Operation Manual

Operational procedures
83
850-165186 / Rev.B
Access to the marker line parameters
1 Make sure that a Graphic display presentation is active.
2 Press the ADJ button to open the Graphic setup
dialogue.
3 Press the GAIN+ button until the Marker line setup
dialogue appears.
4 Observe the list of sensors. Only the sensors capable of
providing data for marker lines are listed.
Trawl calculator
In order to calculate the correct delay, we suggest that you use
the built-in Trawl calculator. Observe the following procedure:
1 Press the GAIN+ button to access the Trawl calculator
setup page.
2 Set Trawl calculator mode to Auto.
3 Set Towing speed to Auto.
- In order to retrieve speed information, the relevant
equipment (GPS) must be interfaced to your P I54.
- When you read the speed information from a GPS, the
information is very accurate. Due to the fact that the
trawl calculations are made continuously, even the
slightest change in speed will be reflected on the
display presentation, and you may experience that the
markers fluctuate. If this is a problem, enter the
average vessel speed manually.
4 If you run a pelagic trawl, set Trawl depth to Manual,
and enter the mean depth.
5 If you run a bottom trawl, you can set the Trawl depth to
Bottom, and read the depth from the echo sounder.
- If a transducer is connected to the PI54, the trawl
calculator will update the delay based on the data from
the echo sounder.
6 Enter the Wire length. In most cases, this is the length
from the stern of the vessel to the trawl doors.
7 Enter the Wire length offset. This is the distance from the
trawl doors to the headrope, and normally a fixed value.
The calculator will add the wire length to the wire length
offset, and use the sum of these in the calculations.