Capability-Based Approach for Naval Ships Design: A Metric Formulation

European shipyards are expert at designing technological advanced and high value systems, such as naval ships. The increasing complexity and quality of the performances required by this kind of vessels demands for a novel approach to the Warship design. The traditional design method, represented by the well know “design spiral”, works well when the design architecture has been already selected, but it is necessary to define a method to previously explore the problem domain. This is very useful also during the final delivery phase because the identified design requirements are going to be used to provide evidence about their fulfillment in relation with the selected design solution. A Warship is a complex system where the Platform and the Combat Systems are tightly interconnected to achieve stakeholders required missions, which are the core of a naval ship. Assess the missions effectiveness and technical performances is crucial both at the very beginning while analyzing trade-offs of different solutions and in the final phase during Verification and Validation of the selected one. This is possible by integrating the traditional naval ship design with the System Engineering (SE) methodology. SE is a powerful approach to develop complex systems and its process is well represented by the V-model, which follows the design  from the Concept Phase up until the Production Phase. The Verification and Validation Processes, which take place at increasing level of the V-model, are essential to assess the effectiveness of the project and to control its development. In these perspective, it is necessary to define Measures of Performance (MOPs) and Measures of Effectiveness (MOEs). MOEs are closely related to the achievement of the mission in the intended operational environment, while MOPs characterize physical attributes related to the system (ship) or subsystems and they are measured under specific operational conditions. Identification of  MOEs and MOPs implies the definition of what a Warship is supposed to do and in what extent. A Capability Based approach can well identify the naval vessel emergent properties by reducing the complexity of the whole system (ship) through a breaking down of the problem. In this this paper  the V-model integration into the naval ship design process will be discussed with a specific focus on MOEs and MOPs identification. Making reference to a comprehensive description of a Warship Capabilities available in literature, a rational approach will be developed to identify the most appropriate metrics for the design assessment, i.e. Verification and Validation of the ship effectiveness in  an operational environment. Some Capabilities will be selected (for example among a subset given by buoyancy, stability, structural strength, power generation, controllability, safety) and analyzed to identify fundamental measures such as the Key Performance Parameters (KPPs) for MOEs and the Technical Performance Measures (TPMs) for MOPs. Such process will enable the integration of the ship design spiral with the Systems Engineering V-model.