: E-Navigation aims to enhance the safety and security of maritime activities by exchanging, integrating and analyzing the data between and in ship-side and shoreside systems. In this paper, we present the main characteristics of our semantic data exchange concept developed in the COSINUS project. In addition to the main task of exchanging data written in a variety of formats between on-board and onshore systems, each semantic data processor, which is related to a maritime system like ECDIS (Electronic Chart Display and Information System) or VTS (Vessel Traffic Service), defines a context model, which itself concludes information from the transient streams of data, registers the current state and the history of the ships, assigns some important meta-data such as data quality information and applies semantic compression by sending the interesting patterns only. Therefore, the context models in our data exchange represent cooperatively the navigation situation and this enables coopera...