Generally, understanding shape deformation and the precise amount of three dimensional deformation at manufacturing processes is important in accuracy control. Since ships are very large products, three dimensional deformation measurements are very difficult to conduct during ship manufacturing process, and for that reason only few cases have been reported. In this study, a hatch cover is selected as a target structure and the three dimensional welding deformations observed in each manufacturing process.

This study examined the measurement accuracy of the total station in the actual shipyard and impact factor to the measurement accuracy are examined. Moreover, we conducted tracking investigations on the deformation of the hatch cover due to the progress of the process, and the accuracy improvement methods are examined.