizers on the back for what they were. Were they also Thrusters? No. You could add a number to the fin combo but that's just a label.

I found that Thrusters had flaws -- not that anyone wanted to agree with me. To say otherwise was heresy, a sacrilege. Maybe it was just my shapes, but I tried other's boards too. Maybe you can have a full quiver of shapes, make a narrow-tailed board to aid the tail fin's penetration and hold, larger fins, etc. But that meant that board shapes and tail widths needed to be customized to certain size waves, as a golf bag has a range of clubs for each part of the course. But I wanted an all-around club, or at least greater versatility out of one. Nursing turns on a Thruster or double setting bottom-turns wasn't attractive to me, so the logic appeared to me to be that having four fins of similar size on the rail, should hold in better than a thruster. To combat the twin-fin image quads had, I placed larger rear fins than the fronts on the board, plus it had a four-channel bottom, which was popular at the time. (I had never ridden a traditional quad, which I knew would ride like it looked -- like a Twinnie with baby back fins.)

curren_slabbertWhen the legendary Tom Curren tore into legendary J-Bay for the Search movies, it was a little known fact that he was riding a quad shaped by Bruce McKee. Photo: Lance Slabbert.

My first-ever bottom turn on that first Quattro board had me feeling that "Eureka!" moment -- like an explorer finding the Fountain of Youth, my own Holy Grail. Acceleration, speed, hold, foam-climbing ability, was all there. Problem was, the world was starting to pulse with Thrusters, and my quad or what I called a Quattro, named after the car, was promptly classified as a lost cause, and sympathetically smirked and snarled upon by surfing's new "Thought and Design Police."

Although my first Quattro had the fin cluster too far forward, it still hung in and I could thump the bottom turns. If I got my foot right back I could go past vertical. I knew then that the system would be amazing for guns. I could have the fins forward and it would be loose with no fear of spinning out. I stuck a baby back fin on the tail for a quick fix but knew that I just had to move the cluster back a bit to get the feeling right.

My first boards from 1981 to 1988 had 10% larger rear fins than front, but on my migration to Europe via Hawaii, I took with me a board with all fins the same size. It was way too small for the conditions I found (a 6'5"), but I got enough waves and big turns in to have complete faith in the direction I was following.

I ended up on the north coast of Spain in the Basque Country. Soon I linked up with the Pukas and factory Olatu where I was resident shaper for 12 years. I managed to make a bunch of Quads, but, as is true in many industries, there are companies that push for innovation and others that want conformity that brings safety. Many of the surfing industry's shaping gurus had me pegged as a heretic -- a poor fool who had lost his way; obsessed (not dedicated) with trying to make others swallow the medicine. According to them, Quads were caustic medicine.

quattrogunsAussie expat quad-o-phile Bruce McKee and his eighties and nineties quad guns.

During a surf session at a lefthand point break, a friend visiting from Oz asked, "Why don't you put the back fins closer together more like a thruster's center fin?" I remember saying, "But there's more drive when they're on the rail." With longboards, the fins are way forward, so if you move the rear fins forward you tend to follow the rail so the back fins have a big spread between them. This means that you have to do big body gyrations just to get the board to come down off the lip after running across the wave face. The problem was that the lower side fins engaged too late and the board felt like it was stuck on one tack still wanting to go up the face. What a center fin does is it re-centers the board between turns and enables it to easily be redirected back down the face.

So the words of my friend stuck in my head and, later, I couldn't believe how stupid I had been for not analyzing his words more carefully. His idea was totally logical in that, by bringing the rear fins closer together, they reacted faster in re-centering the board while still maintaining drive. I found that too close loses drive -- so there was a happy medium there that combined the best factors of both.

The early Tom Curren quads had the rear fins close together because they were squashed in narrow tails. They worked due to correct combined fin size, flex toe-in, etc., but needed a back foot overpowering the back fins to get a good pivot off the top when at speed. I had veered off the good track while trying to cluster the fins, not realizing the relevance of the distance between the rear fins to each other.


Nearly three decades later, Bruce McKee is still a staunch advocate of the four-fin. His M5 is a design with five boxes. It is what he calls "The System of Truth" and adds, "The ball is your court."


Back to the early quads.

News drifted back to us in Southern California of Simon's victories at the Coke Surfabout and big Bells. Time to have another look at Simon's three-fin board, the Thruster. Most designers and shapers on the planet began working, in earnest, to understand and evolve the design.

MR had dominated professional surfing for four years riding a twin-fin, winning consecutive world titles from 1979 to 1982. 1982 was a year of transition. Some surfers still rode twins in small surf and would switch to singles in bigger surf. Many had changed over to three fins. Cheyne was still riding singles in all conditions. Glen Winton was starting to have competitive success on a four fin.

[1982 final rankings: 1. MR (two fins); 2. Cheyne Horan (one fin); 3. Tom Carroll (three fins); 21. Glen Winton (four fins)]

By 1983, most competitive surfers had moved to three fins, with the exception of Horan and Winton. Tom Carroll took home the first three-fin world title. For the next quarter century the three-fin dominated the competitive landscape. Simon's design has been further refined by shapers the world over and has become, arguably, the single most important, enduring surfboard design of all time.

Several generations of surfers have known only Trifins.

Who remembers this magazine cover?

1984-surfer-4-fin-cover050Larry Bertlemann. Quad. Aerial. 25 years ago.

He shaped it with George Downing. Larry had been working on twins and added rears to add more drive. The previous winter he told his friends that he was going to "fly." This shot is at V-land on a 5'10" and LB claims he was 230lbs. at the time. He also mentioned that the fins were 747s. (Originally called 747s now called 757s.)

rainbow_757This is from 1983.

Why do evolutionary branches of design get choked off, atrophy, only to be "rediscovered" and nurtured into a new life?

As a relatively new sport, the majority of the surfing audience looks to its competitive heroes and icons to validate what is good. A one-design mentality keeps the equipment very homogenous. It's rare to find a top competitive surfer that will cross the line for fear of prejudice -- at least in the line of duty.

