Author Topic: Snug centre-pull hitch wanted  (Read 162 times)

JohnC

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Snug centre-pull hitch wanted
« on: February 21, 2021, 03:25:00 AM »
Hi Folks

Pulling woody weeds with my new-favourite knot, the Prohaska, I encountered a weed that defeated my mechanism and snapped off half way up the stem.

My method is to tie one end of some synthetic braided cord (I don't know what it's called) to a length of steel pipe with a snug round turn and two half hitches, then to the weed stem with the Prohaska, then lever it out with the pipe on a fulcrum (usually a wooden billet, aka a piece of firewood).

No big deal about the weed snapping (probably my technique at fault), but when I came to remove the cord from the pipe the RT&2HH was completely jammed, and when I finally managed to get it off I found it was actually fused at one point.  I suspect this may have been because a round turn and two half hitches exits from one side of the cylinder it's attached to until the load reaches a certain point when it distorts and drags the two half hitches to the centre. I'm guessing that happens in a split second and provides enough friction to melt the cord.

So, is there a snug** hitch that will resist distortion and jamming under load?

--
**I don't want it slipping off the pipe
 
« Last Edit: February 21, 2021, 03:25:50 AM by JohnC »
John

Dan_Lehman

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Re: Snug centre-pull hitch wanted
« Reply #1 on: February 21, 2021, 07:23:16 PM »
How about an extra turn,
then a backhanded turn around the hitching line,
and THEN tie off w/2HH?!  (By "backhanded" I mean
that one brings the line around the SPart in a U-turn
and back around now the opposite direction of the pipe
and come up the other side to tie off w/2HH, which now
will sit *atop* this initial U-turn, and will receive well
less force for the extra turns introduced.)

Alternatively, the anchor bend / fish. bend I'd think
would suffice, possibly w/extra turn as well, to absorb
more force around the pipe.

?!  Jamming the attachment, fusing material :: how large
is this cord you're using?

(And what "Prohaska" hitch is this --of his many?!)


--dl*
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SS369

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Re: Snug centre-pull hitch wanted
« Reply #2 on: February 21, 2021, 08:59:38 PM »
Hi Folks

Pulling woody weeds with my new-favourite knot, the Prohaska, I encountered a weed that defeated my mechanism and snapped off half way up the stem.

My method is to tie one end of some synthetic braided cord (I don't know what it's called) to a length of steel pipe with a snug round turn and two half hitches, then to the weed stem with the Prohaska, then lever it out with the pipe on a fulcrum (usually a wooden billet, aka a piece of firewood).

No big deal about the weed snapping (probably my technique at fault), but when I came to remove the cord from the pipe the RT&2HH was completely jammed, and when I finally managed to get it off I found it was actually fused at one point.  I suspect this may have been because a round turn and two half hitches exits from one side of the cylinder it's attached to until the load reaches a certain point when it distorts and drags the two half hitches to the centre. I'm guessing that happens in a split second and provides enough friction to melt the cord.

So, is there a snug** hitch that will resist distortion and jamming under load?

--
**I don't want it slipping off the pipe

Hi JohnC.

I have used a Prusik hitch in this instance before, using the two legs to tie to fence posts and small trees and been able to untie relatively easy.
To use this as a single line (to attach to the item to be pulled) you a can tie a bowline (of choice) and then the Prusik with the eye legs. Then you have a single line to attach. I don?t think you?ll have any trouble undoing it.
But, there are many hitches that will suffice, i.e., clove hitch, cow hitch, etc.

SS

JohnC

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Re: Snug centre-pull hitch wanted
« Reply #3 on: February 21, 2021, 11:52:57 PM »
Quote
(And what "Prohaska" hitch is this --of his many?!)
The one that sometimes dons a false nose and beard and goes by the name Blake's Hitch.

Quote
?!  Jamming the attachment, fusing material :: how large
is this cord you're using?
Quite small compared to the pipe. About the width of thick spaghetti. It has to be small to wrap around slender weed stems (they are small weeds but have a tenacious hold). It's the strongest small cord I've got. The pipe is just one I happen to have of a handy length. 

Doing a bit of research to see if Prohaska was indeed the right name (in my view the first to describe a knot gets the credit) I found that there is also a 5/3 version, which might be even better. Basically I'm trying to emulate very strong human hand grip - i.e. pull in line with the stem, with pressure over a large area to minimize the chance of snapping the stem.

Also in my research I discovered the animated knots website, which is perfect for me as I recently lost Knots 3D off my phone (long story, don't ask) and I hate youtube with a burning passion (even longer story), so a site with animated images and speed control is perfect.

This is the post that keeps on giving.

Back to the subject: I will try both suggestions, thank you Dan Lehman and SS. 
John

Dan_Lehman

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Re: Snug centre-pull hitch wanted
« Reply #4 on: February 23, 2021, 10:19:30 PM »
Quote
(And what "Prohaska" hitch is this --of his many?!)
The one that sometimes dons a false nose and beard and goes by the name Blake's Hitch.
Ah, good.  I've given it the name "Prohgrip" or sometimes
maybe "Prohclamp" --thinking the German "klemnoten"
more directly goes to "clamp"; yes, at least Google did
that just now, for 'klemm' (but not for 'klem').
Anyway, in English, aurally, "Proh" sounds like "pro" and
garners respect.   ;)  (Heinz likes it.)


