Sailed last weekend with 730/100EVO/200 and 7,8 sail in 10 to 17 kts of gusty wind.

I used a 0,8 shim, that felt good but maybe I will try even a 0,5 shim. I feel that the 730 needs less shim than the 550 that I ride with a 1,0 shim. In the gusts a smaller sail and/or wing would have been better but I was able to stay in control (long harness lines help with that).

I was stable upwind and cross wind, but downwind I felt that the nose was dropping down a bit. So I put the PDM 0,5 cm back to 108 cm from the foil front srew and put 2 clicks more downhaul (with the Duotone Power XT) on the sail. Then it was much better downwind and 1,5 kts faster than before.

0.5 cm is nothing at the mast base.
But indeed more downhaul will give more twist to the sail and a flatter/ faster profile.
So less pessure from the sail (especially in the top).
Another way to deal with minor front/back stability is to move the wishbone. Up 3-5 cm in such case is a very easy and quick thing to do.

_________________
Je m'en remets au vent.

Franck
https://free-ride-addicted.jimdosite.com


Patrik Aeon ailes 650 + 450 + 350 fuselage V2 et v3 stab 160 et 150.
Planches: 2 home made carènes rondes 70 et 76 de large + gun 212x59 (à vendre),
Voiles: MauiS2 Venom 7m², Patrik HA 5.6, foil S2 4.8, GT3 7m² (à vendre)
Torro 4.0, Blow 3.3,

1m76 66Kg

I definitely feel +/- 0,5 cm at the mast base. I really recommend to try different mastbase positions as it has a huge impact on how the board reacts.

+1

Quand je passe à l'aile S840 à réglage de stab constant, la position du pied de mat est -0.5 pour retrouver le même équilibre que mes autres ailes.

Do You change the backwing shim with different sails, or do You use one shim size for every frontwing?
I use a 0,8, shim for the 730 Phantom Iris R wing with 7,8 and a 0,5 shim with 9,0. Pdm stays the same at 108,5.

If I use 0,8 shim with the 9,0 I would have to take the Pdm back 0,5 to 1 cm.
Whats better from Your opinion?

It doesn't matter as long as you have found the good setting. But in my opinion, as a 9m2 is not really for speed, i would probably use more shim angle to keep upwind power. So 0.5 with the 9m.