Simrad PI Spread/Depth sensor Why use this sensor

The current depth of the trawl door is important information for efficient catch.

  • On a bottom or semi pelagic trawl you will need to know when the trawl door hits the bottom.
  • On a pelagic trawl you will need to know the depth of the trawl doors to make sure that your gear is on the same depth as the catch.
  • On a pelagic trawl you need to position the trawl doors on identical depths in order to obtain a good geometry, and to avoid an inclined trawl opening.
  • On a pelagic trawl a door may accidentally surface, for example if you turn the vessel. In darkness or with very long tow lines this may occur without your knowledge. Depth monitoring will prevent this from happening.
  • On any trawl, the balance of the trawl doors may be affected by the sea current. This lack of balance will often cause one or both doors to change depth. This is then easily detected when a sensor is used on one or both doors.

The PI Spread/Depth is placed on the port trawl door, and commonly used with the PI Remote/Depth sensor on the starboard door. This configuration will provide you with the accurate depth of both trawl doors.