Airmar R109LH Technical Document

D-17-335-01-rev. 13 17-335-01-rev.13 12/14/22
Thru-Hull External Mount: 2-3kWwith Temp. Sensor
Depth Transducer
Chirp Models: R109LH, R109LM, R109LHW, R409LWM,
R509LH, R509LM, R509LHW
Patent http://www.airmar.com/patent.html
IMPORTANT: Please read the instructions completely
before proceeding with the installation. These instructions
supersede any other instructions in your instrument manual
if they differ.
Applications
• Recommended for all hull materials
• Not recommended for hulls less than 9m (30') long
• Not recommended for stepped hulls. Mount an in-hull transducer.
• Accommodates a deadrise angle up to 22
Pretest
Connect the temperature function to the instrument and check for
the approximate air temperature. If there is no reading or it is
inaccurate, check the connections and test again. If there is still a
problem, return the product to your place of purchase.
Tools & Materials
Safety glasses
Dust mask
Ear protection
Angle finder
Band saw (blade must be very sharp)
Rasp or power tool
Electric drill
Drill bits and hole saws:
pilot hole Ø 3mm or 1/8"
fiberglass, wood or steel hull Ø 14mm or 9/16"
aluminum hull Ø 15mm or 9/16"
Permanent marker
Mild household detergent or weak solvent (such as alcohol)
Sandpaper
File (installation in a metal hull)
Marine sealant (suitable for below waterline)
Wrenches
Torque wrench
Grommet(s) (some installations)
Cable ties
Water-based anti-fouling coating (mandatory in salt water)
Follow the precautions below for optimal
product performance and to reduce the risk of
property damage, personal injury and/or death.
WARNING: Boats capable of speeds above 25kn
(29MPH)—You must follow these instructions for a safe
installation. For boats exceeding 35 kn (40 MPH) or when the
instructions cannot be met, mount an in-hull transducer. At
high speeds, the fairing and/or transducer may break away
from the boat.
WARNING: A stuffing tube is required. The stuffing tube seals
the hull forming a water-tight conduit for the cable.
WARNING: Always wear safety glasses, a dust mask and ear
protection when installing.
WARNING: The fairing must be installed parallel to the keel to
ensure proper boat handling and water flow under the
transducer.
WARNING: Immediately check for leaks when the boat is
placed in the water. Do not leave the boat in the water
unchecked for more than three hours. Even a small leak may
allow considerable water to accumulate.
WARNING: Fiberglass hull—The transducer and stuffing
tube must be installed in solid fiberglass, not in coring.
CAUTION: Aluminum hull—The stainless steel hardware
must be isolated from an aluminum hull to prevent electrolytic
corrosion.
CAUTION: Steel hull—Follow generally accepted installation
practices.
CAUTION: Never install a metal fitting on a vessel with a
positive ground system.
CAUTION: Externally mount the transducer only. The active
face and sides of the transducer must be immersed in water to
cool the unit.
CAUTION: Chirp transducer—Always operate the
transducer in water. Operating in air will allow the transducer to
overheat, resulting in failure.
CAUTION: Never pull, carry or hold the transducer by its cable.
This may sever internal connections.
CAUTION: Never strike the transducer.
CAUTION: Tighten the nylon locking nuts with a torque wrench
using a force not exceeding 27N-m (20ft.-lb.). Do not over
tighten. It may crack the transducer and/or crush the fairing.
CAUTION: Do not spray paint. Spraying creates tiny bubbles
in the paint which will adversely affect the transducer’s
performance.
CAUTION: Never power sand or pressure wash the sensor. It
may weaken the structure or damage the internal parts.
CAUTION: Never use solvents. Cleaner, fuel, sealant, paint
and other products may contain solvents that can damage
plastic parts, especially the transducer’s face.
OWNER’S GUIDE & INSTALLATION INSTRUCTIONS
Record the information found on the cable tag for future reference.
Part No:____________________Serial No:________________________
Date_______________Frequency____________________________kHz

2
Figure 5. Fairing Figure 4. Fairing
NOTE : After the fairing is cut,
the section with the cutting guide
becomes the backing block.
