Last summer we spent a few days swinging around on the hook not far from a boat that had a small "sail" somehow attached to his backstay. It appeared to be doing a job holding his bow to the wind and minimizing the swinging. By the time the weather cleared up enough to pay a visit, he'd left. Has anyone used such a sail? If so, any comments about it's usefullness? Does this "sail" have a name? Thanks for your help. jmgintc@aol.com