This research investigates the application of A3 Architecture Overviews (A3AOs) in subsea front-end engineering studies. A3AO is a valuable method to support multi-disciplinary communication and share architectural knowledge in complex engineering domains. The method captures key information of an overall system and displays the system overview in a standard A3 format. In this paper, we investigate the beneficial impact a global subsea supplier can gain by applying A3AO as part of their concept evaluation process in the early phase study. Through interviews and a survey, we identified company's main challenges in concept evaluation of tie-in and connection system. We then applied the A3AO method to investigate its mitigating effect in early phase concept evaluation. We found that the company resources found the A3AO to provide a holistic system overview and support knowledge sharing. Overall, our research supports the use of A3AO as a method to promote common understanding.