I’m thinking about shaping a little tiny short biscuit-ish (ish!) board… 5’6-5’9, not certain yet. I’m attaching a pdf of my AKU file of what I’ve been playing with.
I’ve been considering something quite wide 20 1/2 - 21 maybe, thick but with enough taper in the foil towards the tail to still let the tail sink in and dig deep in turns etc… Quad…
I’m curious about placing double bumps and wings; thinking of the extra overall width and wanting to drop it down towards the tail for easier rail to rail. I already have a full on fish, I want this to surf more like a shortboard…
My outline’s double bump placement is aimed at lining the back two fins up with the inside of the aftmost bump. The front two fins would end up with the foremost bump somewhere near their centers… does that make sense? I’ve tried sifting through the archives for a few days when I’ve had the chances to but I haven’t come up with too much conclusive info. If someone knows a good thread that I’ve missed, please by all means direct me there! Otherwise; what do you all think?
Oh also curious about the rocker; not very much at 4 1/4 nose and 2 1/4 tail but it almost seems like more than the CI biscuits… maybe I’m just trippin’…
Not too long ago there was a thread… “the truth about wings (and bumps).” Read that, and you see there’s no “conclusive” answer about why or how they work. But… one thing that seems true today is that functional bumps (not just those little ones you see on boards just to make them look cool) at the center of the fin are not as common as at the trailing or leading edges.
My theory is that it makes most sense to put them at the trailing edges, so turbulence or cavitation coming off the trailing edge of the fin is released as soon as possible. When designing wings and bumps in relation to fin placement, I see wings and bumps as release points. They also help straighten the outline ahead of the wing/bump, while letting you quickly pull down the tail width behind them, as you mentioned. As for these features at the leading edge of the fins, usually you see a more pronounced hip in that area than a wing or bump these days. Putting a wing there usually puts the release point right under your back foot, so you have to move your foot to get ahead of or behind it, which seems a little awkward to me. I’d prefer it behind my back foot, and think of it in terms of release and planing surface reduction.
Some people hate wings. I like them, and think they’re really functional if designed to work with a few other design features, particularly with quads… like any tail kick you want to add, how much edge you have in that area, how you run your concave(s), etc.
The Biscuits use a retro-fish rocker. I measured a 5-6 that had 3.25" in the nose and 1.5" in the tail. I built a variant with a little different tail and deck layout but with that rocker and it works great IF you’re accustomed to flat rockers. That outline at 5-6 has about a 16" tail @ 12, and they set their (thruster) fin cluster in a little from the rail - the board still turns fine when surfed in the conditions it was designed for.
The rocker you’re considering is more similar to a …Lost Rocket. Lots of tail rocker relative to that length and template. Those boards are more about top-to-bottom surfing and snappier turns. Personally, I probably wouldn’t favor a quad in that length with that tail rocker but different strokes.
Personally, I like quads better for the Biscuit-type boards and the kinds of waves they’re designed for. I don’t see anything wrong with just leaving the template alone - no wings. A 16" tail width is not at all excessive for a quad pod. You just have to be a little careful with fin templates.
BTW, a 5-6 Biscuit with CIs stock foil and deck layout is good for about 38 liters on AKUshaper - that’s a lot of volume. The variant I built for my son at 5-6 floats him fine at 195# - it’s almost too much, but that’s probably because I squared the deck more to add a little extra volume. Next time for him I’d probably go back to the stock deck and foil. That board paddles a lot better for him than the 6-3 x 2.5 performance thruster I did for him last year.
My youngest son weighs 130# and I’m doing another one for him at 5-2 x 2.5 with a quad, and that’s probably more length than he actually needs for float/paddle. Just a little FYI for you for your volume considerations. Machado weighs ~140 and he surfs a 5-2.
I like clean no-wing outlines on boards like that. No real reason to shorten the rail line on tiny boards. But everybody's different, and if you want to do wings/bumps, get after it!
I'd suggest getting off the Aku, draw up a ''starter'' outline on the blank. Mark your fin placement and then decide your bump placement based on how the bumps interact with the fins. Adjust bump and fin placement accordingly if needed. CAD is great, but sometimes you've got to sight down the thing and visualize flows. That's hard to do on a screen.
Hey thanks guys for all the info… I’m psyched on taking it all in, and on having that lead on the bumps and wings thread. Sometimes the good ones just slip by in my searches… other times they land right in your lap…
That makes sense about hips rather than wings in front of the trailing edges of fins if they have to be there. I should quantify this whole question by mentioning that I’ve never surfed a board with wings at all before, so part of the reason I wanted to put some on this board was to just try it and see how it goes and how they feel. Maybe a hip, THEN a wing…
I’m fine with flat rocker, I’ll drop it a bit but maybe keep a touch more than the standard CI Biscuit rocker just for a bit of extra looseness. I think I will definitely drop down the tail rocker actually, especially if I keep the wings to narrow the tail, maybe add a little bit of extra vee instead.
Good reference to your son at 195; I’m 165 but surf in a 6/5/4 fullsuit so that adds maybe 15 pounds… I’ll maybe take that into consideration and drop down the length by a touch, perhaps a slightly slimming of the foil also.
Mike I totally agree with you about having to do it in the flesh (foam? lol) rather than in the digital… Mainly I am considering this to be a visual tool to play with it and to show you guys what I’m sort of thinking about… I think I’m going to trim out the wings and print off a clean outline, cut it down, shape it up and after I have foil in and the rails banded see about wings. Like you said, I think it’s going to be very helpful to have the fin measurements in place and be able to draw the lines visually… with pencils and straightedges and surforms. That’s where the real magic happens.
Thanks again for all the input… These were all great, informative replies!!! if anyone else has any other thoughts I’d be stoked, and I’ll maybe fire up some notices of progress as it goes. I won’t be starting this for a little while though. Got too much on the go the next couple weeks!
How do you reconcile your view with the Aipa Stinger design, where the wing is always ahead of the fins (by some margin, being about a third of the way up)?
I remember riding those stingers as a kid, but I’m an old guy now, so I really can’t remember what they felt like! Plus, there were a whole other set of design parameters going on back then, with much thicker foils and rails, bottoms were different, and certainly rocker was way different. But if you apply it to my theory, it puts the release point between your feet. That makes more sense to me than under your foot. I guess the concept was to have that “gas pedal” effect when you weight your front foot, but get the control and quick rail-to-rail of a much narrower board when you weight your back foot. Kind of splitting hairs here, but I see stingers are a rail line thing. Wings and bumps around the fins are tail things.
This is good, I like where it’s going. Obviously you can’t just hack a couple chunks out of the rail of a surfboard and stop thinking about it there… So I’m wondering about a couple extra details of how these things work together:
A. Fin to wing relationship: Trailing edge of fin lining up with the inside corner of the bump behind it. Makes sense as it aligns the fin with the effective rail that the water will be flowing towards…
B. Tail Kick to wing relationship: How do you feel is the best way to relate tail kick to wings? Should the kick’s placement be based on the location of the wing or vice versa?
C. Edge: I would sort of assume that with double bumps etc boards would tend to show quite a hard rail throughout the winged area, with maybe a more sudden transition from rounder rail to harder rail happening at the first (closest to nose) bump. Does this make sense? Is this what you find works, or are there more complex issues to be considered?
D. Concaves/Vee: I’m mainly thinking of using some vee, not so much about concave in the tail of this board in particular… should concaves in spiral vee tails also feed into the wings, in general? if so, what is the effect? more speed…? Looser?