I would like to give a very big thank you to Jay Glerum and the Stage Rigging handbook for making sure the information below is correct.
A counterweight rigging system is a step above a Hemp Rigging system. The two different types of counterweight systems in use in theatres today are Single-Purchase, and Double-Purchase counterweight systems.
[h2]Single-Purchase Counterweight System[/h2]
A Single-Purchase Counterweight System is used in theatres when you have a clear wall available to run from ground to ceiling on one of the sides of your stage. The distance you pull on the rope will be the amount that the batten moves on a single purchase system. When weighting a Single-Purchase system your ratio of weight on the batten to weight on your arbor is 1:1.
[h2]Double-Purchase Counterweight System[/h2]
A Double-Purchase Counterweight System is commonly used when you need space under where your fly system is run from. The location of a Double-Purchase fly rail is generally half way between the stage floor and the grid. The way that a Double-Purchase system moves two feet on the batten for every one foot pulled on the hand line. Due to the difference in movement the weights on the arbor are two times the amount of weight that is on the batten.
Wire rope is a great improvement over hemp for use in rigging systems since wire rope doesn't shrink or expand with humidity changes like hemp rope can. Wire rope is also much stronger than hemp and has a lower profile than wire rope.
[h3]Properties and Construction of Wire Rope[/h3]
Reserve strength: The ratio of outer wires to inner wires.
Flexibility: Wire rope is flexible, it bends around sheaves or anything else it needs to wrap around.
Strength: The main interest when selecting wire rope is the strength of the rope. When working theatre you want to select a wire rope that has a design factor of 8:1 (or where the maximum weight that will be supported by the line is 1/8th the breaking strength)
[h3]Grades of Wire Rope[/h3]
(below is a chart showing a comparison of 1/4" wire rope breaking strength)
- Plow Steel
- Galvanized Aircraft Cable
- Extra Flexible Wire Rope
- Rotation-Resistant Wire Rope
- Sash Cord
- Tiller Rope
[h3]Signs of Wear[/h3]
- Sash Cord: 2,040 lb
- Tiller Rope, Plow Steel: 2,620 lb
- Plow Steel IWRC: 4,780 lb
- Improved Plow Steel IWRC: 5,480 lb
- Extra Improved Plow Steel IWRC: 6,800 lb
- Galvanized Aircraft Cable: 7,000 lb
When you run an inspection of your system always look for signs of wear on the wire rope, this includes but is not limited to; broken wires, flattened wires, separation in wire, rust, signs of chemicals, or anything that doesn't look right.
Any signs of wear in a theatre application should be replaced immediately!
The location of operation of the fly system. The Lock is what holds the line from moving when not in use. The lock is not designed to be used for holding heavy weights when loading a batten or arbor.
The Arbor is where the weights for balancing the system comes into play. The weights are stacked on the arbor and spreader plates and lock plates (locking collars or locking rings) help to hold them on the arbor for safety. *During a runaway the lock plates and spreader plates may not save the weight from flying out of the arbor*
The Hand Line is what the operator of the fly system uses to move the batten up and down. Or into the deck and out from the deck. This rope should be taught, if the rope is loose it should be adjusted so that it is in tension again.
This is the location where weights are loaded onto the arbor. This is usually around 2/3rds of the way between the fly rail and the grid. Not every system has a loading bridge.
When loading weights you want to make sure that the weight is placed on the arbor in a way that it will not shift or fall off when the system moves. Loading and unloading is easiest to do when you have two people working on a single line. one working directly with the arbor and one person handing the weight to the person loading the weight.
[h4]Using a Loading Bridge[/h4]
Loading weights can be very dangerous. Before working on the weight rail observe and learn from an experienced trainer on how the procedure in the specific space is to be done.
When using a loading rail there are jobs on the fly rail as well as the loading rail to insure safety of everyone involved.
First the rail operator must make sure the line is secure and not going to move while they are loading weight. This can be achieved by a couple different methods:
Loading the weight should be done in an order to keep from having anything running away.
