Furuno PM265LH User Manual

Pocket/Keel Mount

Transducer

Models: PM260, PM265LH, PM265LM, PM270W

US Patent 7,369,458. UK 2 414 077. U.S. Patents Pending

WARNING: The transducer must be professionally installed
using accepted practices. The pocket must be strong and

INSTALLATION INSTRUCTIONSOWNER’S GUIDE &

17-566-01 rev.05 01/12/13

watertight to reduce the risk of property damage, personal
injury, and/or death.

Follow the safety precautions below for optimal
product performance and to reduce the risk of
property damage, personal injury, and/or death.

WARNING: Always wear safety goggles and a dust

mask when installing.

WARNING: Immediately check for leaks when the
boat is placed in the water. Do not leave the boat
unchecked for more than three hours. Even a small
leak may allow considerable water to accumulate.

CAUTION: CHIRP transducer—Do not install in the
engine compartment or other hot place. The
transducer may fail if it overheats.

CAUTION: CHIRP transducer—Always operate the
transducer in water. Operating in air will allow the
transducer to overheat resulting in failure.

CAUTION: The transducer must be flush with the
bottom of the hull for good performance. Dry fit the
transducer in the pocket before installing.

CAUTION: Never install a metal housing on a vessel
with a positive ground system.

CAUTION: Never mount a bronze transducer in a
metal hull, because electrolytic corrosion will occur.

CAUTION: Never pull, carry, or hold the transducer by
the cable. This may sever internal connections.

CAUTION: Never strike the transducer.

CAUTION: Never use solvents. Cleaners, fuel, sealant,

paint and other products may contain solvents that can
damage plastic parts, especially the transducer’s face.

IMPORTANT: Please read the instructions completely
before proceeding with the installation. These
instructions supersede any other instructions in your
instrument manual if they differ.

Record the information found on the cable tag for future reference.

Part No._________________Date___________Frequency________kHz

Applications

• Recommended for fiberglass hulls

• Recommended for high-speed boats

Tools & Materials

Safety goggles
Dust mask
Scissors
Masking tape
Electric drill (some installations)
Drill bits and hole saws: (some installations)

Bolt holes 11mm or 7/16"
Pilot hole for cable 8mm or 5/16"

Cable hole 35mm or 1-3/8"
Sandpaper (some installations)
Mild household detergent or weak solvent (such as alcohol)
Marine sealant (suitable for below waterline)
Torque wrench
Grommet(s) (some installations)
Cable ties
Water-based anti-fouling paint (mandatory in salt water)

NOTE: Making a fiberglass pocket in the hull requires additional
tool and materials not listed.

Installation: Pre-molded Pocket in the Hull

Metal Template Available

If the boat hull has a molded pocket to accept a pocket mounted
transducer, a metal template is available from the marine dealers
listed on page 3.

Order a PM265-Template.

Dry Fitting the Transducer

The transducer must be flush with the bottom of the hull for good
performance. Dry fit the transducer in the pocket before installing.

Bedding & Installing (see Figure 1)

CAUTION: Be sure the surfaces to be bedded are clean and dry.

1. Cut out the template on page 4.

2. Position the template within the hull pocket and tape it in place.

3. Using the appropriate drill bits and hole saw, drill the holes
through the hull at the marked locations.

4. Sand and clean 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.

5. Apply a 2mm (1/16") thick layer of marine sealant to the following
surfaces to seal the hull and hold the transducer firmly in place:

• Surface of the transducer that will contact the hull

• Cable fitting, being sure the sealant extends 6mm (1/4”) into

the hull

• Threads of the bolts

• Surface of the washers that will contact the hull

6. From outside the hull, thread the transducer cable through the
hole in the hull. Push the transducer into the mounting pocket.

7. From inside the hull, screw a nut onto each bolt. Place one
washer against each nut so that the side with the sealant will be
against the hull when installed. Then screw each bolt into a
threaded hole in the transducer. Tighten the bolts using a
torque wrench with a force not exceeding 6N-m (5ft.-lb.).

8. Lightly tighten the nuts against the hull using a torque wrench
with a force not exceeding 3.5N-m (3ft.-lb.).

9. Remove any excess marine sealant on the outside of the hull to
ensure smooth water flow under the transducer.

bolt (2)

nut &

washer (2)

hull

cable fitting

transducer

marine sealant

marine
sealant

Figure 1. Installing in a pre-molded hull pocket

Copyright © 2012 Airmar Technology Corp.

Installing the Bolts in the Transducer

Screw a nut onto each bolt. Place one washer against each nut.
Screw the two bolts with the nuts and washers in place into the
threaded holes in the transducer. Tighten the bolts using a torque
wrench with a force not exceeding 6 N-m (5ft.-lb.).

Fiberglassing the Transducer

The transducer must be professionally installed using accepted
practices. The pocket must be strong and watertight to reduce the
risk of property damage, personal injury, and/or death. The
transducer must be flush with the bottom of the hull for good
performance. Use the template on page 4 to cut the hole in the hull.

Tightening the Nuts

After the transducer has been fiberglassed to the hull, lightly
tighten the nuts using a torque wrench with a force not exceeding

3.5N-m (3ft.-lb.).

Installation: Fiberglass the Transducer to Hull

Mounting Location

Guidelines

CAUTION: Do not mount 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 in line with trailer rollers or bunks that
may damage the transducer’s face.

Choose a Location:

• Where the hull is flat or nearly flat, so the transducer beam will
be aimed straight down.

• Where the transducer will be in contact with the water at all times.

• Where the water flowing under the hull is smoothest with a
minimum of bubbles and turbulence (especially at high speeds).
Where the transducer beam will not be blocked by the keel or
propeller shaft(s).

• 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.

• Where there is working space inside the vessel.

• CHIRP transducer—Mount in a cool well-ventilated area away
from the engine to avoid overheating.

Boat Types (see Figure 2)

• Displacement hull powerboats—Locate amidships near the
centerline. The starboard side of the hull where the propeller
blades are moving downward is preferred.

• Planing hull powerboats—Mount well aft, on or near the
centerline, and well inboard of the first set of lifting strakes to
ensure that the transducer will be in contact with the water at
high speeds. The starboard side of the hull where the propeller
blades are moving downward is preferred.

Outboard and I/O—Mount just forward of the engine(s).
Inboard—Mount well ahead of the propeller(s) and shaft(s).
Stepped hull—Mount just ahead of the first step.

2

Cable Routing & Connecting

CAUTION: If the transducer came with a connector, do not

remove it to ease cable routing. If the cable must be cut and
spliced, use Airmar’s splash-proof Junction Box No. 33-035 and
follow the instructions provided. Removing the water-proof
connector or cutting the cable, except when using water-tight
junction box, will void the transducer warranty.

1. Route the cable to the echosounder being careful not to tear the
cable jacket when passing it through the bulkhead(s) and other
parts of the boat. Use grommets to prevent chafing. To reduce
electrical interference, separate the transducer cable from other
electrical wiring and the engine(s). Coil any excess cable and
secure it in place with cable ties to prevent damage.

2. Refer to your echosounder owner’s manual to connect the
transducer to the instrument.

Checking for Leaks

When the boat is placed in the water, immediately check around
the transducer 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 a leak is observed, repeat the
installation procedures immediately.

displacement hull

outboard and I/O

Figure 2.

Best location for the transducer

Copyright © 2006 Airmar Technolog y Corp.

stepped hull

inboard