What is the primary purpose of a roster sheave or auxiliary boom point sheave?

The primary purpose of a roster sheave or auxiliary boom point sheave is to separate the hoist line. This component helps guide the hoist line more effectively, allowing for better management of the load being lifted. By utilizing a sheave in this manner, it reduces the chances of the hoist line becoming tangled or creating excessive wear on the line itself. Proper separation of the hoist lines is critical for maintaining effective operation, optimizing lifting efficiency, and ensuring safety during crane operations.

This functionality does not primarily focus on increasing load capacity, enhancing stability, or creating backup systems, which are considered secondary benefits. For instance, while a well-maintained hoist line can contribute to improved stability, the direct role of the sheave is specifically to manage the lines rather than to serve as a stability mechanism.