International Guild of Knot Tyers Forum
General => Chit Chat => Topic started by: DerekSmith on September 29, 2006, 12:34:03 AM
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I have been interested in the numerous friction hitches we have at our disposal. Claims are made for each including the amazing claim made for the Icicle Hitch that it can hold fast to a tapered spar.
Examination of the various hitches showed that they tended to have similar conformations. They would have a load application section, a set of coils for grip and an anchor. Generally the anchor is formed by taking a line from the anchor, down, across the coil to clamp the the anchor and the coils in place, to the load tension point.
Generally the limitations of these various knots stemmed essentially from the clamping line pulling the whole knot forward and failing it.
The knot presented here was designed purely from principle and to this end, if the knot has not already been documented and classified, then I would like to name it the "KC Hitch" - in honour of the person who tries relentlessly to educate us all into the world of knot leverage. This knot is based on two principles. The first is the Power of Wrapped friction law perfectly explained by Roo_Two on his web page http://www.geocities.com/roo_two/friction.html . This law describes how a small holding force is increased exponentially with the angle of contact - roughly to the power of three times the coefficient of friction for every complete turn.
The second principle is that of Angled Leverage - continuously promoted by KC. This principle shows us that small tangential movements of a line away from the shortest path have a huge mechanical advantage approaching infinity as the line is first starting to be moved away from the shortest path. Most of us will have utilised this principle, tightening a load by pulling sideways on a rope or by standing on a towline to budge an obstinate load.
Both of these principles are at work in all of the documented friction hitches, however, in designing this knot the principles were used to create the knot form rather than happen by accident by trial and error tying of cord. As a consequence, this friction hitch should be approaching the optimum for friction hitch abilities. However, only stringent Peer Review and in field use will show if theory alone has given us a better friction hitch.
The Design Stage.
The Wrapped Friction Law can only amplify a gripping force, so any use of this law must start with a finite gripping point, so the knot must have three sections or functions:-
Part 1 : The anchor - this will provide the embryonic gripping force which will be amplified by the coils.
Part 2 : The gripping engine - this will utilise coils to exponentially amplify the anchor grip to the level needed to hold the object and transfer all the working force into the held object.
Part 3 : The force engine - this will allow the applied force to be transmitted into the knot, to tension it and to allow for surface geometry and movement of the knot.
To start then, I used the best gripping anchor I know - the Constrictor. I tied a constrictor onto a length of dowel and yes it was able to generate a small gripping force which could be fed into an amplification coil. Note, this is friction around the dowel NOT along it. The line from the constrictor was then wound around the dowel and exactly as predicted, the gripping force rapidly amplified within just a few turns. Even tying this construction on a glass bottle it was easily possible to add turns until the small holding force from the Constrictor had been amplified to a level sufficient to grip the glass.
Of course, this is grip tangential to the dowel and this hitch must create grip in line with, i.e. along the dowel. This was easily achieved by driving a pin into the dowel and turning the cord 90 degrees around the pin so that the gripping force now ran along the dowel. Of course, we cannot rely on banging pins into object just to make our knots work - this knot would have to provide its own means of turning the direction of grip through 90 degrees. The solution is of course an easy one. The second line coming out of the constrictor was simply wound in a counter spiral through the first and the two ends joined. In this manner the two coils work together to turn the gripping force through the necessary 90 degrees.
Finally the force or tensioning engine. As the loading force is applied to the knot, the first turns start to open up - concertina fashion. In doing so, the cord is forced to lengthen and the force of creating this stretching is transmitted through the cord back into the knot itself. This linear tensioning of the knot cord massively increases the coefficient of friction and is transmitted right back to the anchor Constrictor further tightening it and increasing the anchor grip being made available to the gripping engine coils. The more elastic the cord is or in cases of very low friction, several of the turns might be forced to open in order to generate sufficient line tension within the knot.
And there you have the prototype "KC Hitch". It is highly functional, it can grip glass even with Spectra cord and it can hold firm onto a taper. There is a limit to the angle of taper this knot can hold and this limit happens when the diameter of the taper narrows faster than the line extension caused by opening the loops. When this angle is reached, the knot will never hold and will always simply run off the taper. However, at angles below this critical angle, line tension is increased as the loops open up and given sufficient turns, any surface can in theory be held.
Optimisation
The prototype "KC Hitch" is highly functional, but as a working knot it is a real pig to tie and so is unlikely to ever move into mainstream use. It was notice during trials with various cords and binding surfaces, that movement of the last two coils rarely occurred and that the tensioning effect caused these coils to lock tightly onto the load surface. This meant that the coils could act as their own anchor thereby dispensing with the need to tie a Constrictor around the load. This proved to be the case and led not only to a simplification in the construction of the knot but also to an extremely simple method of tying it.
Here then is the final field ready "KC Hitch"
Take the line and start with a working length sufficiently long to make the required number of turns around the load. For high friction loads four is sufficient for low friction (glass, polished wood etc) eight may be necessary.
Hold the cord against the load with your thumb
(http://igkt.pbwiki.com/f/KC%20Hitch01%20sml.jpg)
and wrap the working end around the load in an open spiral ( say three or four turns while you experiment with this hitch).
(http://igkt.pbwiki.com/f/KC%20Hitch02%20sml.jpg)
Then start wrapping the cord back over the first spiral so the cords cross front and back of the load.
(http://igkt.pbwiki.com/f/KC%20Hitch03%20sml.jpg)
When you get back to the start, tie the ends together using whatever knot you prefer, even the Reef will do here as its only function is to hold the ends together.
(http://igkt.pbwiki.com/f/KC%20Hitch04%20sml.jpg)
slide the coils up together and take out the slack.
(http://igkt.pbwiki.com/f/KC%20Hitch05%20sml.jpg)
Apply tension to the load and the first coils will open and tighten up the knot. If there is a lot of slack taken up, then close up the loops again and remove the slack before reapplying the tension.
(http://igkt.pbwiki.com/f/KC%20Hitch06%20sml.jpg)
The objective is to have at least the last two turns (the anchor turns) remain closed under full load conditions.
(http://igkt.pbwiki.com/f/KC%20Hitch07%20sml.jpg)
Observations
This knot uses leverage to apply tension and that leverage is very powerful. I have seen samples where 500# Dynema has bitten into the surface of a glossy dowel - it did not slip, but it sure bit in. As a consequence, you need to be sure that you are using rope or cordage of sufficient strength to take these loads. This needs to be considered as a potential weakness of the knot as the leverage is capable of amplifying the applied load to levels in excess of the breaking strain of the cordage used. You might find it advantageous to tie the knot to the load in one cord and then use a different rope to haul with.
The second observation may serve to stimulate future studies, and that is that there is a definite relationship between cord diameter a load diameter and how many coils open during the loading phase.
