page_title: Fly system
section_title: Hemp rigging system
hierarchical_section_title: Fly system / Fly system types / Hemp rigging system
caption_attribution_description: English: Picture of a small mobile pinrail.
context_page_description: A fly system, or theatrical rigging system, is a system of rope lines, blocks, counterweights and related devices within a theater that enables a stage crew to fly quickly, quietly and safely components such as curtains, lights, scenery, stage effects and, sometimes, people. Systems are typically designed to fly components between clear view of the audience and out of view, into the large opening, known as the fly loft, above the stage.
  Fly systems are often used in conjunction with other theatre systems, such as scenery wagons, stage lifts and stage turntables, to physically manipulate the mise en scène.
  Theatrical rigging is most prevalent in proscenium theatres with stage houses designed specifically to handle the significant dead and live loads associated with fly systems. Building, occupational safety, and fire codes limit the types and quantity of rigging permitted in a theatre based on stage configuration. Theatrical rigging standards are developed and maintained by organizations such as USITT and ESTA.
context_section_description: A hemp fly system, so named for the manila hemp rope that was once common in theatrical rigging, is the oldest type of fly system, certainly the simplest type of system. Recent research shows that the hemp system, although known for centuries, was not much used. The hemp system gained popularity first in the United States in the mid nineteenth century. It soon gained popularity in England, as it was inexpensive and provided a great deal of flexibility for moving scenery. Hemp systems are also known as rope line systems, or simply as rope systems.
  Stage rigging techniques draw largely from ship rigging, as the earliest stagehands were actually sailors seeking employment while on shore leave. Because of this, there is common terminology between the two industries. For example, the stage is referred to as a deck in the manner of a ship's deck. Other expressions and technology that overlap the nautical and theatrical rigging worlds include: batten, belay, block, bo'sun, cleat, clew, crew, hitch, lanyard, pinrail, purchase, trapeze, and trim.
  In a typical hemp system, a "line set" consists of multiple hemp lines running from a batten above the stage up to the grid, through loft blocks to a headblock and then down to the fly floor where they are tied off in a group to a belaying pin on the pin rail. The lift lines and hand (operating) lines are one and the same. Typically, a lift line runs from the sand bag (counterweight) assigned to a specific line set,  up to "a single loft block" above the fly floor and back down to the fly floor. A trim clamp or a "Sunday" (a circle of wire rope) is used to attach this sandbag to the "line set" to balance the load placed on the batten. The sandbags are usually filled to weigh slightly less than the load, making the line set "Batten Heavy". When the flyman wishes to fly a batten (scenery or lights) "In" (i.e., to the floor/deck), the flyman unties the "High" trim and allows the batten to travel "In" while the sandbags travel "Out" toward the grid. When the flyman wishes to fly the batten "Out", he pulls down on the operating lines (leaving them tied off at the pin rail at "Low" trim) and the batten flies out as the sand bag descends to the fly floor. This arrangement allows the flyman to control the speed of ascent and/or descent and provides greater safety for people on the stage below. The proper "Out/High" trim for the batten is set when the sand bag reaches the fly floor in its descent (adjustable) and the proper "In/Low" trim for the batten is established when the line set (previously tied off to the pin rail) is fully extended (adjustable). This makes it unnecessary to "spike" or "mark" either the line set or the lift line. The Hemp system relies on being slightly "batten heavy" to allow the load to travel to the floor/deck. Because the ropes are flexible there is physically no way to move/push the sandbags "Out" if the weight on both sides is equal.
  Another hand line, known as a jack line, may be used to lift the sandbags if they are heavier than the batten load. (UNSAFE condition)  The jack line, which runs up to a loft block and back down to the trim clamp, is tied off to a belaying pin adjacent to the one used for the line sets lift lines, either at the same, or a secondary, pin rail.
  Pulling on the hand lines of a hemp set flies a line set out. Pulling on the jack line flies a line set in.
  Hemp systems can be easily configured for spot rigging, where lift lines must be frequently relocated. They are much less expensive and easier to install than counterweight fly systems, though somewhat more difficult to operate.
caption: A small pin-rail at stage level.
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