Background paper on the legal framework for the use of unmanned maritime systems in naval operations

Unmanned maritime systems (UMS) designed to carry out functions on or below the surface of the ocean without a captain and crew physically on board, have become part of the inventory of many states and they are expected to play an increasingly important role in the fleet architecture and operations of future high-tech navies. This is not least the case for states (like Denmark) who are responsible for the maintenance of maritime security and protection of national and economic interests in vast areas under their coastal state jurisdiction. Lifting this responsibility is both cost-heavy and time consuming and entails tasks that exceed the capacity of many traditional navies – making the versatility and capabilities of UMS particularly interesting for such states.

Notwithstanding the potential military benefits of UMS, the legal framework for their use, particularly the question of UMS’ legal status under UNCLOS and the law of armed conflict at sea is, however, unsettled. The lack of agreement about whether UMS can constitute ships and warships has, among other things, created uncertainty about the extent to which UMS enjoy key rights granted to ships and warships under UNCLOS and customary international law, including navigational rights, immunity, and belligerent rights.

This background paper seeks to cast light on the current development of the legal framework for military use of UMS and to discuss the implications of remaining legal uncertainties for the use of UMS in Danish naval operations.