Forum Index » Editor's Roundtable » Mountain SuperUltraLight Backpacking – Going SUL in the Mountains with Adequate Shelter, Insulation, and Rain Protection. Part 1: Concepts and Scope.


Display Avatars Sort By:
Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Metabolisms, ponchos and capes on 05/20/2013 09:55:06 MDT Print View

You're welcome!

Agreed on the variations on cold tolerance and metabolism. Aclimitization is a big part of it, as well as gender and just plain genes. I always remember Darwin writing about the native people of Terria del Fuego and the Europeans standing around a huge bonfire. The Europeans were freezing while wearing layers of wool while the locals were nearly naked and sweating from the heat of the fire. Your body adapts to extremes over time.

The real thing to grasp about layering in the PNW is that it isn't that cold, but cold and wet enough to make hypothermia all too real. It is easy to over dress, and with the cold humidity you can soak your base layers and end up with a miserable combination. That's why I don't use down.

I was walking yesterday in 50f intermittent light rain with a wp/breathable shell and just a light base layer under and long shorts. I opened all the vents in the shell while climbing uphill and battened down the hatches when my exertion dropped or stopped for photos. Everything around me was wet. When I did stop for a long break, I added a surplus military version of an R2 fleece. Cozy and dry :)

Regarding ponchos and capes: I think they are highly effective rain gear, regardless of the lower cost and weight. Throw in the multi-purpose aspects and they become "free" weight in your system. With the Gatewood Cape, you have rain gear, pack cover and 360 degree shelter coverage for less weight than a typical 2.5 layer rain jacket.

So why doesn't everyone use them? Ponchos can be troublesome in exposed windy conditions or heavy brush. Simply tucking them in with a belt of light line will tame them.

But I think the real reason that ponchos aren't as popular is that they look bad. A Gatewood Cape can look like a wet salad coming down the trail and certainly no fashion statement. Ponchos are a Paleolithic design and about as close to throwing an animal skin over your head as we get in modern times. The bottom line is that they just don't look as pretty as a nice tailored and color coordinated Gore-Tex rain suit. But either cape or poncho will keep the rain at bay and ventilates well. There are no issues with impaired performance due to body oils or being washed in the wrong detergent, or the DWR wetting out. Field repairs are simple.

A GoLite poncho will give head to knees rain protection plus pack cover and a workable emergency shelter for 7oz and $60. I do think you need to add a bivy to use a classic poncho for a primary shelter, but there's nothing better for summer day hike rain protection and backup shelter. You can rig one for a wind break or cook shelter in camp, or add vestibule to a tent , etc. Other than having the head hole, you have a 5x8 tarp to use when you don't need it for rain gear.

Edited by dwambaugh on 05/20/2013 14:20:42 MDT.

Ben Pearre
(fugue137) - MLife
Physics on 05/21/2013 12:27:37 MDT Print View

Fascinating, useful, inspiring: a good read. But if I may take the discussion back to the thread about redefining physics:

As has been pointed out, the relationship between distance hiked and weight is nonlinear, but how close to linear is it if you count system weight rather than just pack weight? It's exciting to talk about getting your pack from 30 lbs down to 10 lbs, but this conveniently ignores the heaviest part of the system: you have NOT reduced your weight by 67%--you've actually just gotten your weight from, e.g., 200 lbs down to 180 lbs--a reduction of 10%. Subjectively it seems that this creates an improvement greater than the 10% suggested by the math (due to the vagaries of biped propulsion, I guess?), but it's not going to reduce your energy expenditure by anything like 66%. What is the real observable improvement? BPL seems the most likely candidate to do a useful study of this subject.

I'd hazard a guess that some desideratum (e.g. distance hiked) is probably nearly linear (or probably affine, but that'd be interesting to know) over a "relevant" range (say, pack weights from 0 to 50 lbs). But it'd be nice to see what that linear-ish range actually is. It would make the whole cost vs. benefit analysis of carrying a tent vs. a tarp, or investing $x in lighter gear, far more compelling!

The human is a source of some difficulty: we change over time, we're probably optimised for whatever weight we normally carry, and if we lose 5 lbs, the way in which we lost it affects our output. So one study might concern keeping people as constant as possible (or averaging over large numbers and controlling for changes in fitness and weight) and measuring distance hiked with varying weights over some "laboratory standard" terrain, and another might be "What's the best way to lower your body weight for backpacking?" Here I suggest focusing on the first one, just because it seems to directly address Will's, um, artistic license.

The data will be extremely noisy, so this would not be a small undertaking. But I think it'd be extremely enlightening (ha).

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: Physics on 05/21/2013 13:05:08 MDT Print View

Not to mention the human body fluctuates by 5-7 pounds daily being relatively sedentary.

Daniel Fish
(daniel@fishfamilypdx.com)

Locale: PDX
... on 05/21/2013 20:38:15 MDT Print View

...

Edited by daniel@fishfamilypdx.com on 06/08/2013 19:07:54 MDT.

William Segraves
(sbill9000) - F - M
Re: Physics on 05/22/2013 06:33:35 MDT Print View

"As has been pointed out, the relationship between distance hiked and weight is nonlinear, but how close to linear is it if you count system weight rather than just pack weight? (snip) I'd hazard a guess that some desideratum (e.g. distance hiked) is probably nearly linear (or probably affine, but that'd be interesting to know) over a "relevant" range (say, pack weights from 0 to 50 lbs)."

I'd make more or less the same guess (~linear wrt system weight), with potential adjustment at the low and high ends, to allow for the possibility that very low weights, carried in a biomechanically efficient manner, may have a lower cost/unit, and that 50 lbs may be higher than the threshold at which most people's biomechanics starts to break down.

It's a very interesting and complex question (by my estimate, an equation describing energy expenditure per unit distance over hilly terrain might have as many as nine terms), and one that's clearly important if one wants to quantify the impact of a given decrease in pack weight.

There's some decent relevant literature out there. If anyone's interested in exploring it with me offline, PM me.

Best,

Bill S.