Parametric design and multi-objective optimisation of containerships

The introduction of new regulations by the International Maritime Organisation, the fluctuation of fuel price levels, along with the continuous endeavour of the shipping industry for economic growth and profits has led the shipbuilding industry to explore new and cost-efficient designs for various types of merchant ships. In this respect, proper use of modern computer-aided design/computer-aided engineering systems (CAD/CAE) extends the design space, while generating competitive designs in short lead time. The present paper deals with the parametric design and optimisation of containerships. The developed methodology, which is based on the CAESES/Friendship-Framework software system, is demonstrated by the conceptual design and multi-objective optimisation of a midsized, 6,500 TEU containership. The methodology includes a complete parametric model of the ship’s external and internal geometry and the development and coding of all models necessary for the determination of the design constraints and the design efficiency indicators, which are used for the evaluation of parametrically generated designs. Such indicators defining the objective functions of a multi-objective optimisation problem are herein the energy efficiency design index, the required freight rate, the ship’s zero ballast container box capacity and the ratio of the above to below deck number of containers. The set-up multi-objective optimisation problem is solved by use of the genetic algorithms.