Matt finish makes water wet the hull, which in turn reduces friction. Several products have been proposed to reduce friction, but none works really better than water itself. Also they tend to increase weight while sanding (one popular way to get matt finish) does not. You can see that a surface is properly wetted when water forms a thin continuous film on it rather than individual drops. A well wetted fin will resist spin-out better. However be carefull not to alter the shape when sanding your board or fin.
Last edited by Farlo; 20th May 2009 at 05:42 PM.