Ultra-Sil Dry Sacks

The store where I often buy things were out of my favorite brand of dry bags.

They did have Sea to Summit Ultra-Sil Dry Sacks.

Going by what it says on the packaging, the fabric is waterproof, the seams are sealed and it has a waterproof closure.

Since I have no experience with them, I’m a bit nervous. I don’t want to find out the hard way that they don’t work.

Anyone used these bags?

tests say: no
These are the partly transparent bags, right? If so:

BackpackingLight.com did a test and found that the seam on the circular-bottom bags leaks a lot (get the straight bottom seam), and that the opening on all the bags leaks. They found that the fabric itself did not leak.

A test at jwbasecamp.com found that the fabric itself leaks.

I read the methodologies but can’t remember them, only that I found the tests persuasive. I won’t be relying on any silnylon bags. I’ve had good experiences with silnylon pack covers and silnylon tarps, so maybe I’m being too harsh.

I have a longer writeup of the tests of various bags, if you’re interested in all things drybag.

– Mark

too delicate
I’ve used them as liners for bike bags, never used them in kayak use but my gut sense is that they are too delicate for jamming stuff in and jamming in a kayak. Essentially they are very high end tough plastic bags.

absolute garbage!
Sea to Summit usually has decent gear but these “dry” bags are just useless.

The sealing tape comes off in no time.


mine work fine
I filled them up with water and they never leaked. Put them in a hatch filled with water and they were fine, a little moisture inside, but no more than any other nylon drybag.

I’ve been using them for about 3 years now and haven’t had a single one show signs of wear. My oldest bag I’m using as my ditty bag for soaps, toothpaste, medicine, etc that I carry around to many places, probably used 250 times a year. That bag is still fine.

I would describe myself as a professional user of gear. I am certainly happy with these bags. I may not treat them like they are vinyl bags, but the weight savings are certainly nice.

ultra sil
I’ve used a few of them on a couple trips and they are still going well. I can squeeze all of the air (I mean - its like vacuum bagging meat at a butchers)out allowing more room to pack. Do take it easy with them though as they seem to be thin, but so far - fine.

maybe I had a bad batch
but on mine the sealing tape just peeled off after a week. I heard from other users that they had the same problem so I did not bother getting any more or even returned them for warranty claim.

Tony, you must have had a different batch or something.

Mine are about 2.5 years old.


I’ll keep it in mind

– Last Updated: Jul-01-08 10:40 AM EST –

when thinking about a longer trip. Gnarlydog, is that Dom from the Queensland club? I bought some seamgrip for the tent, which may come in handy if ultra-sil seams fail. Still going with my cheap 'Jackaroo' dry bags suggested at a club meet last year. Show and Tell can pay off!


Seamgrip won’t stick
to silnylon. I have peeled off whatever was left of the seam sealing tape and used Silnet (same manufacturer of Seamgrip but specially formulated for siliconized nylon) to seal the seams. Not pretty nor easy but the bag is now kind of waterproof. Could not really be trusted in a flooded hatch though.

Gnarlydog QSKC

the coating is on the outside
the inside of Sea to Summit and OR sil-nylon bags actually have a very thin PU coating that both the logo is screen printed to in mirror image, and the seams are taped to. You should have no problems seam sealing the bag from the inside. Seam sealing from the inside of the bag should stick regardless of whether you use sil-net or not.

I have had Sea to Summit

– Last Updated: Jul-02-08 11:07 AM EST –

dry bags for four years now and the sil nylon dry bags for two years now.

Have used the sil nylon so far on 90-100 camping nights. The others for about 200 nights.

They have been immersed in a rapid for a mile with no leakage. Dont ask; dumb accident.

They are not intended for use as a stand alone dry bag. I use them inside my pack and they never come in contact with a sharp edge. I would use vinyl dry bags for anything needing abrasion resistance.

DEET will absolutely destroy the inner laminate. Been there done that

Ultra- Sil Bags
I’m on my second year w/three of them and no issues at all. The only time I use any of them alone, however, is to throw a change of clothes in a canoe, with the bag snapped around a thwart. Otherwise, they are used inside other bags of various sorts. But they sure are light and easy to pack and compress. I’ve become a fan.