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jakedatc
Feb 28, 2006, 2:33 PM
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In reply to: Curt - man, as creator of the "foot belay" are you really throwing rocks in this thread...?
Curt.. ya left a pole in the water man..
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curt
Feb 28, 2006, 3:17 PM
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In reply to: In reply to: ...A Factor 2 fall puts lower peak forces on the climber and belayer (and anchors) than does a Factor 1 fall... This statement is only 33% correct (if by anchor you mean last piece in the factor 1 fall case)...
The "last piece" in a FF = 1 fall situation is not the anchor, so the statement in question is zero percent correct or 100% wrong.
Edited to add (just so I don't appear to be a total asshole) I agree with much of what fingertrouble said in his original post. And, it may be unfair for me to "home in" on this one aspect of his post. Never the less - this statement needs to be corrected.
Curt
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robdotcalm
Feb 28, 2006, 3:45 PM
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fingertrouble wrote:
"A Factor 2 fall puts lower peak forces on the climber and belayer (and anchors) than does a Factor 1 fall.
In hard falls, the rope type has little effect on peak forces, be it one double, a single, or static rope.
These statements are so counter-intuitive that I'd appreciate some evidence for them. In the meantime, I'm not going to start leading on a static rope.
Cheers,
Rob.calm
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dirtineye
Feb 28, 2006, 4:03 PM
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After reading a few of fingertrouble's posts in the thread, and seeing some of his claims, I'm going with Curt.
And I'd rather have a foot belay from Curt than a free copy of Fingertrouble's book any day-- unless I needed to start a fire.
Dumbest thing I have read on rc.com psoted by an allegend non-noob:
In reply to: One piece of secure pro has all the strength you'll ever need (in good rock, but maybe not in choss, ice, or snow). If you intend to place two or more, ask yourself why.
This brilliancy prize winner begs the questions, " Is this piece secure?", and, " How do you know that?".
Best answer to those questions: I don't know. I will never know for sure until it is possibly too late. Better safe than sorry.
Anyone who could write such a thing has apparently never had 'bomber' pieces fail, and thinks that they never make a mistake. Idiot.
And BTW, noggin, the sheet bend and the double sheet bend have NO place in climbing. The sheet bend knots are NOT life support knots. I don't give a fvck what anyone says about it, I've used sheet bends for almost 40 years.
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curt
Feb 28, 2006, 4:20 PM
Post #380 of 915
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In reply to: fingertrouble wrote:
"In hard falls, the rope type has little effect on peak forces, be it one double, a single, or static rope." These statements are so counter-intuitive that I'd appreciate some evidence for them. In the meantime, I'm not going to start leading on a static rope. Cheers, Rob.calm
Yep, that's another real gem. I'm beginning to think we've been trolled.
Curt
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tisar
Feb 28, 2006, 4:39 PM
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In reply to: In reply to: fingertrouble wrote:
"In hard falls, the rope type has little effect on peak forces, be it one double, a single, or static rope." These statements are so counter-intuitive that I'd appreciate some evidence for them. In the meantime, I'm not going to start leading on a static rope. Cheers, Rob.calm Yep, that's another real gem. I'm beginning to think we've been trolled. Curt
It seems to me he's counting in rope slippage at the belay device (according to him preferrably at a munter off the anchor). Since rope slippage in the knot happens at the same force, be it on static or dynamic rope, he'd be right.
But then I'm just guessing here, so I better shut up. :D
- Daniel
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tradklime
Feb 28, 2006, 5:21 PM
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In reply to: It seems to me he's counting in rope slippage at the belay device (according to him preferrably at a munter off the anchor). Since rope slippage in the knot happens at the same force, be it on static or dynamic rope, he'd be right.
My bet is that you are correct. This is not a new idea and has been discussed before.
That said, if you are leading on a static line, there are other variables to consider.
