JRB gets huge points for realizing the potential for down quilts under hammocks, an insight around which they built a great business. I learned about hammocking seeing pictures on their website of their quilts under Hennessy hammocks. BUT perhaps you have to have lived with the necessity of fidgeting with the tension to avoid compression on a "flat" quilt---which for quite some time was all that was available from JRB or anyone else---to appreciate the comparatively no-nonsense approach possible with a differential cut. So fine, the idea of shape forming fabric existed long before underquilts, and the SnugFit was an application of it. That's where genius lies usually, in making connections, bringing insights from one domain into another. Einstein couldn't have expressed general relativity without the already-developed (and at the time greatly under-appreciated) concepts of Riemann's non-Euclidean geometry.
Another point of genius is realizing that the same effect can be had with much less effort in darting, and those points go to JRB, for when they introduced their differential cuts, that design was a great deal simpler then Youngbloods, which translates into lower cost and greater access by the consumer. The other differential cut quilt makers have followed that lead.
Credit should be given to the right trader in technology; but confusing trading with invention is a mistake, and an important one if honor is given to the trader instead of effort at understanding of the device, the problem, and the engineering to solve it. (Now let us read and praise Henry Petroski....or the engineers and technicians he praises)
For a cylinder, which a bridge hammock is often modeled as, there is only some small inefficiency and extra fabric in a non-differential quilt. You've drawn attention to common tailoring craft and away from the source of the instrumental benefit, which is warmth-preserving fit. Where does that benefit, fit, come from? Just from drawing the bottom layer fast to the hammock bottom from the right attachment points. With a differential cut it is hard make those attachments incorrectly. With an adapted plain-cut quilt, one must be careful to attach and pull from the top layer of fabric. That done, the plain box quilt is just as snug, albeit with randomly pleated and therefor wasted fabric. (Make the mistake-- which might be an attachment point for the suspension just 1/4" away -- and the bottom layer gets pulled, compressing the chambers and indeed compromising the insulation. Baffles "overfilled" when scrunched? Minor impact...or use less down.) With the lightweight fabrics used-- we're not talking blanketing or denim -- the costs are small.
Inelegant? Yes, but hardly as untidy as ignoring all those furrows and valleys at both ends of gathered end hammocks, tailored and un-tailored. And I haven't even gotten to the claimed problem that there are fit-problems on a bridge modeled as a cylinder and not an hourglass.
Anyway the proof is in the pudding: With all the differential UQs, larger improvements in utility and freedom from operational failure are coming from changes in the suspension and fitting of draft stoppers, the latter being commonplace engineered features of sleeping bags.
Putting this comment directly back on topic: The OP was impressed with a design which was not only not original to the maker, but ordinary in the context of endless innovation of tent designs for even the mass market, let alone the sophisticated hiking / expedition market.
None of this -- or nightly familiarity with the hoops of the Clark NX hammock pulling fabric -- has me admire less Paul's (AHE) introduction of his new tarp, with all the technical and supply-chain development required to accomplish it, and at a price I find surprisingly low.
Last edited by DemostiX; 02-24-2012 at 21:45.