Furuno FCV-620 - Manual (Page 36)

4. INSTALLATION
27
4.2 Thru-hull Mount
Transducer
Transducer mounting location
The thru-hull mount transducer (520-5PSD,
520-5MSD) provides the best performance of
all, since the transducer protrudes from the
hull and the effect of air bubbles and turbu-
lence near the hull skin is reduced. When the
boat has a keel, the transducer should be at
least 30 cm away from it. Typical thru-hull
mountings are shown in the figure on the next
page.
The performance of this sounder is directly
related to the mounting location of the trans-
ducer, especially for high-speed cruising. The
installation should be planned in advance,
keeping the standard cable length (8 m) and
the following factors in mind:
• Air bubbles and turbulence caused by
movement of the boat seriously degrade
the sounding capability of the transducer.
The transducer should, therefore, be
located in a position where water flow is the
smoothest. Noise from the propellers also
adversely affects performance and the
transducer should not be mounted nearby.
The lifting strakes are notorious for creating
acoustic noise, and these must be avoided
by keeping the transducer inboard of them.
• The transducer must always remain sub-
merged, even when the boat is rolling,
pitching or up on a plane at high speed.
• A practical choice would be somewhere
between 1/3 and 1/2 of the boat's length
from the stern. For planing hulls, a practical
location is generally rather far astern, so
that the transducer is always in water
regardless of the planing attitude.
Thru-hull mount transducer mounting
dimensions (millimeters)
Acceptable transducer mounting
locations
Suitable transducer mounting locations
28
22
120
68
30
520-5PSD
24
120
68
87
520-5MSD
Unit: mm
z Position 1/2 to 1/3 of the hull
from stern.
z 15 to 30 cm off center line
(inside first lifting strakes.)
z Within the wetted bottom area
z Deadrise angle within 15 °
DEEP-V HULL
HIGH SPEED-V HULL