Author Topic: Fishing Knots - Joining Lines  (Read 30696 times)

knot4u

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Re: Fishing Knots - Joining Lines
« Reply #30 on: June 24, 2010, 08:12:55 PM »
In big thick rope, I have found that light comes through the Zeppelin Bend no matter how hard I pull.  The knot, nevertheless, still works great.
Do you also try to smash the collars tighter as you pull on the various ends of the bend?

I just tried on some nylon rope that's stiff and not even that thick.  Daylight still comes through a little, but I like that.  For this particular application, I will be untying the knot, and a tight bend is neither necessary nor desired.

roo

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Re: Fishing Knots - Joining Lines
« Reply #31 on: June 24, 2010, 08:21:34 PM »
I just tried on some nylon rope that's stiff and not even that thick.  Daylight still comes through a little, but I like that.  For this particular application, I will be untying the knot, and a tight bend is neither necessary nor desired.

Actually, if you fail to set it and leave the Zeppelin Bend too loose, there is a small but real chance that the bend may change forms into a jammable distortion with certain types of rope.

« Last Edit: June 24, 2010, 08:22:48 PM by roo »
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knot4u

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Re: Fishing Knots - Joining Lines
« Reply #32 on: June 24, 2010, 09:12:41 PM »
I just tried on some nylon rope that's stiff and not even that thick.  Daylight still comes through a little, but I like that.  For this particular application, I will be untying the knot, and a tight bend is neither necessary nor desired.

Actually, if you fail to set it and leave the Zeppelin Bend too loose, there is a small but real chance that the bend may change forms into a jammable distortion with certain types of rope.



I don't know what kind of rope and/or strength with which you're working.  No matter how tight I get the Zeppelin Bend, after the knot is dressed completely tight, when I then put a strong load on the standing ends, daylight ALWAYS comes through at least a tiny bit.  I have no problem with this.  Other bends, such as the Overhand Bend and many other bends, will not have daylight coming through when a strong load is placed on the standing ends.  It's just the nature of the various knots and doesn't seem to affect performance either way from what I can tell.
« Last Edit: June 24, 2010, 09:17:40 PM by knot4u »

roo

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Re: Fishing Knots - Joining Lines
« Reply #33 on: June 24, 2010, 09:16:44 PM »
I'm not really sure what kind of rope and/or strength with which you're working.  No matter how tight I get the Zeppelin Bend, after the knot is dressed completely, when I then put a strong load on the standing ends, daylight has ALWAYS come through at least a little. 
As long as you are setting it as you would other bends, you'll be fine.  It's the effort that counts.   I was just making sure you weren't being too lax. :)
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jcsampson

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Re: Fishing Knots - Joining Lines
« Reply #34 on: June 25, 2010, 12:01:32 AM »
Quote from: roo
"I would hope that you could eliminate daylight shining through gaps . . . in most cases."

I recommend also the adequate tightening of all knots on almost all occasions. My Zeppelin Bends are generally gap-free.

If I were to use big, twisted, polypropylene rope, then there might necessarily be gaps through which daylight can shine . . . but the knot will still be tight.

Quote
"Actually, if you fail to set it and leave the Zeppelin Bend too loose, there is a small but real chance that the bend may change forms into a jammable distortion with certain types of rope."

I recommend the adequate tightening of all knots on almost all occasions. Quite frankly, when folks talk about problems with the Bowline, all I can think is, "They probably didn't tighten it properly." If you don't tighten it properly, then you didn't make it properly, and you cannot expect it to work "as advertised."

JCS

Dan_Lehman

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Re: Fishing Knots - Joining Lines
« Reply #35 on: June 25, 2010, 06:16:48 AM »

Do you have a good idea of what that tiny squiggle shown in the cited
(and every other I've found) presentation is supposed to be -- you know,
the actual knot geometry that meets the Real World!?

I don't know what you're referring to.  It's been clear enough for me.  I'm sorry you're having problems.

If the cryptic images of the Uni knot are clear to you,
how can my question not be?  I even explained it:  that some
of the text implies that a (multi-)Strangle is expected, but it's
not something I've been able to coax out of one fishing line,
though did achieve it in a thinner one.  The commonly seen
images of the Uni Knot show as the last clear image (the final
being a mere "squiggle", in my words) is what one might
call a Reverse (multi-) Anchor Bend.

Quote
Quote
Please show me how to ring hitches can be used reasonably
qua end-2-end joints?!
The same way any hitch can be hitched to the belly of another hitch.
I'm not a regular user of the knot in question, but it certainly can be done.

I did say "reasonably"; theoretically I understand, and in this
case quickly dismiss as A Bad Thing.