Conclusion
So there you have it - is it a new knot? Does it work in all applications you test it in? What is your considered opinion of its structure and working parts? Do you feel that the analysis and process was flawed in any way? When does the knot not work and what safety concerns do you have?
Is it now possible for members to give this knot a critical Peer Review as this is surely the prime value of the combined expertise of the people gathered around the IGKT.
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I'd say ABOK1755. In #1756, however, it is suggested that not just crossing the line over itself, but actually reversing directions, is a possibility. I would expect line reversals of this nature to create a larger mechanical advantage as the cord is working against itself. In #1755 and your images, the line will work to rotate the entire body in a given direction, and the only point that counters that rotation is the final holding knot. If instead of just laying the cord over itself, we actually pass it around itself and reverse it multiple times around the pole, it will have nowhere to go whatsoever. Indeed, the final knot still supports the totality of the force, but each wrap would improve gripping ability much more without causing rotation.
As to actual physical measurements and comparisons, I have only made several (and nothing worth publishing), but I will say I'd still expect directional reversal and line crossing to amplify grip much faster than unidirectional coils. The nature of force amplification per coil is also questionable; if it were truly exponential, one would expect you'd be able to use this to break rope after several coils --- alas that this were true.
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Hi Derek,
A splendid try - it does look somewhat like 1755 in ABOK but I think your construction method is a little different in that only one side of your line is tightening over the other all the time, tending as bridog said, to twist the object to which this is gripping. We use a similar construction to 1755 (ABOK 1758) when applying a selvagee to a shroud for tuning the rigging and we take that loop (you could still use a tied piece of line) and wrap it over itself in alternating turns - first the left is passed over the right then the right is passed over the left, so that the load is shared equally (by load here I mean the tension developed along each leg of the selvagee) by both legs and the friction applied is also shared without having to shove each succeeding turn up against its neighbor as you have done. However, I do admire your method - it looks very thorough (of course we still have to hear from Dan L on all the points/line/objects it does not work for) and easy to replicate. I would like to hear of more of this type of application!
Lindsey
PS - I wonder if bridog's method of reversing (I take this to mean the formation of elbows in the pair of lines) the lines will result in point loads instead of spread loads, where the spread loads of your wrap or the wrap I have suggested, maximize friction? Bridog - I agree that it is difficult to see exponential growth here!
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Hi guys,
Thanks for the responses. If it is 1755, then I suppose it just goes to show that nature has a way of inventing the same thing repeatedly?
There are a couple of the issues you raise that I would like to comment on.
First reversal; if by this it is meant that effectively each cord stays on 'its own side' and when the cords meet, they cross and do a 180 degree turn. Then I would say that it is critical NOT to apply reversal. When a cord changes direction by being turned around another, considerable tension is lost depending on the radius and extent of the turn. In the proposed hitch there is not a single reversal within the knot (i.e. after the tie off) and this allows tension generated in the force engine component, to flow through the cords right to the anchor coils. You can test this by seeing how hard the cord in the end anchor coils goes when tension is applied. This compresses the cord in the anchor section onto the load object without placing the coils under any 'in line' tension at all.
If however, by reversal you mean 'priority' i.e. that at the first crossing A is over B, then in the next crossing B passes over A, etc. etc. Then this was the form of winding used in the 'prototype' knot. However, it is cumbersome to tie when you only have access to one end of the cord or the load is long, and in trials, the single priority wrap method showed no loss of performance. In fact, leaving one cord always on top may aid the transfer of tension back to the anchor coils, however, there was no marked indication of this.
Second - the concept of 'Force Amplification per Coil' is wrong. Grip is amplified by the coils, not force. On a slick surface such as the one shown in the example, especially with a slippery braid, getting any level of grip is hard. However, once you have achieved some level of grip, tension in consecutive coils builds this grip at the rate of Euler's constant to the power of the coefficient of friction times the total angle of contact in radians. Tension in the cord however, may be massively increased by the mechanical advantage caused by the coils opening in the 'force engine' part of the knot. Although this is the purpose of this stage, it is also the prime weakness of this knot that it can either break the cord or damage the surface of the object being held if low friction and high dragging force causes too many coils to open. Note: it is not the number of coils that influence this, it is the number of coils that are opened that causes the mechanical advantage.
Finally, the importance of 'shoving the coils up against one another'. The 'diamond' form of the knot works well, and can be used if you do not want the knot to be allowed to develop too much tension through mechanical advantage. However, the mechanical advantage is at its highest when the angle between coils is zero degrees, so closing the coils (and removing the free cord generated) gives the oportunity for greater tension to be created within the knot. If too much tension could be an issue in use, then deliberately leaving the first two coils in 'diamond formation' will dramatically reduce the effectiveness of the the 'force engine' component.
Derek
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I did some experimenting with the 'KC Hitch' today, on broomsticks and aluminium bars, and from the first try it performed very well. Easy to tie and cast off, with little adjustment needed for a ratchet-like grip. It's definately in my list of favourites now. ;D
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Sir Derek i'm honored! :o
And this is my 4th try to respond to this due to computer type problems (and length of response?). Also have much less time available here; and pretty much everywhere!
i think this strategy/ mechanical configuration is less like knots we know better(and thereby their mechanics); and more like a Chineese Finger Puzzle or loose braid/ weave; though following same principals.
Because we pull at both ends of the laced line; instead of 1 like in a Constrictor; we immediately have half as much power/ line tension loaded into each leg and curve. In a Constrictor, full force is initiated on each/ the single leg of it's turns. i've looked at rope as just a hose device that carries/ conducts tension force flow down it so much; we even call an electrical extension cord an 'electric hose' around here!
In this imagery of a rope that is just a hose loaded with not the push of water pressure force; but the pull of tension force; i see a Constrictor's pull on it's host/ mount/ bundle / load is best at perpendicular to this host; for that places the force of it's bends inline/ not perpendicular to the initiating Standing Part's pull. This "KC" hitch is best pulling inline with the host/ mount/ load for this also; pulls most inline with it's bends. It is just that the bend in Constrictor is near Zer0(comes back to Standing Part / Initiating Force, and in KC it is near 180 and extends from there further away from Standing Part/ Initiating Force. So Constrictor pulls perpendicular to mount, and KC inline; reverse scenarios of force flow, giving reverse useage mechanics IMLHO.
Both even give fairly balanced pulls to this direction too. A Constrictor comes in center mast to it's turns, and then flows the rope/ line of force to one side, then the other; before force terminates in center (of hitch) once again. KC/ Finger Puzzle; pulls from both sides of host / mount evenly; then cascades residual forces back and forth fairly balanced; but all ways a net of inline with Standing Part as Initiating Force.
