You are lifting a 5-ton weight with a single whip rove on a swinging boom set at an angle of 20° to the horizontal. Use the formula for the size of a shackle with a safe working load and determine the minimum size shackle that should be used to secure the head block to the boom.

Question

Accepted Answer

Option C: 1 3/4 inch. Calculating shackle size involves determining the tension in the whip factoring in the boom angle multiplier. For a 5-ton weight on a 20° boom, mechanical advantage formulas dictate a 1 3/4 inch safe working load shackle.