Author Topic: Good knots for tying the middle of a rope to an "endless bar"?  (Read 15510 times)

Gordias

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Good knots for tying the middle of a rope to an "endless bar"?
« on: November 12, 2014, 06:06:27 PM »
 I've seen a "round turn and two half hitches" with the rope doubled (i.e. tied using a bight) used to tie small boats to trees, and I discovered the "Midspan Sheet Bend" today:
http://notableknotindex.webs.com/midspan.html

Assuming it holds well enough, the RTTHH has the usual advantage that it can be used when the rope is under (moderate) tension, but I've never seen one tied this way subjected to significant strain (where I go boating there are no tides, and our wakes are larger than our waves :)

The midspan sheet bend handled about 20 kg easily (my leaning on the rope), but I have no way to test it under a significant load.

I won't be applying more than say 50 kg to either one (and probably a lot less), but even if those two knots would work well for me, I'm interested in the other options.

Are those two good knots for this purpose? Are there other good knots for it?  Any special ones for unusual conditions?

roo

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #1 on: November 12, 2014, 06:41:12 PM »
I've seen a "round turn and two half hitches" with the rope doubled (i.e. tied using a bight) used to tie small boats to trees, and I discovered the "Midspan Sheet Bend" today:
http://notableknotindex.webs.com/midspan.html

Assuming it holds well enough, the RTTHH has the usual advantage that it can be used when the rope is under (moderate) tension, but I've never seen one tied this way subjected to significant strain (where I go boating there are no tides, and our wakes are larger than our waves :)

The midspan sheet bend handled about 20 kg easily (my leaning on the rope), but I have no way to test it under a significant load.

I won't be applying more than say 50 kg to either one (and probably a lot less), but even if those two knots would work well for me, I'm interested in the other options.

Are those two good knots for this purpose? Are there other good knots for it?  Any special ones for unusual conditions?
Another simple one is a Timber Hitch on the Bight:

http://notableknotindex.webs.com/timberhitch.html (second diagram)

All three would probably work, but the round turn and two half hitches tied on the bight would likely be the least secure of the lot.

If only one end of the rope will be loaded you can also investigate the Tumble Hitch, the Tumbling Timber Hitch and the Halter Hitch (tied with an on-the-bight method):

http://notableknotindex.webs.com/tumblehitch.html
http://notableknotindex.webs.com/timberhitch.html (third diagram)
http://notableknotindex.webs.com/haltersiberian.html (third diagram)
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xarax

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #2 on: November 12, 2014, 09:40:33 PM »
  You have not indicated if the pull is supposed to be a right-angle or a lengthwise one...
  Unless you are prepared to tie such a bad and ugly knot as the "Timber hitch on the bight" ( I do not even "click" on the other "offered' ( = advertised...) "solutions" of the previous post, because, in general, we should not buy any low-quality things, however "cheap" they are, the various traveling salesmen try to sell to us...), you have a real problem : I do not believe there are any simple and secure knots, which, without consuming half of your available rope length, will do this particular job. The same applies for the TIB-to-TIB ( midline-to-midline ) bends : Knots are not a panacea for each and every rope-fastening problem.
   Two possible less bad and ugly ( but still not "good" ) solutions, are shown in the attached pictures. I would be glad if somebody would figure out something more decent... The only other thing we can do is to just tie any of the very simple hitch we have in-the-bight, and with-a-bight. Try a double-line "Simplest hitch", shown in the third picture, which is the simplest one-wrap hitch around a pole - within a ring or a bight, try a double-line "Blackwall hitch" .
« Last Edit: November 12, 2014, 09:41:54 PM by xarax »
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Gordias

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #3 on: November 13, 2014, 12:22:59 PM »
Thanks for the answers so far.

To clarify the direction of pull:
The "entry point" for my question was tying a small boat to a tree for relatively short periods, but as soon as I started thinking about it I realized there are  many situations when you want to make mid-rope loops around "endless bars and/or rings permanently attached to something large so I tried to make a general question.

