FRP Board Delamination

[Demon]

This board came with a boat I bought. The person said they left it under their boat cover. You can see two pretty big spots and there is a smaller one. They are rigid. The board does not go down in the slot. I have spares.

My thought is sand it down and rebuild.
What would be the best fill?
Thoughts?

 

[SailorHD]

I would take a side grinder and completley get rid of the bubble . That will probably leave a large hole . I would fill with formula 27 (white marine filler) then grind it down until I had about a 1/8" to go and then get some epoxy resin and I would use carbon fiber cloth or fiberglass cloth and fill until it is even and sand and paint that spot...I have bought the supplies online .

 

[LVW]

New issue to me.

After grinding...

Find some firm plastic film (epoxy won't stick to it), lay on the curing epoxy, and let cure/form inside the daggerboard trunk?

Remove, sand to fit better, allowing for temperatures to swing, allowing ready movement?