Strait Bend Testing?

[Dan Lehman]

Originally Posted by allene

According to this report LINK, the EDK is just plain dangerous and shows up 3:1 in accident reports even though it is not used by most climbers.

??? ! This is a gross misreading on both accounts : (1) the "EDK" is by consensus
--and w/o further qualification-- the denotation of the offset water knot (overhand)
and of the 4 listed possible knot failures in this article only *1* of them pertains to that
(the others are for the similar, offset fig.8 bend );
(2) I see nowhere a basis for your assertion about knot-use frequency?!
Indeed, one might find an opposite implication in Tom's
> ... is widely used for joining two rappel ropes together.
> Most of the people I know use the [offset]-overhand,
> ...
> I also know that millions of rappels have taken place on these knots without failures.

I forget what some occasional on-line/per-forum polls have shown re usage, but let's
just agree that the OWK (aka "EDK") is used a lot --in pure count of instances--,
regardless of overall proportion, be that a half, a third, a fifth, or whatever.
.:. It has been put to a practical test of usage, by any measure. And there are NOT
(m)any reports of it failing --you can read the one cited by Tom and regard it, as does
the reporter, as dubious in significance (too little is know for sure).

It also talks about the desire to have an asymmetric knot
so that the knot can be flat on one side and therefore not get stuck on a ledge.
The EDK excels in that regard but the Strait Bend doesn't seem that bad.

Better terminology: "offset knot", "knot is offset from the axis of tension", "butterfly
bend". Indeed the butterfly (knots) are asymmetric, but not in the way (mis)used
here, but in pure terms. They are not offset knots and so do not present the pure
ropes strands aligned with the axis of tension that is regarded as beneficial in some
applications; i.p., the collars of the knots encircle the knot. --just having tails exiting
together and perpendicular to the axis of tension isn't a sufficient condition for "offset".

But the bottom line is safety and more people are injured from the EDK rolling than from having to go back to free a knot stuck on a ledge.

Here, again, I see no basis for this assertion from the article. Tom does say that he
has not, as a member of an SAR team, witnessed problems from stuck ropes. (This
is a bit shy of saying that such problems didn't occur; they might have, but simply not
have resulted in a call for SAR --a matter of inconvenience/annoyance w/o rescue need.)
Some of the on-line surveys I've read have had similar personal testimony ("I've used
a grapevine bend for decades w/o ever a stuck rope.", e.g..)

> The article I linked has a pretty good discussion in the EDK.

But a not-so-good illustration of it (as Tom has been advised) : the lighter-grey
tail should be shown exiting on the right/below the darker one (for symmetry and
for security, resistance to flyping). As it is, it has come to a position that loading will
want to draw it to, and which drawing can be resisted by tying off this lighter tail around
the darker one with an overhand or in making a full encircling of the joined lines at
the *throat* of the knot (which greatly inhibits flyping) and thus forming a figure nine
(sort of 1-turn-shy-of stevedore knot ) in that lighter-grey line.

The EDK will be a hard sell on this forum among us cordage geeks who love a fair entry and symmetry in a bend

Which love should make you discard the butterfly bend in favor, perhaps,
of the truly symmetric Ashley's bends #1452 or 1408 ! The asymmetry of the former
was a consequence got from circumstance --tying mid-line, w/o tails--; presented with the
happier condition of using tails, why stay asymmetric?! (But do note my recommended
precise butterfly form described in a separate post above --that does look good!)

you are feeding the 'pull' rope through the rap rings you are at while pulling it
... when the other rope falls free

I thought that this might be what you had in mind. I can see this as okay in instances
of pretty sheer wall & need for such haste, but in some cases I should think that one
would prefer to coil and re-toss the lines out away from the wall in order to ensure a
free fall back into it, vs. risking a dropping of the line straight down into who-knows!
Thanks.


The thrust of my comments here should be understood as this:
knots are too frequently given cursory and inaccurate consideration,
with all sorts of myths echoed. I hope that one can achieve a better
understanding of the knots, here; and that one can see how much has been mis-stated
and misunderstood but yet advanced as popular wisdom.
(Frankly, were it to come to relying on some hastily tied end-2-end joint by someone
with limited appreciation of knotting, I'd feel more assured of an offset water knot
backed by the same, then of the somewhat complex butterfly
(which has one known mis-formation that has led some to seek nominal distinction
between "butterfly" & "Alpine butterfly" !). If ya can't tie knots, tie lots!?
But should an activity countenance such limited knotting knowledge?
--as we might soon see with driving, and vehicles equipped with new-fangled
collision-detection/-warning systems that some might cite in defence of using
cell phones while driving?!)


--dl*
====