Concurrently, there is another side to the surfing culture that participates in, not a sport, but this kinetic art form; the quest for newness empowers these artists to walk down a different road, indifferent to the opinion of the masses. Herein lie the eclectic seeds of change and variety, freshness.

Why didn't Bob Simmons' twin-finned board take a linear path to Mark Richards' four world titles?

I asked Carl Ekstrom recently what was the first three-finned surfboard he could recall. His answer: "In the late '50s I built a board with a tail that was too wide, it kept spinning out. I couldn't afford to make another one so I stuck two small fins on the rail outside the main fin. It fixed the problem."

In October 1980, Simon crossed paths with Frank Williams. Frank, a journeyman shaper, had worked with Geoff McCoy, Barry Bennett and other notable Sydney boardmakers. Simon ran into Frank as he was coming out of the water at Narrabeen with a board that was essentially a twin fin with a strange little "half-moon" shaped fin on the tail.

Simon asked him what the third fin was for, and Frank told him, "It helps make it more stable."

Simon's instant response was, "I'm going to make it real stable!" In that moment the Thruster was conceived in Simon's mind.

Glen Winton, in all probability, may not be the first person to have put four fins on a surfboard but is credited with the design. In a recent Nick Carroll/ASL interview, Glen actually claims to have started with six fins with the intention of knocking two off after getting a feel for the board.

"I put six on with the aim of picking one set to knock off. I actually won a contest on the six. That's how four fins were invented -- by knocking two off 'em."

mcintyre_libia_seanbrodyShayne McIntyre, four-fins and fancy-free in Liberia. Photo: Sean Brody

Nick Carroll weighs in on quads:

Pros pooh-pooh them for a few reasons. One is that their favorite boardmakers by and large haven't yet "conquered" the design, they've just sorta dummied one up as a semi-Fish or whatever, which just doesn't cut it at a high-performance level. Another is that they have very little trouble with their current equipment -- a refined single concave thruster is a pretty damn good board and it'll go wherever they want, so why fool around? I think that is changing at the moment, a benefit of Kelly taking a few risks -- although the conventional wisdom is that KS was blowing it, riding 5'4"s etc. in heats, a lot of the pros saw him riding those little things in freesurf sessions and were pretty much blown away by what he could do. It's opened up the doors for shorter boards and increasingly quads I suspect.

Me, I got fascinated by the four-fin thing about four years ago after being tormented by TC for a coupla years on it, he is an Early Adopter! They'd irritated me in the past because I'd always felt there was a real loss of center-line feeling in the board -- that it's good to know where the center of the board is when finishing turns, especially because it allows you to flow swiftly into the next turn, and without a center fin, there was just a sort of void, which caused the board to respond slowly at the end of turns. Like whatever speed you were gaining out of losing the back fin, it was negated by that weird clumsiness at the end of a turn.

The old twinnies used to make up for it with that mega-vee through the fins -- nothing like vee for giving you a sense of a board's center-line! So I got one made that was a bit radical at the time, 5'7" with a straight-ish rocker, double concave with a little spine through the fins to give it a sense of the center, template pulled in to conventional hi-performance width at the tail, and back fin set in a bit closer to the stringer. Surfed it a couple of times but then along came those carbon rail epoxy boards and I kinda forgot about it ... dug it out again six months ago and I couldn't believe how quick and sorta savage it was. Have got a few since then and I'm beginning to wonder if in time the quad's advantages might push the thruster aside a bit. It's just taking time because the fin set is so riddled with potential fuckups. People tend to use too much fin overall for one thing.

Why the heck are they faster, well I don't know if all of 'em are faster, but they FEEL like they are, because there's no center fin dragging on entry into a low angled turn like what most normal-level surfers do as a matter of course while running along a wave. That back end freedom is pretty seductive.

Three fins, they're less complex, they surf in arcs and snaps along with longer carves and they recover better in airs and slides, they love single concaves which still feel like the best bottom going, they're easy to tune using a fin system. But they can feel draggy next to a quad, especially for a surfer of average ability, and there's not much left to explore about the design, it's there and it ain't changing the sport any more.

Four fins, they run fast and free, their ability to run longer turns mean they can be shaped short (i.e. a 5'8" quad can ride similar sized surf to a 5'11" three-fin) which makes for some very different lines, they're excellent tuberiding boards, done right they give you heaps of feedback while you're surfing them (you can feel a lot more underfoot than on most conventional three-fins). They can feel awkward on quick direction changes and they don't all like to surf in arcs off the top, but there's still quite a few questions in the design and that makes it exciting I think. The quad could still change the sport a bit.


Pat Maus, a teamrider, came to me five or six years ago and wanted to build four fins. I hadn't really made any since the early '80s.

Pat Maus on quads:

Yeah, the first time I got on a quad the waves were waist-to-chest-high, and all I had with me was my tri-fin squash tail. Nathan [Fletcher] took one look at my board, and in typical Nathan tone gives me the, "Psssssss! Yer still riding three-finners? You should try that quad right there."

Nathan was kind of curious to see how someone other than himself could make the board work. But the last time I saw a four fin -- I think Glen Winton was carrying it! Anyway, I loved the board after the first wave, and since Nathan had a new one, he gave me that board. It was a 5'7" bat-wing quad, shaped by Cole.

The how and the why they work so well? Well, ask any person that's tried a quad and nine times outta 10 the first thing they mention is how fast they go. Then come the people who love how easily they can do turns and control the board. You see, with a quad, the moment you set your rail and go front side or backside, you already have two fins grabbing the face. That allows you to make later, more critical drops as well as being much more stable during tuberides.

quad_barrelPat Maus puts his quad to the ultimate test.

