Sea Surface Reflections - Furuno CSH-5 MARK-2 Operator's Manual

Tilt angle 0
Tilt Angle 5 - 6 13
Other Ship
Own Ship
Own Ship's
Screw Noise
Tilt Angle : 0 - 10

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
13
SEA SURFACE
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.
Wake produced
by other ship
28
Wake produced
by own ship when
ship is turned
Own Ship's
Screw Noise
Tilt Angle
Indication
Sea Surface
Reflection
Own Ship's
Wake