So the short answer: I should have said the tension will always be at right angles to the "bar".

I've never actually tied a hitch for pulling lengthwise on something like a spar or a tree, but I've seen it done a few times:  many times (over a relatively short interval) to pull railway sleepers out from under a building with a truck, and a few times to pull small logs.  After your posts I'm interested in this situation as well, so I'll try to learn both the standard hitches and your examples for longitudinal tension.

Back to the perpendicular tension case:
 * I'm not too surprised the RTTHH using a bight isn't necessarily reliable, but what about the midline sheet bend?

* I expected to learn that there's a bowline variant I could use in this case.  I tried out bowlines using a doubled rope as an experiment today:  the standard bowline and water bowlines are easy enough to tie.  The Monsoon is definitely more of a hassle than normal, but it seemed ok after I was done.  Much more interesting though:  will any of them perform adequately given the inevitable unbalanced stresses inside the knot?  I doubt it's possible to spread tension evenly across both sides of the doubled knot - I certainly didn't manage with the ones I tied today.

PS:
I do have a simple solution if there are no really good knots for this:  If I have a rope with me I always old climbing carabiners and S-carabiners with me, so I can tie a couple of butterfies and link them around the tree with a carabiner.  This isn't so good in every imaginable case though - I wouldn't want a carabiner in contact with a smallish-diameter cylinder because there would be forces coming in directions they not designed for (especially the gate, which could be damaged by enough force applied at right angles to its length).
« Last Edit: November 13, 2014, 03:37:21 PM by Gordias »

xarax

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #4 on: November 13, 2014, 02:52:03 PM »
  I tried to make a general question.

  This is very good. Keep asking general questions !  :) Only answers to general questions are interesting - because they are the only ones which can generate even more questions, and even more answers, and so on - which is what we seek. The journey itself is the task, not the destination. Knotting but the verb ( knotting ), knot the particular object ( particular knot ).

  Right-angle pull, not-"tight' hitches and nooses are the easiest knots : there are dozens of dozens of them, and most of them will do the job perfectly. However, to tie any of them with-a-bight, i.e. with the line doubled, is what somebody would be right to describe as "half clever". Multiply the amount of material by two, for the same purpose = divide the efficiency by two. And there is no way to neatly solve this problems with the "unbalanced stresses inside the knot" you mention.

   The so-called "Midspan sheet bend" is a mediocre knot, which is not TIB in this sense / case: To encircle the "endless bar", you have to pass one end of the rope behind it - otherwise you should use a bight formed in the rope, and then encircle the "endless bar" with this bight, which is equivalent of tying a knot in-the-bight, and with-a-bight. I thought you had asked for a TIB solution, i.e. a solution which can be applied without any access to any of the two ends of the rope ( as the solutions I had shown ). If you do have access to the one end of the rope, you do not have any problem !  :)  :) There are hundreds of hitches and nooses out there - and I have to point out that few are less clever than the so-called "Mons00n bowline" !  :)   
   To be more "practical", I would answer that the knot you seek depends on the age of the tree !  :)  Around an "endless bar" of a small diameter, a double line hitch or noose would make sense, indeed. If the diameter is large, you should keep seeking - or do what I do : Use a second rope, permanently tied around the trunk of the tree, and attach your line on this, with any double-line one-wrap hitch or noose you wish. If you can not find a knot for one rope, use a second rope:)

P.S. Some bight-to-bight bends / solutions, are shown at :
       http://igkt.net/sm/index.php?topic=3640.0
« Last Edit: November 13, 2014, 02:56:57 PM by xarax »
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roo

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #5 on: November 13, 2014, 04:19:17 PM »
To clarify the direction of pull:
The "entry point" for my question was tying a small boat to a tree for relatively short periods, but as soon as I started thinking about it I realized there are  many situations when you want to make mid-rope loops around "endless bars and/or rings permanently attached to something large so I tried to make a general question.

