Author Topic: Knot Development  (Read 8907 times)

SS369

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Re: Knot Development
« Reply #30 on: March 06, 2014, 03:05:47 AM »
Good day Gene.

Looks like you've come up with a double slipped Prusik knot. It shares a bit of the ability to resist lengthwise sliding on a round pole or another rope (size dependent), though more effective in one direction only.

Trying it out with small diameter Dyneema I would say that this is not the best knot for this type of material as it will pull the bight through, which I was able to do with a hand and foot pulling test arrangement.

If adding a lock of some kind after the knot, I would recommend to cinch it all down hard before the add on lock. Especially if using soft media.

I imagine that if the tension to be released were still very heavy, the slips may not pull loose too easily. Additional initial round turns could help with this.

Thank you for contributing.

SS

Dan_Lehman

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Re: Knot Development
« Reply #31 on: March 06, 2014, 07:57:06 AM »
Looks like you've come up with a double slipped Prusik knot.
Slipping a Prusik hitch takes one into philosophical
territory (like "one hand clapping", but with cordage)!
In any case, it is a more mundane version of the
rolling hitch --cow vs. clove orientation
of the closing part-- that we see here, with the usual
sort of slips one might figure given some knot knowledge,
as Xarax remarks.

Quote
Trying it out with small diameter Dyneema I would say that this is not the best knot for this type of material as it will pull the bight through, which I was able to do with a hand and foot pulling test arrangement.
Ah, from inspection of images only, I wondered
at this vulnerability --that what I call the "frame"
wasn't small enough to enable the toggle a sure
hold of the slip-bight.  (This is a problem with the
over-popularized (uncritically) highwayman's hitch,
btw.)


--dl*
====

ps : Wow, I'm really impressed by the soooooooo exacting
file sizes!!  (I'm happy if I sneak in a 90ish kb file under the
limit; but, here, you've got 99 and fractions!)   :D

GeneJohnson

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Re: Knot Development
« Reply #32 on: March 06, 2014, 01:41:16 PM »
To be perfectly honest, I did wind up with a pic that was exactly 100 kb.  I chose to reduce it for fear of pushing the envelope.  Lol

Gene Johnson

GeneJohnson

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Re: Knot Development
« Reply #33 on: March 06, 2014, 03:27:35 PM »
I fully agree, that one weakness that quick release knots of this type share, is having the slip-bight "slip" under the frame, or "catch" if you will.  It is for this reason that I only used two initial wraps instead of three.  A third wrap lengthened the "catch" which would weaken its hold of the slip-bight.  As mentioned in a previous post, it is imperative to fully tighten this knot to maintain its integrity.  Also, as I had mentioned, a HH or "night hitch" should be applied to quick release knots as a safety measure, any time the knot is to be utilized for longer than a temporary length of time.  The night hitch actually serves two purposes.  It prevents the unintentional releasing of the knot and it adds "bulk" to the slip-bight, just under the  "catch".  ( I like to refer to this HH as a "catch lock" )  Please refer to enclosed picture.  Because the integrity of this knot relies on the tension provided by the SE, I would be judicious of its use.  As with several other quick release hitches, I would only use this knot for "temporary" applications.  For "permanant" applications, there are certainly more suitable knots.  Best regards!

Gene Johnson

SS369

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Re: Knot Development
« Reply #34 on: March 06, 2014, 07:48:02 PM »
Looks like you've come up with a double slipped Prusik knot.
Slipping a Prusik hitch takes one into philosophical
territory (like "one hand clapping", but with cordage)!
In any case, it is a more mundane version of the
rolling hitch --cow vs. clove orientation
of the closing part-- that we see here, with the usual
sort of slips one might figure given some knot knowledge,
as Xarax remarks.

Quote
Trying it out with small diameter Dyneema I would say that this is not the best knot for this type of material as it will pull the bight through, which I was able to do with a hand and foot pulling test arrangement.
Ah, from inspection of images only, I wondered
at this vulnerability --that what I call the "frame"
wasn't small enough to enable the toggle a sure
hold of the slip-bight.  (This is a problem with the
over-popularized (uncritically) highwayman's hitch,
btw.)
--dl*

Nice, a difference of perception. Makes the world go round.

Well, I'll stand by my statement as it does look like a double slipped Prusik, to me, not a reoriented rolling hitch that might be double slipped. Further, it does act like a Prusik in that it does resist lengthwise pull.

The vulnerability that I mentioned pertains to the test media (3mm Dyneema) that I used for evaluation, along with other ropes and cords. This cord is very strong and slippery, as you may know, but it is also very compressible being a loose 12 strand braid. So it deforms greatly and can fold very tight and small. The area where the first slip's bight is pulled tight against the second slipped bight's two diameters is where I am showing the pull through. Look at the attached and modified OP's photo.
The half hitch lock can mitigate this some, but I was using the original offering to evaluate.

