Airmar M260, M265LH, M265LM User Manual

INSTALLATION INSTRUCTIONSOWNER’S GUIDE &

In-Hull, 1kW

Transducer

Models: M260, M265LH, M265LM

U.S. Patent No. 7,369,458. UK Patent No. 2 414 077. U.S. Patent Pending

Follow the 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.

CAUTION: The fiberglass hull below the transducer

17-446-01 rev.05 01/12/13

must be solid. The transducer will not transmit through
coring material such as foam or balsa wood.

CAUTION: CHIRP transducer—Do not install in the
engine compartment or other hot place. The
transducer may fail if the temperature of the liquid in
the tank exceeds 60° C (140° F).

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

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

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.

Tools & Materials

Safety goggles
Dust mask
Rope
Detergent (some installations)
Weak solvent (such as alcohol)
Disk sander (some installations)
Thin sealable plastic bag (some installations)
Cable ties (some installations)
Water-based lubricant (such as K-Y
Carpenter’s level
Pencil
Saw
Scissors
Sand paper: 80 grit
Bonding material (see www.airmar.com for additional brands):

Fiberglass resin: Bondo 401

West Marine #1937762)

or Marine-Tex epoxy putty (14 oz. pack)
or 3M™ Marine Adhesive/ Sealant 5200

Propylene glycol (non-toxic anti-freeze/coolant)
Grommet(s) (some installations)
Torque wrench with Allen-wrench adaptor (recommended)

®

jelly) (some installations)

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

Part No._________________Date___________Frequency________kHz

Allen
wrench

socket head

cap screw (4)

lock washer (4)

flat washer (4)

Figure 1. M260

upper section of tank

lower section of tank

Applications

• Fiberglass hulls only

• Recommended for high-speed boats

• Accommodates a deadrise angle up to 30° with the longest side
of the tank installed parallel to the centerline (keel) of the hull.

Mounting Location

About Fiberglass Hulls

Since the hull absorbs acoustic energy, transmitting through the
hull reduces the transducer’s performance. Fiberglass hulls are
often cored in places for added strength or to reduce weight. These
cored areas contain balsa wood or structural foam which are poor
sound conductors. Do not locate the transducer over coring.

Choose a Location

• Where the fiberglass is solid (no air bubbles are trapped in the
fiberglass resin) and where no coring, flotation material, or dead
air space is sandwiched between the inside skin and outer skin
of the hull.

• Where the hull below 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).
Do not mount the transducer near water intake or discharge
openings; or behind strakes, fittings, or hull irregularities.

• 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 the deadrise angle of the hull does not exceed 30°.

• Where there is space inside the vessel for the size of the tank
and removing the transducer.

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

displacement hull

pressure waves

Testing the Location

While the boat is at the same site (depth of water), test the
transducer inside the hull at the mounting location. Use one of the
test methods below:

150- 300mm
(6-12")

planing hulls

outboard and I/O

Figure 2.

stepped hull

Best location for the transducer

Copyright © 2006 Airmar Technolog y Corp.

inboard

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.

Testing the Selected Mounting Location

Establishing a Performance Baseline

The results of this test are used as a basis of comparison to
determine the best in-hull location for the transducer.

1. Take the boat to the maximum depth in which you will be
operating the echosounder. If deep water is not available, find a
location with at least 30m (100').

2. Connect the transducer to the echosounder.

3. Tie a rope securely around the handle of the transducer (see
Figure 3). Lower it over the side of the boat until the active face
is fully submerged and parallel to the water surface.

4. Observe the echosounder’s performance and the depth reading.

A.If the transducer will be located near the stern and the boat has

a minimum deadrise angle—Clean away any build-up of dirt and/
or grease using detergent or a weak solvent such as alcohol. Place
the transducer against the hull and flood the area with bilge water
to cover the surface where they touch (see Figure 4-A).

B.For a moderate deadrise angle—If the hull surface is not

smooth, grind it with a disc sander. Place the transducer inside
a thin plastic bag. Partially fill the bag with water and close it
tightly with a cable tie. Wet the surface of the hull and press the
active face of the transducer against it through the bag (see
Figure 4-B).

C.For any location—If the hull surface is not smooth, grind it with a

disc sander. Coat the active face of the transducer with a water­based lubricant (such as K-Y

®

jelly). With a twisting motion, press
the face firmly against the hull (see Figure 4-C). After testing,
wipe away all traces of the lubricant from the transducer’s face.

Observe the echosounder’s performance and compare it to the
baseline. Look for a stable depth reading that is similar to the
baseline. Compare the thickness and intensity of the bottom trace.

If the performance is close to the baseline, this is a good mounting
location. Remember, some energy is lost transmitting through the
hull. If the test reading differs markedly from the baseline, you will
need to find another location to install the transducer.

NOTE: If there is no reading or it is erratic, the transducer may be
positioned over coring which is absorbing the acoustic energy.
Choose another location. If no other location is available, check
with the boat manufacturer to be certain coring is present.

active face

Figure 3. Establishing a performance baseline

Copyright © 2006 - 2011 Airmar Tech nology Corp.

AB C

Figure 4. Testing the transducer at the selected location

Copyright © 2006 Airmar Technology Corp.

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