Furuno FSV-85 User Manual

2. HORIZONTAL MODE
2-43
2.22.2 Unnecessary echoes
Sea surface reflections
To reduce sea surface reflections, set the tilt angle to 4° or higher, so the upper edge
of the sonar beam does not hit the sea surface, or adjust TVG. When a decreased tilt
is used, sea surface reflections cover a large area as illustrated below.
Wake
A wake produced by own ship or another ship can be a strong reflecting object when
a decreased tilt angle is used. As the wake appears as a thick continuous line, it can
be easily distinguished from a school of fish. A wake contains many air bubbles which
attenuate ultrasonic energy, making it difficult to sound beyond the wake.
Sea surface
Sea surface
10
°
Tilt angle
indication
Sea surface
reflections
10
°
Tilt: 0
°
Tilt: 4
°
-5
°
Own
ship
Other
ship
Wake produced
by other ship
Own ship's
screw noise
Own ship's
screw noise
Own ship's wake
(produced when
own ship turned)

Furuno FSV-85 Specifications

General

Brand	Furuno
Model	FSV-85
Category	Sonar
Language	English