Airmar M42 - Manual

17-011 re
v.
05
10/05
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.
Sealcast ™ and Cast Resin Transducers
Models: M42, M155, M163, M172, M177, R155
Mounting Location
Carefully study the hull to determine the best mounting location.
• Away from the propeller(s) and shaft(s), other machinery, and
other echosounders to minimize the effect of noise on the
echosounder display. The lower the noise level, the higher the
gain setting that can be used.
• On the side of the hull where the propeller(s) blades are moving
downward. The upward motion of blades generates pressure
waves and pushes bubbles up against the hull. By mounting on
the downward side, the hull shades the transducer from this
effect (see Figure 1).
• Where the transducer beam will be unobstructed by the keel or
propeller shaft(s).
• Where there is a minimum deadrise angle.
• Where there is adequate headroom inside the vessel for the
height of the stuffing tube and tightening the nuts.
• Locate the transducer about 1/3 aft LWL. Generally, this
provides the best compromise between obtaining aeration-free
water away from the bow and minimizing propeller noise (see
Figure 2).
Caution : Do not mount in an area of turbulence or bubbles:
Near water intake or discharge openings,
Behind strakes, fittings, or hull irregularities.
Stuffing Tube
Choosing the Stuffing Tube
Warning: A stuffing tube is required for all installations.
Caution : The stuffing tube must be compatible with the hull material
The stuffing tube seals the hull forming a water-tight conduit for
the cable. Choose a stuffing tube based on the hull material and
diameter of the transducer cable. Airmar stuffing tubes are
available from your marine dealer (see table below).
Fiberglass hull —The stuffing tube must be installed in solid
fiberglass, not in coring.
Aluminum hull —Use a stainless steel stuffing tube. Never use a
bronze stuffing tube as electrolytic corrosion will occur.
Stuffing Tube
Material
Hull Material Cable Diameter
Hull Hole
Diameter Airmar
Part No.
bronze
fiberglass
wood
up to 0.47” D 44mm (1-3/4") 33-511-01
stainless steel
fiberglass, wood
steel, aluminum a
a. Requires the tube to be isolated from the hull with non-electrically conductive spacers.
Installing the Stuffing Tube
After determining the best mounting location, install the stuffing tube.
Follow the installation instructions that came with the stuffing tube.
up to 0.47” D 26mm (1") 33-819
steel weld to steel hull up to 0.5” D 38mm (1-1/2") 33-818
Record the information found on the cable tag for future reference.
Part No._________________Date___________Frequency________kHz
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 INSTRUCTIONS OWNER’S GUIDE &
Figure 1. Mounting location and deadrise angle
fairing
aeration, cavitation, and turbulence
pressure waves
Transom View
deadrise angle
slope of hull
parallel to waterline
Figure 2. Mounting location on displacement hull
1/3 aft
(Load Waterline Length)
LWL
AIRMAR ® AIRMAR ®
M155
- corrects for the deadrise angle
of the hull, so the transducer
beams shoots straight down
- mounts the transducer deeper
in the water for clean flow
over the transducer’s face