Does anyone have advice on the basics of rail design for shortboards?
how far the sharp edge at the back should come up the rail before softening?
What effect do too sharp rails have on performance?
What profile dimensions are recommended for all around rail to rail performance?
Etc.
thanks for any advice!
Something I learned from riding Greg Griffin’s short boards. I put a tucked under edge from about 15-20 inches back from the nose tip to the tail. There’s a well defined hard edge. Greg’s boards have a lot of crown on the deck and that gives the board a nice thin rail, but I’ve made a couple of boards with a flatter deck with a fuller rail and they work pretty good.
This would be for boards for Hawaii. I don’t know if boards fro other places need a softer rail. I like the way the tucked under rail feels. I think I get more projection out of my turns, and the boards are faster than the boards I have without that edge.
Just mt 2 cents.
Read the archives, watch a shaping dvd and copy a board you like. These are pretty basic design questions and if it’s your first board it’s gona look like you had an epileptic fit on acid whilst wielding a planer so just have a crack at it.
Also, see M_Woo’s comments and others (same thread) on the relationship between stance and rail
Whether you agree with M_Woo or not on the particulars, it is a package deal, ultimately driven by surf conditions and the surfer’s objectives. A complete knowledge of the breath of relationships is beyond me, as conditions where I surf [Northeastern US] tend to top out at about around mid-range, with the rare big day, but obviously there is plenty of experience on this site for virtually any given set of conditions. Yet there are some guiding principles, like the relationship with stance which are going to be true regardless.
kc
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Does anyone have advice on the basics of rail design for shortboards?
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Most have down rails. Down rails have more bite. Google surfboard rails and youll get some hits on basics.
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how far the sharp edge at the back should come up the rail before softening?
What effect do too sharp rails have on performance?
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Industry average is a shaka sign ahead from the bottom leading edge of the rail fins. Sharp corners help to release attached water flow at the rail, which helps to facilitate acceleration, speed and lift. Softer rounder rails allow more water attachment, maintaining more drag and are generally slower and more user-friendly.
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What profile dimensions are recommended for all around rail to rail performance?
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Sorry, I dont understand the question. Go to your local surfshop and look at as many boards that fit your criteria to get a general sense. Use the web of skin between your thumb and index finger as a "guage". PingPong ball to Golf ball radius give or take is pretty close. Have fun.
I agree with you, also preferring tucked under, round when hitting the water, sharp when releasing. I like them transforming from round in the nose to sharp in the tail and thin so they cut the water well, not bump as fuller ones. Not in Hawai, but in Dutch slop and something more powerfull too.
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watch a shaping dvd and copy a board you like. [/quote]
Have you got an example? I have watched some DVDs, but the rail chapters arent very illuminating!
May be this will help you
http://www.greenlightsurfsupply.com/knifey_railbands.pdf
Comment on the topic from Maurice Cole on Surfline
Why don't boards have hard rails all around?
Shaper Maurice Cole addresses the issue of hard rails
QUESTION
I was wondering why a typical thruster -- or most boards for that matter -- tend to have rails that are softer towards the front, and harder in the rear. Why not have hard rails all around?
I was thinking that maybe the softer rails up front make it easier to pump, but I don't know. Thanks.
Asked by Bobby
ANSWER (Posted 02/25/03)
Maurice Cole, replies:
This innocent seeming question is hitting modern high performance design right on the nail. The logic of hard rails-versus-soft deserves to be challenged. Mark Richards once said, "Hard rails don't catch, bad rocker lines do." This would have been 20 years ago. I think we're only beginning to get a grip on what he said today.
Why do boards have softer front edges? It's simple. In traditional surfing style, the front half of the board is essentially irrelevant to the turn. Most of the time, you're lifting the nose out, and only using the last two feet of tail rail -- the hard bit -- to turn.
Rails have been left soft up front because many designers have believed that hard edges up front would "catch" -- ie., interfere and block water in turns. I think this is a fallacy on the modern high-performance surfboard. The softer front edge is designed to be forgiving. In fact, it's too forgiving. The softer the edge, the more the water wraps around and sucks onto it, the less control you have. It's like sloppy suspension on a car.
Here's an example: you've probably seen the footage and photos of the Jaws sessions late last year. What we (Ross Clarke-Jones rides MCs) found was amazing. Ross was riding 6'6"s and they actually felt too long! In 30-foot waves! Those boards had hard rails from nose to tail and yet they didn't catch -- in fact, they were incredibly lively. They felt too long because suddenly Ross was able to use the whole rail to turn off, not just the last two or three feet. We've cut lengths down to 5'10" and 6'3" and we'll probably cut more after the next swell.
