Hole from foam filling -cap popped

[SkaterRace]

I have this hole in my bilge and have been fighting to even get a quote on fixing it. Wondering what it would take to do it myself. Its about 1/2 inch wide.

Some sources online say 5200 will be good enough others say it needs fiberglass. The disk is what I presume to be a cap or something over it.

What would this forum suggest?

 

[MikeSchinlaub]

It's nothing structural. If the foam is dry, just fill and smooth it with some good epoxy. When it hardens, sand it smooth and paint white.

If the foam is wet, it will start causing any wood to rot. You can either ignore it until you have to fix it or cut it open now to investigate.