Bowline Knot Re-threaded

Occasionally, we have mentioned the form of the Bowline where the
running end of the rope is on the outside of the loop (Dutch Bowline
(?)).

In the link, http://www.kong.it/lexis02.htm, posted by Ben, I was
surprised to see that, in the Harness Knot section, the "Bowline Knot
Re-threaded" (BKRT)was started with the "Dutch Bowline". I wondered
why.

Having tied the BKRT (carefully keeping ropes parallel), I noticed
that a load on the standing part squeezed (jammed, cinched) the final
loop of the running end. The knot was set. Starting with a regular
"Bowline", the final loop of the running end was not squeezed (jammed,
cinched) by a load on the standing part. Security, then, seems to be
the reason to start with the "Dutch Bowline".

I then tied the "Bowline on the Bight", ABOK #1080, where Ashley shows
the ends as equal. I noticed, that depending on the end you choose as
the standing part, you would end up with the BKRT or with the "other".

It seems to me, that if you used the method of tying the "Bowline on
the Bight" as a short cut to tying a "Bowline Knot Re-threaded", you
would have to be careful about how you started the loops.

Look forward to your comments - Brian.

Ps. this reminds me of posts on this newsgroup about the correct form
of the "Figure-of-Eight Loop". Hmmm . . . must find them again. - BG

(Brian Grimley) wrote in message . com...
Occasionally, we have mentioned the form of the Bowline where the
running end of the rope is on the outside of the loop (Dutch Bowline
(?)).
...
Ps. this reminds me of posts on this newsgroup about the correct form
of the "Figure-of-Eight Loop". Hmmm . . . must find them again. - BG

hi brian

I knew that the correct form of the "Figure-of-Eight Loop" is
mentioned in:

http://www.hse.gov.uk/research/crr_p...1/crr01364.pdf

but it is different than I expected :

"Unlike the double overhand and double figure-of-nine knots the rope
positions in the first bend do not appear to have a marked effect on
diminution of strength."

knot of help,

ben

("Dutch Bowline" is fine with me)

(ben) wrote in message news:

Occasionally, we have mentioned the form of the Bowline where the
running end of the rope is on the outside of the loop (Dutch Bowline?)

Aka "Left-handed Bwl", "Cowboy Bwl", and ... ?
(Wasn't it the Swedish Navy's preference?)

As for the remarks about starting one way or the other, I don't see that
as so important, as the "re-threading" can go a couple of ways, too, and
can achieve whichever end you want.

I'd prefer the end to repeat the "rabbit-goes-around-tree-back-into-hole"
collaring of the Spart vice pure tracing of the initial SPart loop.

As for tying the Dble-loop Bwl on a Bight for a shortcut, note that one
cannot do that AROUND an object (unless one has access to both ends, and
then it's not strictly "on a bight". This particular animal of issue is
a climber's tie-on loopknot.

[Ben]
Ps. this reminds me of posts on this newsgroup about the correct form
of the "Figure-of-Eight Loop".

I knew that the correct form of the "Figure-of-Eight Loop" is
mentioned in:

http://www.hse.gov.uk/research/crr_p...1/crr01364.pdf

For a much easier ref., see my image at:
http://www.iland.net/~jbritton/KnotP...ributions.html

(though there, yes, I opine for a particular loading of what I'll call the
"perfect form" (a symmetric form).

but it is different than I expected :

"Unlike the double overhand and double figure-of-nine knots the rope
positions in the first bend do not appear to have a marked effect on
diminution of strength."

I say that the jury's still out on this. I'm uncertain of Lyon's setting
of the knot. It's one thing to load all ends evenly, and another to load
in a more particular order. For supporting my opinion (an echo of that of
the Ontario Rock-Climbin Assoc.'s Safety Manual's assertion of 8-10% pt.s
stronger/weaker), I'd use my shown form and load the END & loop hard;
this sets the knot to bend the SPart favorably, it seems.

