I will tell you soon about the glamorous D.A.R.T. tarp that Kitsapcowboy had built for me. It was before the tarp became available at DWG. I am not a gram weenie (as you can guess looking at my tummy) but I thought I should pair my new skimpy tarp with a lightweight underquilt. So, I ordered a customized Selva 250 underquilt from Cumulus, a polish brand renowned for their down sleeping bags and clothing. Recently, they extended their products to quilts and hammock gears. The quality and craftsmanship of their products are terrific. They are happy to do custom work. Pricing and lead time are very reasonable. Cumulus people are very kind and responsive. I usually interact with Rafal Buczek who knows a lot about outdoor equipment. Shoot him an email and he will help you selecting/designing your new gear. Given the prohibitively expensive import charges, Cumulus is really a convenient option for EU hangers.

http://sleepingbags-cumulus.eu/uk/ca...s/hammock-gear

This is the second Selva 250 that I am purchasing from Cumulus (I also own a Panyam 600 sleeping bag that I am very happy with). For the first Selva 250 UQ, I decided to go standard for the fabrics (Pertrex Quantum) and down fill (8.8 oz of premium 850 cuin Polish goose down). It is worth mentioning that fill power rating slightly differs between US and Europe. The units are the same i.e. cubic inches. The assays are based on the same principle (i.e. volume occupied by a fixed amount of down subject to a given pressure) but differ in some technical details. The conversion factor between the two ratings is not entirely clear. However, it is commonly accepted that 850 cuin EU corresponds to ca. 900+ cuin US. Bottom line, Cumulus is using top-notch quality down!

The Selva 250 is 71” long, kind of a 7/8, definitively larger than typical ¾ torso-length UQs (e.g. HG Phoenix 52” or Warbonnet Yeti 46”) but somewhat smaller than full-length ones (e.g. Selva 300/450/600 available in two sizes: 85” and 93”). Selva UQs are tapered with a 43” width at head end, narrowing down to 37” at feet.

Selva design also includes shaped baffles (which gives an oval shape to the quilt when laying flat), darted ends (forming a nice taper) and 10 longitudinal overstuffed H-baffles. Selva UQs are coming with a generous draft collar on both shorter edges. Each quilt corner has a webbing loop and a LineLoc3 used for suspending the quilt (5/32” shock cord supplied with the quilt). All this gives an ergonomic 3-D type shape that fits perfectly the curvature of the hammock and its occupant. At least, that’s what I find when the quilt is paired with my 10’ Warbonnet Blackbird or 11’ Dutch Half-Zipped hammock. Also, Selva UQ construction makes that down doesn’t migrate within the baffles. I never experienced cold spots. The head and foot ends seal nicely. So far, my first Selva 250 kept me warmed and cosy down to 23 °F. I didn’t try it yet in tougher conditions. It is coming!
Selva UQs do not have a side channel. I never found it to be an issue. Side channel aficionados might want to thread a shock cord through the four grosgrain loops and use it to help hold up the underquilt. I am not sure it would bring any additional value though. Instead, I think it might interfere with the asymmetric lay and create unnecessary lateral pressure. Just me speaking.

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Moving to the customized features, I ordered 1.8 oz of overstuff (+20%, for a total fill weight of 10.6 oz). The idea was to beef-up the temperature rating and further mitigate the risk of down migration. I also ordered water-resistant down. Since there are supporters and opponents (at least in Europe), Cumulus offers it as an option. When I hold the quilt to the light, the baffles look uniformly and fully filled with a nice and fluffy down, no empty spots, no clumps.

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I replaced the thick shock cord by a standard 1/8”, which saved a pitifully small 0.7 oz. Oh, well… Finally, I asked to get the fabric Pertrex Quantum DWR 0.80 oz/sq yard (regular Selva 250) replaced with the glitzy Toray Airstatic DWR 0.56 oz/sq yard (7 deniers). Cumulus is using this fabric for their ultralight X-lite sleeping bags and some down vests. With the Toray Airtastic fabric, I roughly figured a weight saving of 1.1-1.4 oz. Huh…you are right…I guess I am a gram weenie. Mister tummy, wait your turn!