Also thus; Constrictor gives an intense compression/ push inward in one area perpendicular to host/ in a strianght line across it's narrow axis. While KC gives a sock/ glove of pull along the length/ long axis by gripping mass of the host; once again opposite effects. A Constritor's tensile strength is probably, mostly found to be dependant/ degraded by size of host arc i'd think; while KC's strength is mostly the first / most loaded arc of 1 leg of line bending the Standing one; to make both of them a Standing Part/ Initiating pull into the next bend/ arc. Making both ehnds of KC strong eyes to hook directly to Standing Part; without bend in most loaded part of line as most ineeficient point; and more the long arc taken around host; shared betwen 2 lines of pull. It would thus be more of a softly bent basket pull, rather than sharper/ bend around self single leg pull.
In certain ranges to increase leverage on bend/ arc we must use 1 strategy to get maximum tightening and in it's opposite arc range; likewise the opposite tightening strategy; i think. In a bend/ arc close to Zer0 degress/ U shaped; we have 3 positions. 2 ends of the bend (as a mechanical unit) and the bend itself. In this instance/ range; to tighetn more; we anchor one end and pull from the other as input; to get an output of higher leverage at the bend. As in a 2/1; only isde the microcosm of a knot/ lacing.
Notice if we input pull at the bend; instead of the end in a Zer0 degree range of bend; we are just dividng our pull between the 2 ends; at inline angle to the pull. Inline angle to bend being most direct direction/ least leveraged; so am just dividing unleveraged pull. So this is backwards / reducing my pull effort; not increasing it; like pulling from 1 end give output (at bend) increase above effort input.
If however we have a bend/ arc that is of opposite Nature; 180 degrees range/ folding away from Standing Part/ Initiating Force (instead of folding towards SP); then we must apply opposite strategy for most tension i believe. Of our 3 positions, of 2 ends and the bend; we still anchor 1 end; but now anchor the other/ or place on load/ host etc.; and input force at the bend; to recieve it at the end (or really both ends) as in Brion Toss's sweating more purchase out of a line. If we pull at the end of this configuration (and not the bend) like KC Hitch does; then i believe we would be losing potential leverage force;as we are inputting at end; when we should input force at bend; and recieve output force at end(s). All theoro-correctable of curse; but the way i see it!
Also, this run to first bend of KC being a contacting one; engages friction; so their is more friction reduction of input/ Standing Part pull going into first bend, than the force in Constrictor at first bend; even if we compensate for the 1/2 force of 2 legs of support in KC Hitch i'd think.
KC Hitch shows 3 bends/ Round Turn as very powerful strategy once again; even as the spiral is elongated out to pull linearly/ inline with host mount and not perpendicularily. If just 1 bend, would push host perpendiculairly. 2 bends but not inline; would twist host/ mount. But 3 bends gives 2 pushing on host in 1 direction, and a center bend; pushing balanced between those 2 points for a more 'stable' grip/ trap on line. Especially noticeable if we take our friction hitch from a non-flexible host mount (pipe, spar etc.) and place it on a flexible host/ mount (rope grip etc.); that can bend in the grip of the KC or similair hitch. Subsequent turns becoming more superfluous; unless mount very slippery i think.
Ummmmmmm i guess my turn is over! :P
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I'd say ABOK1755.
In "The Ashley Book Of Knots" p299 ref #1755, Ashley depicts the following construction:-
(http://igkt.pbwiki.com/f/1755b.gif)
and says of it:-
"1755. A cross-lashed strap made fast in the rigging, to hook a block to. Shakespear terms this method of lashing (differently applied) - cross-gartering"
From the diagram, it is clear that the #1755 described by Ashley is essentially the structure depicted in step four of the production of the KC Hitch. Clearly mariners of the time of Shakespear knew of the value of a cross-gartered lacing and its ability to hold laid rope onto vertical (timber) rigging. However, its structure and the description lead me to believe that its inventors and users had little idea how tantalisingly close they were to a knot of far greater potential (I can but assume that in the materials they were working, the #1755 structure was none the less more than addequate) and for the reasons I will explain, I feel that the KC Hitch remains a new knot, worthy of its own name.
Of the number of hitches recorded by Ashley involving lines which are multiply 'dogged' (i.e. wrapped around the spar), they are all depicted in use in the open (i.e. gartered) configuration (1751, 1752, 1753, 1755, 1756, 1758). Because of this all of these knots have a force vector directly in line with the load, applied through the knot to the top of the knot (the anchor part of the KC Hitch). Doubtless, in the materials of the day, the coefficients of friction were so high that there was no need for a anchor section, nor need to amplify this grip. The gartered body of the knot was more than sufficient to produce all the contact grip necessary for the job. Try this today with braided nylon on chrome tube and the #1755 will slide straight off!!
However, those mariners were tantalisingly close and had they needed the additional grip, doubtless one of them would have stumbled across the process of closing up the lacings before applying the load, and of noting that sufficient coils must be applied to ensure that the last two coils must always remain closed to keep the knot in place. But they didn't need the grip and the "Cross Garter lashed strap" is as far as they got.
So, although the 1755 is close - it is half way there - it cannot perform the same feats of griping made possible by the enhancements which make the KC hitch the knot that it is.
Derek
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ABOK #1755 was the closest contender for the KC hitch.
Now I have come across a bend based on the same structure -- the Albright knot.
Interesting that it works very well when the KC cord is much lighter than the other.
http://www.thaifishingguide.com/fishtechequip/techniques/knots/albright_knot_steps.html (http://www.thaifishingguide.com/fishtechequip/techniques/knots/albright_knot_steps.html)
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Now I have come across a bend based on the same structure -- the Albright knot.
One of the continual problems with the presentation of angling knots is that the
actual, final geometry is obscured (and I guess that this is partly attributableto the
author not knowing what it is!). The part of the Albright knot that superficially
resembles the KC knot is not at all present upon completion--the wraps of the
SPart--which is loaded w/o sharing with the end, in contrast to the KC knot--
will pretty much straighten out and cast all of its wraps into the outer, overwraps,
as your cited presentation shows (though it obscures the SPart, lying beneath).
The Albright is akin to the Blood knot, to Common Whipping.
--dl*
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I called this a French Prusik in a 1967 newsletter article that got expanded into a book in 1973. Bill Plummer's highly mathematical analysis (1963) of it is included in the 1973 book. Paul Hasluck called it a cross lashing in his 1905 book. The US Army rigging manual calls it a telegraph hitch, used for gripping posts while lowering them into holes. The name "telegraph hitch" should give some hint of its age. The name dog and tails is used for a variant where the closing knot is at the unloaded end of the hitch
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The following information from icicleuk.com http://www.icicle-mountaineering.ltd.uk/skills.shtml (http://www.icicle-mountaineering.ltd.uk/skills.shtml) shows the only image I have found for the French Prussic which is often referred to as a French Autoblock / Kleimheist Prussic (presumably stemming from the similarities of these two knots). Neither of these two knots have the garter hatch crossings of the KC hitch.
