Testing on the Water
1. With the beam angle factory-set to 90
°
, 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
sensor’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, its position probably needs adjustment.
The sensor is probably in aerated water.
IMPORTANT
: To improve performance, try the following, one at a
time, in the order given.
a. Increase the sensor’s transom angle in the water. Review
“Compensating for Transom Angle: Shims” and see Figure 4.
b. Move the sensor farther into the water in increments of 3mm
(1/8") (see Figure 3).
c. Move the sensor closer to the centerline of the boat.
Fill unused screw holes with marine sealant.
Stabilizing the Bracket
Stabilize the bracket by installing the third bracket screw at the
bottom of the center slot (see Figure 5). Using a 4mm, #23, or
9/64" drill bit, drill a hole 22mm (7/8") deep.
Apply marine sealant to the threads of the third #10 x 1-1/4" self-
tapping screw to prevent water seepage into the transom. Tighten
the screw.
Releasing the Bracket
The sensor releases easily when it is fastened to the hull. Give a
sharp blow to the bottom of the sensor using the palm of the hand.
Cable Routing & Connecting
CAUTION
: If the transducer came with a connector, do not
remove it 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 through the transom, choose a location
well above the waterline
(see Figure 3). Check for obstructions
such as trim tabs, pumps, or wiring inside the hull. Mark the
location with a pencil. Drill a hole using the appropriate size bit
to accommodate the connector.
2. Route the cable over or through the transom.
3. On the outside of the hull, secure the cable against the transom
using the cable clamps. Position one cable clamp 50mm (2")
above the bracket and mark the mounting hole with a pencil.
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 marked locations, use a 3mm or 1/8" bit to drill a
hole 10mm (3/8") deep.
7. Apply marine sealant to the threads of the #6 x 1/2" self-tapping
screws to prevent water from seeping into the transom.
If you
have drilled a hole through the transom, apply marine sealant to the
space around the cable where it passes through the transom.
8. Allowing an extra 76mm (3
"
) of cable ease near the sensor, position
the two cable clamps over the cable and fasten them in place. If
used, push the cable cover over the cable and screw it in place.
9. Route the cable to the instrument being careful not to tear the
cable jacket when passing it through the bulkhead(s) and other
parts of the boat. Use grommets where appropriate. To reduce
electrical interference, separate the sensor cable from other
3
Figure 5. Stabilizing the bracket
13
°
transom angle
14
°
–17
°
angle
Figure 4. Adjusting the sensor’s angle
20
°
transom angle
3
°
transom angle
parallel
slight angle
4.5
°
shim
4.5
°
shim
with taper
with taper up
angle
slight angle
9
°
shim
with taper
nearly parallel
May improve operation
above 20kn (23MPH)
May improve operation
above 20kn (23MPH)
more angle
9
°
and 4.5
°
shims with
more angle
May improve operation
above 20kn (23MPH)
down
tapers down
down
May improve operation
above 20kn (23MPH)
4.5
°
shim
with taper
down
more angle
Copyright © 2008 Airmar Technology Corp.
Copyright © 2008 Airmar Technology Corp.
stabilizing
screw