Interphase iScan V90 Operation Manual page 15

Mount Transducer so bronze stem is Vertical
Waterline
Hull
Transducer
Waterline
Fairing
Block
Hull
Boat's
Hull
DO NOT install a bronze transducer housing directly into an
aluminum or steel hull because electrolytic corrosion will
occur. Consult your boat-yard for more information on how to
properly install transducers into these types of hulls.
IMPORTANT:
Keep parallel
1) Make sure the water flow across the thru-hull transducer is
to waterline !
bubble and turbulence free at all speeds if good performance is
to be achieved.
2) Make sure the transducer has an unobstructed view of the
water ahead and 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 bronze nut will
Forward
require tightening from inside the hull.
Because the iScan V90 scans a 12 degree beam from the
Bronze
surface ahead to directly below the boat, it is important to make
Hex Nut
sure that the transducer is installed so that it will scan in a
vertical direction and not off to either side. 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.
Keep parallel
Use of a Thru-hull Fairing Block
to waterline !
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, mahogany, or plastic
Wood or
and should be glued between the transducer and hull (both
Plastic
inside and outside) to insure that the transducer's mounting
Fairing Block
shaft is perpendicular to the water's surface. Make the fairing
(Add sealing
block as smooth as possible, and not bigger than the
compound
transducer's face, to minimize possible turbulence.
between
After cutting the fairing block, trial fit the block to the hull. It
faring block
is very important that the flat top surface of the transducer be
& hull)
parallel to the water. Because of the skills involved, your
professional boatyard provide the fairing block.
Installing the Thru-hull Transducer
1) Drill a 1/8" pilot hole from inside the hull to assure access
to tighten the housing nut and clearance for the transducer
Transducer
cables. If there is any hull irregularity near the mounting
location, it may be desirable to drill from the outside.
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