Questions for Syntehtic Over quiltbag users

I got the MLD 48 F spirit quilt, sized extra large. It weighs 13 oz and fits well over a 0F quilt. I would use this combo down to -20F (but was doing that with the 0F quilt before getting the overbag anyway).

I also use it with a 20 F quilt down to about 5 F.

Cheers Ike,

Sound like it adds 15f-20f or so, I have an Enlightened Equipment Prodigy 50f for use as an overquilt, its long/wide and comes in at just under 14oz.

So from what you say its well worth carrying the extra weight.

Anyone else using one?

Stephen,

The over bag/quilt rating estimation I use is roughly incremental; there is no sacrificial item. There is an ~ .6 iclo from the original bag/quilt's boundary layer which is eliminated by an over bag/quilt.

I use a winter system that starts with my shoulder season 25F rated MB SS #2 in combination with a TR Xtreme sleeping pad. To adapt it to a subzero F winter season system, I overlay it with an EE Prodigy 40F quilt (6' wide @ 20 oz.).

The Prodigy's 4 oz x .82 clo/oz insulation provides ~3.44 clo. I add this value to the clo for a EN 13537 25F comfort rating, or 6.39 clo. I then reduce this total by .6 clo because the sleeping bags boundary layer is now eliminated; this yields a total system clo of 9.23. Using the EN 13537 algorithms, 9.23 clo equates to a Lower Limit Comfort rating of ~-4F.

A quilt or MB SS bag provides a variable girth system which allows you to further extend your insulation system by wearing your winter clothing insulation with minimal constriction.

Hi Richard,

Thanks very much for posting.

I use a much simpler none math (well I use the + Once ) or science method of estimation. In this case the end result is very similar actually.

I add the loft of the 2 or the equivalent down loft. If I built a 25* it would be 2.25" loft (.25" per 5*) my 40* down has 1.5" loft (prodigy is synthetic but has same rating as the down one so I use the down loft to keep it simple). Add those for 3.75". My 0* is 3.5" so I'd call this -5* which is within 1* of Richards much more intelligent approach.

You'll find .25"=5* throughout my ratings and the feedback I get is my ratings are accurate or a little conservative. Of course my quilts have come overstuffed up until the Enigma

-Tim

What do people wear inside your quilts to achieve that temperature? Base layer? An insulated jacket or vest made with synthetic or down?

Hi Tim,

That's the same rough method I was using, I sleep cold if I have bit been out for a month or more so need to be more conservative with the rating, I mentioned I was going to use the overquilt this weekend with a 3 seaon bag but wimped out at the last minute and packed my winter bag instead.

Hi Jerry,

I normally just wear base layers.

I'm typically thinking light base layer as that's what I do but really cloths aren't factored in.

-Tim