Deployment and Recovery of Instruments
The study of underwater areas sometimes requires the use of measuring instruments placed on the seabed. These are most often left underwater for periods ranging from several weeks to several months.
For this reason, it is essential not to leave any trace on the surface (buoy).
Principle
In order to deploy correctly and in the appropriate position, the measuring instruments are extended by a gantry at the rear of the ship.
In order to know precisely the position of the device, mainly used for its recovery, it is important to georeference the precise point of deployment.
Deployment
The Ceres Team is used to working in areas of high tidal range, with significant currents and has good expertise in this field.
The deployment is carried out on a theoretical point most often provided by the client.
However, CERES is able to provide bathymetric and sonar maps to find the best site option.
Installation on a wreck
The main problem with instrument deployment being the heavy activity of dredging and trawling, CERES proposes to deploy the instruments directly on wrecks.
The installation and retrieval are then carried out by the team of divers.
CERES has a very large database on shipwrecks in the English Channel.
Recovery
The recovery is most often carried out using an acoustic release system. A code is sent from the boat, which releases a buoy inside the cage.
The buoy is then spotted and retrieved on board.
The instrument is then raised using the ship's hydraulic winch.
However, the drop system occasionally fails. CERES then offers the option of using a team of divers for recovery. This method can be kept as an alternative, in case the drop does not work as planned.