Classification societies (Lloyds Register of Shipping, the American Bureau of Shipping, RINA, Germanischer Lloyd, Bureau Veritas, Det Norske Veritas, Russian Register, Polski Rejestr Statkow) require inspection of the state of the outer steel hull of a ship no less than twice every five years, and the time between any two inspections should be no longer than three years. It is necessary to meet these demands to obtain a certificate for operating a ship. Before inspection of the state of a ship hull, it is necessary to clean its underwater surface from marine fouling. Presently, these operations are performed manually in a dry dock; the cleaning time is about 24 h. After the cleaning is completed, an inspector visually checks the state of the hull and measures the hull thickness in different places (chosen by the inspector) with an ultrasonic probe. All this leads to substantial financial outlays due to the expense of work in the dry dock and high cost of out-of-service time (waiting for inspection, the ship entrance into and launch from the dry dock). As a result, the owners of ships try to clean the body surface and inspect the state of the hull as seldom as possible. The possibility of nondestructive testing of a ship hull with the AURORA underwater robot is discussed. The robot performs underwater cleaning of a ship hull with simultaneous contactless measuring of the thickness of the hull sheet with an ultrasonic detector; it tests the state of the protective coating and restores the shape of the underwater part of the hull.
Nondestructive testing of the state of a ship's hull with an underwater robot
Zerstörungfreie Prüfung des Zustandes eines Schiffsrumpfes mit einem Unterwasser-Roboter
Russian Journal of Nondestructive Testing ; 44 , 9 ; 626-633
2008
8 Seiten, 9 Bilder, 8 Quellen
Aufsatz (Zeitschrift)
Englisch
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