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Transminator

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Re: Fishing Knots - Joining Lines
« Reply #36 on: June 25, 2010, 09:28:11 AM »

Bah!  It should be the case that such observations can be made
with confidence in at least some occasions.  In the one at hand,
you are right in re the Sheet bend vs. many other knots.

True, but I think we both agree that the proof of the pudding is in the eating.

???  Did you not read my post, in which the claim of supposed
strength of the Sheet bend was examined?!  --nothing "ok"
about it at all:  it is QUITE contrary ALL other evidence!  AND
contradicted by other information presented (by echo) on the site.
Moreover, for anyone familiar with knots it should be strikingly dubious
(along with your correct thinking about security).

I did read your post.
Whether the alleged percentages for breaking strength are correct or incorrect,
I can't tell and also have my doubts about them.
I was trying to point out though that retained breaking strength of one
knot may be high, it does not necessarily mean higher overall security of that knot.
In particular the sheet bend seems to slip before it breaks, but the zeppelin rather
breaks before it slips, at least in my experience.

Do you have a URLink for these tests?

Have a look here.
http://www.versus.com/fishing/videos/#browser (type: "knot wars" in the search bar)

They did not show a close up of the tied knot, but they showed how each knot is properly tied,
they tried it with 3 common types of fishing line and repeated each test several times.
They also seem to know what they are doing and you expect them to tie the knots they present correctly.
Do I have ultimate proof of that? No.

Those who might use such end-2-end knots in that case would do so
with Strangle knots tying off the ends; the main knot would be
chosen for ease of untying (and possibly for different-diameter ropes).

Does not make sense to me. 1. why not use a better knot in the first place (that has the quality of being secure AND ease of untying) like the zeppelin e.g. ?
2. If you use a sheet bend for ease of untying and then back it up with strangle knots (which jam so hard that a marlins pike runs home crying) the ease of untying is gone.

Except that in the "gel-spun" (HMPE) line, the Palomar isn't so strong;

Then I would use the uni instead of the Palomar, which is also good for that purpose.
« Last Edit: June 25, 2010, 12:09:25 PM by Transminator »

roo

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Re: Fishing Knots - Joining Lines
« Reply #37 on: June 25, 2010, 02:44:35 PM »
Quote
The same way any hitch can be hitched to the belly of another hitch.
I'm not a regular user of the knot in question, but it certainly can be done.

I did say "reasonably"; theoretically I understand, and in this
case quickly dismiss as A Bad Thing.
It's so unreasonable and bad because...?  Please be specific.

It's not going to be the strongest option (which is why I encourage common angling options), but it's tyable.  If he has another method of implementation that's stronger, all the better.
« Last Edit: June 30, 2010, 07:41:00 PM by roo »
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Dan_Lehman

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Re: Fishing Knots - Joining Lines
« Reply #38 on: June 25, 2010, 06:16:00 PM »
Whether the alleged percentages for breaking strength are correct or incorrect,
I can't tell and also have my doubts about them.
I was trying to point out though that retained breaking strength of one
knot may be high, it does not necessarily mean higher overall security of that knot.
In particular the sheet bend seems to slip before it breaks, but the zeppelin rather
breaks before it slips, at least in my experience.

In this case, I disagree:  we can tell -- the knots at issue are ancient,
and if they had anywhere near this alleged breaking strength we
wouldn't be learning about it all of a sudden only in the 21st century!
Moreover, one can't posit the knot as insecure and accept a high
breaking strength -- it has to hold in order to break.  And fishing
line does not make for greater, rather lesser, security.


Quote
Have a look here.
http://www.versus.com/fishing/videos/#browser (type: "knot wars" in the search bar)

They did not show a close up of the tied knot, but they showed how each knot is properly tied,
they tried it with 3 common types of fishing line and repeated each test several times.
They also seem to know what they are doing and you expect them to tie the knots they present correctly.
Do I have ultimate proof of that? No.

Thanks.  As for knowing what they're doing, well, hmmm,
that impression is given at times by some hilariously botched
presentations, but I'll hope that they do.

Quote
Those who might use such end-2-end knots in that case would do so
with Strangle knots tying off the ends; the main knot would be
chosen for ease of untying (and possibly for different-diameter ropes).

Does not make sense to me. 1. why not use a better knot in the first place (that has the quality of being secure AND ease of untying) like the zeppelin e.g. ?
2. If you use a sheet bend for ease of untying and then back it up with strangle knots (which jam so hard that a marlins pike runs home crying) the ease of untying is gone.

