Mounting a fish finder on your boat involves three things: the mounting bracket, the display and the transducer.
Mounting bracket – Transom mounts are usually standard (in-the-box) with most fixed fish finders and come with detailed instructions on how to mount it onto your boat. Although it's reliably easy to do on your own, please read the instructions from front to back so you do not end up damaging your boat or having to reposition it later on. After all, you are drilling holes below the waterline of your boat so you'll want to get it right the first time. If you want to play it safe, you can always try asking your dealer to do the installation for you.
Transom mounted fish finders are ideal for personal watercraft (rowed or paddled), sailboats, outboard, I / O powered boats and jet drives because they're easy to install and generally get the job done quite well.
Tips: A boat's contours (rivets, ribs, dents) will produce distinct turbulence and air pockets which affect a fish finder's performance. Select a nice flat spot that's free from protrusions and ribs. You will also want to keep it away from the prop. Make sure the mounting area for the transducer will remain in contact with the water at all times to avoid cavitation (In other words, do not mount it too high up). Remember to keep everything away from the bumpers so nothing gets damaged when you have to trailer your boat.
Display – The most important consideration when deciding where to install your display is access. You'll want to be able to see the display from where you're actually fishing. Look into manufacturer options for gimbals, flush in-dash, and swivel mounts. You should also look for a display you can easily read even under direct sunlight; otherwise, it will not matter where you position the display since you still will not be able to read it. We'll discuss other considerations for displays like LCD, CRT and LED in another article.
Transducer – Aside from transom mounted transducers, you can also choose between in hull or through hull transducers. As the name suggests, through hull transducers require drilling a hole through the boat's hull to mount the transducer while in hulls will basically send a sonar signal without requiring any modifications to the hull. Be sure to do your homework before attempting to install a through hull transducer on your own.
It's important to note that the material used on your boat's hull will determine what kind of housing your through hull transducer should have. Here's a quick look at some considerations to make in choosing a transducer for a fixed fish finder.
Hull material: Wood
Transducer housing material: Bronze
Reason: Wood expansion could damage plastic housing and result in a leak.
Hull material: Metal (steel or aluminum)
Transducer housing material: Stainless steel, plastic
Reason: Bronze housing requires insulating fairing. If your boat has a positive ground system, do not use metal transducer housing.
Hull material: Fiberglass
Transducer housing material: Plastic
Reason: Easier to seal plastic to fiberglass