Geometric definition of a Bowline

[Dennis Pence]

I am just suggesting a minor edit of your definition.  I feel that the repeated use of the word "loop" leads to much confusion about what is essential.

A fixed eye knot will be considered in the Bowline Family if it satisfies the following criteria, namely that it has a nipping part and a collar that have the following properties.

Nipping part
1. It is TWATE (Tiable without access to an end).
2. It is based on a helix - being circular in shape or circularised.
3. It is loaded at both ends.
4. It encircles and clamps both legs of the collar.
5. It is functional (clamping force of a nipping part increases in direct proportion to load).

Collar
1. It performs a U turn around the S.Part
2. It is braced upon the S.Part
3. The S.Part has a stabilising effect on the collar
4. There are two legs of the collar
5. Both legs of the collar pass through the nipping part.
6. Both legs enter the nipping part from the same side.

If a fixed eye knot fails one or two of these criteria, then we may call it a Quasi-Bowline.

I accept that the Karash Single Loop Knot (crossing hitch) fails criteria 2 for the nipping part.  But I also think that the Girth Hitch fails that same criteria.  I also think that the eye knot diagramed in reply 13 based upon #1435 meets all of these criteria, even though it is a little harder to tie than a Round Turn Bowline #1013.  I also think there is going to be a pretty long list of Quasi-Bowlines.

[agent_smith]

per Dennis Pence:

I feel that the repeated use of the word "loop" leads to much confusion about what is essential.

Is your confusion universal - ie everywhere and across all cultures?
Or is the confusion limited and confined only to yourself and/or
possibly a small cohort of individuals?

If you rely upon and require Ashley to find truth and meaning (your epistemology),
this might explain your confusion.
Ashley did not have clear and unambiguous definitions of what a loop, turn, and
half hitch is. Ashley published his book in 1944 - and we are now at 2025.
It is not unreasonable to surmise that our technological understanding has advanced
since 1944.

If Ashley is not your primary source of truth and meaning, then something else
must explain your confusion.

The word loop is found in the English language.
The ordinary dictionary meaning of loop (in the context of rope, line, twine):
Def: A circular shape formed when a line curves around and crosses itself.
A loop has chirality (either 'S' or 'Z').
This is in contrast to the 'eye' of an 'eye knot'. The 'eye' of an 'eye knot' has
no chirality. An 'eye' is not a 'loop'.
A loop is 'TWATE' (Tiable Without Access To an End).
A loop does not require a host.

Ashley has a chapter titled 'Loop Knots' in his book.
An example of a 'loop knot' as understood by Ashley in 1944 is #1010 Simple Bowline.
And so you might find cultural difficulty in using the term 'eye knot' in lieu of Ashley's
'loop knot'. Again, this depends on your epistemology.
And again, if Ashley is your primary source of truth and meaning, this would explain
your confusion with the word 'loop' (and nipping loop).

What is a nipping loop?
The term 'nipping loop' includes the word loop.
Its a loop that 'nips' (clamps).
In order for this to be true, both ends of the loop must be loaded.
A nipping loop is 'TWATE' - and therefore any structure that isn't 'TWATE'
is automatically disqualified.
A nipping loop has chirality (either 'S' or 'Z' chirality).
A nipping loop must be functional - its clamping force increase in
direct proportion to load.
The nipping loop is a key component of all 'Bowlines'.
The absence of a nipping loop automatically disqualifies an 'eye knot'
from being a 'Bowline'.
The nipping loop encircles and clamps both legs of the collar.
NOTE:
A nipping loops encircles and clamps material (eg the legs of a collar).
In this sense, the material being clamped acts as a host for the nipping loop.
Obviously, if there was nothing to encircle and clamp, the nipping loop would not exist.

What is a turn?
A turn forms around a host.
A turn is a line that curves around the shape of its host, in
most cases this is a cylinder/post. However, a turn can also
form around a host with edges (eg a square section).
A turn benefits from the capstan effect.
A turn has no overlap and does not cross-over itself.
A turn does have chirality.
NOTE:
If turns formed around a host overlap each other,
they are 'riding turns'. Riding turns can induce a binding
effect eg a Clove hitch.

What is a half hitch?
A half-hitch is a termination mechanism.
Half-hitches form around an S.Part and terminate a
loose tail end.
They are not loaded at both ends.
A half-hitch always exists within these parameters.
The term 'half-hitch' is actually a colloquialism for a method
of terminating (finishing) a loose tail end.

Summary:
I experience no confusion with the use of the word 'loop'.
Ashley is not the source of my truth and meaning.
Across all historical knot books, it is difficult to find
clear and unambiguous definitions of knots and knot
components. For example, the provision of a clear and succinct
definition of what a 'knot' is has been lacking with almost all authors.
Some people have difficulty evolving their own theoretical models,
particularly within a strong cultural influence of historical terminology.

