Best Anchor Chain: Metolius PAS vs. Bluewater Titan Loop vs. Sterling Chain Reactor

bevans wrote: ... It's simple, avoid putting yourself in situations where you might fall directly onto a sling...whether it's nylon or spectra. Every climber should know this.

Well said. And I agree with everyone else that just using a couple of shoulder length slings is the cheapest and probably best way to set up tethers. I'll keep my spectra daisey chain and continue to use one trad draw from the rack as my backup as I always do now. I like two attachment points on anchor cleaning and rappels.

John Wilder wrote: That's a 30% reduction in strength, or a 70% knot efficiency...

Er, yeah. Right math, wrong words. Thanks for the correction =)

Toby/Bevans--

Toby--you're using "loops" on one side of the purcell, not both. that's my prob with it--at one point you're on a single (knotted) loop of cord, so you're at 70% strength on single-strand (usually) 6mm cord...too close to failing point for a factor 2 for a avg sized dude.

Bevans--the data are out there. contact mike gibbs at rigging for rescue in ouray, and i did extensive research for a piece i contributed to Rock&Ice...there IS reason to be extremely wary of spectra used in these situations...

i agree with all of you: you SHOULD NEVER put yourself in a position to factor 2 onto your anchor...but the point is, it happens and especially those less geeked-out/attentive than we are are liable to do it...that said, the rope's your best choice, then that Beal assembly, then nylon...spectra MUST have a dynamic component to the system to be safe, and relying on one's body to be the dynamic component is asking for a serious problem, high off the ground....yuck!

good points, all, though. thanks for the perspectives and info...

As always, sage words from Rich Goldstone (I still use a tether in certain situations but am very cognizant or the hazards involved):

It is certainly old news that falls onto static materials can produce catastrophically high forces. The UIAA journal had an account a number of years ago of a factor-two fall on a quickdraw causing one of its carabiners to break; the climber decked. At that time, Petzl subjected some of its standard nylon runners to factor-2 falls and got maximum impact loads of 18 kN, well above the 12 kN so-called maximum acceptable load for humans (in a parachute harness, I think).

Of course, we tend to ignore the extensive European knowledge base, so the subject had to be revived by Mike Gibbs, at first in 2002---see

marski.org/index2.php?optio…

caves.org/section/vertical/…

These tests, in which the Metolius PAS broke in factor-1.25 falls, may have been discounted by even the climbers who knew of them because of the 100 kg rescue-appropriate weights used. (It may be of interest to note that OSHA regulations for "positioning device systems" for a single individual require them to withstand a factor-2 fall with a 250 lb (113 kg) weight.)

The Gibbs tests also indicated that a Purcell prussik tied in 6 mm or 7mm cord was a far better option. Given the moderate adjustability of the Purcell prussik tether, it remains a better solution than the single-length Beal tethers. With regard to the sewn fixed-length tethers mentioned by orsemaj, it is worth reading the French study

caves.org/section/vertical/….

Their conclusion is that a tether made of the same rope material but knotted at both ends is a significantly better load limiter---the tightening of the knots has a significant energy-absorbing effect. In other words, the homemade version is more effective than the commercial version.

Getting back to HMPE tethers, a few years after the Gibbs reports, Sterling ropes replicated the breaking of the PAS, but this time with 80 kg weights and a factor-2 fall. In response, they brought out a nylon PAS clone, the Chain Reactor, which will hold several factor-2 falls without breaking (which does not mean, as in the quickdraw accident, that something else will not break).

Nobody on or off-line made a fuss about Metolius continuing, as they do to this day, marketing the PAs---and it is a dedicated tether, not a sling whose primary purpose is to extend protection. The SuperTopo site recommends the PAS without acknowledging any of the breakage results and does not even mention the Chain Reactor. The comments I posted to that review were, last time I looked, totally ignored by other posters. So I think it is fair to say that there is little to no sense of urgency in the climbing community about whether or not HMPE materials are suitable for tethers.

