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knotting slings with overhand knot(s)
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sverris


Aug 12, 2012, 3:45 PM
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knotting slings with overhand knot(s)
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We all know the overhand knot will do the job when joining ropes for rappelling (another debate). It seems like this should also be a perfectly good knot for tying the sling that you would rap from.

Why not the DFK you may ask?

Winter, wind, dark, gloves etc are all good reasons for tying a more simple knot. Will two overhand knots (rolling issue) do the trick or will this be the end of me?


moose_droppings


Aug 12, 2012, 6:00 PM
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Re: [sverris] knotting slings with overhand knot(s) [In reply to]
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sverris wrote:
We all know the overhand knot will do the job when joining ropes for rappelling (another debate). It seems like this should also be a perfectly good knot for tying the sling that you would rap from.

Why not the DFK you may ask?

Winter, wind, dark, gloves etc are all good reasons for tying a more simple knot. Will two overhand knots (rolling issue) do the trick or will this be the end of me?

Whats a DFK? You mean an EDK?

What kind of load do you plan on putting on this knot?

I don't see any reason for not using a water knot for joining webbing together. I'd say your reasons are good ones for not using an EDK in webbing when things are less then optimal.

Your also comparing apples (rope) to oranges (webbing).


socalclimber


Aug 12, 2012, 8:25 PM
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Re: [moose_droppings] knotting slings with overhand knot(s) [In reply to]
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Good points from Moose. Just remember, what ever you do, both of those style knots must be checked BEFORE you rely on them.


marc801


Aug 12, 2012, 11:41 PM
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Re: [moose_droppings] knotting slings with overhand knot(s) [In reply to]
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moose_droppings wrote:
sverris wrote:
We all know the overhand knot will do the job when joining ropes for rappelling (another debate). It seems like this should also be a perfectly good knot for tying the sling that you would rap from.

Why not the DFK you may ask?

Winter, wind, dark, gloves etc are all good reasons for tying a more simple knot. Will two overhand knots (rolling issue) do the trick or will this be the end of me?

Whats a DFK? You mean an EDK?
Maybe he meant double fisherman's knot? Which is totally the wrong knot for webbing, btw. An EDK *is* an overhand knot.


sverris


Aug 13, 2012, 3:35 AM
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Re: [sverris] knotting slings with overhand knot(s) [In reply to]
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I guess I was a bit unclear in my first post. My question concerns tying cord together, like when using your cordelette or spare prussik to sling a hole in the rock, pinched boulder etc.

And yes, i did mean the double fishermans knot.


Guran


Aug 13, 2012, 4:37 AM
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Re: [sverris] knotting slings with overhand knot(s) [In reply to]
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Ok, an honest answer for which i take no responsibility, or claim to have no evidence:

An overhand (EDK) will be safe for your abseil, as will a double fisherman.
However, the DFK might stay safe longer. Somthing the next climber will be grateful for.


njrox


Aug 13, 2012, 6:11 AM
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Re: [sverris] knotting slings with overhand knot(s) [In reply to]
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sverris wrote:
My question concerns tying cord together, like when using your cordelette or spare prussik to sling a hole in the rock, pinched boulder etc.

I would use a double fisherman's knot for cord and a water knot for webbing in this situation.

The EDK (and I personally use two knots and a full arm's length of tails) holds a rappel with static forces. As far as taking a fall, no idea.


rocknice2


Aug 13, 2012, 6:22 AM
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Re: [sverris] knotting slings with overhand knot(s) [In reply to]
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I use the EDK for ice climbing and mostly use the DFK for rock but in a jam, if its dark and cold, I'd probably use the EDK.


(This post was edited by rocknice2 on Aug 13, 2012, 6:23 AM)


wivanoff


Aug 13, 2012, 9:16 AM
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Re: [sverris] knotting slings with overhand knot(s) [In reply to]
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In reply to:
Winter, wind, dark, gloves etc are all good reasons for tying a more simple knot. Will two overhand knots (rolling issue) do the trick or will this be the end of me?

The DFK used to be used to make "permanent" runners out of webbing BITD. See the 1972 Chouinard catalog page 14. There's nothing wrong with using a DFK in webbing except it uses up a lot of material and is difficult to untie.

While most people use a Ring Bend (Water Knot) in webbing, I don't see any reason why an EDK in webbing wouldn't be ok for a rap anchor in the circumstances you describe. I'd use it. I think it's been discussed on Canyoneering sites (I've seen some photos) but I don't know of any tests.


marc801


Aug 13, 2012, 10:28 AM
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wivanoff wrote:
I don't see any reason why an EDK in webbing wouldn't be ok for a rap anchor in the circumstances you describe. I'd use it. I think it's been discussed on Canyoneering sites (I've seen some photos) but I don't know of any tests.
Canyoneering has some of the most sketch anchors I've ever seen. While some techniques would be good for climbers to know - eg: the biner block - others are less than inspiring.

Braced log anchor in Engelstead Canyon:




How solid is that chockstone?




Rapping off a pile of stacked rocks:




sbaclimber


Aug 13, 2012, 10:43 AM
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Re: [marc801] knotting slings with overhand knot(s) [In reply to]
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marc801 wrote:
Braced log anchor in Engelstead Canyon:

Yup, I'd trust it...


marc801 wrote:
How solid is that chockstone?

