Author Topic: A 'Better' Loop Knot ?  (Read 19993 times)

DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #15 on: December 08, 2006, 11:03:08 AM »
We have some bad weather in the UK at the moment and I spent most of Thursday adding hold down lines to a Poly Tunnel.

Strong winds blowing over the tunnel have the effect of an airfoil and lift the poly covering from the  supporting tubes and then flap it, causing it to slap hard onto the tubes.  This is a wear issue and adds stress to the fixing points so it is prevented by tying 8mm ropes over the top between the supporting hoops and anchoring them to the base.  The tunnel was 140ft long and 30ft wide with a hoop every 5ft.

During a storm, the ropes (and their knots) will be subject to wet and constant shock loads.

The ropes are fitted to anchor points by a terminal loop knot and for this job I used the new Strangle Loop.

A strangle was tied about 2ft from the end.  The end was then passed around the anchor and fed back through the strangle hole, then made fast with the gooseneck.  The strangle was then tightened and the loop adjusted for size before finally seating the gooseneck tight against the strangle by pulling against the anchored loop.

The knot was a pleasure to tie - even with cold fingers - and the ease of in-situ adjustment made it perfect for the job.

The ability to hold fast in wind and rain is the key challenge - I will be checking the job regularly and will report any failures.

Derek

Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #16 on: December 08, 2006, 06:12:19 PM »
The knot was a pleasure to tie - even with cold fingers - and the ease of in-situ adjustment made it perfect for the job.
Roo & I eagerly await your report on the pleasure quotient of untying these knots,
esp. w/cold fingers!

 ;D

DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #17 on: December 08, 2006, 10:34:11 PM »
LOL,  you are sad, the pair of you - suggesting that it would give me any sort of pleasure opening up those knots.

Still, I am almost certainly the sad one (my good lady says so).  I just had to go and check those knots today, they are not getting much tension but they are getting a lot of shaking and of course rain.  None of the knots had shifted, and just like a kid who has to dig up the seeds a few hours after planting them - just to check - I couldn't resist untying a couple, just to see if they had jammed yet (they hadn't).

The expected use is for these ropes to be cut off and discarded  when the poly cover is renewed in 10 years time, the only job of the knots is to reliably resist all the shaking without weakening the rope unduly - I will just have to seek my pleasure quotient from some other perversion.

 ;)

DerekSmith

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Re: A 'Better' Loop Knot ?
« Reply #18 on: December 11, 2006, 06:14:20 PM »
Derek:  Where do you get lost?  It can't be that hard to follow words!
Your finish takes the end under itself in a Half-hitch; my revision takes it over
itself ("over"~="outside, away from core") then back under, BUT in this case
I say to include the parallel strand of the knot (the twin of the two eye legs)
in what is cross over/outside, and to then tuck under both, or "between"
those twin parts and the SPart.
--dl*
====

Originally you were talking about tying this knot in the bight.

I could take this term to mean two things - first that you have formed a bight and then used this double cord to tie the knot with the end of the bight loop as the end of the cord, I don't think you mean that because it makes a horrible mess even with the single strangle. Alternatively I could take it to mean that you are tying the knot in-line without access to either of the ends.  Taking the latter meaning, I can form the strangle (single, double etc.) by winding the cord around my hand, then form the slipped loop by passing a loop through the centre of the strangle coils.  Drawing the knot up forms a slipped strangle in-line.  If I then take the slipping line and make a twist in it, then pass the whole of the strangle and its loop through that twist, then the twist forms a single overhand knot where in my version I had formed the half hitch.  Drawing up this single OH knot to the strangle forms a construction which fits the description you give, i.e. the red cord passes over itself then under itself.  So far, so good.

I am stuck on the term 'the parallel strand of the knot (the twin of the two eye legs) - what is the parallel strand of the knot and what are the two eye legs?

Perhaps when I work out what they are the last part will clarify.

Derek

Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #19 on: December 12, 2006, 06:59:54 AM »
Let me just work to get you to the right knot form, nevermind the full
tying method one might employ.  What you quoted latest from me was
in reference to your latest images, where you show the tied knot in
two aspects, reddened end of upper knot pointing upwards, of lower
pointing downwards.
Refer to the upper knot.  The red end exist between a white part (SPart)
and its earlier part (red), closing what you call a "gooseneck".  What I
tried has the end passing--in the image's orientation--BEHIND its own
part, then crossing down over it, and also over white part that is the end
of one of eye's legs (the red end is the other leg's end).  You'll need to
loosen that Dbl.Strangle in order to make the tuck!
The red end then is tucked away from the viewer between this white
parallel part and the SPart.

