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Sonar unit with external temp sensor, external speed sensor, or combo
speed/temp sensor. The primary temperature sensor is built
into the transducer.
Optional Speed Sensor Installation
All the units in this series can display speed and distance traveled, but
only the SeaCharter 640cDF comes packed with a speed sensor. If you
wish to purchase an optional additional sensor for your unit, refer to
the accessory ordering information inside the back cover of this man-
ual. The following instructions describe how to install the speed sensor.
Recommended tools for this job include: drill, 5/8" drill bit, 1/8" drill bit for
pilot holes, screwdriver. Required supplies for this job include: four #8
stainless steel wood screws (3/4" long), high quality, marine grade above-
or below-waterline sealant compound.
First find a location on the boat's transom where the water flow is smooth-
est. Don't mount the sensor behind strakes or ribs. These will disturb the
water flow to the speed sensor. Make sure the sensor will remain in the
water when the boat is on plane. Also make sure the location doesn't inter-
fere with the boat's trailer. Typically, the sensor is mounted about one foot
to the side of the transom's centerline.
Speed or combo
speed/temp sensor.
Sonar unit rear view
Temp
sensor
Temp sensor built
into transducer.
Power/transducer
cable
3-amp fuse
Power/transducer socket
Accessory
socket
GPS antenna
GPS antenna socket