DMM was several years late to this particular game, and their results were already known. As a result, suddenly singling out BD makes little sense; there are many purveyors of dyneema slings and, in any case, tethering is hardly the primary function for climbing runners, which work just fine used as runners.

As to the question of whether dyneema slings or the PAS will really break with a human rather than 80kg of steel on the other end, I think the honest current answer is that we don't know. Various tests have shown that human weights do not produce as high a maximum impact load in fall situations, so the braking of dyneema slings with an 80 kg steel weight does not necessarily mean that the sling will break with an 80 kg human. Some people are already certain HMPE slings won't break with human weights, but I for one don't know what data their certitude is based on.

The explanation that humans are squishy and harnesses "give" don't come close to explaining the claimed discrepancies in impact loads. My guess is that humans are a collection of jointed weights which are not stopped at the same instant and are not all moving downwards at the moment of impact. More and more realistic test dummies are being produced, and are beginning to find their way into the testing of climbing materials, so we should expect some revised test results realtively soon.

so what to do in the meantime? I think that focusing on the hypothetical breaking of HMPE materials under human factor-2 falls is the wrong emphasis. The real point is that using either HMPE or nylon tethers in situations where they might be called on to absorb fall energy will produce dangerously high loads to the system and the body---something is likely to break, even if it isn't the tether itself. HMPE is worse, but nylon runners are still plenty bad enough. And this if for factor-1 falls, which are a potential common result of a tethered fall.

So, slngs or tethers or daisy's are a truly inferior approach if a climbing rope is available for anchoring.

If a climbing rope is not available, as in rappelling situations, then it is really important for the climber to remain below the anchor with as little slack as possible in the tether. Moving above the anchor, which of course sometimes has to be done, should be treated with the same caution and attention as if one was free-soloing, because breakage or not, you are in a serious danger zone. - Rich Goldstone

climber.co.uk/categories/ar…

factor 2 fall on a dyneema daisy test by CAMP ... not that i recommend using one

everyone will eventually find points were theyll need to introduce a bit of slack on an anchor sling ... the trick is to keep the slack minimal, brief, dont let go with yr arm and preferably with some kinda of backup

as an example today at the end of each rope solo pitch i clip my pas to the anchor, i need to pull up a bit to release the microascender and put the weight on PAS, however im backed up by the rope cloved to my belay loop ... not that falling on a PAS or any anchor sling is a good idea with any kind of backup

coppolillo wrote:Bevans--the data are out there. contact mike gibbs at rigging for rescue in ouray, and i did extensive research for a piece i contributed to Rock&Ice...there IS reason to be extremely wary of spectra used in these situations...

Thanks for the reference. I am aware of much of the data. I do not agree that the "risks" associated with using spectra material require me to be "extremely wary" to any extent greater than the rest of my kit. I'll continue to utilize spectra in appropriate situations with appropriate recognition of its limitations - as I do for every piece of gear.

I don't crossload my 'biners. I don't top rope thru a nylon sling. I don't no-hands belay with my gri gri. There are appropriate uses and limits to every piece of gear. Use them appropriately and they are perfectly safe and adequate.

coppolillo wrote:spectra MUST have a dynamic component to the system to be safe

If I am hanging on my spectra slings I have no need for a dynamic component. Any need for a dynamic component reflects improper use of that piece of gear.

That said, I tie in/anchor with my rope. And yes...we don't live in a perfect world where movement around an anchor is never needed. Duly noted.

cheers.

John Wilder wrote:having been blown off my stance in high winds and statically falling onto my anchor once upon a time, i'd say the chances aren't zero. if you're going to use something other than the rope (i use the chain reactor on routes i know i'm rappelling), make damn sure its nylon- dyneema fails in a high FF situation, which isnt impossible, so why on earth you would use it is beyond me.

I don't think any aftermarket personal anchor systems are purely Dyneema/Spectra. I believe both the older Metolius and Blue Water use dyneema/nylon weaves, and I believe your Sterling is all nylon.

