If you like the weight savings of quilts, but prefer the draft free cold weather performance of sleeping bags the false bottom design might be for you. A full sleeping bag wraps a full cocoon of insulation around the user that fully closes to keep heat in and airflow out. However, any insulation placed underneath a sleeper is rendered mostly ineffectual when it is compressed by our body weight and we already have the appropriate insulation there in the form of a sleeping pad. So why carry it around? This is why quilts are so popular these days. We just get rid of it. However, quilts can have some drawbacks. Being open on the bottom gets rid of the weight of the bottom insulation that is mostly unused, but means that when a sleeper moves little bits of cold air can sometimes sneak in as the sides lift up or move around. This doesn't always matter if the temperature isn't arctic cold and there are ways to mitigate it. Straps can secure the sides down fairly well and building it a little wider can help make sure the edges remain draped over the sides. The false bottom picks up the best of both worlds. It is essentially a very narrow quilt connected on the bottom with a 12" width of ultralight fabric, turning it into a full sleeping bag. The single layer of ultralight fabric weighs almost nothing, meaning the finish weight is equivalent to an impractically narrow quilt, with draft free performance of a sleeping bag with a generous inner girth. I use a single strap to attach the bag to your sleeping pad and keep you on it with the false bottom down. The use of this strap is optional. It is fully removable. The sides of the false bottom can also be pulled together by removing the strap and clipping the sides together, turning it into a narrow sleeping bag with full wrap down insulation.
