It is the PMM test to investigate the nature of the fluid force acting at the time of maneuvering motion by giving motion to a model of a ship or underwater vehicle forcibly. Using the mathematical model that expresses the fluid force obtained in this test, simulation calculation of the maneuvering motion becomes possible on a computer. We design and manufacture P.M.M. testing machines tailored to each experimental water tank. We also respond to requests for gage gauges, measurement systems and analysis programs.