[mitiempo]

How about digging out a quarter inch of core material from the inside of the hole, sealing the bottom of the hole, filling it with thickened epoxy and re drilling the correct size?

It won't be cored.

 

[mitiempo]

Perhaps not with wood, but I was referring to whatever the core of the hull is made of, something is between the gelcoat. It's just the concept of creating a groove to hold the epoxy.

Fiberglas through and through with gelcoat on the outside.