Actually, my transaction was quite simple. Submitted written list of questions and proposed contract to seller. Seller answered questions in writing and approved proposed contract. Inspection by me and sail with owner. Signed contract with deposit on the spot. Survey by marine surveyor. Re-negotiate contract for unseen deficiency revealed by survey. Closing with cash, no problems. Sail away to new marina. Seller buys bigger boat he wants. Everyone is happy.
The seller was a reasonable man, also a lawyer. We were both familiar with using contracts and negotiating. We both recognized motivation on the other's part and appreciated having someone who knew what he was doing and who also wanted to complete the deal. We both got what we wanted out of the transaction. Win-win situation with no demanding and/or deceptive broker (pretending to be an expert) in the middle.
I've had two good experiences buying boats in recent years. The first was similar to yours, buying directly from the owner (neither of us were lawyers however). The second (recent) sale was handled by a broker and I can't say enough good things about the broker. He called me shortly after the survey began (I wasn't able to get there for the start) and told me they found high moisture readings in the deck and asked me if I wanted to go ahead with the rest of the survey. I told him that I did, but wanted to hold off on the sea trial until someone from my marina could provide an estimate for the deck repair. The broker agreed, contacted the owner, who also agreed, and we proceeded.
But there's more. After getting the deck inspected and receiving the estimate for the work, the broker felt the estimate was too low
(i.e., he thought the damage was more severe). He contacted the yard, arranged for them to come out for a second look and revised estimate, which we got. It was higher than the first (the guy who I wanted to look at the boat was away and wasn't able to do the first estimate).
I don't know how common this kind of thing is among brokers, but in this case this particular broker definitely saved me a decent amount of money. The survey also turned up some less serious issues and the broker arranged for the owner to address those prior to completing the sale.
So I guess my basic point is, there are good brokers around.