Author Topic: Which form of Carrick bend?  (Read 5553 times)

R Statistician

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Which form of Carrick bend?
« on: June 08, 2013, 09:19:54 PM »
In Pawson's Visual Guide (2012) the Carrick bend has the free ends on the same side (see photo #4), but Ashley's security tests indicate that the diagonal form is more secure.  Is the non-diagonal form preferred on the basis of some other criterion (such as break strength or jamming)? 

By the way, the instructions for the Stevedore knot (page 47) don't produce the knot shown at the top of page 47.  I believe that the photo is the Stevedore knot, but the instructions produce a different stopper knot (the intermediate stopper knot).

roo

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Re: Which form of Carrick bend?
« Reply #1 on: June 08, 2013, 09:42:27 PM »
In Pawson's Visual Guide (2012) the Carrick bend has the free ends on the same side (see photo #4), but Ashley's security tests indicate that the diagonal form is more secure.  Is the non-diagonal form preferred on the basis of some other criterion (such as break strength or jamming)? 

The mediocre security of the Carrick Bend diminishes substantially when the form is changed as you mentioned.  With some Bluewater II rope and short tails, the standard Carrick Bend fell apart after about 26 shakes.  The other form only took 4 shakes.

The Carrick Bend doesn't jam to start out with, so there's no justification for a different form there.  Break strength usually doesn't come up with rope as it's usually poor practice to be using rope with loads levels that risk rupture. 
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Dan_Lehman

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Re: Which form of Carrick bend?
« Reply #2 on: June 09, 2013, 05:14:41 PM »
Welcome back, R-Statistician!
(Even though only your debut post precedes this,
and was 4 years prior, you are remembered.   :)  )

I do not have access to the Pawson(-named) document
that you cite, but do have two earlier works under his
name.  I mention "name" in consideration that, for
whatever reason, there might be separation from the
contribution of the author with the illustrations in the
book --often to poor result, or otherwise (not so) surprising
result.  ("Don't these guys even TIE their knots?!" I'm
inclined to wonder, at times.)

Both The Handbook of Knots & Pocket Guide to Knots & Splices
show the (more) secure form of the carrick bend.  The
first(-published) is not explicit about the position of the
tails; it contains the curious instruction to "pull on all
four ends to tighten the knot" --huh? (eariler it says
that the knot can collapse when loaded).  The latter
work expressly advises that tails should be "opposite
on another and not too short, as the [end-2-end knot]
will collapse when put under strain."  This is frightenly
shy of decent knot advice : one SETS the knot into
form, preferably, not hoping for favorable capsizing!
(And, as has been presented in the IGKT's Knotting
Matters
(by P.vdGriend) and briefly filmed on the t.v.
show "The Deadliest Catch" (to my eye), the knot is tied
by another method that doesn't entail capsizing.)

As for the stevedore knot, that is shown correctly in the
former work and isn't in the latter.  I surmise that what
you describe as the mistake is a like knot with one fewer
(half-)turn --what rockclimbers might call a "fig.9" knot;
this is a not uncommon mistake seen in knots books.


--dl*
====

ps : Hoping that you're beyond that old (back then!) computer
system, and so able to help to keep our musings tamed in
statistical implications.

 ;)

[Inkanyezi] gone

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Re: Which form of Carrick bend?
« Reply #3 on: July 13, 2013, 11:11:52 PM »
Pulling on all four ends is easily applied by sitting on your hind part, gripping the two standing parts with the fingers of your lower hands, and holding the "working ends" with your upper hands. It does not however draw the Carrick Bend up into proper shape, even if you're shaped as an ape. It is in fact much simpler, although many people have a difficulty to fathom that you do more or less the opposite of what you might think is correct.

So, the ends are best left to their own devices, as the knot is drawn up by pulling on both standing parts. If you think you should touch the ends, to diminish the initial slip, just grab them both together when load is applied to the knot. Do not pull on the ends!

The final form is easier accomplished when the knot is turned so that the ends hang down freely by themselves. So when tying in large stuff, the standing parts should be on top and the ends below the knot. 

And the only form of the Carrick Bend worth its salt is the diagonally opposite pattern.

I have a webpage that describes it here:
http://web.comhem.se/~u77479609/Carrick%20Bend.html

And there is a PDF here:
http://web.comhem.se/~u77479609/Carrick_Bend.pdf

I even made a video long ago to show how I tie it:
http://www.youtube.com/watch?v=wTmwqYQI93Y

You pull on the standing parts to draw up the knot. Just jerk them apart!


The final form of the knot is two interlocking backhand knots.
« Last Edit: July 14, 2013, 09:10:12 AM by Inkanyezi »
All images and text of mine published on the IGKT site is licensed according to a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
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Stagehand

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Re: Which form of Carrick bend?
« Reply #4 on: July 14, 2013, 07:48:15 PM »
Inkanyezi, thank you for your remarks and your work.  I am glad to encourage your suggestion to leave the ends alone in tying Carrick Bend (diagonally opposite pattern).  I see the importance of your remarks in showing how Carrick Bend works differently than many other knots.  Its patterning takes better advantage of knot crossings by following a polyhedral graph (Rolfsen 9_40).  Once the ends are near completing this pattern as the ends of Carrick Bend are, it can be evident just how effective knot crossings can be in such a knot.  The Carrick Bend is seen as secure before it is set with frictional forces. 
This confidence in the integrity of the Carrick Bend can be expanded in several ways.  1) Other polyhedral graphs provide other knots that have similar dependable behaviors.  Carrick Mat (Rolfsen 8_18)  provides various dependable knots.  2) Knots patterned after polyhedral graphs are made effectively more secure by continuing into the pattern.  Even Carrick Bend could be more secure by continuing the ends correctly.  3) Carrick Bend as much as it represents a larger polyhedral graph also suggests other uses.  If the ends of Carrick Bend are joined and one standing line is freed, this makes a good fixed loop.

knot4u

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Re: Which form of Carrick bend?
« Reply #5 on: July 14, 2013, 10:13:04 PM »
The final form of the knot is two interlocking backhand knots.


I find it beneficial to pull the ends a little bit after the Carrick Bend reaches this level of dressing.

Dan_Lehman

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Re: Which form of Carrick bend?
« Reply #6 on: July 16, 2013, 05:29:07 AM »
The final form of the knot is two interlocking backhand knots.

I find it beneficial to pull the ends a little bit after the Carrick Bend reaches this level of dressing.
And the benefit being ... ?
I think your point could be that without the pulling,
the tails will be prone to being drawn by the SParts
away from the center, into a less secure state
(and maybe leaving the U-turns of the SParts
as mere 1-diameter turns, weakening the knot).
This careful setting gets problematic with different
rope natures (diameter, construction, flexibility).
(I do not know if the Alaskan crabber who have been
said/seen to extend pot warps with this knot will
bind the tails with electrical tape; I suspect that they
do.)

And I find it beneficial to re-tuck the tails through the
interlocked SPart turns to obtain the interlocked-overhands
knot Ashley's bend #1408 !  (Or to re-tuck them
and get Harry Asher's "shakehands bend" (cf. #1031).
Both of these make fine eyeknots as well,
with the latter being TIB to boot.

With variations on this theme, one can discover the
superior Ashely's bend #1452 & #1453 as well.

And if one is fortunate enough to seek such benefits
with the inferior version of the carrick bend, one
will be rewarded with the superior Ashley's #1452!


--dl*
====
« Last Edit: July 16, 2013, 06:12:15 AM by Dan_Lehman »