Skip to content
header image



Installing a Sonar in Your SOT

Before setting my sights on reservoir fishing, I thought that I had no need for a depth finder.  Carefully studying a rivers surface, I could foretell the locations of ledge rocks and boulders by the boils they deflected to the surface.  While fishing a jig or tube, I could note the angle of my line and know how deep the pool was in front of me. A sensitive graphite rod coupled with no stretch braided line helped distinguish between a sandy, rocky, muddy, or gravelly substrate. 

The jig as probe tactic worked on the reservoir, but the surface patterns were not at my disposal.  I quickly learned that I was severely handicapped without the aid of a depth finder.  Note that I do not use the term “fish finder”.  A quality unit properly installed can in fact mark individual fish, but most of the time, I am looking for a specific structure to which the fish will orient themselves. 

Having no prior experience with depth finders, I had no clue how to install one.  The installation instructions in the manual of my first unit offered little help, as they were written to the owner of a bass boat.  Not sure what to do, I sought out the advice of a fellow kayak angler who had installed several.  That installation method has evolved with each subsequent installation I’ve done.  Here are three different methods of installation, and explainations why my current method is the most useful for both river and reservoir fishing. 

I sought my advice from fellow kayak angler Cory Routh.  He had authored an installation article in The Sportsman, a Virginia based outdoor publication and mailed me a copy.  It explained the importance of using a slow set epoxy to fix the transducer to the bottom of the inside of the kayak.  Quick set epoxies can leave bubbles in between the hull and the transducer.  This results in the permanent fixation of the transducer that provides a poor signal. 

I ordered a slow set transducer install kit for hull installation, cut a transducer shaped hole in some closed cell foam as outlined in his article, and used this set up for a year and a half in my Tarpon 120. 

When I upgraded to a faster Tarpon 140, I tried a second method so I could reuse the transducer should I switch to a different kayak. 

Instead of fixing the transducer to the hull directly, I cut up a Tupperware bowl and glued it to the hull.  I used a gel type crazy glue which adhered it into place, and completed the seal waterproof with an RTV sealant.  The duct tape seen in the photograph simply holds the transducer cables in place.  When the inverted bowl was fixed to the hull, I filled the cavity with water, lowered the transducer into the water, and used twist ties to hold it in the middle.  This set up allows for transferal of the transducer from one kayak to another. 

A year later I appreciated the temporary transducer installation, as I had again decided to switch to a faster kayak, this time a Tarpon 160.  But in the mean time, I observed why many bass boaters opt to mount the transducer directly into the water. 

While moving from one branch of Prettyboy Reservoir to another with a buddy, I hitched a ride. The boat is an all battery powered Triton bass boat.  From a seated position in my kayak, I clamped my elbow tightly against the inside of his deck rail.  I felt like a rider in a motorcycle’s sidecar. 

While we were underway, I watched the monitor of his new depth finder.  It was a color model, but was inferior to mine in terms of number of pixels.  I watched the amazing detail on his, glancing back to my screen.  His transducer picked up individual fish, changes in bottom substrate, and schools of baitfish that mine missed.  I peppered him with questions on the model, sure that an upgrade was on my horizon. 

While searching in my catalog that night, I was shocked to see that my model was superior in terms of number of pixels. The only explanation I could come up with was that his transducer was in the water, and mine was shooting through a hull.  The next time out, I removed the transducer from the inverted bowl and stuck it in the water directly. 

The difference I observed can be likened to relying on drugstore bought reading glasses, and then replacing them with a pair of prescription spectacles. The difference can be immense!  The only issue was how it would be rigged so it wouldn’t get bashed off when I would run rapids or back into some rip rap.   

My solution isn’t pretty, but it works.  The design reminds me of something out of the electrical section of Home Depot – the Snake Light.  For those not familliar, the Snake Light is a flashlight that has an incrementally pivoting head that retains the direction that you bend it toward. 

To make my transducer shock proof, I ran the cable through the top of the deck and coupled it with a ½ inch thick 3 foot section of plastic coated braided copper cable.  The sole purpose of the copper cable was to provide rigidity.  Using plenty of electrical tape, I coupled the wire and the cable from the transducer head to about a foot beyond where the two entered the hull of the kayak. 

I wrapped the head of the now rather stiff transducer cable around the side handle of the kayak.  This allows me to reach the transducer head easily while sitting in the kayak.  When I need to cover water quickly, I bend the head of the transducer out of the water to reduce drag.   

If I witness a school of baitfish breaking the surface and want to “see” which direction they are traveling, I  can reach into the water, grab the transducer and turn it outward instead of downward to find them.  This trick works best when you have the range set at a certain number within your casting distance, say 100 feet for example. 

I prefer the snake light installation, but if stealth is more important than quality of signal, one of the other two methods might be considered.  The transducer in the water creates a great deal of churning noise when moving a kayak through the water quickly.  This can spook fish as much as whacking the paddle shaft across your hull. 

Whatever method of installation you choose, know that the depth finder is your tool to break away from the crowd.  Stop beating the banks like every other angler out there.   Learn how to read off shore structure, and tap into what most anglers don’t have the patience or faith to stick with.