What is the recommended angle of the foil (fuselage) compared with the underside of the board?

I suspect 0 degrees however I have heard numbers of 1 or 2 degrees.

Not zero...

You may find this thread helpful.
www.seabreeze.com.au/forums/Windsurfing/Foiling/Tail-kick-foil-rake?page=1

I'm not sure, whether it's identical for all type of foils.

For Phantom Race, Freerace and Freeride foils it's between:
2 degree (for light wind and flat water)
3 degree (strong wind, choppy conditions).

To reach this angle there are shims for the tuttle box.

Once flying how would this have any effect?
Surely you naturally adjust the board so as to fly level.

Well in my case +/- 10 degrees

Whether the board is out a couple of degrees shouldn't matter.

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AUS 808 said..
Once flying how would this have any effect?
Surely you naturally adjust the board so as to fly level.

Well in my case +/- 10 degrees

Whether the board is out a couple of degrees shouldn't matter.

The effects are huge. Theres 2 major points, 1 the power distribution over the feet, and 2 the part of the board which hits the water when you accidentally touch.

1. If you increase rake, so raise the nose you'll decrease power on the backfoot and increase power on the frontfoot, simply because you raise the front of the board, the front foot sits a little higher and therefore its easier to put preassure with it. Decreasing rake has the opposite effect.

2. If your rake is too little, you will catch water with the nose every time you accidentally touch, which can be disasterous. If you're off by too much it means every touch with the water will turn into a catapult.

Effects on getting in flight are so minor that to me they dont play a role when setting the rake.

I ride my Lok?foil with either 0.7 or 1.4 degrees worth of shims, although the fuselage is at 91 degrees to the mast, so I'm using an effective 1.7- 2.4 degrees depending on water state and windspeed and such.

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WhiteofHeart said..



1. If you increase rake, so raise the nose you'll decrease power on the backfoot and increase power on the frontfoot, simply because you raise the front of the board, the front foot sits a little higher and therefore its easier to put preassure with it. Decreasing rake has the opposite effect.

Sorry but I disagree, you naturally adjust your body to fly the foil level regardless of the board position.
We are talking such small increments you wouldn't even notice.
Then again I'm only starting out so don't have the actual experience, just my logic.

I've seen someone foiling at the local spot and the front of his board is heaps higher than the rear. The sailor appears comfortable but it looks weird to me.

What's the angle on dedicated foil boards ?

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AUS 808 said..

Sorry but I disagree, you naturally adjust your body to fly the foil level regardless of the board position.
We are talking such small increments you wouldn't even notice.
Then again I'm only starting out so don't have the actual experience, just my logic.

So... just a suggestion: listen to the guy who has heaps. I used to think the same thing when I started out.

Lokefoil video. Closed captions in English. And, yes, it makes a difference when you touch down at 25 kts. (I'm assuming because I don't go that fast and it makes a hell of a difference at 20) And go back and reread the Glissattitude article as they describe it as well if WofH's comments weren't sufficient.

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col5555 said..
What's the angle on dedicated foil boards ?

The angle is baked in by the foil maker if you aren't shimming. Easiest way to see this is in foils that have some sort of base plate such as SS, Loke, Starboard alu, AFS, etc. As t36 mentioned, I've read elsewhere that the top level are tuning it to both wind range and whether doing upwind/downwind or reaching/slalom.

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Paducah said..

AUS 808 said..

Sorry but I disagree, you naturally adjust your body to fly the foil level regardless of the board position.
We are talking such small increments you wouldn't even notice.
Then again I'm only starting out so don't have the actual experience, just my logic.

So... just a suggestion: listen to the guy who has heaps. I used to think the same thing when I started out.

Lokefoil video. Closed captions in English. And, yes, it makes a difference when you touch down at 25 kts. (I'm assuming because I don't go that fast and it makes a hell of a difference at 20) And go back and reread the Glissattitude article as they describe it as well if WofH's comments weren't sufficient.

col5555 said..
What's the angle on dedicated foil boards ?

The angle is baked in by the foil maker if you aren't shimming. Easiest way to see this is in foils that have some sort of base plate such as SS, Loke, Starboard alu, AFS, etc. As t36 mentioned, I've read elsewhere that the top level are tuning it to both wind range and whether doing upwind/downwind or reaching/slalom.

