Sealing the Core with Fiberglass
1
From inside the boat, coat a layer of fiberglass cloth with
fiberglass resin and place it inside the hole to seal the core.
2
Add layers of fiberglass cloth and resin until the hole is
25 mm (1 in.) in diameter.
3
After the fiberglass has hardened, sand and clean inside and
around the hole.
The cored-fiberglass hull is now prepared, and you can
complete the transducer installation.
Sealing the Core with Casting Epoxy
1
Coat the included 25 mm (1 in.) cylinder with wax.
2
From outside the boat, insert the cylinder into the hole, and
tape it in place on the outer surface.
3
Fill the space between the cylinder and the core with casting
epoxy.
4
After the epoxy has hardened, remove the cylinder, sand and
clean inside and around the hole.
The cored-fiberglass hull is prepared, and you can complete
the transducer installation.
Applying Marine Sealant to a Thru-hull Transducer
You must apply marine sealant to the water path to ensure a
tight, waterproof seal between the transducer and hull.
Apply a 2 mm (
1
/
16
in.) layer of marine sealant to the flange of
the housing that will contact the hull, and up the sidewall of
the housing.
NOTE:
The sealant must extend 6 mm (
1
/
4
in.) above the top
of the hull to seal the hull and secure the hull nut.
Installing the Transducer in a Fiberglass Hull
It is recommended that two installers complete these
instructions, with one positioned outside the boat and one inside
the boat.
NOTE:
When installing a transducer in a fiberglass hull, avoid
over-tightening the nuts to prevent damaging the hull.
1
From outside the hull, insert the transducer
À
through the
mounting hole, using a twisting motion to squeeze out excess
sealant.
2
From inside the hull
Á
, slide the rubber washer
Â
, nylon
washer
Ã
, and hull nut
Ä
onto the stem.
3
Use slip-joint pliers or a crescent wrench to hold the stem,
and secure the hull nut to the transducer stem.
Do not over-tighten the hull nut.
4
Before the sealant hardens, remove all excess sealant on the
outside of the exterior hull to ensure smooth water flow over
the transducer.
Non-cored/Fiberglass/Wooden Boat Hull
Installation Instructions
Drilling a Hole in a Non-Cored Hull
1
Select a mounting location (
).
2
Drill a 3 mm (
1
/
8
in.) pilot hole from outside the hull.
3
If the vessel has a fiberglass hull, place masking tape over
the pilot hole and surrounding area outside the hull to prevent
damage to the fiberglass.
4
If you taped over the pilot hole, use a utility knife to cut out
the hole in the tape.
5
While holding a 25 mm (1 in.) spade bit plumb, cut a hole
from outside the hull at the stem hole location.
6
Sand and clean the area around the hole.
Applying Marine Sealant to a Thru-hull Transducer
You must apply marine sealant to the water path to ensure a
tight, waterproof seal between the transducer and hull.
Apply a 2 mm (
1
/
16
in.) layer of marine sealant to the flange of
the housing that will contact the hull, and up the sidewall of
the housing.
NOTE:
The sealant must extend 6 mm (
1
/
4
in.) above the top
of the hull to seal the hull and secure the hull nut.
Installing the Transducer in a Fiberglass Hull
It is recommended that two installers complete these
instructions, with one positioned outside the boat and one inside
the boat.
NOTE:
When installing a transducer in a fiberglass hull, avoid
over-tightening the nuts to prevent damaging the hull.
1
From outside the hull, insert the transducer
À
through the
mounting hole, using a twisting motion to squeeze out excess
sealant.
2
From inside the hull
Á
, slide the rubber washer
Â
, nylon
washer
Ã
, and hull nut
Ä
onto the stem.
3
Use slip-joint pliers or a crescent wrench to hold the stem,
and secure the hull nut to the transducer stem.
Do not over-tighten the hull nut.
4
Before the sealant hardens, remove all excess sealant on the
outside of the exterior hull to ensure smooth water flow over
the transducer.
Metal Boat Hull Installation Instructions
Drilling a Hole in a Metal Hull
1
Select a mounting location (
).
2
From outside the hull, drill a 3 mm (
1
/
8
in.) pilot hole through
the hull.
The hole must be perpendicular to the water surface.
3
Using a 32 mm (1
1
/
4
in.) hole saw, cut the stem hole from
outside the hull.
4
Sand and clean the area around the holes.
Applying Marine Sealant to a Thru-hull Transducer in
a Metal Hull
You must apply marine sealant to the water path to ensure a
tight, waterproof seal between the transducer and hull.
1
Apply a 2 mm (
1
/
16
in.) layer of marine sealant to the flange of
the housing that will contact the hull, and up the sidewall of
the housing.
3
