Displacement vs planing regime for board shape efficiency in low wind winging

Hi Guys.

Coarsly simplified, in a nutshell:
-in low, displacement speeds, long and slender and fair with no edges is key to reduce viscous and wave drag to be more efficient through the water…(compare low wind region sailboats)
-in higher, planing speeds flat and wide with hard edges is key to plane efficiently on top of the water (sufficient forward thrust needed to get over bow wave…compare e.g. motorboats (sprayrails) or windsurf formula boards…)

Now thinking of pumping onto foil with a wing…at first you are obviously in displacement mode and usually get on foil before actually achieving typical planing speeds. BUT. As you are pumping the board (and foil) you are increasing the dynamic pressure on the bottom significantly, therefore getting to a (semi-)planing mode at lower speeds than the normal planing speed of your board. Hence the need for sharp release edges at least at the tail (transom) and aft rails of the board…
Also, you want a rocker and lengthwise volume distribution to allow to rock the board enough in pitch to activate the foil. For a given volume a transverse cylinder (log) would be the least resistance, a long flat plate laying longitudinally the most. Hence rocker and narrower nose and tail/cutouts/step tail etc…
The magic question seems to be to find the right balance between the three contradicting shape necessities, also taking into account pitch and roll balance and rider controllability…

In a perfect world i’d still study yacht design and have access to a towing tank and time to test different models and shed some light on some of my ideas and then use my snowboard building lab to build them…
In reality for the moment i’ll have to confine myself to trying the few to me available boards and relying on feels just like any other of us…

But at least maybe someone has tried a lot of (weird) shapes and also some of those barracuda shapes or similar for winging though and has some ideas on how they perform there?


Ps. Thanks Eric, this forum is a great idea…

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Fanatic wing board bottom shape, combined with narrowness, is the most efficient hull shape I found. My custom is 5’2 by 20" 70L and it gets going with almost no pull from the wing. Flying with 1000sqcm foils in 8kts became a common occurence.
Have not compared with barracuda shape, but it would have to be compared with similar length right?


interesting…unfortunately i cannot open insta at the moment, my browser security settings somehow block it…anyway, 20’’ is rather narrow, is it still stable enough to slog/how much you weigh?

Yeah in theory you’d only change one variable at a time, so same dims and only the shape would be different…unless you shape them yourself it’s hard to get that, also taking into account your own progress in skills…and confirmation bias will kick in anyway, so some variation can still be tried to be interpreted nonetheless;)

i just got an ak phazer 5’3 x 24’’ x 66l, will be interesting to compare it to the appleslice v2 4’11 x 24’’ x 78l and the sunova aviator 4’10 x 23.5 x 60l i got…i feel that around your bodyweight (i’m 73kg) in volume smaller changes in volume have a bigger effect comparatively than when going way below or way above…trying to hone in on that one, hoping the added length will help with efficiency…the sunova is too small (and heavy) for the very variable supergusty conditions we have on our swiss lakes and the appletree feels a quite a bit too boaty…hoping for wind next week, we’ll see

I just bought a used Kalama custom 7’6"x20"x 4 3/4". Dave made this board for himself as a Gorge prone DW board a couple years ago. It has a lot of Barracuda attributes. It is the most beautiful board I have ever touched. Anyway, I took it for a lightwind wing the other day and it was quite eye opening. The wind was 5-12mph. Using a 5m wing, I was able to get up on foil very easily in far less wind than ever. The board only weighs around 6lbs, so once up, it didn’t bother me at all having a board thats 2.5’ longer than I am used to. A lot of the board is behind me anyway. I have been wanting to try a long skinny kinds for years. It seems to me that a good amount of my sessions are in light wind with my Axis 1099. I am stoked to have this light wind weapon to enable me to go in almost nothing. I am interested to see if I can get away from the 5M wing and go smaller. Thanks Dave for being a forward thinker and amazing craftsman. I feel so lucky to have stumbled upon this. Thanks Bruce for selling it to me.


That’s awesome feedback, the light wind future looks bright! Nice looking board, you must be so stoked

80kgs. I take off on the board straight away like on sinkers (no knee phase), so stability is never a problem, the limiting factor is to pack enough volume in the board without being too thick, otherwise I would go 15 inch wide. I think width of the board is as critical as length, just like downwind boards as we see happening at the moment. I would not go longer than 5’2 though because it gets in the way in the pocket of the wave.

little update, sorry am very busy at the moment…

so doing some very scientifically objectivised testing - basically i went winging haha - i tried the phazer v3 5’3 66l in low and medium winds… i absolutely love it…longer is faster i guess…it feels superefficient through the water compared to the other boards i had, sold the appleslice v2 76l straightaway…as long as there are no waves slowing you down, you can really accellerate it pumping the wind even when you feel very underpowered…also feels way more stable to slog than others of similar volume…highly impressed…

on a sidenote…i also tried the new longer fuse from uni with the kd boomerang tail…he always claimed this setup would lower the low end of the front foil…and i think he might be right there, my technique will probably need further improvements to really hone in on this, but felt i could go from vyper 190 down to the the 170 (which i kindly got as a present from them for waiting for the 190 so long)…

on another sidenote, i also finally tried the north nova lightwind 7m (the lightwind version) i got a while ago and i can highly reccommend as well, very grunty, easy to pump, span feels cmfortably short (especially compared o the f-one 7m cwc), nice hard handles…and surprisingly you really don’t feel the weight at all…it is quite a bit heavier than the f-one but so balanced you don’t feel it…very interesting…wouldn’t have thought…and i really put an emphasis on light gear normally, my brm wings are very light comparatively…

so the search for my perfect setup slows down, i guess i am finally getting closer, after gving in to my foilbrain and stretching my cc too often…i’ll try to contain myself and keep to this setup for a while and work more on technique …maybe the progression 170 though haha…

