Send us a suggestion!

Tech Tip: Answered Canyoneering Pack Water Absorption Test

Discussion in 'Tech Tips and Gear' started by ratagonia, Oct 13, 2017.

  1. ratagonia

    ratagonia

    Messages:
    3,668
    Likes:
    4,184
    Location:
    Mount Carmel, Utah
    Canyoneering Pack Water Absorption Test
    October 12, 2017
    Technicians: Tom Jones, T.J. Cottam


    Preface
    I have made, in the past, the claim that in comparison to Euro-style PVC-laminate packs, Imlay packs are lighter, and lighter even when wet. Other people have claimed that Imlay packs get heavy and unpleasant in full wet conditions, and that the Euro-style packs have a distinct advantage in this aspect.

    My claim was based on a comparison of the fabrics. Imlay packs are built mainly of 12 oz Cordura, which when saturated may weigh as much as 14 oz per square yard (new fabric); whereas the Euro-style packs are generally made of a 16 or 18 oz laminate fabric. This is a dubious way of justifying the claim. Obviously, whole pack testing would be much more relevant .

    Procedure
    For this test, I used a well-worn Imlay Kolob pack with the frame removed, and a brand new Kolob pack with the frame removed. With the rigid frame, the pack would not fit in the available tub, and the frame is unlikely to absorb significant water, being made of aluminum tubing and plastic sheet, plus a little bit of webbing. The well-used pack is not the current model, and the current model is lighter; however, the materials are very similar in amount and character so it is likely the water absorbed is a good representation of the water retained by the Kolob pack in its various iterations through the years.

    First, the used pack was weighed dry without the frame on my shipping scale. The scale is accurate to about 10 grams. Weighing the packs required setting a box atop the scale so no parts would hang off the scale. In weighing a WET pack, this is an advantage because the cardboard box would catch and retain any moisture off the wet pack, thus the weight is captured at the moment the pack is placed upon the box. As part of the process, the weight of the box was recorded each time just before the pack was placed atop it.

    After being weighed dry, the pack was immersed in a big yellow tub of cold water and held under the surface by another big yellow tub with a cracked bottom, in which weights were set. Immersion time was 1 hour (+10/-0 minutes). At the appointed time, the weights were removed and the pack withdrawn from the water, briefly turned upside down to spill captured water, then held upright by the handle. The wet pack was then weighed at 45 seconds, 3 minutes and 5 minutes from tub removal. While being weighed, the pack was horizontal; between weighings, the pack was kept upright and vertical, leaning against a post on a concrete floor.

    This test was repeated with a brand new Kolob Pack.

    T.J. Cottam then did the same test on a well-used Rodcle 45L Consusa, which is about 10% bigger than a Kolob pack.

    Results
    Weights stated have the weight of the box subtracted, and do not include a frame. All weights in grams.

    Used Kolob pack
    Condition...........................Weight.......................................Water Weight Retained

    Dry.......................................1610.................................................0
    Wet after 45 seconds.............2895.................................................1285
    Wet after 3 minutes...............2595.................................................985
    Wet after 5 minutes ..............2480.................................................870

    New Kolob pack
    Conditiom.........................Weight.........................................Water Weight Retained

    Dry......................................1490.................................................0
    Wet after 45 seconds............2230.................................................740
    Wet after 3 minutes..............2125.................................................635
    Wet after 5 minutes..............2070.................................................580

    But, let’s ‘normalize’ these numbers to include the frame, thus adding 130 grams to each of the pack weights.

    Used Kolob pack WITH frame
    Condition..........................Weight.......................................Water Weight Retained

    Dry......................................1740................................................0
    Wet after 45 seconds............3025................................................1285
    Wet after 3 minutes..............2725................................................985
    Wet after 5 minutes..............2610................................................870

    New Kolob pack WITH frame
    Condition..........................Weight.......................................Water Weight Retained

    Dry......................................1620................................................0
    Wet after 45 seconds............2360................................................740
    Wet after 3 minutes..............2255................................................635
    Wet after 5 minutes..............2200................................................580

    TJ provides the following report:
    Well used 45L Consusa
    Dry......................................3 lbs 11 oz - 1672 grams
    Wet after 45 seconds............4 lbs 10 oz - 2097 grams...................425 grams of water
    Wet after 3 minutes..............4 lbs 7 oz - 2012 grams.....................340 grams of water
    Wet after 5 minutes..............4 lbs 6 oz - 1984 grams.....................312 grams of water

    TJ continues: Water absorption should be very close on all the packs from 35L to 45L, the back panel and straps that are going to absorb water are identical on all three packs, they just get wider from your back out to the outside of the pack to accomplish the additional volume. So the additional size is all made up of non-absorbent materials.

    Extrapolating the Consusa results to the Lekime 40L (not tested):
    Dry......................................3 lbs 5 oz - 1502 grams
    Wet after 45 second.............4 lbs 4 oz - 1927 grams.....................425 grams of water
    Wet after 3 minutes..............4 lbs 1 oz - 1842 grams....................340 grams of water
    Wet after 5 minutes..............4 lbs 0 oz - 1814 grams....................312 grams of water

    Technical Notes
    Dry weight of the 2016/17 Kolob Pack, with frame, is 1620 grams. The newer editions of the Imlay packs tend to be lighter, AND the old pack might have a bit of sand trapped inside it. As expected, the NEW pack retained considerably less water.

    While the Cordura fabric (Imlay packs) starts out somewhat hydrophobic, after use it becomes scratched up and much less hydrophobic. We expect (and see) a substantial difference between the well-used and the brand new pack. On the other hand, most of the fabric of the Rodcle pack is a PVC laminate which is durably hydrophobic. While not tested, we expect that the used vs. new difference for the Rodcle pack is considerably smaller than for the Imlay packs.

