Furuno SFD-1010 Operator's Manual page 141

4. MULTI BEAM SONAR DFF-3D
Side scan display
The side scan display shows the echoes received from the port and starboard
directions.
The side scan display starts from the center of the vessel, and traces in the port
and starboard directions. The most recent echoes are at the top of the screen
and the oldest are at the bottom of the screen.
The side scan display is different from the other modes employed by this
equipment – it clearly displays the shape of echoes (fish reef, etc.).
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