Author Topic: Best lashing knot for three perpendicular poles.  (Read 25178 times)

DDK

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Re: Best lashing knot for three perpendicular poles.
« Reply #15 on: October 31, 2010, 11:24:05 PM »
...Apply the round turns but not the fraps to 3 parallel poles.
...The poles can be ...stationary prior to their binding.

   So you are telling me that the application of the round turns is not part of the binding process, and the subsequent rotation of the poles - from the parallel to the orthogonal position- does not mean that the poles are not stationary at the phase of their binding, because "binding" refers only to the application of the fraps, not the application of the round turns or the rotation of the poles ?  :)
   Instead of defending this far fetched view, we could better try to improve the "Japanese scaffold lashing" and adapt it in the case of the 3 perpendicular poles, and see what happens.

My mistake - I thought the term reverse-engineering was fairly common and would be understood.  It describes a process by which one may develop understanding and/or a new process from an existing process, for example.   In this case, once one has easily discerned how the round turns are to be wrapped on stationary and orthogonal poles by spreading the tripod in the conventionally wrapped lashing of parallel poles, one forever knows how to apply the round turns from scratch to any set of stationary and orthogonal poles. So, in this "newly" developed process with this "new" information, the poles are in contact, orthogonal and stationary prior to the wrapping of any round turns or fraps.  There is nothing at all farfetched about it.  

DDK

« Last Edit: October 31, 2010, 11:25:18 PM by DDK »

SS369

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Re: Best lashing knot for three perpendicular poles.
« Reply #16 on: November 01, 2010, 01:51:26 AM »
I have been experimenting with this one a bit and besides the want of the poles to go everywhere except where I need them here's the best method I've come up with to date.


However you can secure the three perpendicular poles in the correct orientation, do so.

Cut a suitable piece of accordingly sized cord/rope to length.

Starting with the "vertical" pole tie a double constrictor knot at location and tighten with the leads going around to the backside of the knot. Cross the leads back there. That should be the outside of the corner.
I originally tried Prusik, clove and Klemheist hitches and they work, just not as well.

Now position the additional poles to their respective perpendicular places above the dbl constrictor.

Take the two now crossed leads and go around the outside of the two crossed and touching poles guiding one cord into the each "V". Now do one or two frappings around the V's with both lines in opposite directions. This is all happening outside the vertical pole.

Finally take the leads under both horizontal poles and cross them while going up inside to the final position of over and outside the horizontal poles to be tied off with any number of binding knots. Though continuing to go around the unoccupied V (back) and then to tie off around the vertical pole will add some more spreading stability. to the whole thing.

The main thing is to have a dependable support knot on the main pole and then frapping turns that will cinch the two other poles snug to the main.
Looks like hell but it will freely hold the three poles.

Hope it makes sense. I see it so...... muddily.
:-)



SS369

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Re: Best lashing knot for three perpendicular poles.
« Reply #17 on: November 01, 2010, 02:20:20 PM »
Oh yes, I agree wholeheartedly that the affair I have tangled lacks symmetry.
The first thought was to get the job done.
Next it was to minimize the amount of cord used without diminishing security.
Third is relative ease of tying. Which I don't think I did either.

I believe the basic concept-design elements of what I did would be enhanced by additional round turns on each of the members and even then around all of them.
But that will use an awful amount of cord.
As for a "knot" doing this and doing it well, I think not.

Maybe you could do some kind of super duper go everywhere Pile hitch twisting,and yanking as she went.

What have you got?

Dan_Lehman

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Re: Best lashing knot for three perpendicular poles.
« Reply #18 on: November 04, 2010, 05:51:33 PM »
Have you considered the Chinese bamboo scaffold solution?

A nice picture for the "Knots in the Wild" thread, perhaps.  :)
I have also considered Mongolian yurts, but they are circular structures, no relation to western Cartesianism there too, I am affraid.. :)

???
If this photo does not show the general relationships of the
"Bind three poles, in touch and perpendicular to one other"
problem you're exploring, please explain why not, and what does.

To me, an essential element of reality is missing from the problem
statement --to wit, gravity : what bears load, in what direction!?
E.g., in Derek's presented image, the vertical pole supports the
others bound to it, and one might bind the lower of these very
securely essentially just *attach* the 3rd one stop this support,
or one might bind the upper and essentially support the lower
via friction-hitch mechanics.

--dl*
====

Tha

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Re: Best lashing knot for three perpendicular poles.
« Reply #19 on: November 16, 2010, 09:03:19 AM »
Hi, I just joined the forum and made my first post. By coincidence it is a solution to the problem posted in this thread. Xarax pointed this out. See http://igkt.net/sm/index.php?topic=2078.0

DerekSmith

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Re: Best lashing knot for three perpendicular poles.
« Reply #20 on: November 19, 2010, 12:43:03 AM »
Lovely symmetry, but virtually zero ability to transfer vertical force on the horizontal poles into the vertical pole (or any other combination), and no mechanism to leverage cord tension.

Was your challenge intended to be functional or simply decorative?

Derek

squarerigger

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Re: Best lashing knot for three perpendicular poles.
« Reply #21 on: November 19, 2010, 08:35:13 PM »
Just a thought or perhaps a question:

If you have three poles of circular cross-section at an x,y,z locus, then perhaps the joining material/fiber should be ribbon-like in cross-section to obtain the greatest frictive resistance?  It could be a flat ribbon (woven) or a sennit covered with pine tar (I love pine tar) to help increase the friction.  Otherwise it seems that one should alter the shape of the meeting point(s) of the poles to allow/encourage some mechanical attachment or resistance to movement, one to the other?  FWIW   ???