Also, we can't forget about the youth of today. Most of them just ask: "Does it do good airs?" Across the board, surfers will all agree that the quad can punt some good-ass airs! One of the reasons being is the fin placement on the trailer fins. If you look at a regular tri-fin setup, you'll notice that rake from the trailer of the tri-fin more often than not ends up right at the end of the tail. That means when doing an air the last thing to leave the lip is that trailer fin, giving it a feeling of tracking off, if you don't nail it just right. Now, with the quad, that last thing to leave the water is tail, not a fin, so you can kind of imagine in your head: "Sliding of the tail brings nose underneath me and oh-my-god, I just pulled the best air ever!"

Why do most pros stick to tri fins? I think it has a lot to do with them just being so familiar with tri fins. I'm sure some guys on tour figure, "If it ain't broke, don't fix it." It could also be that most pro surfers are under a tremendous amount of pressure from their sponsors to win or get good results, no matter what. That could tend to mess with a man's willingness to wanna try new equipment. However, I'm sure the most loyal professional tri-fin surfer has at least one quad in mix.

Is there anything missing from the quad ride? No, I think they are the most well-rounded surfboard out now. One thing I would really like to let people know is that the brand of quad has just as much to do with your perception of a quad. What I mean is, just because you have a shorter, wider surfboard with four fins on the bottom doesn't always mean you will get the performance that so many people talk about. My only advice to anyone looking to progress their surfing ability by riding a quad would be to do a little homework and go with the guy who has the most experience.


Jeff Clark on quads:

Started focusing on quads for big waves around 1990. With guns, it's an easier formula -- you're drawing longer, swoopier lines. Tri-fins stay centered; they want to go straight. Tri-fins pivot. Quads have inherent speed and hold, but there's an information gap -- a void -- going from one rail to the other. (Lots of vee on quad gives a centering feeling.)

The goal was to build a board with the best qualities of both designs; to make a quad feel more like a tri-fin than a twin-fin. At first, the fins were too close to the rail. I moved them closer together - 1 3/4 to 2 inches off rail. I experimented with wider tails at first, around 11.5" on guns in the 9'6" range. They were too wide; so I brought them back to 9.5" to 10.5".

First instinct on late drops is to set a rail; tri-fins want to straighten out. It's that centering thing -- trying to set a rail and battling with the back fin. Quads want to find one rail. Unlike a three-fin board, there is no conflict between front and rear fins. They are all pointed towards the nose on either side of the board.

A tri-fin with flat-sided fins will cavitate, and with the back fin not connected, you find yourself sliding down the face -- you have to go straight or flatten out to reconnect.

Big wave quads: nine inches of base (two fins) in the face on your inside rail; 80/20 foils hold better. You never have to adjust your line back towards flat or perpendicular to the wave's energy to reconnect.


Pat Rawson's take on quads:

When the energy is running down the line, more surfers are receptive to the qualities of a quad. When the energy is coming in towards the shore, the preference is generally three fins.


Personally, after working with Pat Maus a few years back, I made myself one and have been riding them almost exclusively for the last five years. The only time I might switch back to a tri would be in a short, hollow, backhand wave. After riding them for a few years, I made a convertible for laughs. At one of my favorite testing grounds, a fairly long hollow left (frontside for me), I took it out first as a tri. I thought to myself, yeah... I remember this feeling. Solid bottom turn, up the face, snap off the top -- feels pretty good. Surfed for a couple of hours. Took a break. Went back out with it switched to a quad; pretty much the same conditions. The board was so much faster and quicker on was night and day. I haven't look back since.

Like a Wikipedia entry, this thing will grow and change. Any constructive input is welcome. Thank you for your help on this:

Bruce McKee
Nick Carroll
Pat Maus
Larry Bertlemann
Jeff Clark
Glen Winton
Simon Anderson
Pat Rawson
Greg Mungall


Thanks to our friends over at

Talking Design with Rusty: Quadrophenia – Part I

Four fins are faster than tri fins.
Four Fins are looser than tri fins.
Four fins ride the barrel higher and tighter than a tri fin.
They drop in easier.
They come out of the gate quicker.
Accelerate on cutbacks.
Do better airs.
Can be ridden shorter.
Draw new and different lines.


Josh Kerr is one of the half-dozen or so of the ASP World Tour who regularly experiment with quads.

So why isn't every surfer on the planet riding one?

It's all Hype?
Different strokes?
The pros don't so I won't?

Maybe shapers don't have it right...yet?

Perhaps if there were a ubiquitous effort, a Manhattan Quad Project, the design would evolve at a faster rate and all would enjoy the benefits.

Sorry, somebody has to win a major friggin contest on one first. (Biggest win? CJ won the Body Glove Surfbout on a quad in '07.)

So at this point, who seems to like them and who doesn't? And why?

Typical first impression of a quad is this: fast and loose, but not confident without something directly under the back foot. It takes a few sessions to trust the setup -- and run with the positive attributes.

The lack of an auto-centering sensation seems to be a common complaint from most detractors. Without a center fin, a lot of surfers miss the instant feedback from the back foot and the ability to do quick adjustments. With quads there is an information gap in rail change that varies widely depending on fin (rear especially) position.

Backhand performance is also a concern of 3-fin loyalists. Going heelside, the rider delivers more power through the rear foot and specifically the heel. Visualize foot angle and where the energy is going...for most surfers pretty much in line with the rear fin, three inches and change from the back end.

Early days of the 3-fin, I'd put rear fins way back on some rider's tail blocks. It was necessary to do this to keep more powerful, rear-foot surfers from blowing their tails out on acute direction changes. Occy's were set at 2 3/4" and some of Tom Carroll's trailers were as far back as 2" from the end of the board. As rockers and outlines evolved, the rears crept up to 3 1/4" to 3 1/2" on an average shortboard.

If a rear fin on a tri is moved up an inch or two from the placement most people are used to, the board loses drive, hold, and moves the pivot point further forward. A surfer would have to completely readjust his rear foot placement. Same holds true with a quad.

