Anyone out there?

yep, looks like it should work, but it's hardly hollow, there's more stringer than space. Well that's the way it looks to me.

Well it's supposed to be a thin sheet of carbon or glass layed up in a 'corrugated' shape so it shouldn't weigh much.
I guess I'll just have to try it and see if it works!

Anyone got a fibreglass waveboard mold?

OK, I get it, nice bit of lateral thinking. It would have a bit of give, and not produce too much of a point load at the joins to the skin. Making the mold for it could be a bit tricky, (it would need to be within a millimeter or so otherwise the bog will weigh too much), have you used any of your lateral talents on that problem???
How about carving the +ve out of foam, using that to make the -ve hull moulds, divynicell the bottom, then carve the corrugations into it, right down to the dcell. Mould that and the corrugations would be the thickness of the layup bigger than the hull mould. Could work, want me to shape you some foam?????

Ok I see the stringer happening like this.

3D model the board including the wall thickness of the skin sandwich.

The void inside the model provides the outer dimensions of the 'stringer'.

3D model the stringer within those parameters.

Have the shape cnc'd into a block of MDF. That's the mould for the stringer. Just prep it up, slap on an e-glass or carbon triaxial or double bias about 150/200g, trim it and glue it between the board halves.

Bobs your uncle....

Need to reverse engineer a good board shape though... I think I know someone who can do that...

Ah, so we've left my century behind, I keep forgetting that!!!
So you scan it in with a laser????

Copyright issues?????


Have you worked out the weight of the stringer? Had a thought last night that it might way more than a kilo if so you wouldn't have any weight advantage, but mass production costs would be very nice.

Hi Decrepit,

Time marches on mate....actually I'm just lazy and prefer to let machines do all the dirty work!!

There are set ups out there which can reverse engineer a 3D object sort of like CNC cutting in reverse. You put the tip of the robot arm (or whatever bit of hardware they use) onto the surface of the object you want to copy and it records that point. When you have enough points logged you can use them to generate an object in your 3D workspace.

I contacted a mate yesterday who has a fancy robot arm cutter but he said he can't use it to reverse engineer, he does know a better way to shape a board in 3D space though, using a shaping program he just enters the required length/width/rocker/rails etc.etc. and gets a cleaner model to CNC with.

Hadn't worked out the weight of the stringer, but if you say it's area is roughly 1.5m sq and you use 200g cloth @ 1:1 ratio (may not need it that heavy)that would give you about 600g.(?)

Guess it's pretty hard to copyright a boardshape as they all have very similar shapes (in a general sense)I wouldn't rip off a board exactly anyway....just pick my favorite and 'improve it a bit'...

So what shape would be perfect? That's the big question.....

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Originally posted by sinker


Time marches on mate

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Tell me about it!!!

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Hadn't worked out the weight of the stringer, but if you say it's area is roughly 1.5m sq

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Think it's going to be more than that, my 8' mal's bottom is 2m2 and you have the corrugations, may be over 3m2.
WOOPS, that's the other problem with getting old, (the silly old fart syndrome) the mal's total surface area is 2m2, so 1.5m2 could be close.

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and you use 200g cloth @ 1:1 ratio (may not need it that heavy)that would give you about 600g.(?)

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That's another thing that worries me a bit, the stringer is mainly in compression, and none of the resin/fiber composites are that good in compression, so I'm not sure what you'd need, maybe you need to experiment with a small section, or ask an engineer.

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So what shape would be perfect? That's the big question.....

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Don't think there's such a thing, it needs to be optimised for conditions and sailor, more rocker and v for higher winds, thinner rails for lighter sailors etc. I have 3 waveboards, (well my wife shares 2 of them with me) bigone for 12-18knts, midllesize 15-25 small 20 upwards, sure you can have an allrounder but it's not going to be as good at the extremes as the big and small.

Aaaah, that endless open question, should I go trad wave for max hi wind wave performance or widen and flatten it a bit for a more all round board and lose some of the edgyness...!??

If I can keep you talking about this long enough I can avoid actually having to build the board at all..!!!

That doesn't sound right, the more we talk about it the more you should want to build it!

Have you tried thrusters??? Could be the answer if you only want 1 board.
In theory you could have enough toe in to make a nice loose wave board out of your wider flater all rounder, especially with a smaller center fin. Remove the outside fins, and go back to a normal center fin, and you have the blaster back.

I modified a board several years ago, but I must have got it wrong, didn't work at all well, so I've stayed with single fins since.
What would be nice is adjustable toe in, but so far I haven't figured an easy way to do it. A wider box is probably part of the answer.

Bob McTavish (Ballina/Byron Bay)made hollow semi production epoxy course racing and slalom boards in the late 80's. I used one of the demo course racing boards in a race series. I must have put a crack in it because as I came into the beach I couldn't pick up the board it had gotten so heavy. I emptied about 20-30 litres of water out of it. At least I had something to blame for me going so slow

At least you could empty it!!!!!

Hi Juice,

Man, those grainsurfboards are labour intensive....Pretty finish though!

Sinker once all the templates have been made up then it might be less labour intensive. I think making a mould would be quite time consuming especially working out the tight tolerences and expensive, also you'd only be able to make the same shape so the board would have to suit the masses no room for customising.

Yes, grain boards look great, but I couldn't find any mention of their weight. Don't think they'd be all that light, any ideas???

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Originally posted by decrepit

Yes, grain boards look great, but I couldn't find any mention of their weight. Don't think they'd be all that light, any ideas???

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I heard they came in at 27kg.

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any ideas???

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Yes keep the concept change the materials

FYI, the Grain Surfboards weigh approx:
5'10 fish 10lbs
6"4 fish 12lbs
10' nosewalker, 22
6'9 singlefin 14 lbs

on average about 1/3 heavier than foam/glass

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Originally posted by decrepit

Yes, grain boards look great, but I couldn't find any mention of their weight. Don't think they'd be all that light, any ideas???

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