Author Topic: Matthew Walker / True Lovers / Lanyard as a Compact Bend for Prusik Loops  (Read 442 times)

Moss

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My question is this: Is the Matthew Walker / True Lovers Knot secure as a bend?  It seems to be, as it is based on interlocking overhands.

I would like to use this knot for creating permanent loops in accessory cord for prusiks or a backup sling. 

I had been using a double fisherman's knot, as this is the standard presented in rock climbing manuals.  Perhaps the double fisherman's is stronger, but this knot would be more compact and no more impossible to untie after weighted significantly.  The reason compactness is advantageous in a prusik loop is it avails more space to make a loop while keeping the connection as short as possible - so it doesn't interfere with other connections.

This Matthew Walker / True Lovers Bend (I don't know what to call it exactly) is verifiable, with a characteristic spiral shape.

Thanks for your thoughts.
« Last Edit: September 05, 2019, 02:14:59 PM by Moss »

agent_smith

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Re: Matthew Walker / True Lovers / Lanyard as a Compact Bend for Prusik Loops
« Reply #1 on: September 07, 2019, 03:46:36 AM »
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My question is this: Is the Matthew Walker / True Lovers Knot secure as a bend?  It seems to be, as it is based on interlocking overhands.
It appears that you are referring to #1426 (twofold Overhand Bend).

This question has been asked before in this post by our friend and colleague Scott: https://igkt.net/sm/index.php?topic=1098.0

Scott's question was never fully answered (I think) - and it seemed to drift off-topic and somehow ended up becoming a discussion of #1425A Riggers bend.
NOTE: There discussion drifted to how #1425A was derived...to which I now believe that Phil Smith discovered his 'Riggers bend' from #1053 Derived Butterfly bend.

Anyhow, back to your question...
Quote
I would like to use this knot for creating permanent loops in accessory cord for prusiks or a backup sling.
I think you mean to create a permanent round sling - which can then be used to tie various slide and grip hitches.
Answer = Yes
For me personally, I have (over the years) drifted more toward using the Zeppelin bend as my 'go to' knot for forming a round sling.

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I had been using a double fisherman's knot, as this is the standard presented in rock climbing manuals.
#1415 Double Fishermans bend is inherently secure but jams solid.
Yes - it is well suited as an end-to-end joining knot for bends used in life critical applications.
The reference to rock climbing manuals is always dubious - as most are inaccurate and/or have incorrect concepts parroted from one author to the next.

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Perhaps the double fisherman's is stronger, but this knot would be more compact and no more impossible to untie after weighted significantly.
The reference to "strength" is entirely irrelevant.
There is no load that a climber (of trees or rock or whatever) can generate that will reach the MBS yield point of any knot. The concept of strength is an urban legend...one for the myth buster TV series.

In terms of 'footprint' (ie size/volume) - yes, #1426 has a smaller footprint than #1415.
So if the footprint of an end-to-end joining knot was an important factor, then #1426 would definitely offer an advantage in that respect.

In terms of jamming - it is well understood that #1415 jams solid, to the point where even the use of tools may not yield success in untying (damage would result in the process).
#1426 jamming threshold has not been properly investigated in peer reviewed load testing. Only hobbyist/enthusiast (ie 'backyard') style testing has been done. I myself have not investigated #1426 vulnerability to jamming - however - it does appear that the structure will jam. A control would need to be used to probe this - likely that #1415 could be used as a control.
I note that application of load does disturb the geometry of #1426 - in that it does not maintain its original dressing/symmetry and some segments begin to separate. But, this separation may be trivial - and security is maintained.

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The reason compactness is advantageous in a prusik loop is it avails more space to make a loop while keeping the connection as short as possible - so it doesn't interfere with other connections.
I think you mean that #1426 enables a smaller diameter round sling to be tied (ie a smaller diameter than can be achieved with #1415).
In terms of "interference" with other connectors/components in your rope suspension system, it is possible to purchase small sewn web slings.
If you wanted an absolutely tiny link - have you considered using a metal chain link (ie cut a S/S chain to obtain just one link). Or a maillon rapide?
Perhaps you need your round link to be 'soft' - and not 'hard' (ie metal)?
Obviously, a chain link or a maillon rapide is a hard metal link.

