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altelis
May 14, 2007, 7:01 PM
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I am looking for data/research/examples of whether this is a safe method for tying in. pretty straight forward. thats it. any other questions should be cleared up in the disclaimer section---
DISCLAIMERS:
A) I've already done a forum search, thanks. nothing reveals research, just people pontificating, making deductions, and telling useless ramblings about how they haven't died yet
B) related to A), i'm looking for fact/research not people's opinions---that is why this is posted here and not anywhere else. again, either research or specific examples of either knot going wrong where PILOT ERROR is not to blame. ie, the knot tied and used correctly was the problem.
C) I'm aware the figure 8 is easier to inspect, we don't need to beat this point to death
D) I'm not looking for "is this knot better than the rethreaded figure 8"- i'm looking for "is this knot an equally safe alternative to the rethreaded figure 8"
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nthusiastj
May 14, 2007, 7:28 PM
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My partner and I both use it.
I've died like 300 times beacuse it's TOTALLY unsafe.
It's really hard to inspect if you never learn to tie it. I can glance at one and tell if it's tied right.
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tradmanclimbs
May 14, 2007, 7:41 PM
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Fact. doubble bowline may loosen when unweighted.
Fact.Figure eight will not losen when unweighted.
Fact, Doubble bowline falls apart if not completly tied.
Fact. A half tied figure eight is still strog enough to hold a climber.
Fact. several serious injurys documented with improperly tied or loosened bowlines. There was even a nasty one on the BD website last year.
Fact. never heard of a properly tyed fig 8 untying and dropping a climber.
Fact, bowline unties easier than a figure eight.
Fact. Even with skiny ice floss the figuer eight unties ok even after the huge whip.
Fact. You can't start this topic without haveing to read peoples opinions
Even a single bowline is bomber strong when under tension. Problem is that when unweighted, bowlines tend to loosen up and kill or maim you or just help you crap your pants The only real reason to use the doubble bowline INMOP is so you can look cool with an old school knot
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altelis
May 14, 2007, 7:54 PM
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thanks, but none of these help. i know the knot is strong enough, i already said i don't need anyone mentioning the db is harder to inspect (i made that point for you)
what i am looking for is hard evidence that the bowline has a HIGH LIKELIHOOD of coming untied when used as a tie in knot. thanks
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altelis
May 14, 2007, 8:03 PM
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or, indeed, hard evidence that is does not. i want more than the fire side discussions to which i have already been privy....:)
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tradmanclimbs
May 14, 2007, 8:07 PM
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Hard evidence is that I personaly have seen it happen several times to partners and I hardly ever climb with anyone who uses the knott. Out of like the 10 times i have climbed with a parter who uses that knott in the 24yrs I been climbing I have twice said. dude, your knotts loose and it was. The coutless times that I have told a climber to check their figure 8 it was either just their back up knott or if the actual figure eight was loose it still would not have possibly actually untied. Pretty cool test. Tie only hALF of a figure eight and then bouce test it. You will be fine. it's bomber. look On the BD website and see if they still have the photos of the guy full of rods and screw after his doubble bowline came untied. That was pleanty fact for me
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misanthropic_nihilist
May 14, 2007, 8:09 PM
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I think you'll have a very hard time finding evidence that the double bowline comes untied. Because it doesn't, when tied properly.
I couldn't find any papers on the slippage of the bowline, but it's generally accepted that the bowline slips under repetitive loading. The figure-8 slips to a degree, until it cinches down, then doesn't slip anymore.
Black Diamond's QA engineer did a quick study on his old rope to find it's strength after having caught many whippers:
http://www.bdel.com/scene/beta/qc_kp_archive.php#011907
The low strength of the rope could be seen as hard evidence that the figure-8 is preferred to the bowline due to it's higher strength.
As long as the bowline is tied properly, and with a back-up knot it is perfectly safe. It sounds like you're looking for evidence that bowlines magicly untie themselves.
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tradmanclimbs
May 14, 2007, 8:11 PM
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They do.
