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Understanding Container Handling Statistics
Greg Baker
Statistics Group
12 May 1998
There is a large number of measures which can be used to assess Australia's
waterfront performance.
Important among these measures are what the Bureau of Transport and Communications
Economics (BTCE) -now the Bureau of Transport Economics-calls stevedoring
performance indicators and the Productivity Commission calls capital
productivity measures.
In the context of container freight these indicators have been an integral
part of the current dispute on the waterfront.
How are these indicators defined? How have the indicators moved since
the recent waterfront reform process began with the establishment of the
Waterfront Industry Reform Authority (WIRA) in 1989? Are these indicators
internationally comparable?
To understand the statistics it is necessary to be aware of some of the
factors used in the measurement of productivity.
Container sizes
Standard shipping containers are specified by the International Standards
Organisation as 20 feet long by 8.5 feet square. These are the standard
unit for measuring container throughput-one such standard container is
1 twenty-foot equivalent unit or 1 TEU.
Other containers such as those that are 40 feet long by 8.5 feet
square can be counted as equivalent to a number of TEUs; forty-foot containers
are equivalent to 2 TEUs. Non-standard container sizes can also be
measured to give a TEU value for use in calculating statistics.
Ports
Australian stevedoring data are regularly published by BTCE for the five
major Australian ports-Brisbane, Sydney, Melbourne, Adelaide and Fremantle.
In addition statistics are published as averages of these five major ports;
the statistics presented in this note are such averages.
Time
The measured rate at which containers are moved depends not only upon
the number and size of containers moved but also on the time that cranes
are able to work a ship.
Elapsed time is the total time over which a ship is worked measured
from first labour aboard to last labour ashore.
Gross time is the elapsed time less the time that the ship is
unable to be worked due to ship's fault, weather, awaiting cargo, industrial
disputes, holidays or shifts not worked at the shipowner's request.
Net time is the gross time less award shift breaks.
Container movements-TEUs
There are two measuring units in general use that indicate waterfront
productivity in terms of the throughput of containers.
The first-and one which has been measured in Australia since 1989-is
to form the measure in terms of the number of TEUs handled.
There are three measures based on calculating the number of TEUs per
hour and used by the BTCE-the crane rate, the elapsed rate and the net
rate. The crane rate is a measure of productivity per crane; the other
two rates are measures of productivity per ship handled.
The crane rate is defined as the number of TEUs moved per net
crane hour.
The elapsed rate is the number of TEUs moved per elapsed hour
regardless of the number of cranes working the ship.
The net rate is the number of TEUs moved per net hour regardless
of the number of cranes working the ship.
Because net time never exceeds elapsed time the elapsed rate will never
exceed the net rate.
Figure 1 shows that the average crane rate has increased from below 14
TEUs per hour in 1989 to around 23 TEUs per hour in 1997.
The same figure shows that the net rate has increased from around 16
in 1989 to 31 in 1997 and the elapsed rate has increased from 14 to 26
TEUs per hour over the period.
Note that data are not available for the period December 1992 to June
1993 which is the period after WIRA was concluded and before BTCE began
to collect these data. Note also that there are breaks in the consistency
of the series in September 1993 and March 1997.
The disadvantage of using measures based on TEUs, particularly when the
aim is to form international comparisons, is that these statistics can
be affected by the mix of twenty-foot and forty-foot containers. Many
large overseas ports have a high proportion of forty-foot containers and
all other things being equal will show higher crane rates than Australian
ports with a lower proportion of forty-foot containers.
In addition the change in mix of twenty-foot and forty-foot containers
in the period since 1989 means that even Australian statistics are not
strictly comparable over this period.
Container movements-numbers
Using the second unit of measure of container movements can overcome
to some extent the deficiency that the TEU measure is affected by the
mix of twenty-foot and forty-foot containers.
This measure simply counts the number of container movements per hour
regardless of the size of the containers.
As with the TEU measures it is possible to define three indicators for
container movements also called the crane rate, the elapsed rate and the
net rate.
These latter BTCE measures, however, have only be available for Australian
ports since December 1995 and Figure 2 shows the crane rate, the elapsed
rate and the net rate since then.
In the period the crane rate has increased from below 16 to more than
18 container movements per hour; the elapsed rate has increased from below
18 to above 20 movements per hour; and the net rate has increased from
below 21 to above 24 per hour.
International comparisons
While these indicators are useful to show changes in waterfront productivity
over time they need to be treated with caution if used to make comparisons
with waterfront productivity in overseas ports.
A Bureau of Industry Economics study International Benchmarking-Waterfront
1995(1) shows for 1994 that cranes at a number of overseas ports were
able to achieve in excess of 25 container moves per net hour. This at
first sight appears vastly superior to the best Australian figure of 18.5
container movements per hour for example for Fremantle in the same period.
Similarly the Productivity Commission 1998 study International Benchmarking
of the Australian Waterfront(2) shows a number of overseas ports exceeding
Australia's net crane rate measured in lifts per hour.
However, although overseas ports would be seen on average to have higher
crane rates, these figures are a function of which trade is considered-in
the South-East Asian trade for example Fremantle crane rates exceed those
of Singapore.
Overall it can be seen that it is very difficult to use these stevedoring
productivity indicators for strictly accurate comparisons with overseas
ports.
Indeed it is even difficult to compare figures from different Australian
ports and over time.
There are several factors underlying this and it is not known how these
factors vary from shipping trade to shipping trade and over time.
One factor is that in Australian circumstances in which ships are more
likely to offload at a multiple of ports these indicators are dependent
upon the efficiency of the way ships are stowed. If containers are well
arranged the loading and unloading task will be simplified and hence more
efficient.
Another is that these measures may be dependent on the percentage of
the entire ship's cargo that is handled at any particular port. In this
context note that it is in general more efficient to exchange the entire
container cargo of a ship than it is to exchange only a proportion of
it.
Yet another is that the measured values are dependent on the characteristics
of the ships being loaded and unloaded and of the ports. More modern and
better equipped ships and ports will in general lead to easier load and
unloading.
- Bureau of Industry Economics, International Benchmarking-Waterfront
1995, Report 95-16, AGPS, Canberra, August 1995.
- Productivity Commission, International Benchmarking of the Australian
Waterfront, Research Report, AusInfo. Canberra, April 1998.
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