[abl1111]

I know how I would do it. Basically your going to make a mold out of cardboard, place it in through the hole and hold it place by pulling it toward you w/ string.

Take a flat pc of card board - like from a cardboard box. Cut it 3/4" larger than the dimensions of the actual hole.

Make a small hole in the dead center middle of the cardboard. Take a pc of twine and thread it thru and make a big knot so the knot won't get pulled through the hole.

Wet out w/ resin (2) plys of mat and place it on cardboard - cut mat so the string can run through it. Then, take a little resin and wet out 1" of the inside lip of the hole.

Then, bend the cardboard a bit and push it through the hole w/ the wetted mat laying on the cardboard. Make sure mat is laying flat. Align it all and pull the twine to you w/ the cardboard/mat laying flush against the inside of the hole.

Pre-think this part: Either put a stick in dirt near the boat and tie the twine to it just enough to keep the cardboard in place ( or use a big planter w/ dirt in it )

Let this cure. Cut twine off close to cured fiberglass. Then, lightly sand fiberglass.

If you've done the backs then the rest is cake.

I would then use stuff called Dura Glass or something like it ( it's a thickened resin and glass mix ) or use resin and cabosil to a putty texture. With a squeegee, smear it on to the fiberglass - fair it out. Leave enough room for some sheets of mat and gelcoat and you're home.