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Kayak Through Hull Transducer Mounting Guide

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I have been getting a lot of questions about how I have my depth finder set up on my kayak. I wrote this up about a year and a half ago and posted it on a few sites. I copied it over to here to share with everyone. This setup has been working for me for a long time now with no problems!

I thought I would try and share some info I have learned about mounting a transducer in a kayak/canoe. I know there are all sorts of ways to do this, but I found this way to work very well for me and thought I would pass it on. This is a wet mount, through hull installation. In a sense you are going to install a box full of water to the inside bottom of your kayak and place your transducer in the box. I like this installation method because it is easy to take back out (no glue on your transducer) and it is inside your boat (no breaking it off on a rock) The only real bad thing is you will lose some temperature accuracy if your unit is equipped with a temp readout.

Not much of a writer, but here goes nothing.

Here is what I did. (Luckily I did take a few pictures back when I did this so they will help you to understand what I am talking about)

First you will need a 4x4 utility box from Lowe’s with a detachable lid that has a gasket (about $8.50)


Cut about an inch off the bottom of the box (you are cutting the bottom out of the box, measure the height of your transducer and make sure you leave enough height for it to fit inside the top part with the lid on) I used a grinder with a cutting blade to do this.


Trash the bottom and clean up the upper half. I used a sander and it went pretty easy.


Now decide where you want to install your transducer box. I mounted mine inside my front hatch in between the scupper posts. I picked this spot because it was very stable and doesn’t flex much because of all the extra supports.


If your spot is flat then you can move on to the next step, but if your spot is v shaped like mine you will need to contour your box to fit.

I did this by laying the box where I wanted it and using a sharpie to mark the angles I needed to cut. I used the grinder again and cleaned it all up with the sander.


Now your box is ready to glue to the bottom of your kayak.

You will need to make something to keep your transducer from flopping around in the box. You will need a piece of Styrofoam that is the same shape as the inside of your box. It can be a little shorter, but needs to be pretty snug around the sides. It needs to be snug, but also needs a few loose spots to let the water pour down to the bottom under your transducer.

Lay your transducer on the Styrofoam block and trace its shape. Next cut out the shape, but cut on the inside of the lines. You can always make the whole bigger, but you can’t make it smaller (we are looking for a snug fit) Test fit your transducer and trim if needed to make a nice snug fit.



Now take the lid and drill a hole just big enough to get your transducer cable connector end through.


This pretty much takes care of the box modifications.

Now place your box where you want it on the kayak bottom and trace around it. Remove the box and sand the area well so the glue will adhere properly.

At this point I also sanded the bottom of the box about a half an inch up the inside and outside of the box. That way any glue that smooches up will stick to the sides.

You will need some sort of glue\adhesive to attach the box to the bottom of your kayak. I used some stuff called professional welder that I got at Lowe’s. It says it will weld pretty much anything, and it worked great for me.


Now apply a generous line of glue on the bottom of the box and around the shape of the box on the bottom of your kayak.


Place the box on the kayak floor and place some weigh on it and just leave it alone for a few days to dry.


After a few days I removed the scrap metal I used to put pressure on the box and then applied a layer of aquarium sealant to the inside of the box on the bottom (black sealant). This may be a little overkill, but it didn’t hurt. (Let this dry for a day or two before moving on)


Now all you need to do is just put it all together.

First run the connector end of the transducer cable through the hole you cut in the lid. Run it from the bottom out the top.

Now take the Styrofoam block and place it in the box. Press your transducer into the Styrofoam.


Slide the lid of the box down your transducer cable and screw it onto the box.

Now fill your box up with water. I used some bottled water to do this. I think distilled water would be a good choice also. I read where some people used river water and it caused the water to get nasty and green after time. I left my box unopened for several months and the water was still crystal clear when I opened it again. Fill the box till water comes out the hole, and then rock your boat a bit to make sure water runs all the way down under the transducer. If the water lever goes down after the rocking you will just need to top it off with water.


Now you need to seal the hole on the lid. I used a rubber cork from Lowe’s that I found in the faucet repair section. The cork (orange) had a hole in it, and I just cut it up the side. Now it will slip on the transducer cable and slide down to the hole and press it in. At this point I called it good. But you could use some sealant or glue to lock the cork in place. I didn’t have any trouble with mine leaking, so I never messed with any sealant. This made it easy to change out when I got a new unit for Christmas.


From here just route your connector end of the transducer cable to the head unit, and connect your power cable to your battery and you are done.

I am using a 7amp 12Volt battery with homemade Styrofoam cradle, which will last all day with no problems, and doesn’t weigh all that much.



It really isn’t all that hard and it does work well. Every installation will be different, but this gives you a general idea of how it can be done. Hope this can help someone on here that may be looking at mounting a sonar on a kayak or canoe.


Hit the water and have FUN!!!! thumbsup.gif

Edited by SouthernSam

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Thanks for posting this :thumbsup2: I'm not ready to buy a kayak yet but when I do I'll definately come back to this.

Edited by bowoodsgreen

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i missed the step in the next to last pic about the adult beverage......

i missed the step in the next to last pic about the adult beverage......

that should have been implied simply because it was a men's tutorial :lol:

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