The new life of Coustié
Ports & Harbours
In 2004, the main survey vessel Escandail was commissioned with a multibeam echosounder and other hydrographic equipment. However, in 2007, the need for a second vessel, lighter and just as versatile, arose. The Hydrographic Division ordered a catamaran vessel, the Coustié, which was equipped with two powerful 150HP outboard motors, making it long-range and fuel-efficient. Although the catamaran did not initially have specific hydrographic equipment, it was used for various missions such as topographic studies, water and sediment grab samples, turbidity measurements, towed side scan sonar imagery, and hydrographic surveys with a single beam echosounder. The decision to equip the Coustié with a multibeam echosounder was made in 2017. The technology of multibeam echosounders, motion sensors, and associated equipment had significantly improved, becoming more robust, delivering greater performance, and reducing their form factor. The future mission of the Coustié will primarily be multibeam bathymetry in water depths ranging from 0.5m to 80m, as well as quay wall inspection.
Modifying the catamaran was a complex project, which involved cutting a hole in the hull to create a central well in which a vertical telescopic pole supporting the future multibeam echosounder would be submerged. The participation of the "Centre de sécurité des navires" was critical to ensure that none of the alterations would affect the vessel's navigation performances. CADDEN, a company known for the quality of its product offering and its outstanding technical expertise, was awarded the contract for the entire project. The Sonic 2022, a R2Sonic multibeam echosounder, was chosen for its wide operating frequency range, excellent bathymetric resolution, and lightweight. The other systems acquired include an inertial unit with an integrated GNSS compass and RTK, a mini SVS hull speed probe, a PC, a radio modem for precise location, and a generator and an inverter to power all the equipment. The opening of the hull was an emotional moment for all stakeholders, and the installation of the well and metal tubular structure of the telescopic pole and its base generated a lot of enthusiasm within the team.
On August 3rd, 2020, Coustié was launched, and over the following weeks, CADDEN supervised the trials and tests at sea, calibrated the sonar system, and trained the hydrographers on the new equipment. On September 22nd, Coustié performed its first multibeam survey. Now that the Coustié is fully equipped for high-resolution multibeam survey, it will improve the Hydrographic Division's capabilities in various missions, including multibeam bathymetry and quay wall inspection.