Submerged naval hull fast monitoring and inspection by means of remotely operated underwater vehicles

This paper illustrates a novel approach for structural inspection and visual monitoring of ship hulls based on low-cost mini- Remotely Operated Underwater Vehicle (hereinafter referred to as ROV). ROVs are vehicles suitable for underwater navigation. Depending on its size, a ROV may be used to perform either complex operations (i.e. work-class ROV) or underwater inspections (i.e. inspection class ROV or mini-ROV class). Nowadays, the current level of technological miniaturization of the sensors and the instruments allows to overcome many of the operational problems due to the limited load capacity of the ROVs. This paper aims to propose the system architecture and algorithms to perform reliable and low-cost surveys by underwater mini-ROVs. This aspect is crucial for keeping ship operational efficiency and optimize maintenance frequency by limiting the operational costs. Indeed, limiting hull corrosion and biofouling plays a main role in the traction power and environment emission saving. A mini-ROV equipped with appropriate technologies for the structural checking and biofouling identification has been defined and constructed. Preliminary theoretical and experimental tests on the system architecture have been carried out to verify its reliability. First analyses are carried out and the results are encouraging and make it viable to perform an in-depth experimental campaign in the field aimed to test both the system and its reliability in performing fast and low-cost ship hull surveys.