Kneeboard Surfing USA Community Forum

I take a big breath and plunge in with some trepidation because of the sum of knowledge about spoons on this site and because mine is so limited.

Anyway, I've made a few boards using computer design and shaping machines. I've had an idea for a spoon for a while now, but haven't had the time to dedicate to it. I've put a pic of my basic idea up for comment.
album_showpage.php?pic_id=6757
NOTE: My idea is to emulate the spoon manufacture process from a positive by cutting the blank first and glassing on it. This should allow rapid evolution of design because there's no labour intensive moulds to build.
1. Cut the blank and glass the bottom and rails to stiffness
2. Then I intent to sand out the foam from the top all the way to the glass in the rear and shaping out the top-half of the rails. The benefit of having the blank preshaped is less foam to cut away at this stage.
3. Then lay up the rest of the board using conventional techniques.

Here are the ideas I've tried to incorporate in the design. Comments (especially from experienced spoon riders) are welcome:
This is an update of a '64 Greenough Spoon
It has more modern entry line and side-to side bottom curve, is 1' longer than GG's tiny things and 2" wider (21" vs 19")
The reasons for the width and length are:
1. Paddling in
2. Low speed carry over/ section connection
3. I'm 6'2" and like boards similar length to me
I don't know whether this is too much board
It's easy to adjust at this point - just change the specs in the software and check for anything wierd.

The plane shape has a bit of curve through it, but the shape's intended to be dynamic because of rocker and rail flex.

The entry is smoother, more subtle than the spoon-shaped bowl in GG's original.
The bottom is kept flat along the stringer line, but the rails are lifted higher than the stringer line - rolling the bottom slightly from rail to rail - but only by 5mm (1/4") or so at 1' from nose to 2mm (1/8") at centre point.
This differs from the boat-type bottoms on many spoons. My concern is that hull roll is important for initiating rail to rail transitions. I may not have enough built in.

The rails in the nose are soft and eggy. I'm not sure whether this is the correct way to go, rather than the "hull" concept in Terry's boards.

The rails are also not very thick in height. Since there is no top deck I'm concerned that water will flow over the top of the rail and into the top cavity, 'inverting' the lift. Hence the 6" nose rocker. But I believe that flex will take care of a lot of this issue.

The bottom goes flat after mid point.
The blamk design has 15mm of foam and no stringer.
The foam is used as a mould for the initial layers of bottom, then sanded away to allow glassing of the top deck. (how many layers of glass will this need, what are the distortion problems likely to be on 15 mm (3/4 inch) of foam? Should I have a stringer in the blank then cut it out?)

I think glassing is 18 layers of 6oz in the nose, gradually changing to 8 layers in the tail through a series of 4 vee panels (vee points backwards.
The vee-shaped panels create virtual stringer by putting more stiffness along the centreline.
I need direction on the number of layers and weight. Information about resin loading would be good (aka microlight manufacture) but I will refer to the other sites and forums before i do this, because i know there's info there.
I also intend to work with a glasser who used to glass spoons back in the day (but I have to bring him kicking and screaming to the table - he hates the idea of doing it again!)

That's all for now.

Red, so your "epiphany" back in March has materialized. Way to go! And you're asking for advice--nice. I hope a half dozen guys will weigh in and we don't confuse the heck out of you. Wherever there are three or four kneelos, there are five opinions.

When you talk about an "update" of gg's 64 spoon and a more "modern" point of entry: in terms of time it's an update but in terms of design it might be a step backward. I recommend that for this first board you stick close to George's design--it does work--there are no unknowns here. That will lower your anxiety level as you're building and guarantee you something that will be fun and look good. If spoons only cost $100 to make, it would be a different story but your investment in money and labor (as you will see) is too significant to experiment, at least on your first board. I think once you do the fundamentals, like a piano player, you can start composing on your own.

I like your outline. I salute you for going with 5'8" and being realistic about your height/weight. But proportionally I don't think 21" is wide enough. I would do 24". You mentioned something about 2" wider than gg's. His spoons mid-60's were 5' x 22". When you give the 19" measurement, you might be thinking of his later edgeboards (70's) where he reduced width and changed materials.

I would say your kick is too abrupt. You are inviting buckling issues, believe me. I would start the rocker at about 40" and go more smoothly to your 5".

The cross-sections are extremely flat. You said you were concerned about not incorporating enough hull roll and I'd say your instincts are right. The roll should begin roughly 6" up from the corners, about where your foam begins. If you make your rail line a gentle parabolic arc, you can use that as a point of reference for your roll.

Your concern about water flowing over into the bowl: it can't be avoided. However, it's not an issue. There's something about the design that compensates for it. If you have Children of the Sun, there's this short segment of Greenough at Noosa riding a little wave. The lip hits him in the face, he drops with it down to the base as the board is buried in white water and he puts it on edge anyway. If you watch in slow motion, you will see water flowing out of the bowl over the nose but also this tremendous rooster tail from the back end as the board powers out of the soup back toward the pocket. And it's a small wave. You watch and ask yourself, how is this possible? I'm your vehicle, baby / I'll take you anywhere you want to go...

