Nauticalrich: You said: “It was stated…that the hull was in good condition, nothing wrong with it.”
If you can prove that the seller made that representation to you, knowing that you would change your position in reliance on that statement (i.e. spend money for the haulout and for the survey), and that, but for his false representation, you would not have spent that money, then you have a basis for a lawsuit. This is especially so in view of the fact that he profited by his false statement. (It saved him the cost of hauling the boat for repair.) Your state probably has a small claims court, where you can sue him for a relatively small amount without an attorney, and using very simple procedures.