Flow Sensor

Flow Sensor (Speed/Symmetry)

Scanmar has delivered TrawlSpeed/Symmetry sensors for 20 years, and they are absolutely indispensable for those who have begun to use them. More and more open their eyes to how important this combination is for efficient fishing, giving full control over the trawl geometry while assuring optimal towing speed.

Flow Sensor on the headline

All trawls have an optimal water flow rate. It varies according to design, mesh size, thickness of purse line, knots, age of materials and more. Because of underwater currents, the trawl speed will deviate from the vessel’s GPS speed and must be compensated. If the trawl moves too fast through the sea, a bucket effect is created in the trawl, forming an area of pressure ahead of it. If towing is too slow, fish get an opportunity to escape, especially large ones with their greater swimming power and endurance.

Trawl speed and symmetry

The TrawlSpeed function helps you adjust to changes in water flow and maintain the correct towing speed.

The Symmetry function shows if there is a side current into the opening, leading to a skewed trawl, which is very ineffective. Side currents can be caused by wrong warp lengths, underwater currents and towing in hillsides. Unless this is corrected with differing warp lengths, the trawl will not be symmetrical to the water flow. The meshes will then close on one side and be wide open on the other, allowing current and fish to pass through the side panel.