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overlord
May 14, 2007, 8:17 PM
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tradmanclimbs wrote: Fact. doubble bowline may loosen when unweighted. Fact.Figure eight will not losen when unweighted. Fact, Doubble bowline falls apart if not completly tied. Fact. A half tied figure eight is still strog enough to hold a climber. Fact. several serious injurys documented with improperly tied or loosened bowlines. There was even a nasty one on the BD website last year. Fact. never heard of a properly tyed fig 8 untying and dropping a climber. Fact, bowline unties easier than a figure eight. Fact. Even with skiny ice floss the figuer eight unties ok even after the huge whip. Fact. You can't start this topic without haveing to read peoples opinions Even a single bowline is bomber strong when under tension. Problem is that when unweighted, bowlines tend to loosen up and kill or maim you or just help you crap your pants The only real reason to use the doubble bowline INMOP is so you can look cool with an old school knot
a) thats why you tie a safety knot with the tail.
b) just what you mean by half-tied?? there was an accident a whle ago when someone was dropped in a gym because he presumably bungled the fig8 tiein. got to the top of the route, leand back and decked.
c) i also never heard of a properly tied bowline dropping a climber. if it loosened up enough, it obviously wasnt properly tied. the same goes for fig8 offcourse.
d) i use the bowline exactly because its easier to untie. if i take a whipper on a hard route, i prefer a knot that i can untie easily while pumped. yes, you can also untie the fig8 but it takes more effort.
like always, you have to KNOW the knot before using it, and the only REAL drawback i see in a bowline vs fig8 (apart from it weakening the rope a bit more) is that its not easy to visually check. i also usually manage to make a smaller knot with a bowline than with fig8 and that comes handy somethimes.
in short, if you really know how to tie and inspect a bowline, go ahead and use it. i still use fig8 on most climbs because i can tie it quicker and its easier to inspect, but if i expect to fall, i use a (double) bowline.
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Dillbag
May 14, 2007, 8:31 PM
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In reply to: if i expect to fall, i use a (double) bowline
Which is what I used to do, but really if you tie-in with an expectation of falling... Well you'll probably fall...
I only tie-in with the double-bowline... And no, it doesn't get loose. I tie it properly, snug and close to the loops on my harness. And follow up with a back-up knot.
Multi-pitch all day trad routes swinging leads... Still as tight on top as on the bottom.
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tradmanclimbs
May 14, 2007, 8:32 PM
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By half tied that is exactly what I mean. Tie half of a figure eight and bounce test it , you will see. If it failed it must not have even remotely resembled a figure eight. Properly inspected and cinched up tight with a back up knott a bowline is fine for sport climbing. Even though several sport climbing accidents with this knott.... I just don't trust the knott to not untie even with a back up over the course of a long day of multi pitch where you have many other duties other than re checking your tie in knott. Personaly INMOP when the figuer eight works so well it is just not worth the risk of useing a knott that I have personaly wittnessed unties itself. I do use the Bowline to lower after threading anchors. I trust it when its under load. I do not trust it when it is unloaded repetedly over the course of a day. Again TJMOP Fact> You can't talk about this subject without dealing with opinions It's just like abortion, polotics and gun control.
(This post was edited by tradmanclimbs on May 14, 2007, 8:36 PM)
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majid_sabet
May 14, 2007, 8:34 PM
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tradmanclimbs wrote: Fact. doubble bowline may loosen when unweighted. Fact.Figure eight will not losen when unweighted. Fact, Doubble bowline falls apart if not completly tied. Fact. A half tied figure eight is still strog enough to hold a climber. Fact. several serious injurys documented with improperly tied or loosened bowlines. There was even a nasty one on the BD website last year. Fact. never heard of a properly tyed fig 8 untying and dropping a climber. Fact, bowline unties easier than a figure eight. Fact. Even with skiny ice floss the figuer eight unties ok even after the huge whip. Fact. You can't start this topic without haveing to read peoples opinions Even a single bowline is bomber strong when under tension. Problem is that when unweighted, bowlines tend to loosen up and kill or maim you or just help you crap your pants The only real reason to use the doubble bowline INMOP is so you can look cool with an old school knot
I just want to say that rescue community uses bowline very often during rigging to rescue climbing noobs, so get your facts cleaned up .
