Oregon State University
Corvallis, OR 97331

Oregon Occupational Safety and Health Administration
Worksite Redesign Grant Final Report
July 2004
EXECUTIVE SUMMARY

Running Lines & End Connectors for Synthetic Rope to Reduce Workloads

In order to realize the ergonomic and efficiency benefits in logging and trucking
applications, suitable end connectors must be developed and tested for terminating
synthetic rope. At the start of this research and development effort, synthetic rope end
connectors were limited to specific splices, knots, and thimble/eye connectors. There is
a need to develop synthetic rope terminations to winches, steel wire rope connectors
(nubbins, fittings, etc.), and to synrope itself.

We reviewed potential end connectors used for wire rope and worked with the
manufacturer on ideas/concepts. We were not successful in working with
manufacturers of wire rope end connectors as they viewed synthetic rope as
competitive or had unsuccessful prior experiences. We consulted with experts in the
chemistry of the rope and epoxies to select potential systems of bonding rope to
connectors. Some of our early trials capitalized on the strength of the buried eye splice
used by the rope testing standards to establish the strength of the rope.

We have come to realize that the criteria for acceptable end connectors with synthetic
rope depend on how they are used. Some terminations need to develop high strength
because they are bearing loads while others may be terminations that either are
expected to break away or simply terminate the rope without having much of a load.
Another important criteria is the ease of production or manufacture in the field
conditions of a rigging shop or in the woods. Finally, end connectors should be
relatively consistent in their performance rather than variable in use. The table below
lists the end connectors evaluated.

End connector
Origin
Use
Average strength
& variability
Buried eye splice
Manufacturer
Eye to shackle
various connectors Standard 100%,
little variation
Long splice
Manufacturer
Connect two ropes
95% , little variation
Y splice
Manufacturer
Variable length, eye
for tensioning
50-90%, variable,
can slip out w/o
tension
Whoopie Sling
Manufacturer
Variable sling length 85-90%, little
variation
Knotsvarious
Marine industry
Terminations
8-58%, highly
variable
Cable clamps (clips) Wire rope industry
Connect rope to
itself
~60%, OK variability
tensioning difficult
Pinned nubbin
OSU-Hartter design Connect to nubbin
~95%, little variation
Knuckle link
Hartter design
Connect to steel
housing
~100% little
variation
Pressed nubbin
Wire rope industry
Connect to nubbin
~20-25%, little
variation
End connector
Origin
Use
Average strength
& variability
Butt splice packed
into nubbin
OSU Concept
Connect to nubbin
~10-15%, could be
variable
Chain link to buried
eye splice
Truck wrapper
design & others
Connect to chain, T
bar, etc.
Wrapper strength w/
reduced pin size
SEFAC Manufactured
end
connector
Connect to wire
rope or steel end
connectors
~40-65%, variable &
difficult to produce
Various tested
epoxies to steel
nubbins
Wire rope industry Connect synrope to
nubbins
~12-36% highly
variable & difficult
Twisters
Wire rope industry
Variable length &
tensioning device
~80% of double
rope strength


Most of the end connectors above were tested in a designed experiment documented in
the MS thesis of Joel Hartter (2004) under the grant sponsorship. Other tests were
conducted as well. We qualify our recommendations to the AmSteel�-Blue rope we
tested and urge caution for users until they have some experience with the connectors
themselves. Based on this initial work, we believe that the following list of end
connectors will be useful to industry adjusted as needed to meet the strength
requirements in use.
Buried eye splice Whoopie
Sling Long
splice Rope clamps in selected applications to low tension terminations Knuckle
link Pinned
nubbin Pressed nubbin, Butt Splice packed nubbin, drum connectors (various)For
breakaway or drum connections relying on sufficient wraps on drum Y-splice with careful construction and pre-tensioning with mostly rig up
conditions Twisterswith careful use not to over twist ropes Chain link to buried eye splice as in truck wrappers
We further do not recommend the following end connectors at this time:

Knots as they are variable and can have low strengths including knots as
recommended by rope manufacturers
Epoxy to nubbin connectors as they are extremely difficult to prepare and then
are variable in strength
SEFACan industry connector with difficult production requirements & variable
results

Our results to document the uses of synthetic rope for running line applications are
limited to winching applications in ground skidding, use of synrope on a carriage, and
using synthetic rope as mainline on a small yarder. All of the above running line
applications have been successful and show promise. We have learned important
lessons and identified problems and opportunities on drumline spooling and capacities.

We have documented the potential uses of synthetic rope as a skyline but have not as
yet done trials to verify the potentials. We could not incorporate synthetic rope in cable
planning analysis programs as yet but offer an approximation approach to see its
potentials. We are still working on using synthetic rope with various carriage designs.

We have produced two designs for end connectors that are in the public domain and
available to manufacturers or machine shop production: pinned nubbin and knuckle link.
We have studied damage and wear to synthetic rope in our project but still rely on the
manufacturers recommendations for replacement.









Acknowledgements

The entire synthetic rope research team would like to thank the Oregon Occupational
Safety and Health Administration Worksite Redesign Grant for the funding the project
and Mike Lulay of that agency for his assistance. We also thank Milo Clauson and the
Wood Science and Engineering Department for his leadership and their lab testing
facilities. Many cooperating rigging shops, suppliers, and logging firms helped with our
efforts. Samson Rope Technologies has provided assistance in many ways to the
project. It has been an interesting and challenging project whose results will continue
developing over the years ahead. TABLE OF CONTENTS


Introduction ............................................................................................................................. 1
Synthetic Rope End Connectors Evaluated and Designed..................................................... 2
Results of Laboratory Testing ............................................................................................... 19
Overall Results and Recommendations for End Connector Usage ...................................... 33
Running Line Applications, Drum Connections and Spooling, Carriage Uses...................... 37
Wear and Damage Evaluations ............................................................................................ 41
Planning Approach with Synthetic Rope............................................................................... 55
Future Research and Developments Needed....................................................................... 57
Conclusions .......................................................................................................................... 61
Sources................................................................................................................................. 63
Appendices ........................................................................................................................... 69
List of Tables and Figures:
Figure R1. Twister used with synthetic rope ........................................................................................15
Figure R2. Butt Splice packed into nubbin used as an end connector on a winch...............................18
Figure R3. Butt Splice packed into nubbin used as an end connector on a winch...............................18
Figure R4. Dimensions for drum/winch capacity equations..................................................................38
Figure R5. Gradation of color with normal use .....................................................................................42
Figure R6. Rope appearance fuzzed filaments and tufts...................................................................46
Figure R7. Section of skidder winch line located away from the working end......................................47
Figure R8. Section of a 3/8-inch ASB synthetic rope wrapper with accumulation of cut filaments ......48
Figure R9. Severe abrasion in a section of 7/8-inch ASB synthetic winch line ....................................50
Figure R10. Tail tree guyline with partial cuts in non-adjacent strands ................................................51
Figure R11. Pulled yarn single strand of a 12 strand ASB synthetic rope.........................................52
Figure R12. Fiber set due to compressive loading around the barrel of a drum winch ........................53
Figure R13. Grooves created by improper operation of fairlead arch ..................................................54
Figure R14. Rubbing on abrasive surfaces...........................................