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qtm
Feb 28, 2006, 9:48 PM
Post #383 of 915
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In reply to: In reply to: In reply to: ...A Factor 2 fall puts lower peak forces on the climber and belayer (and anchors) than does a Factor 1 fall... This statement is only 33% correct (if by anchor you mean last piece in the factor 1 fall case)... The "last piece" in a FF = 1 fall situation is not the anchor, so the statement in question is zero percent correct or 100% wrong. Curt
There is one case, where a second climbs faster than the belayer can take in the slack, and the second falls from the anchor. That generates a FF1 fall onto the anchor; any fall from the anchor with slack in the system would.
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curt
Mar 1, 2006, 12:30 AM
Post #385 of 915
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In reply to: In reply to: In reply to: In reply to: ...A Factor 2 fall puts lower peak forces on the climber and belayer (and anchors) than does a Factor 1 fall... This statement is only 33% correct (if by anchor you mean last piece in the factor 1 fall case)... The "last piece" in a FF = 1 fall situation is not the anchor, so the statement in question is zero percent correct or 100% wrong. Curt There is one case, where a second climbs faster than the belayer can take in the slack, and the second falls from the anchor. That generates a FF1 fall onto the anchor; any fall from the anchor with slack in the system would.
No, those types of falls are not fall factor one falls--not even close. Unless you are saying that the belayer took up absolutely zero rope while his second climbed the entire pitch. That's not terribly realistic, in my estimation.
Curt
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knudenoggin
Mar 1, 2006, 1:12 AM
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In reply to: After reading a few of fingertrouble's posts
"1 posts added
since 10 Sep 2005"
Maybe his assertions had you--like most of us--doing double-takes!
In reply to: ... begs the questions, " Is this piece secure?", and, " How do you know that?". Best answer to those questions: I don't know. I will never know for sure until it is possibly too late. Better safe than sorry.
In reply to: And BTW, noggin, the sheet bend and the double sheet bend have NO place in climbing. The sheet bend knots are NOT life support knots. I don't give a fvck what anyone says about it, I've used sheet bends for almost 40 years.
Did you understand how I proposed using them? --'cause that should remove
some concerns about them (security, i.p.). And there's a slight mod. to the structure
I described, in which the Sheet Bend component essentially has no free ends
(i.e., either a lonnnng end that goes to a failed anchor, or a short end going to
another knot).
*kN*
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charlesjmm
Mar 1, 2006, 2:42 AM
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Well Guys, I´ve been trying to address some of the concerns raised by my anchor design (MultiX), namely :
1) Uneven loading of middle placements
2) Length of cord used
3) Excessive use of biners
4) Setup time
5) Equalization in failure mode
I’ve come up with a revised idea : the Modulette, still based on the sliding X with limiter knots as building blocks :
- It uses only two strands per placement and all placements share load with two adjacent placements. This will distribute loads evenly amongst all placements as the power points moves sideways.
- Only two limiter knots are needed for any number of placements. They are placed on the outer legs.
- Only one X is needed and it’s placed on one of the strands joining the outer legs.
- When the outer placements fail, the final configuration will continue to equalize evenly amongst remaining placements.
- When a middle placement fails, there is no extension; the load will be equalized by the 2 outer placements, although the load will be held by only one strand. :?
- Setup time is comparable to a cordellete.
- 20 ft of cord allow to build a 2, 3 and 4 legged anchor.
- The biner used at the power point must be a HMS with wider part facing upwards.
- The knot used to tie the cord should be placed on one of the outer legs.
In pictures ......
http://i49.photobucket.com/...arlosjmm/3LegsMX.jpg
Closeup of the power point :
http://i49.photobucket.com/...m/3LegsMXCloseup.jpg
How to set up the power point. Place HMS biner through all 3 loops :
http://i49.photobucket.com/...jmm/3LegsMXSetup.jpg
In failure mode (center leg) - There is NO extension; resulting load will be equalized by the 2 outer placements, although the resulting load will be sustained by only one strand !
http://i49.photobucket.com/...m/3LegsMXFailCtr.jpg
In failure mode (left leg) - Acceptable extension. Resulting load will be equalized amongst remaining placements.
http://i49.photobucket.com/.../3LegsMXFailLeft.jpg
A four legged anchor :
http://i49.photobucket.com/...arlosjmm/4LegsMX.jpg
Setup tips : (for a detailed graphic explanation, go to page 28)
1) Go about as if building a cordellete.
