Airmar Tilted Element DT800 User manual

Follow the precautions below for optimal
product performance and to reduce the risk of
property damage, personal injury, and/or death.
WARNING: Always wear safety glasses, a dust mask, and
ear protection when installing.
WARNING: The valve is not a watertight seal! Always
install the insert or blanking plug. Be sure it is fully inserted
into the housing and the cap nut is screwed on completely
for a watertight seal.
WARNING: All the O-rings must be intact and well lubricated
to make a watertight seal. Do not dry fit the insert in the
housing. Attempting to install the insert without lubricating all
O-rings will damage them, possibly preventing full insertion
and a watertight seal.
WARNING: The YELLOW O-ring must be in place near the
top of the insert to make a watertight seal.
WARNING:To retrofit the insert in a housing without a
valve, the insert must have a BLACK O-ring near the top to
make a watertight seal.
WARNING:Always attach the safety wire to prevent the
insert or blanking plug from backing out in the unlikely event
that the cap nut fails or is screwed on incorrectly.
WARNING: Immediately check for leaks when the boat is
placed in the water. Do not leave the boat unchecked for
more than three hours. Even a small leak may allow
considerable water to accumulate.
WARNING: 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.
CAUTION: Never pull, carry, or hold the sensor by its cable;
this may sever internal connections.
CAUTION: The arrow on the top of the insert must point
toward the keel/centerline of the boat. This will align the
angle of the element inside the transducer with the deadrise
angle of your hull.
CAUTION: Plastic housing—Never use a fairing with a
plastic housing; the protruding sensor would be vulnerable
to damage from impact.
CAUTION: Metal housing—Never install a metal housing in
a vessel with a positive ground system.
CAUTION: Stainless steel housing in a metal hull—A
stainless steel housing must be isolated from a metal hull to
prevent electrolytic corrosion. Use the isolation bushing
supplied.
CAUTION: Never use solvents. Cleaner, fuel, sealant, paint,
and other products may contain solvents that can damage
plastic parts, especially the transducer’s face.
CAUTION: Never power sand or pressure wash the sensor. It
may weaken the structure or damage the internal components.
Thru-Hull: Retractable with Valve &Temperature Sensor
Tilted Element™Transducer
Tilt Angles: 0°, 12°, 20°
Model: DT800
Patent http://www.airmar.com/patent.html
D-17-431-01-rev.9 17-431-01-rev.9 01/20/22
Important
Read the instructions completely before proceeding with the
installation. These instructions supersede any other instructions in
your instrument manual if they differ.
Applications
•Plastic housing recommended for fiberglass or metal hull only.
Never install a plastic housing in a wood hull since swelling of
the wood can fracture the plastic.
•Bronze housing recommended for fiberglass or wood hull.
Never install a bronze housing in an metal hull because
electrolytic corrosion will occur.
•Stainless steel housing compatible with all hull materials.
Recommended for aluminum hulls to prevent electrolytic
corrosion provided the stainless steel housing is isolated from
the metal hull.
Match Tilt Angle of Transducer to Deadrise Angle
Be sure your transducer model matches the deadrise angle of
your hull at the mounting location. See the top of the transducer
insert for the tilt angle (Figure 1). Measure the deadrise angle of
your hull at the selected mounting location (Figure 2).
• 0° model for deadrise angles from 0° to 7°
• 12° model for deadrise angles from 8° to 15°
• 20° model for deadrise angles from 16° to 24°
Figure 2. Deadrise angle of the hull
transom view deadrise angle
slope of hull
parallel to waterline
Figure 1. Top of insert
12° model 20° model
Copyright © 2006 Airmar Technology Corp.
Copyright © 2005 Airmar Technology Corp.
0° model
plastic
low profile
P617V housing
Smart™ Sensor
OWNER’S GUIDE & INSTALLATION INSTRUCTIONS
Record the information found on the cable tag for future reference.
