Diamond rails?

General Discussion
1

Hi,

Has anyone tried shaping surfboard rails like boogie board rails, with 1 rail band on each side similar to a diamond shape? What would be the drawbacks of such design? When building model aircraft wings I used standard wing foils and also tried “diamond” foils and they worked very well, providing lift and nice flight characteristics although they weren’t made to go fast, but surfboards don’t go fast either. Boogie boards mostly have that rail shape and they hold onto the face of waves, so I can’t see why such a rail on surfboards wouldn’t hold. What do you think?

2

I have never shaped a board like that, however, I would imagine that because of the length of surfboards and the twisting and flex patterns, that the sharpest outer edge would be the weak link and split at some point.

I regards to strenth, if you look at it from a engineering point of view, an archway has the greatest strength. Kind of like the strength of an egg if you put it between both hands with both ends in your palm, it is extremely strong and it is hard, if not impossible to break.

And boy, glassing and sanding might be a bitch hu?

This is just my theory, and if anyone else has the experience to prove me wrong than that would be helpfull.

3

I agree with you about the mechanical aspects, although the middle edge doesn’t need to be too sharp as it would make it brittle. As far as not being an arch, this shape is approximating it, and I’m not sure if that would change too much the flex pattern of a board.

Independently from that, I would like to know what you think about that shape for holding onto the wave, turning etc… Why would they work on boogie boards and not on surfboards?

4

I’m no boogie rider, so my understanding is limited, but boogies are generally much shorter than surfboards and the rail seems to hold in partly because you are laying your full prone weight on it.

There is a lot more finesse to stand-up surfing, and so a more sensitive design approach is necessary. I tried a rail not unlike your example, with hard edges, and I didn’t like it. I then fixed the rails back to a normal shape and it then worked well, same board. Worth the experiment though.

5

That kind of rail sounds similar to what Y (tom morey) has put on his recent “swizzle” boards, not surprising since he invented the boogie board and is always trying crazy stuff. Have a look:

http://tommorey.com/yhp7.html

6

Has someone tried the Tom Morey board? How did it work rail wise?

7

PierreK,

My memory is unsure, but, as I recall from a twenty year old article in WindSurf magazine, George Greenough did a number of experiments with up styled rails and had some interesting opinions. Perhaps you might want to try contacting Dale Solmonson-he may know of the date of the article.

In any case, give it a try. It would be interesting to hear of further results.

Have fun. Patrick

8

I’m guessing but I would say that a rail like that would make the board surf too high in the water and you wouldn’t have a feel for the wave. I would also bet you’d be digging the rail if you tried to crank a hard turn. Would the rails be like this the length of the board? Or would they soften to the nose? Interesting.

Quote:

9

Hey Pierre - The should be some stuff in the archives about “chines.” I made a board last year with those types of rails, and added “strakes” after glassing, to get the sharpe edge. For rail to bottom to rail, and hold in the face - it made a 22" board ride like a 18" board, and had better hold in the face. Great for tube riding. Adding the “strakes” the hard, 90 degree edges, is a bit of work, but, from my understanding, is also key to the speed while planing on the bottom, keeping the rails “free” from sucking into the face - until you want it, then the narrow bottom allows you to put it on edge with ease. Let me know if you want more details, if you can’t find them in the archives… Or, you could take the time, because he is so busy, to contact Dale Solomonson, as he knows quite a bit about the design.

Good luck, Taylor

10

Ssomething to keep in mind is that the bodyboard was designed to work without fins. The diamond rail was more or less the first variation to the bodyboard rail from Tom Morey’s original angled rail. More info is available from various bodyboard sites; a good place to start on that is ebodyboarding.com.

11

PierreK,

Steve Walden in Ventura Ca. has a creation called the STEALTH. Very straight lines and sharp body board style rails. By the looks of the boards, he seems to be constantly modifying them. I hear that they are quite fast and maneuverable but man are they UGLY! There’s a couple in the back of his shop that anyone is welcome to look at.

Sr Pato

12

We made rails like that on one guy’s board, and it was loose, bounced off the wall on off the lips, never stuck even tho he favored front foot all the time, and was fast.

Allowed for a flatter than normal rocker, so worked pretty well.

Only ONE board thos, as we didn’t want to sand the boards, and we changed to narrower noses and tails, keeping the WP the same, which in effect, loosened the whole board.

As for body boards, try riding a wave without your swim fins, the board just drops off the face sideways!

Every boogie boarder keeps his inside swim fins in the water, and his leg if he prones, to give him direction.

Drop knee guys ALWAYS drag their inside fins! Always!

That boogie rail is made to go sideways, when no fins are used!

13

LeeDD-

My experiences with finless prone craft have generally been the opposite, including inflatable surf mats. Slippage is more often the result of poor design, inadequate rider balance, handling and edge control. Many skilled prone surfers use their lower legs, feet and swimfins as a means of counter-balance (slightly above water), but rarely for directional control (dragging in water)… reserved for a last effort.

