  Here, we present the concept of an open virtual prototyping framework for
maritime systems and operations that enables its users to develop re-usable
component or subsystem models, and combine them in full-system simulations for
prototyping, verification, training, and performance studies. This framework
consists of a set of guidelines for model coupling, high-level and low-level
coupling interfaces to guarantee interoperability, a full-system simulation
software, and example models and demonstrators. We discuss the requirements for
such a framework, address the challenges and the possibilities in fulfilling
them, and aim to give a list of best practices for modular and efficient
virtual prototyping and full-system simulation. The context of our work is
within maritime systems and operations, but the issues and solutions we present
here are general enough to be of interest to a much broader audience, both
industrial and scientific.
