First.. is the 33 still for sale?
Second.. Make sure you post in your ad that emails have to have a "key word" in the subject or body of the response. I delete most of the emails i get off CL and oodle. AND I will tell you who is the worst offender for phone number mining/ calling.... even when you list that 3rd parties are NOT allowed to contact you... BOAT TRADER... They even called me on a set of fenders I listed on CL, wanting to sell me an ad on their website.
I see many of the guys choose the "no email" option. If they are serious about your boat, they will call. It will also weed out a lot of the "mental m*sturbat*rs who get off by asking for pics... talking the game...etc.