Flow sensors - a new family of current meters

Through use of Scanmar sensors on fishing and research vessels it has been determined that wind, currents, towing direction and towing speed have c rucial meaning for the trawl’s ability to catch.

It has been 25 years since Scanmar launched the combined Trawl Speed /Symmetry sensor. It was obvious at that time that the fishermen were not familiar enough with underwater curren ts and the effect these had on efficient fishing. Fishermen towed according to GPS - speed and trusted the winch producers’ statements that the trawl was correctly towed as long as the warps were equal and pressure on the winch was the same.

The new family Flow sensors consist of combined Trawl Speed /Symmetry sensor, pure Symmetry sensor and Tunnelflow sensor, and a half - brother: the Grid sensor.

Symmetry

If the trawl do es not move symmetrically trough the water current the direction of the water flow (the water flow given from the direction the vessel is moving in and side current) wi ll come a t a skewed angle at the opening. In this situation the whole trawl will be asymmetrical, the mesh on the opposite side of the current will stretch, the water flows through trough the mesh, and fish/shrimp escape.

The Symmetry sensor has twice the work ing time as the combined sensor and can be used alternately by changing the battery.

Asymmetry leads to open mesh and direct loss of catch