Do nylon canoe pack liners last?

For waterproofing my Duluth-style canoe packs, I’ve been using the cheap thick plastic liners sold for that purpose. I like the fact that they’re cheap enough to be replaced every time so I don’t need to worry about puncture too much.

What is it about nylon pack liners like Granite Gear Air Vent that make them worth the extra expense? Don’t they puncture easily? Is patching easy and cheap?

Also: what’s a good way to test either bag’s water-proofosity?

Answering one of the two questions:

– Last Updated: Jun-24-14 10:01 PM EST –

Testing the "water-proofosity" (I love that word) is as easy as testing the "air-proofosity". Seal the bag, set it on the floor, and push down on it. See if you hear any hissing noises or can detect a gradual decrease in the volume of the bag. Tiny leaks really won't matter much, because your pack will be floating rather than being completely forced below the surface of the water. You could even set that bag in a kid's wading pool or something and push down on it while watching for escaping bubbles (you'd have to turn the bag every which way to get the various parts below the surface), but that's more trouble than I'd go to.

Of course, you need a good way to seal the top if you are that concerned. One way that works well with the heavy-duty plastic liners is to tightly twist the top, then fold that twisted section over on itself before wrapping something around it to keep it cinched. The bent-over twisted section maintains a lot more twisted area. Simply twisting and then tying with a big twist tie or something means that the closed section will only remain tight at the location of the cinching device.

Lots of people just roll down the opening, dry-bag style, which is the least waterproof method of all, but the fact that they are happy with that method shows that you don't need perfection.

we took the scout troop on their first big canoe trip, we had a campout behind my house.

Prior to going into the woods, I threw all of the packs into the pool, fished them out after a few min and we went camping. Mine went in first.

If they wernt packed right they found out.

The look on their faces when I had them line up at the gate to the deck and I heaved mine in and turned around to the next guy was priceless.

with my coated nylon dry bags
Or any dry bag hold them up to a good light source and look into the darken inside of the bag. Any pin hole will shine with light. Use aquaseal or such to seal the hole.

I wish I could do that with my nylon-
urethane flotation bags. But even the few that have dump valves do not allow enough of my eyeball inside.

I just take them into a quiet basement room, where the air is still, and gently put pressure on each bag, using my ear and my cheek to detect leaks. Then I mark them and repair with Seamgrip, itself a urethane. I haven’t had to use a patch, just the goop.

float bags
Would require another way. We use mega bubble when pressure testing drain and water lines with a leak. Repairing inner tubes a soapy water mix, or dunking in a tub of water and watch for bubbles.Of course the way you do it works. Lots of ways to skin this cat.

I wonder how many people use such liners

– Last Updated: Jun-27-14 11:00 PM EST –

The price of those bags is pretty scary, especially when you consider how delicate they look. The fabric really has the appearance that after a bit of flexing at the seal and scuffing from the gear inside, they'd leak like a sieve. I'm wondering if anyone can answer the first part of the question too.

For what it's worth, I recently bought a huge quantity of heavy-duty plastic bags to use as liners. It was the smallest quantity I could get from a non-paddling-supply place, and it's enough to last me an awfully long time.

Testing water-proofosity
Lay out plastic ground cloth to work on in shade of a tree.

“Balloon” (blow it up) the object.

Completely wet outside surface with garden hose.

Generously lather with baby shampoo (if large, do sections at a time).

Press to force air out any holes.

Find holes and mark.


Dry and fix holes.

Object is now water proof

And clean!

I’m cheap
I’ve found that trash compactor bags are pretty leak-proof. Quite a bit thicker than heavy duty garbage bags. I re-use them for at least 5 or 6 trips. Possibly a bit small for a Duluth pack, but they fit mountaineering packs and dry bags great.

I also use the twist and fold over method with a heavy duty rubber band.

I second the trash compact bag
with a goose neck to keep clothes, sleeping bag and camp shoes dry. Patch the pinholes with duct tape. More bomber than many commercial dry bags. Don’t overfill and keep inside a soft pack.

I have two and like them
I got an XL Granite Gear eVent liner for one of my Duluth packs four years ago, and have used it several times on trips. And when storing, I keep gear in my packs plus the liner in my van all the time.

The liners haven’t punctured that I know of. Of course, I don’t put anything sharp inside the liner when I pack. Nor do they come out of the canvas Duluth pack on a trip, so there’s really no opportunity for them to get punctured outside the pack. The Duluth canvas takes the brunt of any rocks and sticks and prickly pears on the ground.

Even if a liner got a pinhole or two, so what? The purpose is to keep out rain and bilge water, not float down the Grand Canyon. Punctures can easily be repaired with seam sealer.

The nylon liners are much more flexible and packable than the thick plastic bags from Duluth I used to use. It’s also easy to squeeze excess air out, if you want to. Just roll the top down, compress the bag, and the air flows out through the eVent panel. If you want to keep the bag slightly inflated, you can do that too.

I liked the liner so much I bought a second one two years ago for my other Duluth pack when I found another sale. I don’t think I’ve actually used it, only because I never take two Duluth packs on a solo trip. Compared to the price of a Duluth pack these days, an on-sale Granite Gear liner is a worthwhile investment in my opinion. No reason it shouldn’t last decades with care.

Ostrum Canoe Pack liner
I have always used the big thick plastic bags and I’ve never really had a major leaking problem. I always pack my down sleeping bag in its own dry bag just to be safe. But - some time ago I was messing around on the internet and I had a few extra bucks in my pocket so I bought an Ostrum Pack Liner to give it a try. Seems pretty rugged and well made. I have only used it once and it worked really well. It is nice to be able to roll the top closure and know its going to be pretty darn water tight. I’ve never had a lot of confidence in the closure at the top of the plastic bags, although I’ve never had a problem with leakage either.

I use sea to summit
Event compression bags for my sleeping bag, and change of cloths when canoeing, kayaking, and backpacking. I have had great success with them. One did get a pinhole in it which was fixed on the trip no problem. I like how small they can be compressed.

Actually, the Event bags
(I think that’s what the OP meant by air vent) are waterproof but not airtight, so that test won’t work on them. They’re compression sacks made of hypalon and are designed to exhale air but not inhale water. I don’t know how they “know” but they’re pretty amazing. I can put my down bag, my daughter’s synthetic bag and two camp pillows in an XL and compress it down to the size of a traditional twenty liter dry bag. I’ve not flipped with it in the boat, but it’s been splashed during aggressive water combat, rained hard on and laid in water all day in a canoe with no water intrusion. Too expensive to use as a pack liner IMO though since the cost premium is due to the compressablility (is that a word?).

I have Ostroms too
after ten years one leaks a little. It might have come in contact with DEET.

No matter… they are no longer available.

No longer available?
Is that something new? I just bought mine last year. Looks like he still has them on his web site.

Bill shut down last winter

Seems like I read about someone
acquiring the business. I’m not positive about that, but if I did it was on That would also be a great place to ask about packs and pack liners. Lots of that kind of knowledge over there.

Probably the fastest way
would be to actually call the number on the website and find out if it works.

Source of your plastic liners?
GBG, where did you get the cheap plastic liners you mention? I had been looking around town a little but eventually gave up and ordered from a canoe website.