Furuno GP-7000F - Manual (Page 13)

7
Thru-hull mounting
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 turbulence 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 a sounder is directly related to the mounting location of the transducer, espe-
cially 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 submerged, 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)
28
22
120
68
30
520-5PSD
24
120
68
90
520-5MSD
Unit: mm