Hi Juan, overpowering might not be the ultimate secret but underpowering is definitely not good. A well powered sail with a small fin does better than an unpowered sail with a big fin. Of course the fin shall not be too small. My own findings are that the length in dm shall not be much smaller than half the surface in sqm. For instance I use a 43 cm fin with a 7.3 sqm sail on a 103 L / 64 cm wide board in light conditions (12/15 Knts). In stronger wind (15/18 Knts) I just flatten the sail, put a 36 cm fin and it goes upwind as well. At a steady18 Knts I will then change the sail to a 6.5 or 6 sqm and keep the same fin till ~20/22 Knts, then go for a 32 cm fin. Mastfoot in the front will help the rail to bite and compensate for a curved fin, but you need to have some volume in the middle. Rear straps outside helps a lot just by making it easier to balance the sail pressure. Long lines and/or low boom do not prevent me from pointing up provided that there is enough wind. Hope this helps...
Last edited by Farlo; 3rd November 2008 at 11:32 PM.