Rigging Hitches, Knots, and Lift Planning
Core Concepts
Hitches determine how the sling grips the load. The vertical hitch carries the full rated capacity; the choker hitch reduces capacity (commonly to about 75–80% of vertical); the basket hitch can increase capacity when legs are vertical but loses capacity as the angle flattens. The rigger must match the hitch to the load's shape, weight, and balance, and protect slings from edges and abrasion.
Knots and Termination
Riggers use knots and terminations for tag lines and temporary connections. Know the bowline (a fixed loop that will not slip), the clove hitch (quick attachment to a post or rail), and the round turn with two half hitches. Knots reduce rope strength, so knotted rope is not used for rated lifting. Tag lines control rotation and swing but are never used to lift.
Lift Planning
A lift plan documents the load, the gear, the crane configuration, the path, the personnel, and the hazards. Critical lifts-near capacity, over people or occupied structures, or with unusual configurations-require a more detailed plan and often engineering review. The plan must address the swing radius, exclusion zone, and communication.
Traps and a Rule of Thumb
Traps: assuming a choker hitch keeps full capacity, using a basket hitch without edge protection, and treating a tag line as a load line. Another trap is skipping the plan for a "quick" lift.
Rule of thumb: vertical is strongest, choker is weakest, basket depends on angle-and every hitch needs edge protection and a controlled tag line.