My angle has - and probably always will be - knots used in human life support (ie mission critical applications).
I respect those who use knots for decorative purposes, but that is not my personal area of interest.
If you tie a decorative knot incorrectly, there wouldn't be catastrophic failure with attendant death or disablement.
Don't forget other practical uses of knots, such as commercial fishing--which unlike angling uses ropes of equal
and greater size than life-support applications; although in most cases knot failures in ComFish shouldn't result
in personal injury, you can imagine that those whose very engagement in the whole activity DOES have some
considerable (asserted to be highest ...) risk, and whose livelihoods depend on results, do not have great
tolerance for cordage failure, BUT, OTOH, have some experience and that also can be edifying. (I think that
were some new rigger to make a trawl of lobster pots and then those trawls be pulled up losing all the pots
that it
might become a personal-injury matter!)
Here are the knots that I would like to put to the guild as a starting point for analysis:
KNOT ABoK No. CATEGORY ALTERNATIVE NAMES
1. Figure 8 loop # 1047 End line knot Figure 8 on the bight, Figure 8 follow-through
2. Re-threaded figure 8 #1047 End line knot Rewoven figure 8
3. Double figure 8 loop #1085 End line knot ?Bunny ears? (a truly ridiculous name)
4. Clove hitch #1178 Mid line knot
5. Double fishermans knot #498 & #1415 Joining knot (bend) 'Double English knot' & a 'Grapevine knot'
6. Prusik Hitch #1763 Sliding friction knot
7. French prusik #1758, #1764 Sliding friction knot 'Machard Tresse'
8. Tape knot #1412 Joining knot (bend) Ring bend, Water knot
9. Alpine butterfly knot #331 & #1053 Mid line knot Linemans loop, Butterfly
10. Munter hitch #1195 & #1818 Load control hitch ?Italian hitch? or ?HMS? or ?Mezzo Barcaiolo?
11. Rosendahl bend N/A Joining knot (bend) Zeppelin bend
I regard #1 & 2 as identical knots, different tying methods. (An interesting field study would be
to see if in fact the so-tied knots actually do generally result in identical knots, or, rather, if each
method has a bias toward one vs. another version of the Fig.8. E.g., the most natural/easy way
to begin "re-threading" is a way that could lead to the Weak Perfect form; and sometimes it
seems that torsion build-up in tying in the bight leads to an imperfect completion.) Interesting
that the Fig.9 is missing, though
LoaL asserts that it's regarded as dominant in the UK.
Hmmm, I wonder at not having some variation of Two Half-hitches in the set: what if one needs
to tie off w/o access to the rope end? 2HH w/stopper finish (Slip-knot, for bight tying), or the
Anchor hitch w/similar stopping, makes a handy way to effect this. One can also tie a variation
of Bowline. --or mere Hhitch w/bight through bight ... & Slip-knot finish.
Note: Knot number #11 is controversial. There are conflicting ideas about which 'bend' is optimal
One can re-tuck ends, which might both bump strength and further remove loosening => untying risk.
(the tape knot is not used by many Australian rescue teams on account of the wide availability of heavy duty sewn web round slings).
And they join any such slings by metal? I'm still waiting for someone to figure out that a multiple "girth hitching"
(a name I do NOT like for this, but it's in the parlance currently) of slings makes seeming sense, at least until/if
testing shows some reason to avoid it.
I'm going to re-assert the 4 S's which are:
1. Suitability to task
2. Stability (very important)
3. Security (very important)
4. Strength (not as important serials #2 and #3)
I guess #1 is pretty much the obvious: if one is going to tie two rope ends together (say,
to make an endless loop/sling), a stopper knot or hitch is not going to be used. It otherwise
is the entire consideration! As to the importance of the others, one might challenge the
idea that a knot for tying in needs to be
stable, if one keeps the eye small--i.e., that
the chance of any "abnormal" loading is effectively removed. In the same way, I could
see that
security in the sense of
untensioned security might be deemed irrelevant
where the task at hand didn't have any untensioned period--and were it some heavy
loading, untiability might be a key characteristic (slack-security, stability, material efficiency
all being put aside).
But this direction entails knowing
knotting more than merely being able to index from
a list of predetermined tasks into a set of knots, really.
For example, there are instances where a clove hitch or a butterfly knot might work,
but one might give optimum performance.
... or not; or the trade-offs might be too hard to evaluate to any reasonable degree of clarity.
(or even depend upon material!)
Here is another link for you Dan: http://www.forestry.gov.uk/forestry/kirn-5lebje
Report date: 2002
Title: Ropes and Friction Hitches used in Tree Climbing operations
Author: Paolo Bavaresco, Treevolution
Yes, I need to submit some analysis & questions re this to Paolo. I find some of the results
confusing/inconsistent (but might be misunderstanding the test configuration).
Now, about critiquing these various test reports, that remains on the to-do list.
A general critique is that they don't show exact knots/knot-geometry at play; this means
that one can only guess at the significance of the test results. On break tests, a general
criticism (or wish item) is that they don't say where the break occurs. E.g., for a Sheet Bend,
is it usually the bight or the loop part that breaks? --
that much would be easily told
(which rope ...), as opposed to exactly where in the bight/loop it broke.
--dl*
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