When is a Ship a Ship? Use by State Armed Forces of Un-crewed Maritime Vehicles and the United Nations Convention on the Law of the Sea
[Law and the Future of War Research Paper No 3] Armed forces around the world are rapidly developing un-crewed maritime vehicles (UMVs) for use in military operations. Key to the strategic value of UMVs is that they will have no people on board, and instead be remotely controlled or, in the future, will be able to carry out some or all of their mission autonomously. But will they fit into the existing categories of the law of the sea set out in the in the United Nations Convention on the Law of the Sea (UNCLOS)? This paper considers whether two of the basic classifications of this body of law – being categorised as a ‘ship’ or ‘vessel’ and being a ‘warship’ – require people to be on board the vehicle and thus exclude UMVs. These categories are critical for the distribution of rights and obligations in the UNCLOS. Failing to qualify as a ship would significantly limit the strategic value of UMVs, restricting their navigational rights and possibly preventing states claiming sovereign immunity. Along with the important practical implications of these definitional challenges, they also serve as an example of when an evolutionary interpretation of international treaty law should be preferred. The paper shows that the better interpretation of ship in UNCLOS is capacious enough to include both remotely controlled and autonomous UMVs. However, the more restrictive definitional requirements of warship in UNCLOS will be more difficult for UMVs to meet.