That said, on Tom Moyer's amazing 92% results, I learned that his forms
were apparently non-symmetric. He used two, and had interesting results:
overall, it was an even split (x to x+1 --odd # total); but per rope,
there were peculiar biases (4-1, 4-1, 1-4, 1-4, 3-2 !?).
And how much better than 90% can one even HOPE for, here?!!!
Well, we're both surprised by that figure. (Oh, THAT was for the Sterling
7mm nylon; the 4-1/1-4/3-2 were for the 5 hi-mod-fibre-cored cords.)

And, beyond this, we don't know where the breaks occurred. Lyon's report
is damn hard to figure, and I've not yet questioned them about it. I.p.,
though, note that their (limited) data on the knots. There's a note on
this posted elsewhere--to wit:

Lyon report (http://www.hse.gov.uk/research/crr_h...1/crr01364.htm)
and its assertion/conclusion about the relative strength of the
Overhand loop's two possible loadings; Lyon says:

"In all cases, failure occurs ... where the loaded rope first
rounds the loop. Whether it rounds the loop above or below
the loose end can affect strength by up to 10%. In the overhand
knot, it is stronger if the working rope lies above the rope end."

We can wonder what "above"/"below" mean, but a natural interpretation
would be that if the loaded part lies above the end, it bears against
it (rather than pulls away from it). We can also remark at "by up to 10%":
the natural interpretation in this context is "10 percentage points"
--something easily seen in result figures (as opposed to 66% vs.
60%, it would be 66 vs. 56). In any case, in the appendix with
test data, Lyon's wording is "live rope on {top/bottom} as it
entered the knot"--which I'd take to equate "top" with "above",
etc.. But in that case, their data if anything give a contrary
conclusion, with "on top" cases having a slight edge. Here's
their results, converted to percentages; they tested the loops
with knots on both ends, two specimens having the same of
whichever orientation (on top or on bottom), and the middle
case one of each(!). For the 3 low-elongation & 1 dynamic
ropes they got:
66-69-68 ; 64-60-66 ; 59-59-62 ; 59-59-63
Now, should we let this stand w/o question? I don't see
either the bias for the stated orientation (but there is some
dubious description in terms), and certainly don't see the
"10%" in any sure way! And with so few test cases, there
really isn't good ground to stand on in drawing conclusions.

--dl*
====

Dan Lehman wrote:

Occasionally, we have mentioned the form of the Bowline where the
running end of the rope is on the outside of the loop (Dutch Bowline?)

Aka "Left-handed Bwl", "Cowboy Bwl", and ... ?
(Wasn't it the Swedish Navy's preference?)

http://www.realknots.com/knots/sloops.htm names this knot as "Dutch
Marine Bowline" or as "Cowboy Bowline". It was interesting to see in
"Knotting Matters", June 2003, p.3, that the Bowline pictured in a
postage stamp from Sweden was a "Left-handed Bowline".

.... SNIP a discussion on strength ...

The "Bowline Knot Re-threaded" site was from the community of climbers
and cavers and the "Figure-of-Eight Loop" is a knot widely used by
them. It may be that of security, stability and strength of a knot,
stability is the most important characteristic for the two different
forms of the "Figure-of-Eight Loop" or for the two different forms of
the "Bowline Knot Re-threaded". I would suggest the "proper" forms
are more stable than the "other" forms.

For the sake of argument, I will say that, with the required
specifications on climbing rope and equipment, any force on a climber
that will break the above harness knots, in either of their two forms,
will kill the climber. In the climbing community: Stability Rules!!!

For Xmas, I would like to see tests that would put a number on
stability. I like Ashley's experiment in ABOK; but, I think it is only
a start. I wonder about its validity in the real world.

Brian.

Ps. I have used Richard M. Chisholm's definitions of security,
stability and strength that are found he
http://www.allaboutknots.com/termino...rformance.html . BG

(Brian Grimley) wrote in message . com...
...
Ps. I have used Richard M. Chisholm's definitions of security,
stability and strength that are found he
http://www.allaboutknots.com/termino...rformance.html . BG

hi Brian,

I agree, stability matters for safety systems, sailing,
hoists, animal husbandry etc
that is: the ability to keep shape under abnormal load/ circumstances
(yank, intermittend load, snagged tail, ring loading a loop etc)

strength matters (only?) for fishing and kites
that is: the resistance to breaking under excessive load
(rope dimensions intentionally too small for the task?)

