This paper examines the shape of future naval fleets and how they could contain radical new warship platform concepts including multi-hulls with hydrofoils able to sprint at high speed to respond to an emerging crisis. The lean, mean and green radical concept discussed is a Small Waterplane Area Nonohull (SWAN) with nine connected hulls. Propulsion arrangements are enabled by the electric ship concept, arranged for survivability in the modular multi-hull arrangement. The paper addresses the drivers for moving from evolution to revolution in warship design and how, when faced with radical new concepts, we can test, and accept them using modelling and simulation.