If a bold line is shown on a load chart, the capacities below the line are based on what?

When a bold line is shown on a load chart, it typically indicates capacities that are based on the stability of the crane. This bold line is a visual representation that differentiates between various lifting capacities, particularly under conditions where the crane operates at its maximum load limitations while still ensuring stability. The stability is crucial for safe operation, as it reflects the crane's ability to maintain balance while lifting loads.

The loads indicated below the bold line are determined through specific calculations and testing that account for factors like the crane's center of gravity, the distribution of the load, and environmental conditions. These capacities are critical for operators to understand because they help ensure safe lifting practices.

In contrast, capacities based on manufacturer specifications may vary and include additional factors, while considerations regarding load weight and safety margins play roles in overall lifting strategy but do not specifically relate to what is indicated by the bold line on the chart.