Temp rating test – Montbell UL SS Down Hugger Thermal Sheet 50F rating

[Tom Lyons]

After just having recieved my new SMD Gatewood Cape, and setting it up in the back field to seam seal it, I decided to use the opportunity to check out if my Montbell Thermal Sheet could suffice for its rating without any additional help.

The Thermal Sheet is rated in the advertisements to be good down to 50F. I have read anecdotes that it had an "optimistic" rating. I had a weather forecast yesterday that the temps would be in the low 50s at night. So, I put my "space" mylar groundsheet down, inflated my Klymit X-Lite pad, and rolled out my Montbell thermal sheet inside the Gatewood Cape. I also had an inflatable travel pillow of the horseshoe style, and I inflated that too. The fleecy fabric cover was removed from the pillow for weight reduction previously.

The Gatewood Cape was set up and re-tensioned by nightfall. BTW, I waited until about an hour after nightfall to get into the tarp, because I didn't have the bug net inner tent inside the GC. When I got in, there were essentially no bugs around. The set up was intentionally in the most condensation prone location I could find, so that I could see how the GC did for condensation when the temps dropped below dew point. It was an open grassy field with no overhead leaf coverage, and a clear crisp night, and we have had a lot of rain lately, and my field is low-lying.
I did not have a full footprint groundsheet, so the entire vestibule ground area was open under the tarp, with exposed grass for moisture to be available from the ground.

I went to sleep in the bag with just the clothes that I had worn all day, as a typical "control" setting. No special baselayers or anything. Just a pair of cotton cargo shorts and a cotton T-shirt. No socks. I did bring a women's shower cap outside with me, because the Thermal Sheet does not have any hood. It stops at the shoulders. I ended up using the shower cap to help keep my bald head warm, and it worked.

At the time I turned-in at about 10pm last night, there was already a light coat of condensation on the tarp. The pitch was tight, and nothing dripped on me all night. There was almost no wind at all, for the entire night. Very still.

So, I woke up at sunrise this morning, and it was 52 degrees F. I felt a bit chilly, but it wasn't horrible. No shivering. I think this MB Thermal Sheet is fairly rated. I am a cold sleeper, and I always like to be a little bit on the warm side. So for me, this is good performance because I get cold easier than many of you out there reading this. I wouldn't want to take this Thermal Sheet any lower in temps without some sort of heavier base layer on, or using some other form of help to keep warmer.
But I wasn't "freezing cold".
It was a good kind of chilly, in a "crisp morning" kind of way, and if I had a campfire outside or something, it would have been perfect to brew a cup of coffee and sit by the campfire to warm up and enjoy the early morning time before breaking camp.

BTW, my impression of the Gatewood Cape as a shelter was VERY good. I am accustomed to using a 5×8 flat tarp in half-mid config, and this thing was like a palace in comparison. It's basically a half-mid with a very large beak/vestibule, and it has what I consider to be full-coverage for all intents and purposes. I won't get wet in this thing, but I got wet plenty under the 5×8 tarp. The condensation with the hood tied shut and pitched about 6" off the ground was minimal. There was a light coating of condensation all over it, but nothing was dripping off. I was dry, and even though my down bag foot touched the wall a few times, it didn't wet the bag in any noticeable way.
Very easy to pitch too. Plenty of room. Can sit up. Door works good and is very nice, and can be rolled and tied open. It pitches tight, and is weathertight and stable and roomy.
I am very pleased with my purchase of the Gatewood Cape.

Regarding the Klymit Inertia X-Lite pad, this was my first night with it.
I inflated it fairly full, but I left it sort of squishy. It's not a thick pad, but it supported my 225 pounds off the ground, and if I hit the ground with my hips when side-sleeping, I didn't notice it. It was surprisingly comfortable. I'm 5'10, and I fit the pad properly, so this may have something to do with my successful use of it. But I liked it, and it was comfortable on my back and on both sides during the night, and I had no aches or pains at all when I got up. This gets a big "thumbs up" from me.
I will say that the cheap travel pillow was a God-send. I like to have my head supported, and without that travel pillow, I would not have been happy.

Overall, the gear all worked as intended, and my night out in 52 degree weather was successful and comfortable, but near the lower limits of what this Montbell Thermal Sheet can do on its own. I have no doubt that it could go into the 40s with some good warm baselayers on, to help it out. And a good warm hat or hood.
The temp didn't hit exactly 50F to test the rating, but it got very close to that, and I got a feel for what it can do near its advertised limit, and I think it's rated accurately.

