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jberk
Dec 4, 2013, 12:48 AM
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Hello, I am a little confused on when exactly a BHK/BFK should be used. When should I be using the BHK/BFK as opposed to just equalizing from the anchors and using an overhand? Is the BHK/BFK used elsewhere? Sorry I know this is probably a ridiculously basic question but all I can find is a description and what it does not when it should be used. Thanks.
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edge
Dec 4, 2013, 1:03 AM
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jberk wrote: Hello, I am a little confused on when exactly a BHK/BFK should be used. When should I be using the BHK/BFK as opposed to just equalizing from the anchors and using an overhand? Is the BHK/BFK used elsewhere? Sorry I know this is probably a ridiculously basic question but all I can find is a description and what it does not when it should be used. Thanks.
I don't have any clue what those initials stand for.
Big Fu($1ng Knot?
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ncrockclimber
Dec 4, 2013, 1:46 AM
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The Big Fucking Knot (or BFK) can be used when you are creating a master point from two single strands and you want the master point to have redundancy (two loops).
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shockabuku
Dec 12, 2013, 1:14 AM
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jberk wrote: Hello, I am a little confused on when exactly a BHK/BFK should be used. When should I be using the BHK/BFK as opposed to just equalizing from the anchors and using an overhand? Is the BHK/BFK used elsewhere? Sorry I know this is probably a ridiculously basic question but all I can find is a description and what it does not when it should be used. Thanks.
Wow, great, just what I want - to climb with someone who can't even name the knot they don't know when to use.
Fuck.
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ncrockclimber
Dec 12, 2013, 3:12 AM
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Wow, great, just what I want - another internet dickhead who feels the need to make a rude post that adds no value.
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jberk
Dec 12, 2013, 4:15 AM
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Why troll the beginners forums and mock people who are asking anchor safety questions?
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USnavy
Dec 12, 2013, 9:04 AM
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shockabuku wrote: jberk wrote: Hello, I am a little confused on when exactly a BHK/BFK should be used. When should I be using the BHK/BFK as opposed to just equalizing from the anchors and using an overhand? Is the BHK/BFK used elsewhere? Sorry I know this is probably a ridiculously basic question but all I can find is a description and what it does not when it should be used. Thanks. Wow, great, just what I want - to climb with someone who can't even name the knot they don't know when to use. Fuck.
Yea, because you were born knowing what a BFK is, and how to lead 5.12 trad. *roll eyes* Everyone, you included, is ignorant until they learn otherwise.
(This post was edited by USnavy on Dec 12, 2013, 9:07 AM)
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rgold
Dec 12, 2013, 5:33 PM
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I think the your confusion stems from the fact that huge knots like this represent a response to what seems to me to be a poorly-defined and poorly-conceived "need" for redundancy. In short, you never truly need such a knot, which is why it is so confusing figuring out when you do "need" it. Moreover, such knots are big and messy and have various irrelevant loops and so are harder to verify visually.
If some desire for redundancy (of questionable relevance in the real world) requires two loops, you can always tie a pair of figure-eights right next to each other and you'll have better redundancy than the BHK approach.
The problem with an overhand or figure-eight power point is that they are hard to untie if they've been weighted a lot. The bowline on a bight is a better knot and also happens to provide two loops.
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dagibbs
Dec 12, 2013, 10:54 PM
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rgold wrote: The problem with an overhand or figure-eight power point is that they are hard to untie if they've been weighted a lot. The bowline on a bight is a better knot and also happens to provide two loops.
I tend to use an overhand, and deal with the untie problem by leaving a biner through the knot. It gives something to pull on for untying, or wiggling it out of the knot will leave enough slack that the knot undoes more easily.
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shockabuku
Dec 13, 2013, 4:19 AM
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jberk wrote: Why troll the beginners forums and mock people who are asking anchor safety questions?
My charming personality and a response to a question that, I felt, as did Edge apparently, was poorly specified.
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JimTitt
Dec 13, 2013, 5:33 PM
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The lockers are not done up, your going to die anyway so the rest of your worries are merely paranoia.
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MFC
Dec 13, 2013, 7:42 PM
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I was shown the BHK knot when I took an AMGA course years ago.
it is primarily/usually used when constructing a top rope anchor and the master point is some distance from the anchors (think two trees set back from the cliff edge).
A long length of static line is attached to the two trees (or gear/pro) by attaching the ends of the static line to each anchor leaving more than enough slack to hang over the cliff edge.
One then approaches the cliff edge, moves the two lines of static rope to best location over route and then ties the BHK effectively equalizing the two anchors and tying a MP all in one step.
If there is only a small amount of "extra" rope after tying the MP, it can be clipped into the MP. If a lot of extra length is left over it can be wrapped around the static line and tied off to make things neat.
