Author Topic: Followthrough Double Overhand Knot  (Read 10787 times)

ddseddse

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Followthrough Double Overhand Knot
« on: March 14, 2008, 09:21:41 PM »
Just a regular double overhand knot followed through in the same way as you would a figure eight knot.

I just stumbled on this knot while playing around. I was wondering if anyone has heard of this knot before and if so, has it been used traditionally in one way or another. Do you know the strength and weaknesses of this knot?

Was just curious. Thanks.

turks head 54

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Re: Followthrough Double Overhand Knot
« Reply #1 on: March 14, 2008, 09:46:03 PM »
As an answer to your question:
The knot reduces the strength of your rope by 50%
and the knot jams. I'm not sure of the traditional uses.

TH54

Willeke

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Re: Followthrough Double Overhand Knot
« Reply #2 on: March 15, 2008, 08:34:27 AM »
I know the normal overhand knot followed through is called the water knot, it is used in webbing.
I do not see the need to double to overhand, as the fig 8 and the waterknot will fill most or all aplications, but then, I am not a practical knot tyer, I do mostly fance work.

Willeke
"Never underestimate what a simple person can do with clever tools,
nor what a clever person can do with simple tools." - Ian Fieggen

Writer of A booklet on lanyards, available from IGKT supplies.

Fairlead

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Re: Followthrough Double Overhand Knot
« Reply #3 on: March 15, 2008, 10:57:01 AM »
IF -
You mean that a Double Overhand Knot is followed through from end to standing part with another (similar) line in the manner of tying one of the Figure of Eight Bends; then the answer is in Ashley's Book of Knots
#1427 Double Twofold Overhand Bend.  Ashley relates it to the Matthew Walker Knot and used mainly for Ornamental Purposes.

TH54 - What criteria did you use to ascertain the 50% reduction in strength of the rope with this knot?

Gordon

turks head 54

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Re: Followthrough Double Overhand Knot
« Reply #4 on: March 16, 2008, 12:05:24 AM »
The 50% strength came from a mountain climbing document that I have read.
I will try an find the document.

Th54

Dan_Lehman

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Re: Followthrough Double Overhand Knot
« Reply #5 on: March 16, 2008, 08:00:18 PM »
As Fairlead questions, you don't give enough information re the knot:
are you joining two ropes, or making an eye?  In any case, both such
knots are known and used, in angling at least (including giving the
knot one more twist); the bend (ends-joining) is known to anglers as
the Surgeon's Knot, and claimed to be nearly 100% if tied correctly
in not-too-strong (<60*#) line (which enables hand setting).  It should
be noted that anglers don't tie the knot in the "follow-through" method,
which is tedious, but in the in-the-bight manner; this is so for the
bend, as what is joined is a short piece to a long one, so the short
one's end is accessible.  (Ashley's tying method seems especially
problematic, re dressing!)

Quote
As an answer to your question:  The knot reduces the strength of your rope by 50%  ... I read this <somewhere>

It's discouraging to see such a remark from someone well read on this forum.
We have I'd hoped shown the weakness of rumors of knot strength, from the
perspective of not knowing exact geometries, or test method, or materials.
And from a single (dubious?) source.
And as noted here, it's not even clear what knot is at issue!
AND, as with any "followed through" knot, there's the question of which end is
loaded (or, how the knot's oriented).

For a loopknot in material similar to climbing rope, I expect that the knot has
reasonable strength (~= 65..70%).  I think that the bend will be weaker in such
cases, unless somehow one can bring greater-than-manual force to setting it.

--dl*
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Stoatstail

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Re: Followthrough Double Overhand Knot
« Reply #6 on: March 17, 2008, 11:46:31 PM »
Most commonly known as double or triple turn surgeons knots in angling circles.

Forgive the ignorance of a novice Dan but what is the difference between the "tedious" in the bight manner, which I suspect I use, and the follow through method ?

Despite , no doubt, being a very very dubious source, I tested this knot as a bend in 10kg mono to ISO2062:1995 and got about 65% as I recall, I did the same with a Bimini Twist last year and had over 90% for a 20 turn knot.

Angling writers regularly "discover" 100% knots.... it helps them to sell copy.......   :)


Dan_Lehman

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Re: Followthrough Double Overhand Knot
« Reply #7 on: March 18, 2008, 07:35:37 PM »
Forgive the ignorance of a novice Dan but what is the difference between the "tedious" in the bight manner,
which I suspect I use, and the follow through method ?
Whoa, you mis-read; I wrote:  'anglers don't tie the knot in the "follow-through" method,
which is tedious, but ...'
.  In either case, I don't think it's ever been clearly presented as
to how to orient/dress the knot.  This might explain your test result being less than what
Sosin & Kreh assert.

