Abstract
In the present situation, inspections by eye are widely used to diagnose fishing port facilities. However, regarding submersible parts of breakwaters and mooring facilities, it is pointed out that the results of visual checks by divers are inconstant and subjective. Also, submersible surveys are required to be improved from perspectives of taking considerable time and efforts as well as considering safety concerns. In this research, an inspection method using narrow multi-beam sonar was examined to assure objectivity of submerged facility inspections and alleviate diving works. Its applicability was examined by on-site tests based on the judgement standard of deterioration for fishing port facilities. As a result, high applicability of this method was confirmed to evaluate relatively large-scale and detrimental damages such as transfer, scattering and damages of wave dissipating blocks, deficits of concrete structures, and lack of electric protections. Its effectiveness as a screening of submersible surveys was confirmed through using this method as a simple diagnosis prior to detailed inspections.
