It looks like that the Wood layer on the bottom of the board has released in an area of 2x5cm, it create a small bubble, whats the best way to fix it? By the way is their any fiberglas on top of the Wood.
Remove the epoxy sandwich where it has separated from the inner foam. Feather the edges. Rebuild up all the epoxy sandwich layers, apply constant pressure while the epoxy cures, use vacuum bag or a weight to apply pressure. Sand, fill any hollows and resand. Google "The Board Lady" for details on this type of repair.
If its just a bubble it is far more likely to be a paint bubble...... is it standing proud of the surface and you can feel it go up and down with light finger pressure?
Or is it still flat and can be pushed inwards?
It looks like that the Wood layer on the bottom of the board has released in an area of 2x5cm, it create a small bubble, whats the best way to fix it? By the way is their any fiberglas on top of the Wood.
In answer to your question, if its the same construction as my 2007 formula wood that I'm currently restoring, and I assume that all starboard wood boards are the same construction, there is only a very thin coat of paint over the wood on the bottom and nothing but the grip coat over the top where the wood is visible. No glass or resin whatsoever!