Quote
Angling writers regularly "discover" 100% knots.... it helps them to sell copy.......   :)

It also comes from using vendor's nominal "tensile" strengths, which are often
understated, to give them better-looking results.  Elsewhere in this forum I cited
some articles by Doug Olander in which he more carefully tested both knots and
lines, and found some amazing differences in both stated vs. actual line strengths
and knot strengths (i.e., that a knot had quite different "efficiencies" per line).

Btw, Bill Nash seems to be pretty attentive to angling knotting and has his info
at  hometown.aol.com/billsknots/  (but I've yet to indulge).

--dl*
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Fairlead

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Re: Followthrough Double Overhand Knot
« Reply #8 on: March 18, 2008, 08:45:29 PM »
I tried tying this (assuming a double overhand knot in the end of one line) as in ABOK 1427 and as Dan says it is somewhat tedious - however if you tie the double overhand then pull it gently into the stage where it looks like it was tied by the grapevine method (the loop/belly starts to wrap around the tucks), then follow the  end through with the second line to the standing part, it pulls up into a very neat bend.

Gordon

Stoatstail

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Re: Followthrough Double Overhand Knot
« Reply #9 on: March 18, 2008, 11:16:46 PM »
Quote
Whoa, you mis-read; I wrote:  'anglers don't tie the knot in the "follow-through" method,
which is tedious, but ...' .  In either case, I don't think it's ever been clearly presented as
to how to orient/dress the knot.

Dan, I genuinely dont know the difference even though I must have tied this knot thousands of times...I'm on a very low horse, believe me :)

Quote
It also comes from using vendor's nominal "tensile" strengths, which are often
understated, to give them better-looking results.  Elsewhere in this forum I cited
some articles by Doug Olander in which he more carefully tested both knots and
lines, and found some amazing differences in both stated vs. actual line strengths
and knot strengths (i.e., that a knot had quite different "efficiencies" per line).

This is unquestionably true in heavier duty mono though in very light lines manufacturers tend to overstate the strength. There is a set of running test results based on ISO 2062 run by the http://www.eftta.com/english/line_testing.html?cart=12058772461365916eftta. Doug Olanders test results on the bimini were very odd indeed and seemed to suggest that tying a 12 turn bimini actually increased the tensile strength of some lines, how far up the line this remarkable property extended he didnt say. :)
Very few of the authoritative voices on angling knots test to a consistent standard and even the IGFA, the record awarding body in the US, admit that they dont have consistent protocols.

Bill Nash, unfortunately, died a couple of weeks ago. He was a very nice man and despite regular claims, alongside the above mentioned Lefty Kreh, of 100% knot strength he was perfectly prepared to privately admit that very few knot tiers in the angling community could dress a knot well enough to get anywhere close.   

Dan_Lehman

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Re: Followthrough Double Overhand Knot
« Reply #10 on: March 19, 2008, 06:20:15 PM »
Quote
Whoa, you mis-read; I wrote:  'anglers don't tie the knot in the "follow-through" method,
which is tedious, but ...' .  In either case, I don't think it's ever been clearly presented as
to how to orient/dress the knot.

Dan, I genuinely dont know the difference even though I must have tied this knot thousands of times

The difference is this:  in the "re-threaded/re-woven" method, one ties a knot in
single strand, then brings the end back into the knot by tracing a part (usually the
end's exit--making a u-turn forming the eye)--which is necessary, e.g., for tying
a rope onto one's climbing harness closed loops--;
in the "in (better:  with) - the - bight" method, one doubles the line (i.e., makes
a (longish, usually) bight), and then ties the knot (two ends together, bight-end
opposite, for the eye).  With these knots, both ways call for some attention to
dressing, which is seldom specified (how, that is).
And I should remark that one can see how much more easily the Fig.9 loopknot
is formed, with the bight, as one can make the initial turn tight, having only to
reeve the bight end through the first-formed loop rather than through that AND
the overwrap turn of the Dbl.Overhand.  And this too is an angling knot, sometimes
put as a variation of the Fig.8.

Re-weaving w/the springy monofilament would be esp. difficult.

Quote
Bill Nash, unfortunately, died a couple of weeks ago. He was a very nice man and despite regular claims, alongside the above mentioned Lefty Kreh, of 100% knot strength he was perfectly prepared to privately admit that very few knot tiers in the angling community could dress a knot well enough to get anywhere close.

Oh dear, what a loss.
I will hope that remaining of his stock of books/CDs/video are yet available;
it was a "meaning to do" purchase yet undone, for me.  Are you familiar with them?
 :-\

Stoatstail

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Re: Followthrough Double Overhand Knot
« Reply #11 on: March 20, 2008, 10:15:24 PM »
I didn't buy his book but I'm sure it will still be available and, now you mention it, I think I will.
He was diligent with his correspondence with we lesser mortals and I had a number of entertaining e-mail tangles on the subject of knot strengths, always with good humour,..... nice guy. :(