Description
Simrad manufactures a great variety of wireless multifunction catch monitoring sensors. Using one or more wireless catch monitoring sensors placed in your trawl doors and/or fishing gear, you will get real time
monitoring information of the gear and its behaviour.
By default, a PX family sensor can make 2 measurements. The specific measurements a sensor can make depend on its lid type, its physical location on the gear, and on the type of
receiver you use.
Battery status measurement
When working with wireless sensors, it is vital to know the current level of battery.
Catch measurement
The catch measurement provides you with an “eye” at the codend. You can easily monitor the filling rate and the amount of fish in the trawl.
Use the catch measurement to:
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Adjust the catch volume according to the production capacity. |
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Check that the trawl is fishing. |
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Adjust the catch volume to secure quality. |
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Minimize the towing time to save fuel. |
Clearance measurement
In a trawl gear, clearance is the vertical distance from the footrope to the sea bottom. Clearance is calculated by substracting the opening value from the height value.
Depth measurement
Depth measurements provide you with accurate information about the current depth of the sensor. If you for example place the sensor behind the headrope, you will be able to monitor the depth of the headrope.
By having a sensor measuring depth, you can monitor the exact depth of the gear relative to the surface, and adjust the trawl
depth accordingly. During seining, with the depth measurement you can monitor the depth of the net, and the descending speed of the net. When the sensor is mounted on a Danish Seine, the depth measurement helps you monitor the sinking speed of the net, and it
will tell you when to start hauling once the net has stopped sinking.
Flow measurement
In catch monitoring terminology, the flow measurement presents the speed of the water current entering the trawl opening.
Different species swim at different speeds. When you know the water speed (flow) in the trawl’s opening or the tunnel in real time, you can increase or decrease the vessel
speed to adjust to the target species.
Geometry measurement
When using bottom and pelagic trawl – or twin trawl – the geometry measurement is vital to measure if the trawl is skewed. Then, you can correct the geometry by adjusting the warp lengths
With a danish seine, the geometry measurements will allow you to detect variations in the distance from the centre of the
headrope to either wing due to the net being stretched. You can also detect differences in the rope lengths when the seine is closed (when closed, the distance between the wings
will be close to zero).
Height measurement
Height is the distance from the bottom and up to wherever the sensor is physically located.
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Place the sensor behind the headrope to know the Height and Geometry measurements. |
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With a sensor behind the footrope you will know at once if the trawl sinks closer to the bottom. |
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With a sensor mounted vertically on the footrope of a purse seine, you will know the remaining distance (height) from the
bottom. |
Opening measurement
The opening of a trawl is the vertical distance from the headrope to the footrope.
Pitch and roll measurements
Knowing the roll and pitch angle values are of great importance to have full control of your trawl doors and your gear. With these two measurements you can make real time adjustments to properly align your trawl.
Spread measurement
The purpose of the spread measurement is to establish the distance between the trawl doors or wings. In twin trawl monitoring, spread is also measured between port door and the clump.
Correct door spread is important in order to obtain the correct sweep-angle, as this ensures optimal trawl performance.
Temperature measurement
The temperature layers in the water are changing constantly, and for this reason the temperature must be monitored constantly. Knowing the exact sea water temperature while you are fishing is very important to avoid wasting time and money.