Boom Hoist Rope Damage and Field Splice Proposal
During a pre-shift inspection of a 30-ton crawler crane, the operator finds the boom hoist wire rope has a tight kink about 18 ft behind the drum, a birdcage deformation 4 ft from the kink, and two broken wires in one outer strand within one lay. The rope is 3/4 in, 6×19 IWRC, and the sheave grooves show visible wear with a sharp edge. The hook has a missing safety latch, and the load line has a slow oil leak at the swivel. The crane was last annual inspected 13 months ago; the log shows the rope was replaced 8 months ago. The operator wants to cut out the damaged 20 ft section and splice the rope with two wire rope clips to finish the day's two lifts.
1. Which findings require removal from service, and why is cutting out the damaged section and splicing with wire rope clips unacceptable?
Read the worked answer
The tight kink and the birdcage are immediate removal criteria for a running wire rope; they show permanent distortion and lost strength. The two broken wires in one outer strand are below the three-in-one-strand threshold by themselves, but they confirm the rope is deteriorating. The missing hook latch, worn sheave with a sharp edge, oil leak, and overdue annual inspection also make the crane unserviceable. Cutting out 20 ft and joining the rope with two wire rope clips is not acceptable for a boom hoist rope; field splices and clips are not a manufacturer-approved termination and can fail under repeated bending. Replace the rope.
2. What must be done before the crane returns to service, and what records should be kept?
Read the worked answer
Lock out and tag out the crane. Replace the boom hoist rope with the manufacturer-specified rope and termination, and inspect the sheaves for groove wear and sharp edges; replace or re-machine per manufacturer. Replace the hook latch, repair the swivel leak, and have the crane re-inspected by a qualified person. Because the annual inspection is 13 months old, complete the periodic inspection before returning to service. Record the rope replacement, sheave inspection, repairs, and inspection results in the maintenance log, and keep the removal report for the rope.