For me - going right back to a basic definition of what a 'knot' is:
I dislike and disdain the use of 'tangle' in defining what a knot is.
A tangle strongly implies a confused mass of something twisted together.
There is implied randomness.

I prefer a definition that captures intent and repeatability.
Eg: The act of tying a knot with a defined geometry/shape is intentional.
It is a repeatable process (it is not random).

EDIT NOTE:
I found an 1884 knot book titled:
Knots Ties and Splices by Joseph Tom Burgess.
Link: https://ia601301.us.archive.org/12/items/cu31924014519940/cu31924014519940.pdf
At page 24, he identifies a loop.
Fig 17 is identified as an underhand loop (actually 'S' chirality).
Fig 18 is identified as an overhand loop (actually 'Z' chirality).
At Fig 153 he also identifies 2 loops.

I find this very interesting because he appears to have a concept
of what a loop is circa 1884.

Robert Birch has a useful glossary (updated to VER 1.4 2020):
Link: https://igkt.net/publications/32-recent-additions
Birch has defined what a loop is (at page 11).
He also defines turn (at page 16).
He includes in his definition of a turn; "around a solid".
He would have done better to use the term host (instead of solid).
A turn forms around a host - taking on the shape of the host.
A turn benefits from the capstan effect (my words).
He does not identify or define what a nipping loop is - instead
referring to a nipping turn.
I think he confuses concepts here...

At page 12, he attempts to define nipping turn as follows:
"A nipping turn is a turn that exerts pressure on a line (or lines) that it encloses, thus creating friction that is relevant to the security of the knot. Nipping turns are often half hitches. They may be uni-loaded (as typically experienced during use of a sheet bend ABOK #1431); or bi-loaded (as typically experienced during use of a bowline ABOK #1010..."
He would do better to use nipping loop in lieu of nipping turn.
Elsewhere in his narrative, he defines a turn as requiring a solid object (a host).
Obviously, in a #1010 simple Bowline, there is no 'solid' (no solid host).
Furthermore, and without exception, all nipping loops in 'Bowlines' are
loaded at both ends.
The nipping loop within a simple #1010 Bowline encircles and crushes rope material (not a solid).

He makes an attempt to distinguish between a loop and a turn based on
the presence of a "solid" (which really ought to be defined as a host):
Quote:
"Although the distinction between loop and a turn is clear-cut (based on the presence or absence
of a solid), there is a continuum of angles from a slight deviation over an anchor point to a
tensionless hitch with multiple turns around a solid."

He ought to include further illustrations that a loop is not a turn - and a turn is not a loop.
His reference illustration at page 1 is good - here he shows the presence of a host (his 'solid'), which
is a necessary element of a turn.

[Dan_Lehman]

My definition of a "bowline" is simpler.

It is an Eye Knot where the S.Part makes a circular path in
constricting/clamping of parts passing through it.
So, vs. that "It's Not A Loop" somewhat circular S.Part in
the hitching line of a Sheet Bend, I find some questionable
difference between same-side (not so round) & opposite-side
(more rounded) versions of the SB.  --where, to be sure,
here any "loading" is absent, but still the circular nipping
of a *loop* obtains.

Is the "Dbl.BWL" a BWL, with it's "round-turn" base?
Note that such a mulit-turn structure can be "cascaded"
into what Ashley's #488 shows --which is much a helix.
(And, as I've previously remarked, even with its lone
turn the #1010 BWL can also re-shape that to being
more (clearly) helical.)

So, I'm happy with those EK bases that give such a
"rounded"/surROUNDed gripping base,
but where the exit from that goes not out as the
Outgoing Eye Leg but perhaps into a collar structure
around the eye legs :: to which there might not be
so much *loading* but where that end of things
is held fast against pull S.Partwards, possibly with
a bit of tension opposite.
And in this sense, most certainly what we commonly
call "Half-Hitches" are loaded on both ends, except
for the last/end one.  (GRShaw noted for him HH
both in the fully looping & the like-a-TimberH. forms.)

Note: Ashley's illustrated #1012 Water Bowline has 2 nipping loops (they are separated).

And Mirror'd BWL? --which is like #1012 but with a Larkshead
(for more pure "mirror"ing :-) vice Clove structure --but also
with the Clove, a version.
Are these similarly BWLS with 2 nipping loops"?!

"Proper Collar" IMO has no great claim to determine
things; it serves to stabilize the loop, fighting to keep
it not-so-helical.  (BTW, with that loosely braided rope
one can insert the S.Part THROUGH its loop and have
a non-helix loop!)

But all this thinking is yet amenable to further consideration,
to seeing laid out the multiple forms & options.

