Pack liners vs pack covers

Either way it's a good idea to use a liner, since a cover can still let water in from the backpanel, and a cover won't protect the contents if you happen to fall in a river.

Some people like a cover as well to keep the outside of their pack dryer, but I find them to be too much hassle for too little benefit.

If I used a fully enclosed tent and wanted to bring my pack inside with me, keeping the outside dry might be more important to me, but I use tarps almost exclusively.

Probably a matter of personal choice?
Myself, I use a liner (trashbag) Just make sure the opening is twisted and pointing downward. I zip loc my extra socks, underpants, extra shorts and anything else that needs to stay dry. I personally prefer it to slipping a cover on and off.

I did a little test on the patio a couple of weeks ago. I wanted to see how much added weight a fully-soaked pack would have. I used a 42 L. pack, with one of Lawson's cuben pack liners stuffed with fleece jackets. Rain drizzled nearly all night, fully drenching the pack. The next morning, I emptied the pack and hung it up for 30 minutes to let the excess water drip off. It turned out that the roll top liner had fully protected the contents, and that the drenched pack was 11.0 oz. heavier than when it was completely dry. So…this might support the case for using both a liner AND a pack cover when you know that you will be hiking in full-on rainy conditions. A 3 oz. pack cover could lighten your pack weight by a net of 8 oz.

Wow, that's pretty interesting, Gary. Thanks!

I use a 1.9 oz 18×36 ZPacks cuben fiber dry bag pack liner and a 1.2 oz ZPacks cuben fiber pack cover. I am one of those that would rather carry a little extra weight (3.1 oz) to try and ensure dry gear.

Like has been mentioned already, a pack liner will do well to keep the contents inside the pack dry, but not the pack itself or any items that may be stored in outside pockets.

As well, a pack cover will not completely keep water out. Water will run down between your back and soak the back of your pack and can enter in the pack this way. But a pack cover will keep a majority of the water from getting inside the pack as well as keeping the stuff in outside pockets dry.

I would say it is a personal preference.

"The drenched pack was 11.0 oz. heavier than when it was completely dry. So…this might support the case for using both a liner AND a pack cover when you know that you will be hiking in full-on rainy conditions. A 3 oz. pack cover could lighten your pack weight by a net of 8 oz."

But even with a pack cover the backpanel and straps will get soaked in rain. And that adds some weight, possibly a lot of weight if there is a lot of water absorbing stuff like 3D mesh padding.

That said I stopped using packcover when I started to lighten my load. And I feel that wiht the decision I haven't lost anything else than excessive weight. Instead of one big pack liner I've been using two or three smaller dry sacks to organize gear but now I'm planning switching into one bit liner sack to save some more weight.

That sounds like an enormous amount of water– about 10.5oz. I would expect most of that to be captured in open cell foam padding and most of it could be wrung out. A pack cover won't keep a foam back panel, waist belt, or shoulder straps dry.

The goal is to make sure your insulation stays dry– clothing and sleeping gear. There is no room for compromise in the integrity of your dry insulation; it is purely a matter of survival. A twisted trash compactor bag is an inexpensive light and effective means of keeping your stuff dry.

A poncho will provide rain gear, shelter and keep your pack dry inside and out.

One of the reasons I enjoy this site is someone ALWAYS thinks of something I never thought of.
Not only that but they test their theories out.
Like Mr Garry testing out the wet bag..that was great!
It still hasn't convinced me to use a cover. However,it has convinced me to switch to a mostly syn mesh bag. I have been considering but now I am sure.

I have only ever used a pack liner, so I found the data fascinating –

"The drenched pack was 11.0 oz. heavier than when it was completely dry."

Has anyone worked out how much heavier their pack would be if it was treated with a light water repellant spray? That could reduce water absorption for straps and the entire pack exterior. (Hmmm, I might test it out on my day pack. Then if adds too much weight I only need to suffer for a short while.) It still won't help with river crossings but might be good for those who don't like wearing ponchos.

Be aware that a pack cover also reduces ventilation. If it stays on the pack too long you end up with that mildew smell.

On the subject of the added weight when a pack is wet, It depends a lot on the material used. I suspect dynema and other grid nylons could absorb a certain amount of water, but silnylon, cuben, and other waterproof fabrics should absorb very little water.

I use a pack made of uncoated 1.9 ounce ripstop. When it rains the water runs off the pack or through it and then drains out. The pack dries quickly.

I put all my "must stay dry" stuff in a plastic trash compactor bag within the pack.

The tradeoff is: 11 ozs of extra water weight when the pack is wet VS weight of pack cover all the time, even when you are not using it. Weight/benefit likely depends on the length of the trip and how much water weight your personal pack retains. (Modified Kelty White Cloud user here = not much retained water weight).

Knowing your gear is dry vs. hoping your gear is dry. Go pack liner.

pack liner for sure.

I have used one (contractors bag, plastic) for years (25+). Works great, no worries!

WOW, Digging up the oldies 2011 :)

I will add my experience for reference. About 13-14 years ago I had a cordura nylon Kelty 35 liter pack w rain cover. We were day hiking in June in Great Smoky Mtn Nat Park. A light rain soon turned into a thunderstorm w torrential downpour. It rained for 2.5 hrs. We were hiking fast since we were all soaked. Once to the car I pulled off the rain cover to check my gear. The rain cover was worthless. My gear was soaked except my FAK as it was in a zip lock bag. I had no means of weighing the wet pack, but it felt at least a pound heavier as it was noticeable. It took a few days to dry in our A/C house. I couldn’t leave the pack in the sun to dry as it rains almost every afternoon in June!

Wouldn’t newer pack materials prevent the 11-ounce hit (mentioned earlier in this thread) of carrying a saturated backpack? If so, the argument for using a cover and liner together is moot.

I tried a pack liner once… seemed to make packing the pack harder.. didn’t like that.

I use a pack cover and dry sacks inside for my down clothing and sleeping bag.

I would caution against using either your pack liner or pack cover for multi use that would involve touching the ground… could puncture and cause leaks…

Pack liner for me

thom

I use a Schnozzle  as a dry sack–and to pump up my air pad! very light. but I also keep my sleeping bag and down jacket in dry sacks. I’ve wondered about water weight being added to the pack. But  as others point out, some of that will happen anyway, pack cover or no. And I imagine the shoulder straps and waist belt account for  a good amount of that 11 ounce penalty  for  carrying a wet pack. A pack cover  doesn’t  help in that regard.

Back in my younger years prior to doing no pack protection I wore a large poncho when it rained, and it covered the frame pack nicely and provided ventilation. The poncho procedure for both rain and pack waterproofing has evolved to waterproofing the needed dry equipment with plastic bags to lining the pack with a plastic bag and currently a Dyneema dry bag.

Both, sorta. Schnozzle for down items and poncho over the pack.