May 2, 2006 at 10:51 pm #1218481
Carol CrookerBPL Member
@cmcrookerLocale: Desert Southwest, USA
Companion thread to:May 3, 2006 at 6:35 am #1355799
John S.BPL Member
I was surprised to see that RAB’s elite top bag had the highest loft/weight ratio.May 3, 2006 at 1:47 pm #1355821
From your article, a quilt and Vapour (non-waterproof top) bivi bag would seem the best compromise: I have an (untried) suggestion— by sewing 4 tapes to the bivi bag near its top corners and similarly sewing tapes to the quilt (but (in both cases) in from the edges to allow it to drape), this could allow the user to roll about a bit more securely. A small zip at the foot end would be needed.
Also, I was surprised by the TopBag ratings: surely a top bag with more top looser outer shell is very similar to the quilt/bag system.May 4, 2006 at 5:45 pm #1355905
Donald JohnstonBPL Member
This is a very good article. Some of this is so fresh it has never been discussed in print that I know of. The explanation of how conventional and unconventional systems are used including rotating inside of an unconventional sleep system was especially well done.
1) I think an important point was overlooked when it comes to calculating weight savings with some quilt based sleep systems.
My experience with a gear list based on quilt sleep Systems in recent years is that you do save weight and gain a lot of flexibility and comfort for wider ranging conditions over a typical mummy bag based gear list.
While active in camp I need to be warm while relatively inactive collecting water, cooking and eating so I need sufficient clothing insulation for the conditions just as I would need if using a mummy bag. Combining this into my sleep system allows me to carry lighter weight dedicated sleeping gear that adds only the amount of extra insulation I need for sleeping. That is hard to do with most mummy bags because they do not have the internal girth needed for this and are not adjustable for varying amounts of additional insulated clothing. I use Arc type quilts which have the girth to accommodate my insulated clothing without compressing loft.
On a recent trip, one night I was very much too warm and my quilt enables me to sleep cooler on a warmer night by running the straps over the top of the quilt and adjusting them to provide a constant small gap of ventilation to keep me from overheating. The next night we were higher up and it was much colder. I strapped the quilt to my pad to seal out drafts. The first night I did not wear my down balaclava as the hood for my quilt the second night I did wear it as the hood for my quilt. I also wore the down balaclava in camp with my jacket achieving dual use. Neither night did I need to wear clothing insulation inside the quilt. Had temps gone down another 10 degrees I would have worn my jacket inside the quilt. The weight savings over the 25º down mummy I would have brought if I didn’t have this unconventional sleep system is 6 to 10 oz depending on which of my two quilts I had brought. Turns out I should have brought the lighter quilt on this trip but my clothing insulation would not have been changed.
2) I also think “drafts” in the context of Unconventional Sleep systems needs defining and discussion. We normally think of drafts as being steady or ongoing air movement and not easily controllable. In sleep systems I think we are really talking about two separate things – air infiltration and thermal cold spots. Air infiltration is outside air moving inside. Thermal Cold spots result from lack of or insufficient insulation between you and outside air with at least one layer of fabric between. Air infiltration is typically transient in well designed products.
A bivy used with a quilt or top bag serves only to reduce air infiltration should the quilt or top bag not manage that sufficiently well on its own. A bivy does not help with cold spots. Thermal cold spots will result when an un-insulated area of fabric is between you and outside air as could occur with a quilt in a bivy sack or a top bag when the insulated area is lifted off your ground insulation. Prevention of cold spots should be addressed in the design of the quilt or top bag. With some quilts air infiltration is part of an intentional design to be used and managed for increasing comfort when desired and eliminated when it is undesirable.
