Airmar DST800 Retractable with Valve—TRIDUCER® Multisensor - Manual (Page 3)

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 the appropriate size hole saw, cut a hole perpendicular to the hull
from outside 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. The
sealant must extend 6mm (1/4") higher than the combined thickness of
the hull, the washer(s), and the hull nut (see Figure 3). This will ensure
there is sealant in the threads to seal the hull and to hold the hull nut
securely in place.
Stainless steel housing in a metal hull—A stainless steel housing must
be isolated from a metal hull to prevent electrolytic corrosion. Slide the
isolation bushing onto the housing. Apply additional sealant to the
surfaces of the bushing that will contact the hull, filling any cavities in and
around the bushing.
Installing
NOTE: Disregard any arrow on the housing; it is not used.
1. From outside the hull, push the housing into the mounting hole using a
twisting motion to squeeze out excess sealant (see Figure 3).
2. From inside the hull, slide the washer onto the housing.
Stainless steel housing in a metal hull—Be sure the washer contacts
the hull. Do not tighten the hull nut with the washer against the isolation
bushing, as the housing will not be firmly installed. If necessary, sand
the isolation bushing until the washer rests against the hull.
3. Screw the hull nut in place.
Plastic hull nut—Hand tighten only. Do not over tighten.
Metal hull nut—Tighten with slip-joint pliers.
Cored fiberglass hull—Do not over tighten, crushing the hull.
Wood hull—Allow for the wood to swell before tightening the hull nut.
4. Remove any excess marine sealant on the outside of the hull to ensure
smooth water flow under the multisensor.
5. The O-rings must be intact and well lubricated to make a watertight
seal. After the marine sealant cures, inspect the O-rings, including the
YELLOW O-ring, on the insert (replace if necessary) and lubricate them
with the silicone lubricant supplied. Also lubricate the bore of the
housing above the valve.
6. The insert must be fully inserted into the housing and the cap nut
screwed on completely to make a watertight seal. Slide the
paddlewheel insert into the housing with the arrow on the top pointing
forward toward the bow. Screw the cap nut several turns until the
threads are engaged. Being sure the arrow on the top of the insert and
the cable exit are pointing forward toward the bow, continue to tighten
the cap nut completely. Be careful not to rotate the housing and disturb
the sealant. Hand tighten only. Do not over tighten.
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. Thread the wire
through the eye a second time. Then lead the wire through the eye in
the insert. 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 one eye in the cap
nut. Thread the wire through the eye a second time. Then lead the wire
counterclockwise and through the eye in the insert. Twist the wire
securely to itself.
Installing in Housing WITHOUT Valve
To create a watertight seal in a housing that does NOT have a
valve, the insert must have a BLACK O-ring near the top. Use
Replacement O-ring Kit 20-519-01 and follow the instructions
supplied.
Cable Routing & Connecting
CAUTION: If your multisensor 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 No. 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 multisensor’s warranty.
1. Route the cable to the instrument being careful not to tear the cable
jacket when passing it through the bulkhead(s) and other parts of the
boat. Use grommets to prevent chafing. To reduce electrical
interference, separate the multisensor cable from other electrical wiring
and the engine. Coil any excess cable and secure it in place with cable
ties to prevent damage.
2. Refer to the instrument owner’s manual to connect the multisensor to
the instrument.
Checking for Leaks
When the boat is placed in the water, immediately check around the
multisensor for leaks. Note that very small leaks may not be readily
observed. Do not to leave the boat in the water for more than 3 hours before
checking it again. 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 pages 2 and 3).
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 4).
3. From inside the hull, use a 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.
3
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
Copyright © 2005 Airmar Technology Corp