(http://www.icicle-mountaineering.ltd.uk/images2/knotD.JPG) Kleimheist Prussic
The kleimheist is often the most effective prussic for locking on a rope, and is frequently used for a safety back up on an abseil. The only disadvantages to this knot are that it can lock too well, and be hard to undo, and also all the load weight is on one piece of 7mm prussic cord in a fall situation.
(http://www.icicle-mountaineering.ltd.uk/images2/knotG.JPG) French Autoblock Prussic
This prussic looks similar to the kleimheist, apart from both end loops are clipped into the karabiner, so in event of a fall, the weight is distributed better on the prussic. This knot is very useful in a crevasse rescue hoist pulley system as it can be easily loosened, and can lock off automatically.
However, the Tress Prussic on the same site does indeed show the KC structure.
(http://www.icicle-mountaineering.ltd.uk/images2/k
notF.JPG)Tress Prussic
The tress is the best prussic to use on wet or iced up ropes, a it squeezes the rope to create friction when under load, rather than constricting on itself like a normal prussic. This enables it to open more when not loaded, so it can easily be slid over lumps of ice that have formed on the rope.
However, as Prussic knots are usually put on using a loop, unless this one is put on over the end of the rope, I cannot see how it would have been created using a preformed loop.
Paul Hasluck's description of cross hatchings is reminiscent of ABOK #1755 and either #1755 or the KC hitch would make an excellent 'telegraph hitch'.
As for the 'dog and tails'. That is an excellent enhancement. The weakest part of the KC and the KC Sling Hitch are the closure point. The 'dog and tails' concept removes this weakness to the least stressed part of the knot, i.e. as you put it Bob, to the 'unloaded end' (it's not really unloaded but it is the least loaded).
So, the ultimate way of tying this knot for strength might be as follows:-
Middle the cord and form a cats paw. Place the cats paw over the hauling device (hook, bina, chain ??)
Take the two ends and proceed wrapping the gartering around the spar, load etc.
When enough wraps have been applied to use available friction, close up the garter diamonds and knot the ends tightly (consider a slipped knot for ease of later release).
Apply the load and check that at least the last two coils near the closure knot do not need to open to achieve the necessary grip.
I think this one may well be the hitch to beat !!
Of interest, I have never thought of the KC hitch as being of any use in a cord on cord situation because it deforms the main cable in its attempt to gain purchase. However, having seen it under test, it is acting very much as the plaited double performs, shedding load by latteral compression rather than by constriction, so again the use of this structure in the 'Prussic knot' mode could well prove to be very strong.
http://cmru.peak.org/Rigging/dnt.htm (http://cmru.peak.org/Rigging/dnt.htm)
(http://cmru.peak.org/Rigging/11-1.jpg)
Derek
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'prussic' => 'Prusik' ,
'kleimheist' => 'klemheist'
And I think this has been referred to before, but a good article about fricion hitches (in HTML of PDF) is:
www.google.com/search?q=cache:39oMYLWibwcJ:www.treebuzz.com/pdf/climbing_hitches.pdf+valdotain+tresse&hl=en&ct=clnk&cd=1&gl=us (http://www.google.com/search?q=cache:39oMYLWibwcJ:www.treebuzz.com/pdf/climbing_hitches.pdf+valdotain+tresse&hl=en&ct=clnk&cd=1&gl=us)
*knudeNoggin*
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The name "French Prusik" is ambiguous. I have found at least six hitches by that name. My 1967 article and 1973 book may have been the first publications to describe the "French Prusik". I found the name used in a 1961 rescue report with no description. Heinz Prohaska asked me where I got the hitch and if the French actually use it. I do not know. The name was in common use by thos from who I learned, but they did not know its origin. I bought about a dozen pre-1960 climbing books. None of them have it.
Michael Noonan, in his 1997 book "Climbing Knots for Righties and Lefties", used the name for what I would call a Helical Knot. So did Richard Hopkins in his 2003 book "Knots".
The most recent French Prusik is from Alpine Caving Techniques by Marbach and Tourte. It amounts to a single-strand Bachmann. The name was a choice by the translator. The original French edition calls it a "noeud autobloquant" with carabiner.
The name "Autoblock" for another hitch is a bad translation. The generic French term for these hitches - Prusik, Bachmann, Hedden, etc. - is "noeud autobloquant". I can imagine an English-speaking climber asking a Frenchman "What do you call that?" The French call it a "noeud Machard". I would like to research the origin of "autoblock", but I have not been able to find someone with a 30-year stack of climbing magazines and books.
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Head still not working very well, so please forgive me if this has all been covered in some of the stuff that I didn't follow above, but the knot is familiar to me too in a climbing context, though I have never had a name for it beyond 'plaity Prussik' which was my own coinage, but may have spread beyond the confines of my own small band of belayers (and I certainly didn't make up this knot myself!). My available library extends only to Geoffrey Budworth's 'Need to Know? Knots' that I bought last week - in a bid to stave off insanity - from the excellent Postscript Books (http://www.psbooks.co.uk/BookDetails.asp?Code=38498&pg=Title+Search+Results&ur=SearchResults%2Easp%3FTitle%3Dknots?pgn=1%23Nav38498) for a reasonable ?4.99, but - rather gratifyingly - within he illustrates the same fellow (though secured with a shackle and tied in a sling) on p.162-3 and he calls it the 'slide-and-grip hitch (end-loaded, one-way)'. A catchier title than KC hitch? It will certainly grasp the smooth aluminium of my crutches even when tied in very slick 8mm cord. Budworth, too, suggests the Chinese finger trap comparison.
All these 'Prusik' hitches get their names swapped around fairly frequently, dependent on with whom one is climbing, and perhaps the Guild is the place to firm up the nomenclature once and for all. They each bring something different to the mix, and perhaps a chart of their most appropriate applications might be formed (once one has settled on the names...)
By the way, can anyone tell me how Dr Prussik actually used his knot for repairing instrument strings, and does it work? Does anyone use it thus today? He has spawned a verb in mountaineering, but I've not heard of him in a musical context at all.
I have been very much enjoying another doctor's work - Asher's Bottle Sling! A variant on Prussik Classik (will this term catch on? You heard it here first! Illustrated by Budworth (ibid. p.94-5) which I had not met before, but seems to top the fiendish Jug Sling that I can never remember how to tie.
And to conclude my ramble: Derek, does your interest into the numerous friction hitches extend to the range of slide and grip hitches of the Midshipman's variety? I use these a lot for all sorts of tightening/guy-rope type functions, and it seems to me that almost anything asymmetrical (about the point where the working end meets the standing part) will do, so long as it doesn't shake free - exploiting the opposite effect to your lovely symmetrical hitch above. All the Tarbuck/Midshipman/tautline/rolling hitch family rely on this kinking of the rope-that-is-to-be-gripped, and my own favourite (nameless?) brings the working end back over the SPart in the final half-hitch to run parallel to itself, as it were, for elegance - I'll take a picture if there's the interest, but it requires stair-use, so that's for another day...