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tradmanclimbs
May 14, 2007, 8:39 PM
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fact. When rigging, the bowline is under load. Fact. I use the Bowline when rigging myself. Fact, just cause it says suuurch an rescue on the truck don't mean they the know shit from shinola Some SAR are top knotch and some are down right scary!!!
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rgold
May 14, 2007, 8:42 PM
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Atelis, the problem with your question is that you don't make it clear what "safe method" means, and most of the arguing and pontificating could be construed as contention about precisely that definition.
If "safe method" only means knot strength, then there is no question that the bowline is strong enough, and you don't need a double bowline either.
There has been general agreement for years that the "correct" bowline for climbing is one (single bowline is fine) with the so-called Yosemite finish and a double-overhand backup knot. This is what should be tested then, and the tests need to be done with dynamic climbing rope.
The question, given that strength is not a concern, is what should be tested.
The complaints one generally hears about the bowline are:
1. It is harder to verify that a bowline is correctly tied than it is to verify that a figure 8 is correctly tied.
2. The bowline is more susceptible to coming loose than the figure 8.
3. The bowline can come undone if the loop is loaded in a pair of opposite directions off the axis defined by the standing part of the rope (for instance if you clipped a sling from an anchor to the loop.)
Item 1 belongs to the realm of Social Science and seems to me to be pretty hard to verify in an objective way. It isn't even clear that there is an incorrect way to tie a bowline that doesn't fall apart in your hands immediately. I suspect this is primarily an issue for gyms in which it is hoped that employees can spot incorrectly tied knots.
Item 2 might be tested with a device that shakes and/or cyclically loads the knot. I don't know of such tests.
Item 3 has been tested by the German Alpine Club with, I have been told, negative results. But my understanding is that they did not test the "correct" bowline described above, and it is clear that the Yosemite finish/stopper knot combination would make a difference in whether or not the bitter end pulls through.
On the basis of these tests, the DAV concluded the figure 8, was "safer" than a knot that might have been the "wrong" bowline. Moreover, the loading configuration of item 3 is one that is now known to cause the figure 8 to roll, suggesting that neither knot should be used (or tested) without a stopper knot.
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majid_sabet
May 14, 2007, 8:43 PM
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tradmanclimbs wrote: fact. When rigging, the bowline is under load. Fact. I use the Bowline when rigging myself. Fact, just cause it says suuurch an rescue on the truck don't mean they the know shit from shinola Some SAR are top knotch and some are down right scary!!!
============ READ test 2 & 3 ===========
http://www.xmission.com/...pull_tests_7-00.html
At the MRA Intermountain Recert in July we did a pull-test session using a vehicle winch and our group's load cell. The usual disclaimers apply here - these are all quick look tests, a single pull on each setup, and there's no control over the rate of pull.
A quick word on safety - since the picture looks a bit sketchy. Everybody in the photo is 10-15 feet back from the winch cable and the sample - something you can't really see from this angle. The whole system is steel except for about two feet of Nylon static rope. That means the energy storage in the system is very small. (If you do this with dynamic rope, be careful -things fly around more.) The forces we were generating were well under the strength of the cable and shackles we used to connect to the sample. A blanket was placed on the line at the sample to minimize the recoil. (In most of the pulls, we had one on each side of the sample.) The people closest to the sample were all wearing safety glasses or plastic sunglasses. When the sample failed - in every case things traveled down and close to the line of pull. The best way to do this kind of testing is to make a lexan shield to put over the sample. That way everyone can see through it, but breaking parts are contained.
Results
Test #1: Pull a Gibbs (dimpled, "rescue" verson) on used 11 mm static rope.
Result: Stripped the sheath off the rope at 2560 lb. Inside the core of the rope was a tracer that said "New England Rope, 1997, 11mm"
Test #2: Test 5.5 mm Vectran. The load was applied to a loop tied with a triple fisherman's knot.
Result: Cord broke at TFK at 3580 lb.
Test #3: Test 5.5 mm Vectran. The load was applied to a single strand with a bowline in one end and a figure-eight on a bight at the other end.
