The development of concept designs during early warship design stages is essential to inform stakeholder dialogues on technical feasibility, affordability, and risk. One of the key aspects of warship concept designs is the layout of systems in the overall arrangement. The adoption of real-time design processes, such as concurrent design, require naval architects to use layout design tools in a more dynamic setting than during traditional design review session-based design processes. This paper investigates how ship layout design tools can be used in a real-time manner. It does so by considering the arrangement problem of allocating systems to compartments, subject to available and required area, global system position preferences, and preferred relative system positions. An existing ship layout design tool, WARGEAR, is extended to consider global and relative system constraints, and is integrated in a proposed method for the allocation of systems to compartments. Furthermore, a novel two-item correlation metric is developed to support designers in the analysis of the, typically large, design space. The metric can be used to identify conflicts and trade-offs between design parameters, as well as promising combinations of design parameters. Two case studies (8 and 89 systems respectively) are used to demonstrate and evaluate the proposed method. Based on these case studies, the calculation time or accuracy of the allocation method does not seem to be the main issue for collaborative design decision-making. Indeed, most effort is required for the analysis of the generated concept designs. Since this is not a problem as such, the real-time use of automated design tools to evaluate the impact of proposed design changes seems to be a promising way to enhance the effectiveness of collaborative ship layout design sessions.