There are occasions when a dry sack might appeal to a lightweight backpacker, for example when canyoneering, or in extreme wet weather as found in Patagonia, New Zealand and the US Pacific Northwest to name a few locales. But under what conditions can you expect a lightweight dry sack to keep your gear dry? How about if you fall when crossing a river, don't have room in your bivy and leave clothing in a dry sack out in the rain all night, or, as happened to one of our staff in Patagonia, unpack in camp in the evening to find that your pack is holding a couple of inches of water in the bottom - where your sleeping bag is?
Descriptions on manufacturer web sites aren't of much help, only emphasizing that the dry sacks are waterproof. A typical description (from Outdoor Research) is, "This dry sack offers lightweight, compressible protection. The fabric has a waterproof coating and the seams are taped to keep moisture out. A roll-top closure keeps your gear dry and secure." There is no mention of the limit of conditions the bag is expected to keep gear "dry and secure." Performance is caveated by all the manufacturers of lightweight dry sacks I tested (except Outdoor Research) somewhere, at a minimum saying that the bags won't withstand extended submersion, and often that valuable items should be double bagged. Only Granite Gear mentions any caveat on their website, other companies mention the limitations on the packaging or in the instructions inside the package.
I put the lightest dry sacks available from Outdoor Research, Sea to Summit, Granite Gear, Cascade Designs (SealLine), and Pacific Outdoor Equipment through five tests. My objective was to understand the performance limitations of these dry sacks. The test methods and results follow.
ARTICLE OUTLINE
- Introduction
- Dry Sacks Tested
- Granite Gear Drysack
- Cascade Designs SealLine Storm Sack
- Outdoor Research HydroLite
- Sea to Summit Ultra-Sil
- Pacific Outdoor Equipment WXtex Pneumo Lightweight
- Tests
- TABLE: Test Results
- Observations from the Tests
- Roll Tops
- TABLE: Water Weight Gain
- TABLE: Manufacturer Claimed Weight vs. Measured Weight
- TABLE: Weight Comparison for Similar Sized Dry Sacks
- Overall Observations
- TABLE: Plus/Minus
- Recommendations for Consumers
- Recommendations for Manufacturers
# WORDS: 4100
# PHOTOS: 10
# TABLES: 5
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Discussion
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Companion forum thread to:
Lightweight Dry Sacks: Comparison Testing Results
Jason, You are correct. I guess I had the other “E” word on my brain.
I did a little editing of the other post.
I want to let BPL'ers know about the dry sacks from Mountain Equipment Co-op (MEC.ca). I think these are new. MEC is sort of the Canadian equivilent of REI.
http://www.mec.ca/Products/product_detail.jsp?FOLDER%3C%3Efolder_id=2534374302701623&PRODUCT%3C%3Eprd_id=845524442628934
I have the 7L size which I easily fits my Ultra 20 quilt and then at night I fill it with stuff for use as a pillow. This dry sack weighs 41g (1.4 oz) after I trimmed the pocket off the bottom. These dry sacks have a velco pocket that sorta hangs off the bottom that allows you to stuff the stuff sack into. The pocket adds about 10g (0.3 oz).
Without the pocket, these sacks are just as light as the lightest sack in this comparison test although I guess mine is a bit smaller than the sizes used in the test.
The cool thing about these dry sacks is the price. Mine was just $8 Cdn which is about $7 in USA funds. They are available in 5 sizes which go up to 28L for $15.
I filled mine up with water and held it for a while and no water was leaking out the seams. The roll top isn't as ridgid as some drysacks, so you want at least two rolls in…probably 3….to get a good seal. I'm not sure how the roll top would fair in BPLs test, but the body of the sack seems to be watertight. For my uses (keeping my down bag dry inside my pack) this sack is definitely waterproof enough.
Hopefully this doesn't sound like an ad. Previously I was using the 10L SealLine storm sack (the same one used in this test) which worked well but it was a lot heavier (40g vs. 77g) and I didn't really need 10L. Now my dry sack is half the weight….plus the color matches my Ultra 20.
MEC also makes similar dry sacks in larger sizes that are intended for use as a pack liner. These are $11 – $18.
http://www.mec.ca/Products/product_detail.jsp?FOLDER%3C%3Efolder_id=2534374302699989&PRODUCT%3C%3Eprd_id=845524442625580
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