Automated hull inspection for the identification of mines or foreign bodies on a moving vessel

u s and IMO legislation is evolving to dictate that vessels must be surveyed for the identification of mines or contraband prior to entering port. However, present techniques are limited by the fact that the vessel must be halted offshore for the survey to be undertaken. This thesis proposes an alternative method based on seabed mounted transducers that face the sea surface allowing vessels to be surveyed while in motion. The study was aimed at investigating the potential for such a system and identifying any issues that may arise. The proposal was tested through a series of practical studies, where a 154m long, 6m drafted passenger ferry was surveyed in Millbay docks, Plymouth using a pole mounted 468 kHz SEA SwathPlus interferometric sonar. The ferry was effectively surveyed while in motion and static providing four datasets with good hull coverage and resolution. Further trials were undertaken surveying smaller vessels from the dockside at Sutton Harbour, Plymouth, although bad acoustic conditions prevented the acquisition of quality data. A number of issues arose throughout the investigation, including multipathing, range ambiguities, aeration of the water and noise. Although the findings show that many issues could be resolved through careful system design, the main limitations being the location and frequency of transducers. Recommendations were made as to the most appropriate set-up and further work that may help in designing the final system.Faculty of Scienc