How To Mount a Fishfinder 101: In-Depth Guide and FAQs 2021

Lance Wilkins
Lance Wilkins
Editor @ CallOutdoors. Outdoor gear-head and adventure addict. I fish, camp and enjoy to writing about my adventures.

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So you’ve done all that hard research to find the best performance fishfinder for your fishing boat, and now you need to mount it.

Fish finder mounts differ and the worst thing you can do is go in guns blazing and mount it incorrectly, as there will be a never-ending list of jobs to do in order to correct it.

Plus, if you don’t get it right, the fishfinder might not even work as it’s supposed to.

Think it Through

Mounting your fishfinder is quite a serious project so if you’re not sure that you’re the best person for the job, there are loads of people that are experts in marine electronics installation that it might be a good idea to outsource the installation to.

No matter how excited you are to use your new fishfinder, take a deep breath and mount it properly by following the installation instructions we discuss in this article…

Mounting A Fishfinder

Fishfinder, Rods, and Tools at the Back of a Boat
Fishfinder, Rods, and Tools at the Back of a Boat

Before we get into the details of how to mount your fishfinder, let’s take a step back and look at the bigger picture so you have a general understanding of what needs to happen.

The Parts

A fishfinder comes with two main parts: the control head unit which is the display and the transducer.

Along with these, you’ll also have the transducer mounts, the brackets for the display plus transducer wires, and power cables.

The Idea

The idea behind the installation is to make sure that you can use your fishfinder comfortably and that it works as effectively as possible.

There are 4 main things you’ll need to do for this to happen.

  • Mount your fish finder display in a location where you can see it comfortably while driving your boat.
  • Mount your transducer in the location where it gets the best readings
  • Connect the transducer cables to the fishfinder display so the transducer readings come through
  • Connect the power cables to the fishfinder to a battery.

NOTE

It sounds like an easy task but there are loads of options and different mounts and brackets to choose from, each requiring some technical manual labor.

The Things You’ll Need To Mount Your FishFinder

Before you start your installation make sure you have everything you need first.

There is nothing more frustrating and time-wasting than finding out you don’t have everything needed and having to run to the supply stall mid-installation.

Fish Tape

Fish tape is bendy flat steel that is flexible enough to be threaded in and out of the wiring channels that the transducer wires and power cable will run through.

You’ll be able to run the fish tape through the channels from the battery power source and transducer and back to the unit.

Simply attach the cable to it with masking tape and thread it back through.

Gloves

Gloves are a must when doing a fish finder installation as they will protect you from fiberglass cuts when you’re drilling holes or putting your hands under the deck.

Cordless Drill & Drill Bit

You’ll be drilling a pilot hole for the transducer mounting and the fishfinder display mounting so a powerful drill and a sharp drill bit is a must.

Masking Tape

Electrical Tape by Jonas Bergsten
Electrical Tape by Jonas Bergsten

When drilling into fiberglass you should put some masking tape over the drilling area.

This will stop the gel coat from cracking when the drill bites into your hull.

Cable Ties

Cable ties are the best tools to use to ensure your install looks good.

You’ll need quite a few of them, say 50 plus, to wrap around all the cabling so it’s neat and tidy.

Electrical Tape & Shrink Tubing

You might have to splice two wires together to get the right length you need when installing a fishfinder on your boat, and the neatest way to secure the splice is with shrink tubing.

Once the splice is done and tested, pull some shrink tubing over it and seal with a heat gun. You can also use electrical tape but it’s not as neat.

Heat Gun

Once your fishfinder is wired up, you’ll need a heat gun to shrink the tubing over the wires splices as mentioned above.

Be careful when using the heat gun and don’t let it point at the gel coat or the boat carpet as it can easily burn or discolor it.

Fuse Kit & Inline Fuse Holder

All models of fish finders, no matter the brands, have to use an inline fuse to protect the fish finder from any current or voltage spikes from the battery.

You’ll have to connect the fish finder via the fuse box and/or a fuse you install, to the battery for it to be protected from any battery power surges.

Wire Stripper & Crimper

You’ll need a wire stripper and crimper to be able to splice and secure wired connections when installing your fishfinder on your boat.

