Author Topic: Double Loop Knots in Real Life  (Read 9807 times)

roo

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Double Loop Knots in Real Life
« on: October 29, 2009, 06:05:43 PM »
The Ashley Book of Knots has an entire section devoted to Double Loop Knots.  While they are somewhat entertaining, one does wonder about applicability.  

So when was the last time you used a Double Loop Knot?  What was the application?

"Crickets chirping" is an acceptable answer.  ;D
« Last Edit: October 29, 2009, 06:06:46 PM by roo »
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squarerigger

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Re: Double Loop Knots in Real Life
« Reply #1 on: October 30, 2009, 02:19:08 AM »
Good question - the last time?  Probably about ten weeks ago when rigging a plank as a shelf to put pots of paint on for storage until I can be bothered to build a shelf for real.  I used the Tom Fool Knot with loops crossed for an easy to mount/dismount pair of loops - gave me a small bit of insurance against wear (they'll be up there for a good year before I get around to putting a shelf attached to the wall) and they are holding and doing the trick.  Anyone else?

SR
PS  I was wrong about the last time - it was on Saturday last week when I demo'd the knot for a class of would-be Captains I was training in marlinespkie seamanship - the USCG recommends the French Bowline for MOB retrieval and I think it should be the BIB for non-slip loops - any thoughts on that (within the context of the thread of course)? ;D

SS369

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Re: Double Loop Knots in Real Life
« Reply #2 on: October 30, 2009, 04:07:58 AM »
I have to tie loads in the bed of my truck weekly and use a Scottknot most of the time. It keeps the load divided to each loop versus in one loop. And it is very easy to untie afterward.

Not in ABOK either.

Scott

capt larry

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Re: Double Loop Knots in Real Life
« Reply #3 on: October 30, 2009, 01:35:50 PM »
Square rigger,

In a MOB exercise by our Captains Assoc. suggestion of the French BL came up.  My problem with it, and similar knots eg Spanish BL, is that the loops are not independent and can present problems if put around body parts.  In the end I concluded either BIB because it is easier for most people to tie or ABOK 1100, "splayed double loops" would be preferable to French BL.  My preference is 1100 and I found support for this in Riggers Apprentice where Brion Toss recommends it for an emergency Bosun's Chair.

CL

roo

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Re: Double Loop Knots in Real Life
« Reply #4 on: October 30, 2009, 04:28:13 PM »
I have to tie loads in the bed of my truck weekly and use a Scottknot most of the time. It keeps the load divided to each loop versus in one loop. And it is very easy to untie afterward.

I occasionally hear of people wanting to distribute loads via a double loop knot... to essentially make the loop belly "wider".  With communicating loops, I can see that occuring.  With non-communicating loops around the object in question, you have to be pretty lucky in getting both loops to engage equally.

Your Scottknot is not coming immediately to my mind, so I'm not sure which category it'd fit under.
« Last Edit: October 30, 2009, 04:28:52 PM by roo »
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Mrs Glenys Chew

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Re: Double Loop Knots in Real Life
« Reply #5 on: October 30, 2009, 10:13:16 PM »
Good evening, all.

It so happens that I have just started considering a rather urgent application of adjustable double loops.

My 5 year old daughter is getting rather good at making up wooden jigsaw sculptures similar to these: http://www.woodcraftpuzzles.com/  So far we have a rally car, a horse (sadly missing its tail because I took too long to address this question), a mouse, and a paralo - excuse me while I go check the spelling on this - parasaurolophus is next.  I can only spell interminable names I can pronounce.  I'm ok with medical names of all sorts, but not dinosaurs.  Too little contextual evidence for the pronounciation and correct emphasis of syllables.

So, the only safe place to display them (we don't have have things like display shelving) is hanging from the ceiling.  Weights are from less than 100g to about 150g.  Size and length: varies a lot.  Material: very thin plywood, if you ask me.  Comes in a prepunched flat sheet: take piece 1, join to piece 2 so, join piece 2 to piece 3 so, etc.  My husband is doing well with them too. 

I'm thinking of using "Samson thread" - a very strong sewing thread, which will be nearly invisible.

What do you recommend, bearing in mind that the loops ideally need to adjust themselves (communicate?) whilst I'm trying to level the items up kneeling on the top of a bunkbed.

Real life enough?  It's actually fairly similar to the problem I first ever brought to this forum.  I will look back and see what was said then...

Regards

Glenys
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roo

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Re: Double Loop Knots in Real Life
« Reply #6 on: October 30, 2009, 11:02:27 PM »

What do you recommend, bearing in mind that the loops ideally need to adjust themselves (communicate?) whilst I'm trying to level the items up kneeling on the top of a bunkbed.

