Airmar ST600 User manual

17-038-01 rev. 03 10/01
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.
IMPORTANT : Please read these instructions
completely before proceeding with the installation.
These directions supersede any other instructions in
your instrument manual if they differ.
Thru-Hull Speed &Temperature Sensor
withValve
Model ST600
U.S. Patents: 4,898,029; 5,186,050. Australian Patent 605,281.
Canadian Patent 1,313,775. Japanese Patent 1851014
Applications
• Plastic housing recommended for fiberglass or metal hulls only.
Never install a plastic thru-hull sensor in a wood hull, since
swelling of the wood may overstress the plastic causing a
fracture.
•
Bronze housing recommended for wood or fiberglass hulls only.
Never install a bronze housing in a metal hull because electrolytic
corrosion will occur.
•
Never install a metal housing in a vessel with a positive ground
system.
Tools and Materials
Water based or mineral spirits based anti-fouling paint
(
mandatory in salt water )
Safety goggles
Dust mask
Electric drill with 10mm (3/8") or larger chuck capacity
Drill bit: 3mm
or 1/8"
Hole saw: 51mm
or 2"
Sandpaper
Mild household detergent
or weak solvent (alcohol)
Marine sealant
Additional washer (some installations)
Slip-joint pliers for metal housing
Zip-ties
Installation in a cored fiberglass hull (see page 3)
Hole saw for hull interior: 60mm
or 2-3/8"
Fiberglass cloth and resin
or Cylinder, wax, tape, and casting epoxy
Preparation
Pre-InstallationTest
Connect the sensor to the instrument and spin the paddlewheel.
Check for a speed reading and the approximate air temperature.If
there is no reading or it is inaccurate, return the instrument to your
place of purchase.
OWNER’S GUIDE & INSTALLATION INSTRUCTIONS
Figure 1. Anti-fouling paint
outside wall
paddlewheel
paddlewheel
inside bore of
exterior lip
Anti-fouling Paint
Marine 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 or
mineral spirits based
anti-fouling paint only. Never use ketone
based anti-fouling paint, since ketones attack many plastics
possibly damaging the sensor.
It is easiest to apply anti-fouling paint before installation, but allow
sufficient drying time.Reapply paint every 6 months or at the
beginning of each boating season. Paint the following surfaces
(see Figure 1):
• Outside wall of paddlewheel insert below lowest O-ring
• Paddlewheel cavity
• Paddlewheel
• Bore of housing up 30mm (1-1/4")
• Exterior lip of housing
• Blanking plug below lowest O-ring including the exposed end
Assembly
Slide the cap nut along the cable until it rests on the top of the
paddlewheel insert. Attach the pull ring to the insert capturing the
cap nut (see Figure 2).Similarly attach the pull ring to the
blanking plug capturing the cap nut.
lowest O-ring
below
cavity
housing up 30mm (1-1/4")
Figure 2. Assembly
paddlewheel
insert
of housing
paddlewheel
insert
housing
pull
ring
cap
nut

Mounting Location
Turbulence-free water must flow over the paddlewheel at all
speeds.Choose an accessible spot inside the vessel.Allow a
minimum of 200mm (8") of headroom for the height of the
housing, tightening the nuts, and removing the insert.
•
Displacement hull powerboats —Locate amidships near the
centerline.
•
Planing hull powerboats —Mount well aft to insure that it is in
contact with the water at high speeds.
•
Fin keel sailboats —Mount on or as close as possible to the
centerline and forward of the fin keel 300–600mm(1–2').
•
Full keel sailboats —Locate amidships and away from the keel
at the point of minimum deadrise.
Caution : Do not mount the sensor in an area: of turbulence or
bubbles:near water intake or discharge openings;behind strakes,
fittings, or hull irregularities; or behind eroding paint (an indication
of turbulence).
