Just a little addition.
Sand, fair (taper te hull) and glass 2" beyond the holes for structure.
Cover the gel coat with saran wrap. Gel coat will not harden in air.

: I have to relocate the hardware that secures the bungees that are between the
: cockpit and rear hatch. I am putting in a day compartment/hatch there. I
: need to plug 10 holes in the deck. Would this work? Epoxy in fiberglass
: patches under the holes and after it has cured fill in the hole with gel
: coat. I have some yellow gel coat that Eddyline sent me for free to fix my
: stress fractures on the rear deck. Thanks Tom.