Still Warm at 17 F with Modular Sleep System

[Cuthalion]

Hello,
I just purchased my first Hammock a couple months ago, and have been trying to get out camping as much as possible. However, its getting colder here in Maine, and I am still waiting to get cold in my hammock.

I do not have a tarp. I do not have quilts.

All I use is a Therma-rest mat between the layers of my WBBB DBL 1.7, and a USMC modular sleep system with goretex bivy. I have camped as low as 17 F, and wake-up uncomfortably warm, though not sweating.

The upside to the modular sleep system is of course that it is modular. You can use different sleep bag combinations based on the conditions. Secondly is price (compared to purchasing more than one sleeping bag...or quilt(s)).

The modular system when combined is waterproof and rated at -40 F. The two individual bags are rated above 30 F, and 10-30 F. When I do not use the combined system, I use the extra sleeping bag as padding/insulation beneath me.

The downside is the size and weight, though I do not know the difference in weight versus carrying a top-quilt and under-quilt. The complete modular sleep system in the compression sack is 8-10 lbs.

I am hoping to get down to 10 F with this set-up, but am not holding my breath. I should also add that I have been fortunate not to have encountered high wind (so I just picked up a Superfly).

[wisenber]

I've looked into the military component stuff before. I noticed that the military temperature rating system differed from the commercial rating system in a notable way. The civilian ratings are for remaining comfortable with normal amounts of camp sleeping clothing for a night. The military system is rated for "surviving for four hours while wearing field gear". That might make the military -40 closer to a civilian -10 degree.
I checked the weights for the four part system including bivy. It was showing 12.5 pounds. Throw in the thermarest, and you're getting close to 14 pounds.
If that works for you, that's great.

In contrast, my 20 degree peapod, 3 season Phoenix and No Sniveler can manage -15 F comfortably and weigh around 4.75 lbs. That would have you carrying about 9 lbs more for around the same temp rating. Both systems are bulky though. If you want to get below 0 F, there aren't many ways to avoid it that I know.

[Dos]

I checked the weights for the four part system including bivy.

do you have a break down of each part by any chance?

[wisenber]

do you have a break down of each part by any chance?

There is no break down by component. It just had the total weight for the system along with the dimensions of each of the parts (bivy, int. bag and patrol bag).
I got my info here.

"When all 3 components are used together the system is rated to provide 4 hours sleep at -40°F."

[TheCoyote]

do you have a break down of each part by any chance?

Genuine US military issue Modular Sleep System (MSS).

Genuine US Army and Marine Corps standard issue MSS consists of four components for sleeping in up to -30 F temperatures:
Goretex BIVY outer cover bag 60 F (1.5 lbs)
Patrol Sleeping Bag 30 to 50 F (3 lbs)
Intermediate Cold Weather Sleeping Bbag 30 to -10 F (4 lbs)
Compression Stuff Sack



Modular layering design.

Completely integrated system rated to -30 F when the user wears the expedition weight polypropylene shirt, drawers and issue cushion sole woolen socks. To obtain lower ratings, additional layers of Extreme Cold Weather Clothing articles are required.

Warmest system rated to 60 F with Goretex bivy cover as main bag and other bags as cushioning.

To obtain lower temperature ratings, additional layers of Extreme Cold Weather Clothing articles must be added to the user's clothing ensemble inside the sleeping bag.

Four component weight: 8.5 lbs

[dkperdue]

I made a "Pea-Pod" type underquilt for my son and I to use with some of the components of the MSS.
Went with just the goretex bivy sack and the patrol bag parts and he zips it up all around him in the 20's and is fine.
I use it as an UQ and have had great success as well.

Sure wish they had had it when I was in!
It would have been perfect up in the Sierra Nevadas for the Cold Weather and Mountain packages I went through.

DKPerdue

[DivaB]

We have the patrol bags and not the entire system. We absolutely love the patrol bags! They're not terribly heavy, really warm, converts into a great top quilt, and compress nicely. Earlier in the year I had made each of us polar fleece top quilts, and in the cold weather we will just shove our polar fleece into the patrol bag for added warmth. After the holidays, I plan on cutting off the zippers and hardware, which will make them even lighter. You also can't beat the price. I won ours on ebay ranging from $8 - 10 a piece.

I've often wondered how the patrol bag would work being converted to an UQ? Especially if a pad were added or our poncho liner uq added to it...if that would help us out without too much weight penalty? I'm a little unsure about this though, as they are made to really be on you and there isn't a lot of loft, so I'm not sure they would insulate as well being hung under you. May be something I play with later thought.

[Cali]

I have this same setup and was trying to figure a good way to use it, or parts of it. It is definitely too heavy all together. I thought about just the bivy and the patrol bag as a peapod style setup, as stated above. I haven't had a chance to check it out though. Maybe after the holidays.

[Psyop]

This is what Im using now as well. Ive gotten down to 24 with therma rest and using the patrol bag to lay on and the heavy bag as a top quilt. Havent gotten out the bivey bag yet. On the ground I have went to single digits with no shelter and was warm. Sure its heavy and Id like to upgrade but its a good bit of gear. The best thing is it was a gift from my Uncle

[Owl]

I'll be interested in seeing your setup, Psyop, when you come out to the KC winter hang.

I've got an old ICW sleeping bag that was also a gift from my Uncle...used it to the single digits many, many times. I'll be in my car as backup if my new-fangled lighter weight gear fails me on that trip.