"Virtual stringer". I thought the same way on my first board but I was wrong. You don't need it. If anything, you need virtual "ringer". It's a tuning fork design. The "prongs" flex independently. The strength is on the perimeter, not down the center. The "stringer" runs around the rim of the board. As Dale once said, the deck is just there because the rider needs a platform. The strength of the perimeter will be determined not only by the amount of glass on it but also by the shape of the rails. If you go with the velo design, they will be slightly rounded on the top dropping down into the concave of the bowl.

If you have to drag your glasser kicking and screaming into your project, it's probably not the glassing but the grinding he's screaming about. Tell him you'll do that part. He just gets it on there, you'll take it off.

As far as no. of layers, given the length: 8 of 6 oz in the hull, then 10 on the deck, then 5 strategically located strips on each of the rails. Remember, the compression side is the deck. For the hull I'd do 6 full-length up to the rail line, then grind out the foam and shape your rails, and then do the last two lams overlapping the rails. I'd make the last two 5'2" and 4'6" in length; in other words, short at the nose end. Don't worry about not lapping the end of the nose--you'll get it to excess with the deck. No grinding on the hull except to smooth those two lam lines.

Then I would do 10 on the deck full-length and 5 staggered strips on each rail to reinforce from the knees back. Then I'd get a long sleeve shirt and grind the living daylights out of it, but deck area only. Don't touch the rails, except to smooth and blend--leave all that glass on there. Start on the deck at the halfway point and gradually take the deck lams off, going from 10 at the knees to zero at trailing edge of the tail. Don't go through to the hull lams, though. Use a crescent pattern when you grind, sort of the opposite of your "v" idea. You can also grind off some layers around the inside of the bowl in the nose area and (carefully) those laps on the hull side of the rails. Keep your grinder an inch away from the rail line.

Fin--you didn't mention it. This is another story. We're used to small fins with minor influence. Here the fin is a major player. Don't skimp. For your size board I'd make an 11" with a 7" base. The panel would be 80 layers of 6 oz (we're talking polyester, not epoxy, all the way thru this board, right?). Once you cut the fin from the panel, you'd be going from roughly 5/8" thick in the base to a 1/4" in the tip. This is work.

You'll be able to keep total weight under 12 lbs if you do the requisite grinding but also **IMPORTANT** if your glasser always squeegees out the excess resin in each lam. Glass dry, make your sanding coats thin. The less resin you have in between the weave, the better. Ideally you want it only in the fiber. I know it sounds picky but over the course of 20 lams, the weight adds up. Also, poly is brittle and you don't want tiny shatters.

Check that "Spoon Fed" thread, if you haven't already.

Go slow, sleep on everything.

Prepare yourself mentally for 3-4 mos. of labor, if necessary--a Sept. finish.

Aussie hero, I look forward to checking in.

MOW thanks for all the info.
I think it's going to take me a couple months just to adjust the design (also have a 3/4 finished PhD thesis to get out the door!). I have a couple of other (conventional) boards to make before Nov to be ready for Jan on NS, so this is going to be a slow project - March next year (maybe) if I do the grinding - sooner if I find a fellow enthusiast with facilities (which i don't have).

The glasser spoke about (vaccuum?) bagging to get the excess resin out.
'plane makers get optimal resin loading figures and weigh their resin out - that's how much they use to get the best strength/weight ratios.

I've printed out your advice and taped it to my headboard for inspiration

Tx

Your glasser's right. It would be interesting to see what technique he uses to vacuum bag so many lams in so many stages. Or maybe not

Swaylock's probably has the subject covered. You can leisurely read up over the next year. Always know more than your glasser.

well ...ill probably have my spoon done before yours red......ive been fortunate enough to have been in a Plastics ROP where i shaped my first skim/hand boards out of PU,GLassed em with 6 oz and polyester....and observed vacuum bagging auto parts with fiberglass/carbon fiber/epoxy.........
...ive got the fiberglass/pump/blank and when i get back from mexico ill devote lots of time to the prodject....i started a vacuum bagging thread at flexspoon.com a while back....i havnt checked it in a while maybe some good info there......
peace

hi Red

good to see your enthusiasm never wanes

I am moulding up some fins (have the female part done = ie the easy part)

this reference is interesting but maybe not relevent ( interesting parts about body molding)

but may help down the track

http://www.solidsolutions.com.au/cat_main.htm

(but when did 'relevance' ever matter?)

and is a mould the same as a "mold"

retrograds

GG once told me he liked to use 20 year old foam, taken from a stripped longboard.

He said it was nice and hard from curing so long and the old PU foam formulas were'nt too concerned with being ultra light.

