Rigging
The equipment and techniques, such as slings, shackles, spreader bars, and the way they're configured, used to attach a load to a crane or hoist so it can be lifted safely, with the specific configuration chosen based on the load's weight, shape, and balance point.
Why it matters
A load rigged incorrectly can shift, slip, or swing unpredictably once it's off the ground, even if the crane itself is perfectly capable of lifting its weight. Correct rigging is what actually keeps a lifted load stable and under control, which the [[concept-crane-lift-plan|crane's own lift plan]] depends on being right.
On a real project
A rigger selects a spreader bar rather than a simple sling for an oddly shaped steel beam, since a sling alone would cause the beam to tilt unpredictably once it's lifted clear of the ground.
Who this matters most to
An Ironworker frequently works as the rigger attaching structural steel to a crane's hook, choosing the configuration for each specific piece being lifted. An Equipment Operator running the crane depends entirely on the rigger having set up the load correctly before committing to the lift.
Where this goes wrong
A rigger reuses a sling rated for a lighter, more common load on a heavier and differently shaped piece without re-checking the sling's rated capacity for the actual load. The sling fails under a load beyond what it was ever rated to carry, since the substitution was never verified against the load's real weight and shape.