To protect your pack contents from rain there are the
options of using some type of dry sack inside your pack
or a raincover over your pack.

I'm of the thinking that a pack raincover would keep the rain off your
pack so you won't be carrying a damp
and therefore heavier pack whereas internal
protection leaves your pack exposed
to the elements.

Is there more to it?

(river crossing, well, that's a different story).

the general consensus on pack covers is the it doesn't stop water from getting b/t the pack and your back. the pressure forces the water through sometypes of raingear. hence, the predeliction for capes and ponchos as raingear to prevent this from happening. also, packstraps and hipbelt still get mighty wet. i've only experimented with them a couple of times when a friend gave me one (thanks again, GR). i prefer the poncho or cape, but then i don't do much real bushwacking where a cape or poncho will snag and get torn on brush and thorns. much has been written on this before. a search of the Forums might yield much better info than i've included here.

for those that don't, or can't, use a cape or poncho, the packliner is the method preferred by the Gurus of UL trekking (i.e. packliner vs. a packcover).

Edited by pj on 01/05/2007 04:36:08 MST.

For the longest of time now, I primarily used just a trash bag or trash compactor bag inside my pack. The amount of water the nylon of most packs absorb is really quite negligible. In the smaller packs most people carry in the lightweight world, this likely is no more than the weight of a pack cover. Once the pack dries, no more extra weight. But if you carry a pack cover, you're always carrying the extra 3-4 ounces.

The areas which DO absorb a fair bit of water, the suspension aren't helped by a pack cover. And the interior is protected in case I should ever have a leak in my hydration bladder. I suffered my first pinhole leak in 6 years of carrying a platypus this past summer and was glad for the interior liner. Conversely, I kept my gear dry despite nearly two weeks of continuous misty rainy weather on the Colorado Trail in late June and early July.

If I KNOW I'm going into a truly rainy place, like the Smokies in February through April, I'll sometimes take both the bag liner AND an pack cover.

I agree about using both liner and pack cover when the weather is abismal. And I agree with all the arguments in favor of liners, and I use them... just not alone.

I like a pack with lots of pockets and I use a poncho most of the time. The poncho does not make additional protection unnecessary, just redundant. Redundant is good. If I take the pack off, the cover protects it. The pack cover is also a water bag and gear hammock. When I get to camp, it contains the pack explosion as I unload everything. The liner (if I am using one) is still inside the pack and is of little organizational help.

In addition, while it is true that the nylon of a pack will absorb little water, the pack can collect and hold quite a lot. If the liner is compromised, water pressure inside the pack can force water through.

On the AT in '03, I used a liner, a pack cover AND a poncho. Anyone who was on the trail that year will understand that only redundant systems and careful procedure could keep anything dry in the record rainfall.

Edited by vickrhines on 01/05/2007 08:54:14 MST.

I've always favored liners for the reasons given above. In the latest issue (#6) of BPL Magazine, I was surprised to see Ryan recommend a pack cover rather than a liner in the "Cold & Wet in the Pre-Winter Months" article. The reason given "to shed snow and prevent my backpack - and its contents - from absorbing excess moisture weight." Was snow the deciding factor for Ryan? My guess is that in the late fall your pack is unlikely to dry so protecting it becomes an issue. Shedding snow may be secondary. The gear list that accompanied the article did not list a liner or a cover.

I prefer using an internal liner. It's simple, effective and it keeps everything dry inside. An external cover isn't 100% effective.

ian,

I don't use either a pack cover or an internal liner and still stay dry in pretty awful weather.

Outside is a poncho because it protects your harness and keeps water from running down between your back and pack. Also jackets tend to leak below the shoulder straps.

Some items do not need to be protected from the rain like my kitchen and water system.

Some items like a hammock in water proof snake skins are adequately protected by the combination of the poncho and water proof container.

Most packs are made from a coated fabric that is highly water resistant.

Inside the pack are separate plastic or silnyon bags. And sometimes the contents of those bags are in bags. As an example Ramen noodles are protected by:
1. Poncho,
2. Pack cloth,
3. Food bag, and
4 Plastic bag.

Interior liners are very effective however. You can double line the pack with plastic bags and the contents will stay dry even if you swim the pack - short swims only.

Edited by food on 01/05/2007 13:09:05 MST.

I needed to go to lunch and did not finish my previous post.

The lightest, cheapest and most durable way to stay dry is technique and not gear.

In the morning the pack should be packed inside the shelter then stow the shelter outside the main compartment. You should carry enough stuff in your pockets that the pack main compartment is not opened all day. You need to be able to set up and open the main compartment inside after the shelter is set up. The packing order and location needs to be changed so that this can be accomplished.

Edited by food on 01/05/2007 13:09:47 MST.

There is useful discussion about pack covers v. liners on this thread. I took Ron Moak's advice and used a pack liner in addition to my poncho on the Wonderland Trail this fall. Good advice. The pack ended up wet in spite of the cover, but my gear inside the liner remained dry. I also used a UL dry bag for misc. gear and seam-sealed my down quilt sack, but that third level of protection wasn't needed.

Edited by Otter on 01/05/2007 13:17:13 MST.

Excellent advice !

Should I start another thread asking
if ponchos get all hot and sweaty ?

I use a liner bag since it is protected from brush and rocks that could cause damage without me noticing it...until it's too late. Plus it's alwys on so I don't have to stop and put it on if it starts to rain. Also, I've seen a pack cover go airborne and disappear during a VERY windy day on Roan Mountain along the AT.

Question:
Has anyone seen an advantage between a trash bag (I usually use a compactor bag) and one of the commercial (e.g., Sea to Summit's Ultra-Sil) pack liners?

Tom

I use a pack liner for my sleeping bag only. Everything else in my pack I have pretty much coaxed into a weather hardened and waterproof state and it doesn't matter if it gets wet. I don't carry a lot of extra clothes. The only exception is my Mont Bell down inner jacket. I roll this up and put it at the top of my pack, which rolls up like a dry-bag. I have never had it get wet up there even in really awful rain. I do carry a silnylon pack cover that I really trust so I am sure that's a huge factor here. I get those liner bags from ProLite Gear in a 3-pack but one will last pretty much an entire season... but I baby my gear.

I generally use a pack cover in conjunction with waterproof bags for moisture sensitive items in my pack. I have my bag and down jacket in waterproof roll-top sacks (sleeping bag sack doubles as bear bag, jacket sack as pillow) and any other small items in ziploks or aloksaks.

I think pack covers show more advantages in shoulder seasons or winter, where frozen and snow covered pack fabric can be a real pain, and ponchos or capes aren't really practical. Also, when opening your pack in an unsheltered area, you can use the cover as a mini tarp of sorts while you dig through your pack.