    Comparison
    Here are the numbers re-arranged for the Kolob used with frame, Kolob new with frame, and (projected) Lekime 40L:

    WEIGHT
    Condition...............................Kolob New...............Kolob Used.........................Lekime Used

    Dry............................................1620..........................1740......................................1502
    After 45 secs..............................2360..........................3025......................................1927
    After 3 mins...............................2255..........................2725......................................1842
    After 5 mins...............................2200..........................2610......................................1814

    WATER WEIGHT RETAINED
    Condition...............................Kolob New...............Kolob Used.........................Lekime Used

    Dry.............................................0...............................0...........................................0
    After 45 secs...............................740............................1285.....................................425
    After 3 mins................................635.............................985......................................340
    After 5 mins................................580.............................870......................................312

    (One pound is 453.6 grams.)

    Conclusions
    Packs retain water, even when empty.

    Comparing the water retained after 5 minutes, we see that the Rodcle Lekime retained 312 grams or 11 ounces, the new Kolob retained 580 grams or 20.5 ounces, and the used Kolob retained 870 grams or 30.7 ounces.

    My first conjecture, that the Kolob pack is lighter than the equivalent Euro-style pack, does not hold up, at least in comparison to the Rodcle Lekime.

    It is seen that the Rodcle pack retained the least water, about 60% of what a new Kolob retains; and that the well-used Kolob pack retained 50% more water than the brand new Kolob pack.


    Thanks to Hank Moon for editing but mostly for prodding for a more thorough test.
  2. Taylor

    Taylor

    Messages:
    143
    Likes:
    93
    Good story but what I got from this is that my well used Kolob pack has an internal frame that I never realized was there. It appears I have been hard on that frame as the two aluminum bars are badly bent and asymmetrically curved. Did they start out straight? Sorry this is off-topic.
  3. ratagonia

    ratagonia

    Messages:
    3,668
    Likes:
    4,184
    Location:
    Mount Carmel, Utah
    Tubes have been upgraded in the last couple years. I'll bring a set for you next week. ps, Kolob and Heaps are different lengths.

    Tom
    Taylor likes this.
  4. Canyonero

    Canyonero

    Messages:
    578
    Likes:
    614
    Sorry Tom, having used both styles I didn't need formal testing to tell me that!

    Your best defense is that the pack itself absorbs so much less water than the stuff inside like potshots and sandtraps and webbing and etriers that you shouldn't worry about it.

    Now, can you design a pack that I don't have to replace once a year? :) This next year I'm going to try smearing roofing sealant all over the lower outside corners BEFORE I use it and hopefully if I do that 2 or 3 times a year I'll be able to get two years out of it. Don't feel bad, the Euro-style didn't last a week. I'm still trying to decide which puts less wear on the pack, sliding down an elevator with it or just dropping it down the elevator.

    Bootboy says I'm hard on gear. I tell him that I'm an ideal gear tester. :)
    Ram, Yellow Dart and ratagonia like this.
  5. Rapterman

    Rapterman

    Messages:
    848
    Likes:
    1,161
    Kudos to Ratagonia for posting this test
    But what is NOT included here are the numerous advantages of the KOLOB.
    I happen to own both a Kolob and a Euro vinyl pack and I never wear the Euro one.
    The Kolob has superior suspension with removable stiffeners and a bivy pad (I use it for a climbing approach pack also)
    The Kolob also has a nice generous top pocket for organizing stuff, an internal hydration pocket,
    great drainage, a superb SHAPE for down climbing, and the best designed helmet pocket ever put on any pack, ever.
    :twothumbs:
    Ram, Blake Merrell and Yellow Dart like this.
  6. Tom Collins

    Tom Collins

    Messages:
    440
    Likes:
    601
    Location:
    Woodland Hills, UT
    If there's gonna be a lot of downclimbing I like to have the pack on a tether thats long enough to keep it permanently attached, and when I get to an elevator I just take the pack off, dangle it, and slide down the drop. Just make sure you remember that the pack is attached to you, soon after I started doing this I forgot I had it attached and chucked the pack into a pool that I was gonna downclimb in to. Seeing a heavy pack come to the end of tether as you're standing on the edge of a lip is something of an OH $h!^ moment. Fortunately the water was deep.
    Ram likes this.
  7. Canyonero

    Canyonero

    Messages:
    578
    Likes:
    614
    That reminds me of a certain pothole escape where I did a pack toss and forgot to hold on to the tether attached to the pack. And there I was, standing there waiting to boost you out now that my pack had already escaped the pothole.

    At any rate, you may be right. There may be less wear from the pack dangling/sliding below you than from wearing it on your back. But the additional wear on wetsuit/shorts/harness/shirt etc may make up for that. Plus the hassle of taking it on and off more often saps some time and energy. I also just feel like I can climb better most of the time with the pack on than with it swinging around getting caught on stuff.
    Ram and Tom Collins like this.
  8. Canyonero

    Canyonero

    Messages:
    578
    Likes:
    614
    For sure. The main downside of a Euro pack is it isn't very comfortable. If your load is light and the approach is short, that's no big deal, but otherwise....
Similar Threads: Canyoneering Pack
Forum Title Date
Tech Tips and Gear On Rope Canyoneering (rappel device, packs, rope bags, etc.) Aug 22, 2016
General Discussion ICE CUBE CANYONEERING PACK Nov 3, 2015
General Discussion NEW CANYONEERING PACK Aug 29, 2014
Archives - Yahoo Canyons Group best 7 day backpacking option from Canyoneering 2 Jun 5, 2012
Archives - Yahoo Canyons Group Combining Backpacking, Canyoneering, and Mt Biking Jul 27, 2011
Archives - Yahoo Canyons Group Zion: Packraft/Canyoneering Access May 5, 2011