How to Install a Fishfinder on a Kayak | West Marine

By Mike Montgomery, Tim Clark and Tom Burden, Updated 5/21/2026

West Marine product specialist Mike Montgomery demonstrates a complete fishfinder installation on a West Marine Pompano sit-on-top kayak using the Lowrance Elite-5 TI and Lowrance’s portable kayak kit. The video covers every stage of the process in close-up detail: installing and sealing the track, building and installing the cell block, positioning and installing the transducer arm, installing the battery, and wiring the unit to power. The full installation took about four hours. Before you start your own, read the notes below — the decisions you make before drilling anything determine how well the finished installation works and holds up over time.

Before You Start: What Makes a Kayak Installation Different

Installing a fishfinder on a kayak is fundamentally different from installing one on a powerboat, and the differences matter at every stage. Understanding them before you begin will save you from the most common mistakes.

No dedicated wiring infrastructure. A powerboat has a fuse panel, a 12V circuit, and existing wire runs already in place. A kayak has none of these — you are building the entire electrical system from scratch, starting with the battery. The battery lives in the kayak’s hull, typically in a dedicated cell or storage area, and must be secured so it cannot shift in a capsize. The wiring run from the battery to the display is short — typically 2 to 4 feet — which is an advantage, but every connection must be watertight rather than just weatherproof, because a kayak fishfinder system routinely gets wet in ways a powerboat installation does not.

Track mounting is the foundation of the whole installation. The rail or track system that holds the display mount, transducer arm, and other accessories is the most permanent part of the installation — it is screwed and sealed directly into the kayak hull. Get the track position wrong and everything downstream is compromised. Before drilling, sit in the kayak in your normal fishing position and confirm that the track location puts the display where you can read it without craning your neck, and that the transducer arm will clear your paddle stroke on both sides at its full range of swing. Mark the track position with tape and verify it before picking up the drill.

Sealing every hull penetration is non-negotiable. A kayak hull is a closed flotation system — an unsealed hole in the hull admits water into the hull cavity and over time degrades structural integrity. Every screw hole drilled for the track must be filled with sealant before the fastener is installed. Use a marine-grade waterproof sealant — not standard silicone, which is not rated for prolonged water immersion. Apply sealant to the fastener threads, to the underside of the track where it contacts the hull, and allow it to cure per the manufacturer’s instructions before loading the track with weight.

Transducer placement determines sonar performance. On a sit-on-top kayak, the transducer arm positions the transducer alongside the hull rather than under it, which means it is more exposed to turbulence from paddle strokes and hull movement. Position the transducer forward of the seat rather than behind it — forward placement keeps the transducer in calmer water during paddling strokes. The transducer face must be parallel to the water surface and fully submerged when the kayak is loaded to fishing weight. Test the depth of the transducer with a fully loaded kayak before finalizing the arm position — an under-loaded kayak rides higher and may not give you an accurate picture of where the transducer actually sits at fishing depth.

Battery selection and management matter more on a kayak. A compact sealed lead-acid or lithium battery powers the unit — most kayak fishfinder systems use a 7Ah to 12Ah battery that fits in the hull storage area. Secure the battery so it cannot shift during paddling or in a capsize — a loose battery is both a wiring hazard and a balance hazard. Route the power wires so they cannot be pinched by the battery or snagged on gear. Use marine-grade tinned wire and proper crimp connections — not twisted wire ends and not wire nuts, which fail in a wet environment.

Common Mistakes to Avoid

Not sealing screw holes before installing the track. This is the most common mistake in kayak accessory installation. Drilling an unsealed hole in a rotomolded polyethylene hull allows water to wick into the foam core of a composite hull or simply flood an internal cavity. Apply sealant first, insert the fastener while the sealant is wet, and allow it to cure before putting weight on the track.

Positioning the transducer too far aft. The paddler’s stroke creates turbulence that degrades sonar signal quality when the transducer is directly alongside or aft of the seat. Mounting the transducer arm forward of the cockpit, beside the bow section of the hull, puts it in cleaner water during active paddling.

