Typical application of bidirectional DC/DC power converter exists in hybrid cars. Recently, a similar approach has been applied in hybrid propelled ships as well. In this paper, a novel low power bidirectional DC/DC power converter of standard Buck/Boost topology has ben designed in order to explore possibilities of the high power design in maritime applications. In order to discover critical points of a design, thermal imaging has been investigated. The results clearly indicate that the proposed solution is more cost effective than a typical standard bidirectional DC/DC power converter. Likewise, the improvement in maneuvering of the propelled vessel system with two and more electric drives has been investigated and compared to a classical diesel, single engine propulsion system.

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Value stream mapping is used to analyze and improve the production flow in many industries, which includes the airplane and automobile industries worldwide. The shipbuilding industry has adopted lean manufacturing techniques. However, the amount of value stream mapping application in the shipbuidling industry is still relatively sparse due to the large variety of interim products and ship types. The aim of this paper is to analyze the interim products of a typical sized commercial shipyard with a product mix of chemical tankers and asphalt barges to demonstrate how a lean transformation can be performed using a shipyard value stream mapping methodology. The case study maps the typcial panel assembly lines of the shipyard and demonstrates the differences between the ship type interim products and using the lean manufacturing methodology developed by the authors to demonstrate how to define and adjust the production facilities using both lean and group technology techniques to create an improved production line which is demonstrated through a future improved value stream map. The main criteria for analyzing and comparing production improvement is through man-hours and duration time. The future value stream map has improvements of up to 50 percent, which demonstrates the importance of adopting a value stream mapping methodology for shipyards aiming to improve world competivity by decreasing production costs, while maintaining and/or improving quality of the ship buidling blocks.

DFP analiza izrade robotiziranih međuproizvoda u brodogradnji SažetakBrodograđevna industrija spada u jedne od najkompleksnijih proizvodnih industrija. Dugi niz godina se nastoji postići optimalna proizvodnja, sa minimalnim gubicima i maksimalnim rezultatima konačnog proizvoda-broda. Da bi se omogućio takav pristup proizvodnji potrebno je redovito modernizirati proizvodne procese u brodogradilištu tj. biti u toku sa svjetskim trendovima u proizvodnji broda. Ulaganje u unapređenje proizvodnih linija je ključan i primaran potez za postizanje ušteda. U svijetu industrije je zavladao trend težnje za automatizacijom i robotizacijom proizvodnih pogona iz razloga jer još uvijek nije postignut željeni i zadovoljavaći stupanj automatizacije/robotizacije. Iz tog razloga većina brodogradilišta je u stadiju djelomično automatiziranih i robotiziranih pogona radi čega je još uvijek vrlo veliki postotak prisutnosti ljudske radne snage. U ovom članku će se osvrnuti na nedostatke proizvodnog procesa promatranog brodgradilišta sa ciljem davanja uvida u mogućnost optimiziranja predmontažne faze gradnje broda. AbstractThe 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.