Liner shipping has recently experienced a surprising expansion in the size of the largest container ship. This tendency towards breaching the previously existing size barrier is explained by the potential economies of scale that can be reaped from utilising such ships. Model outputs provide an insight into optimal container ship size. Suggestions are made concerning the optimal deployment of the current fleet of such vessels, likely future trends in container ship size and deployment ,and the impact this will undoubtedly have upon container operations, logistical systems, and ports.