Starting with this chapter, we explore another
major area of steelworking skills-the erection and
assembly of steel structure. Steelworkers require
tools to hoist and maneuver the steel members into
place to erect a structure of any magnitude. These
hoisting tools range from uncomplicated devices,
such as tripods and gin poles, to more complex
mechanisms, such as cranes and motor-powered
derricks. Whatever the case, one of the most
important components of these hoisting mechanisms
is the fiber line or wire rope that must be attached to
and hold the load to be hoisted and maneuvered.
Before you, as a Steelworker, can become skilled in
the supervision of hoisting devices, you must first
understand the use and maintenance of fiber line and
This chapter and the next are designed to
familiarize you with the different types of fiber line
and wire rope commonly used by Steelworkers. We
also discuss knots, bends, hitches, clips, and fittings
and describe how they are used. Other topics
discussed include the handling and care of fiber line
and wire rope, making splices in fiber line, and
methods of determining safe working loads.
TYPES OF NATURAL FIBER LINES
Vegetable fibers commonly used in the
manufacture of line include manila, sisal, hemp, coir,
the line. Manila line is generally the standard item of
issue because of its quality and relative strength.
The next best line-making fiber is sisal. It is made
from two tropical plantssisalana and henequen.
The fiber is similar to manila, but lighter in color. It
is grown in the East Indies, Africa, and Central
America. Sisal fibers are usually 26 to 40 inches (65
cm to 1 m) long but are only about 80 percent as strong
as manila fibers. Sisal line withstands exposure to
seawater exceptionally well. It is frequently used in
towing, mooring, and similar purposes.
Hemp is a tall plant that provides useful fibers for
making line and cloth. It is cultivated in the United
States, Russia, Italy, and South America. Hemp was
used extensively before the introduction of manila.
Throughout the Navy the principal use is for small
stuff, ratline, marline, and spun yarn. Since hemp
absorbs tar much better than the hard fibers, these
fittings are invariably tarred to male them water
resistant. The term small stuff is used to describe
small cordage that a layman may call string, yarn, or
Tarred hemp has about 80 percent of the
strength of untarred hemp. Of these tarred fittings,
marline is the standard item of issue.
Manila is a strong fiber that comes from the leaf
stems of the stalk of the abaca plant, which belongs to
the banana family. The fibers vary in length from 4 to
12 feet in the natural state. The quality of the fiber and
its length give manila line relatively high elasticity,
strength, and resistance to wear and deterioration. A
good grade of manila is cream in color, smooth, clean,
and pliable. Poorer grades of manila are characterized
by varying shades of brown. In many instances, the
manufacturer treats the line with chemicals to make it
more mildew resistant, which increases the quality of
Coir line is a light line made from the fiber of
coconut husks and is light enough to float on water. A
resilient rough line, it has about one fourth of the
strength of hemp; therefore, the use of coir is restricted
to small lines.
Cotton line is a smooth white line that stands much
bending and running. Cotton is not widely used in the
Navy except, in some cases, for small lines.