The large first cost and subsequent operation and maintenance costs of sea-level canals demand that all economic and technical alternatives be thoroughly investigated before construction is begun. The vast number of variables to be considered for any given set of alternative canals requires study in an orderly and meaningful manner. An analytical model in the form of a digital computer program to predict ship transit calculates ship movements by evaluating, at small, equal time increments, the many changing factors which affect their movement. In addition to inserting ships into the canal in some prescribed order, the program keeps track of each ship (its type, location, speed, and direction) in the canal and adjusts its speed at each time increment so that each ship operates safely under a predetermined set of conditions. The program is designed to predict the number of ship transits per unit time by considering the canal configuration, flow conditions in the canal, and the shipping which is expected to use the canal. The program can be used to optimize canal configuration for any given expected shipping, to optimize the manner of ship input for a given canal configuration, and to develop operation procedures for any canal configuration with any ship mix. (Author).