Richard Chisholm his explanation about the breaking of a knot
kept me thinking (and a bit of testing) for a while.
how a knot is "dressed and set" seems to be a matter of importance
more than the proper form matters in a "figure of eight loop" and
"bowline rethreaded"
these are stable and strong loops when "dressed and set" properly

security matters anyway
that is: the prevention of slipping under normal load
can I say that security is all that matters for packaging, hanging,
building/pioneering ?

the papers of Richard M.Chisholm on knot terminology and performance
have learnt me understand knots more than learning knots itself.
and using knots has learnt me the most, so I agree with this statement
from another Chisholm: Mark Chisholm on treebuzz :
"If nothing else, I am a student of my stupidity.",

Ben

(ben) wrote:

Richard Chisholm his explanation about the breaking of a knot
kept me thinking (and a bit of testing) for a while.
...
the papers of Richard M.Chisholm on knot terminology and performance
have learnt me understand knots more than learning knots itself.

Glad to hear that his WWW site is alive again--it had been off-line when
I checked some years ago.
So, what does he have to say about this, what have you learnt?

(-;

(Dan Lehman) wrote in message . com...

...
So, what does he have to say about this, what have you learnt?

(-;


yes...

a post from Dan with a question (or two)
" what have you learnt? "
this is a joke / you are wondering?
I will try to answer anyway

Brian Grimley sent me the link a while ago
http://www.allaboutknots.com

it describes what words mean that you use Dan
like "nip" and "collar"
that helps understand your posts :+)



understand knots ... okay, I will try to explain

I know some knots and use a few
and I see things happening that I want to understand

what I read about knots, does not help me
many times it confuses, sometimes it is clearly wrong
and it does not explain what I see when knotting

some expect that a knot with gentle curves inside is likely to be stronger
or they explain that rope is squeezed by a knot until it breaks
or extra turns in a knot increase friction and therefore it is stronger

the knots that failed when I used them, did not break inside the knot
(actually, not the knot, but I failed using a proper knot or rope)
Richard M.Chisholm explains what I have seen myself
in "Why a Knot Breaks Just Outside the Nub"
I remember pictures from Murlle (in this newsgroup) that show the same

I stated:
"have learnt me understand knots more than learning knots itself"
learning is so many different things
for example :

(in order of understanding?)
trust a knot
know a knot by name
knot a knot by hart
read about knots
watch a knot fail
find a new knot
watch somebody using knots
solve a problem by using knots
teach a knot
draw a knot
destroy a knot
discuss a knot (in english)
reflect on my supidity
tell jokes about knots (not my competence)

in short: know-how on knots is not the same as know how to tie a knot

this post kept me busy for a while;
understanding myself is even harder than understanding knots,

ben

(Brian Grimley) wrote in message . com...
Occasionally, we have mentioned the form of the Bowline where the
running end of the rope is on the outside of the loop
(Dutch Bowline (?)).
...
Look forward to your comments - Brian.

Ps. this reminds me of posts on this newsgroup about the correct form
of the "Figure-of-Eight Loop". Hmmm . . . must find them again. - BG

hi Brian,

I presumed that particular groups use the dutch bowline as a cultural
difference
I could not find more on this, than everybody presuming Dutch navy
uses dutch bowline
and not even something to confirm it
I am sure that the Dutch bowline is not used by dutch scouts, or
sailors, or jachtsmen, or in the military

your observations made me try myself
is there a difference in behaviour between the bowline and the dutch
bowline?
are there more than traditional reasons to use a dutch bowline?

there might be
can anybody comment my explorations ?

when I tie a bowline and shake it to loosen the knot (or not tighten
it)
and then "ringload" the loop,
the tail slips out of the hitch
( "tail" and "hitch" as in:
http://www.allaboutknots.com/secuity_of_bowline.html )

it is disturbingly easy to do
but nothing surprising, just a known instability of the bowline loop
(ringload is: pull both legs of the loop in opposite directions)

when I repeat this with other forms of a bowline loop,
many slip easy when the knot is very loosely laid

the dutch bowline grips the slipping tail and tightens
( well, it tightened the times I tried )
it forms into a lapknot structure as in:
http://www.realknots.com/knots/sheetb.htm

