What is the definition of a luffing jib?

A luffing jib is defined as a jib that can change radius and angles independent of the main boom. This characteristic allows for greater versatility when lifting loads, especially in confined spaces or when working at varying heights and distances. The ability to adjust the luffing angle helps to maintain better control over the load, ensuring that it can be raised, lowered, or moved laterally without needing to reposition the entire crane. This makes luffing jibs particularly useful in applications where working around obstacles or adjusting to different vertical levels is necessary.

The other options do not accurately describe the function of a luffing jib. A fixed jib, for instance, does not have the ability to change its angle during operation, which limits its adaptability. Similarly, a telescoping jib refers to jibs that can extend, but this is a different mechanism not associated with the luffing motion. Lastly, while some jibs may be designed for short lifts, the defining feature of a luffing jib is its capability for independent angle adjustments rather than its use case related to lift distance.