SR

knot4u

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Re: Best lashing knot for three perpendicular poles.
« Reply #22 on: November 19, 2010, 09:29:12 PM »
You're trying to defy the laws of physics if this contraption is for practical use and you're NOT using multiple wraps of rope.  No further explanation, I would be repeating myself.
« Last Edit: November 19, 2010, 09:50:40 PM by knot4u »

squarerigger

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Re: Best lashing knot for three perpendicular poles.
« Reply #23 on: November 20, 2010, 01:22:37 AM »
Quote
I had never thought of adding a third material, solid or liquid,  that could help increase the friction between the rope and the pole ! Is the addition - of pine tar or whatever - a known knotting practice that I was not aware of ?
   
Hi xarax,
The use of pine tar as a preservative of natural fiber line acts also to form an adhesion to underlying surfaces.  In particular note the use of the selvagee (SEL-vah-jee) from ABOK #3521, that was found to adhere with much improved force when made with spun-yarn or marline that had been well-soaked in tar, a practice I use to this day (well, tomorrow, at my weekly volunteer rigging) to obtain a purchase on a shroud prior to adjusting the tension in the lanyard through the dead-eye.  As for the use of tar with other knots - it may well be that tar was used as a preservative that was also found to have side benefits, not the least of which is the adorable smell!  Another practice that is used aboard ship is the parcelling of the shroud prior to applying the serving or service.  A similar layer is added under wire seizings made on shrouds and stays.  There may be more in other fields, such as rosin on pulling cable for electrical wiring or cabling and the use of chalk on climbing ropes.  Specifically are they designed to help a knot?  That depends on what one would term a knot, doesn't it?  If a knot is any confusion for some specific purpose or otherwise in a line then - maybe; but if a knot is simply a deliberate tangle in a line then perhaps not!  Maybe that is a discussion for another topic?

SR

DerekSmith

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Re: Best lashing knot for three perpendicular poles.
« Reply #24 on: November 21, 2010, 09:58:22 AM »
"  I believe/hope that this can be achieved by hard tensioning of the two riding turns per pole, and/or by more than two riding turns per pole, so that these turns function like they do in friction hitches."

Yes, we can always turn to 'More Rope' for a feel good or partial solution



But I hope you are seeking an intelligent solution rather than 'saturation knotting'.  This little example would have been so much better tied with a Gleipnir or the more recent 'Xarax Knot with no name a la Gleipnir'.

So, back to the tripoles.

For nothing more than artistic bondage, the delightful manifold you have given us or the basic manifold used by the scouts in another thread are ideal.  But for a 'real' application, the nature of the materials and the nature, magnitude and direction of the forces involved are critical aspects.  Surely the binding chosen must accommodate the requirements of the(a) 'real' application.

If it is a table, then not only must the binding handle the vertical forces, but it must also resist the horizontal force of being leaned against and so resist parallelogram style deformation (presumably we are not allowed the luxury of diagonal spars or spoke ties?).

The use of Tar soaked cord raises a significant question - might I presume that this challenge must achieve the desired goal without adhesive?  Tar soaked cord today, Superglue or Araldite soaked cord tomorrow and resin soaked carbon fibre for the final solution?

Derek

SaltyCracker

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Re: Best lashing knot for three perpendicular poles.
« Reply #25 on: December 05, 2010, 02:46:48 PM »
xarax,
Thanks for the invitation to post to this subject. I'm afraid that I'd take the traditional process of applying two, adjacent square lashings. One between the vertical (with the vertical spar perpendicular to support surface) and bottom most horizontal spar; the other between the bottom most horizontal and 2nd horizontal spar with the 2nd spar positioned (supported) on top of the bottom horizontal spar. Can be done with one piece of line and there remains sufficient room between the spars for frapping the 2nd lashing.

The above assumes that additional supporting structure will provide lateral support to the vertical spar.

That said, where slick spars, heavy traffic, working due to wind (from experience), etc. are involved the lashing between the bottom-most horizontal spar and vertical spar tends to slip. One solution, when the vertical spar extends sufficiently beyond & above the two horizontal spar, is to provide suspension support to the bottom most horizontal spar by applying an Icicle Hitch to the vertical spar with the "load" end secured and tensioned to the bottom-most horizontal spar. A taut-line hitch can be used to provide adjustable tension.

The idea of using a constrictor knot, as suggested by one poster, around one of the spars instead of a clove hitch to start a lashing is a good one. In the above it would be the starting "knot" applied to the vertical spar, just below the bottom-most horizontal spar.

SaltyCracker
(formerly KnotInGuild... felt that name a bit glib.)

SaltyCracker

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Correction... Re: Best lashing knot for three perpendicular poles.
« Reply #26 on: December 05, 2010, 02:49:31 PM »
... intended to reference a Wagoner's Hitch to provide adjustable tension rather than a Tautline Hitch.

JohnC

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Re: Best lashing knot for three perpendicular poles.
« Reply #27 on: December 18, 2017, 07:03:39 AM »
Best lashing knot for three perpendicular poles.

Hi, can you advise how this lashing is done?

Thanks.
John

eric94110

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Re: Best lashing knot for three perpendicular poles.
« Reply #28 on: May 29, 2019, 12:41:02 AM »
Your photos are cool but I cannot figure out how to actually make this lashing... and video?