Newman-Sharma's wave analysis method is one of the most rational and practical method for its mathematical explicitness and simplicity of experiment. However, the accuracy of wave measurement and analysis sometimes becomes an issue when it is applied to separation of resistance components, hull form design and so forth. In this paper, in order to investigate the basic problems of Newman-Sharma's method, the author presents the results of extensive experiments with INUID ship model, which was made in two tanks of IHI Ship Model Basin, the towing tank and the seakeeping & maneuvering tank which has a wide area of water surface. Main object of these experimental investigations was to cast light upon the indistinct influences that are ordinarily hidden in the procedure of wave analysis by applying more refined measurements. Then, the focus was brought on the following matters, a) the length of approach run of a model and the growth of ship waves, b) the effects of truncation for finite wave records, c) the effects of lateral position of longitndinal-cut, d) reflexibility of ship waves on the tank wall. It is hoped that the various results of these investigations will contribute not only to wave analysis problems but also to future development of wave resistance theory.