Inspection of Submerged Structures

Antonio Vasilijevic, Nadir Kapetanović, Nikola Mišković

Abstract

Very common motivation for the inspection of underwater infrastructures is to measure and estimate their degradation status. Measurements required for this estimation could vary for different inspections but often include the size of the gap between the underwater structure and the seabed, between two structures or openings or cracks on the structure itself. Marine environment is very challenging for accurate spatial measurements because it is GPS-denied environment due to very high attenuation of the radio waves and because of very limited penetration of visual and laser signals, methods that are commonly used in terrestrial applications. Alternatives generally applied underwater are acoustic instruments for range measurement. The most appropriate instrument for multiple simultaneous range measurement is multibeam profiling sonar. In this paper, we describe the use case related to the inspection and monitoring of the degradation status of the steel hull of the ship that sunk one hundred years ago. The profiling multi-beam sonar attached to an Autonomous Surface Vehicle was used to inspect the degradation status i.e. to measure the gap along the ship side. These sea trials have showed that reliable estimation of submerged gaps/cracks and openings could be obtained utilizing this methodology.

Keywords

inspection; submerged structures; multibeam sonar

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IMEKO-TC10-2020-031.pdf

DOI

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IMEKO TC

TC10 - Measurement for Diagnostics, Optimization and Control

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