Real life enough?  It's actually fairly similar to the problem I first ever brought to this forum.  I will look back and see what was said then...

Regards

Glenys

While you could select a communicating double loop out of Ashley's Book of Knots (e.g. Portuguese Bowline), is it possible to just attach, via loop or hitch, to a point on the model in line with the center of gravity when the model is fairly level?

Another option that would be less visible than a double loop knot would involve merely cutting the thread into 3 parts.  One vertical line from the ceiling, and two angled legs that attach to the model.  One or both of the angle legs of thread (or fishing line) could employ a Slippery 8 Loop to make fine adjustments.

http://notableknotindex.webs.com/slippery8.html

Yet another permutation would involve making the angled legs one line that slides (as needed) though a tight noose (http://notableknotindex.webs.com/hangmansnoose.html) or friction hitch from the vertical line.  Numerous ways of skinning this cat come to mind.
« Last Edit: October 30, 2009, 11:12:55 PM by roo »
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Dan_Lehman

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Re: Double Loop Knots in Real Life
« Reply #7 on: November 01, 2009, 03:23:56 AM »
Good evening, all.
It so happens that I have just started considering a rather urgent application of adjustable double loops.

Whoa, state the rope-problem but don't presume the solution.   ;)

Quote
My 5 year old daughter is getting rather good at making up wooden jigsaw sculptures ...
parasaurolophus is next. m ...  I'm ok with medical names of all sorts, but not dinosaurs.

Goodness, I didn't think that "GODZILLA" was the scientific name for anything!
But, then, there seems to have been a revolution in dinosaurs (-- mocking a Yankee
GM car ad, "These aren't your father's dinosaurs!") since my single-digit years
(though Mr. G'zilla was all the rage way back).

Quote
So, ... to display them ... hanging from the ceiling.  ... My husband is doing well with them too.  
Ah, good to hear that.   :D


Quote
I'm thinking of using "Samson thread" - a very strong sewing thread, which will be nearly invisible.
What do you recommend, bearing in mind that the loops ideally need to adjust themselves (communicate?)
whilst I'm trying to level the items up kneeling on the top of a bunkbed.

My examination of the several dinosaurs (and their God-zilla) convinced me that
those at least are not suitable for easy 2- or 3-point support, being so long and
narrow, towards 2-dimensional!  Argh.
But here's an idea:  support each item with a 3-point bridle
comprising:
CL) a closed loop, and a
ST) suspension tail.     [argh, rather daft names]

The CL will be attached to the ST with a friction hitch -- e.g., Prusik hitch.
The CL will effect TWO points of support, possibly with just a simple
Round Turn on a dinosaur arm (lest PITA [er, PETA] protest ...) to stabilize the
sculpture against horizontal rotation; the ST will effect the 3rd point
of attachment (I guess you should put in an Angler's Loop (#1017?)
for easy attachment AND DEtachment).  With e.g. the CL bridle part
holding Godzilla's arms and the ST securing tail, the Prusik can be
slid up or down the ST to appropriately orient Godzilla, depending
upon his mood of the moment.

--dl*
====

[edit to have People for the Ethical Treatment of (even long deceased?) Animals
vs. round bread types; sorry, to make Glenys Chew on "pita".  :o]
« Last Edit: November 12, 2009, 11:11:14 PM by Dan_Lehman »

Mrs Glenys Chew

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Re: Double Loop Knots in Real Life
« Reply #8 on: November 02, 2009, 11:13:32 PM »
Dear Dan and Roo

Thank you very much for your answers.  I will print them out and try them out, but I can't promise to remember to report back on what worked best for each jigsaw  :)

I tend to think of one solution, and then not be able to see other ways of doing it.  So my immediate solution (double knots) was not exactly presuming a solution, but just not looking at all of them.  You've got the grey matter stirring, though, and that has been a help.

Godzilla - ah those childhood memories of men in lizard suits kicking Dinky cars around :)  The remake was nice, but not nostalgic.  What organisation is PITA, though?  Paleontologically Interested Teachers of Archaeology?

Regards

Glenys
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Andy

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Re: Double Loop Knots in Real Life
« Reply #9 on: November 12, 2009, 08:12:39 PM »
Hi again Roo,

Quote
So when was the last time you used a Double Loop Knot?  What was the application?