From its origin, the beveled rails of the flexible foam bodyboard have been influenced as much by mass-production techniques as by design choice. But beyond the ubiquitous angled rails, there is a wide spectrum of more subtle and sophisticated edge contours that are very applicable to prone use.

“As for body boards, try riding a wave without your swim fins, the board just drops off the face sideways! Every boogie boarder keeps his inside swim fins in the water, and his leg if he prones, to give him direction.”

14

I don’t think body board rails apply to inflate mats, because mats have channels between the ribs, for a fin and directional affect.

EVERY body boarder drags his fins and his thighs, and when they don’t, they do 360’s!

The drop knee guys are a good example. Notice they always drag an inside fin, the outside leg is up standing, but the inside is dragging thru the water for directional control.

I don’t boogie very well, but we have a spot we can walk out past the waves and jump into the green water before it breaks (wave going sideways past land). When we don’t use fins, we have to be extra careful to drag a full leg to get and stay high to make the wave.

When we DO use swim fins, we drag the inside swim fin.

Body boards by themselves, with no rider draggin behind, just drop sideways or spin into a rotation.

15

LeeDD-

As I said, my experiences have generally been to the contrary. I’ve designed, built and surfed a wide variety of body boards in all sorts of waves… about 25 years’ worth.

When I began bodyboarding I also had slippage problems

which were soon resolved by thoughtful practice, esp. in regards to balance/riding position. Later on I began experimenting with different designs, materials, means of construction, all having their influences.

But… even when surfing on a simple, flat piece of waxed

1/4" plywood, drifting/side-slipping are seldom more than a function of skillful edge handling. Frequent, dependent dragging of legs in the wave face (or any other part of the body) for control are usually a mark of inexperience.

FYI, the bottom/rail contact surface of a modern (low pressure) surf mat in trim/motion closely mirrors the curves and textures of the wave face… softly flattening, nearly causing the channels and rounded chambers to disappear. Rocker, torque and profile, template, rail contours, buoyancy distribution all change instant by instant. In active contact areas, the deck and bottom surface move closer together under pressure from wave face, centrifical force and rider’s body, compressing the inside rail/deck… w/the round inside rail tapering down to thin, flexible edge.

Extending/dragging off the back of a prone craft can also mean the vehicle is too short for the rider. This problem is more easily observed with bodyboards, paipos, bellyboards (w/rider pulling up on front, head/chest up, hyperextended neck/spine) which are commonly ridden more off the tail.

16

Kinda hard to prone 100% without dragging anything on a body board.

Yes, once going fast with direction, low on the face, you can try to lift 100% off the board, and still maintain trim and direction, but once you lay that rail in to turn hard, it just drifts without a directional fin or leg or both, in the water.

Once again, mats have ribs and also conform to the wave. Body boards do not.

Most good paipos are really wide aft, and the rider positions himself accordingly, and drags his fins for directional control.

My experience with diamond rails, hex shaped, are with mid 6’ long surfboards.

17

Coming from someone who used to bodyboard often:

On very large or very steep waves, dragging the fins helps to lock you into the wave, but actually slows you down on directional changes.

It often isn’t necessary to drag the fins. This is coming from someone who bodyboarded a lot (before I got into surfing).

Dragging the fins, of course greatly slows you down and usually you lean your weight on your inside rail. Watch professional bodyboarders. Fins are rarely being dragged at all.

Fins are often dragged in the water to stall when trying to set up for the barrel.

18

" It takes years to become really proficient at anything. Learning how to bodyboard really means learning how to control water flow over your board and body; the regulation of drag. Notice the air pocket along the rear portion of the rail in this photo. The “vacuum track” is in effect as water coming off the hull tries to stick to the rail, creating that suction we all know and love. Check out the shear-stream bubble coming off the front of the board at the chine. This is where un-aided spinners begin–using your rail, not some ungainly human extremity. If you want to go fast learn to reduce drag. Make your legs invisible."

Mike Stewart

For reference see: BodyBoarding Magazine, April 1998. “Stewart Style” article by Mike Stewart with photos by Scott Winer. Courtesy Neil Miyake, http://www.hisurfadvisory.com/

19

Fancy thoughts and impressive quote, but do you really think good bodyboarders DON’T drag their thighs, lower legs, and fins?

Do they magically cut their legs off at the thighs, or raise it straight up into the air, to use only the board’s planing surface and rails?

Better you look at some pics of bodyboarders. They all drag their legs and at least one of the fins when riding at an angle.

No, they don’t stick a hand out to initiate turns, but I also never said they did.

20

LeeDD,

What you’re saying is that this board with angled rails was a good one, so maybe it’s worth trying? As far as rail shape, I think that a surfboard with rounded rails would slip as well without fins on it, so I don’t think slipage on boogie boards is a function of that rail shape. So the swim fins would act as stabilizers but those angled rails still hold on the face just like rounded rails, isn’t it? Why do they stick on this rail shape? easier way to produce the boards with hotwire cutting?