What signal should be given when the load must remain at a constant elevation and move horizontally closer to the crane?

When it is necessary to maintain a constant elevation of the load while moving it horizontally toward the crane, raising the boom and lowering the load is the appropriate action. This approach ensures that the load remains at the desired height while allowing for the horizontal movement required.

By raising the boom, the angle of the crane arm increases, effectively lifting the load higher off the ground. At the same time, lowering the load while keeping the boom elevated allows for the load to be repositioned horizontally without changing its vertical position. This coordination is crucial in crane operation to avoid accidents and maintain precise control of the load.

Other approaches, such as lowering the boom with the load raised, may complicate the lifting dynamics and could inadvertently change the load's elevation. Additionally, simply lifting while turning the load might not keep the load horizontally moving closer to the crane effectively. Adjusting heights while moving could also result in the load losing its stable position, which could be hazardous. Thus, raising the boom and lowering the load is the safest and most effective technique for this scenario.