Standard horizon B240, S S560, B46, B45, B261 Owner Manual

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•

OWNER’S GUIDE & INSTALLATION INSTRUCTIONS

Thru - hull, Metal Stem,

Depth Transducer

Models: B45, B46, B240, B256,

B260, B261, SS505, SS560

IMPORTANT : Please read the instructions completely

before proceeding with the installation. These
instructions supersede any other instructions in your
instrument manual if they differ.

CAUTION : NEVER USE SOLVENTS

Cleaners, fuel, paint, sealants, and other products may

17-008-05 rev. 09 02/04

contain strong solvents, such as acetone, which attack
many plastics greatly reducing their strength.

Applications

Bronze housing recommended for fiberglass or wood hulls.

Caution : Never mount a bronze housing in a metal hull,

because electrolytic corrosion will occur.

Stainless steel housing compatible with all hull materials.

• Aluminum or steel hull —Use a stainless steel housing/stem
to prevent electrolytic corrosion.

Caution : Installation requires using a fairing kit to isolate the

stainless steel transducer from a metal hull.

•

Caution : Never install a metal housing on a vessel with a

positive ground system

Tools & Materials

Safety goggles
Dust mask
Electric drill
Drill bits:

Pilot hole 3mm
B45, B46, SS505 22mm
B240, B260, B261, SS560 33mm

B256 30mm
Sandpaper
Mild household detergent
File (installation in a metal hull)
Fairing ( mandatory for SS505 and SS560 )
Digital level
Band saw
Rasp
Marine sealant
Slip-joint pliers
Zip-ties
Water-based antifouling paint ( mandatory in salt water )
Installation in a cored fiberglass hull: (see page 4)

Drill bit for hull interior:

B45, B46, SS505 35mm

B240, B260, B261, SS560 42mm

B256 40mm, 41mm,

Cylinder, wax, tape, and casting epoxy

or

bubble level & protractor (installation w/ fairing)

or

hand saw (installation with a fairing)

or

power tool (installation with a fairing)

.

or

weak solvent (alcohol)

or

1/8"

or
or

or

or
or

7/8"
1-5/16"
1-3/16"

1-3/8"
1-5/8"

or

1-5/8"

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

Part No._________________Date___________Frequency________kHz

standard
fairing

B45

High-Performance

fairing

Identify Your Model

The model name is printed on the cable tag.

About Fairings

Nearly all vessels have some deadrise angle at the mounting
location. If the transducer is mounted directly to the hull, the
sound beam will be tilted off the vertical at the same angle as the
deadrise. A fairing is strongly recommended if the deadrise angle
exceeds 10 ° .

•Orients the sound beam straight down by mounting the
transducer parallel to the water surface

• Minimizes aerated water flowing over the transducer’s face by
mounting it deeper in the water

Airmar Polymer Fairing

Made of a high-impact polymer with an integrated cutting guide,
an Airmar fairing is safer and easier to cut with a band saw and
shape with hand tools than custom fairings. It can be shaped to
accommodate a deadrise angle of up to about 25 ° . (For fairing
part numbers, see “Replacement Parts” on page 4.)

A backing block is mounted inside the hull to provide a level
surface for the hull nut to seat against (see Figure 2). It is
fabricated matching the interior deadrise angle of the boat. After
cutting an Airmar fairing, use the remaining section with the
cutting guide for the backing block.

Airmar High-Performance Fairing

A high-performance fairing has a long streamlined shape for excel­lent performance above 15 kn (18MPH) (see “Parts” on page 4).

Mounting Location

Acoustic Noise

Acoustic noise is always present and these sound waves can
interfere with the operation of the transducer. Background noise
from sources such as: waves, fish, and other vessels cannot be
controlled. However, carefully selecting the transducer mounting
location can minimize the effect of vessel generated noise from
the propeller(s) and shaft(s), other machinery, and other echo­sounders. The lower the noise level, the higher the echosounder
gain setting that can be used.

1/3 aft

LWL

(Load Waterline Length)

outboard and I/O

step-hull

displacement hull

planing hulls

fin keel sailboat

pressure waves

150- 300 mm
(6-12")

inboard

AIRMAR

®

• Fin keel sailboat —Mount to the side of the centerline and
forward of the fin keel 300–600mm (1–2').

• Full keel sailboat —Locate amidships and away from the keel
at the point of minimum deadrise angle.

—

Installation

No fairing or standard fairing only

WARNING : High-performance fairing must be installed

following the Installation Instruction Supplement that comes with
the fairing. The high-performance fairing requires an anti-rotation
bolt. Failure to install the anti-rotation bolt may result in the fairing
rotating while the boat is underway. The effect may be violent
movement and loss of steering. This could result in serious injury
or death to passengers and/or damage to the boat or other
property.

Metal hull —The SS505 and SS560 must be isolated from a metal

hull. For your safety you must follow the Installation Instruction
Supplement provided with the fairing.

Cored fiberglass hull —Follow separate instructions on page 4.

No fairing —If you are installing a transducer without a fairing,

disregard all references to a fairing.

full keel sailboat

Figure 1.

Best location for the transducer

Placement

Choose a location where:

• The water flowing across the hull is smoothest with a minimum
of bubbles and turbulence (especially at high speeds).

• The transducer will be continuously immersed in water.

• There is a minimum deadrise angle.

• The transducer beam is unobstructed by keel or propeller shaft(s).

• There is adequate headroom inside the vessel for the height of
the housing and tightening the nut.

Caution : Do not mount the transducer:

Near water intake or discharge openings
Behind strakes, fittings, or hull irregularities
Behind eroding paint (an indication of turbulence)

Boat Types

• Displacement hull powerboat —Locate 1/3 aft LWL and
150–300mm (6–12") off the centerline on the side of the hull
where the propeller is moving downward.

• Planing hull powerboat —Mount well aft, near the centerline,
and
the transducer is in contact with the water at high speeds.
Mount on the side of the hull where the propeller is moving
downward.

Outboard and I/O —Mount just forward and to the side of the

engine(s).

Inboard —Mount well ahead of the propeller(s) and shaft(s).
Step-hull —Mount just ahead of the first step.
Boat capable of speeds above 25kn (29MPH)—Review

transducer location and operating results of similar boats before
proceeding.

2

(see Figure 1)

well inboard of the first set of lifting strakes

to insure that

Hole Drilling

Warning : Always wear safety goggles and a dust mask.

1. Drill a 3mm or 1/8" pilot hole perpendicular to the waterline from
inside the hull (see Figure 2). If there is a rib, strut or other hull
irregularity near the selected mounting location, drill from the
outside.

2. Using the appropriate drill bit, cut a hole from outside the hull.

Be sure

to the water surface.

3. Sand and clean the area around the hole, inside and outside, to
ensure that the marine sealant will adhere properly to the hull. If
there is any petroleum residue inside the hull, remove it with
either a mild household detergent or a weak solvent (alcohol)
before sanding.

Metal hull —Remove all burrs with a file and sandpaper.

to hold the drill plumb, so the hole will be perpendicular

cable

stem

hull nut

backing block

fairing thickness

6–12mm (1/4–1/2")

standard fairing

Figure 2. Bedding and installing

(B45 with std. fairing shown)

Aft View

AIRMAR

hull

slope of hull

deadrise
angle

parallel to
waterline

marine
sealant

®