I've just (finally) finished re-rigging an older CS 17 (#218) from a sock-style sail to the new new sail track. I have new sails and am very happy with the performance of the boat thus far. Thanks to everybody who gave advice along the way. I have a more basic sail question that I need help with. In the picture below, you will see two grommets on either side of the clew where I have affixed a snap hook. What is the purpose of those grommets?