•
Fin keel sailboats
—Mount on or near the centerline and
forward of the fin keel 300–600mm (1–2').
•
Full keel sailboats
—Mount amidships and away from the keel
at the point of minimum deadrise angle.
•
Displacement hull powerboats
—Locate amidships near the
centerline.
•
Planing hull powerboats
—Mount well aft to insure that the
sensor is in contact with the water at high speeds.
Anti-fouling Paint
Aquatic growth can accumulate rapidly on the sensor’s surface
reducing performance within weeks. Surfaces exposed to salt
water
must
be coated with anti-fouling paint.
Use water-based
anti-fouling paint only
. Never use ketone-based paint, since
ketones can attack many types of plastic possibly damaging the
sensor.
It is easier to apply anti-fouling paint before installing the sensor,
but allow sufficient drying time. Reapply paint every 6 months or
at the beginning of each boating season. Paint the following
surfaces (Figure 1):
• Outside wall of the paddlewheel insert below the lower O-ring
• Paddlewheel cavity
• Paddlewheel
• Bore of the housing up 30mm (1-1/4")
• Exterior flange of the housing
• Blanking plug below the lower O-ring including the exposed end
Installation
Hole Drilling
Cored fiberglass hull
—Follow separate instructions on page 3.
1. Drill a 3mm or 1/8" pilot hole from inside the hull. If there is a rib,
strut, or other hull irregularity near the selected mounting
location, drill from the outside.
2. Using a 51mm or 2" hole saw, cut a hole perpendicular to the
hull from outside the boat.
P398
—Use a countersink tool to make a “seat” in the hull.
3. Sand and clean the area around the hole, inside and outside, to
ensure that the sealant will adhere properly to the hull. If there is
any petroleum residue inside the hull, remove it with either mild
household detergent or a weak solvent (alcohol) before sanding.
Metal hull
—Remove all burrs with a file and sandpaper.
Bedding
CAUTION
: Be sure the surfaces to be bedded are clean and dry.
Apply a 2mm (1/16") thick layer of marine sealant around the
flange of the housing that contacts the hull and up the sidewall of
the housing (Figure 2). The sealant must extend 6mm (1/4")
higher than the combined thickness of the hull, any washer(s),
and the hull nut. This will ensure there is sealant in the threads to
seal the hull and hold the hull nut securely in place.
Installing
CAUTION
: The arrow on the flange of the housing must point
forward toward the bow for the paddlewheel insert to align properly.
1. From outside the hull, push the housing into the mounting hole
using a twisting motion to squeeze out excess sealant.
Align the
arrow on the flange of the housing pointing forward toward the
bow
(Figure 2). If the sensor is not installed on the centerline of
the boat, angle the housing slightly toward the centerline to align
it with the water flow.
2. From inside the hull, slide any washer(s) onto the housing.
NOTE
: Some installations do not have a washer.
Aluminum hull less than 6mm
(
1/4"
)
thick
—Use an additional
rubbery, plastic, or fiberglass washer. Never use wood, since it
will swell, possibly fracturing the plastic housing. Never use
bronze, since electrolytic corrosion will occur.
2
Figure 2. Bedding and installing (
low profile shown)
hull
safety
cap nut
hull nut
sealant on flange
paddlewheel
arrow
and side wall
washer
wire
large
O-ring
detail
key
small
O-ring
Figure 3. Paddlewheel insert (
no paddlewheel shown)
notch
(some
installations)
insert
housing
Copyright © 2000 Airmar Technology Corp.
Copyright © 2000 Airmar Technology Corp.
Figure 1. Anti-fouling paint
(low profile shown)
paddlewheel
cavity
paddlewheel
bore of housing
exterior flange of housing
outside wall below
lower O-ring
paddlewheel
up 30mm (1-1/4")
insert
housing
Copyright © 2004 Airmar Technology Corp.
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