One would have to use a runner for the pure dyneema/no stretch/high FF situations.

Kyle Christie wrote: I don't think any aftermarket personal anchor systems are purely Dyneema/Spectra. I believe both the older Metolius and Blue Water use dyneema/nylon weaves, and I believe your Sterling is all nylon. One would have to use a runner for the pure dyneema/no stretch/high FF situations.

There isn´t any climbing equipment that is pure Dyneema/Spectra that I´ve seen or am aware of. It is always a nylon hybrid, runners included.
The tapes I´ve tested and ones I have the specs for all have an extension of around half that of pure nylon and the impact forces are doubled.

I personally just clip directly to the anchors with one of THESE babies. Foot skates off ledge = gentle ride all the way down. The ultimate in dynamic catches!

Also very funny to clip to leader's tag loop when he's on the way up. "What the hell is so heavy on my harness, geeeeeze."

metcalfd wrote:I'm a sport/trad climber looking on buying an anchor chain to use while setting up a TR or getting in position to belay a follower. I've researched a little on the failure properties of spectra/dyneema and nylon but am not sure if I'd really have to worry about taking a factor 1 or 2 fall on it in the situations that I anticipate using it in. What would be the best option for my situation?

Forget the other crap and try what I describe here: mountainproject.com/v/a-gre…

coppolillo wrote:Toby/Bevans-- Toby--you're using "loops" on one side of the purcell, not both. that's my prob with it--at one point you're on a single (knotted) loop of cord, so you're at 70% strength on single-strand (usually) 6mm cord...

There are two loops on the anchor side, yes, and a single loop on the harness side, as you admit. But it is still a loop. At no point using a Purcell are you ever putting tension on a single strand of cord.

To put it differently: a Purcell is attached to your harness with a girth hitch. How do you tie a girth hitch with a single strand of cord?

Maybe we're talking about two different things? It's certainly possible to tie a purcell with a single strand on the harness side and a figure-eight attachment to your harness. If that's what you're envisioning then I agree it's not the best idea!

edit: I just realized something. You know that when you have a loop of cord or webbing, formed by a single continuous piece, and you bend it around something (say, a carabiner or the tie-in points on your harness) you roughly double the holding power of the entire system, right?

Toby-Bevans--you guys are totally right about the loop/cord thing--I'm a crackhead and was using the single-stand strength...and therefore freaking myself out! Owe you guys a beer.

Whoever posted the Goldstone quote, thanks, good info. I don't know that guy's research/writing.

I'll def check out using a Purcell in rap/anchor situations...

As for spectra/dyneema, I'd still caution folks using it...sounds like most people on this string are smart/savvy with it, but I still worry about less experienced climbers using it "because it's so light."

Oh, and is this the longest string on MP without anyone insulting anyone else? A triumph!

Thanks all, hope you're all doing well and climbing.....RC

coppolillo wrote:Toby-Bevans--you guys are totally right about the loop/cord thing--I'm a crackhead and was using the single-stand strength...and therefore freaking myself out! Owe you guys a beer.

I knew we were just having some communication difficulties! Cheers =)

T.Dailey wrote:+1 for the Purcell. I bought a double length Mammut sling and used that for my Purcell. It was really slick at first and the prusik would slide pretty easily, but now that it's lost that factory "sheen" It works great. On multi-pitch climbs, I'll clove hitch the rope to whatever master point I've made and back it up by clipping either the "top shelf" or most bomber piece with the Purcell.

I remember when I saw my boy T. Dailey bust out his fancy extendable Purcell. I thought, wait, how did you? Dang that's neat.

Is it me or is he the only one that commented on redundancy. The only other discussion is people concerned with a single strand of cord through tie in points.

It seems like most are using a single PAS, Purcell, daisy etc... I've always felt uneasy when hanging off an anchor solely on my single PAS and back it up 60% of the time every time.

Rope. Runner(s) girth hitched to harness. Skinny dental floss DIEneema is fine.

I use the PMI verglas -- thing is the bomb!