XD03.13 Industrial Rigging and Signaling Practice Exam

Stability in a lift comes from the weight acting straight down through the lifting point and staying within the support formed by how the sling legs attach to the load. When the center of gravity is directly below the hook and lower than the lowest point where the slings attach, the line of action of the weight remains inside that sling-support region. This keeps the tensions in the slings balanced and prevents any tipping moment, so the load stays level during the lift.

If the center of gravity were higher than the sling attachments or off to one side, the tensions wouldn’t balance evenly and a tipping or side-to-side rotation could develop. If the center of gravity were above the hook, the lift would readily tend to rotate the load instead of staying stable.