Tow-ins have taught me over and over again that we don't know what we thought we knew. I believe we've gotta be able to translate that back to everyday surfboards. I went in on my high performance boards recently and started putting hard rails in way up, from nose to tail. All I found were improvements. The boards paddled better; they took hold of water and got it under the board quicker; reaction times improved. You could use all the board, all the time.
Surfboard rockers have improved tremendously since MR called it on 'em way back when. Maybe it's time we kissed the soft front rail goodbye.
On Wegener's website he also goes in to this subject. One of his favorite boards (a longboard) has what appears to be 50/50 US quarter sized radius right at the end of the tailblock with a big fin glassed in about as far back as it'll go. He says it's one of his favorite designs and that guy can SURF!
You sure can find a lot of pictures of amazing surfers surfing all kinds of waves with rail forward of the WP engaged, though, in all kinds of maneuvers.
Maybe tow-in boards and surfing are a little different than regular old surfing and surfboards?
I think this summed it up for me
“Hard rails don’t catch, bad rocker lines do.”-mark richards
rocker lines i,e, continous curve(school of Parmenter) versus staged (school of Mctavish) and foil/pitch (school of Loehr) are vastly under rated as to their contibution towards performance. I think Greg’s essay on the effects of pitch was one of the best.
most of the time we’re facinated by outline, rail and bottom contours versus the interaction of rocker, foil and pitch.
maybe its because it occupies most of our visual and touchy/feelly space…
I put the hard edge 17-18 inches up from the tail. It's a place to start and see what you like as you build boards. Mike
…hello,
several years ago we discussed here this stuff
then when B Burger arrived here, we chat again about (PM interchange)
if you ride toobs or stepped waves in shortboards go with tucked edge all the way
tucked to the nose
then hard in the tail or with a slight beveled edge
depends on what is intended for
To stop the “water wrap” in the nose that MC talks about I have a hard(ish) edge on the top deck at the nose. This gradually migrates around the rail and softens rearward. Thanks to Stump http://www.stumpsurf.com for the guidance on this.
But I like what I hear about edges. Too soft up front and there’s no feedback from the nose when coming around on rail. Time to get bondo out and build some edges.
“Maybe tow-in boards and surfing are a little different than regular old surfing and surfboards?”
Absolutely. All the tail slidey stuff and snappy manuvers we like to do in average surf conditions are totally absent in the tow-in world. And rails have to be designed with those manuvers in mind if that’s how the board is intended to be ridden. Round rails in the front without edges facilitate the forgiveness you need when the nose slips into the water laterally, often when the tail is forward of the nose. Edges don’t catch, they provide release and “lift” in that respect (not Bernuliian lift).
I was recently writing something about edges and referred to MR’s twins. That guy had remarkable insight as a surfer, and that showed in his boards as a designer/shaper. He doesn’t get enough credit, I think.
But my thoughts on rail design focus on rail shape transitions. What I think of as the “transition area” of the rail is that part ahead of the side fins where the edge rolls under and fades into a soft, round rail through the middle. This part of the rail has to serve a number of functions, which are different on opposite sides of the board. On the wave-facing side, the rail apex is cleaving water - some is held below the apex, and is fed into the edge, where it is cleaved again. Some wraps around the rail and creates what TW refers to as “suction.” But on the opposite side of the board, the rail has to shed water cleanly off the edge - multiple functions, multiple purposes, simultaneously. The pitch of the board, the angle of the board on a turn, the fin setup, the rocker and foil, all help determine what part of the rail is below the water surface and what part is above, which in turn determines the angle of the water flowing across the bottom of the board, and what part of the rail has to do what. So the transition part of the rail is critical, because that’s the part of the rail that you ride off of, for lack of a better word. You know that from the fins back is nothing but edge and release (for shortboards). It does it’s thing by itself. The front half of the board is nothing but soft, round, forgiveness, suction, and stability. You can count on it. But in the middle, that’s where you have to feel, as the rider, how the one rail shape transitions into the other, and how subtle shifts in angle, pitch, pressure, etc. effect the arc of the turn and the speed through the turn.
I like nose to tail edges. I built myself a 6’0 twinne that has them. But I don’t demand the same kind of performance out of that board as I do a performance shortboard.