SEARENITY, the magnetic hull-cleaning robot designed to decarbonise maritime transport

Accounting for nearly 3 per cent of greenhouse gas emissions, the maritime sector is equivalent to the world’s sixth-largest emitter. In 2023, the International Maritime Organisation set a target of carbon neutrality by 2050 for global maritime transport and a reduction of at least 40 per cent by 2030. To achieve these targets, France has drawn up a roadmap and a comprehensive action plan.

Reducing the hydrodynamic drag of ships (resistance to forward motion) is one of the possible measures. This leads to improved energy efficiency, thereby reducing ships’ fuel consumption and associated emissions.

With SEARENITY, the project partners propose to address this issue, not through changes to ship design, but by tackling biofouling, also known as biological fouling. Naturally, within a few hours, micro-organisms settle on the hull of ships and form a thin, oily layer known as a ‘conditioning film’. This biofilm thickens day by day and gradually becomes home to larger organisms such as mussels, clams and barnacles… leading to up to a 25 per cent increase in fuel consumption.

The SEARENITY project aims to develop an autonomous underwater drone that attaches to the ship’s hull via magnetic attraction. It is designed to operate continuously whilst the ship is underway to remove the biofilm and thus maintain the ship’s hydrodynamic efficiency.

ENSTA is involved in two aspects of the project, both of which present numerous and highly specialised technical challenges:

• the magnetic attachment system: definition, simulation and testing.
• the robot’s hydrodynamic aspects: modeling and simulation.

In the field of naval hydrodynamics, the work of ENSTA researchers focuses on optimising the robot’s geometry using numerical simulation, in order to minimise the forces it is subjected to. The models developed will also undergo validation tests in ENSTA’s new wind tunnel.

In addition to the involvement of two researchers, two engineers will be recruited on fixed-term contracts for this project.

Led by Subsea Tech in partnership with Naval Group, CMA CGM, the University of South Brittany (LBCM laboratory) and ENSTA (IRDL laboratory), the project will run for 42 months and has a total budget of 5.96 million euros, of which 3.95 million euros is funded by the State under the France 2030 programme, administered by ADEME.