For the non-Dutch amoungst us: If you are not secretly embarassed by the offer you are initially making, it is too high. When you are turned down, walk away, making sure they have your telephone number. Boats don't usually sell really fast. Wait 2-3 weeks, call them up and ask if they have re-considered your offer. Then "imply" that you might have a little wiggle room, but would need to look at the boat again. It doesn't hurt to show up with the money in cash. It will be imperative to get a signed receipt if you pay in cash. The sight of a wad of greenbacks, which might be construed by some as unreported income(!), has swayed more than one seller.
All those "killer deals" you've heard about-well that's how they got done. The seller has to want the boat gone, and be under the impression that you are willing to walk away.
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.