Fishfinder 300C Installation Instructions
Apply marine sealant to all screw
threads to prevent water from
seeping into the transom.
Mount the transducer
cable cover well above
the waterline.
Transducer should extend 1/8" (3.2 mm)
below a fiberglass hull or 3/8" (9.5 mm)
below an aluminum hull.
Ensure that the transducer is
below water level when the boat
is on plane at high speed.
Do not mount the transducer directly in the path of the
propeller. The transducer can cause cavitation that may
degrade the boat performance and damage the propeller.
Mount the transducer parallel
with the bottom.
Required Tools
(not included)—drill, 3/8" wrench or socket, 5/32" (4 mm) and 1/8" (3.2 mm) drill bits, masking tape, number 2 Phillips
screwdriver, and marine sealant.
To mount the transducer on a transom:
1. Position the transducer mount at the selected transom location. Make sure the transducer is parallel with the water line. Mark the center
locations of each hole on the transducer mount.
2. Using a 5/32" (4 mm) bit, drill the pilot holes approximately 1" (25 mm) deep at the marked locations. To avoid drilling the holes too deep,
wrap a piece of tape around the bit at 1" (25 mm) from the point of the bit.
3. Apply marine sealant to the 5 × 30 mm screws. Attach the transducer assembly to the transom using the 5 × 30 mm screws. Adjust
the transducer assembly to extend beyond the bottom of the transom approximately 1/8" (3 mm) on fiberglass hulls or 3/8" (10 mm) on
aluminum hulls. Adjust the transducer assembly to be aligned parallel with the water.
4. Tighten the 10-32 locking nut until it touches the mounting bracket, and then tighten 1/4 turn more. (Do not overtighten.)
5. Place the first cable clamp on the transducer cable, approximately one third of the distance between the transducer and the top of the
transom.
6. Mark the location. Using a 1/8" (3.2 mm) bit, drill a pilot hole approximately 3/8" (10 mm) deep.
7. Attach the cable clamp using one of the 4 × 12 mm screws. Coat the screw with marine sealant before installation. Repeat steps 5 and 6
using the other cable clamp.
8. Route the transducer cable to the Fishfinder 300C. Do not cut the cable. Avoid routing the cable close to electrical wires or other sources of
electrical interference.
