Sea to Summit Ultralight: Winter Quilt with a Custom Trapezoidal Baffled Footbox.

Winter Quilt with a Custom Trapezoidal Baffled Footbox.

Last year I got tired of sitting out the entire winter then having to struggle to get my 'trail legs' the next summer. I decided to get out and enjoy the backcountry in the winter. . . but the last time I camped in the snow I was a Boyscout and my memories include freezing all night in a canvas A-frame tent.

After hearing about the easy way to the snow via the tram to Mt. San Jacinto I was determined to get out in the winter. I figured that if I could do a few nights in the local mountains I would be ready for a real snowshoe trip in the High Sierra. I would need a much warmer quilt if I wanted to actually stay warm and enjoy the cold winter temperatures.

It was time to make a Winter Quilt with a Custom Trapezoidal Baffled Footbox.

For the shell I used Pertex Quantum from Zpacks. The weight of this material last year was about 1.1 oz/sqyd. Joe has since started using a slightly lighter version (for more info see Zpacks Material Page).

I used SevenD for my Wearable Quilt a few years ago and really liked the feel of this material. I had a few yards of SevenD leftover so I used it for the liner.

After using the quilt in October last year I found that the sewn-through footbox was not keeping my feet warm enough. I decided to rip out the old footbox and make a warmer fully baffled footbox. To save some weight I designed a Trapezoidal Footbox much like a Katabatic Gear 15 Degree Sawatch quilt. The Trapezoidal Footbox fits the angle of my feet. This design not only saves some weight but it keeps the insulation close to my feet thereby avoiding unwanted air pockets.

Another problem with the old footbox is that during the night most of the down tended to migrate from the top to the bottom, leaving my feet cold enough to interrupt a good nights sleep. This time I made the last baffle much smaller at the bottom to avoid this problem. Now all of the down is forced to stay on top and this seems to have solved the problem.

900 f/p down from Thru-Hiker has been the only insulation I have ever used. The quality has been consistently very good. I ended up using about 15 ounces of 900 f/p down.

Recently I realized that 900 f/p down more efficiently provides warmth than a bivy, so I have been leaving it at home. For example: the lightest commercially available bivy is about 5.5 ounces (see Mountain Laurel Designs Superlight Bivy). Instead of bringing a 5.5 ounce bivy I can stay much warmer by just using 5.5 ounces more down in the quilt. Plus the material that is used in a bivy is the same as the shell material in the quilt.

I used M50 instead of Pertex Quantum for the Trapezoidal Footbox. M50 from Thru-Hiker is a less breathable material than the Pertex Quantum but in my experience this material has a better DWR (water repellant). The stronger DWR used in M50 is more desirable at the foot end as it will better protect my feet from any rainspray when I use a tarp shelter.

The baffles are spaced every 5 inches and I used 0.34 oz/sqyd cuben fiber material from Zpacks. All of the baffles are 2.2" high and I over filled the entire quilt by 30%. If you are interested here is the Down Loft Chart I used to determine the correct amount of loft needed for a 20 degree quilt: Down Loft Chart.

I made this quilt 80" long and 56" wide. I am 6'0" tall and this allows me to wear some layers while sleeping. I was hoping to stay around 22 ounces for the finished product. The material weight was about 6 ounces and I used slightly over 15 ounces of down. On my scale the total weight turned out to be 605 grams or 21.34 ounces. The double sided loft is about 6"!

I used this quilt on a few snow trips last winter. The thermometer on my watch stops working after 15 degrees, but on the three nights when my watch froze up at 15 degrees I stayed warm all night. In the winter I sleep in silk long johns, lightweight socks, down booties, down vest, down beanie and a merino balaclava. I also use a Therm-a-rest Xtherm when sleeping directly on snow or ice.

One night in the High Sierra last winter I ran out of light at the end of the day and I was just too exhausted to setup a shelter. I slept directly on the snow and out under the stars. The sound of the creek flowing under the snow nearby and the wind howling through the trees made for one of the best nights I've ever experienced in the backcountry.

If you have any questions please feel free to send my an email.