FF, Et al,
If you are asking the rating estimate for top bag use in a hammock.... A normal full bag used as a quilt, with adequate insulation below you, will do better than its rating.......
Consider this... center of the shoulder to center of the shoulder you are 30-32 inches wide.... Your bottom wrap takes care of bottom and sides well passed center shoulder.... A regular bag opened is 62-66 inches wide.... you only need 4-5 inches to tuck in on each side.... therefore you have 52-56 inches of bag to cover 30-32 inches of you..... So you lay it loosely as to almost accordian the excess and you now have 150-200 % ore lofted bag abve you....better performance.
Note to all.... When cold folk start pulling the bag / quilt closed to eliminate any air space.... so far, so good.....HOWEVER, most end up snugging the bag/quilt too far, effectively reducing loft...not good...Think about it, there is a design requirement for a certain degree of looseness to allow the insulation to reach full loft, for max effectiveness.... the ground dwellers further exaccerbate the problem by moving around, changing positions and poking a knee, elbow, shoulder, foot etc into the tightly drawn material creating a thin spot .... then there is rapid cold invasion....( not unlike the hammock bottom/side issues.
There really are a lot of ways to incorrectly use a sleeping bag/quilt... Another is to continue using a 3/4 light weight summer pad and expect to be warm because you swithed to a 10-20 degree bag...cold feet and legs will defeat this plan....
Warm is as much a thinking game as anything.... When not comfortable the first thoughts should be where is the cold coming from, why, what can one do to eliminate the problem... then what can you do to add more capability/insulation.... for example if your feet are cold... and you already have on a warm pair if socks ... and you are using the summer pad as in the above example you will be better off putting extra socks or shirt/jacket under your feet than on them ( which BTW is often is a double wammyfor reduction of circulation, as well).
So in the end.... The real issue is what is the loft between the ears.
Ounces to Grams.
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