Result: Cord broke at figure-eight knot (!!!) at 1200 lb.
Test #4: Pull an old, used 8mm prusik to failure. The material was 8mm nylon cord, tied with a double fisherman's knot and wrapped as a 3-wrap prusik on used 11 mm New England static rope, tied with a figure eight on a bight at the end. The load was placed between the prusik and the 11 mm rope.
Result: Cord broke where it enters the prusik hitch at 1870 lb.
Note: This is very low for 8mm material.
Test #5: Test 5mm Technora (orange sheath). The load was applied to a loop tied with a double fisherman's knot.
Result: Sheath broke at 2340 lb. Core untied by pulling through knot.
Note: The breaking strength is very low for Technora (Tech Cord). I have no way to confirm that the material was actually Technora.
Test #6: Pull an old, used piece of 7/16" goldline rope. The load was applied to a single strand with figure-eight knots at each end.
Result: Broke at knot at 3090 lb.
Test #7: Test 5mm Technora (orange sheath). The load was applied to a loop tied with triple fisherman's knots.
Result: Cord broke at shackle at 3720 lb.
Test #8: Pull a 10 year-old homemade 1" sling to failure. 5 bar tacks. Load was applied to the loop.
Result: Broke at shackle at 4240 lb.
Test #9: Pull a 5/8" sewn runner with 6 bar tacks. Load was applied to the loop. Unknown manufacturer.
Result: Broke at shackle at 5050 lb.
Test #10: Test old, used 5.5mm Vectran. The load was applied to a loop tied with a triple fisherman's knot.
Result: Cord broke at shackle at 2520 lb
Test #11: Test the beer knot. This is an alternative to the water-knot. It's tied as an overhand follow-though, but open up the tubular webbing and do the follow through inside the other piece. The load was applied to a loop of used 1" webbing tied with the beer knot.
Result: Webbing broke at shackle at 4750 lb.
Test #12: Test the holding power of a belayer using a Munter hitch. The Munter hitch was tied with used 11mm static rope on an aluminum carabiner. The belayer did not wear gloves, but he sat down, braced himself and held on for all he was worth.
Result: Slipped at 1430 lb
Note: this doesn't represent a typical belay.
Test #13: Same test of a Munter hitch under more normal belay conditions. Belayer standing, wearing gloves.
Result: Slipped at 670 lb
Note: Without measuring the force applied by the belayer, this is a very subjective test. In drop tests conducted by others on a Munter hitch belay with a 200 kg load, factor 1/3 drop on static rope, the belayer has always been unable to keep the load from hitting the ground.
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tradmanclimbs
May 14, 2007, 9:43 PM
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majid, What exactly does any of that have to do with which knott is used for tie in?? Does kind of prove that some suuuurch an rescue do some pretty weird shit like testing dynamic belays with static rope Rgold. don't you find it interesting how many catastrophic failures with grave injury are documented with the bowline as a tie in VS the figure eight considering that the vast majority of climbers tie in with a figure eight? There is your social studies test for you. Find the number of reported accidents due to tie in failure. break it down into bowline vs figure eight. Do a survey to establish what we allready know which is that 99% of climbers use the figure eight to tie in with . Then work your model on which knott is more likly to be involved in a catastrophic failure in real world climbing use.
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altelis
May 14, 2007, 9:52 PM
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not to be a dick tradmanclimbs, but did you know that 68.57% of statistics are made up right on the spot. this is the lab. PLEASE back up what you are saying with data. if you do a poll on this site with a considerable number of replies that says that 99% of climbers tie in with a bowline, fine. if you have a previously published report that says so, fine (considering sources check out). but hell, i say 67% of climbers tie in with the bdl bowline.
now what? we just argue all day long over which is right.
and just sheer proportionality of accidents doesn't help---i need this weighted with whether the klnot was double checked or not, etc.
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gunkiemike
May 14, 2007, 10:25 PM
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Altelis, this is an interesting thread. But what are you going to do in the likely event that no one comes up with rigorous test data to address your question? Probably the same as we all have done - pick the knot you prefer. And then go out and climb something.
