Airmar T42 Technical Document

17-437-01 r02 06/07
CAUTION : NEVER USE SOLVENTS!
Cleaners, fuel, paint, sealants, and other products may
contain strong solvents, such as acetone, which attack
many plastics greatly reducing their strength.
High-precision Temperature Sensor
with NMEA 0183 Data Converter
Model T42
Applications
• Bronze housing recommended for fiberglass or wood hulls.
• Never install a bronze housing in a metal hull because
electrolytic corrosion will occur.
•
Never install a metal housing in a vessel with a positive ground
system.
• The hull must be a minimum of 8mm (5/16”) thick at the
mounting location.
Tools & Materials
Safety goggles
Dust mask
Electric drill
Drill bits: 3mm
or 1/8"
21mm or 7/8"
Sandpaper
Mild household detergent or weak solvent (alcohol)
Marine sealant (suitable for below waterline)
Slip-joint pliers
Installation in a cored fiberglass hull (see page 2)
Hole saw for hull interior: 30mm or 1-1/4"
Cylinder, wax, tape, and casting epoxy
Pencil
Cutting pliers
Wire strippers
Electrical tape
Phillips screwdriver
Alcohol
Blade screwdrivers
Water-based antifouling paint (
MANDATORY IN SALT WATER )
Sensor Installation
Cored fiberglass hull —Follow separate instructions on page 2.
Choose a location where the sensor will be in contact with the
water at all times.
Hole Drilling
Warning : Always wear safety goggles and a dust mask.
1. Drill a 3mm or 1/8" pilot hole from inside the hull. If there is a rib,
strut, or other hull irregularity near the selected mounting
location, drill from the outside.
2. Using the 21mm or 7/8” drill bit, cut a hole perpendicular to the
hull from outside the boat.
3. 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.
Record the information found on the cable tag for future reference.
Part No._________________Date___________
IMPORTANT : Please read the instructions completely
before proceeding with the installation. These
instructions supersede any other instructions in your
instrument manual if they differ.
INSTALLATION INSTRUCTIONSOWNER’S GUIDE &

Bedding
Caution : Never pull, carry, or hold the sensor by the cable as this
may sever internal connections.
Remove the hull nut (see Figure 1). Apply a 2 mm (1/16") thick
layer of marine sealant around the lip of the housing that will
contact the hull and up the stem. The sealant must extend 6mm
(1/4") higher than the combined thickness of the hull and the hull
nut. This will ensure that there is marine sealant in the threads to
seal the hull and hold the hull nut securely in place.
Installing
1. From outside the boat, thread the cable through the mounting
hole.
2. Push the sensor into the mounting hole using a twisting motion
to squeeze out any excess sealant (see Figure 1).
3. From inside the hull, slide the hull nut onto the cable. Screw the
hull nut in place. Tighten it with slip-joint pliers.
Wood hull —Allow for the wood to swell before tightening.
Cored fiberglass hull —
Do not over tighten, crushing the hull.
4. Remove any excess marine sealant on the outside of the hull to
ensure smooth water flow over the sensor.
Checking for Leaks
Warning : DO NOT leave the boat in the water unchecked for
several days.
When the boat is placed in the water, immediately check around
the thru-hull sensor for leaks. Note that very small leaks may not
be readily observed. Do not to 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 (see page 2).
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 housing to become loose.
Warning : Always wear safety goggles and a dust mask.
1. Drill a 3mm or 1/8" pilot hole from inside the hull. 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 21mm or 7/8" drill bit, cut a hole from outside the hull
through the
outer skin only (see Figure 2).
3. From inside the hull using the 30mm or 1-1/4" hole saw, cut
through the
inner skin and most of the core. The core material
can be very soft. Apply only light pressure to the hole saw after
cutting through the inner skin to avoid accidentally cutting the
outer skin.
4. Remove the plug of core material so the inside of the outer skin
and the inner core of the hull is fully exposed. Clean and sand
the inner skin, core, and the outer skin around the hole.
Caution : Completely seal the hull to prevent water seepage into
the core.
5. 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.
6. 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.
7. Proceed with “Bedding” and “Installing” (see page 2).
2
Figure 2. Preparing a cored fiberglass hull
inner skin
core
outer skinsolid or hollow cylinder
pour in
casting
epoxy
9-12 mm
(3/8-1/2")
larger than the
hole through the
hull’s outer skin
hull thickness
Figure 1. Bedding and installing
hull nut
hull
bedding
Copyright © 2005 Airmar Technology Corp. Copyright © 2005 Airmar Technology Corp.

