Installation Instructions

ManualsBrandsFuruno ManualsTransducersFuruno 525T-LTD/20

planing hulls

Figure 3.

full keel sailboats

large displacement hulls

small displacement hulls

fin keel sailboats

Best location for transducer

stepped hull

outboard and I/O

Identify Your Model

The model name is printed on the cable tag.

Tools & Materials

Safety goggles

Dust mask

Angle finder

Electric drill with 10mm (3/8") or larger chuck capacity

Drill bit: 3mm or 1/8"

Hole saw (see table above)

Countersink tool (installing SS565)

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

Water-based anti-fouling paint (mandatory in salt water)

Installation in a cored fiberglass hull (see page 4):

Hole saw for hull interior (see table above)

Fiberglass cloth and resin

or Cylinder, wax, tape, and casting epoxy

Model

(Housing)

Hull Material

Outside Hull

Hole Saw Size

Cored Fiberglass Hull

Hull Interior

Hole Saw Size

P19

fiberglass

metal

51mm or 2" 60mm or 2-3/8"

B150M

B619

SS150M

SS619

fiberglass

wood

51mm or 2" 60mm or 2-3/8"

SS150M

SS619

metal 57mm or 2-1/4" NA

B60

SS60

SS56

fiberglass

wood

60mm or 2-3/8" 80mm or 3-1/8"

B75H/M/L

fiberglass

wood

70mm or 2-3/4" 80mm or 3-1/8"

SS60

SS565

metal 70mm or 2-3/4" NA

Mounting Location

CAUTION: Do not mount in line with or near water intake or

discharge openings or behind strakes, fittings, or other hull

irregularities that will disturb the water flow.

CAUTION: Do not mount in line with trailer rollers or bunks that

may damage 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.

• CHIRP transducer—Mount in a cool well-ventilated area away

from the engine to avoid overheating.

Hull Types (see Figure 3)

• 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

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.

Installation

Hole Drilling

Cored fiberglass hull—Follow separate instructions on page 4.

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.

2. Using the appropriate size outside hull hole saw, cut a hole

from outside of the hull perpendicular to the hull surface (see

table above).

SS565—Use a countersink tool to create 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

of the housing that contacts the hull and up the sidewall of the

housing (see Figure 4 or 5). The sealant must extend 6mm (1/4")

higher than the combined thickness of the hull, washer(s), hull nut,

and any spacer. This will ensure there is marine sealant in the

threads to seal the hull and to hold the hull nut securely in place.