OWNER’S GUIDE & INSTALLATION INSTRUCTIONS

Thru-Hull Mount: 600W, Low-profile or Flush Record the information found on the cable tag for future reference.
Part No._________________Date___________Frequency________kHz
Depth or Depth & Temperature Transducer
09/14/21

retractable flush low-profile

Models: B17, B117, low-profile
B17
P217 P319

P17, P19, P217, P314, P319

Patent http://www.airmar.com/patent.html
17-006-01-rev.16

Follow the precautions below for optimal

product performance and to reduce the risk of
Applications
D- 17-006-01-rev.16

property damage, personal injury, and/or death.

• Best performance on hull deadrise angle through 7°.
Can accommodate up to a 12° deadrise angle.
WARNING: Always wear safety glasses, a dust mask,
and ear protection when installing. • Plastic housing recommended for fiberglass or metal hull only.
Never install a plastic housing in a wood hull since swelling of
WARNING: Immediately check for leaks when the the wood may fracture the plastic.
boat is placed in the water. Do not leave the boat • Bronze housing recommended for fiberglass or wood hull.
unchecked for more than three hours. Even a small Never install a bronze housing in a metal hull because
leak may allow considerable water to accumulate. electrolytic corrosion will occur.
WARNING: Retractable models—All the O-rings
must be intact and well lubricated to make a Tools & Materials
watertight seal. Do not dry fit the insert in the Safety glasses
housing. Attempting to install the insert without Dust mask
lubricating all the O-rings may damage them, possibly Ear protection
preventing full insertion and a watertight seal. Electric drill [Ø 10mm (3/8") or larger chuck capacity}
Drill bit: Ø 3mm or 1/8"
WARNING: Retractable models—Always attach the
safety wire to prevent the insert or blanking plug from Hole saw (see table below)
backing out in the unlikely event that the cap nut fails Countersink tool (installing a flush housing)
or is screwed on incorrectly. Sandpaper
Mild household detergent or weak solvent (such as alcohol)
WARNING: B117 and P319—Do not use the spacer File (installation in a metal hull)
if there is insufficient space to tighten the nut, or it is Marine sealant (suitable for below waterline)
within 11mm (1/2") of the top of the housing. Additional washer [for aluminum hull less than 6mm (1/4") thick]
CAUTION: Never pull, carry, or hold the transducer by Slip-joint pliers (installing a metal housing)
its cable. This may sever internal connections. Grommet(s) (some installations)
Cable ties
CAUTION: Plastic housing—Never use a fairing with Water-based anti-fouling coating (mandatory in saltwater)
a plastic housing; the protruding sensor would be Installation in a cored fiberglass hull (page 4):
vulnerable to damage from impact. Hole saw for hull interior: (see table below)
Fiberglass cloth and resin
CAUTION: Metal housing—Never install a metal
housing in a vessel with a positive ground system. or Cylinder, wax, tape, and casting epoxy

CAUTION: Never use solvents. Cleaner, fuel, sealant, Identify Your Model
paint, and other products may contain solvents that can The model name is printed on the cable tag.
damage plastic parts, especially the transducer’s face.
Minimum Cored Fiberglass Hull
Model Outside Hull
vertical space Hull Interior
CAUTION: Never power sand or pressure wash the (Housing)
inside the hull
Ø Hole Saw
Ø Hole Saw
sensor. It may weaken the structure or damage the
Low-profile:
internal components. B117
95mm (3-3/4") Ø 51mm or 2" Ø 60mm or 2-3/8"
P19
IMPORTANT: Read the instructions completely P319
before proceeding with the installation. These Retractable
instructions supersede any other instructions in your Low-profile:
200mm (8") Ø 51mm or 2" Ø 60mm or 2-3/8"
B17
instrument manual if they differ. P17
Retractable Flush:
P217 200mm (8") Ø 51mm or 2" Ø 60mm or 2-3/8"
P314
 Installation
Hole Drilling
Cored fiberglass hull—Follow separate instructions on page 3.