Your supposed "better" knot isn't proven to be all so secure
in the case of contact w/rock and wouldn't be trusted.
(Here is a good cue for Agent_Smith to re-surface and tell
of his further adventures at promoting that e2e joint to the
SAR/climbing world!).  And the Strangles would hardly be
so tight as you fear (!! --indeed, I've heard of folks having
them come loose, even (!?)), as they are only loaded by hand
in setting, and secure the Sheet bend's tails, that's all; ease
of untying is present.

Quote
Except that in the "gel-spun" (HMPE) line, the Palomar isn't so strong;

Then I would use the Uni instead of the Palomar, which is also good for that purpose.

Hmmm, I don't see the Uni in Geoff Wilson's small pamphlet on
tying Gel-spun lines; but I do see his note that the Blood knot broke
as such low loads (40%) that he stopped further testing/listing of it
in an appendix of various results:  the Uni seems rather like the
Blood in geometry.  And the bump in strength from the Palomar
to Triple P. of about 12%-pt.s came from the triple-turns on
the ring; he uses a similar thing with the Uni --although names
the structure "Collar & Capstan", and makes no comment about
it being tantamount to a Uni, and ties it directly into Strangle
form using a helper eye to pull tail up through wraps--
and boasts about an 85% or better strength.

It really is irritating to have authors present knots that are
--though not clearly stated, but by apparent presentation--
the same as others, but the similarity isn't remarked/confirmed!?
(Were it confirmed, the image from one knot could help in
guiding the tying of the other; it could further inform the reader.)

As I think Knot4U remarked, he'd never guess that the Palomar
would be so strong; I've had the same puzzlement, if not for
absolute strength, then, for relative strengths --i.e., I cannot
figure why one knot is stronger than this other, and so on,
given appearances.  Partly this must be due to the failure of
the presentation to show even the final image, or what the
geometry becomes on loading --though we can note that
with angling knots, one is often setting them to a fairly
high percentage of tensile strength (I think Barnes, who got
to test the new-fangled at that time nylon monofilament,
opined that about 60% tensile loading was needed for
optimal results):  which means that the set geometry
should be pretty near the at-rupture geometry.
(In contrast, we meager humans setting even skinny climbing
ropes come nowhere near to full-load force, let alone breaking
forces.)

Here's such a mystery:  an end-2-end joint recommended as
very strong, for gel-spun line, is joining two Bimini Twists
in a "Cat's Paw Splice" --which is just the repeated making
of a sort of "Girth hitch" around-&-through-&<repeat> weaving
of eye-&-eye.  With ten such interweavings, who would think
that the eyes would be where the break would occur?  --after all,
those eye strands individually need share only 50% of the force,
whereas the eyeknots have 100% on a single strand!  But, as
per Wilson, increasing from ten can gain strength, so it must be
in the wraps that the break occurs.  And this is at about 90%
of listed break strength (which is typically understated).

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Dan_Lehman

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Re: Fishing Knots - Joining Lines
« Reply #39 on: June 26, 2010, 06:19:36 AM »
I don't know what kind of rope and/or strength with which you're working.  No matter how tight I get the Zeppelin Bend, after the knot is dressed completely tight, when I then put a strong load on the standing ends, daylight ALWAYS comes through at least a tiny bit.

Yes, as the SParts press against the collars.  But I've just gotten
the knot to jam in 1/4" shock cord, and there's very little light
coming though.  Which I regard as a good thing; I'm not
sure how far I'd trust this jammed knot to stay tied, but it's looking
pretty good at the moment; I have no concerns about being able
to loosen & untie it --that will be simple enough.  I can get this
result by deliberate dressing of Ashley's Bend #1452, but that
knot is nowhere near so neatly compact is Rosendahl's.

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knot4u

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Re: Fishing Knots - Joining Lines
« Reply #40 on: June 29, 2010, 04:16:14 PM »
Please pass along the reports of slippage (sources, links).  

There are different modes of security.  The mode that tends to affect most knots in rope is shaking while the rope is slack, causing things to spring open (especially a problem in stiff, slippery rope).

According to this source, the security of the double fisherman fails in high strength, slippery cord.
http://www.xmission.com/~tmoyer/testing/High_Strength_Cord.pdf

"Dyneema/Spectra's very high lubricity leads to poor knot holding ability, and has led to the recommendation to use the triple fisherman's knot [rather than the traditional double fisherman's knot] in 6mm Dyneema core cord to avoid a particular failure mechanism of the double fisherman's, where first the sheath fails at the knot, then the core slips through."
http://en.wikipedia.org/wiki/Double_fisherman%27s_knot#Security

That wikipedia entry recommends the Triple Fisherman where the Double Fisherman fails.  I call B.S.  Where the Double Fisherman fails, I'd be going with an entirely different bend approach.
« Last Edit: June 29, 2010, 04:28:13 PM by knot4u »

roo

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Re: Fishing Knots - Joining Lines
« Reply #41 on: June 29, 2010, 04:34:41 PM »
According to this source, the security of the double fisherman fails in high strength, slippery cord.
http://www.xmission.com/~tmoyer/testing/High_Strength_Cord.pdf

