Sonic 2024 supports Cristobal Colon

With the increasing size of the dredging equipment, the tasks they face become more and more extreme. In unsheltered offshore conditions at waterdepth over 100 m close to existing live infrastructure tight tolerances have to be met. The Belgian Jan de Nul group, one of the world leading dredging contractors, deployes the Jumbo dredger Cristobal Colon on just such a project on the North Sea. A pipeline trench has to be made. Auxilary vessels for survey are not practical and the world largest hopper dredger, 46.000 m3 hopper capacity and an overall length of 220 meter, has to multitask: dredger and surveyvessel.



Obviously survey system components had to be chosen carefully with respect to capacity, accuracy and reliability. For this task the Sonic 2024 was chosen and installed in a moonpool through the vessels hull. The unique features of the Sonic systems did make the use of ROV systems obsolete:

• Proven use of 400 kHz and high resolution characteristics up to waterdepth of 120 meter
• The ability to switch to lower frequency on the fly when 400 kHz absorption appears to become to high at greater waterdepth (fall back scenario)
• The system ability to focus all beams in narrow sector of 10 degrees to increasing the bottom definition density in the trench structure
• The system ability to rotate the sector on the fly to keep the beams on the target even if the vessel deviates from the line

Though the works are still in progress first results appear to be promising. The Sonic 2024 is living up to its expectations and is capable to provide accurate data for the working process.
The first surveylines show high definition data of the existing infrastructure at a waterdepth of appr 110 meter.