Edgetech 2000-CSS, User Manual

Page: 51 / 101

3-17
To deploy the towfish:
1. With the survey vessel under way at up to two knots, slowly and carefully lower the towfish into
the water, well away from the propeller. Do not let the towfish strike the hull of the survey vessel.
2. Lower the towfish to a depth of about three meters, or just below the propeller wash.
3.
In the DISCOVER 2000-C Dual Frequency Side Scan Main window , click the Transmit tab in the
Lower Control panel, and then select the range for each frequency. This tab is shown in
F
IGURE
3-5 .
4. Click the Bottom Track tab. This tab is shown in F
IGURE
3-8 .
Figure 3-8: Lower Control Panel, Bottom Track Tab—DISCOVER 2000-C
5. On the Bottom Track tab make the required settings to track the bottom and note the towfish
altitude in the Altitude display.
6. Lower the towfish such that its altitude is 10–15% of the range selection.
7. Increase the survey vessel speed to the desired survey speed and adjust the amount of cable out
such that the altitude of the towfish remains at 10–15% of the range selection.
8. If a pressure sensor is installed, verify that the Pressure display indication is correct.
9. Secure the tow cable to the survey vessel.
10. Begin recording data.
3.10 Towfish Recovery
To recover the towfish:
1. In the DISCOVER 2000-C Dual Frequency Side Scan Main window, click the Transmit tab and clear
the High Sonar On and Low Sonar On check boxes. This tab is shown in
F
IGURE
3-5 .
The side scan transducers should stop transmitting.