He confirmed everything I was thinking.
1 degree difference on touchdowns is high end race stuff, most riders angle of entry on a touchdown would be more like 5 - 10 degrees no negligible.
With regards to foil shimming I am not going there at this point, just getting the basics sorted.

Watching this video it contradicts the shimming of the box method, see 2min 40 sec in.
This makes more sense regarding the foot pressure because of the mast length but then stuffs up the board angle, so then maybe you need to shim the box
In my case I can move the foil back or forth in the tracks.

Or you can just get the right foil to begin with, foil more, and gain experience.

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IndecentExposur said..
Or you can just get the right foil to begin with, foil more, and gain experience.

The question was:
"What is the recommended angle of the foil (fuselage) compared with the underside of the board?"

Why do you guys have to respond when you have nothing positive to give, are you just lonely?

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AUS 808 said..

IndecentExposur said..
Or you can just get the right foil to begin with, foil more, and gain experience.

The question was:
"What is the recommended angle of the foil (fuselage) compared with the underside of the board?"

Why do you guys have to respond when you have nothing positive to give, are you just lonely?

Wait... you mean I have to comprehend the words I'm reading? Yes, quarantine has me bored, and probably cross-eyed with boredom. You are correct mate, I need to get out and sail.

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WhiteofHeart said..

AUS 808 said..
Once flying how would this have any effect?
Surely you naturally adjust the board so as to fly level.

Well in my case +/- 10 degrees

Whether the board is out a couple of degrees shouldn't matter.

The effects are huge. Theres 2 major points, 1 the power distribution over the feet, and 2 the part of the board which hits the water when you accidentally touch.

1. If you increase rake, so raise the nose you'll decrease power on the backfoot and increase power on the frontfoot, simply because you raise the front of the board, the front foot sits a little higher and therefore its easier to put preassure with it. Decreasing rake has the opposite effect.

2. If your rake is too little, you will catch water with the nose every time you accidentally touch, which can be disasterous. If you're off by too much it means every touch with the water will turn into a catapult.

Effects on getting in flight are so minor that to me they dont play a role when setting the rake.

I ride my Lok?foil with either 0.7 or 1.4 degrees worth of shims, although the fuselage is at 91 degrees to the mast, so I'm using an effective 1.7- 2.4 degrees depending on water state and windspeed and such.

Hi,

I also have a Loke Foil.
How do you rake the mast? What shims do you use?
Could you please send a photo?

Thanks!

Expensive version: www.phantom-windsurfing.com/goybox/p/goybox
Still sort of expensive version: marseille.glissattitude.com/windfoil/u37872s1-divers-cales-de-reglage-rake-divers-2019.html
Not quite as expensive: www.free-ride-addicted.fr/e-boutique/cales-de-rake-3/

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Paducah said..
Expensive version: www.phantom-windsurfing.com/goybox/p/goybox
Still sort of expensive version: marseille.glissattitude.com/windfoil/u37872s1-divers-cales-de-reglage-rake-divers-2019.html
Not quite as expensive: www.free-ride-addicted.fr/e-boutique/cales-de-rake-3/

Here's a picture from one of the above web sites.

So, how does this work again?
Looks like it just adjusts the height in the box.
Can't change the angle if it fits properly in the box.

Most of the top end race foils these days have a flat top on the tuttle head rather than an angle like a formula fin or the early ones. This is so the top of the tuttle head fits flush against the top of the foil box, it is way way stronger and the current gen foil fin boxes are designed with this in mind; they are flat at the top not angled like in your pic. The 'wedge' locking method such as originally intended with the deep tuttle box is not designed for the huge vertical loads the foil puts on the box, this leads to big problems keeping the foil angle consistent and a lot of times will split the box end to end. Back in the early days of race foils before there were all sorts of methods around this like wedges, filling the top of the boxes with epoxy/packers etc that those of us pushing the perfomance experimented with. With the latest boxes and foils it's no longer an issue. Some of the current gen race foils do still have the angled top but come with packers (aka phantom) so you can adjust the angle, this still means that effectively the foil is flush with the top of the box, the front is hard up and you put a packer under the rear end to adjust the angle; it is still hard against the top with the packer.

