The change of the rake angle results in a change of the aspect ratio, the outline and the torsion of the fin. In addition the power-point of the fin will be shifted with consequences for board and sail trim. With increasing rake angle there are several parameters changing.
- Lift distribution is decreasing
- Resistance is increasing as the three dimensional flow is increasing
- The break-down of flow is setting in earlier (longer fins)
- Stability increases with higher speed (and shorter fins!)
In general one can say that the shorter the fin the greater the rake. Especially in high winds, the fin should be as short as possible to gain enough control and manoeuvrability.
If you are sailing with a Formula fin you should pay a lot of attention to the rake angle. Depending on the sailing conditions angles between 1 and 6° have proved to be quite successful.