Airmar S61—Transom Mount - Manual (Page 3)

3
Cable Routing
CAUTION: Do not remove the connector to ease cable routing. If
the cable must be cut and spliced, use Airmar’s splash-proof
Junction Box No. 33-035 and follow the instructions provided.
Removing the waterproof connector or cutting the cable, except
when using a water-tight junction box, will void the sensor
warranty.
Route the sensor cable over the transom, through a drain hole or
through a new hole drilled in the transom above the waterline.
1. If a hole must be drilled, choose a location well above the
waterline. Check for obstructions such as trim tabs, pumps or
wiring inside the hull. Mark the location with a pencil. Drill a hole
through the transom using a 20mm or 13/16” hole saw or spade
bit (to accommodate the connector).
2. Route the cable over or through the transom.
3. On the outside of the hull secure the cable to the transom using
the cable clamps. Position a cable clamp 50mm (2") above the
bracket and mark the mounting hole with a pencil (see Figure 6).
4. Position the second cable clamp halfway between the first
clamp and the cable hole. Mark this mounting hole.
5. If a hole has been drilled through the transom, open the
appropriate slot in the cable cover. Position the cover over the
cable where it enters the hull. Mark the two
mounting holes.
6. At each of the four marked locations, use a 3mm or 1/8" bit to
drill a hole 10mm (3/8") deep. [To avoid drilling too deeply, wrap
masking tape around the bit 10mm (3/8") from the point.]
7. Apply marine sealant to the threads of the four #6 x 1/2" self-
tapping screws to prevent water from seeping into the transom.
If you have drilled a hole in the transom, apply marine sealant to
the space around the cable leading through the transom.
8. Position the cable clamps and screw them in place. If used,
push the cable cover over the cable and screw it in place.
9. Route the cable to the instrument through the interior of the
boat. Be careful not to tear the cable jacket when passing it
through the bulkhead(s) and other parts of the boat. To reduce
electrical interference or “noise”, separate the sensor cable
from other electrical wiring. Coil any excess cable and secure it
in place with zip-ties to prevent damage.
10.Refer to your instrument owner’s manual to connect the sensor
to the instrument.
Checking for Leaks
When the boat is placed in the water, immediately check for
leaks around the screws and any holes drilled in the hull. Note
that very small leaks may not be readily observed. Do not leave
the boat in the water unchecked for more than three hours.
Testing on the Water
1. Become familiar with your echosounder’s performance at a
speed of 4kn (5MPH).
2. Gradually increase the boat speed and observe the gradual
decline in performance due to turbulent water flowing over the
transducer’s active surface.
3. If the decline in performance is sudden (not gradual), identify
the boat speed at which the onset occurred. Return the boat to
this speed, then gradually increase speed while making
moderate turns in both directions.
4. If the performance improves while turning to the side on which
the sensor is installed, the transducer’s position probably needs
adjustment. It is probably in aerated water.
To improve performance, try the following one at a time in the
order given.
a. Increase the sensor’s angle in the water with a shim.
b. Move the sensor closer to the centerline of the boat.
Fill unused screw holes with marine sealant.
NOTE: High-speed operation [above 35kn (40MPH)] may
require less projection in the water to improve performance and
reduce the chance that water pressure will cause the bracket to
release.
5. Calibration—To match the speed shown on the display to the
actual speed of the boat, you may need to calibrate the
instrument. Refer to your instrument owner’s manual.
Figure 6. Routing the cable
cable cover
cable clamps
50mm (2")