2) Instead of tying off with an overhand or 8, place the limiter knots on the outer legs.
3) Setup the power point as shown in picture 3 and place the HMS biner through all the loops. Be carefull in choosing the strand joining the outer legs to create the X!
4) You’re set to go…
All your feedback is much appreciated.
CharlesJMM
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kubi
Mar 1, 2006, 3:15 AM
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That's pretty snazzy. How easy is it to adjust the leg lengths for various gear placements?
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justthemaid
Mar 1, 2006, 3:22 AM
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Dingus said to JL (about 10 pgs. ago) "I appreciate your total willingness to revisit this issue, a genuine service" and I can't put it any better, so John (if your still with us) thanks for the research, and I eagerly await the new book.
I have to say I'm totally impressed with all the creative brainstorming I've seen on this thread. I have to admit I've always been a little bothered by the cordolette's tendency to shift to only one piece. I've spent the last few days playing around with everyones ideas. Moose and Gordo- you're both brilliant, but I have to agree with whoever commented that the Mooselette wasn't getting it's due.
My (completely-worthless-because-I-don't-know-sh-t) observations:
Mooselette-Although it's uses may be limited to horizontals with 3 pieces in fairly close proximity. It's fast, a masterpiece of KISS, equalizes well, and with some adjustment you can reduce the inward forces on the outside pieces that some people were worried about. But I'm no engineer- some of you folks with more experience should play with it and post some more opinions. The gordolette also works really well, has less extension, but much more futzing to set up. The equalette (for 4 pieces) got easier with practice.
Keep up the good work everyone. This has been facinating.
Edit: Charlesjmm, that's pretty cool, I'll play with your set up tomorrow.
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justthemaid
Mar 1, 2006, 4:44 PM
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Hey Gordo- (you may already know this). Your gordolette works great to equalize 2 pieces as well as 3. Just clip alternate strands with one biner. In a 4 piece (horizontal) anchor you could make two gordolettes and join them at a power point.
I've been messing with the charles-rig. I'm finding I have to put extra turns in the upper biner of the central line to even it up (which isn't really a big deal I guess.) Unlike the mooselette and gordolette, the charles-rig seems to work in vertical cracks. (yay!). When you move on to a 4 piece anchor I much prefer the equalette which equalizes pieces in closer proximity to each other and has less strands to bind up at the power-point.
I'll keep playing.
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knudenoggin
Mar 1, 2006, 5:26 PM
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In reply to: - When a middle placement fails, there is no extension; the load will be equalized by the 2 outer placements, although the load will be held by only one strand.
One further note:
if center & one outer placement fail, there's a big extension.
*knudeNoggin*
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tradklime
Mar 1, 2006, 5:35 PM
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In reply to: Did you understand how I proposed using them? |
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moose_droppings
Mar 1, 2006, 5:56 PM
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In reply to: Unlike the mooselette and gordolette, the charles-rig seems to work in vertical |
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wideguy
Mar 1, 2006, 7:09 PM
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http://i49.photobucket.com/...arlosjmm/3LegsMX.jpg
I'm interested in opinions on this one too. looks pretty quick and clean, seems to accomplish equalization range of swing is limited by the placement of limiting knots but keeps possible extension low provided you put the X on the right section, as was stated...
I'm a rank n00b... what am I missing?
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knudenoggin
Mar 1, 2006, 9:22 PM
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In reply to: ok.. since no one wanted to do this.. here is my picture recap and either comments of questions on some of them.
within easy reach!