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I originally 'designed' the KC Hitch as an enhancement to the the standard hitches in simplicity of tying and maximised grip on tapered or slippery objects. The gartered lacing had been utilised many times before but always open, presumably to spread load, never closed as in the KC where the design was that as line tension increased, the lacing opens up with massive leverage advantage and creates huge grip pressures in the remainder of the hitch.
I had not thought to use it on other cords, indeed when I tested it in the manner of a 'prussic' I regarded it as very poor. In fact, apart from tying a very light line onto a very stout mono, I still do not favor the lacing or braid prussics over the significantly better performing 'wrap' style prussic (I use 'prussic' here in the sense that one would use nescafe, biro or hoover to denote a generic class of objects -- in this case, a knot formed out of lighter line to create an adjustable grip on a heavier line).
Re Bob's post; has anyone else notice that there seems to be a trend in the evolution of the use (and therefore popular meaning) of the term 'prussic' - vis; 'a hitch' is used to tie cord to a solid object, while 'a prussic' is used to tie cord to a thicker line (sliding adjustment incorporated).
Tom; re other friction hitches. It was study of how other hitches worked that led me to consider that they were nearly all flawed? because they mostly took the load straight to the back of the knot which tried to force the knot to slide. When a knot did slip, it was because this loading was pushing the knot down the thing it was fixed to. For a knot to escape this flaw, it had to have a 'safe anchor' removed from the incoming load. My experimentation started with a constrictor as this 'safe anchor', but I soon realised that simple wraps were more than adequate once the exponential friction law of multiple wraps got put into gear.
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I take your point, Derek: all the prussik cord-on-cord discussion (and other climbing prattle) might be considered a digression from your design purpose of ultimate hitch grip isolating pulling force from the anchor. (and thank you for your kind words in another place!) I think it courteous, though, to respect Dr Karl's name - would we be so cavalier with the honoured name of Ashley?
Perhaps this is matter for another strand (thread?) then? If your hitched-to item is solid (and effectively smooth) then inward pressure is all important, but with prussiking, the flexibility of hitched-to rope can be utilised. You have made a fast, simple, and (in terms of its behaviour) reasonably predictable hitch that could indeed pick up an icicle. The heat of friction might even grip the thing more tighly if the anchor melted its way into the icy tapered spar. The Tarbuck/Midshipman/tautline/rolling hitch family would all tend to snap an icicle - as would Prussik, Klemheist &c - with assymmetrical gripping forces, but would they grip a rope more firmly for the same reason? I would guess, also, that much less damage would be caused to the rope by this lopsided bending, than with balanced 'teeth'.
And why so many doctors involved in knotting?
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I think it courteous, though, to respect Dr Karl's name - would we be so cavalier with the honoured name of Ashley?
Then that would be, exactly, 'Prusik'--not 'Prussik', 'prussic', 'prusick', ... & a host of other pretenders.
('Bachmann', 'Hedden', 'klemheist', also, fyi)
::)
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Shame on me for the surplus S! Sorry Karl, and all others I have offended. Although I think the category could be prusik, and the verb prusiking, in the hoovering manner. Would this website be the place for some mighty list of recognised knots, a wee picture, and a hint at the history? It would suit at least one of the original purposes of the Guild, methinks, and might be both Authority and Reference for all in doubt. Establish a format, farm out family sections to various keen folk, quibble here and there before settling once and for all... we'ld be finished in no time!
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Shame on me for the surplus S! Sorry Karl, and all others I have offended. Although I think the category could be prusik, and the verb prusiking, in the hoovering manner. Would this website be the place for some mighty list of recognised knots, a wee picture, and a hint at the history? It would suit at least one of the original purposes of the Guild, methinks, and might be both Authority and Reference for all in doubt. Establish a format, farm out family sections to various keen folk, quibble here and there before settling once and for all... we'ld be finished in no time!
Oh Tom,
I do so like your way of thinking, perhaps a wiki is better than a forum or a 'normal' website for all this activity and occasional quibble.
Have a look at the IGKT.pbwiki, here is an example of one knot page just waiting for user input http://igkt.pbwiki.com/Carrick (http://igkt.pbwiki.com/Carrick)
In order to make contributions to the wiki, you just need to log in using a name and password. If you would like to give it a try, PM me and I will send you the password. Of course, apart from multi user input, the really nice thing about a wiki is that the whole thing is searchable. If you think you know a name of a knot, just key it in the search box and if it exists anywhere in the wiki it will be listed with a little bit of context. Give it a try with vice versa or ampersand.
Derek
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What a brilliant resource! I enjoyed the history of the Ampersand in particular. New to this game, I am not entirely sure what the difference between a website and a wiki is (other than its daft/Hawaiian name), but searchability would be crucial. The problem with a name search is, of course, that you have to know the name! I had envisioned something more columnar - database-stylee - that could be reordered according to what element one required, eg. 'bends', 'pre-1900', 'very strong', 'beginning with L' &c (there's that ampersand again!).
One might even scroll down a column of thumbnail images to try to spot a particular knot.
The trouble with wiki, if I understand it right (and my faculties are severely impaired at present) is authority: if anyone can change things without review, new information would remain unchecked until another happened upon the page that was changed. A chart could show all new info in a different colour for a few weeks until folk had had their say and, indeed, be searchable by 'entries in the last 2 weeks' or some such, but then perhaps have a column for links to further (wiki?) information or more detail.
It was rather daunting for me to ask the Guild whether Tom's Bend was indeed the astonishing advance in knottery that it appeared to be - especially since I had never even visited an e-Forum, let alone posted anything. Some simple, searcheable area to make preliminary investigations would have been welcome. If the burden of annotation were stored elsewhere (though linked) the search would be clearer and faster, and be amenable to statistical inquiry. Oh, what a resource it could become!
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But Tom,
With your knot clutched firmly in your hand and your ideal search facility open in front of you - WHAT WOULD YOU SEARCH FOR???
How would you describe your knot so that it could be searched for?
This is a grail many have been searching for - do you have any ideas????
Derek
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hmmm. I know that many clever folk have been involved in attempts to find a rigorous and unambiguous set of descriptive terms for knots, but the trouble with all is that one has to learn the system before one can describe the knot, and therefore new knotters will still have to post-and-hope to have their wares assessed. The point would not be to pin a knot down by description, but to show that it exists. Salient properties and uses described concisely, and more cumbersome (and subjective) information linked to elsewhere.