If you're tying around a large object like a tree, then I'd definitely recommend the Midspan Sheet Bend to pinch off a loop.  It'll  use much less rope than most other options and will take the forces just fine.
« Last Edit: November 13, 2014, 04:26:41 PM by roo »
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Dan_Lehman

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #6 on: November 13, 2014, 08:46:13 PM »
I've seen a "round turn and two half hitches" with the rope doubled (i.e. tied using a bight) used to tie small boats to trees, and I discovered the "Midspan Sheet Bend" today:
http://notableknotindex.webs.com/midspan.html

Assuming it holds well enough, the RTTHH has the usual advantage that it can be used when the rope is under (moderate) tension, but I've never seen one tied this way subjected to significant strain (where I go boating there are no tides, and our wakes are larger than our waves :)

One might ask : Why do you need to tie without ends
--how long is this line on the small boat (part of whose
regular activity one might presume to be being tied up,
mooring!) ?  Does one transport all of this extra line
out of the boat to sit beside the tree, or does it extend
also back into the boat, but simply be unsecured there?

You write "RTTHH" and we should remark that that entails
a full wrap with doubled rope per your presented situation
--why the full wrap, around a tree?!  (Well, you do say "small
tree", so less of an expense of cordage in wrapping that.)

For simplicity and other reasons, I'd simply take the wrap
(full/"round turn" or half/mere "turn") around the tree
and tie off with 2 half-hitches, possibly essentially
using one strand (that connecting directly to the S.Part)
and letting the twin follow idly away from my working,
until the closing half-hitch; then, I'd slip-knot the main
strand snug to this HH to prevent loosening.


--dl*
====

xarax

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #7 on: November 14, 2014, 12:41:51 AM »
   Trying to "save" you from the Mons00n pneumonia and the "abbreviated" double-line RTTHH headache,  :) ( definitely a not-so-clever knot in this case, to say the least...),  I remembered a not-so-well-known, but very simple, conceptually, bowline, which utilizes the stiffness of the rope, i.e., a slipped bight on the Tail End ( = the end which is not tensioned ) as a toggle. See the attached picture, for the simplest such solution. Depending on the load, you may decide to drive the double-line Tail End through a more convoluted path, as shown in :
    http://igkt.net/sm/index.php?topic=4712.0
    http://igkt.net/sm/index.php?topic=3924
    http://igkt.net/sm/index.php?topic=3924.msg23299#msg23299
« Last Edit: November 14, 2014, 02:30:03 AM by xarax »
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Dan_Lehman

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #8 on: November 14, 2014, 07:56:15 PM »
To clarify the direction of pull:
The "entry point" for my question was tying a small boat to a tree for relatively short periods, but as soon as I started thinking about it I realized there are  many situations when you want to make mid-rope loops around "endless bars and/or rings permanently attached to something large so I tried to make a general question.

If you're tying around a large object like a tree, then I'd definitely recommend the Midspan Sheet Bend to pinch off a loop.  It'll  use much less rope than most other options and will take the forces just fine.

How so ((much) less rope)?!
If you posit your image of that structure,
then you have single strands --no doubling--
all 'round; but consider the situation of tying
to a tree in the bight --i.e., presumably, one
cannot bring the end of the line around the tree
in this case, but must work from the middle.
(While one can go around to the back side
of the tree and make a MLSBend, there will
be doubling of the line on both sides,
returning to the boat.)

--dl*
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roo

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #9 on: November 14, 2014, 08:30:28 PM »
To clarify the direction of pull:
The "entry point" for my question was tying a small boat to a tree for relatively short periods, but as soon as I started thinking about it I realized there are  many situations when you want to make mid-rope loops around "endless bars and/or rings permanently attached to something large so I tried to make a general question.

If you're tying around a large object like a tree, then I'd definitely recommend the Midspan Sheet Bend to pinch off a loop.  It'll  use much less rope than most other options and will take the forces just fine.

