Hey there,
I am designing a board when surfing conditions are small, powerless and mushy. At tail, I will put a spiral vee, and then A generous single concave runs the whole length of the board, with a slight double within the single between the fins.
I would love to have some feedbacks.
Aloha.
Eric
Eric, Eric, Eric,
Why so busy a bottom, on such a short board, intended for marginal conditions? A smooth flat bottom, and a single fin, are your path to success. Your ignorant peer group will mock you, but you will be catching waves, while they wallow in the mush.
Ignore the master at your peril.
Concaves work off the power of the wave. Gutless waves by definition have no power. Go flat. Not a fan of single fins on short boards, but it wouldn’t slow you down.
Flat bottom with a really subtle chine at the rails to smooth it out a little; keep the edge for release. I would do literally ANY fin setup other than a thruster or a bonzer on that shape and for those conditions.
I had a board very similar to that, but longer at 5’4" x20.5 and flat bottomed. I remade it with a double to vee, then I remade that with a double to vee but moved the concave up further and altered the rocker to be rounder, made it an inch shorter and gave it a slight wing at the back to skinny up the tail. All of them were 20.5" wide with a 17" tail at 1 foot up. The first two were taken out of longer blanks and the most recent (and best) one was from greenlight’s 5’3" blank.
It’s hard to completely separate variables, of course, but the flat bottom is faster if you just cruise. The concave versions definitely produce speed better if the pilot is moving the board around and pumping. The concave versions also have a different feeling on the water than the flat one. I don’t think the flat bottom suited my style of surfing. But do be cautious of trying to shove a ton of contours into such a tiny board. You really have to be good to get that all to flow nicely in such a short space. It took me one board to realize I could do the concave better, and the vee is very slight. My double is quite deep and that’s basically all that’s going on there. Blank choice is very important too, but of course it depends on your rocker.
Consider a quad too. Mine’s 5 fin but the quad option is really great when it’s small.
Couldn’t say it any better myself. Nuff said. Listen to Bill.
Hi thrailkill,
you are right why bothering with concaves for a surfboard which is designed for small mushy surf conditions. Let’s do this one with flat bottom.
I like your point of view and your feedback. I think I will do this one as flat bottom and later redo it with concaves just to see the difference. I have never surf a board with flat bottom. I am kinda of surfer who likes making curves on waves. I will go for a five fins setup 
…Take the concave’s out, remove your 3 fins and put in a single fin… ?
Really?
I’m 72kg and the fastest boards I have, are small wave, sub-knee to over head waves. they both have a strong single concave the whole way through in a double between the fins. one is a Twin performance/keel fin, and the other a quad.
concave is 9mm/ -1/2" deep
This one is 5’1" x 19 7/8" x 2 7/16"
… If you can surf a wave concave’s will boost your performance. but if you want to ride a wave, then, maybe a single fin is for you.
Run with it mate, or are you the later?
Aloha yorky,
Many thanks for your feedback Your post makes me think about. Now, I am shared removing or not the concaves to go with a flat one. Looks pretty dope your board. I can see on the pic the double double concave running through the fins.
For sure, I will not setup as a single fin, I am not a fan of it.
Love the planshape. Follow Bill. The only thing I would add is volume in the tail. No need to overly foil the tail of the board. The extra float will allow easier entry and paddling. Looking good so far.
Hi gunkie,
Thanks for your feedback and advices. Will you go with concaves as I did or with flat bottom?
Wide tail mushy waves like rail fins; keel or quad
concaves are a control feature, flat is maximum lift