Quilts are intended to be more flexible than a mummy bag. With a well designed quilt such as an Arc Alpinist features are provided to enable you to control air infiltration providing it when you want it, restricting it when you don’t and head insulation is optional. With the quilt simply draped over you it performs much like a conventional mummy bag opened up and draped over you. If it drapes well it conforms to the body and when you are not moving Air infiltration is sealed out by the lengths of excess down to either side of you. At the neck you can draw the material close to seal to the extent desired but you will have brief air infiltration as you move around in the night and that may be desirable in warmer conditions. When that arrangement is too hot with this quilt you can use the straps to create air infiltration to varying degrees by running them over the top of the quilt and adjusting them to lift the edges of the quilt to break the natural seal to the desired extent. In colder conditions when you don’t want air infiltration but you still want freedom to move around in your sleep you can strap the quilt to your pad and draw the neck cord. Air infiltration is well controlled at this point. Add a down balaclava and draw the quilts neck cord to seal to it and you can turn in your sleep without breathing into a hood. Your body weight is sealing the quilt to the pad in the areas above and below the straps. To create air infiltration at this point you have to lift you upper body or you lower body below the straps off the pad or grab the lower quilt and twist it around enough to expose the open bottom. When it is cold enough to approach the thermal limits of the quilts loft you can trade interior space and freedom of movement for maximum thermal efficiency by minimize excess girth. Run the quilt straps over the pad, under your body and adjust them for a close fit. Stay on your back to stay sealed to your pad.
I rotate inside my quilt, sleep on either side and draw a leg or two up inside my quilt. When I rotate I rotate inside without pulling on the quilt so the quilt does not follow me and stays sealed to the pad unless I have the neck cord drawn. If it is cold and I have the neck cord drawn I will need to un-rotate the neck area which I do unconsciously with a slight tug. I do not have any problem at all with air infiltration unless I raise my upper body excessively breaking the seal under my neck that is normally sealed by my makeshift pillow. On warm nights this is desirable and a cooling tool I use. If designing my quilt again I would make a small change to insulate a small additional area near and under the neck when the quilt is closed at the neck.
3) While they work together to provide a comfortable nights sleep I consider my sleeping insulation system and my shelter system to be separate systems and a bivy is a part of the shelter system. If I bring a tent I don’t bring a bivy. If I bring a tarp a bivy is substituting for tent features absent in a tarp. To me a bivy is part of the shelter system and while taken into consideration when making a gear list it is not a significant factor in deciding on my choice of sleeping insulation. I have rarely used a bivy with my quilt and I sleep mostly in open AT style shelters, or floorless tarp shelters exposed to light wind. Only in conditions where I need more protection from strong wind or blown moisture do I use a bivy or a tent.May 4, 2006 at 9:38 pm #1355923
Last winter I made an observation that seems so simple that I’m surprised no one else has made mention of it before.
Due to various factors one evening I ended up with a very wet down mummy bag. I’m one of those people who rolls over on a regular basis and due to the weight of the sodden down found it easier to rotate inside the bag instead of my normal pattern of rotating the bag with my body. After several hours I observed increased loft in the stationary upper portion of my bag.
I believe this is because the stationary portion of down above my body had constant body heat to drive much of the moisture out. If the bag was rotated normally ones rising body heat would have been distributed to a larger portion of damp down for shorter periods of time resulting in less drying of the most important portion above ones body.
It seems to me that the stable heat path created by the stationary insulation in quilts and top bag designs should move the dew point closer to the exterior shell than a regularly rotated mummy bag.
So, with the exception of the night mentioned above, am I all wet?
RobertMay 8, 2006 at 3:51 am #1356073
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
I am puzzled by the blind spot in the definition of a quilt. It seems that it is assumed that a quilt will have no hood. But WHY? It makes NO sense.
I make a lot of my own gear. My light sleeping bag has 300 g of 800 loft down in 250 g Pertex microlight shell (with 3/4 length zip). This SB, with standard thermals, a good air mat and a tent, is just adequate down to freezing point. I cheat a bit when it’s that cold: I snuggle up to my wife in our tent. Believe me, this helps!