large displacement hulls 1. Drill a Ø 3 mm or 1/8" pilot hole from inside the hull. If there is a
small displacement hulls
rib, strut, or other hull irregularity near the selected mounting
location, drill from the outside.
planing hulls
2. Using the appropriate size outside hull hole saw, cut a hole
perpendicular to the hull from outside the boat (see table on
stepped hull
page 1).
outboard and I/O
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
fin keel sailboats household detergent or a weak solvent (alcohol) before sanding.
Metal hull—Remove all burrs with a file and sandpaper.
Bedding
full keel sailboats CAUTION: Be sure the surfaces to be bedded are clean and dry.
Apply a 2mm (1/16") thick layer of marine sealant around the
Figure 1. Best location for transducer flange and up the sidewall of the housing (Figure 2). The sealant
Copyright © 2005 Airmar Technology Corp.
must extend 6mm (1/4") higher than the combined thickness of
the hull, washer, any spacer, and the hull nut. This will ensure
Mounting Location there is marine sealant in the threads to seal the hull and to hold
the hull nut securely in place.
Guidelines
Installing
CAUTION: Do not mount the transducer in line with or near water
NOTE: Ignore any arrows on the housing, insert, and blanking plug.
intake or discharge openings or behind strakes, fittings, or hull
irregularities that will disturb the water flow. 1. From outside the hull, push the housing (and cable if applicable)
into the mounting hole using a twisting motion to squeeze out
• The water flowing under the hull must be smooth with a
minimum of bubbles and turbulence, especially at high speeds. excess marine sealant (Figure 2).
• The transducer must be continuously immersed in water at all 2. From inside the hull, slide the washer onto the housing.
speeds. B117 and P319—Also slide the spacer onto the housing and
• The transducer beam must be unobstructed by the keel or rest it against the washer. Do not use the spacer if there is
propeller shaft(s). insufficient space to tighten the nut or it is within 11mm (1/2") of
• Choose a location away from interference caused by power and the top of the housing.
radiation sources such as: the propeller(s) and shaft(s), other Aluminum hull less than 6mm (1/4") thick—If necessary, use
machinery, other echosounders, and other cables. The lower an additional rubbery, fiberglass, or plastic washer. Never use
the noise level, the higher the echosounder gain setting that
bronze because electrolytic corrosion will occur. Never use wood
can be used.
because it will swell, possibly fracturing the plastic housing.
• Choose a location with a minimal deadrise angle, so the
transducer beam will be aimed at the bottom. 3. Screw the hull nut in place.
• Choose an accessible spot inside the vessel with adequate Plastic housing—If your housing has wrenching flats, do not
vertical space for the height of the housing, tightening the nuts, clamp tightly possibly causing the housing to fracture.
and removing any insert (see the table on page 1). Plastic hull nut—Hand tighten only. Do not over tighten.
Metal hull nut—Tighten with slip-joint pliers.
Boat Types (Figure 1) Cored fiberglass hull—Do not over tighten, crushing the hull.
• Displacement hull powerboats—Locate amidships near the Wood hull—Allow the wood to swell before tightening the hull nut.
centerline. The side of the hull where the propeller blades are
moving downward is preferred. 4. Remove any excess marine sealant on the outside of the hull to
ensure smooth water flow under the transducer.
• Planing hull powerboats—Mount well aft, on or near the
centerline, and well inboard of the first set of lifting strakes to Retractable Models Only
ensure that the transducer will be in contact with the water at 1. All the O-rings must be intact and well lubricated to make a
high speeds. The side of the hull where the propeller blades are watertight seal. After the marine sealant cures, inspect the
moving downward is preferred. O-rings on the transducer insert (replace if necessary) and
Outboard and I/O—Mount just forward of the engine(s).
lubricate them with the silicone lubricant supplied.
Inboard—Mount well ahead of the propeller(s) and shaft(s).
Stepped hull—Mount just ahead of the first step. 2. Slide the insert into the housing. Seat the insert into place with a
Boat capable of speeds above 25kn (29MPH)—Review the twisting motion until the key fits into the notch. Be careful not to
installation location and operating results of similar boats before rotate the housing and disturb the marine sealant. Screw the cap
proceeding. nut in place. Hand tighten only. Do not over tighten.
• Fin keel sailboats—Mount on or near the centerline and D800, DT800—Be sure the insert is fully inserted into the
forward of the fin keel 300 to 600mm (1–2'). housing. Screw the cap nut several turns until the threads are
• Full keel sailboats—Locate amidships and away from the keel engaged. Continue to tighten the cap nut completely for a
at the point of minimum deadrise angle. watertight seal. Hand tighten only. Do not over tighten.
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 fiberglass hull fiberglass or wood hull fiberglass or wood hull
plastic or bronze housing flush housing metal housing
(P319/B117 shown) retractable insert retractable insert
(P217 shown) (B17 shown)
pull ring pull ring
transducer insert
transducer insert
safety wire
safety wire
cap nut
cap nut (plastic)
housing housing
housing
hull nut hull nut
(plastic/metal) hull nut
washer
spacer washer
washer hull
hull
hull

