Sunday, March 3, 2013

Knot so Funny

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, 

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