Kayak Fish Finder Guide – 2019

Just because you’ve decided to fish from a kayak, that doesn’t mean you have to go without a fish finder. A portable kayak fish finder is one of the best ways to get into more fish from that ultra versatile vessel.

Many anglers couldn’t imagine fishing without some sort of bottom reader. When finding underwater structure is the only way to find fish, sonar equipment is a must.

If you’ve decided you need a fish finder, installing one on a kayak isn’t difficult.

These days, many kayaks are specifically designed to accommodate fish finders. And if that isn’t enough, some fish finder companies offer product lines specifically geared towards kayaks.

If you’re shopping for a fishfinder for your kayak, here’s a guide to help find the right model and how to install it.

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All About Power

While power consumption isn’t typically a concern for boat fishermen, it’s a critical consideration for kayakers when fish finder shopping.

Lugging around a heavy marine battery on your kayak is not an option. Instead, you’ll need a much smaller, lighter battery as a power source.

You can get away with a light battery if you choose a fish finder that draws minimal power. That typically will mean choosing a unit with a smaller or black-and-white screen.

You can also choose a fish finder with a bigger screen and in color, although you’ll need a bigger battery. Depending on how much power you need, this could add up to 20 extra pounds to your kayak.

There are several battery options. Sealed lead acid (typically AGM) batteries are the most commonly used, as they are easier to find and typically the most affordable. These 12-volt batteries are micro-versions of typical marine batteries. They are rechargeable and have adequate power output for many fish finder models.

To determine how many amp hours your battery needs, you’ll need to find out the power draw for each fish finder. Many companies list that information on their website, although you may need to call the company’s support line if it doesn’t.

This requires a little math, but it isn’t complicated.

For example, say you want a fish finder that draws 200mA and you want to last for a 10-hour fishing trip. You’ll need to multiply the fishing time (10 hours) by the power draw (200 mA), and then divide that answer by 1000.

That figure will be the number of amp hours your battery consumes. You should avoid discharging more than 50 percent of your battery’s total capacity. Doing so can quickly kill your battery and leave you without power on the water.

So for the above fishfinder, you’ll need a battery with at least a 4 amp hour capacity.
Remember this formula for your notes: (Power draw x desired fishing time ) / 1000 = maximum amp hours your battery needs.

To determine the maximum power draw that a specific battery can handle: (Battery amp hours x 1000) / desired fishing time = maximum fish finder power draw.

Some kayakers are now taking advantage of Lithium batteries. These are smaller and lighter, and they aren’t as sensitive to discharging as lead batteries.

These batteries are typically more expensive but will also last longer than a sealed lead acid battery. If you’re looking for a lighter battery, especially if you’re powering a bigger fish finder, this may be the option for you.

Another option is using a group of alkaline batteries. However, this requires frequently buying new batteries. This option will also not provide as much power output, which will limit which fish finder you’ll be able to use.

Most sealed lead batteries come in 7 to 7.5 amp hours capacity. This measurement is important to know when choosing a fishfinder, as it will allow you to calculate how long your battery will power the unit.

Once you’ve decided on a power source, you can pick the fish finder.

There are several factors that you’ll want to consider.

How much functionality do you need?

If you’re simply a weekend warrior or on a tight budget, you may be looking for a basic unit that will find underwater structure and depth. But if you’re a diehard or building your dream kayak, you may be looking for the latest in sonar technology.

GPS-capability is another consideration. There are several fishfinders that have built-in GPS units. If you don’t already have a handheld GPS, you should consider choosing a fish finder/GPS combo. There are several compact, kayak-friendly options.

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Screen size

Smaller screens take up less power than larger ones. So do black-and-white screens compared to color versions. Many kayakers are happy with a 3 or 4-inch version. They take up less room in your cockpit and require smaller batteries.

If that’s not enough, a 5-inch of 7-inch screen is probably the biggest you’ll want to go. Anything bigger than that may be difficult to power for longer trips.

