How to Install a Fish Finder

How to Install a Fishfinder
Fishfinder Installation Ken McBroom

Fish Finder Installation

  1. Location, location, location. Before you even start your fish finder installation choose a location that best serves your purpose.
  2. Transducer installation. Transducer location is vital for optimum readings below the surface. Thru hull, trolling motor and Transom
  3. Running the wire. This can be the most challenging of the fish finder install. Here is some tips to help you.
  4. Termination of wires. One of the most important steps in a complete and lasting fish finder installation is the quality of wire termination.
  5. Mount the fishfinder. Be sure to mount your fish finder in a way that holds up to the rigors of fishing trips and rough water. 
  6. Wrap it all up. Clean up all the wiring and terminations. Go one step further to eliminate broken wire and corroded terminals.

Mounting Locations

The first step in how to install a fish finder whether installed on a kayak, bass boat or cruiser is figuring out where you want the fishfinder to be. There’s nothing worse than getting everything installed and learning that it just won’t work there.

When locating your fish finder, place it in the spot you like and actually sit in the boat or kayak or stand at your helm and move the fish finder around on your swivel mount. Make sure that nothing is in the way visually or physically. If you need the unit to turn 180 degrees to use it the way you want to then rotate it throughout the range you need it to move and make sure it will do it. Also be sure to use the complete fish finder when determining location. Oftentimes your new fish finder will have a cradle that it fits into for installation.

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Use All The Pieces When Locating Your Fish Finder

Be sure to put the fish finder inside the cradle or any other mounting brackets or mounts that come with your unit. I have installed many fish finders and it only took a couple times not including the entire mounting package in the location process before I learned my lesson. What happens is you determine that your sonar fits where you want it and it rotates fine clearing the steering wheel or the hull fine then when you get ready to mount it inside the unit’s cradle you find that that little bit of extra width or height will not allow it to move to where you need it. If you are installing a ram mount for your fish finder installation make sure you include it in when you are determining your fish finder location. Trust me, you will thank me for this tip.

How To Mark The Spot for Installing Fish Finder

This should go without saying. Marking your location exactly is important. You took all that time testing the location where your fish finder will function the way you want only to come back 2 hours later and not know for sure where that spot was, exactly.

Many times a fish finder fits where you want it but barely. When your unit is rotating within a 1/4 of an inch clearance of whatever is in the way you don’t have much room for error. By marking the spot exactly while you have the unit in position and know it will work there you save yourself the time and frustration of doing it all over again when you are ready to drill your fish finder mounting holes for installation.

Locate The Spot For Fish Finder Transducer Mount

When you have the location picked and marked for the mount or brackets the next step is to locate the position location of your transducer mount. There are several different types of transducer mounts and I will go over the most common fish finder transducers for fishing boats. Each transducer mounts differently.

Trolling Motor Transducer Mount

If your fishfinder installation will be on the bow a trolling motor transducer mount or bracket is used. This allows you to see below the bow of your boat with your fish finder and can even help you locate fish and cover while in the front of the boat. You can connect your transom mounted transducer to the fish finder installed on the bow but that is networking and would need an entire article to cover that topic. This article will stay focused on the most common installations among anglers.

There are now several different transducers made for mounting on the trolling motor. There are simple puck style trolling motor transducers that are contoured to fit the trolling motor housing and can be attached with just a large hose clamp. This clamp should be stainless so it doesn’t rust. Don’t skimp on the hose clamp for your trolling motor transducer.

There is also a transom mount for trolling motor bracket that allows you to attach a common transom mount transducer to your trolling motor. I will explain the skimmer transducer later in this article when we talk about the transom-mounted transducers. The only real advantage to the skimmer transducer on the trolling motor is cost. The skimmer transducers cost a little less than the low profile and small puck style transducers mentioned above. The disadvantage to the skimmer transducer on the trolling motor is the fact that it sticks down further catching on rocks and stumps etc… much easier and is more susceptible to breakage or misalignment. If you fish hard in shallow water like me the puck-style transducer is the only way to go for a down imaging fish finder on the bow.

