When should the hoist brake be applied during vertical-drop balling?

The correct answer is that the hoist brake should be applied once the ball has finished moving. This practice is essential for maintaining safety and control in the lifting and lowering operations. Applying the brake only after the ball has completed its drop ensures that the load is stabilized before any additional actions are taken, reducing the risk of unexpected movements that can lead to accidents or injuries.

This procedure helps to establish a controlled environment during vertical-drop balling, where the operator can assess the situation without the interference of the moving load. It also allows the operator to secure the load effectively once it is at rest, which is crucial for both the safety of personnel and the integrity of equipment.

The other options suggest applying the brake at various points during the ball's motion, which could lead to instability and potential safety hazards. Such practices could undermine secure handling and increase the likelihood of accidents during lifting operations. Hence, waiting until the ball has stopped moving provides a safer and more effective approach to using the hoist brake.