hi guys i just shaped my 5,6 rob’s go fish replica but i’m having problem understanding fin box installation.so the problem is since futures fin box should be installed flat and in the fins area i shaped a double concave contours it would be end resulting in a different deepness as i get closer to the rail because it is higher. so the box is leveled with the foam in the inside but quite deep on the outside and the thing is pretty noticeable . am i missing someting?in attachment i tried to drew on a paper the problem to be more clear about it( view from the front,tail side) , hope it can help. thanks in advance!!
You’re correct with your drawing that the inside of the box will be level with the foam and the outside a bit sunken in the foam but the difference isn’t much over the width of the box. By the time you put your patches over the boxes, then bottom lam and hot coat it’ll all smooth out.
I’ve done a bunch of double concaves and haven’t had a problem but the concaves aren’t that deep. I do have a Roberts Mutant though with a MASSIVE double concave and Future boxes and it’s fine.
Did you rout the boxes yet, how deep are your concaves?
the plan is to copy the outline of the go fish and bottom contours of the seaside by rob machado…since the seaside have pretty deep concaves i ended up with 0,5 mm single concave to 0,4 double slightly decreasing to 0,3 mm… i routed only the first “channel”… still have to shape the deepest part of the box because just in case if i was doing it wrong i still could solve by raising the lower part but if you say that it is right …still seems to me a bit weird to see space between the foam and the box though. if i look at some photos online with similar concaves it seems all leveled.
Yeah it does seem weird to see that gap on one side of the box but it’s the only way to keep your fin box level so the cant on your fins are correct. If you put the boxes in even with your contours you’ll lose fin cant and your fins will be more vertical. The Futures installation kit comes with EVA foam shims just for this purpose to get your boxes level depending on your bottom contours.
There’s tons of boards with Futures and all sorts of crazy bottom contours, I bet if you look close you’ll see those little differeces between the foam and box. I’ve had boxes that were sunk way too deep because my router was set incorrectly and they’re fine. Whatever gap you have will be filled with resin, glass and eventually hot coat.
Think about the curve of the rocker in the tail where the box is so there’s a little gap there too, I drove myself crazy thinking about this stuff also haha when I started using Futures but it works out fine.
yeah i was thinking about how the rocker will create the same issue too! so i guess it is all fine… tomorrow i will finish it all… btw what is this EVA foam that keep it all level?
The Futures installation kit I purchased a loooong time ago came with EVA strips of foam. It’s basically the foam that’s used on soft tops, the original kit from Futures had various pieces that were 1/16" to 1/8" scraps of this foam to use as shims to level the router jig.
got it…i guess it solve the curve of the rocker only…anyway thanks for support!!
I have a similar question. How would you set the future box in a tail with channels (such as the “Tomo Style” boards) if you want to line up the inside face of the fin with the channel line? It seems like you would sand through the inside flange of the box or if you set it deep enough to flush with the channel, then the outside of the box ( and fin) would be too deep.