Biofouling on ship hulls is a long time and well-known challenge that has a direct impact on vessels drag and fuel consumption, representing more than 600 M€ of extra expenses per year for the maritime industry and consequently very significant additional gas emissions. Besides, not cleaned fouling on long haul vessels fosters the spreading of invasive species, which may be harmful to local marine life. This has resulted in more and more stringent regulations in some countries willing to preserve their marine environment.
Detecting very early stages of Level of Fouling (LoF 0-1, thin slime) is essential as it already increases vessel drag but can be cleaned with a soft method avoiding damaging the hull coating. This approach means that the detection and cleaning system has to be very cost effective and user friendly to avoid increasing the maintenance expenses for the ship owners.
The ambition of the SleekShip project is to propose a novel approach to ship hull cleaning by allowing early detection of this biofouling and cost-effective and soft cleaning of the hulls using a single unmanned underwater robotic system specially designed to reach the objectives both in terms of technical performance and production costs.
The SleekShip consortium has 5 partners, two high tech SMEs: Subsea Tech (SST - France) specialized in underwater robotics, QCell (QCL - Greece) focusing on hyperspectral imaging, one Research Centre: TWI Hellas (THL - Greece) working on navigation control and two end users: M.Danchor (MDR - Israel) a diving company dealing with ship hull maintenance and DANAOS (DNOS - Cyprus) a container ships manager.
The SleekShip technical work programme is articulated around four technical developments:
- An underwater hyperspectral camera capable of capturing optical information in different wavelengths moving beyond the visible spectrum and thus detecting very low levels of fouling. Besides, the hyperspectral technology performs better than standard RGB cameras in turbid waters and this will allow inspection in usually murky harbour environments.
- A cavitation jetting system modified to be integrated on a light underwater robotic system, allowing cleaning operations without damaging hull coatings. Such a system is complemented by a debris suction and filtering device to avoid spreading the fouling in the environment, as required by many national regulations.
- A specially designed underwater robot or ROV (Remotely Operated Vehicle) capable of supporting both the hyperspectral imaging camera and the cleaning tool with a production cost under 30 k€ per unit to compete efficiently with diver operations.
- A semi-automatic navigation software with cruise control algorithms to enhance the performance of the system and relieve the ROV operator from tedious piloting tasks. Such software will upgrade the ROV into a SAUV (Supervised Autonomous Underwater Vehicle) using a set of internal and external navigation sensors.
