Rigging 101: Judging the Weight of the Load
When you don’t know the weight of a drop, a piece of scenery, or the lights you’re loading onto a batten, how do you determine what the load actually weighs?
It may seem like reverse engineering, but the best way to figure out the weight is to load the batten and the arbor until the two are in balance. Here’s how:
As you load or unload counterweights, feel the system by seeing which side of the hand line is in tension. When a set is in balance, both lines have the same amount of tension, and they move fairly easily. Once you have balanced the load, you can count the counterweights to get a rough weight.
Keep these basic issues in mind as you work with your counterweight rigging system:
- Know your load limits. Each line set has a specific load capacity; make sure these are written on the batten end caps and on the index cards under each rope lock at the lock rail. Do not exceed these limits, as they can affect the structure of your building.
- Train and authorize the operators. Keep a log that details which of your staff members and volunteers have had official training on use of the rigging. Choose one of these people to supervise rigging operation during productions.
- Determine the permanent counterweight. Identify the empty trim (pipe) weight for each batten, so the trim weight will not be mistakenly removed. Every set will have permanent counterweight on the arbor to balance the empty batten. Consider painting these permanent weights red or yellow, to signal that they should not be removed from the arbor. Strapping them in place with flat metal bands or cable ties is also a good idea.
- Keep weights in neat stacks at the side of the loading gallery—but no higher than the toe boards at the bottom of the gallery. This will keep operators from accidentally kicking them off the bridge.
- Don’t overload the gallery. There should be a sign on the gallery to tell you how much load the bridge will carry.
- Keep your mind on the job. Make sure a responsible adult is in charge of the counterweight system, and keep distractions to a minimum backstage.
- Wear heavy-duty work gloves and closed, hard shoes. Fingers and toes can be in peril during any production.
For more information—especially for the least experienced members of your crew—click here. You’ll find manuals for your counterweight rigging system, information about fire curtains, instructions on the operation of controllers for automated rigging, and much more. There are even signs available that you can post backstage to help remind your rigging operators of basic steps to take for safety.
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