A year or so before my Willard 36 was listed for sale, I saw her on the docks in Emeryville CA (near Oakland). I left a note on her asking owner to contact me if interested in selling. I never heard from them but saw the boat was for sale via a broker. Rest is history. (1998 or so).
If the vessel you are interested in is in a marina, stop by the harbormaster office and indicate your interest. Chances are they won't give you the owners contact information, but would be happy to forward your information to the owner.
Don't give up. If not for sale today, might be in 6-months. As moderator of the Willard Boat Owners Group, I can tell you that patience and tenacity are a virtue.
1970 Willard 36 Sedan Trawler