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Prospects for Using Synthetic Rope in Logging:  First Look and Future Research Steve Pilkerton,  John Garland, John Sessions, Ben Stringham Department of Forest Engineering Oregon State University

Research Cooperators OR-OSHA Worksite Redesign Grant Sampson Rope Technologies, Ferndale WA Beth Dodson Coulter - OSU FE Milo Clauson - OSU Forest Products OSU Student Logging Crews; 1999, 2000

OBJECTIVES Evaluate potential to replace steel wire rope for improved worker ergonomics and logging efficiency Quantify heart rate exertion and recovery Laboratory strength tests of ropes, knots, and end connectors

Potential For Logging Safety Improvement Disability Claims: 27 percent are chokersetters, rigging slingers, and hooktenders 37-50 percent of claims related to overexertion and falls within this group 45 claims, $13,000 avg., $580,000 50 claims, $ 20,000 avg, $1,000,000 Jaggers! Sustained exertion / musculoskeletal stress

Rope Description AmSteel-Blue (Sampson Rope Tech.) 12-strand braided rope UHMWPE (ultra high molecular weight polyethylene) Urethane coating (slippery) Floats, non-absorptive material Low stretch, 0.8 ft. in 100 ft. @ 30% BS High wear & flex-fatigue life Easy splicing

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Ergonomic Field Trials Dragging 150-ft. length, carrying as a coil (steel = 111 lbs., synth. = 18 lbs.) 4 % road grade, 25 % ridge slope, 45 % side slope Climb & rig intermediate support tree Skidder bull line (winch line) Heart rate every 5 sec., task / recovery Task time

Heart Rate and Task Duration for 25-year old male to carry a 150-foot coil, 150-feet on 25 percent slope

Ergonomic Results Carrying coil better than dragging rope With synthetic rope: heart rate decreased faster heart rate recovery task time decreased Climbing and rigging, minimal improvement Skidder bull line: stat. signif. difference by rope type, slope, and gender

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Laboratory Testing of Ropes American Cordage Institute Standards 10 load cycles to 50 % of ultimate,11th cycle to failure Ropes:  Approach manufacturer’s specs Knots: 30 to 50 percent of ultimate Epoxy nubbins:  40 percent of ultimate

Rope Failure Results Less lateral movement on failure, occasionally 1 strand intact Failure generally in rope, not in splice Twisters:  up to 8000 pound tension, achieved 75 percent of ultimate Used ropes: 65 percent of original strength Diameter of rope increased (fuzzy) Dirt / debris in fibers (weight increase)

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Economic Potential Costs 4 to 6 times more Skidder Bull line scenario: 10 percent productivity increase 4 to 5 more turns a day $ 50 - 100 more per day to contractor Capital investment for lower unit costs Newer product, limited production quantities:  Price decreases possible

Potential Economic and Environmental Efficiencies Reduced need for more expensive system Increase lateral distance, decrease area in skidtrails Decreased roading requirements Cable equipment set-up improvements Faster manual work Additional applications to be discovered

Skyline Logging Simulated payloads with synthetic skyline Increased payloads leads to increased productivity and lower costs Example:  1500 foot span, zero chord slope, full suspension at midspan Greatest increase at low deflections, payloads decrease with increased deflection

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Future Research: Project 1 INDUSTRIAL FIELD TRIALS Static Lines:  Guylines, lift tree rigging lines Skidder Winch lines Log Truck wrappers Establish wear and damage criteria

Future Research: Project 2 EVALUATE FURTHER POTENTIALS: Additional end connector testing Drum spooling and mechanics Running line applications Cable harvesting analysis software (LOGGERPC) modifications Carriage slackpulling and tensioning Economic benefits as running lines

SUMMARY Material strength suitable for logging applications Improved safety, ergonomics, economics Upcoming research to describe and quantify applications, limitations, useful life, and replacement criteria

SUMMARY Expand on the foundations of wire rope and cable harvesting research of the 1960’s and 1970’s Pick up the potential of synthetic sheaves / blocks  research of the 1980’s Advance the field with 21st Century materials and applications Innovation in the hands of the practitioners

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Assessing Potentials…