Where is shock cord needed on an under-quilt (UQ)?
The ends of a gathered-end hammock vary in width between set up and use and during use, so the role of the elastic to have the width of the UQ ends track that width is clear enough, I guess for sealing against intrusion of air.
An elastic suspension stretches the UQ out and up to rest loosely against the hammock bottom.
But , what is the purpose of the 4 yards of elastic within the two channels of a full length UQ, when there would seem to be plenty of static and dynamic adjustibility from the rest of the shock cord running up and out to hammock ends?
I'm pleased with the fore-and-aft sliding on rails with the side channels. But, I'm not understanding the role of the elastic as the rail.