Author Topic: Evil Impostors for the Butterfly Bend  (Read 7173 times)

roo

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Evil Impostors for the Butterfly Bend
« on: June 30, 2010, 05:10:34 AM »
This subject came up recently for the Ashley Bend:

http://igkt.net/sm/index.php?topic=1885.0

...but the same evil impostor just happens to pass for a Butterfly Bend as well.  It may be a lesser risk, depending on your skill, but I mention it here:

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

I remember reading a paper where the Butterfly Bend was pulled from the running of tests because this evil impostor issue was discovered, but I'm not sure if they were thinking of the same impostor, and my e-mails to the organization that produced the paper are getting bumped back.

Are there other impostors for this bend that could be tied in error?

« Last Edit: June 30, 2010, 05:34:42 PM by roo »
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dmacdd

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Re: Evil Impostors for the Butterfly Bend
« Reply #1 on: June 30, 2010, 09:11:41 PM »

... the ... evil impostor [ABOK 1408/1409 posing as Ashley's bend] jjust happens to pass for a Butterfly Bend as well.  It may be a lesser risk, depending on your skill, but I mention it here:

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


ABOK 1408/1409 certainly looks like the Butterfly bend. It looks more like the Butterfly bend than it looks like Ashley's bend, 1452. But, without having studied the question carefully, I doubt that the common methods of tying the Butterfly bend are prone to a simple  error that would generate 1408/1409. The most common convenient method of tying 1452, the method by which Ashley's bend is commonly taught, which is not shown in your note on the BB, and is shown here:
http://davidmdelaney.com/ashley-bend/ashley-bend.html
is, on the other hand, catastrophically vulnerable to a simple error that generates 1408/1409.

This is especially worrying because 1408/1409 is easier to dress than 1452, and is prettier when dressed.  Someone making the error might well be drawn by this convenience and this aesthetic judgement into believing that 1408/1409 must be the famous Ashley's bend.  I know this is so because it happened to me, until I came to suspect I had invented an "improvement" on 1452, a suspicion you dismissed in rec.crafts.knots.

Can anyone show how a  simple error in e.g. the methods for the BB shown in
http://davidmdelaney.com/alpine-butterfly-bend/Alpine-butterfly-bend.html
can generate 1408/1409?

Whether or not this challenge  with respect to the BB can be met, Ashley's bend. at least,  is certainly shown in a jaundiced light by its vulnerability to this error. One wonders if this Guild should issue a deprecation of it, or at least a formal recommendation of some kind that the vulnerability should also be taught, or that the error should be precluded by the motions taught, as in
http://davidmdelaney.com/ashley-bend/ashley-bosun-method.html


roo

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Re: Evil Impostors for the Butterfly Bend
« Reply #2 on: June 30, 2010, 09:59:21 PM »
ABOK 1408/1409 certainly looks like the Butterfly bend. It looks more like the Butterfly bend than it looks like Ashley's bend, 1452.
I kinda had the opposite impression.  Mimicry is in the eye of the beholder, I guess.

Quote
But, without having studied the question carefully, I doubt that the common methods of tying the Butterfly bend are prone to a simple  error that would generate 1408/1409.
I don't think it's a huge danger, no.  I could understand it happening, especially if the rope was stiff enough to have a mind of its own, or if the rope gets tossled by some obstacle during tying, or if the rope length used is excessive and sloppy and the tyer isn't paying close enough attention.

Quote
The most common convenient method of tying 1452, the method by which Ashley's bend is commonly taught, which is not shown in your note on the BB, and is shown here:
http://davidmdelaney.com/ashley-bend/ashley-bend.html
is, on the other hand, catastrophically vulnerable to a simple error that generates 1408/1409.
Do you mean the interlinked b&q shapes?  I see them in both places, if you mean by "note" the Notable Knot Index entry above.  Maybe "note" refers to this thread?

Quote
This is especially worrying because 1408/1409 is easier to dress than 1452, and is prettier when dressed.
And because the 1409 may seem easier to part after heavy load.

Quote
Can anyone show how a  simple error in e.g. the methods for the BB shown in
http://davidmdelaney.com/alpine-butterfly-bend/Alpine-butterfly-bend.html
can generate 1408/1409?
For the methods that try to replicate the loop method, at perhaps some expense of ease of execution, that risk would likely be eliminated.  I'll note that the "hybrid method" shown in another thread is prone to getting a half-hitch loop-as-a-bend imposter.