- Twisting the Hand Line
- Tie a safety hitch from the hand line to the Fly rail
- Use a Line Lock
- Use a Bull Line
- Use a Bull or capstan winch
This order is a safe order to load a batten and weight the system:
To unload weight and empty a batten this order is a safe way:
- Load the Batten
- Load the Arbor
- Check Weight
- Adjust Weight
- Clamp down weights with weight locking plate (collars)
[h4]Without a Loading Bridge[/h4]
- Unload Arbor
- Unload Batten
- Clamp down remaining weights with weight locking plate (collars)
When you don't happen to have a loading bridge you have to do a longer process in order to be able to move heavy loads without the system becoming out of control
This is done with a partial weight procedure.
- Load a small amount of weight on the Arbor, enough to make a difference but not too much that the operator can't lift it.
- Add some of the load to the batten
- Add more weight on the arbor
- For unloading just reverse the procedure, removing all weights or the full load can result in a runaway.
- Clamp down weights with weight locking plate (collars).
When moving a batten during calls or non show situations, communication is key to keep from anyone being hurt.
Before moving any lineset yell a warning "Lineset #_____ (coming in/going out)"
A "thank-you" is appreciated from anyone on stage at the time so that it has been made clear that everyone knows what is going on.
Before loading weight, call out a warning "Loading weight on Lineset #____"
A "Thank-you" is also appreciated here as well, so we know that people are standing clear of any potential problems.
If a line set starts moving on its own, commonly cause of out of weight lines, it is called a run-away. DO NOT TRY TO STOP THE RUNAWAY!!! The amount of weight that is moving through the space at the time is too fast and the forces involved will not be stopped by the lock or a hand on the line... When this happens you want to yell "RUNAWAY" and get as far away from the stage and find cover. There is no need for a thank-you for this, just run and get to a safe far place from the fly rail or stage.
If the flyman operating the linesets does not have a direct line of sight to the stage, it may be necessary to have someone onstage calling out instructions to the flyman as the batten is flown in. Only one person should call out instructions to the flyman to prevent confusion and accidents. Ideally the stage should also be quiet so that the flyman can clearly hear the callers' instructions.
[h4]Setting the Trims[/h4]
A batten is trimmed by bringing it to a predetermined height above the stage. There are 4 types of trim heights; 'grid,' 'work,' 'show' and 'out.'
Battens that are on unused linesets are flown as far up as they can go, usually all the way to the grid it is hung from (or the ceiling if there is no actual grid). This is being at grid height.
Battens that are being worked on (i.e. an electric that is getting hung/circuited, or a scenic pipe getting a flat hung on it) are flow in to 'work' height. The batten is flown all the way in until it is just a few feet off the deck so that it is easy and accessible to work on.
The 'show' trim is a battens' height above the stage when it is being used/seen during the show. The 'out' trim is a battens' height above stage when it is not being used/seen during the show. Typically when the batten is at its 'out' trim it is brought just high enough so that whatever is hung from the batten can no longer be seen from the audience. Often this means that there is still room in the system for the batten to fly out higher, but flying it out higher would add unnecessary time to bring it to its 'in' height.
When a batten is set to its trim, a flyman works the rail while someone stands on stage calling out instructions to them. The flyman calls out which lineset is moving and then slowly moves it in our out. The stage hand calling-out instruction uses a tape measure (or their eye) and as the batten approaches trim height they call out a warning to the flyman to slow down, and then they call out to him to stop. Often the most effective way is to call out as the trim is approaching, 'three feet, two feet, one foot, stop.' This gives the flyman enough time to slow down and stop.
Showtime opperation for a fly system can be fun. To make sure that nothing goes wrong you want to go through and check everything in your system by labeling, testing, and making sure everyone understands how cues are going to be called.
Labels are what makes a system clear to operate and makes sure what you are moving is what needs to be moved or is safe to move.
Also having trim marks as to where things fly in to and out to is key for safe operation, warning marks are also handy when things have to fly in fast.
When labeling the in spike mark or the out spike mark, make sure the person who will be operating the line is doing the marks and the marking system is consistent throughout. If i am making a spike mark at the lock level, then everyone is going to do that. If i am going to make a spike mark so that it is on the two lines and when they line up horizontally that's the spike, then everyone does the same thing. Consistency is key in fly systems.
Make a Habit of Testing your equipment before each show, to make sure everything is in weight and that you know your in spike and out spike are still clear and still at the right location. If something feels different, find out why.
Cueing from the Stage Manager should be clarified and understood by everyone on the fly crew. If they want a response when they say standby make sure your crew replies when they are standing by.
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