Abstract : This report discusses research conducted to investigate and develop hydrographic survey equipment for objective, detailed, and quantitative definition of the underwater shape of coastal structures. The research included development of and investigation of the Coastal Structure Acoustic Raster Scanner (CSARS) system. Although much information was gained from CSARS development, the capabilities of commercially available multibeam systems like the SeaBat 9001 multibeam sonar system surpassed the still prototype CSARS. Therefore, this investigation concentrated on multibeam sonar systems, and field demonstrations and trials were conducted with the SeaBat system. The SeaBat system was successful in providing accurate, high resolution hydrographic data on the underwater condition of various structures. With multibeam sonar systems, it is now possible to have types of survey information that were previously impractical to obtain or were unattainable, leading to safer, more cost effective management of coastal structures over their lifetimes.