Deflection of the boom and pendant stretch will increase which of the following?

• A. Load (swing) radius
• B. Lifting height
• C. Boom length
• D. Counterweight load

Answer: (D)

When the boom deflects and the pendant stretches under load, the line of action of the lifting system shifts and the load creates a larger overturning moment about the crane’s base. To keep the crane balanced and prevent tipping, the counterweight must provide a greater resisting moment, so the counterweight load increases. The other factors—load swing radius, lifting height, and the physical boom length—don’t inherently rise just from deflection and pendant stretch, since they’re determined by different aspects of the crane’s geometry and operation.