Amphibian UWILD: remote robotic platform for underwater inspection in lieu of drydocking

Marine biofouling, caused by accumulation of plants, algae and animals on ship hulls, increases hydrodynamic drag, reducing speed and fuel efficiency. It also increases loading on the hull structure which can cause corrosion and crack formation that will lead to eventual failure of the hull structure (J Mater Sci, 2022).

Ocean-going **vessels require corrosion and defect inspection and certification** every 1-5 years, depending on vessel age, defect history and countries where they operate: **12 months (UK MCA and EU PSC directive)**; **4 years (Transport Canada)**; **3-5 years (US Coastguard)**.

**Conventional cleaning and inspections** are carried out by dry-docking the ship, but this is being **gradually replaced by UWILD** solutions: Under Water in Liu of Drydocking. UWILD currently relies on surveys using divers which are inherently unsafe, while diving crew costs, vessel rental, fuel and weather disruptions all contribute greatly to project costs. There is an **increasing demand for safer inspections** using Drones and ROVs **but these are limited** to either above or below water operations and can't operate in the in-between splash zone. They are also subject to buffeting by waves and ocean currents which limits their detection to spot readings in areas where there is visual confirmation of corrosion or defects.

Emerging **robotic technology** that clings to the hull **has the potential to provide more accurate inspection in all weathers, both above and below the waterline**. The robotic crawler uses magnetic wheels or tracks to stick to the surface. However, difficulties in controlling the robots when they are out of sight under the ship hull means there is a pressing need to develop an **autonomous navigation** system to ensure accurate and consistent data is recorded on the location and severity of corrosion and other defects on the ship hull.

Our solution, **Amphibian UWILD provides a safe, technology-driven, cost-effective robotic UWILD solution** that will **drive down project costs** for the thousands of vessels that require periodic and statutory underwater inspections. This will include autonomous guidance and localisation, avoidance of obstacles such as hull sensors or side thrusters and will enable exact positioning to provide continuous data points from a range of NDT sensors (Ultrasonics, Eddy-current, EMAT etc), down to 1mm apart, to accurately identify and report the location of defects on a large ship hull.