This Rigger's Handbook is dedicated to Theodore C - Igor Chudov

Winch Lines
CLEANING
Sometimes utilities have adopted the very good practice of
carrying at all times, a spare (clean and dry) winch line enclosed
in a plastic bag, enabling crews in the field to quickly replace a
damaged, soiled or wet winch line. Samson winch lines can be
washed in a mild detergent and warm water, rinsed and air-dried.
The polyester fibers themselves actually absorb only a negligible
amount of water, but water trapped between the fibers should be
squeezed out (by placing the line under tension) and air-dried.
SHOCK LOADING
Shock loading of any line – synthetic, manila, or wire – produces
a drastically different set of physical properties and results as
compared with normal loading. Shock loading, most simply
described, is a "jerking" or "snatching" or a line. Or, a very
sudden change in tension – from a state of relaxation or low load
to one of high load. This results in accelerated wearing.
A typical shock load on a winch line occurs when an object is
lifted vertically with a sudden jerk, or when this load is suddenly
dropped. A 5,000 pound load, under these conditions, may then
"weigh" 30,000 pounds – and break a winch line rated in this
strength range.
A 4" sudden drop – as off a platform – can actually double the
load. Similarly, an over-wrap "falling off" the winch drum can
result in a 50% shock load.
Assume that you have seven identical ropes – each with a
30,000 lb. breaking strength – and you work these ropes daily –
each rope lifting a different load, as below – for example, in a
winch line application:
WORKING NO. OF LIFTS
BREAKING WORKING LOAD BEFORE
STRENGTH LOAD FACTOR FAILURE*
1. 30,000 lbs. 5,000 lbs. 6/1 1,000
2. 30,000 lbs. 6,000 lbs. 5/1 750
3. 30,000 lbs. 7,500 lbs. 4/1 500
4. 30,000 lbs. 10,000 lbs. 3/1 300
5. 30,000 lbs. 15,000 lbs. 2/1 100
6. 30,000 lbs. 20,000 lbs. 1.5/1 25
7. 30,000 lbs. 28,000 lbs. 1.1/1 5
*Relative values only
This illustration clearly shows the higher the Working Load
Factor the greater the Service Life, and the lower the
replacement factor. Thus, a Working Load Factor also related
directly as an "Economy Factor."
Your may turn this around and look at it another way: If you're
always lifting the same weight; then, the stronger the rope (and
higher the Working Load Factor) – the longer the rope will last.
FATIGUE
Synthetic fibers have a "memory." They function similar to metal
(wire) in that they remember and retain the effects of being
overloaded and shock loaded. This is an important reason to
stress winch line procedures which reduce danger of shock
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72
YOUR SLING AND RIGGING SPECIALIST
loading... in order to prolong the life of the line and reduce
premature down grading. If there is reason to believe that a line
has been shock loaded above its recommended working load, it
should be logged; and if a number of these occur, the line should
be rotated and inspected.
VISUAL INSPECTION
The load-bearing capacity of Samson Stable Braid and Nystron
Ropes are divided equally between the inner core and the outer
cover – thus, despite damage to the outer cover strands, you
have an intact inner core capable of supporting approximately
50% of the applied load... an important reserve safety factor.
Spectron II has 100% of its load bearing capacity accomplished
by the core.
DISCARD POINT
Continued use and normal wear in the line gradually diminishes
the ultimate bearing strength and lowers the factor of safety. In
determining the proper discard time of Samson winch lines, the
following guides are suggested:
a. If as many as 1/2 of the cover strands are cut at a given
point, this damaged section should be cut out. If within 10 feet
of the eye, put in a new eye splice. If over 10 feet, rejoin the
rope with a Standard End-for-End Splice per the Splice
Manual. The rope can then be put back into normal operation.
A few damaged strands spaced out along the rope at intervals
is no real cause for immediate concern, but should be watched
and periodically examined.
b. If the individual cover strands have been worn down after
extended use to within 50% of their original bulk over an
extended area of the line, then the line should be discarded (or
assigned to a less critical task). This can best be determined
by an examination and comparison of the bulk of an individual
strand which is exposed and subject to wear with the same
strand where it crosses under other strands and is protected
(and therefore is full size).
c. Another guide for determining discard time is when the rope
has a residual strength of 50% of its original new rope
strength. This can be determined through laboratory tensile
strength break tests. This can be done by Hanes Supply. If
utilities wish to perform their own tests, they should contact
Hanes Supply to coordinate testing procedure, methods and
apparatus. Hanes Supply has instructions on technical
procedures for testing braided synthetic ropes.
TRAINING
A Preventative Maintenance and Safety Program in the use of
winch lines is strongly recommended. Hanes Supply will assist
in this.
Samson winch lines, used and cared for properly, will render
years of efficient, economical, and trouble-free service.
Winch line replacements, either in cut lengths or 600 ft. spools
are available through Hanes Supply.
Samson Ocean Systems guarantees its products against
manufacturing defects, but can't be held responsible for failure
or accident due to improper use or failure to observe prescribed
procedures for usage, as set forth above. Write to Samson for
Guidelines on Care, Usage & Inspection of Rope.