Horizontal Battens

In order to make a non-overlapping jib as big as possible, leech battens are needed. Without battens, the leach of the jib would curl if the sail was not cut with a concave profile. By adding battens, the leech of the sail can be straight from the head to the clew, or even with some positive roach as shown. Horizontal battens are the most efficient way to support the leech of a jib or mainsail, since they are directly in line with the forces trying to make the leech curl forward.