Ship design is a complex study requiring the coordination of many disciplines and accurate calculations, as well as cost considerations. Thus, ship designers have to design the naval ships that successfully fulfill the desired performance in a cost-effective manner with respect to international and national rules and regulations. In this context, finding the optimum solution for the design has been an important challenge for ship designers. Design optimization is selecting the best solution among many viable solutions based on a criterion or multicriteria and inherently coupled with the design cycle. This study presents an application of the integer linear programming and multicriteria decision-making (MCDM) methods of Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) and Simple Weighted Sum Product (WISP). A design of the ship drainage system is considered as the case study for this purpose. Based on the usage and location of the ejectors and drainage pumps, four design alternatives and 12 scenarios for each alternative are proposed. The optimization problem is solved for each design alternative, and an optimal design solution among alternatives is evaluated by TOPSIS and Simple WISP methods. The similarity of the solutions from the two MCDM methods is measured by Cosine Similarity, which indicates a strong similarity.
Ship design is a complex, iterative, and sophisticated process affected by a number of factors. Among these factors, the issue of cost efficiency has come to the fore along with the project method and system integration during the last century. Therefore, ship designers have to design the most cost-effective ship for a specified purpose regarding national and international rules and regulations. Within this context, the cost considerations in the design calculations of the systems onboard are as important as their accuracy and adequacy. Thus, finding the optimum solution within the given limits is challenging for ship designers, engineers, and system integrators. For this purpose, design optimization tools have been implemented in ship design.