But for the last year I have been using the bag as a quilt with great success.The closed foot box keeps everything under control at the lower end. The HOOD, yes, HOOD, goes over my head. All this worry about draft channels disappears: the hood blocks any drafts, and keeps the upper half under control. And I have acres of space to wriggle around, UNDER the quilt.
From physiology PoV, your head is the most crucial part of your body. Your body will keep your head warm even if that means your feet get frostbite. So why in hell’s name should you cut the hood off a quilt designed for use in winter? It simply does not make sense!
For even colder conditions (recently) we took these bags and a lighter summer quilt with only 150 g of 650 loft down with us. We drew the extra bag over the top of our two SBs. We also had ‘ski hats’ of 200-weight fleece on our heads. We were *warm* at -5 C, under the double quilts.
I think SB design has a long way to go yet, and it needs a bit more engineering/physiology input. Some current fashions, like cutting the hood off, have got to die.May 8, 2006 at 5:34 am #1356076
@pjLocale: LazyBoy in my Den - miss the forest
Recently, I was experimenting with using a mummy bag in “quilt” mode. The “footbox” was zippered up to the level of the rear of the knee joint. This worked precisely as you stated to “keep everything under control at the lower end”.
At the upper end, tucking the right zip bag just a bit under my left shoulder allowed the hood to be used in a manner nearly identical to how it would be deployed when totally zipped up in mummy bag mode. After donning the hood, i was further able to tuck the right side under my right shoulder and obtained a pretty good seal around the neck and shoulders. So, my personal experience agrees with your own observations.
Now, in my case, i was using a short-length mummy bag, but still had a few inches to play with. I was able to get the hood to “dress” nicely and evenly on both sides of my head and face. Perhaps if someone were at the maximum size limit for a particular mummy bag, it might be a bit more difficult to get the hood to dress evenly on both sides of their face?
Personally, other than on warm-to-hot summer nights, i still prefer a tightly zipped and sealed mummy bag, but i believe that you are absolutely correct that a quilt does not necessarily obviate the need or usefulness of an attached hood.
Others may rightly cite the dual-use aspect of a separate down hood or balaclava as serving a purpose similar to an attached hood, yet still have utility for around camp use when necessary.
Anyways, not that your observations require such, but i thought that i would just post and validate your observations.May 8, 2006 at 5:41 am #1356077
Benjamin SmithBPL Member
@bugbombLocale: South Texas
I think it depends – are we talking about a light summer quilt, as you were when you started, or a “quilt designed for use in winter”? For a light summer quilt – and I think that very few of the folks in this thread are contemplating a quilt for subzero temps, though I’m sure some are – the warm headgear you bring with you should be enough. In keeping with the ultralight ethos, I’d plan on bringing a warm, hooded parka on a colder trip, and could just wear that inside the bag/quilt with the hood on. No one is saying that hoods don’t work, or that head warmth isn’t important – we’re saying that a sleeping bag hood isn’t the most weight-efficient way to achieve that level of warmth.
BenMay 8, 2006 at 7:11 am #1356080
@peter_panLocale: Co-Owner Jacks 'R' Better, LLC, VA
This is a good article to start the thinking…However, it does seems like it is focused on mummyesk solutions. The presentation is almost entirely on the top bag style and wearable systems that retain the mummy approach…
While this is enlightening,it misses the versitility of the true quilt approach…Additionally, there are true quilts that are wearable, most notably the Jacksrbetter No Sniveller and the JRB Stealth models…. These top quality 800+ pf models easily cover three season and summer applications and are as light as 15 oz…Notably, there is a JRB Down Hood which integrates to the resealable head hole or can be used alone with any hoodless bag or quilt…at 2 oz this hood is twice as light as any other down hood or balaclava available.
While this article does not discuss the design principle of these serape or poncho like quilts it is noted that a companion article is in the making…Hopefully, it will broaden both the design perameters to include these available designs and the breath of manufactures producing quality wearable quilts/alternative sleeping systems.
It is noteworthy that in the staff vinettes of gear at the end of this theoretical article 33percent are using JRB quilts.