Caution : Never mount the sensor directly ahead of a depth
transducer, since turbulence generated by the paddlewheel’s
rotation will adversely affect the depth transducer’s performance,
especially at high speeds.
Installation
Cored fiberglass hull —Follow separate instructions on page 3.
Hole Drilling
Warning : Always wear safety goggles and a dust mask.
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 pilot 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.
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.
Bedding
Apply a 2mm (1/16") thick layer of marine sealant around the lip of
the housing that contacts the hull. Apply marine sealant to the
sidewall of the housing, 6mm (1/4") higher than the combined
thickness of the hull, washer, and 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.
Installing
Caution : Never pull, carry, or hold the sensor by the cable as this
may sever internal connections.
1.From outside the hull, push the housing into the mounting hole
using a twisting motion to squeeze out excess sealant (see
Figure 3). Align the arrow on the lip of the housing to point
forward toward the bow.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 the washer onto the housing.
Aluminum hulls less than 6mm (1/4") thick —Use an
additional rubber, plastic, or fiberglass washer.
Never use a
wood backing block, since swelling of the wood can overstress
the plastic housing causing a fracture.
Never use bronze since
electrolytic corrosion will occur.
3.Screw the hull nut in place
being sure the arrow on the lip and the
notch on the upper rim of the housing are still positioned forward
toward the bow (see Figure 7).
Plastic hull nut — Hand-tighten only. Do not over-tighten.
Metal hull nut —Tighten the hull nut with slip-joint pliers.
Wood hull —Allow for the wood to swell.
4.Remove any excess sealant on the outside of the hull to ensure
smooth water flow over the paddlewheel.
Warning:The O-rings must be intact and well lubricated to
make a watertight seal.
5.After the sealant cures, inspect the O-rings on the paddlewheel
insert and lubricate them with the silicone lubricant supplied.
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
lip 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).
Warning : Always 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.
Figure 3. Bedding and installing
plastic housing metal housing
pull ring
safety wire
cap nut
hull nut
washer
hull
paddlewheel paddlewheel
insert
insert
marine
sealant
marine
sealant
(plastic)
2

7. Plastic housing —Attach the safety wire to one eye in the hull
nut.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.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.
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. Cutting the cable or removing the
connector, except when using Airmar’s junction box, will void
the warranty.
8.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.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 zip-ties to prevent
damage.
9.Refer to the instrument owner’s manual to connect the sensor
to the instrument.
Checking for Leaks
Warning: Never install a thru-hull sensor and leave the boat in the
water unchecked for several days.
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 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” on
page 2
immediately .
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.
Warning : Always wear safety goggles and a dust mask.
1.Drill a 3mm or 1/8" pilot hole from inside the hull. If there is a rib,
strut, orother hullirregularitynear theselected 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.
Caution : Completely seal the hull to prevent water seepage
into the core.
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 theValve Works
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.
WARNING:THEVALVE IS NOT AWATERTIGHT SEAL.
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.
Warning:The O-rings must be intact and well lubricated to
make a watertight seal.
1.Inspect (and replace if necessary) the O-rings on the blanking
plug and lubricate them with the silicone lubricant supplied or
petroleum jelly (Vaseline
®
).
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
pushing twisting motion until the key fits into the notch.Screw
the cap nut in place and
hand-tighten only. Do not over-tighten.
Reattach the safety wire.
Figure 4. Preparing a cored fiberglass hull
inner skin
core
outer skinsolid 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

Cleaning the Paddlewheel
Aquatic growth can impede or freeze the paddlewheel’s rotation
and
must be removed.Use a stiff brush or putty knife to remove
the growth and clean the surface with mild household detergent.If
fouling is severe, push out the paddlewheel shaft using a spare
shaft or a 4D finish nail with a flattened point.Then, lightly wet
sand the surface with fine grade wet/dry paper.