If you use this approach, it tends to minimize the number of times one needs to approach the cliff edge, and in theory minimizes the potential risk at the cliff edge (you could attach a prussic cord to one of the static lines connected to your harness to safeguard against a fall).
This is only one way to set up a top rope anchor. There are other ways equally fast/efficient/safe. Just another tool in your toolbox, if you choose to use it.
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dan2see
Dec 13, 2013, 8:48 PM
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MFC wrote: ... This is only one way to set up a top rope anchor. There are other ways equally fast/efficient/safe. Just another tool in your toolbox, if you choose to use it.
Uhh... that scenario makes sense.
Where I learned to climb, all the cliffs had flat tops with rocks and trees and forest, and we had the same problems.
None of us were leading sport climbs yet, but it was easy to hike up to the top and install the top-rope anchors.
We always had lots of big trees or big rocks to hang from, but they were seldom in a convenient location.
We had to pre-anchor ourselves on the up-hill trees to get to the cliff edge safely, and we also had to extend the Master Point over the edge so it could hang without friction.
So our rules were:
- always two or more anchors, on big trees or rocks
- each anchor totally independent from the others
- the locking biners were independent too, and locked
- use secure knots: fishermans, bowline, 8, or water knot
- extend the MP over the edge
Still, I don't see why you'd add a BFK/BHK in your anchor: I just don't see how it adds any redundancy or strength to the set-up. Just say "no", and simply clip unto the anchor slings.
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knudenoggin
Dec 13, 2013, 8:54 PM
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shockabuku wrote: jberk wrote: Hello, I am a little confused on when exactly a BHK/BFK should be used. ... Wow, great, just what I want - to climb with someone who can't even name the knot they don't know when to use.
?!
Would you say the same thing if 'BF' or 'BH' were replaced with 'ED'?
--seems they named it as well as it's generally named.
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shockabuku
Dec 13, 2013, 10:27 PM
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knudenoggin wrote: shockabuku wrote: jberk wrote: Hello, I am a little confused on when exactly a BHK/BFK should be used. ... Wow, great, just what I want - to climb with someone who can't even name the knot they don't know when to use. ?! Would you say the same thing if 'BF' or 'BH' were replaced with 'ED'? --seems they named it as well as it's generally named.
The name may be appropriate but I don't think it's a de facto standard such as EDK. It may have been an over-reaction - it happens. (shoulder shrug emoticon)
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jberk
Dec 13, 2013, 10:45 PM
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Hey dan2see, so MFC pretty much nailed it. In the top picture you posted the climbing rope passes through the locking carabiners and the anchor rope (picture 2) attaches to a fixed object like a tree. If one rope is used to attached to 2 anchor the rope would create a U bend. If you were to tie this U into a master point (using an overhand) there would only be one loop in the master point. Moreover you would have a hard time adjusting exactly where the master point ends up. My main question is when and where this knot should be used because it seems if the sole perpose is redundancy in the masterpoint it seems to suggest that it is your anchor rope that is at fault for failure. This is the one of the points that confused me the most. After all wile redundancy is important when lead climbing, for the most part, the climber is only tied into one rope (no redundancy). Lastly take a look at rgold posts. He pretty much explained that the BHK/BFK is a "poorly-conceived "need" for redundancy" and "messy and have various irrelevant loops and so are harder to verify visually", which can have potentially devastating consequences. If I made any mistakes or misquoted someone please let me know
Thank you everyone for all your amazing help!
(This post was edited by jberk on Dec 13, 2013, 10:51 PM)
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rgold
Dec 14, 2013, 4:58 PM
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MFC wrote: I was shown the BHK knot when I took an AMGA course years ago... ...A long length of static line is attached to the two trees (or gear/pro) by attaching the ends of the static line to each anchor leaving more than enough slack to hang over the cliff edge. One then approaches the cliff edge, moves the two lines of static rope to best location over route and then ties the BHK effectively equalizing the two anchors and tying a MP all in one step...
A few comments.
1. This method isn't optimal and isn't the one many AMGA people use. The usual sequence is to secure the rope to one remote anchor, approach the edge and position the power point knot, and then secure the rope to the second anchor with a clove hitch, allowing for very fine adjustment of the arm length. (The clove hitch can be backed up if desired.) This is much better for several reasons, among them
a. Getting the power point knot position right by tying into both remote anchors is much harder since one isn't near the cliff edge to judge positioning accurately.
b. Getting appropriate load distribution is much harder if the length of the two arms has to be determined by the position of the BHK, which is extremely hard to position accurately, is hard to adjust finely once tied, and which, because of all the turns of rope in it, will eject slack in especially unpredictable ways when loaded.
