BEWARE of Spectra Cordelete!!

[Ibex]

Hey folks,

I posted this in the "Cordelete Retirement" a few days ago, but I thought it was important enough to give it its own thread. If you use spectra, or any of the high strenght techy 5.5mm cords for cordelete, you NEED to read this.

Give a read to:

http://www.fishproducts.com/tech/High_Strength_Cord.pdf

Pay special attention to:

1) Fatigue life tests

2) Drop tests

Kudos to Moyer et al. who put this paper together.

[ 12-11-2001: Message edited by: Ibex ]

[Cpt.Caveman]

Good thing I never used it but once. I nearly always used nylon webbing or my rope......

[freeclimb9]

dude, the sky ain't fallin.

There is no new qualitative information provided in that paper. Cycle testing was performed by Bluewater ropes in the late eighties when they first started weaving Spectra from Allied Signal into ropes and webbing. In that series of tests, the cording was cycled over a rotating bar about the circumferance of a carabiner; kevlar shredded itself, nylon failed near bodyweight after a couple hundred thousand cycles, and the cycling motor burned out after a million cycles on the spectra and it was still strong. In this latest set of tests, the method of cycling differed greatly (recall that the cord, or webbing, was put through a hole in a block which was rotated 180 degrees --the radius of curvature of the edge of the block was NOT specified, but was probably very sharp. Additionally, the diameter of the hole is NOT specifed. No standard deviations are given either, so who knows how reproducable the results are). It's intuitive that cording and webbing that deforms will fare the best due to the greater surface area exposed to the edge which lessens the pressure on the fibers. That's what the test results show: the webbing did great; Bluewater spectra cord did fine since they weave their cordage fairly loose (to allow it to deform); the "extremely stiff" (as noted in the paper) BD Gemini and Maxim Spectra A started to lose strength quickly; the Sterling 7mm cord did great (I'm not familiar with that cord, but I'd lay money on it being soft and easy to deform --NOT stiff, in other words). The dynamic fall tests just confirmed that the cord, or webbing, failed at, or near, the quoted tensile strength.

The tests essentially showed that bending a stiff cord over a sharp edge weakens it (and over time will cut it). No shit. That type of cycling would be rare to encounter while climbing unless you're trying to cut the cord intentionally.

I don't see any reason to retire your spectra cordelette.

I'll add that if you've been using a cordelette for a belay (no matter what they're made of) when full strength runners and the main rope are available to equalize the anchors with, you need to rethink your strategy.

ciao

[Dru]

I got some of that Spectra-A stuff that came out pretty good in the test but when I belay Caveman I will switch to nylon because of the chance the anchor will get loaded.

[Cpt.Caveman]

I am the anchor Dru

[Terminal_Gravity]

Feel the Anchor, Know the Anchor, Be the Anchor.

[Neri]

Great topic thanx for the info watch out for the hype I Guess

[Dru]

quote:

---

Originally posted by Cpt.Caveman:

I am the anchor Dru

---

I thought you were the Walrus! 'Cause I am the Eggman! goo goo ga joob.

[erik]

beware of red herrings!!!!!

i just read a study that said almost 40% of auto accidents in some way involve a cell phone. thank god i don't use one. so read do not use cell phone, you will die in your car.

[Ibex]

I just checked outside to be sure, and freeclimb9 was correct, the sky is not falling, but lucky for us, the snow finally is.

Peace my friend, I am not trying to use this as a forum for advancing my ego, rather I am trying to positively contribute to the body of climbing knowledge by sharing the information I have found.

I did not know about the cycle tests performed by BW, but I must say the hypothesis you draw regarding loosely woven cord more resembling webbing is an intuitive one.

You are right that they did not specify the radius of edge that they flexed the cord over, and they commited a statistical "no-no" with this particular test of using a sample size of one.

I dont see this paper as an "end all" trestise on the topic, complete with 100% statistical reproducibility. Here is what I think it does show: (be forewarned this is just IMHO )

- The fatigue properties of these materials IS important. You mention that b/c we load things over carabiners, not sharp edges we cant take anything from this. I disagree. The forces applied in the real world are much heavier than the token 40 lb (i'll assume mass ) hung off of them in the Moyer test. Granted this is comparing apples and oranges, but they are still fruit. The IS significant indication that the fatigue properties for techy cords are poorer than their nylon counterparts, even in the more loosely woven techy cords. I did not say throw them in the trash can, but I think there is "significant indication"

-The drop test looks at the worst case scenario of a nasty whipper, statically held, and a directional through the belay. You are correct that it mainly validates the strength of the static tests. The point that I think it (and the graph above it) illustrate (I didnt say prove) is that even when the cord is brand new, and you are using some fatty ancient 11mm rope that doesnt stretch much, and belaying through the anchor, it is "plausible" to break several of these with repeated high impact force falls. Note the combination of rising impact forces, and belaying through the anchor. These factors are tested separately here, but it is plausable to *infer* the effects of both when combined. Which is that several of these would break.

