There is some problem that characteristics of databases differ mutually though there are several current available long-term wave databases. In the previous work, it was clarified that the databases of long-term waves by visual observation have a consistent distortion tendency, and some restoration techniques of them were suggested. In this work, adding some supplements to the previous work, the properties of a long-term prediction of added wave resistance and the midship vertical wave bending moment by using the restored wave databases are investigated.