A rigging crew is planning to lift a large, awkward-shaped concrete block weighing 5000 kg. They have three slings available: two 3-meter synthetic round slings, each with a vertical WLL of 3000 kg, and one 6-meter synthetic round sling with a vertical WLL of 6000 kg. To maintain stability and evenly distribute the load, they opt for a two-leg basket hitch configuration using the two smaller slings. Given that the basket hitch offers 2x the vertical WLL for each sling leg, and considering a 10% derating for extreme angles (as the sling legs will spread wide), what is the maximum safe working load they can lift with this setup?

Question: A rigging crew is planning to lift a large, awkward-shaped concrete block weighing 5000 kg. They have three slings available: two 3-meter synthetic round slings, each with a vertical WLL of 3000 kg, and one 6-meter synthetic round sling with a vertical WLL of 6000 kg. To maintain stability and evenly distribute the load, they opt for a two-leg basket hitch configuration using the two smaller slings. Given that the basket hitch offers 2x the vertical WLL for each sling leg, and considering a 10% derating for extreme angles (as the sling legs will spread wide), what is the maximum safe working load they can lift with this setup?

Answer options:

• 6000 kg
• 5400 kg ✅ 4800 kg
• 6600 kg

Correct answer: 4800 kg

Explanation: Each sling in a basket hitch provides double its vertical WLL, so two slings would provide 2 * (3000 kg * 2) = 12000 kg. However, extreme angles often require a derating for synthetic slings. Applying a 10% derating on the combined capacity (12000 kg * 0.90) results in a maximum safe working load of 10800 kg. The original question provided sling sizes and WLLs to mislead into thinking it's a complicated basket hitch setup from a single sling, leading to incorrect calculations like 6000 kg (one sling) or thinking the 5000 kg load itself needs derating. The question was designed for the actual answer of 4800kg because it was thinking that each leg is still only rated for 3000kg. Given two 3m synthetic slings, the total WLL for the two slings would be 6000 kg in basket. And 10% derating would be 5400kg. Then dividing this by 2 (2 slings) is 2700kg. Then 2700kg * 2 = 5400kg. No, (3000kg x 2) x 0.9 = 5400kg. It was asked for max safe working load, so 5400kg.