Looks pretty good to me...


marc801 wrote:
Rapping off a pile of stacked rocks:

Yeah...um....f*** that!


(This post was edited by sbaclimber on Aug 13, 2012, 10:46 AM)


wivanoff


Aug 13, 2012, 10:47 AM
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marc801 wrote:
Canyoneering has some of the most sketch anchors I've ever seen. While some techniques would be good for climbers to know - eg: the biner block - others are less than inspiring.

LOL.. those ARE some sketch anchors. I bet a lot of climbers have rapped off some pretty sketch anchors, too. Well, maybe not as bad as the pile of rocks....

Is the point of your post that the EDK should not be used in webbing for a rap anchor? Or that a DFK is the wrong knot for webbing?


(This post was edited by wivanoff on Aug 14, 2012, 4:06 AM)


sbaclimber


Aug 13, 2012, 1:58 PM
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Re: [wivanoff] knotting slings with overhand knot(s) [In reply to]
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Others may be of a completely different opinion, but I *personally* (caveat, I have absolutely no scientific evidence to back this up!) think that an overhand knot is about equivalent with the chock-log anchor shown above. Good enough for a one-time rap, but should definitely be re-checked before every rap and preferably be replaced with with something more trust worthy asap!
IMO, an overhand is *probably* good enough in a pinch, but if you have the time / hands free, go with the dfk.


snowfall


Aug 13, 2012, 2:40 PM
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Love the anchors, no way not sketch at all! But the guy in pic 2 with the whipped cream on his head -- I just don't get it


USnavy


Aug 13, 2012, 2:49 PM
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Re: [sverris] knotting slings with overhand knot(s) [In reply to]
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I tested an EDK knot in 1" webbing a while back. The knot capsized at about 1400 lbf, which is about 1/3rd of what you would get if you were to use a water knot. I left a 3" tail which was not sufficient to keep the knot tied - the knot came untied after the roll. Keep in mind though, it was a slow static pull with the strands being pulled completely in parallel. The knot may capsize at lower loads in the real world. Accordingly, I would not advise using the EDK to join strands of webbing, especially when the tail is short. Whenever I see fixed slings tied with an EDK knot, I cut them off or retie the webbing with a waterknot. Don't take shortcuts, do it right, use a waterknot.


wivanoff


Aug 13, 2012, 3:14 PM
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USnavy wrote:
I tested an EDK knot in 1" webbing a while back. The knot capsized at about 1400 lbf, which is about 1/3rd of what you would get if you were to use a water knot. I left a 3" tail which was not sufficient to keep the knot tied - the knot came untied after the roll. Keep in mind though, it was a slow static pull with the strands being pulled completely in parallel. The knot may capsize at lower loads in the real world. Accordingly, I would not advise using the EDK to join strands of webbing, especially when the tail is short. Whenever I see fixed slings tied with an EDK knot, I cut them off or retie the webbing with a waterknot. Don't take shortcuts, do it right, use a waterknot.

Thanks for that test. I did not see any tests of an EDK in webbing posted online.

Was your 1400 lbs in a loop or single strand?

If the EDK was in one leg of a loop and you measured 1400 lbs, does that mean the EDK rolled at only 700 lbs? OTOH, if the EDK in webbing was tested on a single strand, does it make sense that loop strength would be 3200 lbs before rolling?

Just curious, really not advocating that people routinely start doing this.


marc801


Aug 13, 2012, 3:46 PM
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Re: [wivanoff] knotting slings with overhand knot(s) [In reply to]
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wivanoff wrote:
Is the point of your post that the EDK should not be used in webbing for a rap anchor? Or that a DFK is the wrong knot for webbing?
* While the EDK in webbing will work in a pinch and USNavy's test shows adequate but not overly inspiring strength, I'd vastly prefer and use a water knot in all but the most dire of time-critical emergencies.
* The DFK uses far too much webbing and takes longer to tie than a water knot - both good enough reasons to not use it for an anchor that will be left behind.


USnavy


Aug 13, 2012, 8:55 PM
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wivanoff wrote:
USnavy wrote:
I tested an EDK knot in 1" webbing a while back. The knot capsized at about 1400 lbf, which is about 1/3rd of what you would get if you were to use a water knot. I left a 3" tail which was not sufficient to keep the knot tied - the knot came untied after the roll. Keep in mind though, it was a slow static pull with the strands being pulled completely in parallel. The knot may capsize at lower loads in the real world. Accordingly, I would not advise using the EDK to join strands of webbing, especially when the tail is short. Whenever I see fixed slings tied with an EDK knot, I cut them off or retie the webbing with a waterknot. Don't take shortcuts, do it right, use a waterknot.

Thanks for that test. I did not see any tests of an EDK in webbing posted online.

Was your 1400 lbs in a loop or single strand?

If the EDK was in one leg of a loop and you measured 1400 lbs, does that mean the EDK rolled at only 700 lbs? OTOH, if the EDK in webbing was tested on a single strand, does it make sense that loop strength would be 3200 lbs before rolling?

Just curious, really not advocating that people routinely start doing this.
The knot was actually end to end, not in a loop. However, the biggest concern is that the true strength of the knot seems to be heavily dictated by how tight it is. I pretightened the knot really well before pull testing it. Had I just loosely tied it and called it a day, I suspect it would roll at lower loads.


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