Fish Finder Mount

Whichever mount you opt to go with for your fish finder, make sure you have all the parts needed.

If you decide on a flush mount, you’re likely to need the flush mount accessory kit from the manufacturer.

Transom Saver Block

If you’re installing a transom mount transducer, having a block to put your transom mounts on is your best plan.

Here’s a short video to give an idea…

Transom Block installed & Foam Test results!!

The transom mount saver block is where you’ll mount your transducer, but the great thing about it is that you only have to drill holes in your boat once, to mount the block, and after that you can move your transducer around as much as you’d like.

NOTE

Also, if for some reason the transducer gets pulled off accidentally, you’re not going to have a hole in your transom, as the block will be pulled off instead.

Where Should You Mount Your Fishfinder Display?

Fishfinder Near Boat Steering Wheel
Fishfinder Near Boat Steering Wheel

It’s best to mount your fish finder display in the location where you drive your boat or paddle your kayak from. The reason for this is that the fish finder is not just showing you sonar readings, and will often be your GPS and chartplotter too.

Bass Boat

If you use a trolling motor on a bass boat, for example, you might want the location of the fish finder to be at the bow next to the trolling motor controls.

Whereas if you use a center console with an outboard, near the steering wheel is the best location for it.

Placement

To use it effectively you’ll want it to be easy to see from your steering wheel or trolling motor controls so you can change course quickly, or stop the boat when you see a good fishing spot on the sonar.

TIP

Just make sure there is enough space for the type of mounting you choose and that you can see it properly.

Height, Fuses & Binnacle Mount

Your best plan is for the fishfinder to be mounted in a location that is between the height of your waist and shoulders.

Lower or higher than this, and you’ll be straining your neck and back to see it.

You should also check where the nearest fuse box is, as you’ll be running the power cable there.

Once you’re done all this, take the binnacle mount and place it around your console in your desired install area to know it’ll fit.

For those that don’t know, the binnacle mount is the part of the fishfinder mount that attaches to the boat.

Tips For Console Installation & Fish Finder Mounts

Man Casting a Rod While on a Boat

Flush/In-Dash Mount

A flush or in-dash mount means the fish finder display will be installed into your console or bridge and won’t be sticking out at all.

A flush-mounted fish finder looks a lot better than having it sticking out of the console and it protects the rear connections from corrosion as they are sealed in the console.

There are some downsides though.

Disadvantage

You won’t be able to take the fishfinder home with you, as once it’s flush-mounted it stays in the boat, and it takes up a lot of console space.

This means it could get stolen, you can’t turn it for a different viewing angle, and you can’t take it home for software updates so you’ll have to use an SD card for that instead.

Plus each cable that goes into the back will be hidden, so wiring it up will be more difficult.

Gimbal Mounted

Putting your fish finder on a gimbal mount means it’ll be sitting on the dash on its own mount rather than in the dash like with a flush mount.

They are smaller and you can mount them in more places, like high above the steering wheel.

Fishfinder Mounted at the Back of a Boat
Fishfinder Mounted at the Back of a Boat

Portable

You’ll be able to take the fishfinder home each day, have easy access to the cable ports at the back, and it’ll swivel so you can turn the display to find your optimal viewing angle.

The downside is that the cable ports will be exposed to any splashes, rain, and salty conditions and so could suffer from corrosion.

RAM/Kong/3rd Party

If you need to be able to move our fishfinder location around, you’ll want to go with a 3rd party mount.

As long as you have a flat area to screw the base into, you can pretty much install a Kong or RAM mount anywhere.

Advantage

You’ll be able to install the fishfinder display anywhere like above the steering wheel, save space, and still be able to take it home every day for security and software updates.

The downside is that RAM mounts tend to fail under heavy conditions, so aren’t the best for rough water.

The cable connections will also be exposed to the elements, risking corrosion.

Tips For Bow Installation Of Fish Finders

Man on a Boat Fishing on a Lake
Man on a Boat Fishing on a Lake

If you want to install your fish finders at the bow next to your trolling motor, you have a few good options.

