Why might the boom move back against the boom stops when a load is released at a high boom angle?

When a load is released at a high boom angle, the reason the boom might move back against the boom stops is due to elasticity in the boom and boom hoist systems. Boom systems are typically designed to have some degree of flexibility, which allows them to absorb dynamic forces and reduce shock during operations.

At a high angle, when the load is suddenly released, the tension in the hoist system decreases rapidly. The elastic properties of the materials involved can cause the boom to "bounce" back due to the stored elastic energy. This movement against the boom stops can result from the sudden shift in loads acting on the boom and hoist mechanisms as they transition from carrying the load to being unloaded.

In contrast, mechanical failure would more likely cause complete loss of functionality rather than the specific movement described, wind interference typically doesn't cause movement against stops, and exceeding maximum capacity relates more to structural stress rather than the elastic behavior of the materials. Thus, the characteristics of elasticity in both the boom and the hoist systems adequately explain this phenomenon.