In reply to: I like this one the best however i don't know how to tie that knot with double loops on the bottom and one on top.
necessary for equalization, there will be huge extension; otherwise, if knotted,
there won't be equalization on off-angle loading.
The knot is formed by making a rather long bight (narrow loop) in the bottom
line, folding it back in half (to put bight tip as upwards single eye),
then tying the folded section (4 strands together) in the Fig.8 (or Overhand would
be easier), yielding the double eyes for tie-in.
Yes, it does. But for FOUR anchor points, it equalizes best, most easily.
This is the sort of structure I've described to be implemented in cord (that part
connected directly to the anchor points) & tape (the belayer-side small part).
Note that the UNclipped part spanning the limiter knots should be drawn nearly
taut between them, to greatly reduce extension (not a lot anyway, but ...).
This is esp. obvious/needed for the purple sling; the blue is pretty widely spread,
but the limiter knots should be evened out in lenght to 'biner, and then ... .)
(And note that the anchors are rather widely spaced here, with short attachment,
making for likely wider angles than one would usually have.)
Rather than Glowering's Sliding-X at the belayer-side component,
make that like the other parts: Overhand loopknots for each 'biner (small
eye/loop, just to clip into),
and an unslacked span between the knots that's unclipped. About an equilateral
triangle when set up, and in about a metre of say 8mm, 12mm HMPE tape?!
--could be doubled (i.e., two such pieces) if in doubt (2 8mm would fit a 'binner, anyway).
The un-"X"ed 'biners will slide/adjust most quickly of all systems, IMHO.
Failure of any anchor will give quite limited extension.
*kNoggin*
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knudenoggin
Mar 1, 2006, 9:29 PM
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In reply to: ok.. since no one wanted to do this.. here is my picture recap and either comments of questions on some of them.
within easy reach!
In reply to: I like this one the best however i don't know how to tie that knot with double loops on the bottom and one on top.
necessary for equalization, there will be huge extension; otherwise, if knotted,
there won't be equalization on off-angle loading.
The knot is formed by making a rather long bight (narrow loop) in the bottom
line, folding it back in half (to put bight tip as upwards single eye),
then tying the folded section (4 strands together) in the Fig.8 (or Overhand would
be easier), yielding the double eyes for tie-in.
Yes, it does. But for FOUR anchor points, it equalizes best, most easily.
This is the sort of structure I've described to be implemented in cord (that part
connected directly to the anchor points) & tape (the belayer-side small part).
Note that the UNclipped part spanning the limiter knots should be drawn nearly
taut between them, to greatly reduce extension (not a lot anyway, but ...).
This is esp. obvious/needed for the purple sling; the blue is pretty widely spread,
but the limiter knots should be evened out in lenght to 'biner, and then ... .)
(And note that the anchors are rather widely spaced here, with short attachment,
making for likely wider angles than one would usually have.)
Rather than Glowering's Sliding-X at the belayer-side component,
make that like the other parts: Overhand loopknots for each 'biner (small
eye/loop, just to clip into),
and an unslacked span between the knots that's unclipped. About an equilateral
triangle when set up, and in about a metre of say 8mm, 12mm HMPE tape?!
--could be doubled (i.e., two such pieces) if in doubt (2 8mm would fit a 'binner, anyway).
The un-"X"ed 'biners will slide/adjust most quickly of all systems, IMHO.
Failure of any anchor will give quite limited extension.
*kNoggin*
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cracklover
Mar 1, 2006, 9:48 PM
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Hey Jake,
Nice idea, collecting these all in one place. You might want to edit your post to add in the Mooselette.
In my opinion, the Mooselette is a very successful approach, the only drawback of which is that if the cordelette is cut on one of the outer strands, the anchor fails.
Other than that, I think it's the easiest, it's perfectly equalizing, and has very minimal extension. And if the middle arm gets cut, it's okay.