Picking the right one comes down to having enough space on your boat, and if you want to spend a little extra on mounting your fish finder.

Flush Mount

On some boats, there is an angled panel on the bow where you can flush mount your fish finder.

Flush mounting has the same pros and cons I mentioned above in the console section but on the bow, you have an added con.

The fish finder will be low down and further away than if you used the other mounting options below, making it a little harder to see.

Gimbal Mount

Gimbal mounting on the bow brings the fish finder higher up for easier view, and you can change the angle to suit you.

But it does take up deck space and can cause tangles with your rods.

The gimbal-mounted fish finder can also get in the way of the foot pedals you use to control your trolling motor if they are not recessed.

RAM/Kong/3rd Party

RAM/Kong/3rd Party Mounts are a great option if your trolling motor pedals are not recessed as you can mount them on the bow or gunnel and still swing them into view and change the angle so you can see your fish finder easily.

Bridge Mount

A bridge mount creates a raised bridge over your trolling motor pedals using a bracket.

It’s a raised bracket that is high enough for your feet to get under and control your trolling motor while also raising your fish finder for better viewing and takes up less space on the deck.

Bracket

You can make the bracket yourself if you have some bracket-making skills, or buy a 3rd part bracket.

Bracket brands like Wave Tamer or Dek-It make an excellent fish finder bracket for bow installation and you can choose your bracket color too.

Where Do You Mount A Transducer?

Man Sitting in a Docked Boat
Man Sitting in a Docked Boat

Transducer location comes down to the type of transducer you have and there are three categories to choose from: trolling motor/transom mount, in-hull, or a thru-hull transducer.

You’re most likely to have a transom mount transducer if you have a boat under 27ft with outboard engines.

TIP

If you own a large boat with inboard engines, you’re best off with a thru-hull transducer as an in-hull takes poorer readings, and the wash from your engines will reduce the readings of transom mount transducers.

Transom Mount Transducers

Transom mount transducers go on your transom or trolling motor, an in-hull will sit above the hull, and thru-hull transducers will be poking out of a hole cut in your hull so it’s fully covered in water.

Always read the manual when it comes to transducer mounts, types, and installation, as the exact requirements will be in there for best performance.

NOTE

You should also think about the transducer wire, as you’ll have to make a hole wherever you place it for the transducer wire to run back to the fish finder control head unit.

Where do you mount a side imaging transducer?

Transducer location also comes down to whether your transducer is a side imaging transducer.

This type of transducer comes with transom mounts, so you’ll place it the same way you would any normal transom transducer mount.

Do transducers have to be in the water to work?

Man Preparing To Catch A Fish with a Net
Man Preparing To Catch A Fish with a Net

This depends on the type of transducers you’re talking about.

Transom mounts, trolling motor, and a thru-hull transducer have to be fully submerged so their signals aren’t blocked by any hard substances.

An in-hull transducer doesn’t have to be mounted in the water and is designed to sit against the hull and transmit signals through it.

How do you level a transducer?

If you’re using a transom transducer mount, you’re going to need to level your transducer for optimal imaging.

This involves ensuring the transducer is leveled when compared to the boat at your desired fishing speed, usually 4-5 knots so it gives you the best readings possible.

To level your transducer you’ll need a spirit level, some coins, have your boat on the trailer, and follow these steps.

  • To begin, tighten up your transducer so it’s leveled on the spirit level out of the water.
  • Now, launch your boat and take it for a drive at 4-5 knots with your fish finder on.
  • If you’re seeing arcs angled more in either direction on your fish finder, the transducer is not leveled perfectly.
  • If you have side imaging, drive along the side of a bank and see if the side is straight on your unit display, if not there is an error with the leveling.
  • To fix it, take your spirit level and place it on the gunnel of your boat while going at your fishing speed.
  • Raise the stern end of the spirit level by adding coins until the spirit level is leveled.
  • Take those coins and put them aside, not mixing them up with anything, as you’ll need them later.
  • Take your boat back to the ramp, put it on the trailer, and drive it to a level surface.
  • Place the spirit level on the same part of the gunnel again with the coins
  • Jack up your trailer until the spirit level is leveled. You may need to add some blocks to raise it depending on the trailer you have.
  • Once leveled, loosen your transducer on the transom mount so you can move it around.
  • Now take the spirit level and put it flush to the bottom of the transducer, and tilt the transducer until the spirit level is leveled.
  • Once leveled, tighten your transducer, making sure it remains level as you go (it’s likely to try and raise when being tightened)
  • Now, launch your boat and test the fish finder. It should work the first time, but if not, repeat the steps above.