Hopefully it’ is not all about weight saving. Toray Airtastic is reported to provide efficient wind protection while being breathable (not sure where is the trick but it works; no feedback of condensation or anything). It is used by a couple of vendors for making wind jackets (e.g. Scott). The air permeability of fabrics is measured at a given air speed and pressure (Frazier type test, ASTM D737) with the data typically reported as CFM (cubic feet of air passing through a square foot of fabric per minute). A value ≤1 is windproof, 3-10 is very wind resistant, and 10-20 is wind resistant. Argon 67 and 90 (outer shell of Hammock Gear and Loco Libre underquilts) rate at 48.9 and 40.1 CFM, respectively. Pertrex Quantum rates at ca. 3-5 CFM while Airtastic is as low as 0.18 CFM (i.e. 0.09 cm3/cm2/sec); windproof!

The air resistance of Toray Airtastic is very tangible. When the underquilt is compressed for packing, it balloons up. Expelling the air is more arduous than with other quilts. Not an issue but the confirmation of its air tightness instead.

My understanding is that windchill and convective heat lost need to be factored in when discussing bottom insulation. At 25 °F air temperature, a 10 mph wind drops the windchill temperature down to 15°F. In normal circumstances, this is not an issue as the tarp cuts down on drafts (especially true for tarps with doors). Not speaking of quilt protectors or a hammock socks used for the very gusty conditions. The austere protection offered by the D.A.R.T. and my lightweight frenzy prompted me to look for another option and to give a try to a windproof underquilt. Thus, the choice of Toray Airtastic as outer shell. Wind resistance is usually coming together with a better downproofness, which cannot hurt. While I was messing-up with the quilt, I never got any down material poking out through the fabric. On the other hand, Cumulus down is of very high quality and doesn’t contain feathers or hard quills, which are the ones more prone to escape.

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I did not want this review to look too rosy and I worked hard to find defects. The only flaw I could find is the cord lock that doesn't hold tight enough the drawcord of the draft collars. Something Cumulus can easily fix.

The final weight of my underquilt is 16.4 oz (+1.1 oz for the suspension system). Compared to the other UQs with the same size, fill and temperature rating (20°F), the customized Selva 250 runs lighter. This is the result of the outer shell fabric (e.g. Hammock Gear and Loco Libre are using Argon 0.90 or 0.67 oz/sq yard), the simplified suspension system (no side channel; no shock cord along the whole UQ perimeter), and the tapered design that keeps the total surface minimal.

Selva 250 (customized); 71”x43/37"; fill: 10.6 oz 900 cuin; total weight: 16.4 oz
Loco Libre Habanero; 70”x44” 13.0 oz; 900 cuin; 21.7 oz
UGQ Zeppelin 7/8; 66”x44”; 11.9 oz 850 cuin; 20.4 oz
HG Incubator short; 73”x44"; 11.0 oz 850 cuin; 20.2 oz
HG Incubator short; 73”x44”; 10.1 oz 950 cuin; 19.3 oz
Wilderness Logics Premium winter; 72”x45/48/42”; 11.0 oz 900 cuin; 21.9 oz
(* US fill power rating)

If everything lines up, my new underquilt should give me one of the best insulation/weight/wind protection ratios. Field test very soon! A daring expedition in my backyard already convinced me that my new Selva 250 UQ (17.5 oz w/ suspension and microcarabiners) and the D.A.R.T. (4.9 oz w/ continuous ridgeline and self-tensioning guylines) look nice over the 10’ WBB. I guess I should be now hunting for a lighter hammock….maybe.

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I do not want to sound pompous or anything but some thoughts came to my mind while I was preparing this review. I was wondering whether my desperate need to write a whole book about a blanket was making sense and/or was of any use. Dunno, but it was good fun! I am a newbie and I might be missing something but I found strange that fabric specs are not discussed that much (beyond oz/sq yard and mm H2O). Are we not interested to hear about tear strength, breathability and/or wind resistance? I also found funny that fabric makers and gear manufacturers are rather reluctant to share these specs. Why? Cumulus is somewhat the exception; they were very blunt about their stuff. Also, is there a reason why underquilts/topquilts are not tested for EN 13537 temperature rating (the standardized procedure currently applied to sleeping bags)? Is it because it would be too costly for the cottage vendors?

For info, I purchased all my Cumulus gears with my own funds and the present post expresses my own independent views.