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maxdacat
Nov 2, 2006, 2:59 PM
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yeah - you're right it's the 10mm one.
i'm fairly happy with 1) as the belay loop offers a fairly broad surface but not so sure about 2) because it's for situations where i may not be backed up.
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justthemaid
Nov 2, 2006, 4:00 PM
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Here's another post from the Lab with more links on girth hitching slings.
There's also a possible alternative listed that's undergone limited testing.
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duncan_s
Nov 3, 2006, 5:38 PM
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Do people really girth hitch slings to slings? The whole idea sends shivers down my spine.
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tomcat
Nov 5, 2006, 2:26 PM
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About a week ago Jim Ewing at Sterling drop tested Dyneema hitched to Spectra in a static test.I thought he would post it here,but has not.The results are eye opening,you can see them at NEClimbs.com
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ridgeclimber
Nov 5, 2006, 3:19 PM
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I wonder whether doubling the sling instead of girth-hitching would create the same problems. My guess is that it would be stronger but still dangerous because of the sharp angle at which the sling would be bent. But I don't have any test data to back me up.
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curt
Nov 5, 2006, 5:01 PM
Post #31 of 44
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In reply to: Do people really girth hitch slings to slings? The whole idea sends shivers down my spine.
Well, let's not become irrational here. The issue of this girth-hitched sling failing is indeed troublesome, but we should not jump to the conclusion that no slings should ever be girth hitched together. That conclusion simply does not follow logically.
Climbers have for years used full length runners tied with water knots--as well as using those which are sewn, without experiencing breakage at the knots. The data show us that these slings should also break under 30% (or so) less force that a sewn runner--but practice demonstrates this really is not something to be overly concerned about.
My personal opinion, which may or may not be proven out by additional testing, is that really thin slings should probably not be girth hitched together--and that when thicker slings are used (say 9/16" or so) girth-hitching them together is much less problematic.
Curt
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healyje
Nov 6, 2006, 10:55 PM
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In reply to: i would like to add myself as an interested party as far as this question is concerned... i currently have my dyneema slings cloved to one of the biners in my quickdraws, it is so nice that way, very easy to extend when trick-tripled, but i really would like to know about any safety concerns with this setup
I have to say I think this is a bad idea in general from a couple of counts both on the girth hitching and the wear on the girth hitch from the free strands when unextended. Beyond [some] convenience I'd say the minuses far outweigh the pluses in this practice.
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dbarandiaran
Nov 15, 2006, 8:08 PM
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[reply][quote]i would like to add myself as an interested party as far as this question is concerned... i currently have my dyneema slings cloved to one of the biners in my quickdraws, it is so nice that way, very easy to extend when trick-tripled, but i really would like to know about any safety concerns with this setup[/quote]
I have to say I think this is a bad idea in general from a couple of counts both on the girth hitching and the wear on the girth hitch from the free strands when unextended. Beyond [some] convenience I'd say the minuses far outweigh the pluses in this practice.[/reply]
my slings are not girth hitched, they are clove hitched. my question was in regards to clove hitches...
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konaboy
Nov 15, 2006, 9:12 PM
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In reply to: my slings are not girth hitched, they are clove hitched. my question was in regards to clove hitches...
As was mine. If you clove hitch the mammut slings onto a biner and take a look at how they lay atop one another, it appears that the slings are pretty much face to face. I agree with dbarandiaran that clove hitching one side of a tripled up alpine draw makes it much nicer to work with for various reasons. I'm quite interested in the numbers from a pull test with the mammut slings attached to a biner in such a way.
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deadhorse
Dec 5, 2006, 10:02 PM
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cloves aren't nearly as dangerous for the sling BEING cloved, because they dont fold over themselves, just constrict (remember a clove is one turn away from a constrictor hitch) What they are hitched to is a bit different story however. I use cloves when fixing a sling to something to get a grip on it.
I don't see why girth hitches are being used at all, unless you're short of slings and HAVE to, I really stay away from them. There is an improved girth hitch (it's got an extra wrap or two in it somehow) that I came across once. maybe planetfear? anyways, strength tested it did much much better than a girth.
feed the whole thing through and clip both ends, or use sling-biner-sling setup. ugly, but much safer.
but still, very suprised body weight would do that. There had to be a vector at work, or defect.