Had I my dream facility before me, I could at least narrow the field to 'bends' (saving a lot of work), then 'symmetrical', and then perhaps click away most of the remainder with a glance at a thumbnail, narrowing the field still further. Inevitably there will be some more tedious scrutiny before one could begin to get excited, but at least one would have the assurance that the list was reasonably exhaustive. An ABOK or Budworth encyclopaedia is an expensive tome, and not in every library, but even if these were checked through, doubt would linger.
I think we all assume the list is not finite, but it would seem a worthwhile goal for the guild to, at least, present the current state of knowledge.
The Wikipaedia discussion going on elsewhere in ChitChat hits upon the same question of authority that I mentioned above - the Guild should be the authority! It is delightful to chat about knots, but there is a serious purpose enshrined in the constitution, and a great deal of expertise here to be tapped.
Once a form were established, by farming out small parcels across the Guild, perhaps with 'Fishing'/'Climbing' (or some other type of subdivisions) editors to scrutinise consistency, really a very useful and impressive resource would quickly assemble...
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Hi Tom,
There have been a number of attempts to mobilise some sort of group effort but generally to no avail. It seems the key to getting something done is to set the example and do it yourself, thereby making a facility available to folks as their interest is sparked by the work already done. To a degree this was the intention with the Wiki. Initially there were visitors but no contributions, but over time a number of others have made the jump and started to contribute. It is still very early days but it is starting to grow - take KC's carousel on the front page for example.
My hope is that by empowering people to take action, you might tempt them to do so.
As for your thoughts about grouping knots into activity sections - 'Fishing/ Climbing' etc, one of the really useful recent additions to the Wiki is the use of 'Tags'. Any number of tags can be added to a page and any tag can then be listed to show all the pages it is linked to. Click on 'bend' in the tag list and all the pages tagged with 'bend' are listed. Obviously a knot could be a bend and a loop and a hitch and be used in fishing and climbing - all these tags can be added to a page and used for selecting a subset of pages.
Re your thoughts on 'finding a knot', I think we could well do with a front page on the various routes to find your knot, the method depending on the different needs - want to know its name, a knot for a job, how to tie, other names, is it a new knot etc etc.
As far as the wiki is concerned, value only comes with 'critical mass' and the wiki today is well below any valuable 'critical mass', but if we keep plugging away at the resources, soon folks might start to find the resource useful and worth contributing to. As for the IGKT being the right responsible body to do this, I totally agree, and for the IGKT to retain any semblance of authoritative control, it would need to be through the guilds own wiki, rather than through wikipedia.
Derek
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Fair dos. I suppose it would all involve work - enough to put anyone off. I like the idea of 'empowering people to take action', but I suppose it would take a Guild Edict to really achieve the critical mass of which you speak. Perhaps when I am President, and you are all in my thrall, we shall see some action. Oh yes! Knotting on the National Curriculum; compulsory binding; reintroduction of village stocks, but using ecologically-sourced Constrictor knots instead of wooden contraptions; roving squads (with elegant, but robust, cats-o-nine-tails) of 'Grannies Against Grannies' checking that all shoelaces and neckties are appropriately arranged, bluetooth-linked to IGKT KnotSquad advisors... Just you wait til I am back on my feet!
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Hmmm,
Nope, not all people are put off by work - for example, there is at the moment a small team working to convert all the back issues of KM into pdf format so that everyone can access old out of print issues and can search this immensely valuable resource of Guild history.
As for edict -- well can you just imagine the response to Guild Edict No 1 :: All Guild members will with immediate effect make one contribution to the Guild Wiki every week :: The sort of person attracted to knotting might make some pretty interesting contributions to that edict. However, action is down to critical mass and that in many respects is an aspect of the Guilds drive to increase membership. The Guild is too small and unfortunately at the moment does not seem to be taking significant steps to increase those numbers. Perhaps when you are President you will come up with some good ideas on how to make membership of the Guild much more attractive to a wider section of the community, then some ideas on how to promote this new value to that potential membership base. Then again, perhaps you could turn your mind to that challenge now, while you wait for the next round of nominations.
Bringing back the Stocks and the Cat Oh YES YES and thrice times YES. And can I have prisons that are for PUNISHMENT and FREEDOM OF SPEECH and CORPORAL PUNISHMENT put back into schools at assembly, Oh and while I am at it, can I have a BOBBY back on the beat please. Now although you are probably suffering from an OD of morphine and Scotch, if you were to stand for those issues, then I would be your campaign manager, with or without thrall.
Derek
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Free Thinking, and a spirit of vigorous independence seem to go hand in hand with knotting, so perhaps - as you suggest - the Edict may not go down well. I certainly haven't the IT skills to rig up my dream list in any way that would allow others to safely contribute, so I shall leave it floating in the ether as another (one of many) opiated daydream.
As for the KM pdf project - Excellent news! I have been frustrated by one or two allusions to back issues on this site, so I look forward to dredging the archive when it becomes available.
As for those other touchy matters I stirred up in you... well, probably best (as with all the best clubs) to keep religion and politics off the agenda. I'm afraid I don't know what I am writing half the time!
I've made a nice dog lead, though - crown sennits, with a cunning bit of footrope to tie it around lampposts without losing the dog.
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Derek's enthusiasm to bring back the stocks, corporal punishment etc. ...
A lively, humerous debate took place in my local drinking establishment yesterday addressing such issues. I must confess that much of the debate was alcohol induced, so perhaps a clear headed contribution from Derek and Tom wouldn't go amiss?
We believe that our proposed "SOS" party might appeal to the law-abiding sections of society. "SOS" does suggest "help" after all, doesn't it? Unfortunately, at the moment, "SOS" stands for "Shoot on Sight"! For example, our proposed manifesto suggests the random placement of snipers at such terrible crime hot spots as places where inconsiderate drivers turn right at major junctions despite road signs demanding otherwise. Offenders would run the risk of being shot for such outrageous breaches of the law. OK, it may seem rather strict, but we figure once word got around people would stop doing it.
How does this relate to knotting, you may well ask? Well, there is the option of public flogging using the cat o' nine tails (is that decorative or practical, Derek?). The problem with flogging criminals, as opposed to shooting them, may be construed as "going soft on crime", so that is still under discussion.
"Three strikes and you're out" was also proposed. Let me explain - to err is human after all, and youngsters in particular might inadvertantly fall in with the wrong crowd. So, perhaps the first offence does not warrant being shot, the second offence is getting close, but three offences ... sorry, it's all over, matey! The first offence might be punished by a public flogging, and the "perp" could be paraded before the baying crowd with his hands tied behind his back with a simple handcuff knot, before being thrashed with the cat? Naturally, the criminal would be forced to construct his own cat o' nine tails, so teaching knots even to crooks is possible. See - knots and politics do mix!
Any suggestions for additions to the mainfesto gratefully received, especially if we can incorporate a knot or two!
