Mounting location, Anti-fouling paint, Hull types – Airmar DST800 Retractable without Valve—TRIDUCER® Multisensor User Manual

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Mounting Location

CAUTION: Do not mount near water intake or discharge
openings, or behind strakes, fittings, or hull irregularities.

• The water flowing under the hull must be smooth with a

minimum of bubbles and turbulence (especially at high speeds).

• The multisensor 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 at the bottom.

• Choose an accessible spot inside the vessel with adequate

headroom for the height of the housing, tightening the nuts, and
removing the insert. Allow a minimum of 280mm (11").

Hull 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 insure that the
multisensor 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
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 300–600mm (1–2').

• Full keel sailboats—Locate amidships and away from the keel at

the point of minimum deadrise.

Anti-fouling Paint

Aquatic growth can accumulate rapidly on the multisensor’s surface
reducing performance within weeks. Surfaces exposed to salt water
must be coated with anti-fouling paint. Use water-based anti-fouling
paint only. Never use ketone-based paint, since ketones can attack
many plastics possibly
damaging the sensor.
It is easier 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 ( Figure 2):
• Outside wall of the insert

below the lower O-ring

• Paddlewheel cavity
• Paddlewheel
• 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

planing hulls

Figure 1.

full keel sailboats

large displacement hulls

small displacement hulls

fin keel sailboats

Best location for multisensor

stepped hull

outboard and I/O

marine sealant on flange and

Figure 3. Bedding and installing

cap nut

washer

hull

plastic housing

safety wire

housing

hull nut

insert

marine sealant on flange

stainless steel housing in metal hull

metal housing in non-metal hull

isolation

ring

washer

sidewall of housing

(plastic)

marine sealant on flange

cap nut

hull

safety wire

housing

insert

(plastic)

(metal)

hull nut

BOW

►

and sidewall of housing

and isolation bushing where it contacts the hull

P17

B17

SS577

Figure 2. Anti-fouling paint

outside wall

paddlewheel

bore up

exterior flange

O-ring

below lower

cavity

30mm (1-1/4")

of housing

insert

housing

exposed end