Which leads to probably one of, if not the single most important detail in designing a 4-fin surfboard: fin positioning. Not weird-ass tails. Not crazy bottom contours. Fins. How big they are, outlines, and foils. Where they are, their relative positioning with respect to each other, cant and nose vector.


Jamie Sterling is a fan of quads in the barrel at Teahupoo 'cause they go fast and hold at speed. Photo: Tyler Cuddy

Early on I took a fairly simplistic approach to it.

Early quads were an attempt to add drive and control to twins. In 1980/81, Twins were de rigueur. Since 1982/83, tri-fins were most surfers' experiential basis. In my mind, I'm starting with a tri-fin. So I took the rear fin on a tri, and was theoretically splitting it in half. The more the rider wants the feel of a tri, the further back and closer together I'd keep the fins. If a rider was after more of a twin-fin feel, I'd move the rears towards the rail and the front fins.

My common middle ground: for argument's sake, a 6'2" tri-fin has fronts at 11" and rears at 3 1/4". A lot of designers go half the distance on a quad, so that would put the rears at 5 1/2" and the same distance from the rail, about 1 1/8". In my humble opinion, I feel this is a little on the neutral side. I split the difference on distance from the tail (tri vs. quad: 2 1/4"), which would be 3 1/4" plus 1 1/8"...or 4 3/8". Easier math: 7' board. Fins at 12" and 4" on a tri. Half the distance is 6". Split the difference, 5" for a quad. On average, I try to keep my rears about 2" in from the rail. That's a generalization. It becomes a more complicated depending on tail width and board length.

Fin size: Fronts are similar to tri-fins, perhaps slightly smaller. Rears: profiles similar to fronts reduced approximately 10% in overall area. You can adjust drive by swapping out rears with different aspect ratios. More upright fins for tighter arcs. More rake to add length and draw to turns.

Foils: Your preference on fronts...your favorite tri fin fronts are a good starting point. If you are a fan of cambered fins -- stay with them. If you prefer flat-sided fronts, you will probably like them in the trailers as well. Smaller, weaker surf; flats are probably the go as they react a little quicker and provide instant feedback. Bigger, more powerful surf -- most prefer cambered or dual (full) foil trailers. Less prone to cavitate and let go. Some prefer full-foil trailers in everyday surf, citing more "feel"...smoother, cleaner, etc. Not as fast.

Cant on rears: Typically, I halve the angle of the fronts. It can vary according to intended use. Smaller softer surf; a little more cant will add some lift and looseness. Conversely, less tilt will increase speed, hold, and drive.

Nose vector (line towards nose): I typically point all four fins to approximately the same place, which depends on board length and type of surf the board is intended for.

Another shaper's insight into quads and fin positioning: Bruce McKee has done nearly 30 years of homework for all of us and he's quite happy to share it here.


Why not chuck a quad in the back with the rest of your quiver? Photo: Tyler Cuddy

So back to...why aren't more surfers embracing this design?

I suspect that there were probably a lot of takers that might have had a go early on before a lot of work had been done. They may have had a less-than-satisfactory experience and shared it with others that may have at one point been interested.

Some of it may be due to negative stigma. The print media. In an incredibly myopic and disappointing "Surfboard Issue" last year the polyurethane/polyester tri-fin was declared the winner and still champ in a fizzling technology push.

Thankfully, we have the Internet.

Search and you will find. There are quite a few board builders offering quads. Even Simon Anderson himself rides and enjoys quads and has several models in his product line.

My suggestion is that if you are interested, search out a builder who embraces the design and has a solid history with the setup. It's not as easy as just sticking four fins on a board.

More often than not when I let someone demo a quad they are pleasantly surprised.


Check back later this month for "Part Two: A History of Quads," with words from Simon Anderson, Jeff Clark and more.



Last month's blog on tails, we received a question in response to the Simon Anderson story:

So Rusty - did you build a thruster later that same night? --Munga

Rusty answers:

I tripped on the experience for a couple of days, wrestling with the thought, was it the board or the surfer? My mind said it was 90% Simon.

After a few days, wtf, I stuck a trailing fin on my favorite twin. My first surf on the jury-rigged tri-fin was in decent surf but it was not nearly as good as Blacks on that day I watched Simon. First impression: board was noticeably slower but had a tentative short burst of speed out of turns on the better waves. It felt like the parking brake was on but when I drove off my back foot hard enough the board would come back up to the speed it had as a twin...just briefly, and as soon as I let off, it would slow down again.

I shelved it.

The next board I made myself after the twin to tri-conversion was a 4 fin round-tail. It was a super fun board. It had the speed of a twin but with more drive and a bigger sweet spot. I vividly remember it doing swooping cutbacks at full speed, almost effortlessly. I rode it for a few months.

Thanks to .

Talking Design with Rusty: The History and Functionality of Tails


I call the back third of a board the business end. Rocker, fins, foil, and outline curve all work in harmony, ideally, to provide the rider with a desired feel.

Questions about tail shape seem to get asked most frequently. Understandably so, because in the last decade or so there has been a proliferation of "new" tail shapes. Tails are easy to separate and the visual differences are easy to identify.

To understand how tail shapes have evolved, I'll offer a little history. I don't profess to be a historian, but here is a little overview. At some point in time, thousands of years ago fishermen started standing up on their small hulls on the way in through the surf. Canoe? Kayak? Reed hull?

It's almost like speculating if there is life on other planets but it's safe to say that there were quite a few early fishing communities around the globe that were comfortable going out through surf and coming back in. Whimsical thought, children would play in the surf with small flat pieces of wood and some would stand on them.

A few hundred years ago, prone craft got supersized so adults could participate in the fun. Someone flew at a higher altitude and realized that the outline of a boat made sense but they didn't need all the volume. Once propelled by a wave's energy, volume becomes less relevant and early board shapers became intrigued with outline shape.

Eventually, the penny dropped and the importance of the planning aspect of a craft built specifically for wave riding clicked in and surface area became more important than volume -- a craft in motion.