Replacing the Paddlewheel and O-rings
The water lubricated paddlewheel bearings have a life of up to 5
years on low-speed boats [less than 10kn (11 MPH)] and 1 year
on high-speed vessels.Paddlewheels can fracture and shafts can
bend due to impact with water borne objects and mishandling in
boat yards. O-rings must be free of abrasions and cuts to ensure
a watertight seal. A replacement Paddlewheel & Valve Kit 33-250
is available (see Figure 5).
1.Using the new paddlewheel shaft, push the old shaft out about
6mm (1/4").With pliers, remove the old shaft (see Figure 6).
2.Place the new paddlewheel in the cavity with the flat side of the
blade facing the same direction as the arrow on the insert top.
3.Tap the new shaft into place until the ends are flush with the insert.
4.Install the
large O-ring near the pull ring, the medium O-ring
below it, and the
small O-ring near the paddlewheel.
5.Place the three remaining O-rings in similar positions on the
blanking plug.
Servicing the Valve Assembly
Should the valve fail, remove it for servicing. A Paddlewheel &
Valve Kit 33-250 is available (see Figure 5).
Warning:The O-rings must be intact and well lubricated to
make a watertight seal.
1. Inspect (replace if necessary) the O-rings on the blanking plug and
lubricate them with silicone lubricant or petroleum jelly (Vaseline
®
).
2.Remove the paddlewheel insert from the housing (see Figure 3).
3.Remove the snap ring from the valve assembly using a
screwdriver to pry the end of the ring free. Lift the ring out (see
Figure 7).
4.Slide the valve assembly upward and out of the housing slowly.
Note :The flap valve retainer pin is a loose slip-fit and may slide
out when the assembly is removed.
5.Hold the cap nut on the blanking plug while sliding it into the
housing with the arrow on the top pointing forward toward the
bow.Seat the plug with a pushing twisting motion until the key fits
into the notch.Screw the cap nut in place and
hand-tighten only.
Do not over-tighten.Reattach the safety wire (see Figure 3).
6.Clean, repair, or replace the valve assembly so the flap valve
moves freely and seats against the valve housing.
7.To reinstall the valve assembly, first reassemble the flap valve in
the valve housing with the retainer pin and spring in place (see
Figure 7).
8.Remove the blanking plug.Slide the valve assembly into the
housing with the flap valve pointing downward.Insert the snap ring
being certain that it locks into the groove in the housing wall.
9.Hold the cap nut on the blanking plug or paddlewheel insert
while sliding it into the housing.
Be sure the arrow on the top is
pointing forward toward the bow.Seat it into place with a
pushing twisting motion until the key fits into the notch.Screw
the cap nut in place and
hand-tighten only. Do not over-tighten.
Reattach the safety wire (see Figure 3).
Warning : Always 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.
Replacement Parts
If you have purchased a plastic housing and have a wood hull or
desire greater strength, purchase an Airmar bronze housing.
Obtain the following parts from your marine dealer or instrument
manufacturer.
Sensor Replacement
The information needed to order a replacement Airmar sensor is
printed on the cable tag.
Do not abrade the marking or remove
this tag.When ordering, specify the part number and date.
Blanking
Plug Kit Cap Nut Hull Nut Housing
& Hull Nut Kit Paddlewheel &Valve Kit
20-600 04-011 04-004 (plastic)
02-030 (bronze) 33-340-02 (plastic) 33-340-01 (bronze) 33-250
AIRMAR
TECHNOLOGY CORPORATION
35 Meadowbrook Drive, Milford, New Hampshire 03055-4613, USA
■
www.airmar.com
snap ring
valve assembly
flap valve
spring
retainer pin
housing
pull ring
Figure 6. Replacing the paddlewheel
BOW
➤
top view
side view
arrow
small O-ring
shaft
flat side
of blade
notch
and O-rings
faces bow
Figure 7. Servicing the
valve assembly
Figure 5. Paddlewheel &
Valve Kit 33-250
large O-ring
medium O-ring
4