If you use a side-imaging fish finder on the bow and use the trolling motor for the transducer location then a special bracket is available to help protect your expensive side imaging transducer. Again, you can network or run your transducer wire from the transom all the way to the fish finder in the bow. However, anglers want to see what’s underneath them and will mount the transducer mount bracket on the trolling motor.

Trolling Motor Transducer Mount

Transom Mount Transducer

The transom mount transducer is a common installation for fishing boats. It is simple yet effective in providing water temperature. These transducers are referred to as skimmer transducers. They are standard equipment with most fish finders. These transducers are pretty straightforward forward and installation can be completed before running the wire. The transducer wires are attached to the transducer and the end has the screw on connector. It can be more difficult to run. Especially when going through the existing conduit and/or zip ties. This is where the wire snake comes in handy. Run it on the outside of all factory wire so you have enough space to pull it through.

Wiring Tip: Never cut a transducer wire. The transducer is calibrated to the length of wire and the resistance of that wire. If you cut it and connect it back at the same length these connection points are susceptible to corrosion. The fish finder can’t handle any kind of anomalies that would occur with even a tiny amount of corrosion. It is best to never cut the transducer wires.

Side Imaging Transducer

Side imaging is a great tool for the angler. It can see to the side of the boat and locate fish and cover quicker than ever before. This technology requires a larger transducer to see all that and it’s usually mounted on the transom. It can be mounted on the trolling motor. Most people mount it on the transom.

Follow the provided instructions when installing your transom mounted side imaging transducer. Keep in mind the transducer sends a signal out both sides and downward so make sure you mount it where there is no obstruction to these signal. Also keep in mind the void created by the boat hull. The transducer has to be completely submerged to work. When the boat is idling along it can push a lot of water and this can leave the side imaging transducer on the transom out of the water and give you bad readings.

side imaging transducer installation
Side Imaging Transducer Installation Ken McBroom

Transducer Tip: Make sure the transducer clears the trailer bunk when set at the proper angle.

Thru Hull Transducer

A thru-hull transducer is a great thing. It mounts in the bilge against the hull and shoots signals thru the hull. This application keeps your transducer safe from hitting anything, it is completely protected inside the hull. The thru-hull transducer is more expensive than the other options but is a great option for many applications. There is even a side imaging thru-hull transducer available.


Running Wires for Fish Finder

Running wires for your fish finder is probably the hardest thing to do when doing a fish finder installation. Not all boats are created equal when it comes to running wires for a fish finder. Here are a few tips to hopefully make it a little smoother.

Get a snake for running wires. A snake is a long slick and flexible cable that you can attach your fish finder wires to. A wire snake is used to pull or push them through to their destination. You can run the wire snake up to where you plan to terminate the wires then attach wires. Now you can pull them through. The snake can keep you from having to remove panels and control quadrants. Sometimes you still have to remove those to get the wires ran.

Wiring Tip: I try to add a couple extra wires to the wires I am running. This is so you have a couple extra wires later if you need them for other accessories. It is easy enough to add these couple wires while running your fish finder wires and will save you possibly hours of work if you want to add a light or something else to your boat down the road.

Another great tip that you might not think of, until your done of course. Then you say to yourself,. “Well dang. I could have just used those to run my fish finder wires.” This is to use existing wires to pull your new wires. Sometimes there are wires that are obsolete for whatever reason. Just use these wires to pull a cord or attach your wires to it if you can and pull it through. This can save a huge headache but keep in mind that it doesn’t always work. Wires are often ziptied tightly under the panel from the factory. When they do this you won’t be able to get the bulk where you added the new wires, through.

This is where the small cord can help. The small cord is much smaller than the wire that you removed then when you attach the fish finder wire there is more room for that smaller “bulk” to get through. It is always worth a try.