Here's the application,


and, ironically, You are the one who, on this thread, brought my attention to the fact that it was a double loop! LOL
I had read your question before asking mine, and it hadn't even crossed my mind to put the two together. :)

Warmest regards

Andy
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Dan_Lehman

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Re: Double Loop Knots in Real Life
« Reply #10 on: November 13, 2009, 07:28:07 AM »
Okay, Andy, what are we looking at here?

I see the Grapevine bend; I don't really see how the line
beneath it interacts with it, except that that strand does
seem to *jog* (up-down) in passing beneath or through(?) it?

But I certainly do NOT see any "double loop", not in the sense of the OP.

--dl*
====

Andy

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Re: Double Loop Knots in Real Life
« Reply #11 on: November 14, 2009, 12:30:43 AM »

Hi Dan,

You are right, no doubt.

I was trying to explain that Roo had shown to me, on this post, that my necklace problem could in fact be expressed as a "double loop" problem. In that sense, the necklace problem was a recent application of a double loop (even though the picture didn't show a double loop in the OP sense).

I was lazy to take another picture, but you pushed me to it. Thank you, this will make for a more technically-correct post.
Here then is the necklace problem mentioned earlier, solved with a two-loop butterfly.


Since then, others on the thread have offered more eye-pleasing solutions. Wondering if you'd have any other ideas. :)

Wishing you a fun day,


Andy

ps: for the archives, here is a close-up of the grapevine variation on the necklace.
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Dan_Lehman

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Re: Double Loop Knots in Real Life
« Reply #12 on: November 15, 2009, 07:19:25 AM »
ps: for the archives, here is a close-up of the grapevine variation on the necklace.

Although it's a nice macro shot of the knot,
my question still begs an answer:  What are we looking at?

Please explain what is going on here.
(I see two Strangle knots tied around the strand running upper left
to lower right; I do NOT see what ties these knots --for the Grapevine,
it would be opposed ends of the aforementioned strand-- and don't
see how the strand running across the first (seemingly beneath it, but ...)
plays in any of this.  It could be that the lines running from upper
right and lower left are tying the Strangles around the aforementioned
line; except that the particular angles/alignment of the upper-right one
doesn't seem to really fit into the left-hand Strangle.)

--dl*
====

Andy

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Re: Double Loop Knots in Real Life
« Reply #13 on: November 15, 2009, 06:38:29 PM »
Quote
What are we looking at?

Hi Dan!

You are quite a scientist, insisting to understand what is happening behind the picture...

We're looking at something that wouldn't work so well if it weren't for the leather's non-slip action.

"Strand One", the strand at the bottom-left of the picture, is responsible for almost all of the black leather you see in the picture.
"Strand Two" starts at the top left of the picture and is very short.

Strand One comes in from the bottom left, goes through the key chain, makes a bight, and ties a double overhand onto Strand Two. That is the leftmost knot.
For its part, Strand Two just comes in from the left and ties a double overhand onto Strand One (the rightmost knot).
The two knots are brought close together as for a normal grapevine.

If this were tied in other material, there would be a lot of slippage as the rightmost knot essentially creates a noose-type formation, a variant of the double overhand sliding loop.
Neither the most clever design, nor the most functional or stylish :) (Though the two X'es of the double overhands are growing on me.)

Hence my call for ideas on the other post.
That's where Roo pointed out the double-loop solution, of which the double butterfly picture in my last post was an example.


Wishing you a wonderful Sunday,


Andy
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Dan_Lehman

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Re: Double Loop Knots in Real Life
« Reply #14 on: November 15, 2009, 09:37:27 PM »
Okay, this has gone into the realm of tedium, now, but I'll
give it one more stab.

So far as I can determine --with straight edge on monitor image--,
the lower-left strand and upper right strand are off of alignment
by a little more than a diameter:  i.e., top of lower left strand
extends beneath bottom of upper right.  SO, I must think
that they're not connected.

And from your reply the best I can deduce is that the lower right
strand bends through righthand Strangle to go ANTI-clockwise
through the key ring, and then comes back (as upper-right strand)
to Strangle the upper-left strand, which makes the Strangle just
passed through.

Superficially, the structure can be seen to be tied in another way:
the Grapevine bend is tied such that the lower-right<->upper-left
strands are one/continuous, passing between the two S.Parts of
the Grapevine, which cinches tight upon the pass-through part.

Another way to employ the Grapevine would be to tie it around
the pass-through strand so that the S.Parts & pass-through lay
parallel/adjacent for the full run of the knot; this would also
provide ample friction esp. in leather (but also in cord) to keep
the respective loop sizes, but also allow deliberate adjustment.

--dl*
====