I Googled CT for you:
http://www.ct.gov/dmv/cwp/view.asp?a=801&q=253552Quote:
Is there a exemption from registration for any vessel less than 19 and 1/2 feet in length without any motor and is not a motorboat (such as a sailboat powered by sail alone and no use of any motor)?
Yes. Those boats are exempt from registration.
In PA, we have the option to register or to get a launch permit. I noticed that some surrounding states would recognize PA registration, so it seemed easier to register if I planned to sail in multiple states. Not sure I was right, but that was my logic.