I wanted to ask you all for a little advice about my new project if I could.
It’s my fourth board and this time I want to shape an all-round shortboard for waist to head high waves. I want to move away from the flat bottom to vee on this one so have decided to try my hand at a single concave, starting 12” from nose, 3/16th at the widest point which is 2” behind centre, to flat behind the back fin.
I’ve read loads in the archives about rocker and concave, there is a ton of info and some of it quite baffling, but came across something from Gregg Webber. He wrote about how making depth of concave equal at points with the same width created a large sweet spot, e.g. 1/16th deep where the nose is 12” wide and the same depth where the tail measures 12” wide. I think I will give this a go and see.
My blanks have arrived and am about to make my template but before I start ploughing into it I wanted to show you my design and get a little feedback.
I think the plan shape, depth of concave and its placement is O.K but then again I don’t know squat…and my real concern is with the rocker, especially entry and tail.
As it has been said here before, get your rocker right, the rest is just bells and whistles.
I would really appreciate any contribution. I’m thick skinned and won’t take anything personally, honest!!
I have seen some of the awesome work in the build threads, particularly Bud’s…I want to get that good! Please help!!!
I’ve uploaded some images from shape3d. I’ve used Greenlight as a reference for the rails and went with the medium on their chart.
Off to work in about an hour but will reply to any posts when I get back.
Something looks wonky about your outline to me. The nose doesn’t look right. I would skip trying to create a computer file and go to blendingcurves.com and simply download a good template that is ready to go.
Yeah, that’s the one I had a quick look at actually!
It definately has a narrower nose. I’ll try and use the superpose function on shape3d to get a better look at the difference and see where I went wrong.
Not sure if the plan shape they have is true to scale though so will print both noses out and compare that way.
Thanks very much for the link Mako!
I read about the relationship between nose and tail widths here: https://www.swaylocks.com/forums/first-board-egg-shape-template-need-opinions
The post is about an egg and a tip given is that the nose shouldn’t be more than 2" wider than the tail or it will ride nose heavy.
Would the principle also apply to hp shortboards? Nose should be at least 2" narower than the tail??
Numbers are an aid to your eye. No matter what the widths are, you’re surfing the curves and flats. (profound, eh?) You can hit the tail, wide point and nose numbers you’re looking for and still end up with a funky curve if the length doesn’t fit them, which to be honest is what looks like is going on with your template. In that length it looks like the nose width and curve in the front half of the board doesn’t fit the curve from the wide point back. TO ME, anyway.
That wasn’t the question you asked, though. As I understand it, concaves flatten the rocker along the centerline whilst retaining the curvier rocker at the rails. The typical rocker for a design using a heavy concave will have higher lift at both ends.
When you design a board in CAD one thing you need to be mindful of is that you’re going to need a blank that can accommodate your rocker and foil. That can be a challenge.
Since you and Mako have replied I’ve tinkered a bit and had a close look at the nose, went to Blending Curves to compare, and reduced the width to 12 5/8", looks better, but to be honest I find it hard to notice on the CAD image when something is off as you both did. I’ll upload the image when I get on the PC.
I think I have a medium rocker so, if I understood your advice correctly, I’ll reduce the amount of concave too. Thought 3/16" was pretty much standard for small wave designs but I suppose you have to marry them up to the correct rocker…I have a lot to learn.
Blank wise there is a relatively new company here in Spain called Blankers that does blanks that are thicker than most so no worries there. I checked before I ordered 'em and they will accomodate the shape.
I really appreciate the help! Back to the learning curve
After looking at the link Mako posted and listening to his and gdady’s advice, the nose is now narrower by 1/2" inch, I can see what you guys meant, the curve definately flows better than before. I’ve also reduced the concave depth to 1/8" at wide point and adjusted so it flows evenly along the whole length of the board following what I read by Greg Webber. Here’s the new version:
If you want to experiment with the heavy concave just increase your tail rocker. As for blanks, you just want to choose either a stock blank that has a similar rocker or else figure out what kind of adjustments it would take to the blank to get your rocker. My preference is to adjust my designs to my blanks because I’m pretty sure all those designers are smarter than me.
