Author Topic: Linemen Knots  (Read 103 times)

Dan_Lehman

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Linemen Knots
« on: January 29, 2019, 01:31:05 AM »
This began as a reply to another thread,
but I realized that I was digging into such
a separate topic that that should have its
own --and better placed, forum-wise-- thread.

I had a chat about this with a lineman recently. The cable they use for guys is called "guy strand", and it is of 1x7 construction. The short bits used for making terminations are called "dead-ends" (in local parlance, at least), and as you said they are sized to fit just so and are preformed into a helix. The dead-ends have dabs of paint to indicated where the wrap needs to start in order to obtain the requisite length.
Ah, we're getting close to Knots in the Wild --real stuff,
and not in-the-books-copied_&_parroted-forever!

I watched one pair of guys installing such a guy line and
dead-end (I'd think "eye" still a better name); it seemed
to me that at about the mid-wrap point the experienced
guy of the two --doing the wrapping-- had the other guy
allow a bit of tension into the line prior to making the
finishing (away from eye tip) wraps?!  --my surmise (and
my recall).
(This sort of matches what I'd think would be the best
way to seize and eye --to have the away-most
seizing be on slightly slackened tail so that it (which
will be the *point of entry* for the SPart; the initial
contact point of other strands and offloading...)
will take up force only at higher loads, coming to the
assistanced of the nearer-to-eye seizing which will be
getting more load at first.)


With "linemen", I hope to somewhere, somehow, get
insight & literature circa 1915 of the use of "linemen's
loop",
aka "butterfly knot".  I'd think that there
should've been some documentation of this knot which
reportedly (Burger, cited by CLDay's Art of K&S)
was in their repertoire.  (And, today ... ?)

Well, here's something coming up from Googling "linemen..."
www.linemanchannel.com/media/efficiency-of-knots-/7603
Points of things standing out to me:

0) no remarks about knots and HMPE lines,
but in the video of types & care of rope, they clearly show
Samson blue 12-strand Dyneema (HMPE) rope.
1) "Alpine knot" vice "butterfly" or "linemen's" ! (no strength rating)
2) square knot : efficiency 60%
3) running bowline & likewise "snubbing knot" (=backhanded/crossing knot + 2hhitches) 50%
4) "sheet bend knot" : not rated !? (poorly tied in "no hands" video)
5) clove hitch : 60% (no note re relative size of hitched object
6) bowline on a bight = bwl = 65%

I wrote in # 3 "likewise" because I thought that the likeness
(which was pertinent for strength) came in both of these
structures having the SPart drawn through a bight/eye
of rope, and . . .
... then I recalled that so far as I can discern, the break
in the running bwl came in the *knot* and not at
the eye --look for the broken strand! (in which case one
must really ask how the knot when coming AFTER such
an off-loading-of-force point as the passage of noose
SPart through eye point can be weaker than the
knot alone ? !!!  Well, their test of it was around a rather
small ring, and the knot bore against the eye (but, still,
THAT doesn't strike me as an extra weakening!?).

I'm really impressed that they got "60%" for the
squaREef knot --one might wonder if someone
was reporting, as occasionally is done, "strength LOST"?!

Another linemen's site
www.linemantrainer.com/apps.html
gives these knots as to-know from their apps:
KNOTS
Blood knot,
bowline on a bight,
bowline,
clove,
double sheet bend,
Farrimond friction hitch,
figure 8,
grapevine,
lanyard,
Lineman?s loop,
monkey fist,
Prusik,
running bowline,
sheet bend,
snubbing knot,
square knot,
taut-line hitch.

At least they know that they're "linemen" and not "alpine"!


Thanks,
--dl*
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