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Alpenstock
Dec 8, 2006, 10:28 PM
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Thanks for the heads up. I use Mammut's 8mm dyneema slings for leading with trad gear. Sometimes, when attaching the sling to pro, I get a girth hitch at one of the biners. Til now, I just found it annoying - sometimes I'd straighten it up and sometimes I'd just leave it alone. From now on, I'll make darn sure not to have a girth hitch in the system!!!
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kaivalyavarma
Dec 29, 2006, 9:42 PM
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knudenoggin
Dec 30, 2006, 6:11 PM
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kaivalyavarma wrote: The reason behind breaking could be the linkage of Nylon to Nylon. Secondly Girth hitch is similar to Reef knot. If Reef knot reduces the breaking strength of rope to 65% then the Girth Hitch will also reduce the breaking strength of the rope. I have came across similar failure of webbing.
most folks indeed oriented the so-called "Girth H." to resemble the Reef knot
(though in the flat material it naturally takes an asymmetric form in terms
of the cross section--ONE sling bends around the other, which is straight),
the broken one pictured in this thread was indeed more like the Girth/Cow
Hitch made to a rigid object, where the hitching material bends back around
itself!
In any case, this unseemly form was one of those tested recently; and the
other, asymmetric square form was tested by BD as shown on Climberware's
site. --no shocking weaknesses found in any case.
Frankly, the sharp, just-outside-of-the-knot cut pictured here looks like careful
sabotage with a knife!
It's been a couple months since Mammut promised to investigate this;
what's the latest?
*knudeNoggin*
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krosbakken
Dec 31, 2006, 6:40 PM
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So should people be worried with all webbing girth hitched or just the 8 mm webbing.
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knudenoggin
Jan 1, 2007, 1:21 AM
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In reply to: I guess I am lost. I have always connected slings together with the only knot I know of. I am assuming that is what a girth hitch is?
knots)--denotes various geometricly distinct cordage structures.
.:. So, it is they; and they is!
Please confer http://www.bdel.com/...p_archive.php#110906
which is a nice report done by Kolin Powick on various things; scroll down a
bit to his November sling-2-sling testing.
NB: Kolin does NOT test one (common/natural, I'd think) form of the "Girth Hitch";
he does however test the (surprising/unnatural, IMO) form shown by the OP.
COMPARE:
http://www.climerware.com/knot6.gif
http://www.bdel.com/...s/scene/image012.gif
One might note that using the "Girth Hitch" in the form of the OP is more akin
to that linking tested on the Climerware site that got the lowest strength (not
at all surprising to me; what surprises me is that he was!). [nb: 'climer', not 'climber']
Kolin also observes:
In reply to: During one test a girth hitch slipped to a strop bend —this sample ultimately went many drops more than as if it had been girth hitched.
dressing to achieve; rather, I believe that the case noted here was in fact the naturally
occurring form of the knot shown by Climerware cited above--the collar of the Girth
H. slipped back over the hitched-to sling from its position around itself (there really is no
way to slip into the symmetric form of his Strop bend).
Below is the sort of nonsense that shouldn't arise, with some circumspection:
In reply to: From the look of the photo and where the failure occured I'd suspect that ANY knot in that thin a Dyneema sling could produce a similar failure. I fully expected to see the failure in the sling that was girth hitched to, not in the one that had the girth hitch tied in it.
observation has been made: put the hitch in the STRONGER material!
As for "looking at the photo", look more closely--to wit:
In reply to: It's also worth noting that the cut of his narrow sling appears to be very clean [i.e., sharp/straight]; on all of the tests we performed, there was much fraying, etc of the ends after the breakage. Also, all of our narrow web failures went diagonally across the web, whereas John's appears to be very perpendicular to the web. Could it be possible that there was already a slight "nick" in his thin web which allowed the break propagation during loading?
ropes (also tape?) can fail at lower loads when partially suddenly cut UNDER LOAD,
with a rapid propagation of sorts; but the same degree of cutting didn't cause a break
when the cutting preceded the loading.
