It is well known that, about 70-90% of the total drag of a ship is due to the viscous effects. Large amount of theoretical and/or experimental studies on the topic have already been performed. More studies are needed, however, to develop efficient numerical methods which are useful for practical ship design. The present study deals with the theories and numerical methods essential for understanding of real fluid characteristics. Actual ships are not considered because enough computer capacities were not available at the time. Numerical methods, however, are developed to describe complicated ship geometries, transition processes and turbulent boundary layers. The present study can serve as a good start for estimations of viscous ship resistance if an high speed computer is available.