Author Topic: Double (and greater) clove hitch  (Read 19177 times)

SenzuBean

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Double (and greater) clove hitch
« on: February 25, 2015, 12:58:58 AM »
Hello IGKT,

I've been thinking about clove hitches, and in particular if there is an easy way to modify it in a simple way to increase its security. There are some cases in climbing where tying a clove hitch with dyneema/spectra (or nylon) tape could be useful, for example [a new method of equalizing anchors called the equalette]. But due to the fantastic quality of dyneema to slip, clove hitches don't work very well. So I thought on it for a while, and I came up with the relatively simple approach of adding two further wraps on each arm.

This is how a clove hitch is tied for climbing purposes (not sure of the name - but when you have access to the end of the bar and can throw it over). https://www.youtube.com/watch?v=Ig4s1sdAHXs
[best to have it on mute]

So instead of a single loop each time, just make a double loop (or a triple). Sorry for no pictures, coming later.

Anyway, I'm wondering if anyone wants to test if these variations would hold better in dyneema. My guess is that they would, but not majorly. Alternatively if anyone has any other suggestions to make a clove hitch stronger (I've seen triple clove hitches mentioned a few times), that would be interesting too.

xarax

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Re: Double (and greater) clove hitch
« Reply #1 on: February 25, 2015, 01:37:24 PM »
  By adding more turns, the security ( regarding slippage ) of a multi-turn Clove hitch is enhanced, for yet another reason : due to its increased inclination, the oblique riding turn drags the first and the last turn towards the middle of the coil. By this, all the adjacent turns are pushed against each other, the friction between them becomes significant, and so the knot is "locked" internally. 

1. http://igkt.net/sm/index.php?topic=4139.msg25019#msg25019
This is not a knot.

SenzuBean

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Re: Double (and greater) clove hitch
« Reply #2 on: February 25, 2015, 05:30:54 PM »
Thank you for providing pictures xarax! I had a search (brief however) and didn't find anything here.

Just wondering specifically about dyneema however. From the discussion on non-slipping bends in dyneema, it seemed that the hypothesis that emerged was that EStar stopper and other successful dyneema knots worked through a tight nipping structure of the tail (I think it was, from memory), and not large amounts of friction as was hypothesized.

SenzuBean

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Re: Double (and greater) clove hitch
« Reply #3 on: February 25, 2015, 06:01:17 PM »
Actually some cursory looking has found some testing has already been done: http://dmmclimbing.com/knowledge/slings-at-anchors/

The table shows dyneema is not appreciably different to nylon, but still performs differently to the other methods (I have yet to watch the video to see exactly what they're doing).


Dan_Lehman

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Re: Double (and greater) clove hitch
« Reply #4 on: March 03, 2015, 11:07:36 PM »
... for example [a new method of equalizing anchors called the equalette].
Subsequent to all the hoopla about this --which IIRC came
via a Rockclimbing.com thread (maybe no longer readily
accessible via that site, which has changed of late?)--,
there was some further testing that indicated little or no
gain for all the machinations.  (Subsequent to the assertions
made in the 2nd edition of John Long's Anchors book.)

Quote
But due to the fantastic quality of dyneema to slip,
clove hitches don't work very well. So I thought ...
And so, too, I thought!  But someone on RC.com or maybe
it was "The Taco" (Supertopo.com) posted results/assertions
of testing cloved Dyneema slings to decent rupture forces,
w/o slippage; and that there is significant nylon in these things
(though I don't think that that fact is at all evident in advertising)!?

Quote
... the relatively simple approach of adding two further wraps on each arm.

I'd rather put a stopper knot in the tail.

--dl*
====

Sweeney

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Re: Double (and greater) clove hitch
« Reply #5 on: March 04, 2015, 01:32:46 PM »
............of testing cloved Dyneema slings to decent rupture forces,
w/o slippage; and that there is significant nylon in these things
(though I don't think that that fact is at all evident in advertising)!?

This is an interesting video from DMM in N Wales showing tests on Dyneema and nylon slings:

http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/

SenzuBean

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Re: Double (and greater) clove hitch
« Reply #6 on: March 10, 2015, 06:41:25 PM »
Here's another simple way to bulk up a clove hitch. No idea if it's any good (all of these ideas would need solid testing). It's method of construction is just to add an extra half-hitch when tied with loops. It can be extended to as many stacked clove hitches as you'd like (although it sits more awkwardly with each). Also no idea of the name - does it have one? It seems a bit more than just a clove-hitch with extra half-hitch, as removing a half-hitch from the other side of the knot results in a normal clove hitch again, implying that the new half-hitch is no less important than the old ones.




Knutern

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Re: Double (and greater) clove hitch
« Reply #7 on: March 10, 2015, 08:07:47 PM »
Are the constrictor knot out of question for any reason?
I'm aiming for knots that is secure, AND that is easy to untie.

SenzuBean

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Re: Double (and greater) clove hitch
« Reply #8 on: March 10, 2015, 08:15:27 PM »
Knutern - not really. I was looking for a knot system that could be adjusted to suit the needs at hand (for example when using prusik-type knots, you can adjust the number of turns for the amount of friction - I was looking for something similar).

As a side-note, I tied a double water bowline:
It was very difficult to cinch (all 4 strands needed to be pulled), and it was hard to tie. But it did look pleasing. Not recommended at all.

SenzuBean

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Re: Double (and greater) clove hitch
« Reply #9 on: March 10, 2015, 08:33:57 PM »
Quote
Subsequent to all the hoopla about this --which IIRC came
via a Rockclimbing.com thread (maybe no longer readily
accessible via that site, which has changed of late?)--,
there was some further testing that indicated little or no
gain for all the machinations.  (Subsequent to the assertions
made in the 2nd edition of John Long's Anchors book.)

Very interesting - any references would be appreciated.