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The SIRENE is effective at a relative current speed in the range 0.5 knots to 3 knots.
The most common configurations are as follows:
in a river or an estuary
* from one bank to the other
* from one bank with spinnaker boom
* from one bank to anchorage on mooring posts
* on 2 anchorages
close to a fuel wharf
in the high seas
* 1 SIRENE with 2 light boats
* 1 boat with 1 SIRENE and 1 floating tank
* 1 boat with 2 SIRENE with spinnaker boom or paravane
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The THOMSEA small net was designed for coastal waters, harbours or sheltered waters and can be towed by a boat that is at least 4 metres long and 30 hp. The filtering cod-end is able to contain 1.7 tons of crude oil or debris before it has to be hoisted. It can be reconditioned and reused very quickly, after about 20 minutes.A special version has been created for oyster boats and Mediterranean fishing boats with a collecting capacity of 2.3 tons. Imagine a fleet of 40 to 50 oyster boats, each equipped with a THOMSEA net. These seamen have a local knowledge that makes it difficult to envisage a better protection for oyster beds and shellfish farms.
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During the PRESTIGE oil spill, fishermen, using the THOMSEA nets under orders from the Navy, managed to prevent more than 2,400 tons of heavy oil from reaching the French coast, without getting oil on themselves or on their boats.
Since 2003, the Navy has adopted the THOMSEA concept and trains several times a year with fishermen using the THOMSEA nets. The large THOMSEA net can be towed by one or two boats that are at least 12 metres long and 150 hp.
The filtering cod-end is able to contain 8 tons of crude oil or debris before it has to be hoisted. It can be reconditioned and reused very quickly, after about 30 minutes.
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Putting together a fleet of fishermen, oyster farmers and mussel farmers is vita! as a first line of defence from sea pollution. However, simple common sense would dictate that we plan for a second line of defence to protect the more vulnerable and precious areas, such as estuaries, oyster beds, protected zones, etc. It was with this thought in mind that we designed an adapted form of the THOMSEA net - a channel net. which can be fixed in position and which uses the force of tidal currents to collect heavy oil and debris arriving in an estuary. This net is held in place by stakes on each of the river banks (maximum 50 metres apart) and can collect up to 5 tons. The currents at high tide carry the waste to the filtering cod-end. which automatically closes when the tide goes out. thereby retaining the pollutant until the next tide comes in and the collecting process can start again.
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