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Scanmar's various sensors to cover all your needs. Check out our gallery to the right for quick browsing or select from our list to read details and description for a specific sensor. 


  • Detects fish and shrimp not visible on the vessel’s echo sounder

  • Measures the height of the trawl opening, the height from the headline to bottom, and bottom contact or clearance

  • Enables skippers to optimize the trawl geometry

  • Configurable with diff. ranges on down- and/or upward

  • Includes two batteries


Detection ability of the TrawlEye
Because the TrawlEye is closer to the fish (when mounted on the headline) it has far better detection capacity than echo sounders mounted on the vessel. An experienced skipper will easily be able to tell whether he is seeing fish or bait, and whether he is fishing for the “right species”.


Wide-Beam & Narrow-Beam

With the many areas of application and different fisheries, Scanmar saw the need for two TrawlEye variants; The Wide-Beam TrawlEye was first launched on the market for low opening trawls, and is commonly used in white fish operations.
When fishing for shrimp or other species close to the seabed, the Narrow-Beam TrawlEye usually gives the best detection.
It is also commonly used in pelagic trawling.


Bottom Trawling

The TrawlEye gives precise information about the trawl opening and contact with or clearance from the bottom.
During bottom trawling this information is very useful to avoid losing bottom contact.


Pelagic Trawling

In pelagic trawling Narrow-Beam TrawlEye is most common, both in the trawl opening and in the belly.

Areas of application are even more varied compared to bottom trawling. Many use the TrawlEye as a headline sensor instead of trawl sonar, or as a replacement if the trawl sonar has broken down. It will detect fish, not only in the trawl opening, but also above and under the trawl, and it provides full control of the distance to bottom.

TrawlEye in the belly
The belly is also an important area of application in pelagic trawling. Placed in a net pocket sewed into the centre of the mesh roof at the preferred area of the belly, it shows influx, height and distance from the bottom. Many pelagic trawlers have begun to use an extra TrawlEye in the belly, often together with a FlowSensor or a CatchSensor with an Angle function, in order to ensure that what they see in the trawl opening ends up in the cod-end

User Manual



Flow Sensor


  • Two functions: TrawlSpeed and Symmetry

  • The TrawlSpeed function measures the speed of the waterflow into the trawl opening

  • The Symmetry function measures the side currents into the opening

  • The sensor is used to assure optimal towing speed and trawl symmetry to reduce fuel costs and loss of catch


Flow Sensor (TrawlSpeed / Symmetry) – the sensor that controls the geometry
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 simultaneously assuring optimal towing speed.

Flow Sensor on the headline

All trawls have an optimal water flow rate. This varies according to design, mesh size, thickness of purse line, knots, age of materials, etc. 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” will be created in the trawl, forming an area of pressure ahead of it. If towing is too slow, this will give fish an opportunity to escape, especially large ones, with their greater swimming power and endurance.

The Trawl Speed 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. This will in turn lead to the meshes being closed on one side and wide open on the other, allowing current and fish to pass through the side panel.

Flow Sensor in the tunnel

Because the trawl’s circumference and mesh is smaller further back in the trawl, a lot of the water has to get out through the side panels. This is when a bucket effect occurs, which makes the mesh stretch. If this happens in an area with large mesh the fish escape or the trawl walls will be clogged with fish.
As the cod-end fills up, the bucket effect will increase and move forward within the trawl. This is why we notice that it takes such a long time to fill up the forward end of the cod-end. Generally speaking, it is better to haul in and reshoot.
Using the Flow sensor in the tunnel with the Trawl-Speed and Symmetry function the skipper can monitor the waterflow’s angle and speed to avoid a bucket effect and loss of catch

User Manual



SS4 Door Sensor


  • Multifunctional

  • Increased battery capacity

  • Robust and innovative construction

  • 5 Year warranty


SS4 DoorSensor
An important factor in all kinds of trawling is having control of your trawl doors. Water flow, speed, depth, wire length, bottom conditions and under water currents will affect the performance of your doors and the trawl efficiency

Functions available in the new SS4 Door Sensor:

  • DISTANCE: Door distance, bottom & pelagic trawl

  • DEPTH: Door depth

  • TEMPERATURE: Sea water temperature

  • TENSION: Tension in trawl wires or sweeps

  • ANGLE: Door angle (roll & pitch)

  • STABILITY: Door stability (ScanFactor)

The sensors can be bought with one or several functions, and can be upgraded later via license.


  • User benefits:

  • Adjust and control your rigging to gain optimal door spread

  • Secure optimal and stable door distance during the haul independent of variations in depth, ground conditions, etc.

