Airmar ST600 - Manual (Page 3)

Cored fiberglass hull—Do not over tighten, crushing the hull.
Wood hull—Allow the wood to swell before tightening the nut.
4. Remove any excess sealant on the outside of the hull to ensure
smooth water flow under the paddlewheel.
5. After the sealant cures, inspect the o-rings on the paddlewheel
insert (replace if necessary) and lubricate them with the silicone
lubricant supplied. The o-rings must be intact and well
lubricated to make a watertight seal.
6. Slide the paddlewheel insert into the housing with the arrow on
the top pointing forward toward the bow. Seat it into place with a
pushing twisting motion until the key fits into the notch. The
arrow on the top of the insert, the notch, and the arrow on the
flange of the housing will all be aligned. Be careful not to rotate
the housing and disturb the sealant. Screw the cap nut in place
and hand-tighten only. Do not over tighten (see Figure 3).
7. Attach the safety wire to prevent the insert from backing out in the
unlikely event that the cap nut fails or is screwed on incorrectly.
Plastic housing—Attach the safety wire to one eye in the hull
nut. Keeping the wire taut throughout, lead the wire in a
counterclockwise direction and thread it through one eye in the
cap nut, the pull ring, the second eye in the cap nut, and the
second eye in the hull nut. Twist the wire securely to itself.
Metal housing—Wrap one end of the safety wire tightly around
the housing and twist it together with the long end. Keeping the
wire taut throughout, lead the wire straight up and through the
eye in the cap nut. Loop the wire through the pull ring and twist
it securely to itself.
Cable Routing & Connecting
CAUTION: If your sensor came with a connector, do not remove it
to ease cable routing. If the cable must be cut and spliced, use
Airmar’s splash-proof Junction Box 33-035 and follow the
instructions provided. Removing the waterproof connector or
cutting the cable, except when using a watertight junction box, will
void the sensor’s warranty.
1. Route the cable to the instrument being careful not to tear the
cable jacket when passing it through the bulkhead and other
parts of the boat. Use grommets to prevent chafing. To reduce
electrical interference, separate the sensor cable from other
electrical wiring and the engine. Coil any excess cable and
secure it in place using cable ties to prevent damage.
2. Refer to the instrument owner’s manual to connect the sensor
to the instrument.
Checking for Leaks
When the boat is placed in the water, immediately check around
the thru-hull sensor for leaks. Note that very small leaks may not
be readily observed. Do not leave the boat in the water
unchecked for more than 3 hours. If there is a small leak, there
may be considerable bilge water accumulation after 24 hours. If a
leak is observed, repeat “Bedding” and “Installing” immediately
(see page 2).
Installation in a Cored Fiberglass Hull
CAUTION: Completely seal the hull to prevent water seepage into the core.
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.
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 the 51mm or 2" hole saw, cut the hole from outside the hull
through the outer skin only (see Figure 4).
3. From inside the hull, use the 60mm or 2-3/8" hole saw to 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. Clean and sand 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 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 the “Bedding” and “Installing” on page 2.
Operation, Maintenance, Repair & Parts
How the Valve Works
The valve is not a watertight seal! The sensor incorporates a
self-closing valve which minimizes the flow of water into the boat
when the paddlewheel 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 paddlewheel insert or the
blanking plug secured with the safety wire for a watertight seal.
Using the Blanking Plug
To protect the paddlewheel, use the blanking plug when:
• The boat will be kept in salt water for more than a week.
• The boat will be removed from the water.
• Aquatic growth build-up on the paddlewheel is suspected due
to inaccurate readings from the instrument.
1. On the blanking plug, inspect the o-rings (replace if necessary)
and lubricate them with the silicone lubricant supplied or
petroleum jelly (Vaseline®). The o-rings must be intact and well
lubricated to make a watertight seal.
2. Remove the paddlewheel insert from the housing by removing
the safety wire and unscrewing the cap nut (see Figure 3).
3. Grasp the pull ring and remove the paddlewheel insert with a
slow pulling motion.
NOTE: In the unlikely event that the paddlewheel insert cannot
be removed, see “Servicing the Valve Assembly” on page 4.
4. Slide the blanking plug into the housing with the arrow on the
top pointing forward toward the bow. Seat it into place with a
Figure 4. 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
3
Copyright © 2001 Airmar Technology Corp.