"Dyneema/Spectra's very high lubricity leads to poor knot holding ability, and has led to the recommendation to use the triple fisherman's knot [rather than the traditional double fisherman's knot] in 6mm Dyneema core cord to avoid a particular failure mechanism of the double fisherman's, where first the sheath fails at the knot, then the core slips through."
http://en.wikipedia.org/wiki/Double_fisherman%27s_knot#Security

That wikipedia entry recommends the Triple Fisherman where the Double Fisherman fails.  I call B.S.  Where the Double Fisherman fails, I'd be going with an entirely different bend approach.
I think you may be misinterpreting strength findings.  Look at page 3:

For a double fisherman's knot, Gemini and Titan share an interesting failure mode.
The sheath breaks at the knot and the slippery core unties, pulling through the sheath. When a triple fisherman's
knot is tied, this does not happen. The strength gain for the triple fisherman's is not large, but it is enough to
change the mechanism.


The failure mode they're talking about is merely the mode of breaking with a small or "not large" strength change that one might expect anyway by using more rope.  This is not a security issue with slippage, it's what happens after the rope ruptures.

As I said before, the security issue with slick stiff rope and this knot is the possibility of things springing open, not slither or slipping.  
« Last Edit: June 29, 2010, 04:39:30 PM by roo »
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knot4u

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Re: Fishing Knots - Joining Lines
« Reply #42 on: June 29, 2010, 04:58:28 PM »
According to this source, the security of the double fisherman fails in high strength, slippery cord.
http://www.xmission.com/~tmoyer/testing/High_Strength_Cord.pdf

"Dyneema/Spectra's very high lubricity leads to poor knot holding ability, and has led to the recommendation to use the triple fisherman's knot [rather than the traditional double fisherman's knot] in 6mm Dyneema core cord to avoid a particular failure mechanism of the double fisherman's, where first the sheath fails at the knot, then the core slips through."
http://en.wikipedia.org/wiki/Double_fisherman%27s_knot#Security

That wikipedia entry recommends the Triple Fisherman where the Double Fisherman fails.  I call B.S.  Where the Double Fisherman fails, I'd be going with an entirely different bend approach.
I think you may be misinterpreting strength findings.  Look at page 3:

For a double fisherman's knot, Gemini and Titan share an interesting failure mode.
The sheath breaks at the knot and the slippery core unties, pulling through the sheath. When a triple fisherman's
knot is tied, this does not happen. The strength gain for the triple fisherman's is not large, but it is enough to
change the mechanism.


The failure mode they're talking about is merely the mode of breaking with a small or "not large" strength change that one might expect anyway by using more rope.  This is not a security issue with slippage, it's what happens after the rope ruptures.

As I said before, the security issue with slick stiff rope and this knot is the possibility of things springing open, not slither or slipping.  

I hear you, but a failure is a failure.  The technicalities don't matter to the user when it happens.  I have to wonder if the same failure would happen if a Zeppelin Bend were used in the same test.  That's the important question.

roo

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Re: Fishing Knots - Joining Lines
« Reply #43 on: June 29, 2010, 05:04:33 PM »
I hear you, but a failure is a failure.  The technicalities don't matter to the user when it happens.  I have to wonder if the same failure would happen if a Zeppelin Bend were used in the same test.  That's the important question.
I'm not sure why it would matter what happens after the rope ruptures if the overall strength is comparable to other knots.

When a knot breaks, it breaks.  I'm interested in what the strength percentage is, not what dance the rope does or does not do afterward.

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knot4u

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Re: Fishing Knots - Joining Lines
« Reply #44 on: June 29, 2010, 05:35:21 PM »
I hear you, but a failure is a failure.  The technicalities don't matter to the user when it happens.  I have to wonder if the same failure would happen if a Zeppelin Bend were used in the same test.  That's the important question.
I'm not sure why it would matter what happens after the rope ruptures if the overall strength is comparable to other knots.

When a knot breaks, it breaks.  I'm interested in what the strength percentage is, not what dance the rope does or does not do afterward.



It seems that that the Zeppelin Bend doesn't put as much stress on a rope as does the Double Fisherman.  The angles in the Zeppelin Bend are not as extreme.  So, perhaps the rope failure wouldn't happen in the first place.  I don't know, but again I'd be interested to know if the Zeppelin Bend would cause the rope to fail in the same manner.  I understand that you're not interested, and that's fine.  I am.
« Last Edit: June 29, 2010, 05:36:11 PM by knot4u »