Bowline for Master Point Knot?
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Abram Herman wrote: I'm really confused by this statement. How does better rope management affect how many things are getting clipped to the master point? I generally belay direct off the anchor using an atc in autoblock mode on the master point, and then I tie myself in with the rope using a locker on the shelf to keep the atc clear from obstructions so it can function properly. Why is this bad, and how could it be avoided through different/better techniques?for 2 bolts youre absolutely and utterly fine for a multipoint trad anchor with widely spaced nuts, ie a WIDE angle between the anchor arms ... there may be some concern that in a VERY high factor fall youll get pulled up and place a sideways pull on some of the outer arms, thus lifting out the nuts ... generally cams are less susceptible to this ... and honestly if you were lifted up that much on a fall, even with a regular anchor unless you had an upward pull piece, youd have the same problem some mutter about triaxial loading on the shelf biner ... but honestly for most applications and unless you have WIDE arms on the anchor its not a worry IMO as long as you keep a biner in the masterpoint, the knot itself wont fail, and even then there is some testing to suggest that biner in masterpoint stuff is just a myth anyways on nylon cord guides use and teach the shelf all the time ... ;) |
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those bolts look sketch |
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That's true bearbreeder, but since I'm only using it when bringing up the second, that scenario couldn't happen. I'd be in on the master point if I was belaying a leader :-) |
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Abram Herman wrote:That's true bearbreeder, but since I'm only using it when bringing up the second, that scenario couldn't happen. I'd be in on the master point if I was belaying a leader :-) I guess I could see the triaxial loading argument, but as you said, you'd have to have some way-too-wide angles in your anchor, and even if you did the triaxial loading weakness would be inconsequential for that application.then yr totally and utterly fine ... you wont die from it, except from the intrawebs =P Jake Jones wrote: When I use the "shelf" I always clip one leg from each piece. Does anyone else do that? I thought that's the way it's supposed to be done for purposes of redundancy.thats the way you should do it ... and how they teach ya the shelf is a useful tool ... some people prefer to tie a larger masterpoint, others use a big masterpoint biner, and some use the shelf instead ... there is no "right" way ... unless its MY way in an intraweb argument of course ;) |
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Jake, if the follower is being belayed directly off the master point, it couldn't happen... How would they lift the anchor UP? |
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Well, I don't know if nuclear winter is covered in UIAA standards. Does anybody know of any research on the subject? I do try to be a safe climber... |
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I've been using the alpine cockring for a while now for trad. So far I'm loving the ease of the system and how quick it is. |
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rgold wrote: The reason no one has mentioned it is because it isn't true. The two knots use about the same material; actually, slightly less for the bowline on a bight since it is based on an overhand rather than a figure eight.Not quite. I just set up a standard 3-point anchor with my cordelette. The "height of the knot" is the length of the center leg to the top of the knot: Overhand: 1. Height of knot:14" 2. Bottom of master point: 22" 3. Master point loop: 6" Figure 8: 1. Height of knot: 14" 2. Bottom of master point: 19" 3. Master point loop: 2" BOAB: 1. Height of knot 11" 2. Bottom of master point: 16" 3. Master point loop: 2" I couldn't tie the BOAB at the same height as the other knots because there was not enough material. This clearly shows that the BOAB in this configuration takes much more material than the other knots. |
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Abram Herman wrote: I'm really confused by this statement. How does better rope management affect how many things are getting clipped to the master point? I generally belay direct off the anchor using an atc in autoblock mode on the master point, and then I tie myself in with the rope using a locker on the shelf to keep the atc clear from obstructions so it can function properly. Why is this bad, and how could it be avoided through different/better techniques?Oh for god's sake. I never said the shelf was bad. I never said it had to be avoided, except perhaps if you are going to use a bowline on a bight instead of the usual figure-eight. There are numerous ways to arrange everything at the power point without resorting to the shelf and without anything malfunctioning, that's what I meant by "intelligent rope management." I never said these ways were better or worse than using the shelf, just that they were available if you don't want to use the shelf. |
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I just spent two weeks climbing multipitch trad routes, up to 15 pitches long, and I don't own a cordelette. Just sayin... |
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Agreed Ryan, cordelettes have been massively oversold. But they do have their occasional uses, and that's what we're talking about. |
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"Allen, I don't know how you got your numbers. Perhaps you aren't tying a bowline on a bight, which, sadly, is not the same as a bowline tied with a bight of rope?" |
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Rebuilt my experiment and took pictures, so here we go... |
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Look man. You can do this. But what's the logic behind it? Your adding an extra step to an overhand. If your logic is it's easier to untie, u've already fkd ur anchor up in the 1st place. You shouldn't have enough force generated on a TR anchor to make it overly difficult/impossible to untie a figure 8 on a boatload of cord. |
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Allen Corneau wrote: That 6" loop gets folded in half and then some gets taken up in the knot.Ah yes, right you are. I was overly focused on the concept of the knot using "more material." I still wouldn't think of this as some massive deal-breaking difference though; about 3" in arm length for 7mm cord and less for 6mm cord. Ryan Kampf wrote: But what's the logic behind it?No reason to use it in general. If the rigging is going to take a lot of continual loading, eg if one was going to be hanging on it for a long time while equipping a route, then the welding of the figure-eight is more of a problem and the bowline on a bight is the logical choice. Ryan Kampf wrote: Better yet, ditch the cord, use a 48" runner and the sliding x method.Well, yer not gonna die, but the sliding-X has been tested rather extensively at this point and it doesn't do a better job at equalizing while introducing the potential of anchor extension. And if the anchor in question is a three-point anchor, there is no sliding system that is any good at all. So if logic is still a valid criterion, then no, the sliding-x method is not "better yet." Ryan Kampf wrote:Let me put this in simple terms. If you set up your dynamically equized [sic] anchor properly (which is Increadably [sic] easy), no one single piece is going to let go (as long as the placement isn't completely worthless). The whole system while fail simotaniously. [sic]This is just not true. And I'm not speaking hypothetically here. I know very experienced climbers with multiple big-wall ascents in remote locales in their resumes who have experienced the failure of one of several anchor points. Of course, one can always simply define these anchors as "completely worthless," but then you are just ignoring the problem, not solving it. Such failures are certainly very rare, but they do happen, and the entire point of most rigging techniques is to guard against such unlikely but dangerous outcomes. |
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Ryan Kempf wrote:Long story short but long winded.Then it wasn't a long story short. Just a long story. That's about the nicest thing I can say about your post. Thanks to everyone else who has contributed meaningful discourse to the thread. |
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9 out of ten times all of this stuff... |
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For two-bolt belays I use an 8mm 120cm sling to form the powerpoint. This can be difficult to untie if the second has fallen off a lot and is on the heavy side. Hence I now tie an alpine butterfly rather than an overhand/fig8. |
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Seems like a decent idea to me. The only questions/dislikes I had we're these: |
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bearbreeder wrote: just use a fig 9 ... easy to tie and untie .... ;)+1 |