martin crashed his fin first. Then he pushed it into the sand bank to remove the worst of the debris. then he caught a gust and went over 50 knots with a fin that was really lessed up.
Polished sanded? hehe dont think he cared!
so why is sanded good for a fin? why do you get bad stall? earlier in the thread i said about the reatachment of flow. it can be argued that sanded will be better rearwards on the chord in order to promote reatachment after the seperation bubble. Forwards of the seperation bubble polished will be good in order to delay seperation in the first place. Sanding is all about giving more friction for the water to stick to, good for a turblent flow section maybe? not so good for a lamina flow section?