I am soon going to begin shaping my second board. It’s going to be a 5’10" x 21" x 2 5/8" twin fin, with a 15.5" nose, and 16" tail (12" tip to tip measurement). I just got my blank the other day. It is the US Blanks 6’2" C, with the nose rocker reduced by 1/2".
Here’s what I am wondering about. I understand that I should take as little foam as possible from the deck. It seems like this really limits the rockers that can be shaped from a given blank without ending up with very thick noses and tails? So all the thinning of the nose and tail has to come from the bottom of the board? My blank is listed as 2 7/8 inches thick, and I am shooting to yield a board which is 2 5/8" thick. I don’t have much foam to play around with, but I’ll still need to thin out the nose and tail. It seems like there is not going to be any way to do this without increasing my nose and tail rocker?
On my last attempt (also a 5’10" twin fin fish), I ended up with way to much rocker in the nose and tail. For that one, I started with a 6’10" fish blank (not by choice), and I think I may have templated it to close to the nose. I just really didn’t get the rocker and foil correct, and the way it rides really shows this…
For what it’s worth, I’m hoping to end up with about 3.5 inches of nose rocker, and about 1.5" or so of tail rocker.
My home made fish has a lot of thickness in the nose and tail. I would like to have reduced it, but it really is no big problem ( and im no good with a planer! ). Although, i didn’t really have to mess with the foil, as the majority of the thickness is under my chest, in front of centre, so maybe that’s why it isnt a big problem. Those rocker numbers seem really low, do you need to go that low on your rocker numbers??. Mine are something like 4.5’’ nose, and 2’’ tail, and i catch waves with the mal riders.
I’m no expert, only done 2 boards, but I think that getting the rocker, foil, thickness, etc. correct is WAY (x10) more important than making sure that you don’t take too much foam off of the deck. Also, keep in mind that you won’t be spending that much time on the nose or the tail of the board (although I do like to bridge the gap of the buttcrack on cutties on mine), so the density of the foam in those parts in not so much of a concern.
In retrospect, if there is one thing that I could change is to have thinned out the tail tips a bit more. When the shape was finished I thought I had made it too thin, because it was so flimsy (no stringer there), but after it was glassed, the tail seems a little bit to beefy.
I don’t HAVE TO go that low on my rocker numbers, but I’d like to. From all the reading I have done on this site, it seems like those numbers match up well with the kind fo fish I want to end up with. The last one I shaped had about 5" and 2" or so, and it feels like it’s pushing water when I paddle. The rocker and foil don’t flow that well on my first attempt, which I am sure has an affect along with shear amount of rocker.
I would mark out your template on the board, moving it around until you get close to the rocker you want. Not that it helps, but I’m planning on shaping a 5’10" fish with 4" of nose rocker and 1.75" of tail rocker, but with cutting your own EPS it’s easier to achieve this.
Even with the inconsistent density of a PU blank, you can still take thickness out of the nose from the deck. I mean, you probably won’t spend a lot of time stomping on the nose so if the foam isn’t as strong there it won’t matter. If you need to take thickness out of the deck in the tail area instead of from the bottom to meet your preferred rocker, just add a 4oz deck patch running 3/4 of the way up the board if you’re worried about the foam being too soft.
But since you want a 1/4" off the blank, skin it both sides, then adjust your rocker if necessary and then take down the thickness by planning the bottom.
Obproud- Did your blank also have the -1/2" nose rocker? Did you end up having to take a lot of foam from the deck, or did you take the thickness from the bottom (and thus increase the rocker)? What rocker numbers did you end up with when you were done?
Seems like an imposible thing to do, but try to picture these consepts;
the thickness measurement is at the center of the board on the stringer, and not at the nose itself. Therefore you dont want your nose thickness to be 2 5/8
If you cant get the rocker you want by thinning the nose from the deck by itself, you have to flatten the rocker elsewhere; on the bottom.
so heres my advice…dont skin top and bottom cause you may need that foam. start by templating at the base of your blank. Skin the top, especially up in the nose area till you get a thickness in the nose you want, then skin the bottom, going deeper in the midpoint of the board. This will flatten the rocker profile, while maintaining as much foam as posible. It helps if you have a clark planer, i dont and have never had to try this, but just visuallizing it seems like the best option.
If I want to make a thick low rockered board I go with longer blanks and cut them down properly. A benefit of this is allowing you to easily control the position of entry rocker. Here is a sketch of a thick low rockered board with thinned tips board I recently designed; rocker is 4N and 1.75T. The last one I made was a 6’2 that was cut from a 7’0R blank.
Well, I’ve been playing around on AKU shaper…When I line up my board with the blank, it definitely looks like I can get the rocker that I am looking for from it. I will have to take thickness from the deck on the nose and tail, but it doesn’t look like TOO much to me. Maybe I’ll just stick a stomp pad on the tail to help protect the less strong foam. I’ll try to get a graphic of the board and blank profiles together for you folks to check out, and rip to shreds. Haha.
My blank did have -1/2 rocker, but I wasn’t shooting for 3.5" nose rocker, more like 4" (the board I was trying to “copy” had about 4" of rocker.
I didn’t take much foam off of the deck, I used all hand tools (no power) and took most of the foam off of the bottom. I also put a pretty hefty concave in the center which decreased the centerline rocker (more than I should have, I think).
I don’t remember the final rocker numbers, but I will check later tonight after I get my shaping stuff back from my friend.
I don’t understand why you will have to take a lot (i.e. too much) foam off of the nose and tail deck to get a good rocker curve. I also think that with such a relatively big fish 3.5" of rocker might be too little. I would understand if the board was 4"-6" shorter, but 4" of rocker works really good on my board, it paddles well and is very fast.
I wouldn’t worry about thickness numbers too much. You’ll be able to feel that, whereas rocker is a fickle thing. With thickness if it feels good under your arm, you’re golden. Can’t say the same for rocker.
Also don’t worry too much about taking your foam off the deck-side tail and nose because you won’t stand there too much.
Just thought I’d post the template and foil/rocker that I am pretty happy with. Check it out, and please, rip it to shreds, I want to know how I can make it better.
Edit: The rails are still in progress, so don’t bother commenting on those, unless you really feel like it. Haha.