How does a slab of indigenous wood (or flotsam from shipwreck for that matter) become a wave riding craft? If you look at the most primitive of shapes from early wave riding cultures you'll see that the shaper of the period has taken a rectangular plank and rounded the nose off a bit. As boards evolved, the rectangles became trapezoids of sorts: rounded nose, wide point was quite far forward. The board gradually tapered, on some designs almost imperceptible, to the tail section. Tails were wide and square with slightly rounded corners.

A designer's inner dialogue boils down to striking a balance between planning surface (area, lift) and control. Sometime in the early 1930s designers began cutting away area between the corners. Possibly to make it easier for the prone paddler to kick while still maintaining rail length for lift and control. These inverted arc tails may have been the precursor to a "fish" tail.

Tom Blake is credited with putting the first fin on a surfboard in 1935 to facilitate steering and is said to have built a two fin board in 1943. Simmons, quite possibly unaware of Blake's two fin board, built some two fin boards in 1948. Simmons built bigger, wide back, rounded square twins and a few shorter ones in the 50's. Tom Blake reshaped a Simmons square tail into a split tail, "The Makaha Wedge" around 1954.

266An early Tom Blake design. Photo: Tom Blake\Surfing Heritage Foundation

This was most likely the inspiration for the Mirandons to build a single fin with a fairly wide split in 1967 called the Super Board and followed it with the Twin Pin: a double pin tail twin fin, in 1968. Arguably, the Twin Pin was the inspiration for Steve Lis to incorporate the fish tail and two fins into his very short kneeboards. Richard Kenvin has been working on a project, Hydrodynamica, that weaves all this rich history together.

Traditional fish have roughly a 10 to 12 inch split. Area and volume is removed between the corners. Maximizing rail length, enhances drive, adds traction, and releases quick. The further apart the corners, the less continuity there is in rail transition. The notion was to have a long, straight rail on a very short, wide board. Typically, the wider the gap, the deeper the cut. A round pin template can be used for the inside part of the curve so a deep cut doesn't lose too much area and the inverted pintails don't get too pointy. The deeper cut also allows the individual tail, the one in the water on a turn, to flex more readily.

Rewind just a bit: in the 1950s, with materials changing, boards becoming lighter, fins accepted and evolving, outline shapes and tails shapes were experimented with as well.

In 1954, Dale Velzy, bored with the same old outlines, used his nose template for the tail. This pulled the wide point well behind center and, while it may not have been the first round tail, "The Pig" popularized hips pulled back, and very curvy tails; rounded squash, round tails, and round pins. More curve equals tighter arcs and surfers found themselves accelerating out of turns. The era of angled takeoffs and straight line trimming was transitioning into the early days of modern, maneuver-based, performance surfing.

Velzy's "Bump" (1956/1957) featured an exaggerated hip which was arguably the precursor to the wing, or sting. In 1960, Velzy had a go with some ski inspired outlines, inverted parabolic midsections, and a version with an inverted midsection, with the wide point 2/3rds back, pulling into an almost nippled pin tail which he dubbed "The Stinger". Then in 1963, Velzy designed the Banjo/422 that featured possibly the first modern version of a step down type wing about 2/3rds back.

So this gets us into a period where experimentation with outline curves, hips, and tails is accelerating. With the short board revolution, single fins (and straighter tail rockers) arguably impacted tail widths and shapes. With shorter rail-lines, designers were searching for ways to build speed and drive back into the boards and still keep them from spinning out.

Tail widths and shapes in the late 1960s and up until the inception of the modern three fin were somewhat constrained by the limitations of a single fin.

With the Mirandons and Lis resurrecting interest in two fin boards, tail widths expanded. Also, in 1970 Hobie and Bing both marketed wide square tail twin fins. These incorporated totally different approach with fins.

In 1971, Brewer, Reno, McTavish and others start experimenting with three fins. These early versions were primarily two plus one setups: a single fin with small side-bites glassed on the rails, roughly about mid-base to the main fin. This allowed for a shorter main fin and wider tail blocks and experimentation with wider, "closed tail" designs, ie. squash tails and diamond tails. That same year Gary Goodrum won the US Surfing Championship at Huntington Beach riding a three fin.

The mid-1970s saw a lot of split tail design incorporated for small wave designs. While pin tails, and diamonds were left for larger surf. The fish, swallow, dove tail, allowed for wider tails on singles fin boards. Width, with the area removed between the corners, provided drive and hold with a quick release on tails. A more modern, split tail twin fin moved into dominance in the late-1970s.

In 1981, the modern three fin changed everything. Hot dog boards with wide squash tails took over. Squash tails maintain dominance for most small/medium wave designs. By mid-1980s more roundtail three fin boards were working their way into the mix.

Today, what I find fascinating is, most of the short, "performance" boards that I build, and other designers boards that I look at, have remarkably consistent width numbers the last 18" of the board. Width at 6", 12" and 18" up from the tail are very similar between shapers and designs for boards that are ridden in everyday conditions.

A few years ago someone came to me with a concept board that would allow the owner to change out the tail of the board. The width at approximately 18" up from the tail is around 16 ½" so the designer had interchangeable tail sections that joined the board at the 16 ½" width mark, wherever it fell, and allowed the owner to put in slightly shorter or longer and different tail shapes. He had some working prototypes and the thinking was sound. Depending on conditions or mood of the rider, the board could be modified to perform accordingly.

All things being equal here's kind of a basic breakdown on tail differences:


Square: Probably the grandfather of all tails, maximizes rail length and area in the last foot or so of the board. It adds stability, drive, more angular turns, quicker release, and less continuity in rail-to-rail transitions. They are used by some shapers as a small wave design and were used by some shapers in early big wave designs -- gun pioneers like Pat Curren used small square tails on guns.