Tips on How to Install Your Transducer

Group of Fisherman on a Boat
Group of Fisherman on a Boat

A lot of people will not read the manual for one reason on another, install their fish finder unit, hook it up to the battery, test it on the water and the unit doesn’t work.

This one type of behavior can cause a fish finder to get a bad name when actually it was the customer who didn’t read the manual on how to install their unit properly.

If there is one thing you should do with any kind of electronics, it’s read the manual.

Once you have read the manual and found the right place for your transducer, read these tips on how best to install it.

Transducer Shield & Saver

If installing your unit on a transom it’s highly recommended to install a transducer shield and saver. It’s a spring back bracket that you attach to your transom so that if you do hit anything it springs back saving your unit from being damaged.

Stern Saver Block

When transom mounting your unit you can also opt to use a stern saver block. It’s a polyethylene block that you screw or epoxy to your transom that you then attach the transducer unit to.

Using a block like this means you only have to drill holes in your boat one time and you can then move the transducer unit around as much as you like without making any new holes.

Fiberglass Hulls

When installing your unit on fiberglass hulls make sure you’re not installing anywhere near obstructions like intakes, sensors, jack plates, and motors.

Once you have found your spot, mark it out with masking tape and drill through the tape so as not to chip the gel coat.

Aluminum Hulls

The same tips apply to installing a transducer on an aluminum boat but there is an extra thing to be aware of.

Aluminum hulls are welded and riveted and these bits cause water turbulence that will affect your sonar image.

Be sure to avoid lining up any of those joints with your transducer.

Trolling Motor

Mounting a unit onto your trolling motor is about as easy as it gets.

All it requires is an adapter bracket or kit with a base mounting for the transducer.

All you do is attach the transducer to the mounting, slide over the adopted bracket onto the front end of the motor and tighten.

Mounting a Fish Finder on to a Kayak

Fishing Rod at the Side of a Kayak
Fishing Rod at the Side of a Kayak

If you’re into kayak fishing you’ll probably want a fish finder on your kayak. Installing one on a kayak is pretty much the same as on a boat but you’ll find different mounting options will work better.

Here are some tips for how to do it best…

Control Unit Installation Tips

  • Pick a good place for the display so you can see and use it easily where you paddle and fish from
  • Think about battery placement and battery cables when placing your display as you’ll have to run cables to it for power.
  • Make sure the battery is in a dry bag or waterproof housing
  • Use a gimbal or RAM mounting so you don’t take up too much space, change the viewing angle, and so that you can take your fish finder home with you for security.

Transducer Installation Tips

Where you put your unit comes down to, again, the type of unit you’re using.

When it comes to kayaks the best type and the most likely one you’ll use is a transom-mounted unit.

You can attach one of these to a trolling motor if you use one or to an arm that hangs over your kayak and into the water.

The benefits are that you can take your unit home, making it fully portable and safe from theft.

Plus you can move it around the kayak if you need to,

  • Think about unit placement in relation to the display as you’ll have to run wires between them
  • Pick the right mounting option for you, the best choices are either on your trolling motor or on an arm as mentioned above.
  • Make sure your unit is leveled for the best readings by following the instructions in the sections above

Sounding Out

You now know how to install a fish finder on your boat.

The key is to read the manual, have all the tools and parts you need before you begin, and then take it slowly.

Plus, it’s never a bad idea to ask for a professional’s help if you need it.

A poor install will give you headaches for years, so get it right the first time.

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Lance Wilkins
Lance Wilkins
Editor @ CallOutdoors. Outdoor gear-head and adventure addict. I fish, camp and enjoy to writing about my adventures.
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