Hydrofoil Shimming Explained: Baseplate and Stabiliser Shimming Gide

[@Bluemeaneyes20]

Excellent video and explanation!

[@hydrofoilacademy]

Glad you liked it!

[@Giovanni.Tedeschini]

Thank you for this video. Here in Italy we use the word "rake" to identify the angle between the board and the mast, basically we shim the plate to get a different rake.

[@hydrofoilacademy]

Thanks for sharing!

[@smytharmstrong8543]

Thanks very much or this video -- instructional, educational and entertaining. For paddle ups and super low wind winging I will put the thick part of the shim at back of the mast. I also have a large HA foil that rides nose down so I'll try the opposite and put the thick part of the shim at the front and see if the board rides more level. Great videos! Keep them coming.

[@hydrofoilacademy]

Super glad you like them. Definitely play around with this, it makes a huge difference.

[@blooskyy7]

Great explanation, thanks for sharing

[@hydrofoilacademy]

Glad it was helpful!

[@tsipporah87]

Thank you for the video. Been playing around a lot with the tail shimming on the Armstrong APF because my track box on the board is too far back for the pump foil. Recently got a 3D printed mast shim, can’t wait to try it out.

[@hydrofoilacademy]

That's exactly where a shim can help! I've got an Armstrong APF on the way. Can't wait to try it.

[@MatsBohlinsson]

Really good!

[@hydrofoilacademy]

Thank you! Cheers!

[@joemiller8029]

this video was incredibly helpful, thanks!

[@hydrofoilacademy]

Glad it was helpful!

[@MrHUGOLADEIRA]

AMAZING explanation, thank you! subscribed 🤝

[@hydrofoilacademy]

Thanks for the sub!

[@karchexdziadkowo1866]

good thing I found your video. I only use it for wingfoil. when there is less wind and I would have to have a bigger front wing. what to change to make the set with a smaller front wing work like with a bigger one. easier to lift. Greetings from Polan

[@hydrofoilacademy]

If you shim the tail for more angle of incidence that will give more lift for the same size. The drawback will be it won’t be as efficient and it will be slower (more drag).

[@karchexdziadkowo1866]

and if I put plates under the rear screws (positive angle), won't it make lifting easier in weaker winds? better option?? I measured the angles. the foil and the board are parallel and then the nose of the board clearly goes up. Thanks

[@cartender9200]

Great Video ! I still dont understand what is the difference between shimming and moving mast. If for example my nose wants to go down , why shim it positive and not move mast forward? Thank you in advance!

[@hydrofoilacademy]

Shimming has an impact on lift and drag. Moving the mast does not. If you want to make the gear more efficient or slow it down and produce more lift, this is when you would shim. Most people shim negatively, to take drag away and make the foil faster. I would move the mast forward to compensate for the reduced front foot pressure in this case. Hope that helps.

[@cartender9200]

@@hydrofoilacademy Thank you very much :)

[@brantfredrickson4766]

Thank you for your video. I'm a windfoiler and use negative 3.5 degrees of board shim to help me not catiplut on touchdowns. Its interesting to see you do the opposite in your disipline. There is a local kite foiler who does the same as you and rides in the nose down position at full throttle.

[@hydrofoilacademy]

Yes, in full send, putting a shim at the front will make the ride more comfortable. Glad you are enjoying the videos.

[@ericfernand]

Could you comment on shimming for flat water pop up ease? More or less AOI?

[@hydrofoilacademy]

That’s exactly why I would place a shim at the rear of the baseplate. Make the flat water paddle up as easy as possible

[@ericfernand]

@@hydrofoilacademy Understood that, makes a lot of sense, sorry I was referring to stabilizer shimming*** How would you stab shim to get easy takeoff? less shim would make sense because less drag overall? Thanks

[@kountchev1]

thanks for sharing! does that mean one could get away with a smaller front wing for given wind strength? which mast plate shims (brandwise) are you using? it'd be fun to test the your revelations. KEEP THEM coming!! thanxx Jordan

[@hydrofoilacademy]

Hi Jordan, Thanks for the kind words! Yes, thats exactly why I shim. So I can use a smaller foil than I would need otherwise. I had a friend 3D print them for me but I hear the Armstrong ones are really good. For a super cheap option, go to your local hardware store and get some washers. Glue them together and place them under the back bolts to the mast. It doesn’t look as good but it works just fine. I did this for a year or so before I got my fancy ones.

