Foil rake shims

Pretty much all of the designs I've found had one or several things I didn't like from an engineering, customization, or ease-of-use standpoint. Therefore, I made my own from scratch, and also made a few custom ones for my friends. If anyone needs them, let me know, and I can print more.

As discussed in other topics, one of the key issues is that most of the shims are square and not triangle shaped. This creates point loads and sometimes uneven-inconsistent settings. See the photo from GlissAttitude below: when you rake the mast, the space between the top of the mast and foilbox becomes angled - triangular. The best case is such shims get deformed over time so you need carbon or steel ones, worst case is you don't shim at all, which can make the foil move (rotate) during sailing and will eventually crack the foilbox.

Therefore, I took the original Tuttle specifications and first drew a 3D model of the deep Tuttle fin head. I continued with the square foilbox and square IQ-foil mast to verify the fit and dimensions. This way, the shims can be precisely designed either designed by 0,25 mm or 0,25?, and finished with rounded-filleted top edges to sit nicely in the box.

After a few prototypes and feedback from IQ foil racers, the shims are now completed. I use mine with Starboard-flat mast and flat foilbox on a 1 m wide course-race board.

The more significant challenge was creating a special shim for masts that aren't flat on the top: such as Phantom or F4 Foils. Similar principle to the above, but with an extra built-in angle for the rake setting.

Also for a standard deep Tuttle foil that is completely angled (eg. Z-Foil), like old formula fins, that can be properly shimmed too.

I can print and send the shims if anyone would like to use them. One day I'd like to see the windfoil manufacturers provide the rake shims (or at least the print files) with the purchase of the gear, it would cost them next to nothing and make the surfer's life much easier.

Thank you :) I will print more, as I've gotten a few requests already, so it's not a problem to add one set, just let me know what would you like (easiest over private messages).

For the standard deep tuttle combo it can sometimes depend on the foil box and foil mast heights, but usually the triangular ones work well in my experience (have used NP-F4 2018 carbon foil in standard deep tuttle box).

I'm not sure I fully understand the part around the matching shim for the deck area, did you mean something like this? Those are for the plate mounted foils, pic source is AP 3D custom:

OK, those look good for the tops. Now, what about shims for the front and back rounded tapers to spread the loads there, too?

If you only shim the tops, the tapers become point-loaded. Recipe for failure.

Select to expand quote

segler said..
OK, those look good for the tops. Now, what about shims for the front and back rounded tapers to spread the loads there, too?

If you only shim the tops, the tapers become point-loaded. Recipe for failure.

this topic has been addressed ad nauseam.
it shouldn't be a problem if the top is beefy enough to withstand all the pull from the bolts. All Roberts boards sit on the tapers but I asked Rob if the top was strong enough to use a shim to make the mast sit on the top. He told me the top is strong enough. He even made me the shim to place in there. Also, with the tolerances the foils and boxes are built, for all three shims to properly sit you would need three custom shims for each combo.

I know there are many boards with broken boxes but I am pretty sure the failure rate is very low if we consider customers want the lightest gear out there and manufacturers try to deliver.



btw, Formula, where are you located? :)

@segler, thanks for the comments. In my experience, the modern foil boxes that have the chimney design, will hold up the forces even when both tapers aren't fully engaged. I've been riding such setups for three years now, on three different race boards, each one with a dedicated foil box. Each shimmed either at the front screw only, and lately properly with a full-length, angled shim.
As long as there is no movement of the foil during foiling (no noise, rake staying the same, bolts staying tight), everything works well in my experience.
Also, the foil bolts don't have to be excessively tight, because when shimmed correctly, the mast won't move. The forces on a 1 m wide board with 1000 wing and 10 m2 sail (setup I use most often) are probably high enough for a valid test, although I lack a few kilos for the proper IQ-foil weight :)

@Sandman1221 for the straight mast like AFS, Z-Foil, Recharge, and others that have the "Deep Tuttle" head, it's quite simple in my experience. Depending on the board+foil configuration, you can use:
- A custom angled shim such as the red one at the pic below (a friend had this with Recharge foil)
- Or a thicker angled shim (grey one below), eg. 1-4 mm at the back and 6-9 mm at the front (another friend of mine used that for Z-Foil)
Some measurements need to be taken beforehand, and once you have the desired front+back thickness/distance, we can work it out from there.

@WillyWind and @tonyk, my home spot is in the Adriatic sea, but I can easily ship worldwide if needed :)