Even though the early-stage design of a complex vessel is where the important decisions are made, the synthesis of the distributed ship service systems (DS3) often relies on “past practice” and simple vessel displacement based weight algorithms. Such an approach inhibits the ability of the concept designer to consider the impact of different DS3 options. It also reduces the ability to undertake Requirements Elucidation, especially regarding the DS3. Given the vital role the many DS3 provide to a submarine, this research considers whether there is a better way to synthesise DS3 without resorting to the detailed design of the distributed systems, which is usually inappropriate at the exploratory stages of design. The research proposes a new approach, termed the Network Block Approach (NBA), combining the advantages of the 3D physical based synthesis UCL Design Building Block (DBB) approach with the Virgina Tech Architectural Flow Optimisation (AFO) method, when applied to submarine DS3 design. Utilising a set of novel frameworks and the Paramarine CASD tool, the proposed approach also enabled the development of the submarine concept design at different levels of granularities, ranging from modelling individual spaces to various DS3 components and routings. The proposed approach also allowed the designer to balance the energy demands of various distributed systems, performing a steady-state flow simulation, and visualising the complexity of the submarine DS3 in a 3D multiplex network configuration. Such 3D based physical and network syntheses provide potential benefits in early-stage submarine DS3 design. The overall aim of proposing and demonstrating a novel integrated DS3 synthesis approach applicable to concept naval submarine design was achieved, although several issues and limitations emerged during both the development and the implementation of the approach. Through identification of the research limitations, areas for future work aimed at improving the proposal have been outlined.