marine sealant on flange and marine sealant on flange and marine sealant on flange and
side wall of housing side wall of housing side wall of housing

Figure 2. Bedding and installing

Copyright © 2006 - 2010 Airmar Technology Corp.

3. Attach the safety wire to prevent the insert from backing out in the Installation in a Cored Fiberglass Hull
unlikely event that the cap nut fails or is screwed on incorrectly
(Figure 2). The core (wood or foam) must be cut and sealed carefully. The
core must be protected from water seepage, and the hull must be
Plastic housing—Attach the safety wire to one eye in the hull reinforced to prevent it from crushing under the hull nut allowing
nut. Keeping the wire taut throughout, lead the wire in a the housing to become loose.
counterclockwise direction and thread it through one eye in the
cap nut, the pull ring/eye in the insert, the second eye in the cap CAUTION: Completely seal the hull to prevent water seepage into
nut, and the second eye in the hull nut. Twist the wire securely the core.
to itself.
1. Drill a Ø 3 mm or 1/8" pilot hole from inside the hull. If there is a
Metal housing—Wrap one end of the safety wire tightly around rib, strut, or other hull irregularity near the selected mounting
the housing and twist it together with the long end. Keeping the location, drill from the outside (Figure 3). (If the hole is drilled in
wire taut throughout, lead the wire straight up and through the the wrong location, drill a second hole in a better location. Apply
eye in the cap nut. Loop the wire through the pull ring/eye in the masking tape to the outside of the hull over the incorrect hole
insert and twist it securely to itself. and fill it with epoxy.)

Cable Routing & Connecting 2. Using the appropriate size outside hull hole saw, cut a hole from
outside the hull through the outer skin only (see table on page 1).
CAUTION: If your transducer came with a connector, do not
3. From inside the hull using the appropriate size hull interior hole
remove it to ease cable routing. If the cable must be cut and
saw, cut through the inner skin and most of the core (see table on
spliced, use Airmar’s splash-proof Junction Box No. 33-035 and
page 1). The core material can be very soft. Apply only light
follow the instructions provided. Removing the waterproof
pressure to the hole saw after cutting through the inner skin to
connector or cutting the cable, except when using a watertight
avoid accidentally cutting the outer skin.
junction box, will void the sensor warranty.
4. Remove the plug of core material, so the inside of the outer skin
1. Route the cable to the instrument, being careful not to tear the and the inner core of the hull is fully exposed. Sand and clean the
cable jacket when passing it through the bulkhead(s) and other inner skin, core, and the outer skin around the hole.
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
Ø 9 to 12 mm
secure it in place using cable ties to prevent damage. (3/8-1/2")
pour in larger than the
casting hole through the
2. Refer to the echosounder owner’s manual to connect the epoxy hull’s outer skin inner skin
transducer to the instrument.

core
Checking for Leaks
hull thickness
When the boat is placed in the water, immediately check around
the transducer 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 solid or hollow cylinder outer skin
be considerable bilge water accumulation after 24 hours. If a leak
is observed, repeat “Bedding” and “Installing” immediately Figure 3. Preparing a cored fiberglass hull
(page 2). Copyright © 1996 - 2021 Airmar Technology Corp.

