Activ-Omni Intelligence

Notus sensors boast an active, two-way communication system, not offered by other net monitoring systems. Instead of relying on traditional one-way pingers, Notus systems ‘talk’ to each other via proven two-way protocols. Using this reliable technology, Notus is the ONLY system capable of delivering trawl wire lengths with doorpsread of EACH net, giving a true geometric view of the gear.

Variable data rates: 5, 10, 20 and 60 second intervals

Notus is the only system to offer true, omnidirectional pattern beams in all of our net monitoring sensors. This is critical when turning, when a door has fallen over or when fishing gear is lost.

With Notus Activ-Omni Intelligence, achieve optimal performance, for superior results

Notus Sensors



Pictured: Twin Trawls + Door Spread

Doorspread is the distance between the doors on EACH net.

Major fuel savings are achieved with doorspread by adjusting the speed of the vessel to keep the optimal spread.
For example, towing just 0.1 knots too fast into a current can overspread the gear by 10 meters.

Doorspread for EACH net for twin & multi trawls

Pictured: Twin Trawls + Door Spread

  • Indicates when doors have crossed

  • Permits equal bilk on EACH net

  • Detects when door has fallen or is stuck.

  • Instantly see if a rock, pot or other debris is in the trawl

  • Notus has the only omnidirectional sensors on the market.
    Doorspread is provided on a turn with one door 100 meters behind the other


Pictured: Twin Trawls + Trawl Warp Measurement

Trawl Wire Lengths – Made possible by Activ-Omni Intelligence

By measuring EACH set of trawl wires to within 0.1 meter, the Notus Trawlmaster:

  • Avoids measuring trawl wires on shore

  • Indicates the adjustment in cross current to "square" the doors

Doorspread and trawl wire lengths are standard Trawlmaster sensors. These sensors can be upgraded to include door depth, door angle and temperature.

Middle Wire Adjustment

Pictured: Twin Trawls + Middle Wire Adjustment

The middle wire adjustment is calculated to align the middle weight (clump) with the doors in twin rigs

Middle wire adjustment indicates:

  • When the clump is ahead of the doors, the trawls overspread

  • When the clump is behind the doors, the trawls under-spread, which can lead to gear damage

The Notus Trawlmaster Middle Wire Adjustment indicates the exact middle wire adjustment to align the clump with the doors, to ensure optimal fishing!


Pictured: Twin Trawls + Depth And Temperature

Depth sensors indicate the distance from the surface to the middle weight or clump.

The Clump Depth sensor:

  • Ensures the clump remains on bottom.

  • Indicates when too little wire out or when towing too fast has caused the clump to come off bottom


Pictured: Twin Trawls + Door Angle

Door angle sensors provide the heel angle (inward/outward lean) and pitch angle (upward/downward pitch).

  • Set the trawl doors for optimal spread and optimal fuel consumption

  • Instantly indicate if too much trawl wire is shot as the door heels over

  • Confirm when doors are on bottom

Temperature Sensor

Pictured: Twin Trawls + Depth and Temperature

Temperature sensors indicate temperature wherever the sensor is located.

  • Locate larger schools by trawling in the right temperature range

  • Target specific species.

  • Determine where the fish are


Pictured: Twin Trawls + Headline Height

Headline Height sensors use an echo sounder to measure the distance from the headline to the seafloor. An optional footgear clearance sensor can be added to monitor the net opening and footgear clearance.

  • Raise and lower headline depending on species and trawling conditions

  • Indicate if the trawls are raising off the bottom due to towing too fast

Catch Sensor

Catch sensors indicate when the cod-end has a set amount of fish. Multiple sensors can be used to indicate different amounts of fish.

Notus Trawlmaster Catch sensors:

  • Confirms that the trawls are fishing

  • Only take back what you can handle onboard

  • Prevents hauling back trawls that are only half full

  • Provides a better indication of exactly where the fish are in the tow

  • Has a built-in gear location feature should you lose the trawls or just the cod-end

  • Improves fish quality

  • Prevents gear damage associated with over-filling the nets

Grid/Grate Sensor

Pictured: Twin Trawls + Grid Angle

Grid sensors indicate angle of the sorting grid.

Notus Trawlmaster Grid sensors:

  • Are a necessity on any grid

  • Confirm that if the grid is not at the right angle, nothing goes to the cod-end

  • Indicate if your grid is blocked

  • Estimate catch volume by monitoring downward trend of grid angle

  • Instantly indicate if the grid is incorrectly rigged

Bottom Contact Sensor

Pictured: Twin Trawls + Bottom Contact Sensor

Bottom Contact sensors confirm that the trawls are on bottom using angle measurements. The sensor is attached to the fishing line and remains horizontal when the trawls are on bottom. The sensor orientates in a vertical position when the trawls comes off bottom.

  • Fishing is greatly reduced once the trawls comes off bottom

  • Indicates if the speed into the current is taking the trawls off bottom

  • If there is not enough trawl wire shot, the trawls will not be on bottom.

  • Overspreading the trawl doors can also result in the trawls coming off bottom


Pictured: Twin Trawls + Wingend Spread

The Wingend Spread sensor provides the distance between the two wingends.

Notus Trawlmaster Wingend sensors confirm:

  • Keeping the optimal wing spread can be just as important as doorspread

  • Wingspread is a critical piece of information for researchers in calculating swept area.