From internet cafe in Puerto Escondido so keepin it short. Surf has been too big to go out 20 to 25 foot semi close outs. Literally shake the beach. HI north shore power. Made my knees weak watching from the beach. Spent some time down coast at Zipolete aka playa de amor but locals say native indian word means beach of death. like Zicatele but has huge rocks at one end and the most ferocious under tow imaginable. 2 to 2 people per MONTH get dragged out and pounded to rasberry jam death on the rocks. No lie. Strong swimmers too. Watched couple loco local kids give it a go. Booger made the human starfish in the lip. KABOOM! came right in. WHEW. none for me. Just found a nifty little point break much smaller but its been pouring rain and sewer water run off so no surf for still afew more days. oh well . Food is insanely good. burp.

Coupla quick thoughts on spoons... Based on my experience riding my edge board i´d go with a bit thicker rail. About like a stand up long board, i.e. 1.75 to 2 inches thick before rounding it off. Lots of foil down to about 1 eigth thick at the tail. Mine i think too thin and tend to dig into the face. Fine for reeling power barrels but be realistic about what you will be surfing on most of the time. Also, if full displacement type hull and not edge board, id go with the mellow velo type of mostly flat in the middle and just rounded soft under the rail for short distance in. This will make it work much better in more variety of waves. Recently watched Children of the Sun and State of S and seemed to me that even in fairly good sized waves GG was loosing speed and sinking a bit at the last part of tight cut backs. i saw him at huge Rincon and not a problem but those were BIG bigger waves and really hurling w- power.....

Maybe I can come up w- more trash and ideas when i get back to the good ole USA...

DrStrange, south of LA (and then some)

thanks for the input
Still trying to get my head around putting vee into the tail (after MOW's comments).

My primary idea is to build a flexible bottom that learns from the past 30 years of surfboard development (with all due credit to the original spoon concept).

My preference in kneeboard bottoms is for rolled underside in front 1/3, flat through entry to front of knees, subtle vee from there to max at fin centre to flat in tail.

My preference for rails are soft at front with the centreline decending toards the tail. Down rails aft of knees.

The rolled entry and soft rails are designed for forgiveness in the front (no rail catching).
The down rails are designed for lift aft of the knees. They help a little with grip in turns (but this is over valued, in my opinion).
The flat lead-in before the rocker low point overcomes a lot of water entry problems. The vee rear enhances water exit. So the bottom's designed to aid water flow past the low point of the board (under the knees). This limits the tendency to push water so the boards travel (in trim) at low speeds and over flat sections.

I know that many people won't agree with this model of water flow, but it works for me and these are the design principles I see in all the best kneeboards.
I see the flex concept adding to this core principle by providing dynamic rocker and rail outline. This means that width (and parallel rails) can be maintained through the rear of the board which should lead to unbelievable speed. Dynamic rocker and rail should provide turnability.
My concern is not whether it will work (or even whether it is an improvement), but rather whether it will be too fast to turn and whether it will project too far out of the pocket.

I'm going to spend time on an original Hayden (to try to save myself making a reproduction of one) and then try to reconsile the above ideas with what I learn.

The info I'm getting from you guys is an invaluable contribution to the process.
Thanks

Red, your commitment it inspiring, if [ a big if ] you can afford to experiment on such a huge project you should push the envelope.
George's boards worked but who knows where some new thinking can take the spoon. Look at the body board, no fins and v rails. I've often wondered
how a kb/ bb hybrid would go with a bit of evolution, incorporating v rails
into the back 1/2 of a kb with a diminishing v rail to a full resin flex tail.
Why not ? Anyone care to comment ?
i think you should go for your ideas, you wont find out by compromising.
AB

Red

Good luck with your endeavours. Your earlier comment go me thinking:

I know that many people won't agree with this model of water flow, but it works for me

It does seem to me that the 'artificial contruct' or model of water flow under a board does help one's undertanding of surfboard hydrodynamics - however maybe I'm stating the obvious in suggesting the front half of a moving board cannot direct water though the rest of the board and the fin area. Presumably the front half of the board is planing across the water which has its own momentum or inertia. It may create some surface turbulence which may or may not assist the function of the fins as they slice through the same area of water.

I'm not quite sure of my point, but I have a feeling that the 'water flow' model is perhaps not as helpful to the design process for the front half of the board as it is for the rear half, particularly the fin(s).

I see the flex concept adding to this core principle by providing dynamic rocker and rail outline. This means that width (and parallel rails) can be maintained through the rear of the board which should lead to unbelievable speed. Dynamic rocker and rail should provide turnability.

Red, to add to what Shelfbreak said, my fear is, with that width and those parallel rails thru the rear of the board (which is as it should be), your low forward rails are going to stick and track as you start to roll over. Unbelievable speed is fine as long as it doesn't go in an unbelievable direction.