1
Use a 43 mm (1
11
/
16
in.) hole saw to cut through the hull at
the mounting location.
2
Insert the thru-hull fitting in the hull.
3
Apply marine sealant to the outer flange of the thru-hull fitting
and tighten the nut by hand.
4
Slide both rubber O-rings onto the plug.
5
Apply silicone grease to the outside of the plug.
6
Using a slow, twisting motion, insert the plug into the thru-hull
fitting.
7
Verify that the plug is properly seated into the fitting.
8
Mount the fitting with the pin at a 90 degree angle to the
centerline of the boat.
9
After the marine sealant applied in step 3 has cured, remove
the nut and apply sealant on the fitting inside the hull.
10
Replace the nut and tighten it by hand.
11
After installation of the fitting, replace the plug with the actual
transducer.
NOTE:
It is recommended that you keep the plug for use
while cleaning or servicing your transducer.
12
Install the wire locking device onto the transducer.
Preparing a Cored-Fiberglass Hull
NOTICE
If the core of a cored-fiberglass hull is not sealed properly, water
may seep into the core and severely damage the boat.
À
Fiberglass or casting epoxy (not included)
Á
Cylinder spacer (not included)
Â
Inner fiberglass skin
Ã
Core
Ä
Outer fiberglass skin
1
Drill the hole through the hull.
2
Seal the core inside the hull using either fiberglass (
) or casting epoxy (
).
Drilling a Hole in a Cored-Fiberglass Hull
1
From inside the boat, drill a 3 mm (
1
/
8
in.) pilot hole
completely through the hull.
2
Examine the pilot hole on the outside of the boat, and select
an option:
• If the pilot hole is not in the correct location, seal the hole
with epoxy and repeat step 1.
• If the pilot hole is in the correct location, use a 43 mm (1
11
/
16
in.) hole saw to cut a hole from the outside of the
boat through the outer fiberglass skin only. Do not cut
completely through the hull.
3
On the inside of the boat, at the pilot hole location, use a hole
saw to cut a hole 9 to 12 mm (
3
/
8
to
1
/
2
in.) larger than the
hole you cut in the outside of the boat in step 2.
Cut through the inner fiberglass skin and most of the core,
without cutting the outer skin.
NOTE:
When cutting the inner fiberglass skin and core, be
careful to not cut the outer fiberglass skin, or you will not be
able to correctly seal the hull.
4
Remove the inner fiberglass skin and core you cut in step 3.
You should be able to see the inside of the outer fiberglass
skin.
5
Sand the inside of the hole and the areas immediately around
both the inside and outside fiberglass skin.
6
Clean the area using a mild detergent or weak solvent, such
as isopropyl alcohol, to remove any dust and dirt.
Sealing the Hull 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 the
correct diameter of 43 mm (1
11
/
16
in.).
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
To properly seal the core with casting epoxy, you must create a
cylinder with a diameter of 43 mm (1
11
/
16
in.) to act as a spacer
as the epoxy sets.
1
Coat a 43 mm (1
11
/
16
in.) cylinder with wax.
2
Insert the cylinder in the hole through the outer skin and tape
it in place on the outside of the boat.
3
Fill the space between the cylinder the core with casting
epoxy.
4
After the epoxy has hardened, remove the cylinder, and sand
and clean inside and around the hole.
The cored-fiberglass hull is now prepared, and you can
complete the transducer installation.
NMEA 2000
®
Connection
The transducer connects to the network on your vessel. The
GDT 43 connects to the NMEA 2000 network through the thru-
hull Intelliducer
™
device.
À
Thru-hull Intelliducer
Á
GDT 43 transducer
2
