Ratings, the rated-data rule, and rigging vocabulary

Every load-bearing part carries a working load limit (WLL) — the load it is rated to carry in service — while wire rope is characterized by its ultimate breaking strength (UBS), the load at which it fails. These reference values (shackle WLL by pin size, 7x19 cable UBS by diameter) let a TD sanity-check a rig on paper, but the governing number is always the manufacturer's rated data on the specific hardware in hand: truss load ratings, for instance, live on the sticker and the website, never in memory. Learn the distinction in the forces themselves: a shackle pin sees compressive force, while rope being pulled apart sees tensile force.

The exam is drawn from this material, and you need a perfect score to earn the credential. You can retake it as many times as you need.