Airmar P6 User Manual

INSTALLATION INSTRUCTIONSOWNER’S GUIDE &

Thru-Hull: Low-Profile, Flush & Retractable

Shorty

Models: P6, P7, P8, P208

Follow the precautions below for optimal
product performance and to reduce the risk of
property damage, personal injury, and/or death.

17-273-01 rev. 04 02/06/13

WARNING: Always wear safety goggles and a dust
mask when installing.

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: Retractable models—The O-rings must
be intact and well lubricated to make a watertight seal.

™ Depth Transducer

Record the information found on the cable tag for future reference.

Part No._________________Date___________Frequency_________kH

P7
Low profile

P8
Low profile, retractable

Applications

• Recommended for fiberglass or metal hulls only

• Never install a plastic housing in a wood hull, since swelling of
the wood may fracture the plastic.

• Low profile housing recommended for cruising sailboats and
planing hull powerboats

• Flush housing recommended for racing sailboats and high­speed powerboats

• Accommodates up to a 20° deadrise angle.

WARNING: Retractable models—Always attach the
safety wire to prevent the sensor insert or blanking
plug from backing out in the unlikely event that the cap
nut fails or is screwed on incorrectly.

CAUTION: Never pull, carry, or hold the sensor by its
cable; this may sever internal connections.

CAUTION: Never use a fairing with a plastic housing;
the protruding sensor would be vulnerable to damage
from impact.

CAUTION: The arrow on the top of the transducer
insert and the flange of the housing must point forward
toward the bow.

CAUTION: Never use solvents. Cleaner, fuel, sealant,
paint, and other products may contain solvents that can
damage plastic parts, especially the transducer’s face.

IMPORTANT: Please read the instructions completely
before proceeding with the installation. These
instructions supersede any other instructions in your
instrument manual if they differ.

Tools & Materials

Safety goggles
Dust mask
Electric drill with minimum 10mm (3/8") chuck capacity
Drill bit 3mm or 1/8"
Hole saw 51mm or 2"
Countersink tool (installing P208 flush housing)
Sandpaper
Mild household detergent or weak solvent (such as alcohol)
File (installation in a metal hull)
Marine sealant (suitable for below waterline)
Additional washer [aluminum hull less than 6mm (1/4") thick]
Grommet(s) (some installations)
Cable ties
Water-based antifouling paint (mandatory in salt water)
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

Identify Your Model

The model name is printed on the cable tag.

Hull Thickness

Model Minimum Maximum

P6, P7 (low profile) 6mm (1⁄4") 38mm (11⁄2")

P8 (low profile, retractable) 6mm (1⁄4") 25mm (1")

P208 (flush, retractable) 11mm (7⁄16") 30mm (13⁄16")

large displacement hulls

small displacement hulls

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 300–600 mm (1–2').

• Full keel sailboats—Locate amidships and away from the keel
at the point of minimum deadrise.

planing hulls

outboard and I/O

fin keel sailboats

Figure 1.

Copyright © 2005 Airmar Technolog y Corp.

full keel sailboats

Best location for transducer

stepped hull

Mounting Location

Guidelines

CAUTION: Do not mount the transducer in line with or near water
intake or discharge openings; or behind strakes, fittings or hull
irregularities that may disturb the water flow.

CAUTION: Do not mount the transducer where the boat may be
supported during trailering, launching, hauling, or storage to avoid
damaging the transducer’s face.

• The water flowing under the hull must be smooth with a
minimum of bubbles and turbulence (especially at high speeds).

• The transducer must be continuously immersed in water.

• 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 a location with a minimal deadrise angle, so the
transducer beam will be aimed toward the bottom.

• Choose an accessible spot inside the vessel with adequate
headroom for the height of the housing, tightening the nuts, and
removing any insert.

Model
P6, P7 76mm (3")
Retractable P8, P208 153mm (6")

Boat Types (see Figure 1)

• Displacement hull powerboats—Locate amidships near the
centerline. The starboard side of the hull where the propeller
blades are moving downward is preferred.

• Planing hull powerboats—Mount 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 starboard 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

2

Minimum Headroom

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 a 51 mm or 2" hole saw, cut a hole perpendicular to the hull
from outside the hull.

P208 flush housing — Use a countersink tool to make a “seat” in
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 and up the sidewall of the housing that will contact the hull
(see Figure 2). The sealant must extend 6 mm (1/4") higher than
the combined thickness of the hull, any washer(s), and the hull
nut. This will ensure there is sealant in the threads to seal the hull
and hold the hull nut securely in place.

Installing

1. From outside the hull, push the housing (and cable if applicable)
into the mounting hole using a twisting motion to squeeze out
excess marine sealant. Align the arrow on the flange of the
housing to point forward toward the bow (see Figure 2).

