This paper introduces the ShipSIM, a novel free (standard conforming) Modelica library for modeling and simulation of ship maneuverability. This first Modelica library in the field of ship propulsion and maneuverability provides the components and flexibility to model the ship propulsion, hydrostatics and hydrodynamics to develop ship maneuvering simulations fully compatible with the Modelica Standard Library components. In this paper is presented the library’s key features and structure and introduce the underlying physical and mathematical foundations and modeling approaches. In addition, current implementation status, applicability limits and future development is discussed. The library development is coordinated by the authors and it is used in several MSc thesis. ShipSIM library is available on http://modelica-spain.org:3000/ Basilio/ShipSIM.