There are two that I use. They're both in Huntington, NY. North
Sails has a loft in Huntington. Do does Doyle
sails, their loft being near the Huntington Rail Road station. I've used both, and they're both excellent.
Let's see here:
Doyle Sails: (631) 673-5055 - ask for Mark or Dean
North Sails: (631) 421-7245 - ask for Chris or Tom
Hope this helps.
Peter