Mounting Transducer For Kayak

This is my kayak as you can see the keel area has the middle groove does the transducer need to be below the keel or can it be set in the groove to give some protection

 

I have seen several method to attach a transducer to a kayak. Air will attenuate or kill the transmission of sound so you need to find something to take the air away and that will allow sound to transmit. I would recommend trying it on a temporary basis before doing anything permanent. I use to do UT (Ultrasonics Testing) in another life. We used a glycerin based product but Petroleum Jelly will work just fine and its cheap. Put a good amount of that (1 inch thick) that on a flat spot of your hull and place the face of the transducer in it. This will allow the sound to be transmitted between the interface. If your mounting surface is not parallel to the top of the water your sound will be sent at an angle. This will affect your signal. So just play with it in some shallow clear area where you can see whats going on. Once you're happy your good to go . If you want to make it permanent you can silicon it to your hull.

 

What I want to do is mount transducer thru scupper hole. does there need to be 360 deg clearance or is it only below. As you can see from the original pic there is the gap in the middle of the keel so transducer sides wouldn't be below this space

 

Maybe I am looking at the wrong picture. If your yellow kayak shown above in the kayak you're mounting to I don't see any scupper hole. These are on SOT kayaks and allow the water to pass. Yours does not appear to be a SOT to me. So you have a single wall bottom hull. YOu will need to mount it on the inside of your kayak. Or rig something that goes over the side and puts the TD in the water.
Only the face of the TD needs to be in contact the rest is just housing. You can see where that is by putting some jell on the TD and tapping your finger on it. You should see the screen make funny movement or pulses. Thats your face where the sound will be transmitted from.
If your going to mount the TD in the Keel Strip (Grove) that runs full length on the bottom of the kayak I wouldn't recommend that but the transducer can protrude below the bottom but you cant drag you kayak around and have the ground or what ever rub it. I would recommend finding a location out of the way inside your kayak that doesn't bother you while your sitting or doing things in it. You of course also need to pick a location where water contact will be assured and the angle would be a near to parallel with the water surface as possible.

They have lots of guys showing how to do this on YouTube . If you mount with silicone or any other couplant you need to ensure nothing moves until its set up fully. YOu also can not have any, any, any air between the transducer and the mounting surface. If you do your signal will not be transmitted to the water.

Its not hard to do but you cant be stupid or it will bite you. Good Luck

 

There are actually four scupper holes in the middle off the keel hard to see because they are stepped. So the transducer would be protected on the front and the sides, I am thinking mounting it on the inside may be the best way to go. I am thinking of an upgrade to an actual fishing kayak so didn't want a permanent mount. I have a crescent kayak splash II. It is a tandem that has three molded seats I sit in the center seat when I go solo.

 

I would just add one thing. If your kayak has scupper holes then it must be double walled on the bottom and if that's the case you cant mount the transducer on the inside as there is a air pocket between the two bottoms. On my SOT I made a PVC bracket that went into 2 scupper holes and ran that over the side and mounted it that way.

Good Luck

 

Sorry been out for a while . How did you finally decide to mount your TD? Hope it worked out for you and your seeing fish.

 

I need to do this too. Still researching different ways to do it. I like this idea best so far.

 

Air is a sound attenuator meaning it kills sound from traveling far. Remember we are speaking of Ultrasound. All materials have the ability to transmit sound. But as the material becomes less dense like wood styrofoam etc air is within its structure and that dampens of attenuates the sound. So you need to find a substance that does not have air as part of its structure. In doing Ultrasound in the construction industry Glycerine , vaseline and other such products are used to couple transducers to whatever it is you're trying to scan.
You could use epoxy to make a permanent attachment to your kayak and the sound would penetrate through your hull as plastic is dense and no air is in its grain structure. I would not drill a hole. If you look at the transducer used for fish finders what you are seeing is the housing not the transducer. they are epoxied into that housing making them easier to handle. Kayaks are typically a HDPE plastic. It's difficult to get things to stick to it permanently. That's why plastic welding it best for repairing holds or cracks. It I would you I would try using some silicon to stick the transducer to the kayak. Just make sure you don't squeeze any air bubbles into the glob you put on the kayak then carefully place you Transducer in the silicon mound making sure the transducer is properly aimed at where the water surface would be and let it set up well before trying it. I would also prep your Kayak surface prior to applying the Silicon. You should be able to get info online . I would be using flame to break the surface tension of the plastic which would help it adhere..
If all of this is too much rig up something that clamps to your kayaks side (PVC pipe) and zip tie you Transducer to it. THere is probably tons of stuff to look at on YouTube.

 

Here is a simple option to consider...

 

That's great info. Is regular 2 part epoxy generally too thick or just a small amount sufficient ?

 

Hope you don't mind my 2 cents but I would follow NG I was have the same issue was not getting depth and all jacked up readings. I applied a fear amount of clear silicon to the inside of the hull and works perfect. They say that your temp readings and depth will be off but have had no problems as of yet

 

How accurate of a reading can you get with it being mounted inside the hull?