BTW, re Ashley's asserted

Ashley has an anomaly at entries #1057, and #1058.
These structures are not 'Bowlines'.
It is difficulty to know why Ashley identified these entries as 'Bowlines'

is just a sounding on the then available naming
of such things.  I'll suggest that perhaps the BWL was so common
& de facto what was used for an EK that its name had some bit
of sense of "EK" to which then other candidate EKs the borrowed
"bowline" in this regard.  --these namers weren't rich with EKs
to give thought to.

In this, I've seen the #1017? Angler's Loop put forward as
a BWL on a bight (IIR).  IMO, it IS a BWL when Tail-Loaded
--the RELeg finish putting in a loop, so there you go : load it!
Now, yes, it's a bit dubious in stability (haul hard on the OH's
now-become-Tail to get the eye collar working in favor).
 

--dl*
====

[agent_smith]

Quoted from Dan Lehman:

It is an Eye Knot where the S.Part makes a constricting/clamping
of parts passing through it (key to the knot's staying tied).

Yes, we can at least agree that a 'Bowline' is a type of 'eye knot'.
The rest of your sentence is open to interpretation in terms of what
happens to the continuation of that S.Part.
It morphs into a nipping loop which is loaded at both ends.
A nipping loop is a loop that nips (ie clamps/bites).

So, I'm happy with those EK bases that give such a
"rounded"/surROUNDed gripping base
but where the exit from that goes not out as the
Outgoing Eye Leg but perhaps into a collar structure
around the eye legs :: to which there might not be
so much *loading* but where that end of things
is held fast against pull S.Partwards, possibly with
a bit of tension opposite.

Hard to visualise this without an accompanying photo.
I've bolded your words that are difficult to interpret with
100% certainty (per your actual intent).
It appears that your principal requirement for assigning
the name 'Bowline' to an 'eye knot' is the presence of a
functional nipping loop. Anything beyond that is not
essential to your requirements.
And I think this points to your reversed polarity (transposed)
'Anglers loop' - where there is no proper collar (per Xarax)
and instead, the 'collar' is now formed around both eye legs.
I - on the other hand - concur with Xarax that a 'proper'
collar is also a requirement.
In all of the 'Bowlines' illustrated by various historical
authors, we see both a functional nipping loop and
a 'proper' collar (per Xarax).
The collar performs a U turn around the S.Part, it
is braced upon the S.Part (the S.Part has a stabilising
effect on the collar).
And then both legs of the collar enter and pass through
the nipping loop.
In a #1010 simple Bowline, these elements are obvious
and self-evident.

Is the "Dbl.BWL" a BWL, with it's "roundturn" base?

Short answer: Yes, #1013 Double Bowline is a 'Bowline'.
The nipping loop is doubled - it traces out a 720 degree curved path.
Yes, the nipping loop is helical in shape.
I conceptualise a loop in a different way relative to a turn.
Ashley (circa 1944) is not my epistemological source of definitions.
A turn forms around a host and assumes the shape of its underlying host.
A turn benefits from the capstan effect.
Generally, the host is an external object (eg a post, a railing, etc).
For example; A round turn and 2 half-hitches tied around a post/tree.

And Mirror'd BWL? --which is like #1012 but with a Larkshead
(for more pure "mirror"ing :-) vice Clove structure --but also
with the Clove, a version.  Are these similarly BWLS with
2 nipping loops"?!

You appear to be asking for my epistemological evidence?
Ashley illustrates #1012 with separated nipping loops.
We can of course fuse the 2 nipping loops into a Clove hitch.
A Clove hitch is actually 2 superposed loops of the same chirality.
A Clove hitch is 'TWATE' (Tiable Without Access To an End).
Two (2) superposed loops of the same chirality is topologically identical
to a Clove hitch.
So whether the loops are separated or fused does not disturb the fact
of the matter... #1012 is still a 'Bowline'.

As for the 'Mirrored Bowline' - yes, its a "Bowline'.
The Girth hitch is 'TWATE'.
The Girth hitch is loaded at both ends.
A Girth hitch is actually 2 superposed loops of opposite chirality.
Again, we can fuse the loops, or separate them as per Ashley #1012.
Summary:
[ ] Clove hitch = 2 superposed loops of the same chirality.
[ ] Girth hitch = 2 superposed loops of opposite chirality.

"Proper Collar" IMO has no great claim to determine
things; it serves to stabilize the loop, fighting to keep
it not-so-helical.  (BTW, with that loosely braided rope
one can insert the S.Part THROUGH its loop and have
a non-helix loop!)

Xarax, if he were active in this forum, would disagree.
The collar and its 2 legs are a crucial component of a
'Bowline'.
Refer to the attached photo to see what happens when
the collar is absent.

In this, I've seen the #1017? Angler's Loop put forward as
a BWL on a bight (IIR).  IMO, it IS a BWL when Tail-Loaded
--the RELeg finish putting in a loop, so there you go : load it!
Now, yes, it's a bit dubious in stablity (haul hard on the OH's
now-become-Tail to get the eye collar working in favor).

