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blueeyedclimber
Mar 3, 2009, 12:41 AM
Post #26 of 43
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summerprophet wrote: Sigh...... I give up trying to explain this. The OP got his answer long ago.
 Me too.
When you said second rope, did you mean a second leg (as in for a top rope anchor)? If so, you confused me. Text without pics can sometimes be a little confusing. In any case, I guess this has absolutely nothing to do with the op. Successful thread drift 
Josh
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kriso9tails
Mar 3, 2009, 2:14 AM
Post #27 of 43
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blueeyedclimber wrote: summerprophet wrote: I give up trying to explain this. Me too.
Does that mean it's too late to chime in with some alpine butterfly nonsense then?
(This post was edited by kriso9tails on Mar 3, 2009, 6:34 AM)
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knudenoggin
Mar 3, 2009, 5:40 AM
Post #28 of 43
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In reply to: Two independent figure 8's are redundant whereas [bunny ears] is not.
The OP is talking about suspending a rope from two bolts;
how does making two eye knots give any redundancy over
one knot with two eyes? At least, all I can understand this
to mean is that the endmost knot leads to the 2nd (which
is clipped to a 2nd anchor), and, yes, in that case the
1st knot (but NOT the 2nd) could be disintegrated.
(It also means that the 1st knot isn't taking any load unless
the 2nd anchor fails, or the anchors are vertically aligned.)
But the structure you're describing sounds like what has been
advanced for TR anchors, where there are TWO lines leading
away from a powerpoint comprising the the two eyeknots,
and each thus is independent of the other. Which is what you
later describe:
In reply to: It's actually two separate bights side by side. This is commonly used for a power point when using static line to set up a toprope.
a bight (hence, a fully duplicated bowline).
Bowline WITH a bight
http://www.postimage.org/image.php?v=gx1cEm_9
(The topmost knot is a sort of symmetric Fig.8 directional eyeknot.
The black cord in center marks the end-bight (returning into the knot).
The black rope in bottom highlights the end that can pull out if the
eye it feeds is cut; otherwise, it takes a very nice-looking, gradual
bend around the 4 diameters of the eyelegs, and I figure will be
strong, thus. The lower photo turns the knot 90deg. to show this
nice mild curvature; and black cord is laid in the strand's path.)
http://www.postimage.org/image.php?v=Pq2BJlsi
Back to Bunny Ears, ...
In reply to: [Luebben, p,220]"It is not truly redundant, because if one loop severs, the other loop may slip through the knot, causing anchor failure."
I don't buy this. Maybe YMMV re some particularly slick materials, a
poorly dressed knot, and VERY high force; but I think that even the
common Fig.8 Bunny Ears will hold with one eye severed. (For the
broken eye strand to pull out, it would have to be pulled back through
the main nip, then around the bottom of the knot, back up through the
nip again, and over the 'biner, which itself has a coefficient of friction
that gives about a 2/3 efficiency!)
I think Luebben was getting mighty theoretical here, so to speak.
Moreover, he continues on the next page to assert that the Bowline
on a Bight is MOREdundant: quite NOT so, and this knot can easily
slip undone, on certain loadings. (Egads, he's got further errors in
knots: the wrong rope end of the EDK is tied off--see my post under
GearHeads re that!)
There are other ways to give two eyes to the Fig.8, as well as to the
Fig.9, for that matter. Voici:
Fig.9 BunnyEars photos
http://www.postimage.org/image.php?v=aV2n19M0]
The topmost knot has black cord marking where Dave Merchant puts
the eyebight in making the knot (which he then decries as not secure
like the Fig.8 verson). The black rope in the lower knot show its
better positioning. (Of course, before falling on this knot, you should
back up those clothespins with some plastic ones!)
And here's the flip side.
http://www.postimage.org/image.php?v=aV2n1Lb9
rev'd Bwl WITH a bight (for separate-eye loading),
& alternative Fig.8 bunny ears
Re that slippage noted above for this Bowline WITH a Bight
(here, in slick new polyester Sta-Set yacht line), it has been
anticipated/DONE by collapsing that eye, and in its place
extending the end-bight as the 2nd eye. This knot appears
to be secure for single-eye loading.
The novel Fig.8 Bunny Ears is pretty secure even w/o the
backflip-locking of the eyebight-end (lowest knot),
but of course that needs to be done. It is a very easy knot
to UNtie after loading. However, the particular dressing given
here--the odd crossing of the parallel strands on the left side
of the knot--, is a bit of a PITA to do, as it torques the eye
bight if done in the usual way (one can arrange to sort of
form it backwards, eye-towards-ends, to ameliorate this).
http://www.postimage.org/image.php?v=Pq2M0G7A
In reply to: If you do a little research you'll find that every time this knot is tested the rope will break outside the knot, never inside.
