Cordage, Rope and Twine . . .
The Machines for All Ages
The need to pull, haul, lift, hoist, hold, or otherwise control objects
has been around since the beginning of civilization. This required what
today is generally called a "strength member" and has used over
time what is essentially an "assemblage" of fibers. In the earliest
days it was simply an assemblage of vines or natural fibers, usually indigenous
to a particular area of civilization. The pyramids of Egypt and the Aztec
dwellings of Mexico, among others, could never have been built without the
use of natural fiber strength members, very probably aided by mechanical
schemes which today would be identified as block and tackle.
Quantum Leaps
With the advent of man-made fibers, rope and cordage took quantum leaps
in capability, and today represents one of the most versatile and effective
"tools" available in the world! In fact, rope and cordage strength
members are essentially a "machine" ...
Machine: an assemblage of parts that transmit forces, motion, and energy
one to another in some predetermined manner and to some desired end.
(Webster, Third International Dictionary)
Combinations of fibers and constructions are designed to perform in some
predetermined manner and to some desired end--be it size, strength, weight,
elongation, abrasion resistance, torque, or some other criterion.
Technical Information
As with any machine it is important that its capabilities
and limitations be understood, and that its potentials be fully utilized.
This is one reason why The Cordage Institute includes technical information
in its mission. The goal is to provide generally accepted data, guidelines,
and specifications that can assist the engineer and the user in the most
effective evaluation, selection, safe operation and inspection of fiber
rope and cordage strength members.
With the development of today's industrial-grade, high tenacity, man-made
fibers, it has become possible to produce strength member "machines"
of great strength and durability, ranging in size from archery bow strings
to the mooring of giant supertankers !
High-Performance Cordage
The introduction of very-high-strength (high-modulus) fibers has even further
expanded the potential for fiber strength member "machines". It
is now possible to have cordage and ropes with strengths up to 10 times
the strength of steel for their weight, with comparable near-zero stretch,
as well as being noncorrosive and very flexible. This has the potential
for revolutionizing the capabilities of fiber rope "machines,"
especially for the replacement of wire rope in many applications. Already,
their applications have ranged from the use of pencil-thin cord as an artificial
ligament to tethers for high-altitude balloons and outer space vehicles,
to deep sea umbilicals, to antenna guys, to lifelines on navy vessels, for
high-capacity lift lines, and for the mooring and towing of large vessels.
Technical recommendations and guidelines are provided only as a reference
for making an ultimate determination as to the suitability of a particular
cordage or rope for a specific application or use. Designers and users are
urged to consult with qualified manufacturers and/or engineering consultants
to make the most efficient and cost-effective choice. In the final analysis,
responsibility for design and use decisions rests with the user.
Note: Refer to the Publication Catalog for information on subjects covered
by the Technical Information Manual and for specific documents to assist
in design and use.
