---

This question has been answered here a thousand times already, but here it goes again.

The screws are #10, so drill out the holes 3/8" (twice the screw diameter) all the way until you hit foam.
Pack the hole flush with "white Marine Tex" epoxy, wet sand flush, buff up gelcoat area as necessary to original shine. the Marine Tex will bond to both the fiberglass skin and the wood underlayment.
Center punch the center of each filled hole, and re-drill for the #10 screws. Be sure you drill a large enough hole, so the threads only bite into the epoxy.

This will be a permanent fix that will last forever, while at the same time not letting in any water, since the screw is totally encased in the epoxy plug. The white fill will not show under the rail base.

I did this exact repair on the bow rail bases of my Outrage 25, 20 years ago, and they are still rock solid.