Board base preparation

[ulysses]

Does sanding a boards base increase its speed or lower its planing speed? And if so, does anybody know where to find information about how to do it?

I read a reference somewhere to racers sanding the bases of their boards, but have never seen any other discussion of it. Nordic ski racers have long sanded their ski bases to reduce suction and increase speed, particularly in wet conditions. I assume the same principle would work for windsurfing!