Eagle 128 Installation And Operation Instructions Manual page 15

Align transducer centerline with hull bottom and attach to transom.
6. Route the transducer cable through or over the transom to
the sonar unit. Make sure to leave some slack in the cable at the
transducer. If possible, route the transducer cable away from other
wiring on the boat. Electrical noise from the engine's wiring, bilge
pumps, VHF radio wires and cables, and aerators can be picked up by
the sonar. Use caution when routing the transducer cable around
these wires.
WARNING:
Clamp the transducer cable to the transom close to the
transducer. This can prevent the transducer from
entering the boat if it is knocked off at high speed.
If you need to drill a hole in the transom to pass the connector through,
the required hole size is 5/8".
Caution:
If you drill a hole in the transom for the cable, make sure it is
located above the waterline. After installation, be sure to seal the
hole with the same marine grade above- or below-waterline
sealant used for the mounting screws.
7. Make a test run to determine the results. If the bottom is lost at
high speed, or if noise appears on the display, try sliding the
transducer bracket down. This puts the transducer deeper into the
water, hopefully below the turbulence causing the noise. Don't allow
the transducer bracket to go below the bottom of the hull!
Flat-bottom hull
Bottom
of
hull
Deep-"vee" hull
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