I've done a little research, and not found this; where ... ?
(And what is it that breaks the rope beyond the knot?!)
In reply to: In Theory a knot will always break within the knot, at the tightest bend.
parts weakened by whatever bending--a tight bend coming
after earlier milder bends will see less force. This is an area
that needs much better, wiser/cleverer testing!
*knudeNoggin*
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acorneau
Mar 3, 2009, 3:33 PM
Post #29 of 43
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^^^ I'm not replying to most of that!?!^^^
knudenoggin wrote: In reply to: If you do a little research you'll find that every time this knot is tested the rope will break outside the knot, never inside. I've done a little research, and not found this; where ... ? (And what is it that breaks the rope beyond the knot?!)
My mistake. I was thinking, "It will break outside of the loops".
You've got a lot of freaky knots there. I would say the standard double-looped figure 8 (super 8, Canadian 8, whatever you want to call it) as well as a Bowline on a bight (the two loop variety) would be more than adequate for any scenario calling for a two-loop knot.
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knudenoggin
Mar 3, 2009, 5:24 PM
Post #30 of 43
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acorneau wrote: You've got a lot of freaky knots there. I would say the standard double-looped figure 8 (super 8, Canadian 8, whatever you want to call it) as well as a Bowline on a bight (the two loop variety) would be more than adequate for any scenario calling for a two-loop knot.
--although any eye failure in practice is likely going to be
from the anchor pulling out and not material breaking,
and so the eye will be intact and able to ultimately hold,
the sliding of material in adjustment might have nasty
consequences! This seems most vulnerable in the case
I showed for the Bowline WITH a bight; it's why I urged
that that knot be used only with eyes clipped as one;
the ENDS now are great to then each go to separate
anchors, for a TR anchor. And this knot will be much
easier to untie, and should be even more quickly tied,
as it is after all just a regualar bowline but tied in the
doubled material; added step of pulling the eyes through
the bight-end for locking off. (It is, yes, at times called
a "Triple (-eye) Bowline" when that end-bight is pulled
out for use qua eye.)
And while the alternative Bunny Ears Fig.8 I show has the
dressing challenges, please note that as a SINGLE-eye knot,
it should be a good candidate to replace the Fig.8,
with its end just looped around and tucked between the
eye legs. --shouldn't jam like the Fig.8 can.
*kN*
(This post was edited by knudenoggin on Mar 3, 2009, 10:38 PM)
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mrswix
Apr 13, 2010, 8:01 PM
Post #31 of 43
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damn you guys got really carried away huh? haha
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socalclimber
Apr 13, 2010, 9:24 PM
Post #32 of 43
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mrswix wrote: damn you guys got really carried away huh? haha
I was thinking the same thing. Jeez, it was a simple question with a simple answer.
The setup is bomber.
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j_ung
Apr 13, 2010, 9:38 PM
Post #33 of 43
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Agreed. There's some truth in the morass that is this thread, though. What is being called bunny ears is not, strictly speaking, redundant. But jeez, it's the rope. If there's no edge-abrasion issue at or above the knot, have at it. If there is an edge abrasion issue -- or if you're just anal retentive (nothing wrong with that) -- a BFK will also work, and it is redundant.
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knudenoggin
Apr 14, 2010, 4:57 AM
Post #34 of 43
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>> I was thinking the same thing ...
Well, gee, think about it for another year and see if it improves.
Better yet, ya might learn the new "Bunny Ears 8" and be free
of jammed knots of that sort.
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USnavy
Apr 14, 2010, 5:04 AM
Post #35 of 43
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Beth Rodden taught me the double figure eight method when I took her multi-pitch trad class. Apparently she uses it exclusively. Enough said.
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majid_sabet
Apr 14, 2010, 6:12 AM
Post #36 of 43
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mrswix wrote: whats up everyone...just a quick question... would a double figure 8 work as a setup for practicing jugging? so basically we would tie the double figure 8, and each "ear" would go to a biner to a bolt in the gym...thanks for any help
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blueeyedclimber
Apr 14, 2010, 3:00 PM
Post #37 of 43
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majid_sabet wrote: mrswix wrote: whats up everyone...just a quick question... would a double figure 8 work as a setup for practicing jugging? so basically we would tie the double figure 8, and each "ear" would go to a biner to a bolt in the gym...thanks for any help [IMG]http://img714.imageshack.us/img714/9370/screenhunter01mar022310.jpg[/IMG]
This is my preferred anchor when I need to haul my pickup truck
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dolphja
Apr 14, 2010, 3:13 PM
Post #38 of 43
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majid_sabet wrote: mrswix wrote: whats up everyone...just a quick question... would a double figure 8 work as a setup for practicing jugging? so basically we would tie the double figure 8, and each "ear" would go to a biner to a bolt in the gym...thanks for any help [IMG]http://img714.imageshack.us/img714/9370/screenhunter01mar022310.jpg[/IMG]
BOMBAR!!!!