20mm
(3/4")
cutting
guide
cavity for
22
° max
cutting
guide
min.
stuffing
tube
bottom view aft view
Copyright © 2007 - 2011 Airmar Technology Corp. Copyright © 2005 Airmar Technology Corp.
Figure 3. Cutting the fairing
cutting
guide
band saw
table
deadrise
angle
fence
Copyright © 2005 Airmar Technology Corp.
location
of stuffing
tube
Bow
▲
Mounting Location
Guidelines
CAUTION: Do not mount the sensor in line with or near water
intake or discharge openings or behind strakes, fittings or hull
irregularities that will disturb the water flow.
CAUTION: Do not mount the sensor where the boat may be
supported during trailering, launching, hauling or storage to avoid
damaging the transducer’s face.
• The water flowing under the hull must be smooth with a
minimum of bubbles and turbulence (especially at high speeds).
• The transducer must be continuously immersed in water even
when the boat is rolling, pitching or up on a plane at high speed.
• The transducer beam must be unobstructed by the keel or
propeller shaft(s).
• Choose a location away from interference caused by power and
radiation sources such as: the propeller(s) and shaft(s), other
machinery, other echosounders and other cables. The lower the
noise level, the higher the echosounder gain setting that can be
used.
• Choose a location with a minimal deadrise angle, not to
exceed 22.
• Choose an accessible spot inside the vessel with adequate space
for the height of the stuffing tube and tightening the nuts.
Hull Types
•Displacement hull powerboat—Locate about 1/3 of the way
along the LWL and 200 to 600mm (8–24") off the centerline
(Figure 1). The side of the hull where the propeller blades are
moving downward is preferred.
•Planing hull powerboat— (Figure 2)
• Mount within the aft 1/3 of the hull, as far back as possible.
Outboard and I/O—Mount just forward of the engine(s).
Inboard—Mount ahead of the propeller(s) and shaft(s).
• Mount on or as close to the centerline as possible, and well
inboard of the first set of lifting strakes to ensure that the
transducer is in contact with the water at high speeds.
• Mounting on the side of the hull where the propeller blades
are moving downward is preferred.
Stuffing Tube
After determining the best mounting location for the transducer,
install the stuffing tube. Follow the installation instructions
packaged with the stuffing tube.
Fairing: Cutting, Bedding & Installing
Cutting the Fairing
CAUTION: Shape the fairing to the hull as precisely as possible. If
there are gaps between the fairing and the hull near the ends, cut
a new fairing. Over tightening the rods to minimize gaps may
crack the transducer and/or crush the fairing.
1. Measure the deadrise angle of the hull at the stuffing tube using
an angle finder (Figure 1).
2. Tilt the band saw table to the measured angle and secure the
cutting fence (Figure 3). Do not exceed 22.
3. Place the fairing on the table so the cutting guide rests against
the fence (Figures 3 and 4). Note, the fairing is symmetrical.
4. Adjust the fence so the fairing will be cut in about two equal parts.
The section that will become the fairing must be a minimum of
20mm (3/4") at its thinnest dimension (Figure 5).
5. Recheck steps 1 through 4; then cut the fairing.
6. Check the fit by placing the fairing against the hull. Be sure the
fairing is parallel to the centerline of the boat (keel), and the
stuffing tube is about 2/3 of the way back in the cavity (Figure
4). Hold the fairing on the ends and try to rock it back and forth.
Shape the fairing to the hull as precisely as possible with a rasp
or power tool until it no longer rocks.
deadrise
slope of hull
parallel to
Figure 1. Transducer location on displacement hull
pressure waves
1/3
(8 – 24")
200-600mm
LWL
(Load Waterline Length)
angle
waterline
Copyright © 2005 Airmar Technology Corp.
Figure 2. Transducer location on planing hull
inboard
outboard and I/O
Copyright © 2005, 2009 Airmar Technology Corp.
NOTE: Mount within the
aft 1/3 of the hull, as far
back as possible.

