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rppngears91
May 16, 2009, 7:23 PM
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Ive been searching all over the internet on which knot to use to tie off to a tree/boulder for top roping. Ive taken the classes n all that good stuff, but didnt get shown how to use webbing.
(This post was edited by rppngears91 on May 16, 2009, 8:01 PM)
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fxgranite
May 16, 2009, 8:05 PM
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do a search for "wrap 3 pull 2"
lots of good info out there for tying off to trees
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bill413
May 16, 2009, 11:46 PM
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Don't forget to leave at least 3 inch tails on the knot.
What knot depends a bit on how you set it up - but the water knot is the most basic one for webbing set-ups.
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brownie710
May 17, 2009, 12:49 AM
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water knot and back up each tail using a 1/2 double fisherman's. you'd have to go out of your way to have that fail if tied properly.
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alleyehave
May 17, 2009, 6:20 AM
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rppngears91 wrote: Ive been searching all over the internet on which knot to use to tie off to a tree/boulder for top roping. Ive taken the classes n all that good stuff, but didnt get shown how to use webbing.
a 3 bight or a wrap 3 pull 2 like mentioned are text book. Although i'd have no problem just tying a water knot around a bomber tree/boulder. Like mentioned by someone else, tail length is very important with water knots & 1" webbing, always assess before and after each use...
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summerprophet
May 17, 2009, 6:50 AM
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Wrap 3, pull 2 are INCREDIBLY STRONG, and are commonly used for rigging purposes.
Two issues though:
These are far greater than any forces you are going to generate rockclimbing.
They lack redundancy.
I don't remember the exact numers on a W3P2, but I think they are around the 50 kN range, when we are just looking for 20 kN for climbing.
With the same amount of webbing, you could do two standard loops around the tree, tied independant of each other. and easilly be getting 28kN if they share the load evenly.
A bit more than the OP asked for, and I apoligise for the thread drift.
Overhand follow through has a few differnet names(water knot, tape knot, grass knot), but is by and far the most commonly used for tying webbing.
If this is really a question you need to be asking, I would HIGHLY suggest you have someone look over your system before trusting your life to it.
Best of luck.
(This post was edited by summerprophet on May 18, 2009, 4:25 AM)
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Terry2124
May 18, 2009, 3:22 AM
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rppngears91 wrote: Ive been searching all over the internet on which knot to use to tie off to a tree/boulder for top roping. Ive taken the classes n all that good stuff, but didnt get shown how to use webbing.
The most common knot for webbing is the Water knot. As Bill mentioned leave at least 3 inches of tail. The knot can slip a little and shorten the tails.
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Chinchen
May 18, 2009, 8:22 PM
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Cool site.
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dynosore
May 18, 2009, 8:31 PM
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OK, I always leave tails on my water knots, but has anyone ever actually seen them slip? I haven't. The bigger problem is getting them out after a big load!
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majid_sabet
May 18, 2009, 8:52 PM
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summerprophet wrote: Wrap 3, pull 2 are INCREDIBLY STRONG, and are commonly used for rigging purposes. Two issues though: These are far greater than any forces you are going to generate rockclimbing. They lack redundancy. I don't remember the exact numers on a W3P2, but I think they are around the 50 kN range, when we are just looking for 20 kN for climbing. With the same amount of webbing, you could do two standard loops around the tree, tied independant of each other. and easilly be getting 28kN if they share the load evenly. A bit more than the OP asked for, and I apoligise for the thread drift. Overhand follow through has a few differnet names(water knot, tape knot, grass knot), but is by and far the most commonly used for tying webbing. If this is really a question you need to be asking, I would HIGHLY suggest you have someone look over your system before trusting your life to it. Best of luck.
one inch webbing 4000 -4400 lbs
it is 6 x 4200 lbs on a 1" webbing so @ 25000 lbs with the knot in the front of the anchor.
if the knot is inline with the system then take 30% off 25000 lbs
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acorneau
May 18, 2009, 9:03 PM
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majid_sabet wrote: summerprophet wrote: I don't remember the exact numers on a W3P2, but I think they are around the 50 kN range, when we are just looking for 20 kN for climbing. one inch webbing 4000 -4400 lbs it is 6 x 4200 lbs on a 1" webbing so @ 25000 lbs with the knot in the front of the anchor. if the knot is inline with the system then take 30% off 25000 lbs
Not quite there, Majid.
Wrap 3, Pull 2 gives you 2 loops at the attachment point. 1 loop = 2X the single-strand strength of the material. Assuming your average strength of 4,200lbs. per strand:
4,200 X 2 (looped strength) x 2 (# of loops) = 16,800lbs. (~74.6kN)
That, of course, is using theoretical numbers. I can't imagine that real numbers would play out that high.
(This post was edited by acorneau on May 18, 2009, 9:05 PM)
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summerprophet
May 18, 2009, 9:07 PM
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What?
Majid, how do you know such so many values and fuck up simple math?
A wrap 3 pull 2 has 4 strands sharing the load, not 6,
therefore, 4 x 4200 lbs =16800 lbs = 76 kN
And the very nature of wrap x pull x minimize the stress on the knot, so likely not a full thirty percent strength reduction
76 kN * 0.7 = 53kN therefore, ultimate strength will be greater than 53 kN.