2. From inside the hull, slide any washer(s) onto the housing.

NOTE: Some installations do not have a washer.

Aluminum hull less than 6mm (1/4") thick—Use an additional
rubbery, plastic, or fiberglass washer. Never use bronze
because electrolytic corrosion will occur. Never use wood
because it will swell, possibly fracturing the plastic housing.

3. Screw the hull nut into place, being sure the notch on the upper
rim of the housing is still positioned forward toward the bow.

Hand-tighten only. Do not over-tighten.
Plastic housing—Do not clamp tightly on the wrench flats

possibly fracturing the housing.
Cored Fiberglass Hull—Do not over tighten, crushing the hull.

4. Remove the excess sealant on the outside of the hull to ensure
smooth water flow under the transducer.

Retractable Models

1. After the sealant cures, inspect the O-rings on the transducer
insert (replace if necessary) and lubricate them with the silicone
lubricant supplied (see Figure 3). The O-rings must be intact and
well lubricated to make a watertight seal.

2. Slide the 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 (see Figure 2). 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 marine sealant.

P6 or P7 P8

insert

notch

housing

washer

hull nut

hull

flange

arrow

Figure 2. Bedding and installing—low profile models shown

(some installations)

Copyright © 2004 Airmar Technolog y Corp.

3. Screw the cap nut several turns, then check that the arrow on
the insert is still facing forward toward the bow. Continue to
tighten the cap nut. Hand-tighten only. Do not over tighten.

4. 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 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. Twist the end securely to the wire.

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 chafing. To reduce
electrical interference, separate the transducer 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
transducer to the instrument.

cap nut

safety wire

housing

hull nut

hull

marine sealant on
flange and side wall

arrow

flange

Checking for Leaks

When the boat is placed in the water, immediately check around
the thru-hull transducer 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 page 2).

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 3 mm 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 a hole from outside the hull
through the outer skin only (see Figure 4).

detail

key

notch

Figure 3. Retractable insert

Copyright © 2004 Airmar Technol ogy Corp.

large
O-ring

small
O-ring

9- 12 mm

pour in
casting
epoxy

hull thickness

(3/8-1/2")
larger than the
hole through the
hull’s outer skin

Figure 4. Preparing a cored fiberglass hull

Copyright © 2005 Airmar Technol ogy Corp.

inner skin

core

outer skinsolid or hollow cylinder

3

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.

4. Remove the plug of core material, so the inside of the outer skin
and the inner core of the hull is 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 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” and “Installing” on page 2.

Maintenance, Parts & Replacement

Antifouling Paint

Surfaces exposed to salt water must be coated with antifouling
paint. Use water-based antifouling paint only. Never use ketone
based antifouling paint, since ketones can attack many plastics
possibly damaging the transducer. Reapply antifouling paint every
6 months or at the beginning of each boating season.

Retractable Models—Paint the following surfaces:

• Outside wall of the insert below lower O-ring and exposed end

• Bore of the housing up 30mm (1-1/4”)

• Exterior flange of the housing

• Blanking plug below the lower O-ring including the exposed end

Retractable Models

Using the Blanking Plug

CAUTION: Do not remove the screws on the top of the

transducer.

2. Remove the transducer insert from the housing by removing the
safety wire from the cap nut (see Figure 2). Unscrew the cap nut.
This will jack the insert out of the housing, removing the cap nut
and insert as a single unit.

3. With the blanking plug ready in one hand, pull the transducer
insert out. Rapidly replace it with the blanking plug. Seat it into
place with a pushing twisting motion until the key fits into the
notch in the housing (see Figure 3). With practice, only 250ml
(10oz.) of water will enter the boat. Screw the cap nut in place
and hand-tighten only. Do not over tighten.

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 (see Figure 2).

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

Aquatic growth can accumulate rapidly on the transducer’s face,
reducing its performance within weeks. Clean it using a Scotch­Brite® scour pad and mild household detergent, being careful to
avoid making scratches. If the fouling is severe, lightly wet sand
the surface with fine grade wet/dry paper.

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, and worn parts should be replaced immediately.

Model

P6, P7 — 09-452 04-004 — — —

P8 retractable 33-360-01 09-452 04-004 04-011 33-519-01 20-291-01

P208 retractable 33-468-01 09-452 04-004 04-011 33-519-01 20-291-01

Housing

& Nut

Rubber
Washer

Hull

Nut

Cap

Nut

O-Rings

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 3).

®

AIRMAR

35 Meadowbrook Drive, Milford, New Hampshire 03055-4613, USA

TECHNOLOGY CORPORATION

4

Copyright © 2004 - 2013 Airmar Technology Corp. All rights reserved.

Obtain parts from your instrument manufacturer or marine dealer.

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