Best position for mounting the foil

I will start efoiling using a quite big kite race board, the Airush Monaro V4 69.5 x 189.8 cm I found used for a cheap price. I will then use a smaller board that I already have. My foil is a Rocket Foil from Liquid Force. How could I know where it will be the best to mount the foil? (centered of course for the width of the board, but for it’s lenght?)

I want to know too

Depends on board size. Not as critical as on a kitefoil board since you are strapless
Based on my readings, it is actually not a fixed position, its is a range of positions around 25% of board length.
If the board bottom is not flat, you can move the plate fore or aft this quarter length position by 2 to 3%

The middle of the plate (also mid chord) to tail edge distance
Mid plate position = (board length /4) +/- 2%
Example for a 1.9m board: 1.9/4 = 48cm +/- (1.9 x 0.02) so plate position is 44 to 52

8’ - 22" = 60 +/- 5 cm
7’ - 20" = 53 cm +/- 4cm for 2.1m board
6’ - 18" 1,80m -> 45 +/- 4 cm
5’- 16" kitefoil board 150cm = 38 +/- 3 cm that is 35 to 41 cm

Then, be careful how you drill the board to mount a kitefoil or SUPfoil hydrofoil because 4 holes will create weakness points.

Best and cheapest method (Credit Aventout on the French Kitefoil Forum):
1- drill 4 holes (usually on a 165 x 90 mm pattern) with 9mm bit through board top and bottom
2- Mount a Allen wrench with 12 or 13 mm shorter side on a drill . Empty inside each 12x2 = 25 mm diam hole with Allen wrench between top and bottom skin without removing the skin which is essential for future strength. Holes bigger than 28-30 mm in diameter could make the board fragile.
3- fill holes with epoxy resin and micro balloon mix or resin plus fibre cuts with slow hardener (to avoid exothermic reaction that will melt the XPS inside the board)
4- wait until set/cured (could take 2 days) and drill with 8mm bit (not 9mm) for 8mm screws and bolts (A4 316 Stainless Steel)

drill 9mm


Thank you for all these amazing infos!

Note to new guys who are modifying surfboards or SUP’s. Kiteboarding are constructed differently, don’t use this method on a traditional surfboard or it will likely just rip through. Surfboards need much more reinforcement as their skins tend to be thinner.

Best to route out and put an insert in of high density foam and mount2 longboard single fin boxes in as tracks.

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