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Flys and Rigging

The fly or rigging systems allows the safe support and quick change of scenery and lighting used in the theatre.

In the past it has normally been a part of the carpentry department.  Now, it is its own separate department with separate, specialized personnel.

The earliest fly operators came from the sailing ship industry, so the majority of the terminology including the term "rigging" comes from sailing ships.

Flown objects can range from curtains, to soft flats, to hard flats, to lighting, sound, and projection equipment.

Counterweight systems


Counterweight system

A metal frame, called an arbor, is raised and lowered by means a long circuit of rope called a purchase line.

A set of wire ropes (usually 1/4" aircraft cable) is attached to top of the arbor. These are the loft lines. The loft lines run through a huge pulley called the head block and then across the grid to smaller, individual pulleys called loft blocks. The cables then attach to a pipe (or batten) on the other end to carry the scenery or lighting. A batten is usually made of 1-1/2" diameter black iron pipe.

The purchase line moves the arbor, and the arbor moves the batten and it's attached load (the scenery, lights, etc.). When the line beneath the arbor is pulled (usually the rear line), it pulls the arbor down, raising the batten. When the other (usually front) line is pulled, it raises arbor, lowering the batten.

Metal counterweights (bricks) are placed on the arbor to balance the load. Bricks come in semi-standard sizes, e.g. 10, 20, 30, and 50 lbs. This weight ideally should exactly balance load on the batten so that the purchase line can pull the arbor both up and down as effortlessly as possible.

Other important components are:

  • Pipe weight - part of the arbor load representing the weight of the empty batten. Pipe weight should be left on the arbor when the load and its counterweight is removed.

  • Trim chains - chain lengths attached to the batten end of lift lines in a counterweight set. Pipe battens at trimmed to level by adjusting these chains.

  • Rope Lock - lever that functions as a brake and lock for the purchase lines to lock the batten at the desired height off of the deck, or to allow the line to move.

Each grouping of the above is referred to as a lineset.

Fly System Types

Counterweight systems come in two main versions: single purchase and double purchase.

Single Purchase

Simple and the more common of the two. The arbor and purchase line travel  between the floor and ceiling with the arbor traveling one foot for every foot the batten travels. When you counterweight, you put the same amount of weight on the arbor as the load weighs.

Everything, travel and weight is a 1:1 relationship.

The main drawback: one entire wall must be dedicated to the system. A full floor-to-ceiling travel of the batten requires a full floor-to-ceiling travel of the arbor. With these systems, the fly operators are located in the wings and at stage level.

Double Purchase

In the double purchase system, the purchase line doubles back through another pulley. The result is that the arbor moves only one foot for every two feet of batten travel, BUT it can therefore be run from a flyrail located halfway to the ceiling, while still allowing the pipe to come in all the way to the floor.

The major drawback is that the double purchase system needs TWICE as much weight on arbor as there is on the batten (2 x the weight, 1/2 the travel).

Loaders (the crew members who load the arbors with weight) typically must handle larger weights.
A single purchase "single" brick typically weights 20-25 lbs.; for double purchase a "single" brick weighs 40-50 lb., and a "half" brick weighs 20 lbs., the same as a single purchase "full" brick.

Announcements Proper procedure for loading battens:

  • Send loading crew to loading gallery (rail)
  • Flyman calls "Heads Up" loudly and lowers the desired, empty batten to the floor
  • Flyman gives clearance to deck crew to hang the load on the batten
  • Crew loads the batten.
  • AFTER the load is on batten, the flyman estimates the total weight and calls up command to the loading gallery to load the arbor with appropriate weights to equal the load
  • Loaders add the required number of bricks, with thin metal spreader plates being inserted between the bricks about every two feet or so in order to better balance the weight.
  • Once the weights are on, loaders lock off the weights on the arbor and call down that the arbor is locked and secured.
  • Flyman calls to deck to "Clear the batten", then carefully unlocks rope and tries to fly goods to see if it is too heavy or too light.
  • If the arbor weight is wrong, the flyman calls corrections up to the loading rail, who adjust the weight accordingly.
  • Once weight is correct, flyman calls "clear the batten" and flies the batten out to trim, locking the rope-lock and securing handle with keeper ring.

To unload, reverse the process:

  • Bring in batten, unload counterweights to batten weight, THEN unload the goods from the batten.
  • Always call "Heads Up" when flying things in and "Clear" when flying things out.