What is a main drawback of lifting a load with one sling in a single vertical hitch?
- The sling loses about half of its rated capacity
- The load is free to rotate and hard to control
- The sling tightens and crushes the load
- The load angle factor rises above 2.0
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B. The load is free to rotate and hard to control
A single vertical leg gives no resistance to spinning, and rotation can also unlay a wire rope sling. The sling keeps its full vertical rating in this hitch, so loss of capacity is not the problem; control is.
Reference: Rigging principles: vertical hitch
Compared with the same sling used in a vertical hitch, its rated capacity in a choker hitch is:
- Higher, because the sling grips the load
- Doubled, because two parts of it carry the full load
- The same, because one leg carries the load
- Lower, because the sling bends sharply at the choke
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D. Lower, because the sling bends sharply at the choke
The sharp bend where the sling body passes through the eye concentrates stress, so the choker rating is less than the vertical rating. Doubling applies to a basket hitch with vertical legs, where two parts really do share the load.
Reference: Rigging principles: effect of hitch on capacity
A sling is rated at 4,000 lb in a vertical hitch. With an adequate D/d ratio and both legs hanging vertical, about what is its capacity in a basket hitch?
- 4,000 lb
- 3,000 lb
- 6,000 lb
- 8,000 lb
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D. 8,000 lb
With both legs vertical, two parts of the sling each carry up to the vertical rating, so the basket rating is twice the vertical rating: 8,000 lb. The figure drops as the legs spread from vertical or if the sling bends around too small a diameter. A value below 4,000 lb would be typical of a choker, not a basket.
Reference: Rigging principles: effect of hitch on capacity