There was a CSY 44 next to us in Bocas Del Toro that had new chainplates put on the outside of the hull and just bolted through the fiberglass with a backing plate.

They were beautiful. The plates were made as a large (6" diameter) circle with bolts about an inch in from the outside in a circular pattern. There was a foot long tang that connected to the standing rigging. It was strong, easily accessible and looked beautiful.

Something like this.