No longer sold

Simrad DFS75

The Simrad DFS75 is an innovative and advanced trawl sonar.

The DFS75 allows you to monitor the fish activity inside your fishing gear using a high-resolution colour sonar and echo sounder.

The DFS75 trawl sonar is provided as a natural extension to the Simrad FX80 catch monitoring system, which also provides a live video feed.

Key features

  • Revolutionizes your ability to identify, analyse and catch
  • Live video feed from inside the trawl (FX80)
  • Video recording, editing, export and playback (FX80)
  • High-resolution colour sonar and echo sounder images
  • Choose between 120 or 330 kHz operational frequency
  • Add hydrophones to communicate with PS, PI and PX catch monitoring sensors
  • Add a transducer to provide additional echo sounder presentation
  • Uses standard 3rd wire cable
  • The small and light-weight system offers easy installation
  • Easy operation using familiar graphic interfaces

Simrad DSF75

This screen capture (in replay) shows the opening of a bottom trawl. On the middle view you can easily see the trawl opening and the flat bottom. On the left view, the optional built-in optional echo sounder shows the depth variation of the bottom. Both single fishes and schools are easily detected due to the high operating frequency used by the trawl sonar.

System description

A real-time video feed from the trawl has long been desired by fishermen and researchers alike. Cabling and slip-rings have been the issue. One of the primary design criteria of the Simrad FX80/DFS75 system was to make it work on existing 3rd wire cables. We have achieved this goal using copper core coax cables. The use of existing copper core coax cables eases the cost and reduces the installation time.

The Simrad DFS75 Trawl sonar is integrated into the Simrad FX80 system to establish an efficient and accurate monitoring system for your gear and your catch. The combination of the high resolution images from the trawl sonar and the live video feed provides you with an unparalleled opportunity to identify and analyse both trawl movements and fish behaviour.

The entire Simrad FX80/DFS75 system - with live video and high resolution sonar - is controlled from a standard Processor Unit provided by Simrad. It is small, but yet powerful, and contains no moving parts. The system design will allows you to use two displays. Many users prefer this configuration, as it allows them to use one display system for the trawl sonar presentations, and another for the live video feed.


A typical DFS75 display presentation is shown. Two views are provided, an Sounder view on the left hand side (A), and a Vertical view on the right hand side (B). In this example, the Vertical view is set to presentation mode Net opening. This example has been made in Playback mode with previously recorded data. For this reason, certain presentation elements are not shown. The menu options also reflect the chosen operational mode.

(A) Sounder view - You can change the size of each view by clicking the border line between them and move it sideways.
(B) Vertical view - In order to do changes in a view, you need to ‘activate’ it. To do that, click once in the view, or click the View button at the top of several menus.
(C) Menu - A large menu system is offered to maintain full control of the DFS75 operation. Choose which menu to use by clicking the tabs at the right hand side. Note that the parameters provided by certain menus depend on the current view and presentation mode.
(D) Trawl Deployment Unit - This is a real-time presentation of the DFS75 Trawl Deployment Unit movements and behaviour.
(E) Trawl Deployment Unit sensors - The DFS75 Trawl Deployment Unit holds sensors to record its depth and movements, as well as the ambient temperature.
(F) Catch monitoring sensors - If Simrad catch monitoring sensors are used with the DFS75 system, the information from these sensors are provided here.
(G) Operating mode and help - The System button provided allows you to choose operational mode. The Help button opens the on-line help.
(H) Recording toolbar - A dedicated toolbar is provided to allow fast access to key functions related to recording and playback. To enable the toolbar, click Rec.Toolbar on the Display menu.

Status bar and Message Log - When enabled, a dedicated toolbar is provided to allow fast access to key functions related to navigation markers. To enable the toolbar, click Status bar on the View menu. The Message Log will – when opened – place itself at the bottom of the DFS75 presentation. To open (and close) the Message Log, click Message Log on the View menu.

System diagram


(A) Colour display (two displays may be used)
(B) Processor Unit (personal computer)
(C) Bridge Control Unit
(D) 3rd wire (commercial, not included in delivery)
(E) Trawl Deployment Unit (holds the Communication Hub and the Sonar Head)
(F) 4th wire
(G) FX80 Camera Unit (video camera and lamp)

The number of displays must be chosen to fit the preferences of the crew. Many users prefer separate displays for the trawl sonar and the live video feed. Colour displays are not included in the standard delivery from Simrad. These are commercial items that can be purchased locally.

The winch system on the trawl deck and the 3rd wire cable must also be provided by a third party manufacturer.


Services and support

  • 24/7 Technical support

    Our 24/7 technical support team is there to help at any time, day or night, wherever your vessel is.

  • Conversions, retrofit and refit

    We understand the importance of having the right parts, available in the right place, at the right time.

  • Training

    Ensure that your crew is properly and thoroughly trained. This will reduce operational risk, downtime and maximise return on asset investment.