Measuring the Monitor: 3D Imaging of the Civil War Ironclad’s XI-Inch Gun

Abstract

Mickey Hardin, SURVICE Metrology; William Mongon, Accurex Measurement Inc.; Marcie Renner, The Mariners’ Museum; and David Krop, The Mariners’ Museum; his article describes an inspection project that highlights the areas where today’s three-dimensional (3-D) imaging technologies provide a great range of capabilities for inspection and reverse-engineering requirements. The project involved measuring and analyzing the starboard gun from the Civil War ironclad USS Monitor. A 3-D computer-assisted design (CAD) model was generated using historic records and then compared to the scan measurements using laser and structuredlight technologies. The data can be used as a conservation tool for future monitoring activities, as well as a resource to provide historians with insights into quantifying the manufacturing capabilities of the 19th century. In addition, despite the antiquity of this measured asset, the scope of this project is typical for today’s marketplace, and the effort is well-suited to demonstrating costreduction techniques for similar inspection planning, selective data processing, and conclusive data analysis.