Author Topic: Aerial knots for knots...  (Read 1278 times)

gervais

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Aerial knots for knots...
« on: August 02, 2019, 10:47:22 AM »
Morning All,

First time poster, so be gentle.
Looking for some advice for an interesting application.

I have a large loop 24ft/7.5m continuing to 150ft/56m of rope "bridle".
The loop (and brindle) go from 0kts to 75kts (86m/hr  -  139km/hr) over a 1-2 second period, it will be initially pulled back against the loop, then forward to bring the loop tight, to parallel the lengths.

The loop is likely to then be pulled under tension sometimes off the longitudinal axis up to 40 degrees and always experiencing pulsing and/or high variance in loading.
It is then pulled for a time period ranging 15 mins up to 95 mins.
The arrangement regularly goes from dry to damp to wet.
It is hard to estimate the exact loading but the rope have never failed in use, but a knot shouldn't reduce the strength by much if possible, otherwise I will be filling out mountains of paperwork.
Ideally the knot needs a profile that avoids snagging (on the ground) and the termination/working end tucked away neatly if possible
The loop cannot move or close. Security is paramount and untying not required, so binding allowed.

I have trialled a number of knots, none of which have failed under tension (or at all in fact) but feel have not remained "neat" or "tidy" after a dozen or so uses. Periodic replacement of the arrangement occurs due to ground abrasions to both knot and rope/bridle, which is why a knot is required (e.g. if in the field).
They have all been adequate/satisfactory knots, but not "wowed" me so far; so I wonder what IGKT has to suggest.
I won't embarrass myself to you by disclosing these here, but I did initially look to some marine based knots and have some intermediate parachute rigging experience, as well as a long time established love of knots.

I reluctantly will disclose the rope is about a 10-15mm polyester plaited pre-stretched affair but am NOT looking for advice of material changes, splicing or operational changes etc., just what you think would be the best knot.

Q: So what knot do the most think fits the bill to create the 24ft loop at the end of the long length?
Including any other knot added after.
(Also extra credit will be awarded for any details of dressing, or husbandry etc. e.g. whipping you could suggest)

Much obliged and happy to send pictures of the knot in use or after use.

roo

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Re: Aerial knots for knots...
« Reply #1 on: August 02, 2019, 03:21:42 PM »
What unsatisfactory loops have your tried?  I ask so that we don't rehash failure.
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gervais

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Re: Aerial knots for knots...
« Reply #2 on: August 02, 2019, 03:55:12 PM »
The inevitable question preferably avoided......

However, some "bowlines", a go on "The non-Slip-Loop", the "angler's loop" (which performed well enough but the working end stuck out), to name but a few.

Looking for a steer or experience with larger loops. If suggestions overlap previous attempts, so be it, happy to revisit.
Also: I have also noticed I seem to impart or trap a slight but noticeable twist in the loop. which I don't notice when tying small knots.



roo

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Re: Aerial knots for knots...
« Reply #3 on: August 02, 2019, 07:40:24 PM »
The inevitable question preferably avoided......

However, some "bowlines", a go on "The non-Slip-Loop", the "angler's loop" (which performed well enough but the working end stuck out), to name but a few.

Perhaps there is a direction of the free end that is preferable for you.  It has to exit somewhere.  If you want the free end pointing toward the standing part, you might try a Figure 8 Loop or augmentations thereof (Fig 9, or others that involve additional initial twists).
« Last Edit: August 02, 2019, 07:42:27 PM by roo »
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Dan_Lehman

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Re: Aerial knots for knots...
« Reply #4 on: August 02, 2019, 09:12:56 PM »
I have a large loop 24ft/7.5m
continuing to 150ft/56m of rope "bridle".
At this foundational point, I'm lost.
I'd love to see an image of this, of course;
but more words can help (as I often say).
What is "loop" : variously it means something like a bowline
or otherwise a round sling (end-2-end'd piece of line).

What is "continuing to..." ?