Part No._________________Date___________Frequency________kHz

planing hulls
Figure 3.
full keel sailboats
large displacement hulls small displacement hulls
fin keel sailboats
Best location for transducer
Copyright © 2005 Airmar Technology Corp
stepped hull
outboard and I/O
Tools & Materials
Safety glasses
Dust mask
Ear protection
Angle finder or smart device
Water-based anti-fouling coating (mandatory in salt water)
Electric drill [Ø 10mm (3/8") or larger chuck capacity]
Drill bit: Ø 3mm or 1/8"
Hole saw: Ø 51mm or 2" (plastic or metal housing in non-metal hull)
Ø 57mm or 2-1/4" (stainless steel housing in a metal hull)
Sandpaper
Mild household detergent or weak solvent (such as alcohol)
File (installation in a metal hull)
Marine sealant (suitable for below waterline)
Slip-joint pliers (installing a metal housing)
Grommet(s) (some installations)
Cable ties
Installation in a cored fiberglass hull (page 4):
Hole saw for hull interior: Ø 60mm or 2-3/8"
Fiberglass cloth and resin
or Cylinder, wax, tape, and casting epoxy
Mounting Location
CAUTION: Do not mount the sensor in line with or near water
intake or discharge openings or behind strakes, fittings, or hull
irregularities that may disturb the water flow.
• The water flowing under the hull must be smooth with a
minimum of bubbles and turbulence, especially at high speeds.
• The sensor must be continuously immersed in water at all
speeds.
• The transducer beam must be unobstructed by the keel or
propeller shaft(s).
• Choose a location away from interference caused by power and
radiation sources such as: the propeller(s) and shaft(s), other
machinery, other echosounders, and other cables. The lower
the noise level, the higher the echosounder gain setting that
can be used.
• Choose an accessible spot inside the vessel with adequate
space for the height of the housing, tightening the nuts, and
removing the insert. Allow a minimum of 280mm (11").
Boat Types (Figure 3)
•Displacement hull powerboats—Locate the sensor amidships
near the centerline. The side of the hull where the propeller
blades are moving downward is preferred.
•Planing hull powerboats—Mount the sensor well aft, on or
near the centerline, and well inboard of the first set of lifting
strakes to ensure that the transducer will be in contact with the
water at high speeds. The side of the hull where the propeller
blades are moving downward is preferred.
Outboard and I/O—Mount just forward of the engine(s).
Inboard—Mount well ahead of the propeller(s) and shaft(s).
Stepped hull—Mount just ahead of the first step.
Boat capable of speeds above 25kn (29MPH)—Review the
installation location and operating results of similar boats before
proceeding.
•Fin keel sailboats—Mount on or near the centerline and
forward of the fin keel 300 to 600mm (1 to 2').
• Full keel sailboats —Locate amidships and away from the keel.
Anti-fouling Coating
Surfaces exposed to saltwater
must be covered with an anti-
fouling coating. Use only water-
based anti-fouling coating made
for transducers. Never use
ketone-based paint, since
ketones can attack many plastics
possibly damaging the sensor.
It is easier to brush on anti-
fouling coating before
installation, but allow sufficient
drying time. Re-coat every 6
months or at the beginning of
each boating season. Coat the
following surfaces (Figure 4):
• Outside wall of the insert
below the lower O-ring
• Exposed end of the insert
• Exterior flange of the housing
• Bore of the housing up 30mm
(1-1/4")
• Blanking plug below the lower
O-ring including the exposed
end.
Installation
Hole Drilling
Cored fiberglass hull—Follow separate instructions on page 4.
1. Drill a Ø 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 boat.
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 will contact the hull and up the sidewall
of the housing (Figure 5). The sealant must extend 6mm (1/4")
higher than the combined thickness of the hull, the washer, and
the hull nut. This will ensure there is sealant in the threads to seal
the hull and to hold the hull nut securely in place.