Here's a diagram:
http://i1.tinypic.com/o6bn9y.jpg
Note that there's a second (unlabeled) limiter knot in the middle strand, just under 'biner "B"
GO
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fingertrouble
Mar 1, 2006, 10:25 PM
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Good work, charlesjmm!
I'd suggest eventually starting a new thread with your latest design, to make it more accessible than buried in this one. Give it a name or start a name contest and pick a winner.
Your design is economical enough that it could be used with a long runner without the limiter knots, if some extension were not a concern. It's undesirable to lose a third of the anchor strength if the middle piece blows, but extension is small and the biner is still held by two strands, each of which sees half the load. It's the remaining placements, not the cord, that would be of concern.
I now retract my previous comment that equalizing 4 equally strong placements is essentially impossible (but stand by my comment that attempting it is tantamount to concluding that none would hold body weight).
Congratulations.
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fingertrouble
Mar 1, 2006, 10:35 PM
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Fair questions, jabtocrag.
You questioned "One piece of secure pro has all the strength you'll ever need..."
In my book I go on about the difference between strength and security. Security to me means that the hardware breaks before it falls out. Admittedly, this is a pedagogical distinction, but you can see from this thread that many climbers are fixated on strength (charlesjmm's equalization efforts are brilliant, but the cordelette hasn't been mentioned much as a means of achieving security). I harp on security instead of strength when designing or teaching anchors. Thinking through the fatal situations I can recall, in every case it seems that though the anchor pulled out the pro didn't break. I've never broken pro myself, but (cough, cough) I've pulled a few pieces as I floated past; I wish they had been more secure.
So maybe I should have excluded RPs and Cliff Hangers, but I'd bet that the main reason rock pro fails is not that it is weak, but that it gets yanked from a direction that wasn't taken into account in building the anchor. Equalization per se frequently might not be the best approach.
And "my calculations suggest a high figure (for peak fall force) might be close to half" of 10 kN."
I said "close to half," deliberately being imprecise because all these calculations, even UIAA measurements, are somewhat imprecise and depend on lots of things (history of the rope, % moisture content, grip strength, blah, blah). In my book I give a figure of 6 to 8 kN. I got that several ways, mainly too tedious to discuss, but here are three simple approaches:
1) Harmston saw zero failures of 10 kN-rated Stoppers, even old ones. Without a lot of statistics that still suggests an upper limit for peak fall forces (on the top anchor) reasonably south of 10 kN. BTW, Chris was examining those Stoppers because they were involved in "incidents," i.e., they pulled out, though none broke.
2) If you work through the Petzl fall force calculator you see that, in a simple system, 5 kN is the highest force that you can achieve on any anchor (selecting a Reverso and a 10.5 mm rope). In my book I have a subchapter on things in the real world than can increase peak forces over what you might expect, and another subchapter on things that will decrease peak forces.
3) As you can also see from the Petzl fall force calculator, when the fall factor is over about .25 you get considerable rope slip in the belay; below that fall factor there's no slip, but the peak force on the top anchor then drops below 5 kN. I don't hear a lot about rope burns or the imperative to wear gloves when belaying; most of the time belayers don't "experience" much rope slip when catching leader falls. This suggests that peak forces on top anchors are 5 kN or thereabouts.
And Rob.calm, you might already be leading on a static rope. Ropes lose a lot of energy absorbing capability as they age or after they have been fallen on repeatedly. Still, don't lead on a static rope unless you can ensure that the fall factor can't exceed 1--but about those gym ropes... For easily accessible evidence, fiddle around with the Petzl web site fall force calculator; it is amazingly informative. You can readily test those two claims that you find counter intuitive (which indeed they are).
Other posters also should check out the Petzl fall force calculator before they flame. It will save us time and them credibility. If anyone has data showing that I, Petzl, John Long, Chris Harmston, Sterling, Beal, and Mammut ropes, and the UIAA are all misguided, post it immediately--it's your ticket to fame.
Craig
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