Inspection & Monitoring

Independently of the domain of application, all underwater works are generally characterised by the same difficulty, i.e. the impossibility to make observations of an ongoing job in the same way as onshore.

Inspection by divers has many drawbacks. Besides many safety issues, limited diving periods, strong currents, low (or no) visibility, the underwater situation is also assessed in a subjective way. This lack of an objective tracking limits strongly the quality of the inspection.

Most often quantitative information with relatively high precision is required (e.g. current state of a quay wall). In this respect, it might be more economic and appropriate to use dedicated underwater visualisation tools to provide results which respond the best to our Client’s requests. These techniques have many advantages:

  • Reasonably fast installation on a vessel of opportunity.

  • Quick, accurate (mm to cm) and safe underwater measurements in harsh environments with high noise levels, turbidity, tidal current, waves, etc.

  • An online monitoring of the underwater situation and tracking its evolution with time. Measurements can be done in real-time on 2D or 3D video images or on 3D geo-referenced point clouds.

  • A large inspection range and an economic coverage of (large) survey zones.

  • An online monitoring of moving targets which offers the possibility to a crane operator to follow-up the ongoing operations beneath the water level, independent of the visibility in the water column.

In order to select the most appropriate techniques, many different parameters are taken into account:

  • Type of inspection or monitoring
  • Dimensions of the zone to be surveyed
  • Required resolution
  • Static or dynamic targets
  • Local site conditions (current / turbidity / water depths)
  • Online image (no processing) and ease of interpretation by e.g. a crane operator
  • Available nautical means (ship size / ROV / AUV)

G-tec has a large experience in deploying the following visualisation techniques:

  • Video camera
  • Laser Scanner
  • Imaging Sonar
  • Side-Scan Sonar
  • EchoscopeTM
  • Multi-beam echo-sounder with 3D modelling
Inspection & Monitoring G-tec