To put it another way, I think that it can be seen readily that if the end's tuck
is removed, that you have a Dlb.Strangle slipknot; the bight of this knot has
parallel legs, one red/white; my revision takes the end around to cross over
both legs and tuck immediately between the SPart and them.

----------

I'll reiterate that I did find this knot to jam in some soft 12-strand multifilament
something-or-other (burn test, well, hmmm, suggested maye PP !) (part of
uncertainty is that I'm not keen on burning more than a small bit of the rope
--sorry, Science--, and that maybe isn't enough to make things clear)

----------

As for "in the bight" meaning, one might consider that "with the bight" is
a subset of "in the bight" (obviously).  In this case, there is a "with"
aspect but it comes later on--the last wrap and tuck out of the bight through
the eariler-formed wraps can be done "with".  And I described one way I
think in which you formed the start of the coil, then set the end into a spot,
then continued with the thus-formed bight.  However, such tying tends
to torqure the rope and one ends up wrestling with torsioned rope.  (Just
as one will see eye splices that have a twist in them (they NEED a twist
if the eye is form a Clove Hitch, though). (I'm not sure if this might arise
also from stiffening with ageing.)

--dl*
====

Funambulist

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Re: A 'Better' Loop Knot ?
« Reply #20 on: December 18, 2006, 12:03:19 AM »
One of the best loop knots I know is the double re-threaded bowline. It backs up the loop so that if it is in a place where it could rub you have extra strength and it bites on itself in such a way that it can't come undone by accident, but can be released after ANY amount of tension.

I can post a picture if you want?

Jon

Funambulist

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Re: A 'Better' Loop Knot ?
« Reply #21 on: December 18, 2006, 01:08:42 AM »
...and if you don't want to use as much rope there is also the classic water bowline where you make a bowline, but at the point where you make the loop you make a clove hitch and proceed as normal. That's a really stable knot, as well as being quick and easy to tie, it's actually easier than normal bowline because there is no right or wrong way through the loop because it's a hitch ;) slightly harder to undo than the double re-threaded after it's been loaded though!

Dan_Lehman

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Re: A 'Better' Loop Knot ?
« Reply #22 on: December 18, 2006, 07:51:16 AM »
double re-threaded bowline.  ... there is also the classic water bowline ... . That's a really stable knot, as well as being quick and easy to tie, it's actually easier than normal bowline because there is no right or wrong way through the loop because it's a hitch ;) slightly harder to undo than the double re-threaded after it's been loaded though!
Well, there are infinitely many bowlines among which some of the more
interesting/useful ones haven't been presented (or presented widely).  What
you call "double re-threaded" is to most knotty folks a Bowline on a Bight,
but tied with the end; given that one needs (in climbing, to tie into a harness)
to use the end, it's rather stupid to stick to the in-the-bight form--there are
better finishes, which give the working end a loftier lot than playing twin to
the main line!   ;)
It's not clear how all so "classic" the Water Bowline is (at least, CLDay casts
some skepticism about its heritage), but I don't see how it's nearly as easy,
even, as tying the common Bwl; and as for "wrong way", well, I can envision
some rather wrong ways about it--such as orienting the Clove part the opposite
way, which can lead to a jammed knot.  OTOH, I've just been playing around
with this base as a solution to the Bwl-loosening-in-kernmantle problem, and
there are some fun variations along this line.  The "wrong way" you imply for
the Bwl arises from a tying method that itself shouldn't be part of the climber's
main set; you should be getting the rabbit through the hole AS you form
that hole--in one smooth motion which ensures "right way" orientation.
And "wrong way" thereafter--i.e., tying the "Dutch Navy"(misnomer)/"Cowboy"
vs. "Right" Bwl--, is not so much a real issue or as preferable one way as
many tyers seem to believe.

--dl*
====
« Last Edit: December 19, 2006, 05:41:53 PM by Dan_Lehman »