An electrical/propulsion integrator is essential for electric and hybrid vessel design, merging ship and shore electrical systems with vessel propulsion to improve performance and reliability. They coordinate batteries, power distribution, and propulsion, working with designers and shipyards to optimize efficiency and manoeuvrability, ensuring best performance. Early involvement of integrators brings both benefits and challenges, impacting owner requirements and design/build concepts at shipyards. The process will yield vessels that meet or exceed specifications with single vendor lifecycle support. Wartsila’s experience with WETA ferries and Buquebus ferries system design, integration and supply integration and supply gives Wartsila a unique perspective.