Author Topic: Multiple independent fixed loops, tied around a post  (Read 3881 times)

staunchmop

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Multiple independent fixed loops, tied around a post
« on: October 19, 2012, 03:48:44 AM »
Hello,

I'm looking for a knot with multiple, independent fixed loops, all of which are tied around a post. The real goal here is to distribute the weight evenly among many loops. This is similar to the bowline on the bight. However, as far as I know, that knot cannot be tied around a post. It can be tied in hand, slipped on, and tightened, but that is less convenient. Is there a knot like the one I'm looking for?

I've tried the Portuguese bowline, but it seems that the loops cannot be used independently without slipping. Thanks!

roo

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Re: Multiple independent fixed loops, tied around a post
« Reply #1 on: October 19, 2012, 05:45:04 AM »
Hello,

I'm looking for a knot with multiple, independent fixed loops, all of which are tied around a post. The real goal here is to distribute the weight evenly among many loops. This is similar to the bowline on the bight. However, as far as I know, that knot cannot be tied around a post. It can be tied in hand, slipped on, and tightened, but that is less convenient. Is there a knot like the one I'm looking for?

I've tried the Portuguese bowline, but it seems that the loops cannot be used independently without slipping. Thanks!
Your description is hard to decipher.  Maybe if you describe your application, it might clear things up.  I'm not sure what you're trying to communicate with the "tied around a post" description.
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X1

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Re: Multiple independent fixed loops, tied around a post
« Reply #2 on: October 19, 2012, 09:30:44 AM »
...multiple, independent fixed loops
The real goal here is to distribute the weight evenly among many loops.

  Those two purposes are mutually exclusive. If the loops are independent ( i.e., do not "communicate" with each other ), they will not distribute the weight evenly- and to be capable to distribute the weight evenly, they should not be independent.
  The only way I can see something working like what you are searching for, is a compound knot, a rope-made pulley mechanism: Imagine, say, 4 fixed loops that are tied around a post in a raw, so that the tail of the one loop forms a bight, and becomes the standing end of the other loop. Then, connect the first and the third bight together in a pair, with a fourth bight, and attach the standing end of the compound knot to this fourth bight !  :)  The 4 end loops would be independent, yet the weight would be evenly distributed within them ( 1/4 on each loop ). You do not want to draw an inverted Christmas tree with rope, do you ?  :)
   Try the Double Cow hitch presented at (1), (2). The 4 loops are not independent, but I believe they distribute the weight in a satisfactory way.

1.   http://igkt.net/sm/index.php?topic=4035.0
2.   http://igkt.net/sm/index.php?topic=4035.msg24395#msg24395
« Last Edit: October 19, 2012, 10:16:23 AM by X1 »

Sweeney

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Re: Multiple independent fixed loops, tied around a post
« Reply #3 on: October 19, 2012, 04:37:18 PM »
This is similar to the bowline on the bight. However, as far as I know, that knot cannot be tied around a post.
I agree with X1 - trying to get two fixed loops of exactly the same size is at best difficult. However the bowline on the bight can easily be tied around a post if you really want to use it. Simply tie an ordinary bowline and leave a longer than usual working end. Now follow the knot round starting with the loop and you will have a bowline on the bight (used by some climbers as a tie in to a harness so cannot be tied in hand first).

Personally I would look at the tensionless hitch as an easy means of distributing the strain - there are several Youtube videos on this and most show a carabiner to complete the hitch though with enough wraps a knot around the standing part works as well. It all depends on what you're trying to do as Roo said earlier.

Barry

Dan_Lehman

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Re: Multiple independent fixed loops, tied around a post
« Reply #4 on: October 19, 2012, 07:26:38 PM »
This is similar to the bowline on the bight. However, as far as I know, that knot cannot be tied around a post.
I agree with X1 - trying to get two fixed loops of exactly the same size is at best difficult.

I concur in X1's judgement (and Roo's uncertainty) that the
two expressed goals are at odds with each other.  I'll go further
and say that distribution of forces is unlikely to occur by any
slippage of cordage, which has too much friction to be much
at all equitable --it can slip, but not to the point of near equalizing!
And, if one is tying multiple loops (eyes) around a pole,
how are they to then be independently used?

