You are lifting a 3-ton weight with a single whip rove on a swinging boom set at an angle 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 A: 1 3/8 inch. Calculating the precise load on the shackle considering the boom angle factor and single whip tension requires applying standard rigging formulas, yielding a 1 3/8 inch safe working load shackle size.