As for your template, I’d have bumped the nose out a little. Either that or extent the curve of the middle control point forward more. A little adjustment there will go a long way.
The blank I chose actually has an almost identical rocker to the design, only its a 6’4", so that is pretty good. Should save me some bother.
" My preference is to adjust my designs to my blanks because I’m pretty sure all those designers are smarter than me." Me too, I adjust my designs to the blank more now. Had to take rocker out of one for my previous board and although I managed to do it, measuring a lot, it was a bit hair raising. Once I improve I might get more adventerous hahaha.
I’ve gone back and played around moving the centre control point up a little but have settled for increasing the nose by 1/8" to 12 5/8".
I’m a little worried about increasing the tail rocker in case I make the board slow…would the increase in concave depth help in not slowing the board down?
I think that what you’ve got will work. I also think that if you bumped the tail rocker by 1/8" you could add more concave back in without slowing the board down.
But definitely get some other opinions on it because I normally stick to flat bottoms and lower tail rockers.
Shape looks great to me, assuming it is in-line with your weight/ability level. The thing is, if you are hand-shaping it, you are not going to nail the exact specs on the Shape 3D file anyway, especially if this is only your 4th board. If you are really keen to nail all of these dimensions, then (gasp!) take that Shape3D file to a cutter and get the file cut. This way you will have a much closer representation to what you designed. If you’d rather hand shape, then keep in mind you will be lucky to get within 1/8" of your desired dimensions other than perhaps the basic outline widths. You need to keep in mind that designing/shaping your own quiver is an iterative process. You need a baseline shape (like this one) and you need to surf it a bunch, then decide what is lacking. Then you can try to address the shortcoming and make an adjustment and make a new one (don’t change too much at once). I’m no pro but I’m closing in on 100 boards shaped, glassed, sanded and that’s my .02.
Cheers for the comment Jamie, your 0.2 have gone in the piggy bank!
No CNC machine, will hand shape it. I use shape3d to get an image of what my design would look like, plus I use it to print out my template. I don’t really know how to use it properly so what I get out of it is a rough picture. I try my hardest to hit the rocker numbers though but am under no illusion that i will be spot on with anything. My last board came pretty close so want to improve on that with this one.
I bought two blanks for the reason you mentioned. My plan was to make this one and test it out, give it to as many people I can to ride too and get some feedback so as to sort out what sucks and hopefully improve it on the next one.
I think both of your templates look fine. Those lines representing the toe-in and the thickness/cross section can really throw off your perception. Chances are you’d not notice much difference between them if you just jumped on blindfolded and rode them.
I’ve made my mind up to go for the narrower nose.
Do you think the rocker looks good, John? Was thinking of doing as gdaddy mentioned and increase the tail rocker to 2 3/8" and try a 3/16" deep concave.
It’s the first time I’ll try shaping a single concave, maybe it’s a bit ambitious.
Rocker looks good either way as well… go for it! Build it and ride it - you’ll be stoked. It looks like a great design. I’ve been known to say that for every single design change you make, I can probably change something else to equal it out. Fin adjustments are always your friend if in doubt.
If the plan shape and, more importantly, the rocker looks good it’s a go. I’m happy with the volume, my other board is 38/40L so it shouldn’t be too bad.
I’ll try the increased tail rocker and deeper concave and see what happens. Will post some photos when I’m done. There are a few firsts for me on this one, first time using an electric planer, first hpsb, first time shaping concave…I might be a while.
Bravo! Check out Youtube and watch some shaping videos. I learned to take shallow cuts and work my way from the edges to the center of the blank in ‘steps’… make your first cut, place the front shoe of the planer on the ‘step’ created by the first cut, and proceed to continue that method until the surface is even. Also check out the Bill Barnfield rail band thread. It is very enlightening in regards to shaping the rails with a planer.
