Still, leech-shape control remains an issue, and here, too, embedded pro sailors have devised a solution. A typical leech cord could be 150 feet or longer, and tightening it merely takes the stretch out of the cord. If the wind goes light, the leech line recoils when it’s eased, resulting in excessive hook in the back of the sail. Then, when the sail is furled, the hook creates compression; the sail puckers on itself and creates folds, which become cracks; and the sail wears out faster. Smart Rigging’s solution, says Zebny, is a PBO sling similar to what you’d see on a furling cable or a shroud. It’s expensive, but with less stretch, there’s less recoil. Add in the furling leech battens, and flutter is a nonissue.