By Julie Rahm
As you
know, a knot is a method of
fastening or securing linear material. Knots are usually tied with rope by
tying or interweaving. They may consist of a length of one or several segments
of rope, string, webbing, twine, strap, or even chain. A knot is interwoven
such that the line can bind to itself or to some other object. Knots have long
been the subject of interest for their ancient origins and their common uses.
Look
through any “Book of Knots” and find dozens of possibilities. Each knot has
properties that make it suitable for a range of tasks. Some knots are used to
attach the rope to other objects such as another rope, cleats, rings, or
stakes. Decorative knots usually bind to themselves to produce attractive
patterns.
Unknown to
some, knots weaken the rope in which they are tied. When knotted
rope is strained to its breaking point, it almost always fails at the knot. The
bending, crushing, and chafing forces that hold a knot in place also unevenly
stress rope fibers and ultimately lead to a reduction in strength. The exact
mechanisms that cause the weakening and failure are complex and are the subject
of continued study.
Relative
knot strength, called knot efficiency,
is the breaking strength of a knotted rope in proportion to the breaking
strength of the rope without the knot. Determining a precise value for a
particular knot is difficult because many factors can affect a knot efficiency
test: the type of fiber, the style of rope, the size of rope, whether it is wet
or dry, how the knot is dressed before loading, how rapidly it is loaded,
whether the knot is repeatedly loaded, and so on. The efficiency of common
knots ranges between 40 to 80-percent of the original rope strength.
In most
situations forming loops and bends with conventional knots is far more
practical than using rope splices, even though the latter can maintain nearly
the rope's full strength. Prudent users allow for a large safety margin in the
strength of rope chosen for a task due to the weakening effects of knots, aging,
damage, and shock loading. The working load limit of a rope is generally
specified with a significant safety factor, up to 15:1 for critical
applications. And, the Ashley Book of Knots, written by Clifford W. Ashley in
1944, is generally considered the definitive book on knots. You probably have a
copy on your bookshelf!
So, this
week, I tell you all about knots because most of my clients come to me with
knotted-up relationships. Their “relationship knot” is in the middle of their
relationship rope with each pulling hard on opposite ends. In order to remove
the knot, each must stop pulling. Once the tug-of-war stops and there is some
slack in the rope, the relationship knot can be removed. There is simply no way
to unknot a relationship without any slack! Learn more about unknotting relationships
by contacting me at my website, http://www.AmericasMindsetMechanic.com.
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