Trolling Motor Wires

When running your trolling motor transducer wires from the bow-mounted fishfinder it’s vital that you route them so they won’t get caught in the trolling motor mount itself. A nice clean install is important for protecting your investment for years to come. Be sure to temporarily attach the wires to the trolling motor shaft and deploy and stow the trolling motor in different positions stowing and deploying. This lets you see if you’re wires are safe from becoming crushed in the bracket or anything else. There is so many attachments now on trolling motors like 360 degree transducer rods and livescopes and everything else. Take my word for it do not assume all is clear on your trolling motor transducer wires because often it is not.


For a clean and professional look use, a wire puck is a nice looking puck for covering the hole for all of your wires. With today’s electronics, there are plenty of wires to run. Keeping a clean deck not only looks good, it also helps protect your investment by keeping your transducer wires and power wires nicely ran and out of the many obstacles that can rip, tear or break your wires.  

Fish Finder Connectors

Fish finder connectors are important terminations in any fish finder install. There are connectors that come on the cables. Like the transducer and power connector that screws into the back of the fish finder. The wires that need terminating with ring terminals and butt splices need to be carefully connected. Protect these connections with a little dielectric grease. This grease will protect the electrical connections from the elements. This will give you years of trouble-free connections.

When terminating fish finder connectors there’s a couple of options. These will seal out rain and lake water that always seems to find a way into the boat. The first way is to use fish finder terminal connectors with sleeves built into the terminal. The heated sleeves shrink down onto the wire for a neat termination. It also has glue inside the sleeve to seal out moisture. This glue melts inside filling any void and sealing it from any water intrusion. This helps keep the wire from corroding. Corrosion is death to fish finder connectors.

Fish Finder Mounts

There is several ways for mounting a fishfinder. Some use the fish finder mounting brackets that come with the unit. Some use a fish finder mount for a kayak. You can install your depth finder in the dash using the template that comes from the factory. If you plan to use an adjustable fish finder mount be sure to get a heavy duty mount that will withstand the rigors of the elements as well as rough water. You want a fish finder that will stay locked in place when you run down the lake to a new spot. So many fish finder mounts will not stay in place and you are constantly readjusting them or worse they can give way when the boat hits a wave just right and damage your fish finder.

All of these options have their place. Double check everything before you cut or drill and you will be fine. Be sure you get a heavy duty fish finder mount or you will constantly be readjusting your fish finder on the lake. If you are mounting your fish finder to a kayak you can get away with a lighter ram mount.

In Dash Fish Finder Installation 

Fish Finder Ram Mount

A fish finder ram mount is a very popular way to mount fish finders today. The ram mount is a very versatile option for fish finder installations and there are two great reasons to use a fish finder ram mount.

  1. Ability to adjust your fish finder into many positions
  2. Ability to easily remove your fish finder for security

Ram mount allows you to position your fish finder in many different positions to get just the right angle you need. The ram mount is a handy mount. You can actually use one fish finder and adjust it from the helm to the stern and to the bow. I know some anglers that installed a couple of fish finder ram mounts to turn it 180 degrees. This is so they can see it from the bow seat while they are fishing. Make sure if this is your plan to follow the advice above about actually adjusting the unit to check for clearances before installing the ram mount for your fish finder.

Fish Finder Ram Mount Tip

Because of the weight of the fish finder on the ram mount I recommend bolts and nuts with large area washers. This will distribute the pressure on the base over a much greater area. Over time with rough water and bumpy roads plain screws that screw into the fiberglass and/or wood will finally pull out leaving a nasty hole and could let go of your whole mount with your fish finder and all. I have seen this on a fellow competitor’s boat when he got to weigh in. Thankfully the wires were enough to keep from losing his 9 inch lowrance fish finder.

How To Install Fish Finder Networking

Today’s fish finders have multiple ways to network information from one to another. Fish finder technology is moving as fast as other technologies that we use today. With so many models out there installed on boats today knowing your options is important. Here I will list several ways of networking fish finders and the reasons why you might want to network your fish finders. This information should cover any fish finder you might have installed in your boat that you want to network.