How so ((much) less rope)?!
If you posit your image of that structure,
then you have single strands --no doubling--
all 'round; but consider the situation of tying
to a tree in the bight --i.e., presumably, one
cannot bring the end of the line around the tree
in this case, but must work from the middle.
(While one can go around to the back side
of the tree and make a MLSBend, there will
be doubling of the line on both sides,
returning to the boat.)

--dl*
====

For example, a Tumble Hitch or a Timber Hitch on the Bight (or any other fully doubled/twinned hitch) will use a lot more rope around a large object due to the number of passes around the object.  That covers "most other options".

The difference will be less for options such as your two half hitches doubled on the working end, but not the standing part.  However, the Midspan Sheet Bend will still use less rope (at the knot body), will be cleaner in appearance, and is designed to take load from either of the lines leading to the tree.

P.S.  If he wanted to have one line release the hitch, the following two hitches (also mentioned above) will not use too much rope on a large object:

http://notableknotindex.webs.com/timberhitch.html (Tumbling Timber Hitch, third diagram)
http://notableknotindex.webs.com/haltersiberian.html (third diagram)
« Last Edit: November 15, 2014, 12:17:22 AM by roo »
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xarax

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More about the so-called "Midspan Sheet bend"...
« Reply #10 on: November 16, 2014, 08:48:37 PM »
   ...which is nothing more than a double-line Sheet bend, of course - and it can only be loaded in the particular way the Sheet bend is loaded : i.e., the ends should be parallel to the axis of the knot, not perpendicular to it ( as advertised... :) ). Otherwise, the two legs of the Sheet bend will split / spread... no knot tyer or not would wish to watch this !  :) I copy and paste a relevant post (0) :

   " If I had to point out the less clever ( = most dumb ) knots I know, this so-called "Midspan Sheet bend" would probably be the first.[ Edited : among the firsts - I should not forget the Shepherd s hitch :), not to mention the double line Timber hitch, advertised as : "Timber hitch on the bight" ). And I am really sad that the knot tying community has been parroting this ugly tangly over and over again, all those years !  We have taken a double line Sheet bend ( you know, the ABoK # 1 ! ) and we are proud that we have managed to reduce just a tiny fraction of the required material... A great achievement, indeed ! Then, we try to conceal the fact that this tangle is working like a proper Sheet bend only in a few of all the possible orientations and loading patters of the two lines. In particular, when the two lines are parallel to each other, and both ends of the one, at least, line are loaded, this ugly tangy reveals its true monstrous face ! However, in the web sites where the beast is presented / advertised as a beauty, one will not see even one picture of a loaded knot : perhaps because it would have been difficult for us, the lesser knot tyers, to follow the segments of the ropes, the owners of the sites are kind enough to present only sketches of "exploded", loose knots... :)   
   As a bight-to-bight bend, the "Midspan Sheet bend" behaves as a proper Sheet bend, indeed - and this is the only case when it deserves this name. In this particular role, and in this role only, it is quite satisfactory, and I believe that a more complex bend, like the ones presented in (1), would seldom be needed and required. 
   However, when each of the two bights is formed on each of two parallel lines, the ex-Sheet bend will hold only if it is lucky enough to squeeze every last tiny fraction of friction generated within its deformed, ugly body. The tensile forces which should help the bights to close and embrace each other, work in the exact opposite, destructive way : they tend to open them up, and to tear them apart. Especially the poor bight with the uncrossed legs, is suffering a lot in this spagato [ = splits : (2)] it is forced to perform, and only a miraculously balanced distribution of tensile forces would alleviate its pain - but there are no miracles taking place in real life recently, I am afraid. One would expect the utilization of one or more nipping loops, to squeeze a double line going through them, so the loading of the lines would become beneficial, and not catastrophic, for the connection. When one has the Gleipnir, the Bowline, the Sheepshank, the Captain Mullin s knot, all those knots that utilize / take advantage of the loading of the ends, he can not be satisfied with this tangle which suffers from it. 
    The problem is : What can we do ? There are things we simply are not able to do with knots, and we will never be. The variety of possible rope-made mechanisms is condemned to be limited, if the allowed complexity of them is also limited. Will we ever fly using a simple knot ? I doubt it !  :)  Now, should we use an ugly tangly, when we have not anything else ? That is a matter of personal taste. Personally, I will not. I respect knots, and I do not like to see them suffering, trying to do things they simply can not do, given the limits of complexity allowed to them. I would better chose another method, or tie a much more complex knot, but I will not use an ugly tangly that "would simply do the job" - provided the loading will not be heavy, and we will keep our fingers crossed !   
   Simplicity is a great thing, but it should not be used as an excuse, in situations it simply does not apply ! I myself do not know any simple TIB knot that would hold two lines together, independently of the loading pattern of the four limbs. This "Midspan Sheet bend" is a decent bight-to-bight bend, and nothing more. Its name is deceiving, and has mislead people to believe that it is the miraculous simple medicine that cures all diseases... It does not. Instead of trying to figure out the few applications where this knot will work, (simply because any tangle can work, if it is loaded in a particular way and with light enough loads...), I suggest we try to find something better, even if this will require a much more complex knot. Parroting will continue, that is for sure, because it is such a successful strategy of nature. However, imagination and creativity should continue, too. And if it is proved that there is nothing else satisfactory enough, there will be always the option of a line-to-line mechanical fastener !  :) "