Quote
Quote
?!  Jamming the attachment, fusing material :: how large
is this cord you're using?
Quite small compared to the pipe. About the width of thick spaghetti. It has to be small to wrap around slender weed stems (they are small weeds but have a tenacious hold). It's the strongest small cord I've got. The pipe is just one I happen to have of a handy length.
I almost suggested in initial reply that one might use
a pair of cords : one sized for the hitching & binding,
possibly loaded on both strands (so, e.g., klemheist),
with another joining that to the pipe.


Quote
Doing a bit of research to see if Prohaska was indeed the right name
(in my view the first to describe a knot gets the credit),
I found that there is also a 5/3 version, which might be even better.
And when "first to describe ..." turns out to have been
unknown until later ... ?

"found there IS a ... " !!  Heinz made a similarly surprising
(IMO) remark in some brief history of friction hitches,
remarking that "the 3-turn Prusik h. hadn't yet been invented":
why this surprises me, is that I think it should be obvious
to extend such a knot by making an additional wrap,
lengthening the coil.  (Whereas the strangle knot might
be seen as somewhat novel vs. the overhand --a knot
that lacks any "overwrap" (as I call it)--,
the further extensions of this multiple OH structure should
be pretty well indicated --hence, "dbl. / trpl. / ... strangle",

But in presenting the Prohgrip to Nylon Highway (a NSPS
--USA caving-- newsletter), Heinz expressly advised that if
the hitch slips seemingly for stiffness of the cordage
then add a turn with a tail tuck within it; but if ... from
slickness, add a turn at the other end, w/o tail tuck.
(Stiff rope won't like making those 1dia wraps, hence
the first recommendation.)
Sometimes, to bolster friction gripping, I put in a
turn/HH or dbl.turn (of either of two forms --that
jammed-into-first-turn form, or just a follow-on turn_
to *guard* my whatever friction knot.

Quote
Also in my research I discovered the Animated Knots website,
Yep, Grog's put in a lot of work on that site.
From time to time I put in a suggestion/correction.


--dl*
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JohnC

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Re: Snug centre-pull hitch wanted
« Reply #5 on: February 24, 2021, 12:58:51 AM »
Quote
"found there IS a ... " !!  Heinz made a similarly surprising
(IMO) remark in some brief history of friction hitches,
remarking that "the 3-turn Prusik h. hadn't yet been invented":
why this surprises me, is that I think it should be obvious
to extend such a knot by making an additional wrap,
lengthening the coil.

I know what you mean. When I wrote that it seemed slightly silly to me too, but after thinking about it briefly, I decided to let it stand. Just for the intellectual exercise, let's delve into it:

I actually do think it would benefit mankind if people more often stopped to consider, each time they learned something new, "What if I did it slightly differently?" Many more useful things would have been discovered. But two aspects of human nature work against that.

1. Time and interest: If the standard Prohaska pulls the weeds, I can finish them off then go back inside and learn a completely new knot that would be more interesting (to me) and probably more useful than experimentation on variations of tucks, turns, etc. But for someone else it would be rewarding to work through all the variations and discover and document their properties. We might call this the "return on investment".

2. Trusting in experience: If I first encounter the knot as two turns in front and two turns behind the tuck, I'm going to assume that this is what works best, because I also assume that lots of people have tied this knot and if three turns had been better (in general) then that would have become the consensus. Perhaps more than two either side would be dangerous in some way; it might look stronger but be weaker and more prone to failure and therefore I'd end up clobbering myself with my steel pipe.

But when I see the 5/3 presented by people who have used it and noted its superiority in certain circumstances, then I think it's fair to write "there is also a 5/3 version" as being short for "people have tried a 5/3 version and found it to be good so I think I'll try it as well".
« Last Edit: February 24, 2021, 01:00:54 AM by JohnC »
John

JohnC

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Re: Snug centre-pull hitch wanted
« Reply #6 on: February 24, 2021, 03:54:34 AM »
Actually (he said, warming to his subject), there are two other aspects of human psychology that can play a part.

3. Focus: Because I wanted to memorize this knot in order to go outside to apply it, there was no room for suppositions about variations: it would be annoying to get there and forget how to tie it, and I wasn't about to take my computer outside, so I only had mindspace for learning what was presented.

But to tell you truth, even if I had been just sitting on the couch playing around with tying a thin cord onto a thick one, I probably wouldn't have tried any extra turns because of my last point ...

4. Priming: Have you ever had the experience of, for instance, being in the market for a new car, having a favourite candidate, and suddenly the roads are full of them. You never saw them before you read all those reviews and got all excited about this particular car. Now every time you go out they're everywhere (and the black looks way cooler than the red, though a pain to keep clean). 

Some time in the past, though you may not remember it, you "discovered" that an extra round turn can significantly change the properties of a knot, so now you see that possibility every time. Now I will too! I'm primed!

And just because I can't resist, consider this very thread itself: For me, it's fascinating to think through all the reasons why I couldn't see what in hindsight should have been obvious. Many people would have just said to themselves, "Didn't think of it, dunno why".  Many people are saying to themselves right now "WILL YOU SHUT UP ABOUT IT!"

So I will.
John

JohnC

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Re: Snug centre-pull hitch wanted
« Reply #7 on: February 26, 2021, 04:10:33 AM »
I apologize for the delay in testing the welcome suggestions from SS and DL.

I had already done the weeds inside my fence and was planning to nip over the fence to the overgrown periphery of the neighbouring farm to have a go at theirs (I didn't think they'd mind), but by a remarkable coincidence they hired a man with a terrifying tractor-mounted kind of robot chainsaw arm to run along the fence-line obliterating all vegetation.

Don't they realize people have knots to test?! So inconsiderate.

I'll see if I can find any they missed, or wait till more sprout (which believe me won't be long).

John