Why Network Fish Finders

One reason you might want to network with two or more fish finders is convenience. By networking the unit in the console to the unit in the bow you can mark a spot while driving the boat and that mark will automatically show on the unit in the bow. This comes in handy when idling with the big motor searching for likely fish holding cover then moving to the trolling motor to fish them. With the cover now marked on the bow unit the angler can move from one mark to the next without looking at the unit in the console. This can save a lot of time and frustration and allows you to mark numerous spots quickly and then fish them to see if they hold fish. This is especially helpful to tournament anglers where time is of the essence.

Another great reason to network your fish finders on your boat is the mapping feature. When you insert a single map card into the unit on the console it is projected to the bow unit when they are networked together. When you mark a waypoint at the helm it automatically shows at the bow. This allows you to purchase a single mapping chip and use it throughout your network of fish finders. These mapping cards are detailed and will help you in your search for contours and creek channels. That might hold fish. 

How To Network Your Fish Finders 

You can Network fish finders a few different ways with today’s technologies. I will list those here minus the newer wireless options that are beginning to reach the market and is gaining popularity. I will work toward adding some information later as it gains more popularity and becomes more common. These networking options will be with wires and the types of cables used in the fish finder networking products today. This website and my experience is fishing and the applications therein. There are many types of networking today with fish finders to include radar and big water sonar and auto-pilot applications. This information will pertain to fishing in freshwater and recreational fishing. 

  1. NMEA 0183
  2. NMEA 2000
  3. Ethernet

NMEA stands for National Marine Electronics Association (of the USA).  The NMEA 0183 was introduced in 1983 and was the standard for networking shipboard electronic devices. It uses a simple ASCII, serial communications protocol that defines how data is transmitted. In a “sentence” from one ‘talker’ to one or more ‘listeners’. NMEA 0183 is in widespread use today and is adequate when one piece of equipment is connected to another. An example is an onboard chart-plotter where the user wishes to integrate the two sets of data.

The NMEA 0183 is superseded now by the NMEA 2000 networking standard. Many devices are designed to communicate using either standard.

NMEA 2000 – Currently the accepted standard across the marine industry is the NMEA 2000. It is much more sophisticated than NMEA 0183. It allows multiple units to simultaneously transmit and receive data.  By including multifunction displays in a networked system the user can then choose any combination of data outputs to be displayed and at any position or situation.  NMEA 2000 has made it possible for the development of integrated navigation and control systems.

NMEA 2000 has a range of advantages over NMEA 0183.  The cables carry the current and the data. This reduces both the cabling requirement. It also eliminates the risk of electromagnetic interference.  You can connect devices using the controller area network or CAN technology. NMEA 2000 not only allows the transmission of data at vastly greater speeds than NMEA 0183 (250,000 bits / second versus 4,800 b/s). Also in a more compact form, making it far more suitable for complex, multi-unit systems. 

NOTE:  NMEA 2000 is a common standard that allows the boat owner to interconnect equipment from different manufacturers.

Ethernet- is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). … Systems communicating over Ethernet divide a stream of data into shorter pieces called frames.

Ethernet cable is capable of transmitting at rates of 10 MB per second and more. It plays a valuable role with marine electronics that process high volumes of data. for example electronic charts and weather overlay information. It is now common to find such units that now offer both Ethernet and NMEA 2000 connectivity.  However, there is no marine standard for Ethernet and equipment from different manufacturers may not be able to communicate with each other.  In addition, unlike NMEA 2000 it does not have the ability to prioritize the transmission of critical data.


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About Ken McBroom 307 Articles
Ken McBroom is an accomplished outdoor writer and photographer. Growing up in Lynchburg Tennessee allowed him many opportunities afield as a boy and young man. Later in life, after Desert Storm, Ken’s wanderlust took him to Alaska to live and work and experience the last frontier. Married now with two beautiful children, Ken now calls Kentucky home where he continues to communicate our American outdoor traditions and the lifestyle it offers.

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