  • Ensure door spread and avoid doors coming together or twisting during shooting

  • Detect trawl or doors hooking on the bottom

  • Adjust the warps to individually gain optimal and equal spread for door-clump-door

  • See the results of changes to the rigging immediately

  • Allows different rigging for different operations;  shallow or deep, slow or fast, rough or smooth bottom, flat or steep hillsides, different trawls, etc

  • Maximize door performance, so that the trawl fishes optimally with the least possible use of bunkers

  • Detect damages, wear and tear to the doors immediately, repair and continue with optimal performance.

  • Correct angle of the doors, will extend the doors life time and securing an even wear-off of trawl door shoes

  • Observe if the doors are unstable or are about to lose bottom contact by monitoring the doors’ stability

The new design with double casting of the electronics provides 100% protection. Scanmar’s newly developed super plastic drastically reduces damage to the sensor due to strokes, tension, or if doors get hooked on the bottom.

Batteries & Charging
With new long lasting Lithium-ion batteries, charging is in many cases, no longer an issue. Many are able to keep the sensor on the door for the whole trip, and only charge when back from the fishing ground.

User Manual



SS4 Depth Sensor


  • Unmatched data accuracy

  • Negligible operation cost and long lifetime

  • Up to 700 hours of operating time


The DepthSensor is an invaluable tool in trawling and Purse Seine fisheries, providing accurate information of the sinking speed and depth, which enables the skipper to decide when to start trawling/pursing.


  • Purse Seine: one or several sensors on purse line for depth and sinking speed

  • Tuna Seine: two depth sensors with temperature on purse line

  • Pelagic trawl: DepthSensor on the headline with temperature, and one on the cod end

  • Bottom trawl: DepthSensor on the headline, with temperature option

User benefits

  • Position the trawl at correct depth to target a shoal

  • Mounted on the cod end – avoid a sinking bag when hauling a pelagic trawl

  • Know when to start towing in the landing phase

  • Purse seine – watch the sinking speed and depth using one or several DepthSensors

  • Easily programmable for use under various conditions

  •   Add more functionality – upgrade with Temperature and Angle function



The new design with double casting of the electron-ics provides 100% protection. Scanmar’s newly developed super plastic drastically reduces damage to the sensor due to strokes, tension, or dragging along the bottom with a twisted trawl.


Batteries, Charging & Programming

The new batteries have ten times as much capacity as the old batteries. The transmission power in the sensors can be adjusted depending on the depth at which one is fishing. This is something that in most cases, will lead to a further increase in operation time.
The sensor is always ready for use because a quick charge for a haul can be done in minutes, due to the improved battery capacity and increased time between charges.

The new SS4 is a durable multifunctional sensor which can be programmed in several configurations for multipurpose use. It can be upgraded to include other key functions, i.e. Angle (pitch & roll) and sea temperature

User Manual



Trawl Sounder

  • Advanced echo sounder showing fish influx and volume

  • Measures the height of the trawl opening, whether the trawl is on the bottom and the distance between the trawl and the bottom

  • Used in pelagic, bottom trawling as well as Danish/Scottish Seine

  • Ideal to pair with DoorSensors for showing a simplified trawl geometry


Advanced Echo Sounder

The TrawlSounder is an advanced echo sounder showing the height of the trawl opening, if the trawl is on the seabed and the distance between the trawl and seabed.

It also provides a simplified “sonar” that shows whether there is fish influx and the volume. Choose between “classic view” or “density view” on your Bridge System. Wireless monitoring of the trawl opening and intermediate section of the trawl has become a matter of necessity in many of the world’s fisheries.

Mounted in the belly it shows whether the trawl height is stable, or if a bucket effect is arising and allowing fish to escape. It also shows the volume of fish passing through.
Together with a TrawlEye in the opening it is easy to see whether the fish seen entering the opening end up in the cod end.


Trawl Geometry

The TrawlSounder is ideal together with the Door-Sensors and the TrawlSpeed / Symmetry sensor to get full control of the trawl’s geometry.

User Manual



SS4 Catch Sensor

  • SuperCatch, filling indicator, up/down, temperature and rip functions

  • 5 year warranty

  • Up to 1500 hours of use from one charge


Scanmar SS4 CatchSensor meets all the requirements any fisherman could have

Catch function

The sensors Catch function is activated with the stretch wire when the trawl is filled to the point where the sensor is mounted, which enables the skipper to follow the gradual filling. The SuperCatch function has a faster update-rate, showing a quicker activation, which is particularly important to avoid overfilling.


Filling Indicator (Angle) function

Indicates the filling rate using both pitch and roll angle measurements on the cod end.
The Pitch measurements show how the bag gradu­ally fills up to the point where the sensor is mounted.
The Roll angle (twist) shows how the bag twists when it begins to fill and how it gradually corrects itself when it becomes full. The sensor can be programmed for normal or quick updating.


Up/Down function
The Up /Down function will notify the user when the cod end twists and is being towed upside down.


