Sailcloth is woven on a loom. At the beginning of the weaving process of a crosscut dacron, large spools of warp fibers are wound off a creel through fairleeds onto large warp beams. The warp beams hold thousands of fibers before feeding them onto a loom. The warp fibers are then fed down the loom and go "over and under" fill yarns, which are shot across horizontally. During the process of going "over and under" the fill yarns, the warp yarns crimp. 

The picture to the right shows a crimped warp yarn on top, and a straight fill yarn on the bottom. Crosscut oriented sailcloth is stronger in the fill direction because the fill yarn is already straight. It is more prone to stretch on the warp direction, because the warp yarn can have it's crimp pulled out of it

 

Challenge engineers design constructions to optimize threadline strength. 

 

The picture to the right shows a microscope photo of sailcloth, that has been specifically dismantled to demonstrate crimp.

The fibers going horizontally on the picture are the fill. The fibers going vertically are the warp. As you can see, the fill is straight and the warp is crimped. 

Challenge Sailcloth designs each warp and fill yarn, taking into account many factors, including denier and tenacity. We use numerous combinations of warp and fill constructions to generate the greatest mechanical advantage in sailcloth. 

The more times the warp and fill yarns Interlock together, the strong the sailcloth. Challenge Premium Fabrics have the highest interlock count of any woven cloth in the world.