Re: Yet another what is this rigging question.
Cunningham was my bet too.. if so the other end likely has a hook on it, to hook it onto the cringle just above the tack. Sometimes rather than a cunningham hook, the line goes up, through the cringle, and attaches back to the boom (or mast).
Ooh a reference back to this site... I love it
Hull #68 S2 7.9 on our little landlocked puddle, Lake Wallenpaupack, PA, it's cheap, trailerable, and paid for.