Looking forward to broadening alternative approaches and a companion article with a wider market survey.
JRB Co-OwnerMay 10, 2006 at 2:37 pm #1356193
Michael MartinBPL Member
@mikemartinLocale: North Idaho
>> Not enough weight was put on loft:weight raio when that heavy arse frog sac got a higher overall rating that the quantum top bag.
The $99 MSRP Frog Sac achieved the highest “Value” score of any bag tested, contributing to its overall rank. For hikers looking for the absolute best equipment where price is no object, please take a look at the “Subtotal” column in the chart.
-MikeMay 10, 2006 at 4:56 pm #1356204
Donald JohnstonBPL Member
“It seems that it is assumed that a quilt will have no hood. But WHY? It makes NO sense.”
There probably is a market for one with an attached hood.
For my quilt the reasons were intended use as well as practicalities. You could permanently attach a hood to the top or side of a quilt but it would probably be in the way when it is too warm and adds un-needed weight in warmer weather where a hood is simply too warm. Does a hood really need to be attached? A hood could be made that is removable yet attaches in a fixed position but you loose the ability to roll from side to side without breathing into the hood. An optional hood/Balaclava is pretty much where we are now where you skip the hood in warmer weather and bring a hood that provides the appropriate amount of additional insulation for cooler conditions. The head outside of a hood helps with comfort on a too warm night. I think quilts so far have been designed to work well in the warmer months and extended into colder conditions by adding options such as a hood or clothing and straps. There probably is a market for a quilt designed for cold weather that incorporates an attached hood. For me camping at varying elevations in warmer months, being too hot is frequently an issue yet there are colder nights at elevation where I need more warmth on the same trip. No hood and a vented quilt works down low and battening down the hatches works up higher. If I need any head insulation at all my sun hat, jacket or a thin fabric balaclava will do. I can decide what level of head insulation to bring before the trip. A much thinner quilt with a very thin hood might work for the warmer nights but when you go higher and colder you still need more insulation and your options are now pretty much limited to wearing extra clothes. Clothes tend to have a lower warmth to weight ratio but the system should work fine. I have not brought a hood on my summer trips and saved those few ounces while retaining the possibility of using other gear to create make shift head warmth in the event of unplanned for cold. I haven’t need to do that so far. Outside of summer I bring a hood.May 12, 2006 at 1:48 am #1356273
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
Perhaps I had better explain a bit more what my hood looks like and how I use it in the cold. I am not sure the word ‘hood’ means the same thing to everyone.
Imaging a quilt with the bottom sewn together for a foot box, or a single tapered hoodless bag with a 3/4 length zip. Now add a generous semi-circular extension to the top end in the middle. This is my hood. It can be opened out flat: there are no fancies in the design. I made these two bags (wife and me) myself – quite easy to do.
In the cold, I snuggle down into the bag (which is long enough!) and throw the hood right over the top of my head. The edge of the hood does actually touch the ground or my mat all the way around. I usually pull it back from face a bit if I am warm enough. In addition, the sides flop down on either side of my air mat: the quilt is not so narrrow that I am struggling to get a ground seal. If it’s real cold, the breathing gap may collapse for a while, but this doesn’t worry me. Enough oxygen diffuses in for me. My wife likes to wear a fleece cap/hood as well, but she doesn’t like the hood over her head so much.
But this means that there are no gaps around my body and head for drafts. So if the lay of the quilt over my body is a bit loose, this doesn’t matter. The air inside warms up real quick – especially if am breathing out under the bag. So-called ‘dead’ air does not matter!
This does require that the bag be not absolutely minimal in dimensions. True. It would be a little lighter if I made it shorter and narrower. But the savings would not be that great, while the potential for drafts and loss of warmth would be high. But the benefits of the generous size are enormous flexibility and comfort. I can sleep in any position I choose.
