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Reader Reviews

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Sea to Summit Ultra-Sil Dry Sack

in Miscellaneous Products

Average Rating
4.33 / 5 (6 reviews)

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Al Shaver
( Al_T.Tude - M )

High Sierra and CA Central Coast
Sea to Summit Ultra-Sil Dry Sack on 05/13/2006 22:56:04 MDT Report Post Print

Rating: 5 / 5

I have yet to find a stuff sack manufacturer (including MontBell & Sea to Summit) that understands the importance of a stuff sack also being a compression sack. I'm primarily putting clothes and sleeping bags into my stuff sacks. The smaller the gear, the smaller, and therefore lighter, my pack can be.

For the past 15 years Montbell has sold a well made, lightweight, water resistant (and unbeknownst to them-gear compressing) Aquapel sack. Unfortunately, they haven't kept up with the evolution in lightweight fabrics.

Enter Sea to Summit. The $14, 37gm/1.3oz Aquapel #2 bag corresponds to the Sea to Summit 4Liter bag $11.95 (REI), 23gm/.8oz. The 8L bag is only 8gm more @1.1oz and 13L comes in @ an additional 5gm for a 1.3oz total. These are my digital postal scale weights which vary a bit from the manufacturer's claims.

These bags close typical dry bag style: pack gear tightly into bottom of sack, kneel on sack to expel air, roll down open end of bag until it meets gear and clasp side release buckle.

The only improvements I would make would be to use 2 of Montbell's construction ideas: replace the unnecessarily burly hypalon open end stiffener strip with grossgrain ribbon and lose the "Hulk Hogan" fastener in favor a lightweight center release watch band fastener.

Of course there are still lighter fabrics in use by Bozeman Mountain Works, but I'm not sure that the lesser durability and the hassle of customer seam sealing would be worth the small weight savings.

Update: Shelley at the US office informed me that their target demographic is adventure racers who appreciate the greater waterproofness of the hypalon strip and strength of the robust side release buckle which they use to attach the bags to their packs. The lighter materials would suffice for my purposes (and I suspect for adventure racers too), but that's their reasoning.

Edited by Al_T.Tude on 05/27/2006 01:47:30 MDT.

Price comparison from GearBuyer:
Sea To Summit Compression Sack priced at: $18.95 - $32.90
Sea To Summit Dry Sack priced at: $10.95 - $24.99
Sea To Summit Ultra-Sil Dry Sack priced at: $9.95 - $32.95
Sea To Summit Stuff Sacks priced at: $6.95 - $13.95
Shop Dry, Montbell, These products at GearBuyer
( sheilabaynes )
... on 05/21/2008 15:26:18 MDT Report Post Print

Rating: 5 / 5


Edited by sheilabaynes on 10/30/2014 11:41:13 MDT.

Bob Bankhead
( wandering_bob )

Oregon, USA
available in eEVENT as well on 05/21/2008 21:08:17 MDT Report Post Print

Rating: 5 / 5

In addition to silnylon, Sea to Summit also now makes their Dry Sack line in eVENT fabric, both with and without compression capability.

evac Dry Sack: available in 3, 5, 8, 13, 20, 35, and 65 liter capacities ranging from 1.5 to 5.2 ounces.

Compression Dry Sack - compression system is an attached part of the bag, not a separate system. Can't get lost. Available in 6, 10, 14, 20, and 30 liter capacities ranging from 3.7 to 7.4 ounces.

I bought the evac dry sack for clothes and things that don't need compressing, and one eVENT compression dry sack for my Western Mountaineer down bag. Made a big difference in the bulk in my pack.

Gotta love them!

Price comparison from GearBuyer:
Sea To Summit Dry Sack priced at: $10.95 - $24.99
Sea To Summit eVAC Dry Sack priced at: $14.32 - $39.95
Sea To Summit eVent Compression Dry Sack priced at: $23.95 - $44.95
Shop Dry, Western products at GearBuyer
Mary D
( hikinggranny )
They are now waterproof! on 10/18/2008 14:07:20 MDT Report Post Print

Rating: 5 / 5

In the past, I've read in a number of places (including Jim Wood's excellent article on "Keeping Your Critical Gear Dry") that these sacks have failed the submersion test. This problem was also noted in a 2006 review here on BPL.

