Originally Posted by BillyBob58
Interesting test, FLRider! A GI is really kind of what a HHSS is a version of, although a custom fit and way more expensive version including an OCF pad that molds around your body.
Your table shows a PL as top insulation and I see no mention of bottom insulation? Did you mean the PL is the UQ? Or was it 2 PLs one for TQ another for UQ?
As for such a big dif when the temps dopped only a couple of degrees, could it be that your metabolism slowed down as you slept, plus the cumulative heat loss after 2 hours?
But, I have no idea what kind of insulation the PL has. So I don't know if cold at this temp is a good result or bad?
I would expect to be warmer than that with the HHSS's OCF pad and sil-nylon UC even with out the space blanket, though maybe with some condensation. At least I have occasionally slept at about those temps with no SSB with no problems, some times with condensation, sometimes not. And would expect to be way warmer with the SB. Do you think a PLs insulation should be comparable to an HHSS OCF pad plus UC, or would you expect it to be less?
How about fit? Was it snug enough without being too tight?
The poncho liner is the top insulation; it's good for me down into the mid-thirties before supplementation, assuming a longsleeve baselayer, shorts, puffy socks, and a watch cap (so, the only difference is the longsleeve and the hat from what I used last night; what I was wearing last night would be good down to about 40* with just the liner as a top quilt). This also presumes decent under insulation, which was what failed last night.
The under insulation was the Garlington insulator; that's all. I'd been using a sew-'em-up PLUQ over last "winter", and I find that it's good for me down to about 25* F (see here
for details) with my normal clothing and top insulation at that temp. I'm trying to shed weight as much as possible though, and the Garlington has become my summer insulation (so, anywhere from March to October down here), shedding a good pound and three-quarters or so from my pack during those months.
It's entirely possible that it was due to my metabolism and cumulative heat loss, yes. However, when I say that I was cold
, it wasn't, "I have a little chill; I could get up, walk around, warm up a bit, and go back to bed". It was, "Yeah, I'm not going to be able to sleep the rest of the night. I'm pretty freezing right now."
Which is why I did the testing in my front yard; I wanted somewhere to bail if things turned out to be colder than I'd thought. I was
expecting an uncomfortable night, since I was testing the low end of survivability with this under insulation rather than its comfort zone. However, the cold I experienced was farther out than merely uncomfortable; it was not something that I could sleep through, even fitfully.
As to the HHSS vs. a PLUQ, I'd expect that in terms of raw warmth (i.e.: no wind, no precipitation, low humidity) that a no-sew PLUQ and the SS without a space blanket would perform about the same. I'd also expect that the SS would perform better in wet, blowing weather; while the PLUQ would perform better at high humidity without precipitation or wind.
I would also expect that the HHSS with
a space blanket would perform about the same as a sewn-up PLUQ with average added insulation (I'm assuming InsulBright or a layer of IX with the proper darts here) in terms of raw warmth. The HHSS should perform better in wet, windy weather; while they should be about at a draw for high humidity, since the space blanket will act as a vapor barrier to prevent the OCF pad from becoming soaked.
As to fit, it works almost perfectly. I still need to add Demostix-inspired draft skirts to my hammock to close up the ends of the poncho (since I used OmniTape [well, the generic knockoff of it, anyway] as a closure system for the poncho, it doesn't grip quite well enough at the ends for the shock cord there to not be able to pull it away from the hammock body when I shift position)--and the ends of the modular underquilt that I'm designing. Once I do that, it should seal up nicely.
There'll be changes on the whole thing as I get time, inspiration, and funds. One thing at a time, though...