Application Notes
Application Notes


With the wide range of instruments that OSIL represent, they pride themselves in being able to provide complete solutions to the many marine and environmental problems that their clients present them with.  When GEMS, Geotechnical Engineering and Marine Surveys, approached OSIL with an urgent requirement for a low cost, dredge monitoring system that they needed to be ready to ship within a week, their reaction was no different.


OSIL decided that with the short time scale and low cost specification, YSI’s EMM375 Compact Monitoring Buoys would be the ideal solution to GEMS problem.  OSIL offer a series of buoys which range from a buoyancy of 175lbs to 2000lbs.  The different features attributed to each buoy means that whatever the requirements, OSIL can deliver a buoy to suit the application.  Each buoy provides mounting for telemetry and data acquisition electronics, meteorological sensors, solar panels and antennae and much more.


YSI EMM375 Low-Cost Buoy in Fos Sur Mer Port
YSI EMM375 Low-Cost Buoy in Fos Sur Mer Port


OSIL selected two YSI EMM375 Buoys as the solution for GEMS as they are specifically designed for monitoring around dredge sites and are very reasonably priced.  The buoys are unaffected by chemicals, solvents and fuel in such situations and are very robust.  They can be fitted with an array of instruments and with a small diameter of nominally 1 meter they are easy to transport and install for rapid deployment.

The GEMS buoys

The GEMS buoys


The buoys were delivered to OSIL who then performed a turnaround within 24 hours, which involved fitting the buoy with waterproof housing containing electronics, a YSI multiparameter sonde, batteries and a warning lamp.  Richard Davies of GEMS verifies, “we are very happy with the turnaround OSIL were able to provide.”


The installation of the buoys was performed by GEMS in the Fos Sur Mer Port in France.  The buoys were installed to enable both background and real-time turbidity data to be collected around a dredge barge.  This is in line with the port authorities dredge compliance monitoring requirements.  A YSI 6600 Sonde was used to monitor the turbidity, temperature and salinity of the water just below the surface.


The data collected by the sonde was telemetered back in real-time providing the client, Dredging International, with real-time data via both the internet and, more importantly, SMS text message directly to the barge.  This system enables the levels to be monitored and if they are seen to rise above the background of 50mg/l then the dredging operation can be temporarily halted to keep in line with the legislation.


One of the buoys in Fos Sur Mer Port
One of the buoys in Fos Sur Mer Port


As well as observing the dredging effects, the buoys can also be used for general environmental protection monitoring.  In this case they are also being used to monitor around commercially sensitive oyster beds situated in the port.  The first buoy was positioned near the dredging operations, while the second was deployed next to the oyster beds ensuring that they were not affected by the dredging activity.


Richard Davies explains why GEMS looked to OSIL to provide the instant solution for their client, “we work closely with OSIL and enjoy a strong working relationship.”  At this current stage GEMS can report that they have a “very happy client” and that “the buoys have been very cost-effective, allowing us to add value by fitting out for this project.”


For further information on OSIL’s capabilities and range of data buoys please contact:

Culkin House
C8 Endeavour Business Park
Penner Road
Tel: +44 (0)2392 488 240
Fax: +44 (0)2392 488 241


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