By the way, how long do you think it takes to hang a condemned person? A story about Albert Pierrepoint, our most famous hangman ...
Albert entered the condemned cell, accompanied the condemned man through a door into his place of execution. Albert's accomplice tied the man's feet together, put a hood over his head and stood him over the trapdoor. Albert then pushed the lever (yes, pushed, not pulled) and the man dropped to his death.
How long did this process take, from entering the cell to the death of the condemned man? Read on ...
Pierrepoint's record was approximately 8, YES EIGHT, seconds!!!!!!
Phil
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I revisited this thread. I'm surprised, Derek, that you're so enthusiastic about the hitch in the original post. Over time, I've respected your input about other knots on this forum. However, I think the friction hitch in the original post is fundamentally flawed and inefficient for its purpose as a friction hitch. I wonder if you'd still be enthusiastic about the hitch in the original post after fully testing the Well Pipe (ABOK #504), the Klemheist (ABOK #1762), and the Xarax Grip Hitch (shown in link below).
http://igkt.net/sm/index.php?topic=1889.0
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I revisited this thread. I'm surprised, Derek, that you're so enthusiastic about the hitch in the original post. Over time, I've respected your input about other knots on this forum. However, I think the friction hitch in the original post is fundamentally flawed and inefficient for its purpose as a friction hitch. I wonder if you'd still be enthusiastic about the hitch in the original post after fully testing the Well Pipe (ABOK #504), the Klemheist (ABOK #1762), and the Gleipnir Grip Hitch (shown in link below).
http://igkt.net/sm/index.php?topic=1889.0
Hi knot4u,
To be honest, I was getting a bit concerned that others were getting fed up with me forever plugging the KC Hitch, so when topic 1889 came up I decided to give it a miss unless someone else mentioned the KC, so thanks for bringing it up for me.
I am interested in our reasoning that the KC is "fundamentally flawed and inefficient for its purpose" and would be most keen to hear our substantiation for our position. Having developed the hitch, I am obviously biased towards it, but equally, I am very keen to hear other opinions on its function and design.
As for the comparison of KC against "Well Pipe (ABOK #504), the Klemheist (ABOK #1762), and the Gleipnir Grip Hitch" - the situation with all these friction hitches is - as the name suggests - a matter of friction.
If the coefficient of friction is high then literally any old hitch will work - take a rusty old piece of pipe and a length of hempen cord, make two round turns and tie it off with a square knot and heave - it will work wonderfully.
The test then for a good friction hitch is when the coefficient of friction is particularly low.
I have tested the friction hitches using a piece of high gloss chrome tube and various cords. To date, in my tests ALL the classical friction hitches suffer from the same fundamental fault - they take a line from the input force right to the back of the knot and haul the whole of the knot forwards.
The KC was designed to apply the force at the front of the knot and leave the root or anchor of the knot to provide the fulcrum against which the opening coils develop leverage and hence magnify line tension - from increased tension comes increased contact pressure and so increase in the total frictional grip.
The test for my claims is in reality exceedingly simple. Choose a system with a challengingly low coefficient of friction - a glass bottle with say polyester braid, or if you are really brave, go for spectra braid. Tie a KC Hitch and the hitch of our choice back to back and then pull them apart - have the tension on the same side of the bottle in order to keep the tension in the worst possible orientation - directly in line.
Keep pulling til one of them starts to slide - then do it again, but this time turn the bottle round in case one end has an advantage over the other. The only rider is (and it was made quite clear in the introduction of the knot) there must be sufficient turns such that the last two turns do not start to open.
Try it for ourself and let me know what you find, but also, please let me know why you feel the hitch is 'fundamentally flawed'
Thanks
Derek
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Yes, I thought that a most provocative & unsupportable assertion,
myself --compounded by invoking the "Gleipnir pipe hitch" as anything
to be proud of! One can envision a simple sort of Tug-of-War test on
these. KC will take --indeed, nearly requires-- an initial yielding of
grip as it extends & tightens (so, too, Blake's/ProhGrip & Klemheist
--any coil-away structure, really),
but then it does tighten. As does the Icicle, another coil-away hitch.
And that Gleipnir structure in that circumstance should prove
especially ineffective at its own nipping!
;)
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Try it for ourself and let me know what you find, but also, please let me know why you feel the hitch is 'fundamentally flawed'
I think the KC Hitch is fundamentally flawed because the hitch must stretch out into relatively long ellipsoid coils in order for it to grip. If you don't see that as a flaw, then you may rest assured that the problem lies with me and not with the knot.
Yes, I thought that a most provocative & unsupportable assertion,
myself --compounded by invoking the "Gleipnir pipe hitch" as anything
to be proud of! One can envision a simple sort of Tug-of-War test on
these. KC will take --indeed, nearly requires-- an initial yielding of
grip as it extends & tightens (so, too, Blake's/ProhGrip & Klemheist
--any coil-away structure, really),
but then it does tighten. As does the Icicle, another coil-away hitch.
And that Gleipnir structure in that circumstance should prove
especially ineffective at its own nipping!
I guess it comes down to this: My testing has led me to different conclusions. However, we all may rest assured because I'm the one tying my knots, and you're the one tying your knots.
;)
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I think the KC Hitch is fundamentally flawed because the hitch must stretch out into relatively long ellipsoid coils in order for it to grip. If you don't see that as a flaw, then you may rest assured that the problem lies with me and not with the knot.
Or, rather, it might speak to the circumstances : in the large contrasting
sizes of object & line shown by Derek, it doesn't stretch out so much;
as those sizes become less different, the gripping is more a challenge
and it will stretch more. So, if not fundamentally "flawed," it is more
limited in practical application, then, perhaps.
So, the conditions (perhaps a variety) for the hitch-off Tug-o-War
yet need to be specified!
--dl*
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Hi K4u,
Thanks for the reply. I think we are moving forward, in that your reply suggests that you see the fundamental flaw as the need for the hitch to " stretch out into relatively long ellipsoid coils in order for it to grip".. Would I be correct in assuming that it is the amount of stretch that you see as the flaw? If my assumption is correct, then perhaps I have a basis to work from.
The definition of a knot that I choose to work with is that a knot is a Force Machine - physically simplistic, technically highly complex (it follows from this definition that cordage constructions that are not involved in force processing are either tangles or Decoratives , but that is the subject of another discussion). It goes without saying, that knots do not work by magic, they work with tensile and lateral forces, compressive forces and of course, putting it all to work - FRICTION. All cordage has a modulus of elasticity - some low, some surprisingly high, and as a tensile force is applied, the cords will stretch and slightly narrow under the applied load.
When a load is applied to a bend, the geometry of the knot applies the laterally generated forces to create internal grip of cord against cord.
When a load is applied to a hitch, the geometry of the knot applies the laterally generated forces to create grip against its 'host' object.