You want (challenge?) someone to prove it's not safe. Well, there is an old saying about proving a negative...
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tradmanclimbs
May 14, 2007, 10:25 PM
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Alte. I suggested that you do a poll and I believe that your poll will show that well over 90% of climbers in the USA use the figure eight for tieing into the rope. Conducting that poll in this thread only shows you what precentage of users on in this thread use whatever knott. That possibly could be weighted on the bowline side as they are a minority and may be more inclined to click on the subject vs someone who is useing the figure eight and could care less what others do with a bowline. I believe that if you run the numbers on precentage useing which not and number of accidents with each knott you will come up with a real life stat that will be quite usefull. It is not nessicary to know if the knott was dressed properly. The results of these numbers will show which knot is most likly to fail in real life application where the knott may or may not be properly tied. The fact that the knott was improperly tied caused the failure is part of the real life application of said knott. You can't replicate a bunch of kids, stoners, drunks, old hippies, nerds, techies, granoloa heads,Caffine and nicotine addics, gung ho army rangers, frat boys, wall rats and trustafarians hanging out at the crag or liveing on a wall in the lab. My idea is to assume that the entire spectrum of users is included in the survey and then see what the results of this diverse user group actually useing either tie in method have produced.
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icedpulleys
May 14, 2007, 10:29 PM
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majid_sabet wrote: Test #3: Test 5.5 mm Vectran. The load was applied to a single strand with a bowline in one end and a figure-eight on a bight at the other end. Result: Cord broke at figure-eight knot (!!!) at 1200 lb.
LOL
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altelis
May 14, 2007, 10:32 PM
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tradmanclimbs wrote: You can't replicate a bunch of kids, stoners, drunks, old hippies, nerds, techies, granoloa heads,Caffine and nicotine addics, gung ho army rangers, frat boys, wall rats and trustafarians hanging out at the crag or liveing on a wall in the lab. My idea is to assume that the entire spectrum of users is included in the survey and then see what the results of this diverse user group actually useing either tie in method have produced.
this is true. however, this whole debate got started because one of my partners wigged out on me and told i would die because i use the dbl bowline instead of a fig 8 follow through. i ended the conversation by telling her i would, for her benefit, use the 8 WITH HER until i could convince her otherwise (besides the "i've never had a prob with it and have climbed over a few hundred pitches with it on hard sport and trad, multi and single pitch")
so, while i'm not assuming i'm perfect, i do know that i don't climb drunk or stoned, nor an army ranger, etc.
and i'm not trying to prove a negative---i'm trying to actually prove the positive, i was just trying to avoid giving a slant to this discussion right off the bat (too late...)
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tradmanclimbs
May 14, 2007, 10:34 PM
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If you have 10 people useing knott A with 2 failures and 100 people useing knott B with 4 failures, Knott A is 20% likly to fail in use while Knott B is 4% likly to fail in real use. What actually caused that failure is is not important. The end result is what is important. it's a yes or no question. live or die simple as that
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icedpulleys
May 14, 2007, 10:40 PM
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1. I distinctly remember an accident report in Rock and Ice discussing a knot untying while on lead. My memory is fuzzy, but I believe that it was a double bowline that was not backed up (or was backed up without sufficient tail). This would have been several years ago. If I remember correctly, the climber (I think woman) was able to clip her belay loop into a draw on a overhanging route and wait for a rope to be brought up to her.
It's possible that the accident report referenced here
http://www.utahclimbers.com/phpBB2/viewtopic.php?=&p=12373
is what I'm thinking of. I was unable to find the report by googling.
2. If you want hard data, contact rope manufacturers. Or, get in touch with a mechanical engineer and run your own.
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desertdude420
May 14, 2007, 10:44 PM
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I agree with tradman on this one. Search and rescue/firefighters use some pretty crazy methods. My friend/climbing partner joined the fire dept. and started training. He would tell me horror stories of the guys using way scetchy knots, static ropes, and rappel techniques. So using them as an example of what you're supposed to do is probably not a good idea.
That said, why not use a double figure 8? Why use ANY knot that is not the accepted standard? Too cool to tie in like the rest of us?
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