2. Whichever method is used, the BHK is not an essential part of it. The main argument for the BHK seems to be that it provides the redundancy of two power point loops. Presumably, the concern is that a single loop could abrade against the rock surface and be cut. This makes no sense to me. If there is enough abrasion to cut through a strand, it is even more iikely to do the same thing to the knot itself, in which case two strands of the power point will be of no use.
Moreover, one usually sets up the anchor so that the power point knot is dangling over the edge and abrasion is an extremely remote possibility. A rubbing power point is indication of an incorrectly positioned power point, and should be dealt with by adjusting the anchor arm length, not by accepting a bad situation and doubling up the power point loops.
3. If serious power-point rubbing seems inevitable, the solution is not to stick one's head in the sand and tie a BHK. Rather, one ought to conclude the route cannot be safely rigged and either move on to something safer or else (oh the horror) place the belayer at the top of the cliff.
4. As is typical in many "safety" discussions, folks invest time worrying about the wrong things. In all the most common situations, it isn't abrasion on the power point loops that is cause for concern, it is abrasion on the anchor strands running from the remote anchor and going over the edge. If the edge is at all pronounced, some kind of padding is called for. If the nature of the route being top-roped is that the anchor will be loaded with a sideways component, then directionals to prevent the anchor arms from sawing sideways over the edge are called for.
Even better when there will be rope motions is to to construct a gear anchor over the lip, on the face, and rig the power point to that, with the cliff-top anchors serving to back up the gear anchor and so not being loaded at all.
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shockabuku
Dec 14, 2013, 7:28 PM
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rgold wrote: MFC wrote: I was shown the BHK knot when I took an AMGA course years ago... ...A long length of static line is attached to the two trees (or gear/pro) by attaching the ends of the static line to each anchor leaving more than enough slack to hang over the cliff edge. One then approaches the cliff edge, moves the two lines of static rope to best location over route and then ties the BHK effectively equalizing the two anchors and tying a MP all in one step... A few comments. 1. This method isn't optimal and isn't the one many AMGA people use. The usual sequence is to secure the rope to one remote anchor, approach the edge and position the power point knot, and then secure the rope to the second anchor with a clove hitch, allowing for very fine adjustment of the arm length. (The clove hitch can be backed up if desired.) This is much better for several reasons, among them a. Getting the power point knot position right by tying into both remote anchors is much harder since one isn't near the cliff edge to judge positioning accurately. b. Getting appropriate load distribution is much harder if the length of the two arms has to be determined by the position of the BHK, which is extremely hard to position accurately, is hard to adjust finely once tied, and which, because of all the turns of rope in it, will eject slack in especially unpredictable ways when loaded. 2. Whichever method is used, the BHK is not an essential part of it. The main argument for the BHK seems to be that it provides the redundancy of two power point loops. Presumably, the concern is that a single loop could abrade against the rock surface and be cut. This makes no sense to me. If there is enough abrasion to cut through a strand, it is even more iikely to do the same thing to the knot itself, in which case two strands of the power point will be of no use. Moreover, one usually sets up the anchor so that the power point knot is dangling over the edge and abrasion is an extremely remote possibility. A rubbing power point is indication of an incorrectly positioned power point, and should be dealt with by adjusting the anchor arm length, not by accepting a bad situation and doubling up the power point loops. 3. If serious power-point rubbing seems inevitable, the solution is not to stick one's head in the sand and tie a BHK. Rather, one ought to conclude the route cannot be safely rigged and either move on to something safer or else (oh the horror) place the belayer at the top of the cliff. 4. As is typical in many "safety" discussions, folks invest time worrying about the wrong things. In all the most common situations, it isn't abrasion on the power point loops that is cause for concern, it is abrasion on the anchor strands running from the remote anchor and going over the edge. If the edge is at all pronounced, some kind of padding is called for. If the nature of the route being top-roped is that the anchor will be loaded with a sideways component, then directionals to prevent the anchor arms from sawing sideways over the edge are called for. Even better when there will be rope motions is to to construct a gear anchor over the lip, on the face, and rig the power point to that, with the cliff-top anchors serving to back up the gear anchor and so not being loaded at all.
It seems to me that the usefulness of this knot - if it has any - is that you CAN tie off both anchor points and move to the powerpoint location and then tie that. I don't know why that would be significantly desirable but for anchors that are far from the powerpoint I could see where it might save some time and/or effort.
I don't see much usefulness from the double loop out the bottom and the extra loop out the top; I think they're just an artifact of tying an overhand on two bights where the undesired rope length is put into the loop out the top. I think the Big part of this thing is a relatively undesirable consequence of the order in which the whole thing is constructed.
When would I use it? Maybe when my anchors were pretty far back from the edge and when I couldn't see where the powerpoint is hanging (can't tell how well equalized my two anchors are. However, I think it would be a pain in the ass to tie it at that point since I'd probably be rapping on one of the two anchor lines.
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