Side scanning, down scanning, front-view, CHIRP, megahertz and watts—you need to be a rocket scientist to use a fish finder, right? Not true. The latest generation of fish finders pack a ton of features in small packages, and many boats are pre-rigged with transducer scuppers and battery compartments to make installation a breeze.

Types of Kayak Fish Finders

Down Scanning

Shoots a high-frequency, narrow-beam signal to create a photo-like image of the bottom. Offers incredible detail of structure and vegetation.

Side Scanning

Uses the same signal as down scanning sonar, but shoots to the side to create an image of bottom, structure and fish to the left and right of the kayak. Recently available in forward- and 360-degree scan.

[ See also: Why You Need To Add Side-Imaging Sonar To Your Fishing Kayak ]


Transducer emits sonar signals on two frequencies to create a detailed image of structure and fish. Provides improved target separation. Best for deep water.

How to Install a Fish Finder on a Kayak

On most kayaks, installing a fish finder comes down to three simple steps.

1 Mount the Display

The most important piece of the electronic system, the display unit should be placed in reach but out of the way. Displays come in a variety of sizes from three inches to more than 12 inches. If you are just running a depth finder, then a four-inch display will suffice, but most anglers are going for GPS and fish finder combo units, which run on split screens, making five- to seven-inch displays easiest to read.

Picking a place to mount a display is a tough choice. Modern fishing kayaks are designed with flat areas and preinstalled gear tracks in popular locations for placing displays. Many anglers choose to install displays using adjustable arms on gear track bases.

Use an adjustable arm on a gear track to change the location of the display and quickly remove it at the end of the day. A larger display may require a permanently mounted base attached with four stainless steel bolts and matching lock nuts. Place a dab of silicone around the bolt hole before tightening the nut.

Pedal kayakers often install displays on gear tracks on the gunwales and close to the seat. Paddlers want the display out of the way in the center of the kayak, forward of the cockpit.

Wherever you install the display, remember you’ll have to run wires to the transducer and battery. Placing the display near a deck hatch or scupper may make install easier.

2 Place the Battery

Heavy batteries are the only real downer to adding electronics. Powering a fish finder display calls for at least a 10 amp hour, sealed lead acid or lithium ion battery. Sealed lead acid batteries are heavier but cheaper. Lithium ion costs more but lasts longer and weighs less.

Placement of the battery in the kayak is a crucial decision. For the best weight distribution, set the battery inside the hull, near the seat and along the centerline.

Run the wire through a hatch. If that’s not possible, use a through-hull grommet to thread the wire to the battery.

To keep the battery dry and secure, use an approved battery box with foam padding and sealed connections. Without a battery box, use a piece of closed cell foam, such as a garden mat available at a lawn and garden store. Trace the battery on the mat and cut out the shape. Use silicone to glue the foam to the bottom of the hull. Place the battery in the pocket. For a more secure fit, layer two pieces of foam to create a deeper pocket.

Convenience is the most important consideration when installing electronics. The display unit should be easy to see and operate. The wires should not get in the way. The battery must be secure and easy to reach. And the whole system has to be quick to install and remove.

fish finder mounted on a fishing kayak
A clean install is easy to operate. | Photo: Scott Beutjer

3 Install the Transducer

Transducer arm used for installing kayak fish finders

Installing the transducer and running the cable to the display has always been the most frustrating part of adding electronics. No one wants to drill extra holes in a kayak. Fishing kayak manufacturers have come up with innovative scuppers, wells and pods to hold transducers.

Some kayaks are designed with special scuppers to accommodate the transducer and cable. Some anglers choose to install the transducer inside the kayak so the signal shoots through the hull. This requires carving a foam dam and filling it with gobs of silicone. The system rarely works well.

Many anglers install their display, battery and transducer on a special base fitting in a gunwale gear track. The base holds the display and battery with an arm dangling the transducer over the side of the kayak. Housing the display, wires, battery and transducer on a removable mount is convenient. The system is also popular for the latest generation of fish finders offering forward seeing sonar.

It’s best to install the transducer ahead of the cockpit, where it won’t be affected by pedal or paddle turbulence. Try to keep the bottom of the transducer flush with the bottom of the kayak.

Video Review of the Lowrance Transducer Kayak Scupper Mount:

How to Read a Fish Finder

Fish finder basics are easy to learn. Most units are user-friendly—just turn it on and go fishing. However, some anglers will want to adjust gain, speed, colors and other settings for optimal performance. On a fish finder, gain controls the sensitivity of the receiver. Speed is how fast the sonar images pass on the screen. Adjust the color contrast for the best definition. Adjusting depth or using a split screen will zoom in on a specific area of the image.

For more in-depth instructions on how to read a kayak fish finder, including more details on all of the above settings, see our article on How To Effectively Use A Fish Finder.

A man on a fishing kayak using a fish finder from Garmin
Nothing helps you find more fish than a kayak fish finder. | Feature photo: Courtesy of Garmin

Best Fish Finders for Kayaks

With recent advances in side scanning and 360-degree imaging technology, the state of the art is always advancing for manufacturers of kayak fish finders and sonars. We round up the top performers and best value models from recent years in Kayak Angler gear reviews.

Fish Finder Reviews

This article was first published in the Summer 2019 issue of Kayak Angler Magazine. Subscribe to Kayak Angler Magazine’s print and digital editions, or browse the archives.

Nothing helps you find more fish than a kayak fish finder. | Feature photo: Courtesy of Garmin



Please enter your comment!
Please enter your name here