Without foresight, the marine terminal will usually install a computer system to replace the yard board model when the lack of access becomes intolerable. A computer system gives more people access to the same data without the physical interference problems associated with the yard board model [see Figure 3]. The marine terminal can then effectively continue to add personnel to the tracking effort as the inventory and handling volume increases. However, care must be exercised in selecting a computer system. As this section will show, if the features of the computer system are selected as a knee-jerk reaction to the deficiencies of the paper system, the computer will eventually degrade the overall performance of the terminal.

Concentrate on the Office

Since the obvious source of turmoil and errors is the inventory tracking in the office, the first computer system a marine terminal installs usually addresses only the office needs. In general, these systems are based on printers and forms displayed on CRTs. While solving the access problem, two critical advantages of the yard board paper system are lost:

• The visual nature of the yard board is lost. The container yard can no longer be viewed at a glance; an itemized list of containers on a printout is just not an adequate replacement. At great expense, this disadvantage can be corrected by building an office tower overlooking the container yard. In the tower, planning personnel can overview the actual container yard, instead of referring to a model. Even so, it is said that in an expanding operation, the tower can never be built high enough to see the entire yard. Needless to say, it is difficult to arbitrarily color code the actual containers in the yard.
• Recording the container moves requires an individual to enter the movements into the computer system. For planners untrained in typing skills, key entry is not as simple as the movement of container representations on the yard board.

Unfortunately, all of the disadvantages of the paper system are still maintained:

• The planning still lacks short-term flexibility. Usually, the computer system is still segregated from the yard handling equipment by a paper system. For instance, work lists are entered into the computer by office planners and are printed out and handed to the supervisors for directing the equipment operators.
• Since paper work lists are used, the information in the computer is still not synchronized with the container yard.
• The computer inventory is still prone to errors because moves go unreported.
• Manual inventories and mobile clerks are still required to correct the inventory errors.

Usually, the computer system follows the trend of starting as a simple recording system and then evolves to include the subtle constraints inherent in a yard board model. For instance, eventually the computer ensures that when a container is moved, it is either placed in a empty spot on the ground or in an empty spot on top of another container. If not, the computer will refuse to acknowledge the move. This type of check was visually obvious on the wall board model, but when using paper lists and CRT forms to enter container moves, this check was lost. To compensate, the check must be built into the computer programming.