What you are describing is a transposed 'Anglers loop'.
The tail and the S.Part have changed polarity/identity.
In this re-orientation, there is no collar (the 'collar' in fact forms
around both 'eye legs'.
I would go further and declare it to be a quasi anti-Bowline.
This is because the returning eye leg enters the nipping loop
from the same side.
(there is a nipping loop).
Again, we can see that your definition of a 'Bowline' only requires a
nipping loop. I think this reversed polarity 'Anglers loop' demonstrates
how the collar plays an important stabilising role - the absence of which
renders this quasi anti-Bowline unstable.
Because there is no 'proper' collar, under load, this 'eye knot'
is unstable.

...

The attached photo shows the role of the collar in acting as a
stabilising element within the 'Bowline'. When the collar is
deactivated/removed, it renders the structure unstable.

[Dennis Pence]

I will just repeat that I feel that the expression "nipping loop" implies a single loop.  I do not see how it allows a Clove Hitch, a Round Turn, or a Girth Hitch (none of which meets the definition you give for a "loop").  I want all of these to be included into the "family of bowlines" and so I am trying to argue for the definition to say "nipping part" or "nipping structure" and then the details to allow multiple loops follow and maybe even more detail about what "helix" or "circularized".  I don't think the Girth Hitch has the structure of a helix or that it is very circularized.  The Karash structure is just a half-twisted loop that seems almost closer to the original Bowline than a Girth Hitch Bowline.  I would like the definition to include all of these.

[agent_smith]

I will just repeat that I feel that the expression "nipping loop" implies a single loop.

Obviously I dont know you on a personal level and we have never met.
I am proceeding on the assumption that English is your first language (keep in mind that many people on this forum do not speak English as a first language).
You use the word "feel".
I have to state up front that facts don't care about feelings.
Your interpretation is false.
The definition is not restricted to the existence of only one (1) loop.
Logically, if there are two (2) loops, this implies there must be at least one (1) loop present.
So for example, Ashley #1013 is a Bowline with 2 loops.
It is still a 'Bowline' - and it has more than one loop (ie it has 2 loops).
Singular versus plural is irrelevant.

I do not see how it allows a Clove Hitch, a Round Turn, or a Girth Hitch (none of which meets the definition you give for a "loop").

False.
Refer to attached image below.
A Clove hitch actually consists of 2 superposed loops of the same chirality.
Do you acknowledge this as a fact? Yes / No ?

A Girth hitch actually consists of 2 superposed loops of opposite chirality.
Do you acknowledge this as a fact? Yes / No ?

I want all of these to be included into the "family of bowlines" and so I am trying to argue for the definition to say "nipping part" or "nipping structure"...

Your argument makes no sense, it is illogical.
All 'Bowlines' that have ever been published since the dawn of mankind have certain geometric characteristics.
You can objectively test this yourself. Take some time, and examine 'Bowlines' published by Ashley, CL Day, Budworth, et al.
You will notice some geometric elements that are common to all 'Bowlines'.
The only exception is the anomaly found in Ashley at illustrations #1057 and #1058.
I am of the view that this was a logic error (likely caused by following some previous publication or historical artefact - or an editing error).
I could also mention the so-called 'circus Bowline' (which isn't a Bowline - its actually the Farmers loop).

I don't think the Girth Hitch has the structure of a helix or that it is very circularized.

Why is the concept of a helix necessary?
Although I concede that a 'loop' is the beginning of a helical structure (and has the elementary shape of a helix).
And so it is a useful term to explain what a 'loop' is.
In Ashley #1013, there is a double loop.
I say "double loop" rather than 2 superposed loops.
We can say that the double loop in Ashley #1013 has the form of a helix.
But, this misses the key point:- it is the presence of a loop (or more than 1 loop) that matters.
It just happens to be that a double loop has the form of a helix.

The Karash structure is just a half-twisted loop that seems almost closer to the original Bowline than a Girth Hitch Bowline.  I would like the definition to include all of these

The so called 'Karash' eye knot is actually a quasi Bowline (refer to attached image below).
I use and interpret the term 'quasi' as per the standard English dictionary.
Definition: Used to show that something is almost, but not completely, the thing described.
This is an example of a nipping structure (rather than a nipping loop).
In this case, the nipping structure is a crossing hitch (same form as #206 Munter hitch).
And so here, the term 'nipping structure' is appropriate.

And again, your epistemological understanding of what a loop is requires investigation.
A 'Girth hitch' is topologically just 2 superposed loops of opposite chirality.
Do you not see this?
And a Clove hitch is topologically just 2 superposed loops of the same chirality.
Both consist of loops.
What differs is how they are geometrically aligned with respect to each other.