Chapter 12 - Alarms, TideTrack, Currents, and Echo Sounding
Page 12-20
2. To remove the echo sounder overlay at any time, press the
OVERLAY key, then press the HIDE 490 key.
For details about using the echo sounder, see the Northstar
490 Echo Sounder Operations Manual (GM490).
961/962 Operations and Reference Manual, Rev. A