Rip function
When using the Rip function the sensor is mounted in the belly of the trawl and will alert the user if detecting any rips or tears in the net to prevent loss of catch and potentially costly damage.Construction
The new design with double casting of the electron­ics provides 100% protection. Scanmar’s newly developed super plastic drastically reduces damage to the sensor due to strokes, tension, or dragging along the bottom with a twisted trawl. 

Batteries, Charging & Programming
With new long lasting Lithium-ion batteries, charging is no longer an issue. Most users are able to keep the sensor on the net for the whole trip, and only charge when back from the fishing ground.
Transmission power and FID are easily programmed with the new programming unit/charger, alongside with choosing fast or normal update rate.
The charger has features that can check both battery and sensor status

User Manual



Height/Depth Sensor

  • Provides reliable information about the position and the movement of the seine at all times

  • Increases the catch efficiency and reduces the danger of tearing the seine


The Depth measurement shows distance to the surface and is used to monitor the sinking speed and the position of the seine in water. The Height measurement shows distance to the bottom and helps the skipper place the seine closer to the bottom and start to haul at the right time in the launch phase.


The new sensor is developed specially for purse seiners and is a stronger and more robust version of the classic combination sensor for purse-seiners. The electronics is moulded into the same resilient plastics as in the SS4 generation of sensors. This protects against damage. In addition, the sensor body is reinforced with Kevlar-reinforcements. The sensor withstands a stretch of 6 tons and is Scanmar’s strongest sensor ever! Included is the specially designed mounting kit with great rupture strength

User Manual



Grid Sensor

  • Used to fish more efficiently with grid Measures the grid’s angle, indicating the catch volume

  • Shows if the waterflow through the grid is blocked, resulting in loss of catch

  • Applicable for bottom and pelagic trawls


The aim was to fish for shrimp in fields with many small fish, but without taking the latter as a by-catch. In many countries there are regulations regarding trawling, and in some areas it is mandatory to use a grid in the cod end.

Use of GridSensor
The Scanmar GridSensor was developed to show the precise water flow through the grid, and also the grid’s angle. The angle will give you a good indication of the filling in the cod end, and if the trawl has twisted.


Water Flow
Water flow through the sorting grid is the most important observation. Not infrequently, the grid becomes blocked by skate, seals, shark, stones etc. In some seasons, big swarms of jellyfish seal the meshes in the cod-end, preventing water from flowing out. In these cases it is neccessary to end the haul.


Grid Angle
Changes to the angle give a good indication of the catch volume at any time, and the logging curve also shows where the influx was greatest.
With shrimp (and fish without a swim bladder), the cod-end sinks as it fills up. It is therefore usual to start with an angle above 50 degrees and to finish towing when the angle approaches 37 or 38 degrees

User Manual



Clump Sensor

  • Provides accurate distance between clump(s) and both doors on twin and triple trawls

  • Multifunctional: Distance, Angle, Depth, Temperature, Tension and Bottom contact

  • Robust construction and plastic protects against damage and wear

  • Up to 700 hrs operation time on clump Quick charging


Extended distance measurements

To avoid asymmetry when fishing with twin or triple trawl it is important that doors and clump are in line. Information about the doors’ and clump’s position in relation to each other is therefore essential.

User benefits

Traditionally distance measurements on twin and triple trawls have been based on the assumption that doors and clump(s) are in line. With the previous Door sensor and a transponder the distances from door-to-door and clump-to-port door have been measured, while the distance clump-to-starboard door has been estimated from the measured distances. However, this estimation is only correct when the clump is in line with the doors.

Scanmar’s new and extended distance measurement gives the exact distance between door-to-door, doors-to-clump and clump-to-clump on triple trawls. The clump’s actual position in relation to the center line is measured independently of the length of the wire, side currents etc.

With the help of accurate distance measurements and information from the Symmetry sensor, the skipper is able to optimize the trawl’s geometry by adjusting the lengths of the wires, so that doors and clump are in line, also in areas with side currents. The data is presented graphically on the Scanmar bridge system.

The sensor can also be used as a bottom contact sensor with a special mounting kit, or to measure the distance between the trawl wings.

Available functions


  • Distance -   Distance to both doors and clump(s), distance between trawl wings

  • Depth -   Clump depth

  • Temperature -  Sea water temperature

  • Tension - Tension in wires

  • Angle - Clump angle (roll & pitch)

  • Stability -   Clump stability (Scan Factor)

  • Bottom contact -  Distance from gear to bottom

The double casting of the electronics provides 100% protection. Scanmar’s newly developed super plastic drastically reduces damage to the sensor.

Batteries & Charging
With new long lasting Lithium-ion batteries, charging is in many cases no longer an issue

User Manual



Door Height Sensor

  • The Door Height Sensor is a cable based module for the SS4 Door Sensor.

  • Uplink and power are provided by the connected Door Sensor.



User Manual