In reply to: So should people be worried with all webbing girth hitched or just the 8 mm webbing.
beliefs take hold quickly via the Net.)-:
Note that for ALL of the sling-2-sling combinations tried by Kolin, including SIXmm
dental floss--both to a like sling, and to 11/16" nylon--, at least TWO severe test drops
(severe, FF ~2(!)--highly unlikely in the field) were held.
Now, what was your worry?
I surmise that a quite simple knotting redresses concerns both of strength
and ease of untying: lay sling_A over the end (about 8" in from (measure
by whatever tool works 4 U :o) ) of sling_B so that A hang down;
bring the (far) end of A up through B;
then open it around B to hang down again;
repeat; repeat again (and once more for four?). It might be best to set-dress
the joint so that each sling does some wrapping, vs. one being pretty straight
(likely B) and the hitched-to-it one (A) making all the wraps. (Note that this
is NOT the "Climer Sling Hitch", in which each sling makes a full wrap around
the other; here, each sling's sides wrap each other--1-on-1, vs. 2-around-2.)
>>> YET TO BE TESTED
*knudeNoggin*
(This post was edited by knudenoggin on Jan 9, 2007, 9:14 PM)
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kaivalyavarma
Jan 9, 2007, 6:53 PM
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Did you found an alternative to Girth Hitch? Please let me know the findings.
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jeremy11
Jan 9, 2007, 7:53 PM
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dbarandiaran wrote: [reply][quote]i would like to add myself as an interested party as far as this question is concerned... i currently have my dyneema slings cloved to one of the biners in my quickdraws, it is so nice that way, very easy to extend when trick-tripled, but i really would like to know about any safety concerns with this setup[/quote] I have to say I think this is a bad idea in general from a couple of counts both on the girth hitching and the wear on the girth hitch from the free strands when unextended. Beyond [some] convenience I'd say the minuses far outweigh the pluses in this practice.[/reply] my slings are not girth hitched, they are clove hitched. my question was in regards to clove hitches...
I use a cross section of bike tube as a rubber band to hold the top biner in place on trad draws (and cams). it gives you the full length of the sling and you dont have to ponder about a clove hitch holding. It makes it way easier to keep the trad draw tidy and easy to deploy.
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thedejongs
Jan 22, 2007, 9:18 PM
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It's taken some time to do a full and careful investigation. I've attached a summary from Mammut dated January 10,2007. The full report will be posted on the Mammut website within the week.
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Attachments:
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8mm Sling Report Summary.pdf
(60.8 KB)
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knudenoggin
Jan 24, 2007, 1:54 AM
Post #44 of 44
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The Mammut report confirms some of our assessments of the cut sling
--i.e., that it was cut, not broken by any sort of loading or fatigure
from use or chemical degradation.
Now, we really should wonder how/why:
(1) Is the OP playing a hoax on us?
(2) Could this cut be made while loaded?
(3) ... or if not, then it was perhaps quite carefully cut only 98%
so as to hide that fact, with the part maybe pushed just behind
the collar of the Girth Hitch--pulled out a bit on loading.
(4) BUT the OP states he was on rappel, ... --i.e., weighting
the line! Could the 2% of HMPE uncut hold that weight for
the duration (i.e., could it have been pre-cut instead of cut WHILE
he was loading it)?
(5) OTOH, would a cut under his rapping loading be so straight?
--I guess a quick slice w/sharp knife would do so, but note how
un-frayed that end is (I'm wondering at whether one should
expect some evidence of it flying apart if cut loaded)!?
In short, though we should feel relieved about the scares advanced
re knotting HMPE dental floss etc., the fact is that this report was
made to the forums and to the vendor, at no insignificant concern
to us all; and if not an unfunny hoax, the guy on the sharp end
of this cordage must be wondering how unfunny the prank
of sling-cutting was, or ... ?!?!
But it seems that this sling couldn't be cut where it was in situ
w/o notice that there was a 2nd anchor point, which gives some
further things to wonder about.
*knudeNoggin*
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