Furuno CSH-5 MARK-2 - Manual (Page 34)

28
Sea Surface Reflections
To reduce the sea surface reflections, set the tilt angle to 5
°
or more
so that the upper edge of the sonar beam may not hit sea surface, or
adjust TVG functions. When the sonar is used with a narrow tilt angle,
the sea surface reflections cover large area (up to 300 m to 400 m) as
illustrated below.
SEA SURFACE
Tilt angle 0
°
13
°
SEA SURFACE
Tilt Angle 5
°
- 6
°
13
°
Tilt Angle
Indication
Sea Surface
Reflection
Wake
Awake produced by own ship or another ship can be a strong reflect-
ing object when the sonar is used with a narrow tilt angle. As the
wake appears on the screen as a thick continuous line, it can be easily
distinguished from a fish school. On the other hand, the wake con-
tains a lot of air bubbles which attenuate ultrasonic energy, making it
often difficult to sound beyond the wake.
Tilt Angle : 0 - 10
°
Other Ship
Own Ship
Wake produced
by other ship
Own Ship’s
Screw Noise
Own Ship’s
Screw Noise
Own Ship’s
Wake
Wake produced
by own ship when
ship is turned