Evidently, stoppers are never tightened as hard as other types of knots ( loaded bends, for example ), so they do not not run the danger to jam to the same degree. So, the concern about a stopper being difficult to be untied is of secondary importance- in comparison to a bend, for example. The double and the triple overhand knot stoppers can, obviously, be tightened to the point they become a solid mass of rope, if one has enough rope length on both ends ( a rare situation in stoppers setting or use ), so he can anchor the two ends, and if he pulls them along opposite directions as hard as the ends of a bend are supposed to be pulled ( a non-existing situation in stoppers setting or use). I do not know any application where a stopper is supposed to be tightened, in settng or in use, to, say, 50 % of the rope strength, as a bend is, and if there is, it will be an extremely rare event indeed.
The way stopper knots are loaded is very different from the way bends and other types of knots are loaded. A symmetric bend derived from the half-retracement of a stopper knot (1) can be an easily jamming knot or not, irrespectably from the characteristics of the parent knot, and vice versa, because a bend knot is always loaded differently from a stopper knot.
Are you sure you’re not thinking of just one of the uses of stopper knots: their use to add security to other knots that bear most or all of the load?
In uses in which a line runs through an opening in a cleat support, or through a hole in a beam, bulkhead, or other rigid object, the stopper can be heavily loaded.
David
“Evidently” ?
At least, evidently stoppers do not appear in commonly presented
knot-strength charts (and if one saw e.g. “fig.8 (stopper) knot”
there’d be the question as to whether this was actually loaded qua
end stopper in resistance against some object, or merely as a
knob in the lint --what was given to me for the Dyneema 12-strand
line I used for eye-knots and which was said (overhand) to yield
about 31% strength).
So, I don’t know how one would employ a stopper knot in terms
of presumed strength, other than to use a “50%” rule of thumb
(obviously, not for HMPE or other hi-mod cordage!).
... so they do not not run the danger to jam to the same degree.
Fair enough. But one will read recommendations for the Fig.8 stopper
and vs. the overhand based on expected difficulty of untying.
The double and the triple overhand knot stoppers [i]can[/i], obviously, be tightened to the point they become a solid mass of rope, [b][u]if[/u][/b] one has enough rope length on both ends ( a rare situation in stoppers setting or use ), ...
Yes, and with mere one-side loading, things are not severe
(though just loading some aged arborist-like 5/8"? braid
and it got firm, but the stopper-face end could be easily
pried loose …) . But those float-bracing stoppers of the
commercial fisher need to be set tight --they’ll not get
much tensioning in use, but ageing.
I do not know any application where a stopper is supposed to be tightened,
in settng or in use, to, say, 50 % of the rope strength, as a bend is, …
“50%” ?? What rope use do you know of that expects this?
Usual safety factors, WLLs (working-load limit) are 10-20%,
possibly higher slightly(?) for hi-mod standing rigging.
The way stopper knots are loaded is very different from the way bends and other types of knots are loaded
By definition, perhaps. But then what does one call a knot loaded
on both ends --one use being in dock lines qua position marker,
another in gym/fitness climbing ropes (for purchase)? --a symmetric
Fig.9 (#521=> 525) is good here, in common materials.
–dl*
True, but not in the way a bend, a loop or a hitch is supposed to be loaded, that could easily lead to a jammed knot. I was only talking about the concern of tying a stopper knot ( as the double or triple overhand knots) that would be really difficult, or even impossible, to be untied, if tightened hard, in setting or in use. I believe that, first, seldom, if ever, stoppers would be as heavily loaded as the other types of knots ( the bends, for example), and, second, even when they will be as heavily loaded, they would not be loaded through pulling from both free ends, so they would not jam as easily. So, even if a stopper knot, ( or the symmetric bend that could possibly be derived from it through “half-retracing” ) is a relatively easily jamming knot through hard loading from both ends, this is not a danger that will ever be materialized in practice.
Oh, the word “evidently” was only used as a comment to the word “obviously”, and nothing else. 
The 50 % rule of thumb is a lower limit for every type of knot, I believe. Who would be satisfied with a knot that could not reach this number ? However, even in this “low” limit most known knots will be quite difficult to be untied, I think, ( the double and triple overhand knots will be difficult to be untied at much lower loadings… ), and stopper knots are not expected to be loaded as hard, and in the same way, as the other types of knots. So, I do not believe that those recommendations are of much practical value, in the case of stopper knots, and that is why I do not see any reason not to use the double or triple overhand knots as stopper knots ( provided their “width” - cross section area on a plane perpendicular to their axis - is wide enough for the specific application, of course). I do not think that the width of the new stopper knot discussed in this thread is such that is worth the additional trouble of the much lengthier tying and dressing procedure of this stopper knot, in comparison with the “similar” triple overhand stopper knot. The “X” crossing should be inside / enclosed in, the coils “tube”, and not on their outter shell, for the knot to have a really satisfactory width. Just my humble opinion, of course.
Just a figure of speech, I believe? What is “common” in those materials? Are the “contemporary” materials not common any more ?