Fish Tail, Swallow Tail, Dove Tail, Split Tail: A square tail with area removed between the corners, fish is a catchall name. Split tail is a name that doesn't initiate semantics debates. Fish used to be a wide (10" to 12") split with a fairly deep cut about half the width number. Quite often, shapers will use a round pin template to create the inner curve. Swallow was a used on more of a standard hotdog type board with a 5" to 7" split. The depth was an inch, give or take and the inside cut had curve. A Dove tail was similar width and a little shallower depth with a straight inner line. Width, depth of cut, and area (fullness of curve) of the inverted pins can be used to achieve different riding qualities.

An interesting sidebar on splits with deeper cuts is they promote flex. Plenty of shapers over the last few decades have experimented with thinning out the pins to the point where they are virtually just fiberglass.

Baby swallows or baby fish tail refers to a narrower tail on a gun with a split that maybe as small as 3" or 4".


Squash or Rounded Square: Here's where we start getting into semantics and hair splitting on the names. Maybe a squash tail is a round pin someone dropped and a rounded square is a square that had its corners sanded off. Basically, they are both shaped by rounding off the corners of a squaretail. In addition to the usual checkpoints, I track numbers 1" up from the tail and 6" up from the end of the board. An average squash tail is about 10 ½ wide 6" up. The 1" number reflects how much curve there is because it's difficult to measure the end of the board unless it has distinct corners, like a fish tail or a square. An average squash is somewhere in the 5 ½" to 6 ½" wide at 1" up.

This is probably the most common small/medium wave tail shape. It offers a nice blend of area and curve. It became the go-to tail shape when three fins took over the world in the early 1980s. There were wide squash tails built early in the shortboard era. The problem with wide tails on single fins was that the wider the tail (block) the deeper the fin needed to be. The deeper the fin, the more the frontal drag. With three fins, it really enabled designers to go wider and shorter, moving area aft because of the hold and drive three fins brought to the game. The tail shape provides lift, support, and drive.
The balance of release and smoothness or continuity depends on how rounded the corners are.


Diamond Tails: A blend of round pin and squash with the corners moved forward a bit maintaining area, shortening the rail, finishing with a subtle point, and a very clean exit for a board with some tail vee. Diamonds were used quite a bit in the early 1970s on a wide range of boards all the way up the ladder. A nice blend of aesthetically pleasing yet, still very functional.


Bat Tails: Take a squash or a diamond and invert the last inch of the tail. I did 'em in the early 1980s. They are all the rage for quads now. The area removed and little corners add some bite and help give the boards without a rear fin in the middle a little extra drive.


Round Tails: Uber-smooth turns. Make a clay model of a hollow wave, use a wire to slice it along the speed line in the barrel, and the cross section will probably look something like this. Or Google conic sections. This tail is a clean, natural curve that fits the pocket. It's a great tail for a performance shortboard, good in head-high to double-overhead waves. Also, a good option for next one-up type shapes.


Thumb Tails: Look like the tip of your thumb -- a blunted round tail with little less curve between front and back fins. Area in last few inches can vary compared to a roundtail; a little less than a squash tail. It's an excellent all around tail shape with the smooth transitional qualities of a round tail and a little bit of release that you might feel in a squash. Combined with a slight hip or subtle bump, it makes an excellent tail for everyday conditions and into the good stuff. Probably the second most popular tail, behind the squash, for performance shortboards.


Round Pins: Are typically used on longer boards for bigger waves. As the board gets longer, the curves get stretched out, it becomes a bit of a juggling act for the designer to maintain a balance of curve and area.

A tail that is too narrow sits too deep in the water, compromising the board by creating unnecessary drag. A tail too wide creates the opposite problem.

Once again, remember that rocker, fins and foil all come into play as well.

With 1970s style single fins, the wide points up, long rail lines in the back, and pinny pintails (low area) were necessary to keep the tail in the water in bigger surf. Tri-fins allowed designers to go a little wider and use more rocker because of the hold and drive created by the three fin setup.

With quads, it opens more doors.


Arc, Half Moon: I seem to do a lot of tow boards with this tail as well as some guns. Back to maximizing rail length, maintaining some width, and removing some area behind the fins.


Toad Tail: This is when the line starts to blur on "is it a wing or a tail?"

I worked with Will Jobson on Twinzers in the early 1990s. The Twinzer was a not really a four fin but a twin fin with little fins in front of the main fins that help feed the water onto the main fins to help them work more efficiently. Martin Potter charged to his world title riding a lot of these (Will's and Glenn Minami) designs. Will had a tail that looked similar to this but with the corners pushed even closer to the end of the board. He also had concaves running out through the corners. All these design elements he combined to make his visionary fin setup fly. The wings, or corners, step down the width, create release and hold. They're good for four fin boards. I've made three fin boards with this tail that have had great reviews.


Asymmetrical: Who says tails have to be symmetrical? My first board was an Ekstrom asymmetrical. I've built a few over the years and had a couple good riders swear by them. I made myself one last year and had a blast on it. Swallow wing on the frontside, roundtail on the backhand. Drive and release toe side, shorter, power arcs heelside.

In the mid-1970s, I shaped myself two swallow tails, identical in every way (as best I could do handshaping). When they were both finished, I sanded some of the curve out of the tail between the corner and the 12" mark. Some area removed, but more noticeable, a subtle hip or break in the curve. Any difference in the ride? Night and day. The one with the break in the curve won, hands down.

There were days back then when I was surfing solid winter Blacks on guns with the cleanest, smoothest curves I could make, and sometimes found myself wondering if an outline could be too clean. Beautiful, but vanilla.

Some things to remember:

Corners and aberrations break the line.

Smooth curves beget smooth turns.

Area affects lift and resistance.

Once again, it's the whole package; rocker, fins, foil, and entire outline curve that dictate the overall feel of the board. Tails are embellishments.

No right or wrong. Whatever flavor you are after, there's more choices than ever.

Happy Surfing.