Gatewood Cape = 11 ounces
Montbell Thermal Sheet Sleeping Bag = 13 ounces
Klymit X-Lite pad = 6.5 ounces
Mylar Space Groundsheet(trimmed) = 1.5 ounces

Total weight of overnight gear = 32 ounces(2 pounds total)

Add in my GG RikSak pack at 2.3 ounces, and you have my Base Weight at 34.5 ounces.
Just over 2 pounds Base Weight.

[Adam Kramer]

good stuff. thanks for sharing. maybe put that in a review on the review section for the thermal sheet.

[Nick G]

Thanks a lot for the review–I'm considering a purchase of the Gatewood Cape, and this helped me move forwards towards getting it. I've heard that the shelter design makes it not as good when used as a poncho–is this your experience as well?

I fit the Klymit X-lite as well, and I'm 6'2". I suspect whether you fit the pad has much more to do with Torso size than overall height–perhaps we'd better start doing some research as to what torso lengths fit the pad?

I'm an 18.5" torso, and the X-lite fits me perfectly. I sleep on it primarily on my back, but have no problem on my side either. I have recently acquired an X-frame, and it fits me as well (although I haven't slept in it yet).

If anyone else has tried the x-lite, I'd be curious to know what torso lengths definitely fit the pad and which ones do not.

By the way, that is one impressively light sleep system–the only way I can imagine going lighter would be to switch to the Golite poncho tarp, which is not a preferential shelter.

[Kevin Babione]

Nick,

I found that the Gatewood Cape works pretty well in the rain. The first time I took it out was on a one-night trip and it rained almost the entire first day and night. If it's really windy you'll want some kind of a belt to keep it from flapping around and up, but it will keep you dry and has pretty good ventilation.

It was nice to see the OP's reference to condensation…I've not had any problems with condensation, but I've never set it up in a locale like that. I do always try to maximize the height of the pitch which does three things:
– More headroom
– More interior space
– Better ventilation

I've staked the Gatewood Cape to the ground when it was a windy storm, but as long as it's windy out condensation hasn't been an issue. I do pitch my pole at an angle (away from the sleeping area) so that if it sags during the night a simple little slide towards me with the pole handle and everything is taut again.

I don't think you'd be disappointed if you bought one. They also appear on Gear Swap fairly regularly.

[Tom Lyons]

I have about the same torso length as you.
I was amazed at how comfortable that Klymit pad was. On my back or both sides.
For me to get up without aches and pains after a night on the ground is unbelievable.
I'm 57 years old, and I get aches pretty easily now. I'm not a kid anymore.
This Klymit pad is doing a great job for being as minimal and light and thin as it is.

The Cape has great room in it. However, if you are 6'2" you are going to be near max length for it. If you pitch it a little further off the ground, it will yield you more room because of the wall angle.
If you like to curl up in a fetal position, there is plenty of room toward the back of the cape, in the middle. You won't touch the back wall at all. Tons of room back there.

I just got the Cape yesterday, and have not used it as a rain poncho yet.
But it has a hood and looks like it will cover everything and keep me and my pack dry, so I'm not too worried. I can tie it up with a belt if it seems to be too long. That's the least of my worries. I don't use trekking poles, so the arm slits won't pose any issues for me. In fact, I will probably prefer the arm slits.

[Tom Lyons]

Last night, I wore a women's shower cap on my bald head to help keep it warm, because the Montbell Thermal Sheet is not a hooded sleeping bag.
It is one of those thin plastic types which "balloon" out much larger than the head, so it can cover the hair-do, and has elastic around the opening.

Well, this thing weighs less than an ounce, has no insulation, yet it kept my bald head completely warm last night. Every bit as warm, if not warmer, than my down insulated Montbell Thermal sheet on my body.

It was behaving as a Vapor Barrier Layer, and also had at least an inch of dead air space all around my head. When I woke up, my head was warm, and there was a little bit of sweat inside the shower cap. Like that "micro climate" was created inside there.

I use this shower cap as part of my VBL kit for cold weather.
Very light, easy to stuff, and waterproof and non-breathable, and it works.
But it does get a little bit "clammy" inside. A quick wipe-off of the top of my head with a towel when I got up, and I was as good as new!

[Author]

Posts