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majid_sabet
Apr 14, 2010, 4:07 PM
Post #39 of 43
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blueeyedclimber wrote: majid_sabet wrote: mrswix wrote: whats up everyone...just a quick question... would a double figure 8 work as a setup for practicing jugging? so basically we would tie the double figure 8, and each "ear" would go to a biner to a bolt in the gym...thanks for any help [IMG]http://img714.imageshack.us/img714/9370/screenhunter01mar022310.jpg[/IMG] This is my preferred anchor when I need to haul my pickup truck
so you are tell me that i pass the anchor building 101A course ?
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chadnsc
Apr 14, 2010, 8:29 PM
Post #40 of 43
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majid_sabet wrote: blueeyedclimber wrote: majid_sabet wrote: mrswix wrote: whats up everyone...just a quick question... would a double figure 8 work as a setup for practicing jugging? so basically we would tie the double figure 8, and each "ear" would go to a biner to a bolt in the gym...thanks for any help [IMG]http://img714.imageshack.us/img714/9370/screenhunter01mar022310.jpg[/IMG] This is my preferred anchor when I need to haul my pickup truck so you are tell me that i pass the anchor building 101A course ?
No you pas the posting pictures of anchors 101A course.
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CelticGuy
Jun 21, 2014, 7:06 AM
Post #41 of 43
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dolphja wrote: majid_sabet wrote: mrswix wrote: whats up everyone...just a quick question... would a double figure 8 work as a setup for practicing jugging? so basically we would tie the double figure 8, and each "ear" would go to a biner to a bolt in the gym...thanks for any help [IMG]http://img714.imageshack.us/img714/9370/screenhunter01mar022310.jpg[/IMG] BOMBAR!!!!
Not Bomber. All that has to be done to make this redundant is tie an overhand one each of the bunny-ear bights. Simple fix. OK so it doesn't slip and equalize anymore but you already equalized it first right ?
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sungam
Jun 21, 2014, 2:20 PM
Post #42 of 43
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First off ~nice resurection~ but in reality - how is this not already redundant?
I can't see any one place where a failure would mean a complete failure, or even a shock load.
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CelticGuy
Jun 22, 2014, 6:57 PM
Post #43 of 43
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A double figure-8 basically has 2 bights that are through the end of a figure-8. The 2 bights are a serial single rope and as a result if one gets cut both of them fail. Tie one and pull one of the loops and you'll see what the issue is. This has been documented by Craig Luebben in his anchors and trad climbing books. Bunny Ears are just a glorified American Death Triangle IMO. A death triangle with a cinch that can fail.
Tie an overhand on the bight (on each of those bights - aka bunny ears) and you're bomber. This removes the automatic equalization but why would you want a dynamic equalizing point if you're tied into the anchor with your rope anyway ?
So here's the issue I really see. If for some reason a bight gets chewed up and fails, basically any load will cause the bight to slip through the end of the 8 and hence the second bight will come un-tied. Doing an overhand on each stops this from happening. It's a really simple thing to do and adds extra insurance. Worth it for the extra minute IMO.
I know, you're gonna say, but it's your master rope and it shouldn't fail. I agree BUT a master rope with a tight bend puts way more stress on the rope than a pull in a straight line. Yes, it's unlikely to fail. But why not just be a little bit safer ??? It's costs nothing.
BTW, if you look up carabiner sawing through a rope, you will understand my paranoia. The example was with a carabiner that had been used in a quick-draw and hooked into the hanger. The quickdraw was reversed and the metal chafing on the 'hanger' side was then used by the rope side and it cut through the rope very quickly. If you're pumped or not paying attention you may be using a dodgy 'biner at your anchor!
Yeah, yeah, I'm being very paranoid. maybe a regular bunny-ears has a 1:10,000 chance of failure. Tie overhands and it now has a 1:(10,000)^2 failure or 1:100,000,000. For an extra minute isn't this worth it ?
FYI
http://dmmclimbing.com/...tential-rope-damage/
(This post was edited by CelticGuy on Jun 22, 2014, 7:26 PM)
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