Theatre Design & Technology - Spring 2021 - 21

hether renovating an old counterweight rigging system or planning
to install a new one, consider the total cost of ownership over the price
of the initial investment. A major

factor in the total cost of ownership is how long it will
last before needing maintenance or replacement. Thus,
a focus on where the investment will do the most good
and provide the most longevity can result in substantial
savings over the long-term. Most importantly, this investment should be guided by a strong collaboration between
consultant, owner, architect, manufacturer, installer, general contractor, and the users.

Although I have, for some time, suggested that a counterweight line set
should operate with very little friction,
I did not really expect it to be a reality. But I found the unicorn in January
2020 at the Imperial Theatre in St. John,
New Brunswick, Canada. Shawn Lord,
the technical director of The Imperial
Theatre, engaged me to inspect the counterweight rigging system. He expected
that their 27-year-old system, for which
he had no record of inspections, would
be " nearing the end of its usable life. " The
inspection was the first step in planning
for the system's replacement. Instead, I
realized I was inspecting one of the best
counterweight rigging systems I have
ever encountered. What was so special
about this 27-year-old system?
First, the force needed to initiate
movement of the line set was minimal.
Second, the force needed to keep the line
set running for the entire length of its
travel was minimal. Third, when starting
at either end of travel, the force required
decreased until mid travel, after which

the line set wanted to run by itself.
It was like there was no friction in the
line set for its entire length of travel. How
can it be? If one must exert force to keep
a line set running, then the system is encountering friction, a force that resists
relative motion between two materials.
What causes the friction in the system?
Why is there so little in this one? Let's
explore.
There are a number of potential
causes of friction in a counterweight line
set: the block set, the arbor shoes, rope
groove sizing, pitch diameter at the head
block, and the rope lock. Other factors
include surface roughness, adhesion,
or imperfections in the system components. The arbor shoes could be rubbing
on the guides. This could be the result
of the guide wall out of plumb and being not true. It could also be a result of a
misalignment of the head block with the
guide wall.
Or, the block set can inflict friction into
the lineset for any of a number of reasons.
The fleet angles of the lift lines as they

From the author:
As I travel and visit theatres
looking at their counterweight
systems, I often ask the
technical director if I can run
one or two line sets, always
empty ones. I run them from
one end of travel to the other
and back. When I first started
asking to do this, I felt kind
of awkward because I didn't
really know what I was looking for. Eventually, however, I
began to notice differences
among the systems. At first,
I made mental notes about
how the line sets operated,
the level of friction or resistance, and how easy or difficult it was to move them.
Eventually, I developed a
detailed checklist with key
benchmarks.
To date, I have run many
line sets in many theatres.
They were built by multiple
manufacturers and installed
by many vendors. The ages
of the line sets have varied
from brand new to one dating
back 116 years. I've operated
systems made by Wenger/
JR Clancy, Thern, Knoxville
Scenic, SECOA, Peter
Albrecht, Sosman and Landis,
Channon, United Stage
Equipment, and many more.
They have been American,
Canadian, German, Italian,
British, Spanish, French, and
homemade. They all operated
differently. Some were better
than others. Eventually, I realized that I was on a quest to
find the perfect system. That
quest ended with the Imperial
Theatre in St. John, New
Brunswick, Canada.

SPRING 2021 | THEATRE DESIGN & TECHNOLOGY

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Theatre Design & Technology - Spring 2021

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