Now you're right, highly specific anlge adjustment is a race thing but this is what the original question is about. Initially thinking about it it would be easy to conclude that 0 degrees or even -2 degrees (main foil closer to the board than the stabiliser) would be a good angle as this should make it 'easier to fly'. In reality is doesn't make that much difference (race foil boards have huge rear cutouts to aid foil angle manipulation when pumping) and as WoH says when you're in the air or during touch downs the effect of this can be catastrophic.

You actually want it the other way, I run about +2 degrees on a starboard race setup, on average. There are two main reason for this, once again as WoH mentioned, touch downs, but the other big one is upwind aero. You think about it, upwind on a race foil in 15kts, you're doing 17-20kts depending on your mode, that's like going into a 35kt headwind, aero trim makes a massive difference. If you have your foil and hence board angle trimmed wrong, the aero losses and overall negative effect (think downforce on the nose from windage) can be huge and just make it a pain to sail. This might all sound like BS but trust me at the top of the fleet marginal gains and attention to details like this make all the difference.

I should also just clarify that as you and the Delta video mention we are changing the relative flight angle of the board to the water. This is not about CoE adjustment or anything like that as we have many other options for that with race setup, it's purely for ease of handling at the edge of control (high speed touch downs) and the aerodynamic gains when racing.

G'day,

for me it makes a big difference in flight, which angle the foil has. If the nose is too low, every gust the nose pitches down. Even with my mast foot being at the rear and the boom pretty high. After I made a shim for the Tuttle-head, I felt a big difference, as it is more neutral in gusts (unless they are pretty strong).

I can feel the difference between 0.0 and 0.7 degrees, 0.7 makes it harder to get my Goya Bolt planing in 8-10 knots, need to plane before getting up in light winds on a non foil board with a relatively narrow/ thin tail.

I think Sandman has it right. Once you are in the air, the angle of the board is less important than when it is still on the water. Of course, yes, this inflight angle is an arguable point, as made above.

When it is still on the water, the board bottom angle against the water pretty much determines what angle of attack is going on beneath by the wing. If the wing angle is too much negative, you have to really haul it into the air. If the angle is just right (probably a little bit positive), the wing angle of attack is already good, and you need only get enough speed to initiate flight.

However, don't get me started on shims (again). If they introduce point loads in the finbox, you are asking for trouble. Nuff said.

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segler said..
However, don't get me started on shims (again). If they introduce point loads in the finbox, you are asking for trouble. Nuff said.

Shims seem to be a fact of life for racers and those doing R&D. Be hard to avoid point loads anyway when bending moments are being resisted by fairly inflexible components mated without great precision in the initial manufacture. If you use rubber shims the loads may in fact be spread more than before?

The foil lifts about 200 mm ahead of the box, the box is about 100 mm long, fore and aft - about 2 to 1 load increase to be resisted by the rear bolt (or corners of the box if the fit is perfect).

The biggest box-splitting load is for racers on a 90 cm wide board is sideways, a 450 mm lever arm on a fin box only 65mm deep!, A 7 to 1 magnification of vertical forces when pumping from out on the rail!

But it shouldn't be hard to economically manufacture a tuttle box that will take the strain no matter where the forces take up. Getting it glued into the board is probably where cost vs quality issues are tested.

If the angle shims were doubled--one in front and another one upside down in back--it would be a way to continue to spread the load over the entire length of the front and back rounded tapers. No point loads this way.

I see, however, discussions about using only single shims. Maybe with the later generation of super-beefy deep tuttle finboxes, point loads are not a problem. Hope so for all those out there using shims.

Shims are, however, bad engineering. Fully seated front and back rounded tapers are good engineering. With the lifting wing located 200-300mm in front of the foil mast, the rocking cantilevering forces are massive. We rely on the front and back rounded tapers to carry those forces. Not a good idea to point load those tapers. Good idea to spread the loads top to bottom.

All of this will become moot as the industry goes hard over into dual track mounts for everything. Angle shimming with big tapered plastic rectangles that cover the entire bottom area of the plate will be easy.

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Ian K said..
But it shouldn't be hard to economically manufacture a tuttle box that will take the strain no matter where the forces take up. Getting it glued into the board is probably where cost vs quality issues are tested.

