For fuller bellies or for furling
Do you mean a thin string that has a very diminutive plastic jam cleat too?Might be for giving the sail a fuller belly for light winds. Your main should have it too.Pull down on that string, then up to cleat it, and will ive your sails more belly to catch those very light airs.You can release and relax them when the wind kicks up to flatten the sails and spill more wind. This line is along the leech exiting at the clew.OR...if you mean the string is at the tack - where the jib hooks up to the furler, then I haven't got a clue!!I can look at mine - it might be needed to help the furling mechanism furl the sail. I'll look at mine when I get back home. Or, call Hunter and they will explain it. I know the line you mean, and it's a mystery to me. Let me know what you find out!Enjoy!