In hot weather I can simply push the bag downwards, off my head and shoulders, and let some drafts in. If it is a really hot Australian summer night, I may actually sleep on top of my mat without the bag above my knees – this has happened!
Sure, it would be nice to have lots of bags with a fine gradation of performance, but most of us lack the dollars and the storage space. (Don’t forget the latter!) So a bag which can go from 30 F to 100 F isn’t bad value.
As it is, this bag has taken me down to freezing with me wearing thermals, and to -5 C (23 F) with a very light quilt over the top. But I do sleep next to my wife! You should never underestimate the value of having a warm sleeping partner. But I hesitate to include this under ‘unconventional sleep systems’!
250 g Pertex microlight shell 8.8 oz
300 g of 800 loft down 10.6 oz
That’s 550 g total 19.4 oz
Spare quilt 150 g of down 5.3 oz (shell not included – cheap and heavy)
My (our) current thinking is to keep these bags for winter snow trips by adding a UL quilt with about 300 g of 800 loft down to go over the two of us. A bit of a single-layer foot box at the bottom to go under our feet, and maybe something at the top corners to control the top end. Maybe a bit of string to tie to some other gear – movable rather than fixed under the mat?
CheersMay 14, 2006 at 8:21 am #1356366
Thanks for this series of articles, it was well put together and very refreshing to have a subject dealt with on more than just one level and more than just one time. So many times we get just a little discussion on a subject before the article ends and then are forced to rely on a talk group format to get any more discussion and many times all we recieve is personal “opinion” and not facts that are the result of investigation or just plain old use. Personally I am a warm sleeper and like to toss and turn when sleeping, so I have found more to my liking to use Semi-rectangular bags and turn inside the bag instead of rolling around with the bag. And I have definetely found that when you roll off the sleeping pad that your body knows it and you either wake up or continue to sleep in a uncomfortable fashion, which can lead to loss of sleep and results in less than peak performance both mentally and physically.
I think that many of the ventilation problems of top bags are not problems but instead a welcome relief for anyone that sleeps “warm”.
I have tried many sleep systems and gone through many bags in the past, but I now use the Big Agnes system and have never slept better. If comfortable sleep is so important to restoring energy to the body then it is my luxury item and I will do whatever it takes to be able to recover from a hard day at work on the trail.
When Big Agnes came out with thier sleep system it made and still does make perfect sense. It is nice to see a small company take on the big boys with a better idea and let the consumer that actually uses the product (instead of just reading about it and giving lip service) the benefit.
The chance to sleep in comfort and truly derive benefit from it is welcomed anytime.
RexMay 14, 2006 at 11:47 am #1356381
An article on the nature/principle of insulation would be good (I couldn’t find any):
How well contained does air need to be to be viewed as ‘still’ , what is the optimum size of air pocket etc.
Polyester wadding seems pretty open, so how come it doesnt lose heat via convective air currents whereas a similarair gap between two shell fabrics would?
Also, as Down has the large flaw of losing insulation when wet (can’t this be fixed, after all it comes from waterfowl), I wondered why there are no polyester ‘sythetic copies’ of down clusters, as presumably the structure
is what gives it such a high loft to weight/compressibility ratio.
Would any hikers be interested in high loft loop pile coarse fleece for simple quilts:
needing no shell fabric (just an outer unproofed windproof bivi) would be robust, easy to wash, easily layered etc. I think Malden Mills tryed some for garments but testers thought was to coarse but wouldnt it be OK for blankets?May 14, 2006 at 12:38 pm #1356383
Richard NisleyBPL Member
@richard295Locale: San Francisco Bay Area
There is a boundary layer out to 6 mm from the insulation fiber that is “still” or a boundary layer between two fibers of up to 12 mm.
The tangled nature of the polyester wadding provides the necessary boundary layer distances.
Synthetic down is a patented product which has the trademark of Primaloft One. It is very close to the weight/compressibility ratio of down. It is prohibitively expensive for use in sleeping bags and it “doesn’t look warm because it isn’t very thick for a given temperature rating” based on mass market consumer studies.
