Originally Posted by DemostiX
My question is only about what you exclude in your second paragraph, the part that is acting as rails. I can understand that only makers for gram-counters, a Z-packs, would swap out the length of shock cord in the channel for a length of something lighter, but that is exactly what I am driving at, if an ounce can be saved and nothing at all lost. (I might even bury the shock cord in a nice continous splice.)
I'm much taken with your observation-- with others -- of the sealing problem of UQ's. I'm trying to appreciate just what shock cord is supposed to do, as obliquely as the forces of the UQ suspension are applied. Before butchering a fine continuous stretch of shock cord on a full length UQ, I wondered what functionality I'd be giving up.
RAB closes the stuff sack for the Quantum top-bag with shock cord, including a very nice (or over-engineered) stress-stopper and then a keeper for that stress-stopper. Wow, no expense spared. Then, of the shock cord, I wondered: "Why? What need does this meet? In my limited experience, I haven't noticed shock cord on a stuff sack closure before. What did I miss out on? "
My reasons for a hybrid bungee/rope suspension were twofold. First, I didn't have enough bungee for the mammoth sized Brazilian. Second, the longer the bungee the "softer" the spring, which can result in sag. Amsteel runs thru the UQ channels, selected to avoid abrasion of the fabric. My thinking is that as long as part of the UQ suspension has stretch it should provide the same result as an all bungee system.
For the end channels I have some UQs with bungees and others without. In theory and according to the Jacks you shouldn't need stretch in the end channels because the suspension bungees provide the needed movement. In practice I find that having bungees in there just works better. But still not good enough, which is why I've been suggesting the need for draft tubes.