If two slings create a 60-degree sling angle to lift a 4,000-pound load and each sling has a rated load of 2,000 pounds, is the per-sling rating correct?

• A. Yes
• B. No
• C. Only if the load is centered
• D. Only with a third sling

Answer: (B)

When two slings share a lift, the load each sling must carry depends on the angle of the legs. The tension in each sling is W / (2 cos theta), where theta is the angle each leg makes from the vertical. A 60-degree angle between the slings means each leg is 30 degrees from vertical, so cos 30° ≈ 0.866. For a 4,000-pound load, the tension in each sling would be 4000 / (2 × 0.866) ≈ 2300 pounds. That exceeds the 2,000-pound rating per sling, so the per-sling rating is not sufficient.

centering or not, the angle is the determining factor here. Using a third sling could change the calculation (e.g., with three slings, T = W / (3 cos theta) ≈ 1540 pounds per sling at 30°), but with only two slings at this angle, the load is too high for the given ratings.