The clo/oz ratio of fleece is prohibitively poor. Polartec 300 (the thickest common fleece) only provides about .25” of loft and you need a minimum of 2” for sleeping in 20F temps.
Explaining how insulation works is a relatively complicated subject. I doubt if most of the readers would want to wade through the level of detail it takes to understand it.May 14, 2006 at 1:37 pm #1356384
@ericlLocale: Northern Colorado
I’ve not posted here before, but I’ve have been experimenting with ultralight for the past ten years, having started backpacking in the early 70s.
I presently use a Feathered Friends Wren II (winter wren) as my only 3-season warm insulation. As Ryan mentioned, the loose fit, especially midway, detracts somewhat from its overall efficiency, but the concept works.
Why take even a relatively thin bag if its only use is for sleeping? Why wouldn’t the more ideal ultralight approach be either a wearable bag or sleepable clothing? Having personally struck out on sleepable clothing, I find the wearable bag worthy of more development. Surely, one could rig up one’s pack to create quick access to use the bag as a rest stop parka.
I am a big fan of vapor barriers, starting with Stephenson’s original no sweat shirt in the 70s. VBs have worked for me in temperatures as high as the low 40s. I couldn’t help but think that Glen, Alan, and Ryan, could have used ultralight VB to good effect for their Wyoming trip when temps fell to 15 degrees.
My latest rig uses one of Glen’s ultralight plastic cloths taped up to make a waterproof bivy, used with vapor barrier clothes or sack. Total extra weight is under 3 ounces, including a VB ‘shirt’ I can wear. This gives me a waterproof/draftproof bag and less heat lost to insensible sweat evaporation. Very little moisture through the bag should mean less lost loft and better bag life. (I do assume the VB causes some heat loss due to the increased conductivity of moist air next to my skin.) I’ve used this same method of VB/insulation/VB on my hands and feet for many years to good effect.May 14, 2006 at 2:03 pm #1356385
Bill FornshellBPL Member
@bfornshellLocale: Southern Texas
I have some
that I bought about 2 years ago on sale from Thai Silks. It is still listed on the site. The price however is now $25.80 a yard. The color I have is called “Cranberry”. It is a very nice.
I have never used it and now wonder how warm it might be as a cover of some type. If S. Texas gets any cool weather again I will get it out and sleep under it and see how it works.
It is listed as:
It comes 55″ wide and I have 3 yards. My guess is that it is between 3 and 5mm thick. I have 2mm neoprene and it is thicker than that.May 14, 2006 at 6:27 pm #1356392
@vickrhinesLocale: Central Texas
Don’t worry your little head about throwing a “relatively complicated subject” at the readers here. A more eclectic and geekier gaggle of techno nerds would be hard to find.
If insulation were not complicated, we wouldn’t still primarily be using goose down for backpacker’s snuggies. Yes, the boundary layer is the operant insulator in fibrous materials, just as air micro-encapsulated in low-conductivity materials such as polyethelene is the operant insulator in foam sleeping pads. And so on. What we don’t really have is a reliable system for comparing the virtues of different insulators under realistic field conditions.
I agree with you about fleece.May 14, 2006 at 6:54 pm #1356393
Michael MartinBPL Member
@mikemartinLocale: North Idaho
>> What we don’t really have is a reliable system for comparing the virtues of different insulators under realistic field conditions.
Stay tuned, Guys. I’m working on an article comparing and testing the characteristics of (currently) six different sleeping bag insulations. It’s on the Editorial Calendar for publication this fall.
A bit off topic, but you might also want to peek at the Bag Rating Position Statement. We quietly updated it recently with some loft/warmth guidelines.
