If you have only a double pulley, can it be used as a single pulley?

Using a double pulley as a single pulley in a rigging scenario can lead to significant safety issues. If you were to employ a double pulley as a single pulley, there would be the potential for side loading, which occurs when the load does not pull directly down along the axis of the pulley. This misalignment can lead to uneven distribution of forces on the pulley, greatly increasing the risk of equipment failure and reducing the safety of the operation.

In a double pulley setup, the pulley is designed to handle loads in a particular orientation. Side loading compromises the integrity of the pulley and its mounting, which can result in failure. Therefore, to maintain safety and structural integrity, it is crucial not to use a double pulley as a single pulley, as this could adversely affect the entire rigging system.