DIY Fish Finder Install on a Jon Boat

Jon boats are the workhorses of inland fishing — simple, stable, affordable, and tough enough to handle river shoals, shallow flats, and back-country launches that would swallow a bass boat. Adding a fish finder transforms a basic jon boat from a floating casting platform into a capable fishing machine with sonar, GPS, and depth information at your fingertips.

The installation is straightforward. Most anglers can complete a basic fish finder install on a jon boat in an afternoon with basic hand tools. This guide walks you through every step, from choosing where to mount the display to wiring the battery and positioning the transducer for optimal performance on an aluminum hull.

What You'll Need

For a basic jon boat fish finder installation, gather these materials before you start: your fish finder unit with included transducer and mounting hardware, a dedicated 12V battery (AGM or lithium, 12-50 Ah depending on your unit), marine-grade 14 AWG or 12 AWG tinned wire (red and black, 10-15 feet each), an inline fuse holder with a 3-5 amp fuse, ring terminals and butt connectors (marine-grade with adhesive heat shrink), a battery box or tray, and zip ties or cable clips for routing.

Tools needed include a drill with assorted bits, a screwdriver set, wire strippers/crimpers, a tape measure, and marine sealant (3M 4200 or equivalent) for any holes drilled through the hull. If you're mounting the display on a RAM mount, you may also need the appropriate RAM ball and arm components.

Step 1: Plan Your Layout

Before you drill anything, sit in your normal fishing position and visualize where you want the display, where the transducer will go, how the cables will route between them, and where the battery will live.

On most jon boats, the fish finder display mounts on the front bench seat, on a crossbar, or on a pedestal near the bow where you do most of your fishing. The transom gets the transducer. The battery sits on the floor near the display or in a storage compartment if your boat has one. The cable routes from the transom forward along one side of the hull, secured to the gunwale or floor with clips.

Avoid mounting the display where it will be in the way during casting or where the sun will hit the screen directly all day. A position slightly offset to the port or starboard side of center, angled toward your primary fishing position, is ideal.

Step 2: Mount the Transducer

The transducer is the most critical installation decision. On a jon boat, you have two primary options: transom mount or trolling motor mount.

Transom Mount

Most fish finder packages include a transom-mount bracket. On an aluminum jon boat, position the transducer on the transom at least 6 inches away from the outboard motor's lower unit — engine turbulence creates air bubbles that interfere with sonar. The bottom of the transducer should be level with or slightly below the hull bottom so it gets clean water flow at all speeds.

Drill pilot holes for the mounting screws, apply marine sealant (3M 4200 or equivalent) to each screw before driving it, and tighten snugly but don't overtorque — aluminum strips easily. The sealant prevents water intrusion through the screw holes. Allow 24 hours for the sealant to cure before launching.

On aluminum hulls specifically, place a rubber vibration pad or marine adhesive pad between the transducer bracket and the hull. Aluminum transmits vibration and engine noise more directly than fiberglass, and this dampening pad reduces sonar interference significantly.

Trolling Motor Mount

If your jon boat has a bow-mount trolling motor, many transducers can be mounted on the motor shaft or lower unit using aftermarket brackets. This puts the transducer in clean water ahead of the hull — ideal for sonar performance at low speeds — but the cable run is longer and more exposed. Secure the cable to the trolling motor shaft with spiral wrap, leaving enough slack for the motor to turn and deploy/stow without straining the cable.

Step 3: Mount the Display

Popular mounting approaches for jon boats include tilt-and-swivel brackets on the front bench, RAM mount systems that attach to seat rails or gunwales, and portable mounting solutions that let you remove the display after each trip.

If you drill into the boat for a fixed bracket, seal every hole with marine sealant. Aluminum jon boats don't have an inner liner to hide wiring, so plan your cable routing to be neat and secure — exposed wires snag on tackle and feet.

For anglers who share the boat or want to remove electronics between trips, a portable battery-powered setup with a RAM mount quick-release allows you to take the entire system on and off in minutes.

Step 4: Wire the Battery

Run your power wires from the battery to the fish finder's power cable. Use 14 AWG marine-grade tinned wire for runs under 10 feet; step up to 12 AWG for longer runs. Connect the inline fuse holder to the positive (red) wire within 6 inches of the battery terminal — this protects against short circuits.

Use marine-grade crimp connectors with adhesive-lined heat shrink. Solder connections are acceptable but crimp connections with quality terminals are often more reliable in the vibrating, moisture-prone marine environment. Connect ring terminals to the battery posts and hand-tighten the battery terminal nuts.

Route the power wires along the same path as your transducer cable but keep them separated by at least 3 inches to avoid electrical interference. Secure both runs to the hull with adhesive cable clips or zip ties every 12-18 inches.

Step 5: Test Before You Launch

Power on the fish finder and verify the display works, the transducer is recognized, and GPS acquires a signal (if equipped). You can't test sonar returns on dry land, but you can confirm the system is wired correctly and all connections are solid.

On your first trip, run the boat at low speed and check the sonar display for excessive noise, intermittent bottom loss, or blank spots. If the display is clean at idle but noisy at speed, the transducer is likely getting turbulent water — adjust the mounting height or angle. If the display is noisy at all speeds, check for wiring interference from power cables running too close to the transducer cable.