MORE CLOTH SMARTS

Polyester fibers that make up Dacron sailcloth degrade at the same rate from UV exposure. However, differences in the yarn sizes make or break sailcloth strength. Exposed outer yarn fibers degrade from UV exposure. And they act like sunscreen to protect the inner fibers. But small yarns have few inner, undamaged fibers. This is why we orient the tear test with the cut parallel to the fill yarns. It’s the smaller warp yarns being tested. And this point is a consideration for new sail choices. High-aspect Dacron uses small warp yarn to dedicate great fiber density in the fill direction, thus making the warp yarns more susceptible to UV degradation. This is the case of failure for most Uv-damaged sails. Low-aspect Dacron is a better choice for tropical sailors, even with a high-aspect-ratio rig.