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This Matthew Walker / True Lovers Bend (I don't know what to call it exactly) is verifiable, with a characteristic spiral shape.
The concept of "verifiable" has been parroted by several authors (I might add - by me too!).
This concept can only have meaning to a person who has the ability to recognize a distinctive pattern/geometry.
Also, for the rope solo climber (tree/rock), one assumes that the person is competent and able to perform the 'verification' in isolation.
In a party of 2 climbers (tree/rock) - one person might recognize the knot geometry and thus 'verify' it - while the other might not. Who wins the argument? Presumably, in a party of 2 or more - there is usually varying levels of knowledge, skill and experience. Can the least experienced member of the party override the most experienced member on account of not being able to identify/verify a particular knot? What this boils down to is confidence. A practitioner is either 100% confident or not. In the field, there are usually no reference manuals to refer to or templates to compare against. Its all done from memory. Unless of course a person has a cell phone with internet connection and can pull up an image of the knot to view on screen (although this too may be unreliable).

Dan_Lehman

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Re: Matthew Walker / True Lovers / Lanyard as a Compact Bend for Prusik Loops
« Reply #2 on: September 07, 2019, 04:26:36 PM »
My question is this: Is the Matthew Walker / True Lovers Knot secure as a bend?  It seems to be, as it is based on interlocking overhands.

I would like to use this knot for creating permanent loops in accessory cord for prusiks or a backup sling.
I'd like to see it put through some heavy-loading
tests; I'm skeptical about its stability.

I's also like to see the double harness bend tested;
it's like the grapevine in security, but a bit trimmer.
Both of these knots well guard against abrasive knocks
& rubbing, which some other knots might more expose
vital parts too.
As for strength, part of what makes some knots look
strong in a SLING, on first/only loading-to-rupture,
is that they yield more material into the knotted
side of the sling and thereby can achieve --via the
friction at test pins (more than you'd expect!)--
the anomalous load distribution of say 100% + 70%,
resp. unknotted + knotted halves!  (rather than
what one might reason should just twice the
weaker side (2 x 70% = 140% vs. 170%, here).
THIS IS MY SPECULATION (and some others'),
and i.p. the particular % given here is for example.


Btw, I've never read about any *rule* to retire a sling
fallen upon.  There is advice about retiring lead ropes
after "big falls", but I don't think I've ever read/heard
advice to replace the sling that captured the fall (which
material should have held the greater force!
((And where such replacement is much cheaper!!))
).
!?


--dl*
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« Last Edit: September 13, 2019, 09:27:41 PM by Dan_Lehman »

Moss

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Re: Matthew Walker / True Lovers / Lanyard as a Compact Bend for Prusik Loops
« Reply #3 on: September 12, 2019, 02:57:11 AM »
Thanks for the input.  After further consideration, I'm inclined toward the single fisherman's for my purpose.

The footprint of the single fisherman's is as small as the twofold overhand bend and smaller than the stitched area of a sewn sling.  The twofold overhand bend does deform in paracord and doesn't seem to jam as much as the single fisherman's.  However, I want my knot to jam (and retain its shape).

I use this cord round sling for an autoblock rappel backup attached to my harness leg loop.  Shorter is better, so that the autoblock can't reach the rappel device.  I might also use it as an extender if I run out of sewn slings.

Dan_Lehman

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Re: Matthew Walker / True Lovers / Lanyard as a Compact Bend for Prusik Loops
« Reply #4 on: September 13, 2019, 09:29:32 PM »
... doesn't seem to jam as much as the single fisherman's.
And like this is the water/ring knot.
Some folks have recommended placing the sling knot
in the crossing part of the Prusik hitch. so to help
keep that knot manageable --YMMV.


--dl*
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