The main objective of this paper for weight and cost consideration designs is to give the designer a better tool to compare the relative merits of various design alternatives and to be able to select the corresponding most minimum weight or cost-effective design. An example of a typical problem in shipbuilding is studied in order to explore some general aspects of -design. Two different structural forms are considered (flat and pitched). In order to obtain realistic comparisons, the production costs considered in this research are according to the current practice in Egyptian shipyards. A key finding from the results is that if the optimisation is based on a minimum weight or minimum cost criterion, the pitched structures are superior over the flat ones. In other words, significant savings in weight and cost can be achieved by replacing flat structures by pitched structures. The labour cost should include the pre-fabrication, sub-assembly, fitting and other relevant activities costs in addition to the welding costs. In addition to the material and labour costs, the total costs should include the overhead costs in order to make a realistic decision for best design.