A method I've used is to carefully cut the rope with scissors and heat seal the
end with a blow torch. Then the rope is fitted around a thimble (is this what
you mean by a D ring?) and 'whipped' into place. ( I need to be careful here,
because some of the subtle differences between English English and American
English can cause confusion) Whipping consists of wrapping the rope aound the
thimble and laying the open end against the fixed end. Then a smaller cord is
used to wrap tightly around both. Done properly, this is very strong.
A rule of thumb is that a knot has 50% of the strength of the rope, while a
well done splice has about 75 to 80% of the strength of the rope. My experience
is that the most strain appears on the rope during erection: obviously, the
greater the guy tension for any reason, the greater the compressive force on
the mast. So you can get the situation where the mast buckles before the guys
break.
73
Peter G3RZP
========================================
Message Received: Feb 04 2006, 01:46 PM
From: "Rich Osman N1OZ"
To: "TowerTalk"
Cc:
Subject: [TowerTalk] Guy Rope Termination
I'm putting together a 45 ' temporary mast package. I'm using the 4'
military surplus sections that it seems you see at every hamfest.
I've got 3/16" double braid Dacron rope for low stretch guys. Most of
the double layer rope I've used in the past was pretty finicky about
treating the cut end, both in terms of how the cut is made and
processed, and also the way it is looped and knotted on the D ring. The
big problem I've seen is unequal tension on the inner and outer weaves
leading to failure of one and the the other.
I emailed the manufacturer and they were surprisingly unhelpful, saying
in essence "use a hot knife, we only make it, we know nothing about
application."
I'd like to engineer a solution rather than hack one. Starting with the
guys I want to be able to calculate the real guys strength. I'm
concerned that the terminations will end up being the weak points.
Can anybody out there point me in the right direction? I've googled
every way I can think of and don't seem to know the right terms.
--
Rich Osman, N1OZ mailto:n1oz@arrl.net
Rich Osman; POB 93167; Southlake, TX 76092 (Near DFW Airport)
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