Inspecting floating wind turbine mooring chains

Industry: Renewables

Location: Mediterranean Sea

Hydro: Hydro 300 | ROV: PERSEO | Depth: 90m

Context

Floating offshore wind is gaining momentum in the Mediterranean, creating new inspection and integrity management needs for mooring systems. They are critical to the integrity of floating offshore structures. Making regular inspection and dimensional monitoring is essential to assess their condition, check corrosion and other forms of degradation.
The Hydro 300 from the Hydro Series was used to perform a photogrammetric survey of selected mooring chain sections on a floating wind turbine in the French Mediterranean Sea. The objective was to generate accurate 3D reconstructions and perform dimensional measurements on areas showing wear or degradation.

IVM Solution

At the Provence Grand Large offshore wind farm, the Hydro 300 photogrammetry system was integrated onto an inspection-class ROV and deployed to inspect three selected areas of the turbine’s mooring system.

The survey reached depths of up to approximately 90m. Despite the range of operating depths, the complete 3D acquisition was carried out within a single day, with less than two hours of photogrammetric acquisition time. Around 40,000 images, representing 344GB of data, were collected during the survey.

The captured data was then processed to generate dense point clouds and textured 3D meshes of the three inspected areas, giving the inspection team a detailed digital representation of the chain links for further analysis. Measurements included chain-link diameter and grip dimensions, with dimensional reports produced for links inspected at both 30 m and 90 m depth. The dimensional control reports were issued with a stated general tolerance of ±0.5 mm.