[@kountchev1]

@@hydrofoilacademy thanx! as this is new territory for me: you mean shim the entire mast and not bother for the stab only?

[@Louardoul]

Amazing video. I thought that the front wing was always lifting the foil, and I discover that the front wing causes the nose to pitch down. But I have a question: when the speed increases, the lift force becomes greater, whereas the weight of the front wing doesn't change. Does it accelerate the pitching effect, or the reverse? When I'm on my foil, the faster I ride, the more pressure I feel on my front foot: why? Is it due to the stabilizer or to the front Wing?

[@hydrofoilacademy]

Good question! OK so you are correct, the weight is a constant, this never changes. As speed increases, the lift (and drag) also increases. Both the stabiliser AND the front wing produce more lift. The pitching down force (only the flow off the rear of the foil - the CofG does not change) also increases but not at the same magnitude. The force you are feeling at higher speeds is the lift from both the front foil and the tail.

[@colinernst820]

If you shim the stabilizer with a positive shim will it help the board fly more level from the nose up position it currently flies in or does that have to be done with a base plate shim? Thanks for the video it is very educational. I appreciate the work.

[@hydrofoilacademy]

Thanks for the kind words! Shimming the tail (positively) will give more pitch up at faster speeds (and more drag). Shimming the mast will change the level of the board in relation to the surface of the water when foiling at an equilibrium. I hope that makes sense.

[@TheSmarquez]

I just got a Cabrinha X1950 out of my foils, all my riding experience and boards have it mounted in the right position, getting up on foil and massive amounts of speed, for the life of me I could not understand why I keep losing altitude, I have to work some much to keep the board from touching down, it will immediately recover if I weight back and pitch the board up, but on all other foils/boards I don’t have to do this. Also it’s a bigger foil than some of my others, at lower speeds that other foils can glide, this one needs more complete pitch resulting in a stall. I feel after watching this video I need to shim the stabilizer to increase the angle of incidence for more static lift. Does this sound like the solution @hydrofoilacademy

[@hydrofoilacademy]

It sounds like you need more stability in pitch, so either bigger stabliser, or shim the current one. You could also try moving the mast forward too, but not at the same time. Change one thing and see how that goes.

[@Gilloup]

Why chosing tail instead of plate shimming, or the way around ?

[@hydrofoilacademy]

With the tail you are introducing less drag by shimming. If you shim the base the drag of the whole lots goes up.

[@Gilloup]

@@hydrofoilacademy Thanks ! Yep I had understood that thus I reframe my question. Both ways can provide more riding lift, or less, correct ? Why using one way instead of the other if you aim at tuning the lift when riding (not when taking off) ? You say the plate shim slows riding, do you then conclude that the tail shim is always to be prefered ? One of my planes lifts too much and has a removable tail.

[@simonm7776]

Very good

[@hydrofoilacademy]

Thank you mate!

[@michaelkihn8311]

I think we shouldn't speak of "angle of incidence" when describing "base plate shimming" since the "angle of incidence" describes the relation between the stabilizer's chord and the fuselage! This might help avoiding some confusion, since increasing the angle of incidence in the rearwing means tilting DOWN the rearwing in relation to the fuselage wheras increasing the angle of incidence of the complete foil section means tilting UP the foil section in relation to the board? Well, I might be overthinking haha Great video!

[@hydrofoilacademy]

Angle of incidence is always referenced to the fuselage. Hope that helps.

[@franpinyol8500]

The plane toy is illustrative, but not a valid scientific proof point. Without the rear wings, the plane nose dives because of overweight in the front, not because of the no-stab effect. You are right about the angle of attack of the plane is always pushing up (positive angle, wing is slightly facing up) and the stab compensates it.

[@hydrofoilacademy]

Yes, that is my point. The forward C of G for the toy plane (very extreme in this case) is countered by the Stab's lift. Foils also have a forward C of G. It's not the angle of attack, its the angle of incidence that is at play. Angle of attack can be changed at any point using body weight.

[@franpinyol8500]

@@hydrofoilacademy thanks ! We love your lessons and youtube channel

[@Subscribe2Glide]

Try to dockstart with no rear wing shim, this will be a better illustration

[@defenderoftheadverb]

You have a bad habit of speaking loudly and then softly. It makes you hard to follow.

[@hydrofoilacademy]

Sorry!

[@wingfoil.lessons]

Just ridiculous comment

[@Foil4life]

I didn't notice that at all... Not sure if it's accurate...​@@hydrofoilacademy