The core competence of any medium-to-large sized shipyard includes the panel assembly line. Ship panels are the basic building blocks of well over 60% of the interim products of typical commercial ships. Therefore the improvement of the panel assembly process could greatly reduce the number of man-hours of all assembled panels, thereby yielding significant savings to the shipyard. Using a lean methodology to make kaizen improvements to traditional panel assembly lines will greatly reduce the costs in ship production. This means that shipyards, which are barely keeping earnings above costs, will be able to increase profits. Value stream mapping is a key way of determining how lean a production process is. The wastes in production assembly are readily identified as well as the takt time and the areas where there is push as opposed to pull. In this paper, a case study of a typical commercial shipyard, which builds a product mix of vessels is analyzed. The present state panel assembly line is mapped and then using lean tools and avant-garde technologies, such as hybrid laser arc welding, the new transformed panel assembly line is demonstrated to bring man-hour reductions of over 80%, so that a typical panel is assembled using 12 man-hours as opposed to the present 72 man-hours.

The main shipbuilding assembly processes greatly influence the flow of interim products in a newbuilding shipyard. The panel assembly line is a major process located upstream of all the other shipyard assembly processes. In a previous paper, the application of lean principles enabled a balanced and smaller takt time along the workstations and yielded significant savings in man-hours. Although a panel consists of butt-welded steel plates with multiple fillet-welded longitudinal stiffeners, a built-up panel is this same panel fitted with longitudinal and transverse steel elements. Since there are many internal structural elements, the man-hours along a traditional built-up panel assembly line are multiple times greater than that of panel assembly. Therefore, it is necessary to analyze and map built-up panel assembly in an actual newbuilding shipyard. Using value stream mapping along with kaizen principles of continual improvement to determine the transformative steps to make the traditional built-up panel assembly line leaner. This enables significant man-hour reductions of about 60%, which yields remarkable cost savings to the shipyard.

The modern system of shipbuilding includes applying integrated hull construction, outfitting and painting (IHOP) of ship interim products, as opposed to the traditional manner of first constructing the hull blocks, then performing basic outfitting and finally painting, all separate of each other. Even though most shipyards apply some degree of integration of all trades during vessel construction, much work could still be better integrated. This paper analyzes and maps the present IHOP construction of a typical shipbuilding erection block in a real shipyard. Through the application of a Product Work Breakdown Structure (PWBS) and group technology, the degree of IHOP integration could be increased. This is demonstrated to be in compliance with the lean principles of improving flow and kaizen. The paper will suggest how the vessel construction could be become leaner through a value stream map, thereby decreasing both duration time and man-hours thus securing significant savings for the shipyard.

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