From what I've seen, you can wrap enough cf and s-glass to handle the loads. If you watch the Patrik Air Inside video, he gives it plenty of "point loading".. Santa Cruz mountain bikes had a video where they bashed the crap out of their carbon frames. And in the US, we have composite baseball bats (which actually worked too well).

The challenge, as you mention, is to keep the whole affair from ripping out of the board and that takes lots of not so cheap PVC foam. Most of the failures we saw in the early days was the whole box ripping out of the board, iirc.

Seatex is located on Lake Garda. I'm sure plenty of their boxes are in high stress uses.

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segler said..
If the angle shims were doubled--one in front and another one upside down in back--it would be a way to continue to spread the load over the entire length of the front and back rounded tapers. No point loads this way.

I see, however, discussions about using only single shims. Maybe with the later generation of super-beefy deep tuttle finboxes, point loads are not a problem. Hope so for all those out there using shims.

Shims are, however, bad engineering. Fully seated front and back rounded tapers are good engineering. With the lifting wing located 200-300mm in front of the foil mast, the rocking cantilevering forces are massive. We rely on the front and back rounded tapers to carry those forces. Not a good idea to point load those tapers. Good idea to spread the loads top to bottom.

All of this will become moot as the industry goes hard over into dual track mounts for everything. Angle shimming with big tapered plastic rectangles that cover the entire bottom area of the plate will be easy.

Agree!! (For once in a while ;) no harm inteded) i use shims regardless, because as far as I know there is no better way currently in the case of dt boxes.

We all know already about point loads destroying carbon. Just nick a sail mast and watch it break when loaded. We have all done this, especially with monster race sails with really long SDM masts (520, 550, 580).

Aluminum is much more tolerant of point loads, but then our finboxes are not made of aluminum.

Yes, the new super-beefy DT finboxes are much stronger than before. They can perhaps tolerate point loads, but I never plan to test this. I will always fully seat the front and back rounded tapers and leave it at that. If the rake angle is wrong, I will get a new foil or new board to correct it. Don't defeat the design by point loading it.

As was said above, the trick now is to make sure the whole box stays in place. To that end, North Pacific, for one, connects long stringers to the DT finbox to add a lot of rocking cantilever strength.

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All of this will become moot as the industry goes hard over into dual track mounts for everything. Angle shimming with big tapered plastic rectangles that cover the entire bottom area of the plate will be easy.

I wonder if racing equipment will ever go to dual track. It has too much drag compared to DT. And when I say too much drag, I am talking about drag that proficient sailors (not me) can notice. You know that in racing even minimal changes can have big impact. If I were a pro racer or even a very competitive weekend warrior racer, I would not mind to risk a broken DT foilbox if that would give me any advantage performance wise compared to a more bulletproof twin tracks.

Also, windsurfing companies need to win races in order to show off and tell us how good their products are. I have never seen an ad saying: we haven't win any race but our boards break less than the ones winning all the races.
BTW, I would not mind to have double track system on my iqfoil if it made it more secure!

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segler said..
We all know already about point loads destroying carbon. Just nick a sail mast and watch it break when loaded.

The proper way, and Seatex does this if you watch the video , is to use other materials than just carbon. Carbon is stiff, carbon is light but carbon sucks for impact resistance. There's a way to make a composite box that will withstand winfoil loads. They make composite baseball bats after all. Carbon breaks because of its failure mode - when one strand of fabric is broken, it creates a stress riser and propagates. Wrap that same cf mast with innegra, texilium, s-glass, etc and you have a much more robust mast.

Windsurfers think CF is some magic beans material when, a lot of times, it's the wrong material for the job.



How adding a layer of cf doesn't always do what you think it does for strength



Witchcraft boards test (fun begins around 1:19) Yes, there are dents but those are probably only a couple of layers of fabric with just medium density PVC foam underneath.



Santa Cruz mountain bikes point loading a frame against concrete (skip to around 5:10)

Would definetly be intested in a Witchcraft board if they made one with a foil DT box!

I will let everyone know how my Goya foil ready DT box fairs with a shim. On close inspection it does appear the top of the box is solid carbon fiber based on what I can see in the screw holes. Can not rule out a few layers of glass, but it looks like solid carbon fiber.

Yes, for impact resistance, nothing beats kevlar, followed by glass, then carbon a distant third.

However, for bend and tensile, carbon is way up there compared to glass and kevlar.