A Packing Approach for the Early Stage Design of Service Vessels

Naval architects often say that every ship is a compromise between many conflicting requirements. This widely-held belief immediately raises the question as to what kind of ship and, therefore, what kind of compromise, would suit the ship owner’s interest best. The approach presented in this thesis aims to improve the early stage design process of service vessels by helping the naval architect to generate and explore a large and diverse set of three-dimensional ship designs. In turn, this set enables the thorough investigation of a wide range of different compromises before settling upon a well-founded –and a more competitive- ship design that reflects the most promising compromise and, as such, will be deemed desirable by its owner. The approach has four key features. Firstly, it uses a novel parametric ship description (based on `packing problems’) that can handle large and concurrent changes to the entire three-dimensional ship design, i.e., hull, superstructure, decks, bulkheads and the arrangement of systems in the ship can all change without human interaction. Secondly, it uses a search algorithm to generate a large and diverse set of ship designs that reflect a wide range of different compromises. Thirdly, the naval architect considers all feasible designs to gain insight in conflicting characteristics before selecting the most promising ship designs in a transparent manner. The selection can be based on objective and constraint values, as well as on the naval architect’s own engineering judgement. Fourthly, the naval architect takes all selection decisions to help instil the crucial sense of ownership for the ship designs that result from the selection process. This novel design approach has been applied successfully to design two types of service vessels: deep water drillships and frigates. It proved able to establish the design impact of variations in payload and performance requirements. Moreover, the resulting set of designs was subsequently used to illustrate how the naval architect can identify and select designs that excel at particular performances, such as sea-keeping. In summary, the approach is expected to improve the naval architect’s ability to identify promising ship designs early on, which should lead to the design of more competitive service vessels.