a boat can be very emotional and I think it's important to keep your expectations in check. I would caution you to be prepared to walk away from the deal if it doesn't feel right or you can't afford the price
. I also suggest that you offer to pay only what you can comfortably pay. That way, if you buy the boat, you can afford it. If you don't buy the boat (due to price), well, you couldn't afford it anyway.
All that being said, I must admit there is a magical feeling once the deal is completed and you're sitting aboard or you're out sailing and you can say to yourself, "This is mine."
Good luck, fair winds and calm seas.