Figure 7. Threaded rod
102mm
color this
section of
rod with
permanent
marker
(4")
Copyright © 2007 - 2015 Airmar Technology Corp.
sleeve for
installation
in aluminum
hull only
3
Figure 6. Bedding and installing the fairing and backing block (non-metal hull shown)
fairing
backing
threaded
hull
marine
sealant on
marine
sealant on
washers (2),
backing block,
fairing,
recess
rod (2)
block
(uncolored)
Copyright © 2007 Airmar Technology Corp.
stuffing
tube
70mm
(2-3/4") metal nut
& washer
A
Bow
►
threaded
metal nut (4)
nylon locking nut (2)
marine sealant on
washer (2)
and washer (2)
metal nut (2)
transducer
hull
foam plug (2)
Figure 8. Bedding and installing the transducer (non-metal hull shown)
backing block
washer (2)
stuffing
cable
fairing
rounded bottom
temperature
tube
sensor
rod (2)
transducer that contacts
fairing and recess
Copyright © 2007 Airmar Technology Corp.
marine sealant
flush with hull
rods (2)
7. The remaining section of the fairing with the cutting guide will
be used as the backing block inside the hull. It will provide a
level surface for tightening the nuts on the threaded rods.
Dry Fitting the Fairing
1. To locate the hole for the forward threaded rod (nearest the bow),
measure the distance between the cable exit and the forward hole
in the transducer, center to center. (The rounded bottom is forward
and the temperature sensor is aft.) Being sure the fairing will be
parallel to the centerline of the boat (keel), measure this
distance A on hull and mark the hole (Figure 6).
2. Drill a pilot hole at the marked location. Using the appropriate
size drill bit, drill the hole through the hull for one threaded rod.
Do not drill the second hole at this time.
3. Prepare the threaded rods (Figure 7). Using a permanent marker,
draw a line on each threaded rod 102mm (4") from the end and
color this section. (The colored section will be used to fasten the
transducer to the fairing.) Screw a nut onto the colored section of
each threaded rod above the 102mm (4") line drawn.
4. Place the fairing against the hull. Push the uncolored end of the
threaded rod through the fairing and the hull until the nut rests
inside the recess in the fairing (Figure 6). With a person stationed
inside the vessel, slide the backing block onto the rod.
Temporarily secure the rod with a stainless steel washer and nut.
5. Align the fairing parallel to the centerline of the boat (keel).
Using the aft hole in the fairing as a guide, drill a pilot hole.
Then drill the hole using the appropriate size drill bit.
6. Remove the fairing from the hull. Clean and sand the area
around the holes, inside and outside, to ensure that the marine
sealant will adhere properly. Remove any petroleum residue with
a mild household detergent or a weak solvent such as alcohol.
Metal hull—Remove all burrs with a file and sandpaper.
Bedding & Installing the Fairing
CAUTION: Be sure the surfaces to be bedded are clean and dry.
1. If there is any residue on the fairing and transducer, remove it
with a mild household detergent to ensure the marine sealant
will adhere properly.
2. Apply a 2mm (1/16") thick layer of marine sealant (Figure 6):
• To the surface of the backing block that will contact the hull
interior
• To the surface of the fairing that will contact the hull
• To the recesses in the fairing for the washers and nuts
• To the threaded rods
• To the surface of the washers that will contact the backing block
NOTE: Be sure the rods have marine sealant on the threads under
the nuts. Back each nut off 13mm (1/2") and apply sealant to the
threads. Then return each nut to the marked location on the rod.
3. Slide a washer along the uncolored section of each threaded
rod until it rests against the nut (Figure 7).
Aluminum hull—The stainless steel rods must be isolated from
an aluminum hull to prevent electrolytic corrosion. Cut the
isolation sleeve 70mm (2-3/4") long. Slide the isolation sleeve
over the uncolored section of each bedded rod as far down as
possible. Apply a 2mm (1/16") thick layer of the marine sealant
to the outside of the sleeving.
isolation
Bow
►

4Copyright © 2005 - 2022 Airmar Technology Corp. All rights reserved.
