In the immediate aftermath of the Great Hanshin-Awaji Earthquake in 1995, there was a rush to carry out surveys of water routes in the Port of Kobe to deliver relief supplies. The hydrographic survey instrument that played an important role in these surveys was the first multibeam echo-sounder in domestic firms and had literally just been introduced. Twenty years have passed since then and the multibeam echo-sounder has now become an indispensable instrument not only for surveying the sea floor but for the inspection of wharfs and marine structures, and measurement of dams and rivers.