-Another VERY important area is the knot efficiencies. Because of techy-cord's high strength, some people have tried making their own webolette style; single strand cord with 2 figure-8 knots in the ends. This test shows that this is ludicrous ,given the poor knot efficiency, with some of these cords. If you download the data, from his webiste, he DOES publish the individual data points, mean, AND stdev.

-Now if you think these tests are "unrealistic of what would ever happen in the real world" you are right. BUT(!), so are UIAA drop tests!!! The idea is to look at the worst case scenario (or even beyond it), set a standard, and then we can sleep better at night because we know we will never stress our gear as harshly as theses tests do. ALL they are trying to do is "set the bar" so to speak in terms of cordelete performance. Dont dismiss it because you think it is a bit unrealistic.

-I dont know anything about the BW test back in the day, but the folks who ran this test are industry professionals. Harmston is the BD quality assurance manager (with a LOT of research experience), and Moyer has done extensive testing on several other rescue related topics. They are probably just as qualified as the folks that BW had on staff running their tests a few years back. So what's the point...? Nobody is infalible, and these guys arent complete idiots. Even if you don't like all of their methodology, there is still a lot to be learned from their study; even if you feel it is redundant and of lesser quality or applicability than the BW study.

-If you want to help improve the populous understanding of this issue, post up the BW test info. All I am trying to do is share what I have found. If you have some ideas, write them up, be polite, and post them. I'll be glad to listen to what you have to say.

-If you aren't a cordelete/webolete fan, that's fine Many people arent. The fact of the matter is that a LOT of people are, and this is important information that pertains to them.

Everyone has to make a PERSONAL decision regarding the levels of safety they wish to maintain while practicing the sport. We must make decisions with imperfect information. This paper illustrates some things (and proves others) and only serves to better climbers' understanding of their equipment and make educated choices.

Saying "Beware of Spectra Cordelete" is like saying "Beward of Dog". Its no guarantee that you are going to get bit, simply a bit of information you might not pick up from simply looking at rover and guessing what his disposition is.

I need one of these

Cheers

Shawn

[ 12-11-2001: Message edited by: Ibex ]

[chriss]

Had to look at the data since all the arguements over what it said or didn't say.

It seems, to me, that 1" tube web is the way to go.

chris

[Dru]

but 1" tube is bulky and heavy! (sound of argument circling around and biting its own tail)

[Dru]

on the subject of dangerous gear any cams or pins, nuts or biners that have ever taken a SMALL fall (like you dropped them on the floor)are truly dangerous and should be retired. likewise any gear that was ever in the trunk of your car, because of possible battery acid fumes weakening the materials.

please send all such dangeous gear to me. I can dispose of it safely.

[dan_e]

Check out this site for cordellete testing:

Great info. on this can be found here:

http://www.xmission.com/~tmoyer/testing/

The best, most complete info. I've seen yet.

Dan E.

[Dru]

scary scary spectra cordelette

scary scary water knot

scary scary euro death knot? american triangle? slackline? spectre? tied off screw? copperhead?

[Cpt.Caveman]

I wonder what them old timers thought with theri gear. Sketchy !

[freak]

dude I havent use cordalette since it failed in a toprope situation, got cut over a not so sharp egde, basicaly it wore through after we had been toproping a really steep erratic basalt boulder with lots of little edges and stuff. nic

[freeclimb9]

was it Dirty Harry, or The Man with No Name, that said "A man's got to know his limitations"?

The limitations of his gear are also important to know.

[chriss]

Check BD's page on webb and cord...

http://www.bdel.com/rockclimbing/ropes-etc_accessory-cord.html

They have... 7mm cord 9.3 KN 31 grams/meterand (less than 1 inch, though)... 18 mm webb 13.3 KN 27.9 grams/meter

stronger and lighter.

chris

[Dru]

i just saw some anonymous person reading this thread...

 

thought i would update it

 

how many people have died from spectra cordellete breaking in the last year and a half?

[Attitude]

erik said:i just read a study that said almost 40% of auto accidents in some way involve a cell phone. thank god i don't use one. so read do not use cell phone, you will die in your car.

People are still regularly dying in auto accidents caused by cell phone wielding drivers, though.

[erik]

ATTITUDE

 

thats what i said!!

 

thanks for clairfying myself for me!!

 

 

[Dustin_B]

freeclimb9 said:

I'll add that if you've been using a cordelette for a belay when full strength runners and the main rope are available to equalize the anchors with, you need to rethink your strategy.

Then what do you use a cordelette for???

[Bronco]

when you're at the end of the rope and need to sling a big ass boulder. I don't make a habit of carrying one at the crags, except castle rock or other places I know I'll be slinging a big boulder. Mainly for mountain tomfoolery.

[freeclimb9]

Dustin_B said:

freeclimb9 said:

I'll add that if you've been using a cordelette for a belay when full strength runners and the main rope are available to equalize the anchors with, you need to rethink your strategy.

Then what do you use a cordelette for???

I don't use one. For me, it'd be like carrying a #6 tricam, or other stuff I'd rarely use. But I do like to carry 15 shoulder slings on longer routes. BTW, this thread is old.