Originally Posted by
kitsapcowboy
With respect, while it is both clear and intriguing how a clew suspension can reduce fiddling and increase both comfort and performance, I must admit that I was having trouble wrapping my head around how it would actually also save weight until I penciled out some figures. Devil's advocacy is not my strong point, but bear with me as I review some of my mass accounting, with the caveat that I have never researched or attempted a clew before and that there may be some errors in thinking or arithmetic...
If I were going to make a DIY 80" x 50" underquilt for an 11-foot (132") hammock, I might add two 80" x 5" folded fabric strips to the long edges for the primary suspension and two 50" x 5" folded strips for the cinch channels on the ends. In total, the channels add 1300 square inches, or almost exactly one square yard of fabric, 45 grams of added weight if I'm using fairly robust ripstop nylon fabric. For shock cord, I'd double the ridge line length (approximately 2 x 110") to construct the primary suspension and use about another 100" for secondary suspension anchored at the four corners of the quilt. Then I'd need another 120" to thread through the end channels. That's a total of 440" of shock cord, nearly 37 feet, at 2.12 grams per foot, or just shy of another 80 grams of added weight in cordage. Add a generous 25 grams worth of additional hardware and grosgrain ribbon, and you are looking at a grand total of 150 grams for all the rigging in a traditional primary/secondary channel suspension system.
Now to mount the same 80" x 50" underquilt on an 11-foot hammock using a basic clew suspension, one might use 8 shock cord nettles at each end (16 total). Assuming all of the fabric channels can be eliminated, the hammock body is 52" longer than the quilt (132-80=52), so you have to make up a distance of 26" on each end with each 1/8" shock cord nettle, which is a total of 416", or just under 35 feet, weighing about 75 grams. For attachment at the short edges of the underquilt, a set of 16 KAM snaps and two yards of 1/2" grosgrain ribbon weighs just under 15 grams. A pair of SMC descender rings to collect the other ends of nettles for attachment at the gathered ends of the hammock weighs just over 20 grams. If you opted to use LineLoc 3s to make each of the nettles independently adjustable, you could do so by replacing the KAM snaps at a weight penalty of just over 10 grams. Unless I am missing some additional hardware, a modern shock cord clew suspension could be used to hang the same full-length underquilt for a grand total 100-110 grams, somewhere around an ounce and a half less than the standard rigging, which does indeed jive with the reported weight savings. (In truth, the assumptions and estimates above are necessarily rough, owing to both stretch and trigonometry.)
However, it occurs to me -- and seems important to consider -- that as the underquilt gets shorter, the weight savings of the clew suspension versus the standard is lost. Reduction in the length of the underquilt will mandate proportionate lengthening in two lengths of shock cord in the secondary suspension of the standard setup, whie the length of the primary suspension remains unchanged; conversely, the same length reduction in a quilt hung with a clew suspension will require proportionate adjustment in eight pairs of shock cord nettles, adding approximately four times as much weight for the same change. (Again, owing to stretch and trigonometry, these are ball park estimates, but you get the idea...) Fortunately, shock cord doesn't weigh very much, but I think it's fair to note that suspending less quilt with more shock cord could begin to cut into the weight savings.
Regardless, I think clew suspension is a clever innovation to continue exploring for all the other reasons cited to date in this thread.
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