Abstract: A waterproof fabric cover is placed over the top of a cotton module which is a stack of compressed raw cotton having a rectangular horizontal cross section. The cover typically covers only the upper half of the module and frequently only the upper quarter or upper eighth. The cover has side walls longer than the end walls and these long side walls need hold down structures to hold the cover on the module during high winds. Secured to the bottom edge of the side walls are loops that are shorter in the center of the side wall and longer on each side of the center loop. The bottom ends of these loops define points on a catenary curve. A girth cord is passed through the loops and around the ends of the module at a level below the loops to define an approximate catenary curve along the side walls.