Photos: Brody

Talking Design with Rusty: Volume and Curves on a Fish


"I'm 195 lbs and 5'10" and in good shape with most of my weight on top. I ride a 6'6" to 6'10" for my normal shortboard and got a 5'10" fish this year. I love the ability to get into waves, the speed and maneuverability in under head-high surf, but have problems with the outside nose rail digging at times. I also have problems with steep takeoffs because of the lack of nose rocker. What aspects of the fish should I keep and what should I change?"

Rusty, who's been shaping since before the original fish was invented, fillets the question:

Ironically, the traditional/old school fish was designed for and excelled in fast hollow waves like Old Break, Big Rock, and Blacks, but it was primarily ridden as a kneeboard and ridden much shorter than your board at 4'8" to 5'2". In fact, 5'6" was considered big. Eventually more and more people actually started standing up on the bigger ones and discovered that they were fast and maneuverable (sort of) in small, mushy, running waves. If you are interested in more background, hit up Eric Huffman at:

Rocker, or lack of, can be the culprit when a nose pokes on takeoff: the board isn't fitting the curve of the wave. Either the board needs to be shorter or have more curve. On your next fish, try a little more rocker in the nose and possibly the tail. A little more curve in the back half is just as important -- if the tail curve isn't fitting in the steepest part of the wave, it will lift the back end and drive the nose in.

It is important to have some balance in the curve. By that I mean the rail arc needs to flow from one end to the other. Having excessive curve at either end won't correct the whole package and abrupt changes in curve will cause drag.

Your outside rail digging is partly related to rocker and is also probably a result of the nose being too wide for certain conditions. Once again, the back half of the board may be coming into play. If the tail is very wide and the outline curve is straight (factor in low rocker), the back end of the board won't fit and/or release in a controllable manner.

Again, I am assuming your board is a traditional/old school fish. My numbers on this type of board are something like this: 5'10", 2.3" thick, width: 15.5" (nose), 20.5" (center), 16.5" (tail) and 12+" corner-to-corner on the pins. Rocker: 4.25" (nose), 1.3" (12" down from nose), 0.52" (12" up from tail) and 1.4" (tail).

My suggestion would be to pull in the nose and tail about an inch or so, leaving the middle width about the same. Pull the corners of the tail in at least an inch, maybe more. As the fish evolved, it sprouted wings. This helped to step down the width on the back end of the board and reduce the pin-to-pin distance to something on the order of 10".

Rocker: A little goes a long way. The front end could come up to approx 4.5". The back end on the older fish was low -- something on the order of two inches in the tail. Once again, an even curve would probably be a lot more user friendly in a broader range of conditions.

Thickness: The old fishes were flat, but relatively thin compared to other boards of the day. Adding thickness to a flat-rockered board becomes a little problematic, in that the deck line starts to develop a hump, or an "S-deck", and transitioning out to a clean rail line becomes more challenging. To compensate for some of the volume you have given up by pulling in the template, you can add a little thickness to the center. With a little more bottom curve, you can probably add back in some thickness in the midsection.

Fins: A lot of the old school boards have the glassed on wood keel fins. These were designed to build more drive into very short boards. As you go longer, you have more rail and can probably get away with a shorter-based fin. If you don't have removable fins, try a fin system so you can experiment with different feels for different conditions.

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Talking Design with Rusty: The Secret Behind Displacement and Big-Guy Shortboards

Hayes Domler Asks:
"I've been surfing for over 30 years and have gone from shortboards to longboards and back to shorter boards. I'm 6'0, 200lbs. I'd love to get a big thruster that would work in quality surf and would probably work in average surf, too. Can you help me?"

Rusty, being a big guy himself, tackles the question head on:

What's considered big for the non-surfing man? Let's say 200 pounds and up. So what's average for a surfer? Well, for argument's sake, let's say 150 to 170 pounds. But 180 is starting to tip the scale. Any pro surfer 190lbs is considered big -- Jordy Smith, Jay Davies, Pancho Sullivan, Sunny Garcia, Luke Egan -- while 200lbs is considered really big. Simon Anderson, a.k.a. The Gentle Giant, surfed in competitions at 6'3" and 210 pounds. There are a lot of very fit surfers who are, simply put, bigger than average.

simon1 Thruster-inventor and former World #3 Simon Anderson was a big dude, which never slowed him down, especially at Sunset. Photo: Dan Merkel/A-Frame

At 200 pounds, a young, fit guy surfing in good waves can probably make 6'2"x18.5"x2.3" work for him. Yet, 6'3"x18.75"x2.4" is probably a little more practical.

Here are some other examples. A retired pro surfer in his mid 30s, standing at 6'3" and 230 pounds would probably ride a 6'5"x19.5"x 2.5". But when he was in competitive form, he probably would've weighed 200 pounds and rode a 6'3"x18.65"x 2.3".

Or take a 6'5", 230-pound, professional athlete in his early 20s who is an experienced surfer. His board would be 6'6" 19.75 by 2.6. Meanwhile, a 6'7" 230-pound retired NBA player in his early 40s would need a 6'10" 21 by 2.8-inch board as an experienced surfer.

Then factor in age, fitness level and venue, and the numbers change.

A lot of guys fall into the "vanity versus reality" funk -- if you're working too hard and not enjoying yourself on the same board or dimensions that served you well a few years ago, go a little bigger. If fun becomes work, you're only hindering yourself. Go a little longer, wider, thicker and you will increase your wave count and stoke. You'll probably surf more often and the fun and fitness will be restored.

People often ask whether there's a formula for volume. Here's an astute observation from one of the readers of our previous blog:

Tom G. 05/19/2009 04:25 PM
"Could you help bring back the volume measurements of surfboards? Maybe even weigh the boards too...(~5-10% difference). It could improve consumer confidence (for the average guy) in avoiding the worst purchase for most surfers -- a sinker that floats you at your neck! For example, some people think you should surf something no less than 35% of your volume. So if I weigh 77 kilos (170 lbs) I should surf a board that displaces 27 kilos of water (27 liters). Would this help the movement?"