In early 2008 I bought a 2 L Sea to Summit Ultra-Sil Dry Sack so I could keep my "essentials" (which include a PLB) on my belt in a waterproof bag when wandering around away from camp (on the trail, of course, it's in my pack). Before using the dry sack, I tested it by turning it inside out, filling it with water and hanging it in my shower for 15 minutes to simulate submersion. There was not a single leak and no "sweating" of water through the fabric as has been reported previously and illustrated by photos in Jim Wood's article.

For several years I've used a trash compactor bag as a pack liner. I fought with it quite a bit--when I pushed an item down into the pack it would pop right out again because of the slippery plastic. I therefore decided to get two more of the Ultra-Sil Dry Sacks, one for my sleeping bag and night clothing (base layer) and one for my insulating outer clothing, instead of using the trash compactor bag. I tested both in the same manner before using them, with no leaks.

Unfortunately I didn't save the weight numbers--I wish I had! I did determine that he weight differential between the Ultra-Sil Dry Sacks and comparably-sized silnylon stuff sacks was the same as the weight of the trash compactor bag. Using the dry sacks instead of the trash compactor bag did not, therefore, involve adding weight.

The dry bags earned their keep last summer when I slipped and fell while crossing a difficult ford. I was completely soaked, my boots were full of water and, when I unpacked my pack, there was at least an inch of water in the bottom of it. The whole pack went into the water. I was too far from the trailhead to hike out in a day, so if my insulating outer clothing and sleeping bag had gotten wet, I'd have been in a bad way (the weather was cool and rainy). Not a drop of water got inside!

I will continue to test these dry sacks each year to make sure they are still waterproof.

It appears that Sea-to-Summit has observed the independent test failures of the past and significantly improved this product. I'm very glad to see it!

Edited by hikinggranny on 11/23/2008 17:11:33 MST.

Price comparison from GearBuyer:
Sea To Summit Dry Sack priced at: $10.95 - $24.99
Sea To Summit Ultra-Sil Dry Sack priced at: $9.95 - $32.95
Sea To Summit Stuff Sacks priced at: $6.95 - $13.95
Shop Dry products at GearBuyer
Art Sandt
( artsandt )
for what it is, thumbs up on 11/01/2008 11:42:24 MDT Report Post Print

Rating: 5 / 5

Those reviews that gave the ultra-sil dry sacks points off for a submersion and hose spray tests were unfair and unrealistic. These are meant to be packed inside a backpack, not used as kayaking bags. Inside a backpack, they work really well. However, I have never been able to use them as compression sacks because after you kneel on what's inside to purge the air out, you have to sort of let up a little in order to roll the top closure 3-4 times and some air always ends up getting back in. I could never get the hang of it if it indeed is possible. My experience has been using these in the rain, inside my backpack, and they've kept my gear dry every time.

Edited by artsandt on 11/01/2008 11:44:09 MDT.

Shop These products at GearBuyer
Adrian B
( adrianb )

Auckland, New Zealand
They leak, at least the older models on 07/06/2009 19:16:20 MDT Report Post Print

Rating: 1 / 5

Note: rating based on 3 different sacks purchased sometime over 2007->early 2008. Reports suggest that later versions of these sacks have improved, but I'll never buy another one. I strongly suggest you *thoroughly* test these before relying on them in the field. 15 minute tests or a single dumping into water isn't enough, think about it being crammed under pressure for 10+ hours into a soaking pack which is moving and stretching the whole time.

**NOT** waterproof, even when new, and they got worse with use. The seams leaked and the fabric leaked under sustained wet conditions. I had this experience across two different sizes of the bags, and the pack liner (so all 3 I've used have leaked).

My inadvertent real world tests involved putting a paperback at the bottom of the bag, before stuffing my sleeping bag in. Then just wait for it to rain hard for a day, or alternatively cross some deep water (one 'test' was half an hour swimming/crawling through a swamp). The paperback came out wet each time (fortunately absorbing some water that my sleeping bag would have otherwise sucked up).

Or, for a quicker and less upsetting test in the comfort of your own home, fill them up with water at the basin, and watch the water dribble out the seams and bead on the surface.

I tried sealing the seams with seam sealer to no avail. Eventually the seam taping, which was poorly applied and didn't work well when new, came off completely.

They work fine as a regular stuffsack/backup inside a polythene bag. The clip/roll top is a good design because it lets you reduce the volume of the bag. But none of that is much comfort when you've got a wet down sleeping bag.

Similar experience to mine at

I've switched to using a polythene bag with a cuben stuff sack inside, which is still lightweight and has never leaked. I would say either one alone is more waterproof than the SS silnylon bags.

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