0. http://igkt.net/sm/index.php?topic=4432.msg28042#msg28042
1. http://igkt.net/sm/index.php?topic=3640.0
2. http://en.wikipedia.org/wiki/Split_(gymnastics)
« Last Edit: November 16, 2014, 08:52:43 PM by xarax »
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Knutern

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #11 on: November 27, 2014, 01:19:38 AM »
Hi.

I beleive the Bull Clove hitch (TIB method) could be used. However, trying tying this myself I wasn't able to get it dressed properly - the clove part gets twisted the wrong way  ???
I'm aiming for knots that is secure, AND that is easy to untie.

Luca

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #12 on: November 27, 2014, 06:31:08 AM »
Hi Knutern,

If the bar is endless,it is impossible to tie the Clove-Bull hitch,at least just as it is( http://igkt.net/sm/index.php?topic=4748.msg30673#msg30673 ),using any TIB method.
If the bar(planted in any place on the surface of the planet Earth) is no endless as the planet Earth is no endless, using the "Girth+Bull hitch way method"( http://igkt.net/sm/index.php?topic=4748.msg33175#msg33175 ),(a TIB method suitable to build the hitch in the bight DIRECTLY through a ring,or DIRECTLY around a bar*if both the ends(of the bar)are accessible),is theoretically possible,...but one has to pass the entire bar and the entire planet Earth through,during the stages of the realization of the knot!(and is not pratically suitable any other TIB method even in this case,if the opened end of the bar is not accessible)

*Using the other TIB methods proposed in the thread linked above,is not possible to build the hitch directly through a ring, or directly around an "opened" handle(nor with one nor with two ends accessible), but one can only build the hitch "on the air",and only after,apply the hitch to an "opened handle"(and not to a ring( or "topologically" a ring,ie for example a ring with a dude attached!( https://www.youtube.com/watch?v=PzIP4IUnqvI )). 

                                                                                                                                    Bye!
« Last Edit: November 27, 2014, 10:03:57 AM by Luca »

Dan_Lehman

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #13 on: November 27, 2014, 06:49:50 PM »
An anchor hitch noose can also work in the case
of tying the bight to a ring (or larger), giving
wraps to resist opening up if the two noose's
SParts are loaded in different directions
--orient the a.h. such that its tail points
away from the object.

We're still waiting for an answer to my question about
the practical need for this tying off of a boat with
such a knotted structure --seems odd, IMO.


--dl*
====

Knutern

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Re: Good knots for tying the middle of a rope to an "endless bar"?
« Reply #14 on: November 28, 2014, 05:47:53 PM »
Sorry, I didn't remember both rope and bar was endeless :(
I'm aiming for knots that is secure, AND that is easy to untie.