I made some major changes this year to my shelter system, switching to a Mountain Laurel Designs Duomid as my primary go-to backpacking shelter, complemented by MLD’s Superlight Bivy.
While the Duomid has been quite spectacular so far, my favorite piece of new gear in 2010 has been the Superlight Bivy. The Superlight has proven itself as a moisture barrier for my sleeping bag under all sorts of tarps, and even beyond tarp camping.
I originally bought the Superlight for use primarily with flat tarps to help control rain splatter, which is rain that rebounds onto your sleeping bag after it hits the ground. When I ordered the Superlight, I had also decided to use it as a way to protect my sleeping bag from the boggy conditions I expected to find hiking across Scotland during the 2010 TGO Challenge.
But the utility of the Superlight and the customizations that I had made to it by Ron Bell at Mountain Laurel Designs extended its utility beyond just tarp camping: I also use it frequently in shelters as a bug net and to keep mice from running over my face at night, a common hazard of shelter habitation on the Appalachian Trail.
A stock Superlight bivy from MLD has a Momentum DWR top, silnylon bottom, an eVent foot panel, and a right or left side, hip-length zipper. There are also other options available for reducing weight or adding additional functions.
When I ordered my Superlight, I had Ron Bell (the owner) configure it with the larger no-seeum netting option and I got an extra-long so I could stow additional gear in the bivy in wet conditions. The total weight of my customized Superlight is 6.8 oz.
Bivy Sack Experience
I’ve used the Superlight bivy on every backpacking trip I’ve taken this year, which totals to about 30 nights of use. I’ve spent most of those nights under a tarp, but a few have also been inside Appalachian Trail style shelters.
During that time, I’ve only experienced condensation on my sleeping bag once, in Scotland, on top of my bag by the feet, when I was camping next to a stream and a mist clung to the ground the following morning. (I was in the Duomid). I hung my sleeping bag on a tree limb and it was dry before the end of breakfast.
Throughout the year, I’ve slept in the Superlight with a Therm-a-rest NeoAir Pad, split evenly between a torso length pad and a regular length pad. During the day, I store the sleeping pad in the bivy sack and roll the two up together. This expedites set up in the evening and is a very convenient way to carry the two items, while further protecting the NeoAir from puncture.
To my surprise, sleeping on an inflatable pad in a bivy sack has improved the quality of my sleep. I roll around a lot of night and frequently wake up in the middle of the night to find myself off my sleeping pad and cold. Sleeping in a bivy sack (where the pad is in the sack with my sleeping bag), keeps me attached to the pad all night. Nice!
When I ordered the extra large netting option on the Superlight, I got it because I thought it would reduce the risk of internal condensation from my breath. This proved to be correct, but the extra netting has also been great as bug protection throughout the year. There’s a piece shock cord attached to the netting that let’s me attach it to a hook inside my tap or to a cross beam in a shelter, and keeps it off my face, and tented above my head.
Like all ultralight gear, the Superlight requires a little extra vigilance in use because it is not as robust as heavier weight bivy sacks. The only time this has really been an issue for me is when the bivy zipper jams on the top fabric of my sleeping bag, a Western Mountaineering Ultralight 20 MF. This happens a bit more frequently than desirable, but gently pulling the two apart easily clears the jam. These jams can be avoided by being more mindful when opening or closing the bivy sack zipper.
While many bivy sacks don’t have zippers and are immune from zipper jams, I can assure you that having a zipper is a great convenience, particularly as night, when you need to get up and relieve yourself. In fact, it’s such a desirable feature, that I’m on the verge of getting a new winter bivy sack that has one too, because I’ve concluded that it’s an essential feature for long winter nights.
Looking back on 2010, I’d have to say that the Superlight bivy has been the one piece of backpacking gear that has had the biggest impact on my camping experience and comfort. If your main shelter is a tent or you sleep in shelters all of the time, then you probably don’t need a bivy sack. But if you’ve shifted to a floorless tarp and want an ultralight bivy sack to protect your sleeping bag from moisture and provide bug netting instead of a much heavier inner tent system, I strongly recommend you consider the Superlight Bivy from Mountain Laurel Designs. It’s a very flexible piece of ultralight gear than can be used in a variety of situations to increase your sleeping comfort.
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