This could indicate an area of concern with "normal ropes" if the strain were great enough.
So it just bears mentioning, because it is there. Even if it is a temporary application (that may get forgotten for a time). Otherwise I think it is useful and I personally like the capstan effect it uses for maintaining tension while the rest is tied off.

Thank you Gene.

SS

GeneJohnson

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Re: Knot Development
« Reply #35 on: March 07, 2014, 12:18:25 AM »
Thank you much for your input on this knot.  First, let me state that although this knot does mimick the right side of a Prusik Knot, that is where the two knots part company.  The WE of this knot ( left side ) has the sole function of providing a locking mechanism.  If not mistaken, the SE and WE of the Prusik Knot are both used in unison, this being a symmetrical knot.  Although my intent was to design a hitch with a primarily perpendicular pull, it would be interesting to see if it does indeed have a use for lateral gripping and pulling ( right hand side only ).  Allow me to  ask for your opinion.  I have seen Half Hitch Locks applied using the SE of the rope instead of the WE.  The benefit is that the load is spread out throughout the knot and the "Slipped Bight Syndrome" is alleviated.  The downside is that the proper size cordage would need to be used so that the HH can be easily removed.  The other downside is that slack on the SE needs to be present to remove the HH.  Your thoughts would be greatly appreciated!  Regards.

Gene Johnson

SS369

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Re: Knot Development
« Reply #36 on: March 07, 2014, 12:50:11 AM »
Hi Gene, you are welcome.

The knot does mimic a Prusik knot and doing a quick and dirty test it performs like one. It will grip and hold my body weight in either direction. That said, the release-ability suffers quite a bit I suspect from the one side loading. I won't recommend this for a slide and grip use for climbing. ;-) And I know you didn't propose it that way.
I did not intend to veer from the thrust of your thread with this, I just thought you'd be interested in what another mind found.

Knots can be size/type-of-material dependent and not everyone has every type or size, so it is good to bring them to a world wide forum to get opinions and insights.

Using some very large and stiff aborist bull rope (3/4 inch that won't hardly make a 3 rope diameter circle) I found that this a very fiddly knot to tie and the slip portion is "spring loaded" and does not invite a secure feeling. But that is with this rope.
And I didn't bother to try using the last bight as a half hitch lock. Does Anaconda come to mind? Yes.  :)

SS

GeneJohnson

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Re: Knot Development
« Reply #37 on: March 07, 2014, 02:58:29 AM »
Thanks again for your insight.  I am glad that you brought up the fact that knots can be rope size and type of material dependent.  That alone can make an otherwise good knot for one type of rope an unsuitable knot for another.  That being said, what would you recommend for a "multi-purpose rope" knowing full well that it would be a happy medium, such as an "all terrain tire"?  Granted that climbing and marine types of rope are pretty application specific, I am curious in what a good choice for a general purpose rope would consist of, both size and composition.  Your feedback is greatly appreciated.  Thanks again!

Gene Johnson

SS369

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Re: Knot Development
« Reply #38 on: March 07, 2014, 04:05:44 AM »
Gene, that could and would depend on a few usage factors.
What will be the field of greatest use? Marine applications? Carry in your truck for lashing down loads? Just to tie with for tying sake? The list goes on....

If I had to pick just one "do all" rope, I believe that I would choose a dynamic climbing rope. I would choose one that is supple with a diameter of around 10mm. They are generally good against abrasion and hold knots fairly well.  ;D
But, really, how can someone only have one rope? It just isn't enough! ;)

Hopefully others will write in on this question.

SS

GeneJohnson

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Re: Knot Development
« Reply #39 on: March 07, 2014, 04:30:33 AM »
I guess the rope that I am looking for would be something suitable for a "bug out bag".  It would have to be reliable for rescue work as well as unforseen use in a survival situation.  I do agree that having just one rope is a pretty tall order.  Perhaps, two ropes of various composition may span a broader spectrum.  Opinions appreciated on this one.  Thanks!

Gene Johnson

SS369

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Re: Knot Development
« Reply #40 on: March 07, 2014, 03:51:13 PM »
Good day Gene.

I can personally recommend the products from this manufacturer > http://bluewaterropes.com/product-category/ropes/
I own many of their ropes and cords.
I currently use the ProTac 10.5mm in black as my go to rope. It is a static rope and though it is low stretch I find it is not without stretch, just not as much as a dynamic rope.

So if I was procuring just one, as you say "bug out" rope, this would be my choice to cover almost all bases. Larger diameter might be better, but personally I don't think I'll tow and tanks with it.  ;) And if I did I'd double it.

I'd be happy to continue this part of the thread using PM if you'd like so to keep from further diluting the content of this one.
Or you could start a new subject thread if you'd like.

SS
« Last Edit: March 16, 2014, 04:02:10 PM by SS369 »

GeneJohnson

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Re: Knot Development
« Reply #41 on: March 07, 2014, 05:37:07 PM »
Agreed, and thanks for the lead!

Gene Johnson