Interphase Advantage User Manual page 15

d. Mount the transducer on the side of the hull where the
propeller is moving downwards. The upward motion of
Suggested Thru-Hull
the propeller generates pressure waves and
Transducer Locations
pushes bubbles up against the hull which can then flow
across the transducer's face causing a loss of signal.
DO NOT install a bronze transducer housing directly into
an aluminum or steel hull because electrolytic corrosion
will occur.
IMPORTANT:
1) Make sure the water flow across the thru-hull
transducer is bubble and turbulence free at all speeds if
good performance is to be achieved.
2) Make sure the transducer has an unobstructed view of
Fin Keel
the water below the boat.
3) On displacement-hull power boats, the transducer
should be mounted relatively close to the center line of
the hull.
4) Mount the transducer in a place which has reasonable
access from inside the vessel since the transducer's speed/
temperature plug will need to be removed from time to
time. Also, during installation, the bronze nut will require
tightening from inside the hull.
The transducer must be mounted so that it's bronze stem
is as perpendicular to the water line as possible. If
necessary, use a fairing block to properly position the
transducer.
Use of a Thru-hull Fairing Bl
ock
Displacement Hull
Nearly all vessels have some dead rise angle at the
transducer mounting location. If the thru-hull transducer
were mounted directly to the hull, the sound beam would
be tilted off the vertical at the same angle as the dead-rise.
Most thru-hull installations will require a fairing block to
insure the transducer is mounted properly.
A fairing block is typically made of teak or mahogany
wood or plastic and should be glued between the
transducer and hull (both inside and outside) to insure that
the transducer's mounting shaft is perpendicular to the
water's surface. Make the fairing block as smooth as
possible, and not bigger than the transducer's face, to
minimize possible turbulence (see next page).
Planing Hull
15