Scheduling methods used in shipbuilding are unique to each yard and generally reflect practices developed from experience. An overall schedule which is most useful to both management and production departments is one which highlights major tasks and events, and which shows the sequence of work and the relation of the various tasks to each other and to the whole project.
The basic principle in network flow is the task-to-task relationship. That is, task С cannot start until its two prerequisite tasks A and В are completed. There is, of course, the usual task-to-time relationship for each task. These principles have always been employed in one form or another throughout industry, but the computer has now made it possible to utilize to the fullest these principles in network form.
Network Flow Scheduling technique is often used for controlling large, complex, and possibly non-repetitive projects. Examples of the technique are PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method), both of which provide a means of representing graphically the different operations that make up a project. These networks can be revised to show the effects of adjustments to a schedule necessitated by changes in design, delays, etc. It is also possible to treat the network statistically in order to obtain an idea of the probable longest and shortest times for completion of a project.