The locking elbows methods are going to have a possible 1409 error by a lapse of attention in forming the "p" shape, for example, allowing the free end to point left/out.

Quote
Whether or not this challenge  with respect to the BB can be met, Ashley's bend. at least,  is certainly shown in a jaundiced light by its vulnerability to this error. One wonders if this Guild should issue a deprecation of it, or at least a formal recommendation of some kind that the vulnerability should also be taught, or that the error should be precluded by the motions taught, as in
http://davidmdelaney.com/ashley-bend/ashley-bosun-method.html
Are you thinking of a note on their website?  Right now, I don't think it's a big danger, as the 1452 doesn't see much use, but some notation wouldn't hurt.  If Ashley's depiction of 1408/1409 was simplified in his book, it probably would have been noticed right away (not that I'm blaming him).  

I'll have to get back to you on your alternate method.


« Last Edit: June 30, 2010, 10:30:11 PM by roo »
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roo

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Re: Evil Impostors for the Butterfly Bend
« Reply #3 on: June 30, 2010, 10:56:48 PM »
I'll have to get back to you on your alternate method [for the Ashley Bend].
After giving it a go for a while, I think the method may be a bit intimidating to execute from memory for a good portion of folks.  It does look like it helps eliminate the 1409 risk as I try permutations.

A problem with relying on alternative methods is that if people use the bend, they may decide that they prefer a more basic method, without realizing the possible hazards involved.  They may find that basic method via an old book, a website, or even by reverse-engineering the knot on their own.
« Last Edit: June 30, 2010, 11:44:52 PM by roo »
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jcsampson

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Re: Evil Impostors for the Butterfly Bend
« Reply #4 on: June 30, 2010, 11:49:11 PM »
Quote from: dmacdd
"ABOK 1408/1409 certainly looks like the Butterfly bend."

Say that again?

Whatever results from a failed attempt at tying the Butterfly Bend will likely look like something distinct enough from the Butterfly Bend.

Quote
"One wonders if this Guild should issue a deprecation of [the Ashley Bend], or at least a formal recommendation of some kind that the vulnerability [for a potential mistake in its making] should also be taught, or that the error should be precluded by the motions taught, as in
http://davidmdelaney.com/ashley-bend/ashley-bosun-method.html [.]"

Regarding the Ashley Bend, there is no cause for alarm:

An excellent mnemonic aid exists, which, if adequately propagated by the responsible, can prevent the improper tying of the Ashley Bend, by any tyer, regardless of the tyer's knotting experience or mental prowess:

Left goes UNDER, right goes in from UNDER, right goes UNDER. . . .

"UNDER, UNDER, UNDER for the ASHLEY, ASHLEY, ASHLEY!"

Repeat after me:

"UNDER, UNDER, UNDER for the ASHLEY, ASHLEY, ASHLEY!"

Now, let's have a sing-along:

"UNDER, UNDER, UNDER for the ASHLEY, ASHLEY, ASHLEY!"

Further, along with the above, and instead of propagating the idea that the Ashley Bend is a bad bend because it could be mistied, the responsible can propagate the knowledge that the ABOK #1408 and #1409 knots immediately FAIL to show the characteristic internal crossings of the Ashley Bend (which the Ashley Bend of course does immediately show upon tightening).

"UNDER, UNDER, UNDER for the ASHLEY, ASHLEY, ASHLEY!"

"And if you ever attempt to tie an Ashley Bend, and it immediately fails to show the characteristic internal crossings of the Ashley Bend, then untie it and try again."

JCS

jcsampson

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Re: Evil Impostors for the Butterfly Bend
« Reply #5 on: July 01, 2010, 12:09:46 AM »
Let's say you attempt to make a Butterfly Bend, but because you're out-of-touch with the Butterfly Bend, you try to make it this way:

Left goes over, right goes in from the bottom, and then--instead of making a d that goes over--you make a q that goes over. . . .

In this case, you wind up with an ABOK #1408 or #1409.

But how could anyone mistake that for a Butterfly Bend? Simply because it has its tails coming out on the same side?

It is precisely the "diagonal lopsidedness" (of which I have spoken in other threads) of ABOK #1408 that saves the day and makes it clear to the knotter that it's not a Butterfly Bend.

JCS

roo

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Re: Evil Impostors for the Butterfly Bend
« Reply #6 on: July 01, 2010, 12:20:10 AM »
But how could anyone mistake that for a Butterfly Bend? Simply because it has its tails coming out on the same side?

