Ports and Infrastructure
The 30 Container-per-Hour Barrier

Breaking the barrier will require multiple factors working together

By Bill Casper, P.E.,
President of Casper, Phillips & Associates, Tacoma, Wash.

Over the past 50 years, container terminals have struggled with a solution that would allow them to increase productivity beyond the 30 container-per-hour benchmark. Efforts have focused on two areas: Ship-to-shore crane productivity and labor productivity. . .

Ship-to-shore crane productivity

One obvious challenge for the dockside cranes has been the increasing ship beams with each new generation of vessels. Not only has this increased trolley travel distance, but the greater ship stability also permitted higher and higher deck loads.
As a result, the percent of on-deck boxes has increased and helped productivity by reducing average hoisting distance. But harbor depth restrictions — which precluded increasing draft in proportion to increased beam — reduced the percentage of below-deck boxes available to cycle in a one‑off/one‑on manner.

Features such as dual hoist cranes, twin lifts and even quad lifts have been implemented to help improve crane productivity. Although this has led to higher and higher hoist and trolley speeds, the gains in productivity have been offset with nearly prohibitive electrical power demands. The capital and maintenance cost devoted to faster cranes has not proven to be a sound investment for most container terminals in achieving increased productivity.

Labor productivity

A Japanese terminal may be able to process 45 containers per hour with the same cranes that American ports use to process only 25 to 30. Longshore labor commonly have been blamed for such disparities. But while labor is a factor, it is certainly not the only factor, maybe not even the most important one.

Increased automation, seen as an answer to labor inefficiencies, has been largely ineffective in breaking the 30 container-per-hour barrier. One reason could be that traditional backland design, be it chassis, strads, RTGs, RMGs or automated terminals, have been intentionally or unintentionally designed to process on average 30 containers per hour per crane through the terminal.

Possible answer—backland operations

Attempts have not done much to improve the traditional terminal productivity of 30 containers per hour.

The answer may lie in viewing the terminal as a system rather than as a series of separate components. When a terminal underperforms relative to its potential system capacity, labor may very well be the one and only reason. But better labor productivity may not make a dramatic improvement in shorter ship turn times if the terminal’s potential productivity as a system has not changed from series to parallel logic.
Minimum ship turn time can only result from a system where the peak capacity of the governing component is always accommodated by surplus capacity in all other components. For example, if cranes are to be the governing components, the backlands have to be designed for peak crane productivity of, say, 50 containers per hour or more. Otherwise this crane productivity can never be utilized unless supported by adequate backland capacity.

Minimum capital cost, not minimum turn time, will result from a balanced terminal system where all components have a small surplus capacity relative to a design capacity. That will tend to compensate for unavoidable downtime in the various “pipeline” components. Are capital and maintenance expenses best focused on the dockside cranes or on the entire terminal as a system, where any component can temporarily go out of service and the slack can be taken up by sister components — and where the governing components are routinely capable of productivity bursts well above their average?

Minimum ship turn time and minimum capital costs are opposing concepts. One or the other is fundamentally set by how well backland planning, equipment and management accommodates the terminal’s crane productivity.