Fibreglass hull damage repair advice

Gday, I am looking at my first trailer sailer a 6m Sonata swing keel, on inspection it all looked pretty good until I opened the veberth and smelt fibreglass ( i used to repair my own surfboards) Immediately caught sight of a patch about 450mm long and 250 mm wide, typical blueish colour of a Mitre 10 repair kit.
I told the owner "this boats been holed through" he reckons "no way , not under my ownership" (five years). Ok I say so we look underneath and sue enough blue resin repair visible from underneath outside smack in the keel about 1500mm aft of the stem, from outside the hole looked about 100mm long x 50mm wide, no gel coat applied.Owner says he didnt do it, owner says never showed and signs of leaking v berth always dry.
He is willing to drop a grand on the price to cover any "future issues".
Questions:
1. it does not look like a boat yard carried out the repair work or else surely Gelcoat would have been applied, is that a reasonable assessment?
2. How successful do you think such a plug and patch would be?
3. whats the chances that such a repair could come unstuck in the future?
4.If I did buy it is it possible for me to do a professional and lasting repair on it given that I am a carpenter /joiner with 35 years hands on and multi skilled and have worked with fibre glass on my own surfboard repairs as a teen? Im a pretty fussy and thorough tradesman and given the correct proceedures can usually pick up the idea very fast. I have yard space and loads of tools not that I would think Id need too many tools.
5. Or should I just say no thanks and keep looking? the market does have a lot of boats around the $7500 mark .
Thanks to any and all who respond. Cheers Busterboy

 

Without a few pics there's no way for anyone other than you to give an opinion.

 

Welcome to the forum.

It not necessarily correct to assume gel coat was used by a yard. Paint is easier and cheaper (usually). Most of the other questions will require more detail and some images. The owner may also be correct in that he didn't notice the impact or any leaks. The boat's liner would have masked any leaks and/or there aren't any (yet), because the laminate is still fairly intact, just busted up a bit. Lastly, sure you can easily handle the repair, assuming some reasonable skills and it's not too big a job. If you do buy it, consider getting access below the liner to see if there's water or water staining in there, near the damage and also the lowest point of the bilge. This would indicate a leak, though once repaired, you'll be tight again.

 

I'd ask for $3,000 off - its a lot of mucking around, and the materials aren't all that cheap especially when you include consumables.
I'll just remind us all of what we all know by experience - always double the expected time and cost + 10%.
Like Par said, fibreglass hulls can usually be effectively fixed. It's just how much you value your time.