Quote
The loop (and brindle) go from 0kts to 75kts (86m/hr  -  139km/hr) over a 1-2 second period, it will be initially pulled back against the loop, then forward to bring the loop tight, to parallel the lengths.
1) 'brindle' => 'bridle'
2) 0kts to 75knots in 2 seconds? !!!!  --Rocket Man!

Quote
I reluctantly will disclose the rope is about a 10-15mm polyester plaited pre-stretched affair but am NOT looking for advice of material changes, splicing or operational changes etc., just what you think would be the best knot.
... which sometimes requires knowing what the rope is.


Quote
Much obliged and happy to send pictures of the knot in use or after use.
... of current situation, even?!


 ;)

agent_smith

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Re: Aerial knots for knots...
« Reply #5 on: August 03, 2019, 03:34:58 PM »
Quote
Q: So what knot do the most think fits the bill to create the 24ft loop at the end of the long length?
Including any other knot added after.
(Also extra credit will be awarded for any details of dressing, or husbandry etc. e.g. whipping you could suggest)

I am surprised that no one has asked what the context and application is...
Without understanding the context, it is hard to provide any meaningful advice.

You leave a few breadcrumbs with words such as:
[ ] "aerial"
[ ] "ground abrasions to both knot and rope/bridle, which is why a knot is required (e.g. if in the field)"
[ ] "otherwise I will be filling out mountains of paperwork"
[ ] "Security is paramount and untying not required, so binding (jamming) allowed"
[ ] "Ideally the knot needs a profile that avoids snagging (on the ground)"

... All of which leave an impression that this is height related and life critical? (due to mountains of paperwork and 'aerial' in the title)

It seems that you require a 24 foot /8m fixed eye (loop) - which has a small footprint so it reduces risk of snagging.

Without properly understanding your context/application; perhaps an eye knot derived from #1410 Offset overhand bend might meet your requirement for snag resistance.
All end-to-end joining knots have 4 possible derived eye knots. Using #1410 as the core, you could tie an eye knot that has a partial offset profile.

Another eye knot that has a relatively small footprint is a Zeppelin eye knot (Zeppelin loop).
Note that an eye knot derived from #1410 and the Zeppelin eye knot aren't 'PET'.

If you prefer an eye knot that is PET (Post Eye Tiable), you would need to use a type of 'Bowline' (Scott's locked Bowline is simple and inherently secure).

I am curious as to what your context and application is...

EDIT: What do you mean by "credit will be awarded" ?
« Last Edit: August 03, 2019, 09:22:53 PM by agent_smith »

alpineer

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Re: Aerial knots for knots...
« Reply #6 on: August 04, 2019, 11:13:00 PM »
1. Two Strand Double OverHand Knot
2. Two Strand Double Matthew Walker Knot.
3. I have a secure Bowline variation that could work for your application, but I'll leave that for now.

Cheers,
alpineer
« Last Edit: August 05, 2019, 04:08:27 AM by alpineer »

gervais

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Re: Aerial knots for knots...
« Reply #7 on: August 05, 2019, 11:14:59 AM »
Hi,
See attached

The "loop" (our terminology; not necessarily IGKT approved) is strung across the poles, this then is attached (attached has a specific NATO meaning which isn't correct here) to the Bridle (not brindle - sorry, big fat tired fingers) by continuing as a one rope, this then proceeds on to the aerial banner. The "loop" is then caught by the AC which is dragging a hook through it and the banner lifted up.

Not really breadcrumbs more distillation of the specifications or imparted demands upon the arrangement.

I trust this helps and casts more light.
Cheers.

Dan_Lehman

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Re: Aerial knots for knots...
« Reply #8 on: August 05, 2019, 10:24:41 PM »
Okay, now I see the situation, thanks!

IMO, you might do best with an end-2-endS knot :
i.e., join the long rope the two ends of a rope used
for the "loop" (eye).

