As a long-term sustainability approach to shipping, the European FP7 project MUNIN (Maritime Navigation through Intelligence in Networks) develops a concept for an unmanned and autonomous merchant vessels and investigates the feasibility to operate a dry bulk carrier completely unmanned during deep sea voyage. A core objective is to create a system, which allows autonomous ship navigation at least on the same safety level or comparable to conventional vessels, but preferably even higher. Due to an expected simultaneous operation of manned and unmanned vessels on the oceans, it must be considered that the autonomous system still has to fit into the existing international legal framework of shipping.