Strip all gelcoat, or patch?

[Assassin]

I would also research the manufacturer and any problems with that specific, or batch of hulls and see if there were problems and what they were, and how they were rectified, and who recitfied them as this may all be useful information and the internet will often provide such information. If a contract company did the rectification work then looking at their web site may yield useful information about the problem and how it occcurred and this maybe an indicator to larger and more significant problems.

Surveyor, and take it from there.

 

[Deleted User YDKXO]

BUT, and it's a big but, I was thinking to suggest that friend of mine to have ALL the gelcoat stripped, up to the w/line.
In fact, my impression is that it could take not very long before, after putting the boat back in the water, some other gelcoat detachments develop in other areas.

Thats the real point isnt it? How long is your mate planning to keep the boat because its almost bound to happen elsewhere on the hull sooner or later? If its only another season or two before selling, I would say patch and re-antifoul and hope that the buyer's surveyor doesnt pick it up. If on the other hand, the boat is a keeper then I would say strip off all the gelcoat below the waterline as you suggest

Merry Christmas to one and all on here!

 

[MapisM]

Thats the real point isnt it?

Exactly.
And since the owner is actually happy with the boat in all other respects, I think it's reasonable to call her a keeper, in the foreseeable future.
I should soon be able to have a look at the thing in flesh, btw. Looking fwd to that with some curiosity.
Likewise, merry Xmas also from my part, albeit a bit late...

 

[Croftie]

My thoughts would be to

Remove all antifoul
Allow hull to dry out, possibly several months depending on temp
Remove any loose edges and check extent of problem
Epoxy fill bad areas, sand re fill until smooth and blended
Min 2 coats of 2 pack epoxy primer to seal edge of gelcoat to epoxy
Re antifoul

A sort of halfway between a quick patch up and a full strip and re gel

Edited to add; Obviously ALL surfaces should be well keyed before applying filler / next layer / epoxy primer etc