Stanley BARNES showed such a knot in his 1951 book,
and I see just now that Geoffrey BUDWORTH presents
it in one of his gazillion books.  (It is a testimony to the
unnecessary limits Agent_Smith keeps typing as
"All end-to-end joining knots have 4 possible derived eye knots" :
THIS is a corresponding eye knot (template --one need only
fuse one pair of ends to have a single rope) to the blood knot.)
[lonnng URLink via Google for GB's book pate]
https://books.google.com/books?id=3Q17nexDaswC&pg=PA72&lpg=PA72&dq=knots+barnes+stanley&source=bl&ots=-6bGYDEeSM&sig=ACfU3U0w0NMQcTTV5yjEnYSuzvXPj-hDgQ&hl=en&sa=X&ved=2ahUKEwjQm9OG0uzjAhUsmeAKHYNrD-EQ6AEwD3oECAkQAQ#v=onepage&q=knots%20barnes%20stanley&f=false


Budworth's version --and, for that matter, blood knot
versions-- has tails going out in opposite directions,
but they can as readily exit in the same.
Per material(s), YMMV on exact number of wraps (but
surely the eye tails will have fewer --though twin--
turns for their lesser tension).

Beware that many uninformed presentations of the
blood knot show it with what Barnes calls "out coil"
tying : where the two ends wrap away from each other
and then make a long arc/reach back to the center
tucking.  DONE IN FISHLINE, this will transform during
setting to what can be directly tied in the "in coil" way:
ends reach past each other and then the tails wrap back
to the center exit.

For YOUR material, out-coil tying is likely to survive
as just that : what you see is what holds, and that
might be sub-optimal.  Also, set by hauling hard on
the EYE opposed to the KNOT, to give those only-half-loaded
parts a head start over the fully loaded SPart (when push
comes to shove).

.:.  Like the double overhand knot (well, in the strangle knot
form), this knot will present adjacent & equal wraps of
material to face abrasion.  (Partly why the fisherman's
knot
is favored by commercial fishermen.)  Don't
expect to untie it (though w/tools, maybe)..

And perhaps the option of TWO ropes has some
benefit you can realize --i.e., that the eye rope
can be different than what is joined to it (maybe
a little lighter?).

--dl*
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Dan_Lehman

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Re: Aerial knots for knots...
« Reply #9 on: August 05, 2019, 11:03:05 PM »
I should add that the number of wraps used for
the blood knot is usually reduced as material size
increases.  I'd try 3-4 in your material, for the SPart;
for the eye legs, possibly 2 (around, over themselves,
around again, and tuck out --possibly going another
half wrap to tuck out in opposite direction (not a full
turn to tuck out same, i.e.).

As for all tails on same side, likely this needn't
concern you; not sure it matters much on dressing
& setting.  You'll likely have a feel for this.
And the tails need not be long.

--dl*
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gervais

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Re: Aerial knots for knots...
« Reply #10 on: August 06, 2019, 05:32:27 PM »
That's truly great stuff.
Thank you.

I have thought about 2 ropes and even tying the brin...BRIDLE and Eye (yes of course, it's an eye! Ta), even then tying to a intermediate ring. However, that then adds bulk.
I will give your suggestion a whirl.

Interestingly (depending upon your point of view) the current knot IS from GB's fishing book you suggest, I recall the description most fitted the bill, but alas unforgivably I CANNOT not recall which one I selected, it MIGHT have suggested use on filaments (eek!) and perhaps I over did the external wrapping all reasons why I hesitated in proffering up details here. I will go back and look to see what I tied... It's held well but clearly it pulls asymmetrically, I have thought the wraps are at fault. I heed your advice.

The knot size and profile have seemed important; having an effect on the banner pick up and successive flight.
Also; the rope does some astonishing things and you wouldn't believe some of the "knots" that get tied in the lines. I would love to film it. They appear to be mathematically impossible to achieve and a total head shag to resolve/remove/clear, not to mention the binding and friction heat apparently generated. generated. I will see if I have some photographic evidence.

thanks again for your time.