For advice on making repairs to a Unibond hull of a Boston Whaler boat, see the FAQ at
https://continuouswave.com/whaler/reference/FAQ/Read this answer
Q5: how is damage to a Unibond hull repaired?https://continuouswave.com/whaler/reference/FAQ/#Q5In the case of a circular hole in the deck that passes through an area where there is wood reinforcement, cut a suitable wood plug in similar wood--typically marine-grade plywood--using a plug-cutting tool. Install the wood plug into the hole and use wood adhesive to retain the plug, Then complete the repair of the hole using epoxy resin with filler material and possible a top coat of gel coat resin to obtain a good color match and UV resistance, if the location of the repair will be visible and exposed to sunlight.
If the area to be repaired is in the non-skid pattern area of the cockpit or deck, the gel coat resin surface area of the repair can be made using a non-skid mold pattern. You may be able to make your own non-skid mold pattern by taking an impression of the non-skid from another area where there is no damage.
For advice on how to take a pattern from a non-skid area, see this prior discussion:
Reproducing Non Skid Patternhttps://continuouswave.com/ubb/Forum3/HTML/014099.htmlAlso visit
Gibco FlexMoldhttps://gibcoflexmold.com/boat_manufacturer/boston-whaler/Also, consider that if the existing hole in the deck will not be in a highly-visible area, there is really no need to restore the non-skid pattern.