Hemp and Sandbag Systems
are one of the oldest forms of stage rigging
. However because they are not as safe as other rigging systems it is rare to see hemp
and sandbag systems in modern theatres.
Despite the drawbacks, there are still certain situations where hemp and sandbag systems are still used, such as when a lineset is not available or as a pick-up point for bridal cables.
The hemp and sandbag system works on the same principal as the counterweight fly system, except it uses sandbags instead of steel counterweights to balance the load on the batten. A similar system is the set system, which still uses hemp ropes, but only carries lite loads and does not need a sandbag counterweight.
One of the major disadvantages of the hemp and sandbag system is that the scenery must first be raised to the grid before the sandbags can be added. This limits the weight of the scenery to what can physically be moved by the rigger(s).
Once the scenery or batten is at the grid, sandbags are added to the other end of the hemp rope to partially counterbalance the system. Because there is no line to pull the scenery down from the grid it must always be slightly heavier than the sandbags.
Once the scenery has reached the proper height, the purchase line is tied off onto a belaying pin on the pin rail.
Another disadvantage of the hemp and sandbag system is the inherent weakness of the rope. Rope systems are subject to more wear and decay than a wire rope and should be inspected before every use.
Note that not all hemp or set systems actually use hemp rope. Many use another organic fiber rope, such as manilla, and some new systems use synthetic kernmantle ropes
Part of the Stage Rigging Metanode