-MikeMay 14, 2006 at 6:55 pm #1356394
@slowhikeLocale: South East U.S.
this past winter i made a quilt that extends up past my head & has a slit for the head to poke through. this slit has an insulated collar about 4″ long that loosely lays around the neck
when needed, it can be gently snuged up around the neck to close off the cold/hot air exchange.
i really don`t like the feeling of any thing “tight” around my neck, so the way i made the collar is w/ a channel for a very small, light weight elastic cord on the “outside” of the insulated collar. so when i pull the elastic cord through the micro cord-lock, it very gently draws the insulation around my neck, sealing in heat, w/o feeling restricted.
the extra portion of the quilt just lays under my head & drapes around my shoulders. very efficient.
i sleep in a hammock so the quilt works great for me!
when i roll, my neck turns freely in the lightly compressed collar… even if i`m wearing a seperate hood of some kind.
i got the basic idea for this from the “jacks are better” no sneveler. i haven`t seen there quilt in person to see just how there collar is made around the head-hole, but mabey i can take a look at it if they are going to be at “trail days” in damascus, va, this year (may 19-21).
i realy like that basic idea of the head-hole w/ adjustable insulation around the neck.
i also like there down sleves & hood!
i`m planing to make another quilt much like the one i described, but w/ a little extra width to pull it around me & wear around camp when needed. …timMay 14, 2006 at 7:04 pm #1356395
@peter_panLocale: Co-Owner Jacks 'R' Better, LLC, VA
JRB will be vending at Trail Days (Fri and Sat)…Please stop and introduce yourself and demo the No Sniveller quilt….sleeve and hood too, while you are at it.
PanMay 15, 2006 at 12:30 pm #1356421
Fleece/Pile has the useful property of having a string enough structure not to need a shell fabric, so if a special high loft, open, robust, Loop Pile fleece with loft weight ratio competitive with wadding, I thought this would be useful due to robustness, ease of washing, easy choice of number of layers.
I dont think feeling coarser than clothing fleece would matter.
The fact that washing is bad for wadding seems unfortunate.May 15, 2006 at 12:32 pm #1356422
Thanks to Richard Nisley for boundary information.
(this should have been posted before last post)May 15, 2006 at 7:38 pm #1356438
First of all – great set of articles. Especially, since a JRB quilt was rated #1 overall.
But I have one question about the criteria. The loft to weight ratio bothers me. It really doesn’t seem to be a meaningful measure of anything because there is so much difference in the parameters for each quilt/bag. Different dimensions, different baffle heights, different fill (synthetic vs. down) and different fill power down.
Consider the following example. I could make a 3 foot square quilt out of 1.1 ounce ripstop nylon, baffled to 3 inches (7.62 cm), filled with 800 fill power down. Roughly speaking the ripstop would weigh 2.2 ounces (62.37 grams). Two square yards times 1.1 ounces per square yard. And the Down filling (no overstuff) would weigh 4.86 ounces (137.78 grams). 36” x 36” x 3” divided by 800. Disregarding the weight of the baffles the total weight of the quilt would be on the order of 7.06 ounces (200.15 grams or 0.20015 kg). The loft to weight ratio would be 38.07. That’s huge compared to the items reviewed – but I think you’d have to agree a 3’ x 3’ quilt isn’t going to keep anybody warm. What’s the point of that measurement?
It seems to me that a straightforward weight comparison and a loft comparison are more meaningful statistics.
One other thing I found curious is the inconsistency in manufacturer temperature ratings for a particular single layer loft. This is a number I have been adamantly against establishing for JRB products because there are simply too many personal/individual variables involved. Then there’s the liability issue when some novice takes a published rating to heart and suffers hypothermia. The experienced camper should understand his/her own body (cold or warm sleeper) and sleeping style (clothes types and amount worn) and know what thickness of bag he/she needs. Less experienced campers must be encouraged to take extra precautions until they understand their boundaries and the limitations of their equipment.
Jacks ‘R’ Better, LLCMay 15, 2006 at 7:54 pm #1356439
@slowhikeLocale: South East U.S.
if nothing happens, i`ll be there sat. thanks …tim
You must be logged in to reply to this topic.