2
Figure 4. Anti-fouling coating
Copyright © 2006 - 2022 Airmar Technology Corp.
outside wall
bore up exterior
O-ring
below lower
30mm (1-1/4") of flange
insert
housing
exposed end
yellow O-ring
(under cap nut)
O-ring

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 isolation 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 (Figure 5).
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 housing—Do not clamp tightly possibly causing the
housing to fracture.
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 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 sensor.
5. All the O-rings must be intact and well lubricated to make a
watertight seal. After the marine sealant cures, inspect the
O-rings on the insert (replace if necessary) and lubricate them
with the silicone lubricant supplied (Figure 7). Be sure the
YELLOW O-ring is in place near the top. 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 (Figure 5).
Slide the insert into the housing with the arrow on the top
pointing toward the KEEL/centerline of the boat (Figure 1).
7. Screw the cap nut several turns until the threads are engaged
(Figure 5). Being sure the arrow on the top of the insert and the
cable exit are pointing toward the keel/centerline, 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.
8. 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.
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 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 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 sensor’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 chaffing. To reduce
electrical interference, separate the sensor 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 sensor to
the instrument.
Checking for Leaks
When the boat is placed in the water, immediately check around
the 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” immediately (page 2).
3
marine sealant on flange
Figure 5. Bedding and installing
cap nut
washer
hull
plastic housing
safety wire
housing
hull nut
insert
marine sealant on flange
stainless steel housingmetal housing
isolation
bushing
washer
and sidewall of housing
(plastic)
marine sealant on flange
cap nut
hull
safety wire
housing
insert
(plastic)
hull nut
Copyright © 2006 - 2020 Airmar Technology Corp.
KEEL ►
and sidewall of housing and sidewall of housing
non-metal hull metal hull
and isolation bushing where it contacts the hull
P617V B617V SS617V
solid fiberglass or metal hull

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 Ø 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 Ø 51mm or 2" hole saw, cut the hole from outside the hull
through the outer skin only (Figure 6).
3. From inside the hull using a Ø 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” (page 2).
Operation & Maintenance
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 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 install the insert or the blanking plug secured
with the cap nut and 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. All 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 (Figure 7).
2. Remove the insert from the housing by removing the safety wire
and unscrewing the cap nut (Figure 5). This will raise the insert.
Remove the insert with a slow pulling motion. Replace it by
sliding the blanking plug into the housing.
NOTE: In the very unlikely event that the valve breaks, replace
the housing the next time the boat is hauled.
3. With the blanking plug 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: The blanking plug must be fully inserted in the housing
and the cap nut screwed on completely for a watertight seal.
4. 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.
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,
possibly cracking the plastic.
Cleaning & Replacing O-rings
Aquatic growth can accumulate rapidly on the sensor’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.
All the O-rings must be intact and well lubricated to make a
watertight seal. Install the O-rings on the insert and blanking plug
as shown (Figure 7).
Replacement Sensor & Parts
The information needed to order a replacement Airmar sensor 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 USA
Tel: [phone]
Email: [email protected]
Airmar EMEA Europe, Middle East, Africa
Tel: [phone]
Email: [e-mail]
Figure 6. Preparing a cored fiberglass hull
inner skin
core
outer skin
solid or hollow cylinder
pour in
casting
epoxy
Ø 9-12 mm
(3/8-1/2")
larger than the
hole through the
hull’s outer skin
hull thickness
Copyright © 2004 - 2022 Airmar Technology Corp.
Figure 7. Replacing the O-rings
blanking
insert
yellow
O-ring
small
black
plug
O-ring(s)
Copyright © 2005 - 2022 Airmar Technology Corp.
4
NOTE: O-rings
must be intact
and well
lubricated to
make a watertight
seal.
Copyright © 2006 - 2022 Airmar Technology Corp. All rights reserved.
35 Meadowbrook Drive, Milford, New Hampshire 03055-4613, USA
www.airmar.com