This paper examines technologies around power and propulsion (P&P) systems including design requirements, training, maintenance, and operations exploring how recent advances in these systems can help facilitate a lean crewed warship. The paper draws on the authors experience in the cruise industry and how crewing challenges have been addressed commercially with existing and emerging technologies. The paper challenges the current techniques of P&P analysis and proposes alternative processes for analysing conflicting requirements such as equipment acquisition costs, lean crew objectives, redundancy, and systems efficiencies. Associated risks, opportunities and regulatory framework of a lean crew are investigated. The role of automation, remote condition monitoring and virtual reality is explored. Some recommendations are made for how these technologies can be adopted while still maintaining safety, resilience, and capability.