Connecting
Locating the Data Converter & Routing the Cables
Caution : Minimize electrical interference by separating the sensor
cables from other electrical wiring and sources of noise.
Caution : Be careful not to tear the cable jackets when passing
them through the bulkhead(s) and other parts of the boat.
1. Select a convenient dry mounting location for the water-resistant
Data Converter. Locate it a minimum of 1m (3') away from the
display (see Figure 3). Position the converter so the bushings
are easily accessible. If the Data Converter will be mounted on
a vertical surface, be sure the bushings are facing downward to
avoid water seeping into the box. Hold the Data Converter at the
selected location and mark the holes for the screws.
Do not
fasten it in place at this time.
2. Route the sensor cable from the temperature sensor to the
Data Converter.
Do not fasten the cable in place at this time.
3. Route the Data Converter cable from the Data Converter to the
instrument (and power source). Do not fasten the cable in place
at this time.
Wiring the Instrument (& Power Source)
Some installations will connect to the power source within the
instrument. Other installations require wiring to a separate power
source located near the instrument.
WARNING : If the instrument is connected to a power source, the
power must be “OFF” before proceeding.
1. Allowing an extra 25 cm (10") for wiring ease, cut the instrument
cable to length.
2. If the power source is separate from the instrument, strip the
cable jacket and expose the two twisted pairs of wires (see
Figure 4). Strip the outer insulation from each pair.
3. Strip 10mm (3/8") of insulation from each of the four colored
wires making up the pairs.
4. Cut off the bare wire flush with the cable jacket.
5. Protect the cable’s foil shielding from causing a short by
wrapping electrical tape around the jacket where the wires
emerge from the cable.
Be sure the tape overlaps the wires a
minimum of 6mm (1/4").
6. Connect the cable to the instrument following the instructions in
your owner’s manual (see Figure 3). Use the color code below:
White NMEA + A
Blue NMEA – B
7. Connect the power supply. It will either be within the instrument
or a separate power source. Use the color code below:
Red 12 VDC +
Black 12 VDC –/ground
Connecting the Sensor to the Data Converter
If your sensor came with a connector, plug it into the Data
Converter. If your sensor does not have a connector, follow the
instructions below.
1. Allowing an extra 25 cm (10") for wiring ease, cut the sensor
cable to length.
2. Remove the cover of the Data Converter. Peel the tape away
from the inside and set the screws aside.
3. Push approximately 200mm (8") of the sensor cable through
the bushing of the Data Converter (see Figure 5). To ease
sliding, apply alcohol to the cable jacket.
4. Strip 60mm (2-1/2") of the outer jacket and foil shielding from
the cut end.
3
remove some
cable
jacket
remove
of insulation
Figure 4. Preparing the cut end of the Data Converter cable
electrical
tape
cut off
bare wire
Copyright © 2005 Airmar Technology Corp.
Figure 3. Connecting to the instrument
power
source
instrument
Copyright © 2007 Airmar Technology Corp.
red 12 VDC +
black 12 VDC –/ground
white NMEA +A
blue NMEA –B
insulation from
from colored
wires
10mm (3/8")
twisted pairs
to expose
colored wires:
blue
white
red
black
colored wires
twisted pair:
twisted pair:
and a separate power source
(some installations) (not to scale)
Data Converter
1
2
3
4
5
6
7
8
Figure 5. Connecting the sensor to the
Copyright © 2007 Airmar Technology Corp.
Data Converter (some installations)
sensor
cable
bushings
temp +
temp –
blue
black
terminal function wire color
4
8
instrument
cable
sensor
cable
Data Converter

AIRMAR
®
TECHNOLOGY CORPORATION
35 Meadowbrook Drive, Milford, New Hampshire 03055-4613, USA
■
www.airmar.com
4
Copyright © 2005, 2007 Airmar Technology Corp. All rights reserved.
5. Strip 10mm (3/8") of conductor insulation from the end of each
colored wire.
6. Cut off the bare wire flush with the cable jacket.
7. Protect the cable’s foil shielding from causing a short by
wrapping electrical tape around the jacket where the wires
emerge from the cable. The tape
must overlap the wires a
minimum of 6mm (1/4").
8. From outside the Data Converter, carefully pull the sensor cable
until only 13mm (1/2") of the cable jacket remains inside the box.
9. Connect each colored wire in turn to its corresponding terminal
on the terminal block (see Figure 5). Following the color code
listed on the inside of the Data Converter cover, insert the
stripped end of the wire into the hole in the terminal and tighten
the screw using a small blade screwdriver.
Be sure the stripped
end of the wire is inserted up to its insulation only
. Do not
include any insulation inside the terminal. Gently tug on the wire
to ensure that it is securely fastened. Repeat this process until
all the wires are connected.
10.Arrange the wires neatly inside the Data Converter, being sure
that no bare wires are touching.
11.Hand-tighten the nut on the bushing to make a water-resistant
seal.
12.Reattach the Data Converter cover with the screws supplied.
Completing the Installation
1. Using a 3mm or 1/8" drill bit, drill the holes for the screws at the
selected Data Converter mounting location.
2. Fasten the Data Converter using the four screws supplied.
3. Fasten all the cables in place.
Maintenance & Replacement
Aquatic growth can accumulate rapidly on the sensor’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.
Antifouling Paint
Surfaces exposed to salt water must be coated with antifouling
paint. Use water-based or mineral spirits-based antifouling paint
only.
Never use ketone-based paint since ketones can attack
many plastics possibly damaging the sensor. Reapply antifouling
paint every 6 months or at the beginning of each boating season.
Replacement Sensor & Parts
The information needed to order a replacement sensor is printed
on the cable tag. Do not remove this tag. When ordering, specify
the part number and date. For convenient reference, record this
information at the top of page one.
Lost, broken, or worn parts should be replaced immediately.
Hull nut 02-031-3
Obtain parts from your instrument manufacturer or marine dealer.
Gemeco (USA) Tel: [phone]
Fax: [phone]
email: [e-mail]
Airmar Europe Tel: [phone]
Fax: [phone]
email: [email protected]