Hello, I am in the process of repairing airline cracks in my gelcoat below waterline, I stripped the hull and noticed smal bumps of hard gelcoat in the hull, when sanded the bumps dissapear, what are these, could it be that the bumps are the result of molds that had hard gelcoat particle left in them at the beneteau factory when they gelcoated the hull, my boat is 1985 325 first.