Pretty much what I said allready without taking out a calculator and confusing the OP further.
Again, in this method, you have NO redundancy. This is popular in rigging and technical rescue, due to the high stregth achieved, but both of these have two complete seperate systems (belay and lower).
Open up your mind and use your rigging background and climbing background to be better at both, blindly using one method for the other is irresponsible and potentailly hazardous.
All apologies to the OP regarding this thread drift. I love to give a simple concise answer. Majid likes to be vague and off-topic.
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alleyehave
May 18, 2009, 9:12 PM
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They don't "slip" per se after a large load. They slip over time. Untying a loaded water knot is easy money, take the knot in the palm of both of your hands and roll it while squeezing your palms together hard, comes undone easily. (This exact motion is what causes a water knot to loosen over time as well...)
(This post was edited by alleyehave on May 18, 2009, 9:13 PM)
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majid_sabet
May 18, 2009, 9:22 PM
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acorneau wrote: majid_sabet wrote: summerprophet wrote: I don't remember the exact numers on a W3P2, but I think they are around the 50 kN range, when we are just looking for 20 kN for climbing. one inch webbing 4000 -4400 lbs it is 6 x 4200 lbs on a 1" webbing so @ 25000 lbs with the knot in the front of the anchor. if the knot is inline with the system then take 30% off 25000 lbs Not quite there, Majid. Wrap 3, Pull 2 gives you 2 loops at the attachment point. 1 loop = 2X the single-strand strength of the material. Assuming your average strength of 4,200lbs. per strand: 4,200 X 2 (looped strength) x 2 (# of loops) = 16,800lbs. (~74.6kN) That, of course, is using theoretical numbers. I can't imagine that real numbers would play out that high.
did you see me saying anything about W2,W3 or W4?
I just said 6 strands of webbing x 4200 lbs which gives about 25K lbs.
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heyheyhey
May 18, 2009, 9:30 PM
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I would recommend using a strong-knot.
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majid_sabet
May 18, 2009, 9:32 PM
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summerprophet wrote: What? Majid, how do you know such so many values and fuck up simple math? A wrap 3 pull 2 has 4 strands sharing the load, not 6, therefore, 4 x 4200 lbs =16800 lbs = 76 kN And the very nature of wrap x pull x minimize the stress on the knot, so likely not a full thirty percent strength reduction 76 kN * 0.7 = 53kN therefore, ultimate strength will be greater than 53 kN. Pretty much what I said allready without taking out a calculator and confusing the OP further. Again, in this method, you have NO redundancy. This is popular in rigging and technical rescue, due to the high stregth achieved, but both of these have two complete seperate systems (belay and lower). Open up your mind and use your rigging background and climbing background to be better at both, blindly using one method for the other is irresponsible and potentailly hazardous. All apologies to the OP regarding this thread drift. I love to give a simple concise answer. Majid likes to be vague and off-topic.
We did some testing of W3 and W4 with knot in the front of W and completely loose. After loading the system up to a point where prussic started to smoke, the knot was still loose so I am pretty confident that you could get almost 100% of the 4200 if you place the knot in a right place but most people do not.
Now what would be an interesting to test is to have the knot in the three different layer of Ps and do a test. Like have the knot in P1, P2, or P3 and do a pull test to see where it breaks.
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angry
May 18, 2009, 9:37 PM
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I can think of a half dozen that would work.
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summerprophet
May 18, 2009, 9:37 PM
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This test has been done by Larson/Mauther, and the innermost webbing repeatedly broke at the carabiner.
Literally trapped between a rock and a hard place.
This is why it has been adopted for rigging as a high strength anchor connection.
That being said...... this is a pretty serious thread drift, if you wanna talk shop, start a new thread or PM me, it is a little ridiculous to be discussion professional rigging and testing methods in a beginners forum.
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alleyehave
May 18, 2009, 9:41 PM
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majid_sabet wrote: After loading the system up to a point where prussic started to smoke
What color was the smoke? Was it consistent or intermittent? Did the prussik glow?
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acorneau
May 18, 2009, 9:44 PM
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majid_sabet wrote: did you see me saying anything about W2,W3 or W4? I just said 6 strands of webbing x 4200 lbs which gives about 25K lbs.
Oh, sorry. I thought you were part of the conversation the rest of us are having about W3P2.
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alleyehave
May 18, 2009, 9:50 PM
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I must ask, what do you need 25k lb strength worth of 1" webbing for? Are you hauling a concrete truck? Get a skinnier partner.
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majid_sabet
May 18, 2009, 9:56 PM
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alleyehave wrote: I must ask, what do you need 25k lb strength worth of 1" webbing for? Are you hauling a concrete truck? Get a skinnier partner.
do you know anything about slak lining or highlines anchors ?
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alleyehave
May 18, 2009, 10:02 PM
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I'm sorry, cause I was completely under the impression that the OP was referring to TR setups, I apologize. Do you do a lot of slak lining buddy?
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