3
5. If you are skilled with fiberglass, saturate a layer of fiberglass 1. All the O-rings must be intact and well lubricated to make a
cloth with a suitable resin and lay it inside the hole to seal and watertight seal. On the blanking plug, inspect the O-rings
strengthen the core. Add layers until the hole is the correct (replace if necessary) and lubricate them with the silicone
diameter. lubricant supplied or petroleum jelly (Figure 4).
Alternatively, a hollow or solid cylinder of the correct diameter 2. Remove the transducer insert from the housing by removing the
can be coated with wax and taped in place. Fill the gap between safety wire and unscrewing the cap nut (Figure 2).
the cylinder and hull with casting epoxy. After the epoxy has set,
3. With the blanking plug ready in one hand, pull the transducer
remove the cylinder.
insert most of the way out. Remove the insert and rapidly replace
6. Sand and clean the area around the hole, inside and outside, to it with the blanking plug. Seat it into place with a pushing twisting
ensure that the marine sealant will adhere properly to the hull. If motion until the key fits into the notch in the housing. With
there is any petroleum residue inside the hull, remove it with practice, only 250ml (10oz.) of water will enter the boat. Screw the
either mild household detergent or a weak solvent (alcohol) cap nut in place. Hand tighten only. Do not over tighten.
before sanding.
D800, DT800—Be sure the blanking plug is fully inserted into the
7. Proceed with “Bedding” and “Installing” (page 2).
housing. Screw the cap nut several turns until the threads are
Anti-fouling Coating engaged. Continue to tighten the cap nut completely for a
watertight seal. Hand tighten only. Do not over tighten.
Surfaces exposed to saltwater must be covered with an anti-
fouling coating. Use water-based anti-fouling coating made for 4. Reattach the safety wire to prevent the blanking plug from
transducers only. Never use ketone-based paint since ketones backing out in the unlikely event that the cap nut fails or is
can attack many plastics possibly damaging the transducer. screwed on incorrectly.
Brush on anti-fouling coating every 6 months or at the beginning Replacing the O-rings
of each boating season.
All the O-rings must be intact and well lubricated to make a
Retractable Models: Coat the following surfaces watertight seal. Inspect the spare O-rings and lubricate them with
• Outside wall of the insert below lower O-ring and exposed end silicone lubricant or petroleum jelly. Replace the O-rings.
• Bore of the housing up 30mm (1-1/4”) Winterizing
• Exterior flange of the housing After the boat has been hauled for winter storage, remove the
blanking plug to let the water drain away before reinserting it. This
• Blanking plug below the lower O-ring including the exposed end
will prevent any water from freezing around the blanking plug,
possibly cracking the plastic.
Maintenance, Parts & Replacement
Cleaning Replacement Transducer & Parts
Aquatic growth can accumulate rapidly on the transducer’s face, The information needed to order a replacement transducer is
reducing its performance within weeks. Clean the surface with a printed on the cable tag. Do not remove this tag. When ordering,
Scotch-Brite® scour pad and mild household detergent, being specify the part number, date, and frequency in kHz. For
careful to avoid making scratches. If the fouling is severe, lightly convenient reference, record this information on the top of page one.
wet sand the surface with fine grade wet/dry paper. Lost, broken, and worn parts should be replaced immediately.
Retractable Models Obtain parts from your instrument manufacturer or marine dealer.
Using the Blanking Plug Gemeco USA
To protect the insert, use the blanking plug: Tel: 803-693-0777
• When the boat will be kept in saltwater for more than a week. Email: sales@gemeco.com
• When the boat will be removed from the water. Airmar EMEA Europe, Middle East, Africa
• When aquatic growth buildup on the insert is suspected due to Tel: +33.(0)2.23.52.06.48
inaccurate readings from the instrument. Email: sales@airmar-emea.com

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

www.airmar.com
Copyright © 2006 - 2021 Airmar Technology Corporation
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