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Material Matters
Novel coating assessment for ships evaluates corrosion while saving time and reducing costs
A ship such as the 684-ft (208.5-m) long USS
(LPD-17), an amphibi-
ous transport dock ship, would require approximately eight overview images for its portside image set. U.S. Navy photo by Mass Communication Specialist 3rd Class John K. Hamilton.
Laboratory (NRL) (Washing- ton, DC) has developed a novel process to inspect the condition of exterior ship- board coatings on U.S. Navy ships that is faster, less labor intensive, and more econom-
A 14 MATERIALS PERFORMANCE March 2012
ical than current methods. Traditionally, topside coatings assess- ments are conducted using visual evalu- ations combined with physical measure- ments of coating adhesion, thickness, color, and gloss performed by NACE 1V\MZVI\QWVIT KMZ\QÅML +WI\QVO 1V[XMK-
team of researchers with the Center for Corrosion Science and Engineering at the Naval Research
tors and NACE Shipboard Corrosion Assessment Training (S-CAT)-trained engineers and technicians. The entire assessment process can take up to three months of personnel hours to complete, depending on the size of the ship. "Cur- rent methods of performing inspections of ship surfaces are slow, labor-intensive, and highly subjective. These inspections require significant time-consuming manual processes to measure dry coating thickness, color fade, as well as the visual inspection for corrosion damage and blistering below the surface of coating materials," says John Wegand, one of the NRL researchers with the Center for Corrosion Science and Engineering. The new coatings assessment process
uses a computer software program de- signed by the NRL team that performs an automated analysis of high-resolution photographs of a ship taken with com- mercially available digital cameras. When compared to the in-depth coatings assess- ment method, the researchers report at least a six-fold reduction in the effort re- quired to perform a coatings assessment using the computer program and photo- graphic images, as well as a reduction in logistical support. While the streamlined image-based coatings assessment is not intended to replace the in-depth visual/ mechanical (manual) coatings inspection performed by trained coating inspectors, it could be used as an additional assess- ment tool in combination with the manual coatings inspections to more economically track a ship's coatings per- formance over time.
NACE International, Vol. 51, No. 3
San Antonio