6
Installation in a Cored Fiberglass Hull
The core (wood or foam) must be cut and sealed carefully. The
core must be protected from water seepage, and the hull must be
reinforced to prevent it from crushing under the hull nut allowing
the transducer(s) to become loose.
CAUTION
: Completely seal the hull to prevent water seepage
into the core.
1. Drill a 3mm or 1/8" pilot hole perpendicular to the waterline from
inside the hull (Figure 8). If there is a rib, strut, or other hull
irregularity near the selected mounting location, drill from the
outside. If the hole is drilled in the wrong location, drill a second
hole in a better location. Apply masking tape to the outside of the
hull over the incorrect hole and fill it with epoxy.
2. Using the appropriate size drill bit/hole saw, cut a hole from
outside the hull through the outer skin only. Be sure to hold the
drill plumb, so the hole will be perpendicular to the water surface.
3. The optimal interior hole diameter is affected by the hull’s
thickness and deadrise angle. It must be large enough in
diameter to allow the core to be completely sealed.
4. Using the drill bit/hole saw for the hull interior, cut through the
inner
skin and most of the core from inside the hull keeping the
drill perpendicular to the hull. The core material can be very
soft. Apply only light pressure to the drill bit after cutting through
the
inner
skin to avoid accidentally cutting the
outer
skin.
5. Remove the plug of core material so the
inside
of the outer skin
and the inner core of the hull is fully exposed. Sand and clean
the inner skin, core, and the outer skin around the hole.
6. Coat a hollow or solid cylinder of the correct diameter with wax
and tape it in place. Fill the gap between the cylinder and hull
with casting epoxy. After the epoxy has set, remove the cylinder.
7. Sand and clean the area around the hole, inside and outside, to
ensure that the sealant will adhere properly to the hull. If there
is any petroleum residue inside the hull, remove it with either
mild household detergent or a weak solvent (alcohol) before
sanding.
8. Follow the same procedure to prepare the hull for each anti-
rotation stud/screw (steps 1 through 6).
9. Proceed with “Bedding” on page 4.
Cable Routing & Connecting
CAUTION
: Do not remove the connector(s) to ease cable routing. If
a 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.
1. Refer to the instructions that came with the echo sounder module
to connect it to the display and the power supply.
2.
Transducer Pair
—Connect the starboard transducer to the short
cable on the port transducer. Rout the longer cable on the port
transducer to the echo sounder module (Figure 9).
Maintenance, Parts & Replacement
Anti-fouling Coating
Surfaces exposed to salt water must be covered with an anti-
fouling coating. Use a
water-based
anti-fouling coating made for
transducers only. Never use ketone based paint, since ketones
can attack many plastics possibly damaging the transducer. Brush
on anti-fouling coating every 6 months or at the beginning of each
boating season.
Checking for Leaks
When the boat is placed in the water,
immediately
check around
the transducer(s) for leaks. Note that very small leaks may not be
readily observed. Do not leave the boat in the water for more than
3 hours before checking it again. If there is a small leak, there may
be considerable bilge water accumulation after 24 hours. If a leak
is observed, repeat “Bedding” and “Installing”
immediately
.
Cleaning
Aquatic growth can accumulate rapidly on the transducer’s
surface reducing its performance within weeks. Clean the surface
with a Scotch-Brite® scour pad and mild household detergent
taking care to avoid making scratches. If the fouling is severe,
lightly wet sand with fine grade wet/dry paper.
hull’s outer skin to
hull
outer skin
solid or hollow
cylinder
pour in
casting
epoxy
core
inner skin
Figure 8. Preparing a cored fiberglass hull
dimension equal to
the thickness of the
ensure adequate
clearance
Copyright © 2005 Airmar Technology Corp.
Figure 9. Cable routing transducer pair
Copyright © 2022 Airmar Technology Corp.
steep deadrise hull
with two transducers
starboard
transducer
port
transducer
echo sounder