Paraphrasing that - load causes extension and creates force vectors, geometry creates tangential pressure and from this, friction with(against) the 'host' object.
Taking then the group of knots you have cited, essentially they all comprise a bunch of turns around the 'host'. None of them are drawn particularly tight (there is no 'Truckers Hitch' type elements in their make up), consequently they can all be relatively easily slid along the host.
So now we put them to work - in order for these round turns to grip, they need to develop tangential pressure in order to engage the coefficient of friction, and they all do it in the same manner - when a load is applied at right angles to the coils, they are subject to infinite leverage, so they move along the host in the direction of the load. If we are lucky one side moves while the opposite side stays put - this causes the cord turns to elongate into an ovoid shape and this stretching puts the cords under tension and the tension gives rise to the tangential pressure which builds the friction. The round turns continue to extend (become longer ovals) until the friction generated becomes great enough to hold the dragging force.
The problem with the coils opening, is that as the angle increases beyond 90 degrees, then the vector starts to express not only a compressive component at the back of the coils, but also it generates an increasing vector in line with the drag force. In low friction situations, this force is eventually great enough to force the back of the loops to slide forwards, and the moment this happens, the knot has failed.
This weakness is what the KC was designed to avoid. In the KC, there is no connection between the drag input and the back of the hitch. The only way a drag vector can reach the back of the hitch is if the friction is so low, that every turn is pulled open - then the KC will fail - this is why the stipulation is made that there should be sufficient turns that the last two do not open - these are the 'anchor' or 'root' of the hitch - if they have not been pulled open, then no slip force has reached the back of the hitch and the oval turns have generated all the necessary tension to create the required tangential force and hence frictional grip.
So now we have it - the fact that the first turn (or two or three... turns) have progressively opened is not a flaw at all - it is the reason why the KC has to hold while other hitches which are flawed by having the dragging force transmitted to every coil simultaneously will fail (in low friction situations).
Derek
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The problem with the coils opening, is that as the angle increases beyond 90 degrees, then the vector starts to express not only a compressive component at the back of the coils, but also it generates an increasing vector in line with the drag force. In low friction situations, this force is eventually great enough to force the back of the loops to slide forwards, and the moment this happens, the knot has failed.
This weakness is what the KC was designed to avoid. In the KC, there is no connection between the drag input and the back of the hitch. The only way a drag vector can reach the back of the hitch is if the friction is so low, that every turn is pulled open - then the KC will fail - this is why the stipulation is made that there should be sufficient turns that the last two do not open - these are the 'anchor' or 'root' of the hitch - if they have not been pulled open, then no slip force has reached the back of the hitch and the oval turns have generated all the necessary tension to create the required tangential force and hence frictional grip.
So now we have it - the fact that the first turn (or two or three... turns) have progressively opened is not a flaw at all - it is the reason why the KC has to hold while other hitches which are flawed by having the dragging force transmitted to every coil simultaneously will fail (in low friction situations).
Derek
The weakness you mentioned is theoretical. If I make the stipulation (like you did) that at least the top two coil remain together, then the hitches I mentioned have not failed on me. Also, let's compare apples to apples. The KC Hitch in the original post would need to be compared to a Well Pipe Hitch (ABOK #504) having 8 coils because that's how many coils your KC Hitch has. If you manage to slip a Well Pipe Hitch having 8 coils tightly dressed, then please share the parameters you used before we get caught up in too much theory here. At least try that hitch out before you further explain this theoretical weakness. I just got done testing that hitch on a slick vertical pole. It's a robust diesel.
For reference, here are the hitches I'm comparing to the KC Hitch:
http://igkt.net/sm/index.php?topic=1889.0
However, let's back up. The fundamental operation of the KC Hitch is vastly different than the hitches I mentioned. It's awkward comparing fine details of the knots because, before we get to the details, the fundamentals are so hugely different. The KC Hitch and the hitches I mentioned can co-exist because they each excel in different categories.
In the hitches I mentioned, a feature (probably the strongest feature) is that the tangential forces against the pole increase proportionally as the load increases. Accordingly, if the hitch holds with a mild load, it's a fair assumption that the hitch will hold with a heavier load (given the hitch undergoes little more deformation).
In contrast, the KC Hitch is a bit more complex with how the force against the pole increases. The KC Hitch relies on its elongation AND overlaps to increase the pressure against the pole. The top of the hitch must initially be fairly tight, AND the top of the hitch only increases in tightness as the forces work their way up through the coils and overlaps to make the top of the KC Hitch tight. In fact, the KC Hitch does not even rely much on the top coils. That feature may be preferable on a cone-shaped pole where the standing end is pulled in the direction of the narrow part of the pole. (Just guessing, I have not tested this application.)
A weakness of the KC hitch is the overlaps, which ironically are necessary for the KC Hitch to work. Note that you have displayed relatively thin rope on a relatively thick pole. I contend that's the ideal and only recommended use for the KC Hitch. In contrast, if we have relatively THICK rope on a relatively THIN pole, then suddenly the overlaps compromise security, but again the overlaps are necessary. What are the relative rope dimensions at which we no longer recommend the KC Hitch? Take your guess, and make sure the person is not asking you about a critical application. Note, this issue is less of a concern (or non-existent) with a Well Pipe Hitch.
To recap, the KC Hitch and the hitches I mentioned can co-exist because they each excel in different categories. I might prefer the KC Hitch on a cone-shaped pole where the standing end is pulled in the direction of the narrow part of the pole. (Just guessing, I have not tested this application.) I would prefer the other hitches I mentioned for most (or all) other applications.
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For reference, here are the hitches I'm comparing to the KC Hitch:
http://igkt.net/sm/index.php?topic=1889.0
WOW, for a guy giving so much voice to locking threads,
going back to edit in a new knot-image into the OP of a June
2010 thread in 2011 wins a prize!? Good way to make the
replies look like they're missing part of the post.
I might prefer the KC Hitch on a cone-shaped pole where the standing end is pulled in the direction of the narrow part of the pole. (Just guessing, I have not tested this application.) I would prefer the other hitches I mentioned for most (or all) other applications.
I don't know, it seems that with each extension degree KC is
surrounding a diminishing diameter and so would need to
extend farther and ... --not a good case for it. (I don't know
of anything with a much of a taper on it to test --shovel handle's
taper is slight.)
--dl*
====
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For reference, here are the hitches I'm comparing to the KC Hitch:
http://igkt.net/sm/index.php?topic=1889.0
WOW, for a guy giving so much voice to locking threads,
going back to edit in a new knot-image into the OP of a June
2010 thread in 2011 wins a prize!? Good way to make the
replies look like they're missing part of the post.
Yes, that's lame on my part. Further, I gutted over 10 posts from that thread. The thread is now mangled. The good news is you only need my original post. :)