Automation of the finishing process of steel yacht hulls based on optical scanning

Purpose: The manufacturing of large yacht hulls is a complex process in the shipbuilding industry. The traditional approach is based on the pre-fabrication of large steel panels that are welded together to form 3D superstructure assemblies. One of the most relevant aspects of a yacht is its visual impact. For this reason, a finishing phase is usually carried out in order to obtain a final target surface with smooth curvature. Current methodologies mainly rely on manual processes thus requiring a great amount of time and well-experienced workers. Method: This paper introduces an innovative methodology representing the basis for the automation of the finishing phase of large yacht hulls. The proposed approach is based on the measurement of the as-built hull surface through the integration of an active stereo vision system and a complex mechanical tracking system. A procedure to define the target surface has been developed by integrating information deriving from both the design and the as-built shapes. Result: The developed methodology has been tested on a broadside region of the hull of a 59 metres yacht assembled within a shipyard. A target surface, differing as little as possible from the design surface, has been modelled in order to obtain a uniform curvature shape. A finishing phase has then been carried out by applying a layer of filler and by milling the hull’s surface. Discussion & Conclusion: Results obtained have demonstrated the feasibility of the proposed approach, speeding up the whole process and guaranteeing fair reflection line patterns on the manufactured surface.