What is the purpose of a piggyback system in rigging?

A piggyback system in rigging is designed primarily to provide a mechanical advantage independent of the main line system. This means that it allows for the optimization of force applied to a load, making it easier to lift or move heavy items. The mechanical advantage gained from this type of system is crucial in situations where lifting heavier loads is required, as it reduces the amount of physical effort needed from the rigging operators.

In a piggyback setup, additional pulleys or blocks are used to multiply the lifting force. This is particularly beneficial in complex rigging operations, where efficiency and safety are key concerns. By having this independent mechanical advantage, the rigging team can control loads more effectively, enhancing both the speed of operations and safety measures in place.

The other options relate to different aspects of rigging but do not capture the specific function of the piggyback system. For example, while tying knots and securing loads are critical components of rigging, they do not involve the unique mechanical advantage aspect that defines a piggyback system. Similarly, a safety harness plays a vital role in worker security but does not pertain directly to load movement mechanics.