In the design of port facilities, the specification of the target ship is one of the major conditions. The target vessel is the largest of the vessels assumed to use the facility. If the target ship is specified in advance, the specifications should be used for the design. If the target ship is not specified in advance, the ship specifications must be calculated from the ship type and scale (DWT/GT) of the target ship. At that time, where to set the degree of reliability with respect to the size of the ship should be decided according to the characteristics of the port facility, the usage situation, the natural environment, and so on.
　In this study, we propose a method to calculate the ship specifications with arbitrary reliability from the ship type and scale of the target ship. Draft, wind pressure projected square area (fully loaded/ballasted), and wind pressure projected side area (fully loaded/ballasted) were calculated. The ship data used in this study are mainly from Lloyd's Register of Ships (1995.6).