Rigging & Hoisting
Sling hitches, shackles, spreader beams, choker capacity, and crane signals.
- Identify the three basic sling hitches and their capacity reductions
- Select appropriate rigging hardware including shackles and spreader beams
- Demonstrate standard crane hand signals
Lesson 1
Sling Hitches & Capacity Reductions
The Three Basic Hitches
Every rigging operation uses one of three basic sling configurations. The type of hitch determines the sling's effective capacity compared to its rated straight-pull (vertical) capacity.
Vertical Hitch
Capacity: 100% of rated load
Sling goes straight up from the load
Simplest hitch, no angle reduction
Choker Hitch
Capacity: 75% of rated load
Sling wraps around load, passes through eye
Most common for loose bundles
Basket Hitch
Capacity: Up to 200% of rated load
Sling cradles the load, both eyes to hook
Load must be balanced and stable
Sling Angle Effects
When slings are used at angles less than vertical, the tension in each sling increases. The smaller the angle from horizontal, the greater the tension. The sling angle factor reduces the effective capacity as the angle decreases.
Never Rig Below 30 Degrees
Sling angles below 30 degrees from horizontal are prohibited. At low angles, sling tension increases dramatically and the load becomes unstable. At 30 degrees, each sling carries twice the vertical load.
A choker hitch reduces capacity to 75% of rated load. A basket hitch can double capacity to 200%. Never rig at sling angles below 30 degrees from horizontal.