I did my bottom contours today on my small wave fish type wide nose wide tail thruster to be .
This is my first attempt at contours so I took my time and set out after a single the length to a double out the tail. But as I was shaping I put in a flat middle for speed at the last minute. So It goes single to flat to double .
Now I am thinking this might not be a good idea. Is this a ok combination or will it mess up the water flow from my single to the flat??/
Oh, And thanks for all the help so far guy’s. YOU ROCK!!! My first board was just flat all the way. It rides good but I want to expand my shaping
In my riding (rather than shaping) experience, pulling the water in (with a concave) without letting it out (putting vee under the fins or flats in the low point of the rocker) makes the board push water because it has no where to go.
I’d worry less about channeling water into the intake and more about exhausting it efficiently.
My 0.05c (all 0.02 value of it :!)
I’ll try to give you my 2 cents and maybe some of the production
guys can chime in as they have lots more experience and feedback
from their riders.
I’m glad your first board rides good. Bottom contours are one of
the most difficult aspects to understand as they are also influenced and
contribute with rail shape to make a board work well. Everybody seems
to put concaves in without understanding what they are doing.
If you are putting a concave in a board 6’ & under, I would recommend
that it should be greatest
under the front foot and almost disappear before the rear fins. On a fish
style board, a concave in the nose will suck down (a concave is always
slower than a flat) and the transition to flat will push the water trying to
exit the concave making a board harder to drop in.
I woud recommend that you go from a flat nose to a slight concave (1/8")
maxing out under the front foot and extending from the lap line at the rail
across the bottom and fading out at the rear fins. A panel vee will help
the water exit as the board is placed on a rail and a spiral vee (vee with
concave) will help maybe a little better. Cant on the fins is also important
if you are planning or riding the board in anything bigger than 2’ beach slop
so watch that if you are concaving thru the fin area. There is lots of info
and suggestions in the archives on fish and fish bottoms so be sure to read
up. Personally, I have found that small changes in bottom along with a specific
rail shape will create a vastly different type of board all other things being
equal! Good luck on #2!!!
Waldo, I’ll have to differ a bit with what has been said so far.
According to an “established” shaper I know, concave to flat is very good. The secret is to not bring the concave to a teardrop as it heads toward the back of the board, but blend it in gradually accross the width. This will allow for the escape of the water as mentioned before. Flat in the middle going to double concave over the back foot. And here’s the Big secret: flatten the rocker just a little right over where the surfer will be standing. Makes for quick speed adjustments. I’ve tried all of these elements and they work well.
Doug
SurfTeach. What if my board is a 6’8 .It is a 6’8. What would you sugest then? If you would please?
Wow , A bunch to think about when it comes to concaves. Length, width , depth, what type where. I’ve read here it’s a life time to understand it all and then it isn’t enough time . I can see that. When I was shaping my double out the rear I started thinking. What if I kept it a double concave but lowered the sides abit with the stinger a bit higher like a V but it was still a double concave . Then all the variance off of that. YEE.
Gave me a head ache.
Thank you guys for your input so much as it helps so much and saves a bunch of time.
So Doug I followed the shape of my board and double contoured it out the tail. So it brings it wider to narrow as it leaves . So maybe I should nip the sides down a bit to release water rather than funnel it ?
Waldo1 - I’m having a real hard time agreeing with some of the responses here , so let me suggest that you grab a straight edge and go to a shop with a good selection of the more reputable shapers boards. Look at what they are doing and I think you’ll see a lot of commonality from the big guys. They’re not going to hold back and make inferior stuff. Or you could try to reinvent the wheel. At this time the big names are all, for the most part making single or single to double concaves, almost no concave in the nose, about 1/8" under the front foot, deepest around the side fins- about 3/16" or a tiny bit less and slowly fading to flat about 3’ from tail ( maybe a tiny bit of v in tail if you need it to loosen it up) There’s got to be a reason so many of the boards are similiar.
Waldo, Regarding the tail: What is most common is to flatten out the concave as it reaches the very back of the board. However, the Bonzers and some other designs carry the concave all the way back and out, so when you look at those boards from the back there is a definite double-arch look to the bottom. Different purpose in mind. I’ve never shaped deep concaves all the way out so I can’t comment on the effects.
The tail double concaves can come to a kind of teardrop and still be effective, because the pointed part of the teardrop is very shallow: almost flat. Where the teardrop slows the board down is in the front. But that can be good if you want to noseride. I don’t do teardrops in the front any more because I’d rather have more speed.
Doug
Woops - after re-reading your original post I saw the ‘fish’ word. That changes things depending on how wide you go, however concave in front of flat may work against you. The concave in front may cause lift and prevent you from sliding into waves as the wave tries to lift the tail at entry to the wave. Again, I suggest you look at what the big guys are doing. - good luck.
Ok, I think I’m going to flatten the front all the way back to the tail where I will take the double down to a small V. Any suggestions where the V should stop and start. Oh the board is 17’’ 12 inches up from tail. And just under 23” in the middle. I went wide spot dead center.