Richard,
When you do your repairs I strongly recommend you use epoxy, not polyester (or Vinylester) resin. If the base material is sound it should make a much stronger repair.
Also I am kinda intrigued that the damage from the trailer has worn through the lay-up to the wood core. Why not put some stainless steel strip on the bilge keels to protect them, it’s not just on the trailer that the keels can encounter something hard and rough…