Autonomous Systems in the Underwater Domain: A Limitless Revolution?

Drones are not a novelty in the naval domain. The US Navy’s first attempts to use aerial kamikaze drones came during the First World War, when the German armed forces also used remotely operated kamikaze boats against British ships. The US Navy started developing fully operational underwater drones in the 1950s. In recent decades, numerous Western navies have deployed remotely operated underwater vehicles on mine warfare operations, primarily to reduce the risk posed to clearance divers. Ukraine’s Magura surface drones,2 among others, are the worthy modern heirs to over a century of naval engagement with unmanned vehicles.

The underwater domain has historically been a driver of innovation in the field of unmanned vehicles because of the difficulty for human beings to operate underwater at great depth or for prolonged periods. Underwater gliders, the first autonomous underwater vehicles, appeared in the 1990s, and the quest for ever greater autonomization in the underwater domain has continued ever since. But this search has always been constrained by the limitations of the underwater environment: opacity, non-homogeneity, water pressure, and salinity.

Spurred by the wave of enthusiasm around the possibilities opened up by the advent of aerial drones, a prolific and diverse range of naval drones has emerged, particularly underwater drones. This trend is largely being driven by industrial actors, who foresee a potential new revolution comparable to that of the aerial drone industry and have no intention of missing out on market opportunities, even if they have to fund a large part of the development costs themselves. 

This proliferation of new drones relies on the increasing commercial availability of standardized dual-use components, which have become significantly cheaper: electric motors and batteries, optic and acoustic sensors, and on-board electronics more generally. It also capitalizes on the industry’s decades of experience in the development of torpedoes and underwater robots and drones, as well as several advances in the relevant technology sectors. In this regard, these new products are as much original developments as they are aggregates of external standardized components. 

How should navies position themselves with regard to this flourishing and increasingly diverse technological offering? Given recent technological developments that herald greater autonomy in the future, how can they make sure not to miss out on the “drone revolution” in the underwater domain? 

The answer to this question requires both an intimate understanding of the constraints of the underwater environment and a realistic picture of autonomy in this domain. These are addressed in the first section of this report. 

Next, it calls for an interrogation of the contexts in which autonomous underwater vehicles are used during military operations, and the choices that these entail. The second section focuses on these considerations. 

Finally, these choices require every navy to define an operational concept that is suited to its autonomous underwater capabilities and to determine how best to integrate the latter into its force structure, which is where any potential revolution will take place. These questions are discussed in the final section.