Clever buoys track oil slicks
The AIS Drifting Buoys have been used to track remnant oil slicks. Photo: NASA.
In May 2008 Aanderaa Data Instruments AS (AADI) entered an agreement with The Norwegian Clean Sea Association for Operating Companies (NOFO) to develop a small drifting buoy that has similar drift characteristics as an oil slick on the sea surface.
During another oil spill exercise at the Frigg Field in the North Sea during early summer the AIS Drifting Buoys were used to track remnant oil slicks that were escaping from the main spill. This involved directing a reconnaissance airplane returning to the Frigg Field to locate and map the leftovers from the oil recovery exercise that was conducted.
Information from the drifting buoys, which have a diameter of approximately 30 cm, is transferred by AIS and displayed on the electronic chart system onboard any vessel that has up to date ECDIS software according to IMO standards.
According to the design specifications, the vessels should be able to pick up the AIS signals from the buoy at a distance of at least three nautical miles. Tests have shown that good signals were picked up at a distance of seven nautical miles with wave heights of 10m, and 12 nautical miles on a calm sea. Drop tests confirmed that the buoy will withstand a drop from the specified altitude of 50m above sea level, which makes it possible to drop from a fixed installation or from a helicopter.
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