Hi @andiabel !
Good topic placed! I’ve had several boards and been testing some of the designs that the innovators in the industry show and how it feels for me.
About the target of getting up on really light winds, for me it’s all come down to the downwind sup foil boards, I’ve designed and my shaper build one that’s 6’2"x22" with around 88 lts (I’m only 70), I introduced some tail and nose concepts from the barracuda but didn’t went as long as a barracuda, and it makes it an awesome light wind board, I can take it off on 8-10knots with only a 4mts wing and a FS1150 foil. What you mention about tails is true too, a bigger tail will help with low end A LOT!

In the last progression podcast with Dave Kalama, he mentioned something he learned about if water is entering thru a planning nose, it should be exiting thru a planning tail! Same applies for displacement, so, don’t mix both, what would you say about this? Since you started mentioning mixing hulls.

Have a good one!

Since you are familiar with the Appletree v2, have you seen the Appletree board that Dylan Wichmann has been winging on? It looks similar to the v2 shape, but the rails are softened quite a bit and it has a subtle keel feature at the tail. Kind of an interesting progression in shape with some Baracuda inspiration.

I also think that this discussion is pretty different depending on volume / weight. A sinker board needs features to bring the board to the surface under minimal power. The same features that build surface speed might actually impede with takeoff on a sinker.

<<UPDATE - Appletree released the Apple Skipper prone board which has the keel feature at the tail that I was referencing. Im almost positive they are testing this out on a wing board too. Pretty interesting design.>>

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I’m a beginner, getting around, starting to connect a couple turns, living in Central Texas, a fair amount of light wind days here. I am absolutely loving winging on my 7’0" Dagger. It just kisses off the water compared to my F-One ASC board; the taxi speed is must faster as well. Once on foil, I am enjoying the turnability of that board, I’ve got my Armstrong rig mounted in the front ⅓ of the track, it pumps great, I feel more connected to the foil than on my ASC for sure, swing weight doesn’t feel too crazy different for where I’m at experience-wise. If you’re looking for a light wind winging weapon, I’d really consider a downwind board.


Hi OmarFoilCol
sorry for not answering earlier.
Sounds good, you have some pics of that board?

What Dave mentioned in the podcast is the hull speed of a displacement hull, which is the maximum possible speed of a hull in displacement mode, basically depending on the wavelength of the attached bow-stern-wave (one wavelength with max amplitude at bow., lowest amplitude at stern). that’s why a longer, slender hull is faster in displacement mode.

What he meant with mixing is combining a full on displacement bow with a full on planing stern, which won’t work because the bow will prevent that it can rise above its wave.

But you can absolutely mix some design elements, say make a hull that is rather long and slender with some rather round parts of the sections but also add some chines and flatter bottom areas and rockers to still make it plane eventually but also be more efficient at low speeds than a full on planing hull.


yeah i saw that one…looks nice…it is still rather short, so they do not make use of the main speed creating element, which is length… so am rather sceptical if it will have enough of the desired speed enhancing effect for winging as at this length he weill need to rely on board pumping/planing effects as well… might work for prone…or they make a longer version…

That nose needing to match the tail is an interesting idea but I don’t think it is strictly true, sure canoes historically have followed that rule to good effect, and so have sail boats, but as soon as sailing started foiling, they dropped that for a variety of variations. Scow bows with very square chined sterns for mini transat boats. Americas cup another world even. I’d take that comment with a pinch of salt as not a strict rule but something to keep in mind?

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But a hand shaper from the 50’s came up with it so it must be true! The magic the hand shaping puts into the blank can’t be wrong!

of course, you are right. i neither meant it to sound as a rule nor that it wouldn’t allow for exceptions when you add foils or excessive sail power or waves… but i was rather just thinking about the slender displacement canoue trying to fully plane, which won’t really work. it might be forced into semiplane just as some sailboats with enough push of a wave, changing the attached wave in the process…but the scow mini’s are super wide so that helps with planing…and also have added a foil lifting the bow… i have a vernor mini simmons with kind of displacement elements up front and a wide tail in the back, but it is 22’’ wide so it does plane…

regarding the shape elements for sinker boards i do not think they change…what i mean is a longer board will be easier to set and keep the most efficient angle of attack to get to the surface as well as some width will help with creating enough lift to get there too and then help with release…i am 74kg and my 5’3 phazer will be easier to slog and get going than some shorter 75l boards…

I’ve been experimenting with a different hull shape that is a displacement hull but in gradients. I designed as an experimental downwind board, but now I sup and wing it all the time. I barely ride other wing boards at this point. But I just cruise and carve. No airs and I’m generally offshore playing in bumps. For me winging is about being on foil and just avoiding shockers. That board seems to do it. It’s the board in my latest sup clips.

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Interesting Erik. Unfortunately my browser doesn’t let me open instagram at the moment, some security settings problem… and i deleted the app long time ago;)…would you mind posting a pic here? what dims? you reckon it gets up earlier?

Also what software do you use for designing, Rhino?
I got a used microscribe digitizing pen a while ago and started scanning some boards as a reference point to design something myself…i suppose you ride without straps so the balance of the centre of buoyancy needing to coincide with the strap position is less of an issue?..but which is essential when using straps…