So, some further insight into your needs will be appreciated.

Quote
However the bowline on the bight can easily be tied around a post
if you really want to use it.

Indeed, it is argued to be one of the better ways for
rockclimbers to tie into the climbing rope --though, to my
mind, it's not optimal in that (i.e., there should be another
way to finish the knot, given one twin part being destined
as the tail).

Quote
Personally I would look at the tensionless hitch as an easy means
of distributing the strain
:o
I fail to see how this at all distributes strain:
100% tension comes into contact with the object
via the SPart which is a single strand (in contrast,
say, to the two legs of an eye knot),
and the extent of wrapping of that strand provides
more material to extend/stretch under load, so more
frictional rubbing (etching!) against the object.
(There seems to be this common misconception of the t.h. .)

--dl*
====

staunchmop

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Re: Multiple independent fixed loops, tied around a post
« Reply #5 on: October 21, 2012, 05:50:41 PM »
I'm not sure how helpful the application is, since it's a sort of proof-of-concept construction I'm working on with friends. I'm trying to maximize the weight hanging from a pole made from a soft material. Too much weight supported by one loop will actually bite straight through the material. Thus, the multiple loops. Also, obviously, I don't want the knot to draw up against the material, because then the rope is exerting its own force. So the loops have to be fixed).

I suppose it's not important that they're independent, though, after all. I was a little worried that if the weight were subject to other forces and it swung around, one loop would pull some of the slack from the others and bite into the material. But that probably won't happen I suppose.

Also, the pole is fixed on either side to larger objects, so it's hard to slip something on to it. It is possible to slip the rope around one of the objects, but obviously not optimal!

Thanks for the help so far! I will try that method of tying the bowline on the bight, thank you! However, I think the double cow hitch and tensionless hitch will probably draw up too much.
« Last Edit: October 21, 2012, 05:52:51 PM by staunchmop »

Luca

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Re: Multiple independent fixed loops, tied around a post
« Reply #6 on: October 21, 2012, 07:27:50 PM »
Hi staunchmop,

If you continue to be interested in the realization of a knot with multiple fixed loops , without being tied on the bight, around a single pole, as you specify now, the Birmingham bowline could be a solution: it should be quite easy to adjust the loops in so that they have roughly the same length and that then is distributed fairly well the weight, also should be fairly intuitive realize two or more loops using this knot:

http://daveroot.netau.net/Knots/Knots_DoubleLoops.htm#BirminghamBowline

Another solution could be this:

http://daveroot.netau.net/Knots/Knots_DoubleLoops.htm#DoubleDoubleDragon (Method # 2)

Maybe safer (I think), but more difficult to realize, I believe, and I think it's even more difficult to adjust the length of the loops;the single loop version is here:

http://daveroot.netau.net/Knots/Knots_SingleLoops.htm#DoubleDragon (Method # 2)

                                                                                                            Bye!
« Last Edit: February 03, 2013, 01:51:28 AM by Luca »

roo

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Re: Multiple independent fixed loops, tied around a post
« Reply #7 on: October 22, 2012, 12:09:19 AM »
I'm not sure how helpful the application is, since it's a sort of proof-of-concept construction I'm working on with friends. I'm trying to maximize the weight hanging from a pole made from a soft material. Too much weight supported by one loop will actually bite straight through the material. Thus, the multiple loops. Also, obviously, I don't want the knot to draw up against the material, because then the rope is exerting its own force. So the loops have to be fixed).
I see.  You're looking for a self-equalizing system.  This can be done easily with only two standard knots:

First, you tie a Butterfly Loop or Span Loop a reasonable distance from the pole or bar.  Then, run the free end of the rope around the bar, then back though the Butterfly Loop, the back around the bar, then back through the Butterfly Loop, and back around the bar (etc., as needed) and then finish by attaching a Bowline (or some end loop) to the Butterfly Loop.

« Last Edit: October 22, 2012, 12:12:21 AM by roo »
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