the eskimo bowline holds a ringload, but not when loose
(as in http://en.wikipedia.org/wiki/Eskimo_bowline )
this seems to depend on the orientation of the free end too
a picture of a similar knot is sitka knot on:
http://www.earlham.edu/~peters/knotgrfx/gallery.htm

bowline on the bight or rethreaded bowline:
it slips easily when the load is not hanging from both loops together
(depending on what legs you load, even the tail can slip out ! )
I cannot reproduce Brian's observations on a difference between common
or dutch form as a start

a portugese bowline is even less stable than a common bowline
the same difference in stability of this bowline occurs between forms
with 'common' or 'dutch' orientation of its tail

by the way, to get an idea of this bowline:
http://131.230.57.1/knots/port_bl.htm
(but the recomendations are dangerous; do not use it as an "emergency
boswain's chair", since the loops aren't independent and this knot is
not stable, not even secure when used for a moving body)
the practical beauty and simplicity of a portugese bowline is:
you can first put a bight around an axle which is allmost out of reach
(or the doubled line through a hole, or both loops at once around a
load)
and then knot a standard bowline, hitching standing part and
loop/bight together
(without reaching under the car / load)

the bowline with double wraps around the tail tightens and holds ( ...
most of the time ?)
"double bowline" as in:
http://www.geocities.com/roo_two/doublebowline.html
the difference between common or dutch orientation of its tail is not
as distinct as in a simple bowline

by the way, this "double bowline" is the form I use more than other
forms; it is easy to tie allmost one handed
when I start with a small coil in one hand and put the free end
through that coil from behind
like the "one handed twist method", as shown at the bottom of:
http://www.iland.net/%7Ejbritton/bowline.htm#Twist
another start is: first use the (one handed) twist method and then add
an extra collar around the free end,
or just do the one handed twist method twice

soo, this post is way too long
but I run out of time; I do not have time to turn it into a shorter
one

in short:
there seems to be a difference in stability between the dutch oriented
bowline tail and the 'regular' bowline
so there might be more than traditional reasons to use a "dutch
bowline"

can anybody comment my explorations ?

disclaimers:
I like the bowline as "the knot to know"
this post is not intended as promotion for any bowline
it is based on some simple home made observations only
(in kernmantel climbing rope and in braided 'nylon' shoe laces)


knotting is an art (no pun intended),

Ben

"Every man takes the limits of his own field of vision for the limits
of the world." - Arthur Schopenhauer

Ben wrote:

I presumed that particular groups use the dutch bowline as a cultural
difference
I could not find more on this, than everybody presuming Dutch navy
uses dutch bowline
and not even something to confirm it
I am sure that the Dutch bowline is not used by dutch scouts, or
sailors, or jachtsmen, or in the military


Thanks for checking to see if that name was used in Holland (or should
I say, the Netherlands?). I seem to remember reading that the "Dutch
Bowline" was seen on the flat bottomed Dutch fishing boats, the ones
with leeboards used as drop keels (Hoy?). The "Dutch Bowline" was used
so that the excess rope (running end) could be coiled and supported by
the "Dutch Bowline". I have no reference for the above, and it could
be total nonsense!



the eskimo bowline holds a ringload, but not when loose
(as in http://en.wikipedia.org/wiki/Eskimo_bowline )
this seems to depend on the orientation of the free end too
a picture of a similar knot is sitka knot on:
http://www.earlham.edu/~peters/knotgrfx/gallery.htm


I would speculate that the "Eskimo Bowline" type loops do not belong
in the "Loop" category at all. I would speculate that they are really
binding knots. For example, I would site ABOK #1223, "Bathrobe Cord
Knot. Here, the "Eskimo Bowline" type knot, holds your bathrobe
closed.

The "Sheet Bend" in the "Eskimo Bowline" type knots seems to me to be
oriented to stop the loop itself from expanding (as in a binding). In
the regular "Bowline", the orientation of the "Sheet Bend", seems to
me to support a load on the standing part of the rope.

Although the "Eskimo Bowline" type knot may have been used as a loop
knot, I think this is incorrect. I think it evolved as a binding knot.

Please note that the above is written as speculation!

Brian.