Transducer

The transducer is the puck-like device that sends sonar signals through the water. Proper installation of the transducer is critical for optimum performance.

Several kayak models are equipped with special transducer mounting options. If you have these kayaks, it may be easier to choose a fish finder that comes with a transducer that’s compatible with your kayak.

If your kayak doesn’t have that feature, don’t worry. There are several easy ways to install your transducer.

Some companies offer transducers that can be easily mounted through your kayak’s scupper holes. If you fish on a sit-on-top kayak, you should consider this option. The installation is as easy as dropping the transducer in a hole. It requires no glue or drilling, and it can be easily removed for transportation or when paddling through shallow or rocky water.

If your kayak has mounting rails, you can also purchase a special transducer arm. These arms are mounted to the rails and extend into the water. You simply attach the transducer to the end of the arm.

If your kayak doesn’t contain either of these features, you still have several options that aren’t too difficult.

You can use a through-mount transducer if you have access to the inside of your kayak. You can also attach a plate to the back of your kayak with epoxy. Then, attach the transducer with screws, just like you would on a normal boat.

Here’s a detailed guide to both of these installation methods.

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Our Favorite Kayak Fish Finder Options

Garmin Striker 4cv

With a 3.5-inch color screen, state-of-the-art sonar technology and a built-in GPS unit, the Garmin Striker offers a lot in a small package – and under $200.

This fish finder is equipped with Garmin’s multi-frequency Chirp sonar for pinpointing fish and bait, as well as its ClearVu Chirp sonar, which provides highly detailed images of what’s underneath.

It also has a sensitive GPS machine that allows anglers to save fishing spots for future trips. You also mark and save your trip’s path for easy navigation. It will also tell you how far you’ve paddled, which is a neat feature that’s great for kayakers.

The unit draws 400 mA of power, which is entirely suitable for use on a kayak.

Lowrance Hook 3x

If you’re looking for a simple fishfinder for under $100, consider the Lowrance Hook3x.

The unit comes equipped with a 3-inch color screen and dual-frequency sonar capability for versatility. This simple unit doesn’t take much power, so it will be easily powered by any kayak battery.

Lowrance offers a full-line of kayak-compatible transducers, including the scupper-mounted transducer that is compatible with virtually every sit-on-top kayak.

In terms of affordability, function and simple installation, this is a great pick.

Lowrance Hook 5:

If you’re a serious angler who wants a kayak that can hang with the power boats, consider the Hook 7.

This model is also compatible with Lowrance’s line up of kayak-specific transducers, so installation will still be a breeze.

This fish finder will turn your kayak into an absolute fishing machine. It comes with a 7-inch color screen, powerful Chirp sonar and Lowrance’s Down Scan imaging for highly-detailed images of the bottom.

It also comes with a GPS and chartplotter. The unit also allows you to upload highly detailed maps of lakes, rivers, and oceans.

This fish finder draws 1100 mA. That gives you about 6.8 hours of life with a 7.5 amp hour battery.

That isn’t optimal, but if you need the features included here, consider installing a backup battery for extended life.

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Kayak Fish Finder Accessories

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Scotty Transducer Arm

If you decide to purchase a fishfinder that isn’t kayak compatible but still want an easy installation, the Scotty transducer arm is for you.

The arm can either mount to your kayak’s mountain rails or can be screwed into the hull. The arm extends into the water. Simply mount your transducer at the end of the arm, and you’re ready to fish.

Hobie 12v fish finder battery

This rechargeable battery weighs just four pounds and offers 7 amp hours of juice. It was designed specifically for kayakers and is compatible with Hobie’s kayak fish finder products.

Ram Mount Fishfinder System

If you’re looking for versatility… check out Ram Mount. They make myriad mounts for a variety of devices. They assemble like your childhood plastic building blocks and adjust like no other. Plus they’re insanely stout. The centerpiece of the design is a rubber-coated ball and from there

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