Or Tartan 10: http://www.yachtworld.com/boats/1979/Tartan-10-2407460/Glen-Cove/NY/United-States
Tartan made a 31' though. That is why I am a bit confused about the model. I saw no adds for a 'Tartan 31' at yachworld; only the 33' T 10 listed in Glen Cove.

I have an affection for the Tartan brand but it started with my 1967 T27 which I bought over 10 years ago and I am sticking with it. Still curious if that is your ad though.
Hempstead Harbor can make a nice home port. I know it well having grown up there.

Yes. Everyone has one: http://www.odalisque.us/