4. Push the uncolored section of each threaded rod through the
fairing, the hull and the backing block until the washer rests inside
the recess in the fairing (Figure 6). With a person stationed inside
the vessel, secure each rod with a washer (bedded side against
the backing block) and double stainless steel nuts. Use a wrench
to hold the lower nut while tightening the top nut against it.
Aluminum hull—The top of the isolation sleeve must be below
the top of the backing block to prevent the sleeving from
interfering with tightening the nuts.
Wood hull—Allow the wood to swell before tightening the nuts.
Transducer: Bedding & Installing
1. Apply a 2mm (1/16") thick layer of marine sealant to the surface
of the transducer that will contact the fairing including the
recesses for the washers and nuts (Figure 8).
2. Thread the transducer cable through the stuffing tube.
3. Slide the transducer onto the threaded rods, being sure the
rounded bottom is facing forward toward the bow and the
temperature sensor is aft. Seat the transducer firmly within the
recess in the fairing. Secure the transducer in place by applying
a washer and a nylon locking nut to each threaded rod.
Tighten each nut with a torque wrench using a force not
exceeding 12N-m (10ft.-lb.). Then tighten each nut again using
a force not exceeding 27N-m (20ft.-lb.). Do not over tighten as it
may crack the transducer and/or crush the fairing. Be sure the
rods extend a minimum of 3 threads beyond the nut after
being tightened.
4. Plug the mounting holes to minimize turbulence on the surface
of the transducer. Be sure there is marine sealant on the
exposed threads of the rods. Cut the white foam plugs to length
so that when installed, each plug is recessed 5mm (3/16")
below the surface of the transducer. Push the foam plugs into
the holes. Use marine sealant to fill the remaining recess flush
with the transducer’s surface.
5. Remove excess marine sealant on the outside of the hull to
ensure smooth water flow under the transducer.
Sealing & Routing the Cable
To form a watertight seal inside the stuffing tube, follow the
installation instructions that came with your stuffing tube. The
completed installation will look like Figure 9.
1. Route the cable to the echosounder, being careful not to tear the
cable jacket when passing it through the bulkhead and other
parts of the boat. Use grommet(s) to prevent chafing. To reduce
electrical interference, separate the transducer cable from other
electrical wiring and the engine. Coil any excess cable and
secure it in place with cable ties to prevent damage.
2. Refer to your echosounder owners manual to connect the cable
to the instrument.
Checking for Leaks
When the boat is placed in the water, immediately check around
the threaded rods and the stuffing tube for leaks. Note that very
small leaks may not be readily observed. It is best not to leave the
boat in the water unattended for more than 3 hours before
rechecking. If there is a small leak, there may be considerable
bilge water accumulation after 24 hours. If a leak is observed,
repeat the bedding and installing procedures beginning on page 3
immediately.
Maintenance, Repair & Replacement
Antifouling Coating
Surfaces exposed to saltwater 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.
Cleaning
Aquatic growth can accumulate rapidly on the transducer’s
surface reducing its performance within weeks. Clean it using a
Scotch-Brite® scour pad and mild household detergent, being
careful to avoid making scratches. In severe cases, lightly wet
sand the surface with fine grade wet/dry paper.
Replacement Transducer & Parts
The information needed to order a replacement transducer is printed
on the cable tag. Do not remove this tag. When ordering, specify the
part number, serial number, date and frequency in kHz. For
convenient reference, record this information on the top of page 1.
Lost, broken and worn parts should be replaced immediately.
Obtain parts from your instrument manufacturer or marine dealer.
Gemeco USA
Tel: [phone]
Email: [email protected]
Airmar EMEA Europe, Middle East, Africa
Tel: [phone]
Email: [e-mail]
cable
backing block
fairing
hull
stuffing tube
transducer
Figure 9. Completed installation (non-metal hull shown)
Copyright © 2005 Airmar Technology Corp.
aft view
35 Meadowbrook Drive, Milford, New Hampshire 03055-4613, USA
www.airmar.com