I regard “common” to be those materials in broad usage,
in contrast to especially the “hi-mod” materials of HMPE, Kevlar,
Vectran, and so on, and we should include some forms of the
“common” nylon, polypropylene, … as well. (I’ve not yet focused
effort to try to fathom the variety of PP cordage I have found, but
it’s rather impressive --of stuff that grows brittle and with UV radiation
can splinter its color-faded bits, to some dog/horse lead that came
into my family circa 1968? (I think) --or at least 3 decades ago–,
was out on a mostly but not entirely shaded role as clothesline
support, and is smooth almost waxy w/o hint of degradation!?
–and of newer stuff that is hard like polished stone.)
BTW, I meant #525, and will edit above post to this correct
“symmetric Fig.9” reference.
–dl*
What is needed here is a classification of those materials according to their surface friction characteristics. With a slippery material, it is easier to set a quite convoluted stopper knot in a compact form, i.e. tighter, in the first place, and it would also be easier to untie this knot, if and when needed. So, I wonder if the comments made in ABoK #517 and #520 ( about multiple overhand knots being difficult to tie and easy to jam, in comparison to stopper knots using the figure eight knot as a base), have any relevance today, on those materials.
Therefore, I think that the double, or even triple overhand stopper knots are the most obvious and easy solutions for a stopper knot tied on contemporary slippery materials. And if I would like to add more width, I would not hesitate to start again from a base that uses multiple overhand knots, (instead of figure eight knots), in the manner of ABoK#578, for example ( a twice re-tucked overhand knot). On a slippery material, we can set such stopper knots in a compact form, yet we can untie them, if and when this will be needed, quite easily.
This is a non-sequitur : at least in some cases, the slickness
enables a tightening that renders what otherwise might’ve
been an untiable knot un-untiable (!) [This apparent double
negative doesn’t yield tiable ! ]
An eye knot based upon #525 (though I leave the tail not
fully tracing, only to an overhand form/extent) got
I think near impossibly hard to untie, at rupture (of its
at-other-end-of-specimen match); I think that (again)
“in common materials” this eyeknot remains able to be
loosened & untied --friction prevents the compaction seen
in HMPE. (In pulley loading, e.g., I have not seen it tighten.)
Similarly, knots like the Ossel hitch --ones that have parts
tensioned around an object to pull into each other (opposed
bights) and nipping every more tightly-- will work into good
tightness around a smooth metal pipe, but fail to get tight
around rope, e.g., because of the greater friction, and they
will be easier to untie.
Still, at times I think that there is something to the assertion
that easier-to-tighten carries a corresponding easier-to-loosen
balance.
–dl*
So, I see you were able to follow my non sequential reasoning…
The truth is that when I first wrote my reply, I had the sentence written as follows :
With a slippery material, although it is easier to set a quite convoluted stopper knot in a compact form, i.e. tighter, in the first place, it would also be easier to untie this knot, if and when needed.
Editing this to the one finally posted, was my way to make this “at times” more interesting to discuss.
So, is it true for the ABoK#517 and #528, or not ? My point was/is that, in “non-common”, slippery contemporary materials, those stoppers are easy to tie, and also relatively easy to un-tie, ( when loaded the way stoppers do ). For convoluted knots, the first part of the previous sentence is obviously/evidently true, but the second depends upon many things, so, yes, “at times”. Tie those stoppers with your, sun-burned or raw, material, and tell us your findings this time (at least… :)).
I have found the “Kolbe stopper” exactly what I have needed, plus being practical and easy to tie. In training retrievers, the trainer often uses a canvas boat bumper (dummy); about a 4-5 inch cylinder with a grommet at one end. A rope is tied to the grommet, allowing the trainer to toss the dummy in the field or water for the dog to retrieve. It should not be a loop since the dog may snag a paw in a loop. I have spent hours and hours trying to find (and tie) a knot which would be at the end of the tossing rope (10-12" long) allowing the trainer to hold onto the wet rope without slipping, permitting a longer toss. Using 1/4" woven polypropylene and polyester rope, I found a monkey’s fist impossible to tie (there is a klutz factor), and most other knots, including the Ashley, too small to give a good grasp. When I stumbled onto this website and chanced upon the Kolbe knot, I discovered that it was close but no cigar; the knot was still too small. However, by increasing the loops in Step 2 from 3 to 5, the knot size increased to about the size of a walnut, which is perfect for my purposes. I also found that by tightly pulling in the left loop in Step 4 and the right loop in Step 6, the added bulk of additional turns was tightly held and the “tossing knot” comfortable in the hand. (There is no intent to untie the knot, which may be the case with common stopper knots.) I have called my version the Kolbe 5 (5 turns). I think this technique (adding or subtracting turns) would be very useful in adapting different diameter ropes to this purpose.
Why wouldn’t you use either an eye knot with
a properly, tight-sized (unsnagging, i.e.) eye;
or simply a noose-hitch, which will cinch up snug
to the bumper’s grommet? (E.g., the poacher’s
noose (a strangle knot tied to the noose SPart)
I’d think would give you what was wanted.)
–dl*
I think C. Kirk is using the stopper knot at the other end of the rope, not the attachment to the grommet.