Using unprotected wire connections. Connections that get wet repeatedly — as all kayak wiring will — corrode faster than in any other marine application. Every crimp connection must be sealed with adhesive-lined heat shrink tubing, and the connection between the power harness and the battery terminals should use proper disconnect terminals rather than bare wire twisted onto a terminal post.

Not testing the system fully loaded before the first fishing trip. Sit in the kayak with all your gear, paddles, tackle, and the fishfinder running, and verify that the transducer is fully submerged, the display reads depth correctly, and the track and mounts are secure. A kayak that rides two inches higher when empty can lift the transducer out of optimal position.

Skill Level Description
Installing the track and caulking: 2 out of 10
Assembling the Portable Kayak Transducer Kit: 5 out of 10
Electrical wiring and connections: 4 out of 10
Tools Required	Shopping List
Installing the Elite-5 TI and the transducer: Cordless Drill Drill Bits Basic screwdrivers, pliers and other common hand tools Utility Knife Striper/Crimper Tool Metric Hex Key Wrenches	Sit-On-Top Kayak Fishfinder/GPS combo unit Waterproof caulk or caulking tape Two female disconnect wiring terminals for the battery connection Scrap Wood for drilling into

Frequently Asked Questions: Installing a Fishfinder on a Kayak

How long does it take to install a fishfinder on a kayak?

A complete installation — track mounting, transducer arm assembly, battery wiring, and fishfinder setup — typically takes three to five hours for a first-time installer. Mike’s installation on the Pompano kayak in the video above took four hours. The most time-consuming steps are planning the track and transducer positions before drilling, and allowing sealant to cure before loading the track. Rushing either step is the most common cause of installation problems that require rework.

Do I need a portable kayak kit or can I use any fishfinder?

Most fishfinder manufacturers offer kayak-specific portable kits that include a transducer arm, battery box, mounting hardware, and wiring harness sized for a kayak installation. These kits are the cleanest and most reliable approach because all components are designed to work together. You can also use a standard fishfinder without the portable kit, but you will need to source or fabricate the transducer mount, battery housing, and cable management separately. For a first installation, a purpose-built kayak kit like the one shown in the video significantly reduces complexity.

Where should the transducer be positioned on a kayak?

Forward of the cockpit, along the hull beside the bow section, in a location where the transducer face is fully submerged at fishing weight and parallel to the water surface. Forward placement keeps the transducer in calmer water during paddling — aft placement subjects it to paddle turbulence that degrades sonar signal quality. Test the transducer depth with a fully loaded kayak before finalizing the arm position, since an unloaded kayak rides higher and may show the transducer as submerged when it will actually be too shallow once you add gear and body weight.

What sealant should I use for track screws on a kayak?

Use a marine-grade waterproof sealant rated for prolonged water immersion — the same 3M 4000 UV or equivalent product used for below-waterline boat hardware. Standard silicone is not rated for constant water exposure and will eventually fail. Apply sealant to the fastener threads and to the underside of the track where it contacts the hull surface before installing each fastener. Allow the sealant to cure per the manufacturer’s instructions before applying load to the track.

What battery should I use to power a kayak fishfinder?

A compact sealed lead-acid or lithium battery in the 7Ah to 12Ah range is the standard choice for a kayak fishfinder. Most fishfinder units draw under 1A at normal operation, so a 7Ah battery provides seven or more hours of continuous use — adequate for a full day of fishing. Lithium batteries offer significantly lighter weight for the same capacity, which matters on a kayak where every pound affects paddling performance. Whatever battery you choose, secure it so it cannot shift during paddling or in a capsize, and use a dedicated battery box or holder rather than leaving it loose in the storage well.

Can I install a fishfinder on any sit-on-top kayak?

Yes, with the right mounting hardware. Any sit-on-top kayak with a flat or near-flat deck surface forward of the cockpit can accommodate a track-mounted fishfinder system. Some newer fishing kayaks have integrated transducer scuppers, built-in rod holders, and pre-routed wiring channels that simplify the installation significantly. If your kayak already has accessory tracks installed, the display mount can often be added without any drilling. If starting from scratch on a bare kayak, the process shown in the video — drilling and sealing a track, then mounting all components to the track — works on virtually any sit-on-top design.

Do-it-Yourself: Installing a Fishfinder on a Kayak