I’m having a hard time processing that you bought a boat used, it’s 20 years old and after finding an issue the manufacturer is willing to grace you $3,000 towards its repair.
Who does that? Try buying a used car or anything else for that matter 20 years down the road and getting the manufacturer to fix it. They’d think you were nuts.
There’s a thing called buyer beware. When you buy anything used you do your homework, hire a surveyor and take your best shot. It’s still a crap shoot. Most times you do ok but sometimes the law of averages catches up with you.
If anything the surveyor may be able to reemburse you for his fee if he missed something blatant.
If the offer from Grady still stands I’d gratefully accept it and hunt for a repair shop that will give good work at a good price without taking a year and a day.