4
Installation in a Cored Fiberglass Hull
The core (wood or foam) must be cut and sealed carefully. The core must
be protected from water seepage, and the hull must be reinforced to
prevent it from crushing under the hull nut allowing the housing to become
loose.
CAUTION
: Completely seal the hull to prevent water seepage into
the core.
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. (If the hole is drilled in the wrong location, drill a second hole
in a better location. Apply masking tape to the outside of the hull over the
incorrect hole and fill it with epoxy.)
2. Using a 51mm or 2" hole saw, cut the hole from outside the hull through
the
outer
skin only
(see
Figure 6).
3. From inside the hull using a 60mm or 2-3/8" hole saw, cut through the
inner
skin and most of the core. The core material can be very soft.
Apply only light pressure to the hole saw after cutting through the inner
skin to avoid accidentally cutting the
outer
skin.
4. Remove the plug of core material so the
inside
of the outer skin and the
inner core of the hull are fully exposed. Sand and clean the inner skin,
core, and the outer skin around the hole.
5. If you are skilled with fiberglass, saturate a layer of fiberglass cloth with
a suitable resin and lay it inside the hole to seal and strengthen the
core. Add layers until the hole is the correct diameter.
Alternatively, a hollow or solid cylinder of the correct diameter can be
coated with wax and taped in place. Fill the gap between the cylinder and
hull with casting epoxy. After the epoxy has set, remove the cylinder.
6. 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 mild household
detergent or a weak solvent (alcohol) before sanding.
7. Proceed with “Bedding” on page 2.
Operation & Maintenance
How the Valve Works
The valve is not a watertight seal!
The transducer incorporates a self-
closing valve which minimizes the flow of water into the boat when the
insert is removed. The curved flap valve is activated by both a spring and
water pressure. Water pushes the flap valve upward to block the opening,
so there is no gush of water into the boat. Always use the insert or the
blanking plug secured with the safety wire for a watertight seal.
Using the Blanking Plug
To protect the insert, use the blanking plug:
• When the boat will be kept in salt water for more than a week.
• When the boat will be removed from the water.
• When aquatic growth buildup on the insert is suspected due to
inaccurate readings from the instrument.
1. The O-rings must be intact and well lubricated to make a watertight seal.
On the blanking plug, inspect the O-rings (replace if necessary) and
lubricate them with the silicone lubricant supplied or petroleum jelly
(Vaseline
®
) (see Figure 7).
2. Remove the insert from the housing by removing the safety wire and
unscrewing the cap nut (see Figure 5). This will jack out
the insert. Grasp the insert and remove it with a slow pulling motion.
Slide the blanking plug into the housing. Be sure the blanking plug is
fully inserted. Screw the cap nut several turns until the threads are
engaged. Continue to tighten the cap nut completely.
Hand tighten
only. Do not over tighten.
NOTE
: In the very unlikely event that the valve breaks, replace the
housing the next time the boat is hauled.
3. Reattach the safety wire to prevent the blanking plug from backing out
in the unlikely event that the cap nut fails or is screwed on incorrectly.
Cleaning the Insert
Aquatic growth can accumulate rapidly on the depth transducer’s face
reducing performance within weeks. Clean the insert with a Scotch-Brite®
scour pad and mild household detergent, being careful to avoid making
scratches. If fouling is severe, lightly wet sand it with fine grade wet/dry
paper.
Winterizing
After the boat has been hauled for winter storage, remove the blanking plug to
let the water drain away before reinserting it. This will prevent any water from
freezing around the blanking plug and possibly cracking it.
Replacement Transducer & Parts
The information needed to order a replacement Airmar transducer is
printed on the cable tag. Do not remove this tag. When ordering, specify
the part number, date, and frequency in kHz. For convenient reference,
record this information on the top of page one.
Lost, broken, or worn parts should be replaced immediately. If you have
purchased a plastic housing and have a wood hull or desire greater
strength, purchase an Airmar metal housing.
Obtain parts from your instrument manufacturer or marine dealer.
Gemeco
Tel: 803.693.0777
(USA)
Fax:
803.693.0477
email:
Airmar EMEA
Tel:
+33.(0)2.23.52.06.48
(Europe, Middle East, Africa) Fax:
+33.(0)2.23.52.06.49
email:
Blanking
Plug
Hull Nut
Washer
Housing with Valve,
Hull Nut, and Washer
33-538-01
04-004 (plastic)
02-030 (bronze)
02-530-02 (stainless steel)
09-452
33-510-01 (plastic, P617V)
33-588-01 (bronze, B617V)
33-617-01 (stainless steel, SS617V)
Copyright © 2006 - 2014 Airmar Technology Corp. All rights reserved.
Figure 7. Replacing the O-rings
blanking
insert
yellow
O-ring
small
black
plug
O-ring(s)
Copyright © 2005 Airmar Technology Corp.
Figure 6. Preparing a cored fiberglass hull
inner skin
core
outer skin
solid or hollow cylinder
pour in
casting
epoxy
9-12 mm
(3/8-1/2")
larger than the
hole through the
hull’s outer skin
hull thickness
Copyright © 2004 Airmar Technology Corp.
35 Meadowbrook Drive, Milford, New Hampshire 03055-4613, USA
•
www.airmar.com