Lamp Ray: ship hull assessment for value, safety and readiness

Lamp Ray, an ROV based underhull inspection system, is a method for in-situ, underwater surveys of the hull condition. Comprising a hull-crawling inspection vehicle, which is integrated with a very precise hull tracking capability and data management system, the Lamp Ray processes quantifiable data on hull plate thickness, coating condition, galvanic potential field and hull form. Because the location of the Lamp Ray inspection sensors on the hull is always known with great accuracy, all survey data can be correlated to an exact plate position, yielding permanent and repeatable information which can be used for planning hull repairs and for long term trend analysis of hull condition. The paper describes the Lamp Ray inspection system and process, taking the reader through system calibration, deployment, hull form mapping and hull condition survey. The data products resulting from the Lamp Ray survey process are described and examples of the report are given. These reports include color visualizations of plate thickness gauging, plate diminution, coating thickness and cathodic potential field. A case study is also included of one Lamp Ray survey, which illustrates the significance of the technique. The Lamp Ray process should be of great interest to ship owners, ship managers, regulatory agencies, underwriters and inspection personnel who are interested in tools for condition-based maintenance and planning which provide cost effective alternatives to drydock and diver deployed survey methods