Nikša Fafandjel

Shipyard production cost structure optimisation model related to product type

Establishing a shipbuilding production cost structure is a fundamental management activity, concerning materials and fabrication. Shipyards compete in world market niches regarding vessel type and dimensions. Therefore, the vessels market price has a tremendous influence on the shipyards determination of the price of the vessel offered to buyers. For this reason, shipyard management is forced to concentrate its efforts on production cost structure optimisation in order to achieve the goal of a profitable shipyard. In this paper, a computer-integrated cost structure optimisation model for defining an optimal and profitable vessel production cost structure is presented. Statistical analysis of the data was performed for a sample of tankers, built in selected shipyards. Probabilistic theory was applied and several results, such as expectation for aggregate figures, are presented. Such a tool for obtaining an optimal production cost structure enables shipyard management to carry out more effective decision-making, and also better cost control within model parameters. Furthermore, dynamical control of costing figures for the whole shipbuilding process is possible and has a significant influence on the final results. The mathematical model for achieving an optimal structure of the production costs was verified and tested against a real example of the construction of tankers.

Lean Methodology to Transform Shipbuilding Panel Assembly

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.

Lean Built-up Panel Assembly in a Newbuilding Shipyard

The main shipbuilding assembly processes greatly influence the flow of interim products in a newbuilding shipyard. The panel assembly line is a major process locatedupstreamofalltheothershipyardassemblyprocesses.Inapreviouspaper, theapplicationofleanprinciplesenabledabalancedandsmallertakttimealongthe 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 alongatraditionalbuilt-uppanelassemblylinearemultipletimesgreaterthanthatof 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 kaizenprinciplesofcontinualimprovementtodeterminethetransformativestepsto 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.

DFP analiza izrade robotiziranih međuproizvoda u brodogradnji

The shipbuilding industry belongs to one of the most complex manufacturing industries in the world. During the last couple of decades efforts were made to achieve optimal production, with minimal waste and maximum results of the final product – a ship. In order to allow for this type of manufacturing approach it is necessary to modernize the production processes of a shipyard on a regular basis by following world trends in shipbuilding. Investments in the advancements of assembly lines is a key and primary move towards achieving savings. In the industrial world there is a constant goal of automation and robotization of assembly processes since the degree of achieving this goal is still not satisfactory. Based on this reason the facilities of most shipyards are still only partially automated and roboticized, which means that there is still a large percentage of manual work. This paper analyzes the fallbacks of the assembly processes of a specific shipyard with the aim of providing insight into the realistic possibilities of optimizing the assembly phase of shipbuilding.

New Building Production CostsStructure Optimisation

Establishing newbuilding production costs structure represents a fundamental management activity, concerning materials and fabrication in shipbuilding. Shipyards are competing in world market niches, regarding vessel types and dimensions. Therefore, vessels market price has a tremendous influence at shipyards determination of vessel price offered to buyers. For this reason shipyard management is forced to concentrate its effort to act upon newbuilding production costs structure optimisation as to achieve the goal of profitable shipyard enterprise. In this paper, a computer integrated mathematical model of costing engineering of vessel production founded by authors is presented. Model concept is based on both, functional and technological, vessel breakdown structures. Statistical analysis of data was performed for a sample of tankers population, built in Croatian shipyards. Probabilistic theory was applied and several results such as of expectation for aggregate figures are presented. Such developed tool for obtaining an optimal production costs structure enables shipyard management besides more successful managing and decision making, also latter through the process a better costs control within model parameters. Dynamical control is needed of costing figures within optimised structure of production costs, that for assigned conditions, for the whole shipbuilding process and product, have significant influence upon performance final results. Mathematical model for achieving optimal structure of production costs was verified and tested against real example for tanker newbuilding. Transactions on the Built Environment vol 42,