Jamie O'Brien weighs in at about 180 pounds and typically his go-to board is 6'2"x18.5"x2.27" inches and displaces a volume of approximately 27.5 liters (or about 77 beers, as one CAD program conveniently calculates.) I've made him shorter, wider boards and I do use the volume tool on the software as a cross check.

Jamie O'Brien putting his edge to the test at Teahupoo. Photo: Sean Collins

Nate Yeomans weighs about 170 pounds, though he rides similar dimensions with slightly leaner rails. So I would say you are on the right track, Tom.

Ability level and venue also must be taken into consideration, and in no way is it meant to be disrespectful, but these are realistic factors when finding the right board for you.

Alex from Sweden 05/20/2009 02:43 AM
"I'm 6'3" and about 220 pounds with wintersuit and all. Even worse is that I surf mostly in the Baltic Sea that is cold and has much less salt, meaning less buoyancy. I don't fancy longboards or funshapes because I want a stable board that can carve and snap but still handle less buoyant water. My question -- what kind of board, and especially size, do you think would suit me?"

Venue is always a factor. Again, another spot-on comment, this one about salinity and buoyancy. The best way to add volume is to add width. This will increase stability but the trade-off is a reduction in reaction time. Wide boards aren't necessarily any slower than narrower boards in terms of how fast they are capable of traveling down the line but width directly affects the quickness of a board with regards to rail-to-rail transition.

Simply put, for bigger surfers: width is your friend. You don't have the same quick twitch muscle speed as your smaller brethren. You have more power. Design you board accordingly. Head high is all relative. Adding thickness will add buoyancy -- the trade off is a decrease in flex and sensitivity. And while adding length may allow you to catch the wave a little earlier, the trade off is possibly compromising how the board fits in the curve of the wave and increased arc length on turns.

A big part of a shaper's job is finding a good balance between all these variables.

Your board should somewhat reflect your build. Shorter, stockier surfers should probably consider adding the extra volume they need with a little extra thickness. Taller, leaner surfers may be better served by going a little longer, and wider. The extra width is important to maintain outline curve. For every two inches of change in length (+/-) approximately an eighth of an inch (+/-) will keep the curve somewhat similar.

Foot size also comes into play. Sasquatch doesn't want his toes hanging over the rails and he can probably handle more width because of the leverage he can deliver with his big feet.

Pancho Sullivan - big guy board, big-guy carve. Photo: Jeremiah Klein

It's difficult to generalize and that's why I think it's so important for anyone who wants to maximize his or her surfing to work with an experienced shaper on customized equipment. Once again, this isn't so much about old-guy or fat-guy boards, but really trying to throw out some practical solutions for the surfer who's bigger than average and frustrated with trying to find a happy middle ground between challenge and reward.Average sized surfers are generally happy with fins that have a base and height of around 4.5 inches and a flex pattern that incorporates a somewhat softer tip. Bigger surfers should be looking at fins in the 4.65 to 4.75 range, base and height. Also, avoid softer fins. Plastics are a no-no. Some RTM fins are good. Carbon tends to be too rigid. Nothing beats a well-foiled, all-fiberglass fin. In smaller surf you can sub in a set of five-inch (give or take 1/8") front fins for more lift and drive and drop in a smaller rear fin to free up your tail.

Quads? I'm a big advocate, especially for larger surfers in everyday conditions.

As far as materials and construction go, bigger guys have more to gain from EPS/Epoxy. With lighter, quicker surfers, I usually adjust the volume down to compensate for the increased buoyancy. While bigger or more "experienced" (a.k.a. older) surfers usually choose to enjoy the additional paddle power.

There are so many variables to factor in, but here's a stab at a super basic spreadsheet:

#1: A board with typical shortboard proportions. (From a distance, under a bigger surfer's arm or on a wave, it would be difficult to tell how long the board really is.)

A 3-inch difference between nose and tail
Nose 11 to 12 inches
Tail 14 to 15 inches
Wide-point an inch or two back
More of a "back foot" design

Assuming average ability, average surf condition and that the surfer is reasonably fit, surfing three-plus times a week.

20 to 30 years old:
200lbs 6'6" 19.5 by 2.5
225lbs 6'9" 20.0 by 2.65
250lbs 7'0" 20.5 by 2.85

30 to 40:
200lbs 6'9" 20.25 by 2.7
225lbs 7'0" 20.75 by 2.85
250lbs 7'3" 21.25 by 3.0

40 to 50:
200lbs 7'0" 20.5 by 2.75
225lbs 7'3" 21.0 by 2.9
250lbs 7'6" 21.5 by 3.0+

50 to 60:
200lbs 7'3" 21.25 by 2.9
225lbs 7'6" 21.75 by 3.0
250lbs 7'9" 22.0 by 3.15+

#2: A little more balanced, user-friendly shape

A 1.5-inch difference between nose and tail
Nose 13 to 14 inches
Tail 14.5 to 15.5 inches
Wide point moves closer to center

Assuming average ability, average surf and a reasonably fit guy, surfing one to two times a week.

20 to 30 years old:
200lbs 6'6" 20.5 by 2.65
225lbs 6'9" 21.0 by 2.8
250lbs 7'0" 21.5 by 3.0

30 to 40:
200lbs 6'9" 21.25 by 2.75
225lbs 7'0" 21.75 by 3.0
250lbs 7'3" 22.25 by 3.1

40 to 50:
200lbs 7'0" 21.5 by 2.85
225lbs 7'3" 22.0 by 3.0
250lbs 7'6" 22.5 by 3.15+

50 to 60:
200lbs 7'3" 22.25 by 3.0
225lbs 7'6" 22.75 by 3.125
250lbs 7'9" 23.0 by 3.25+

There are many other options in design that will allow you to go shorter if you choose. Boards that are wider in the nose and tail with more relaxed rockers work for certain types of waves. Or go longer for that matter. It's all about the waves you surf and the lines you want to draw.

Form follows fun.

Check out Rusty's Blog on and Keep Those Questions Coming!