If the safe working load (SWL) of a crane's wire rope is 8,000 lb using one part, what is the SWL when using 4 parts?

The safe working load (SWL) of a crane's wire rope can be determined by understanding the mechanics of lifting with multiple parts. When a crane uses a system with multiple parts of the wire rope, each additional part effectively distributes the load across those parts. This multiplication of parts increases the overall capacity that the crane can lift.

In this case, when one part of the wire rope has an SWL of 8,000 lb, using a block and tackle system that creates 4 parts means that the lifting capacity is multiplied by the number of parts. Therefore, you calculate the new SWL by multiplying the SWL of one part by the number of parts:

8,000 lb (SWL of one part) × 4 (number of parts) = 32,000 lb.

This calculation reflects the increase in the crane's lifting capacity due to the mechanical advantage created by using four parts. Hence, the correct SWL when using four parts of the wire rope will be 32,000 lb.