It is precisely the "diagonal lopsidedness" (of which I have spoken in other threads) of ABOK #1408 that saves the day and makes it clear to the knotter that it's not a Butterfly Bend.
I'm glad you have such instant and precise bend recognition prowess, but few will be able to match your abilities.   Many would see tails coming out the one side, two collars, a compact form, and yes that would be close enough to what they were expecting to get.   I could very well understand them not giving it a second look.

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roo

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Re: Evil Impostors for the Butterfly Bend
« Reply #7 on: July 01, 2010, 12:38:59 AM »
Regarding the Ashley Bend, there is no cause for alarm:

An excellent mnemonic aid exists, which, if adequately propagated by the responsible, can prevent the improper tying of the Ashley Bend, by any tyer, regardless of the tyer's knotting experience or mental prowess:

Left goes UNDER, right goes in from UNDER, right goes UNDER. . . .

"UNDER, UNDER, UNDER for the ASHLEY, ASHLEY, ASHLEY!"
You're assuming propagation.  You assume too much.  This isn't in most sources and won't be changed.  Even assuming everyone knows this jingle, suppose someone goes "under", but under the wrong part of rope, making it an "over".  Suppose people get so accustomed to tying the bend, that they drop the singing from their mental process and eventually go "over".  Some people may just have a lapse simply because they're thinking of something else at the time.

Quote
...the responsible can propagate the knowledge that the ABOK #1408 and #1409 knots immediately FAIL to show the characteristic internal crossings of the Ashley Bend (which the Ashley Bend of course does immediately show upon tightening).
This may be OK in front of a book showing every detail of the bend when you're told to check the "internal crossings", but not out in the field where people might take a quick look to see if they get about what they were expecting.
« Last Edit: July 01, 2010, 03:40:38 AM by roo »
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jcsampson

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Re: Evil Impostors for the Butterfly Bend
« Reply #8 on: July 01, 2010, 12:44:46 AM »
Propagating new information that can help to solve knotting problems sounds like a job for . . . the IGKT.

There is a simple idea that can be propagated to solve this problem:

"Owing to the possibility of incorrect tying and the dangers that it could present, it is highly recommended that all knotters select a single favorite bend, practice it regularly, and restrict themselves to the use of just that one favorite."

But, don't you think that this would simultaneously solve one problem and create another?

The final solution, then, would be to encourage all knotters to learn and stay in touch with all popular bends.

JCS

dmacdd

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Re: Evil Impostors for the Butterfly Bend
« Reply #9 on: July 01, 2010, 05:27:12 PM »
quote]The most common convenient method of tying 1452, the method by which Ashley's bend is commonly taught, which is not shown in your note on the BB, and is shown here:
http://davidmdelaney.com/ashley-bend/ashley-bend.html
is, on the other hand, catastrophically vulnerable to a simple error that generates 1408/1409.
Do you mean the interlinked b&q shapes?  I see them in both places, if you mean by "note" the Notable Knot Index entry above.  Maybe "note" refers to this thread?

[/quote]

No, I meant one particular arrangement of the interlocked shapes, before the working ends have been tucked to create the interlocked overhand knots, the one in which the standing parts are vertical, the loops are at the top, and the working ends extend to the left.  This is the one I have seen on a US scouts web site, on a T shirt, in Wikipedia, and in forgotten knot books. It seems to have become iconic.

The crucial error may be seen most graphically (i.e. being made) in
http://davidmdelaney.com/ashley-bend/ashley-lubber-method.html

roo

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Re: Evil Impostors for the Butterfly Bend
« Reply #10 on: July 02, 2010, 05:40:53 PM »
What about the half-hitch loop (see attached image of loop) tied as a bend? The loop form is wrongly called the butterfly loop on rare occasion.  It's certainly malignant, as it's not very secure or stable.

As a bend, this seems less likely of an error than the ABOK 1408/1409.  Leaving the ropes non-interlinked in the first step seems very much counter to people's natural inclinations, and not just a confusion of the way rope ends go.  That could be just my mindset.  Alternative tying methods may provide a way to make this error more likely, such as a recently described "hybrid method" for the loop (http://igkt.net/sm/index.php?topic=1259.0). Let's go to the next step:

Tied as a loop, pulling on the loop, the imposter knot form can easily keep its appearance.  Tied as a bend, pulling the standing parts tighter often causes things to slide open noticeably.  But if the free ends are pulled first, that's less likely to happen.

Overall it seems like a less likely candidate for the Butterfly Bend's evil impostor.  Maybe someone knows of other easy ways of tying this mistake as a bend.
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