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Foam puck and water transducer installation

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There's a few ways to install a transducer but the way that I've done it for the last few kayaks is the foam puck and water method. It's simple and if there's any mistakes made it's easy to hit the restart button without damaging your transducer.

• First, get a piece of your favorite closed cell foam. I like jumbo pool noodles for their frugality. About $1 each for a 6' length. You can use the scrap to make all kinds of other things.

• Cut a 2" thick slice off one end. On the cut side you'll put your transducer over it in the center and trace around it using a black marker. Cut inside of that line so when you push the transducer inside it's held snugly in place. *The puck in the pic is pretty worn and dingy since it's been recycled. Now installed on it's 4th yak.

• Use some sandpaper to lightly sand the area where the transducer will go then wipe it clean. I don't think it really matters where but it must be flat and level to get it shooting straight down. Most people like it accessible through the front hatch in a place where it's a little out of the way.

• Put your favorite marine adhesive on the foam and press down in the install area. I like to put a bead on the outside edges of the puck also to make sure there's a good seal. Put something heavy on top of it and let it dry overnight.
   *marine or plumbing Goop work well and are easy to remove. Some use epoxy but I can't comment
     on it's performance since I have no experience with it.

• Once it's dry you'll notice that some Goop oozed into the area where the transducer will go. With a sharp Xacto knife trace the inside. Don't push too hard, you only want to cut the Goop. Then remove the scrap.

• When you're ready to fish, fill the puck with water and push the transducer in until it's snug and water is gurgling out. Make sure it's level and you're ready to fish!

For others that have used this method feel free to post up pics.
BTW a big thanks to whoever invented this!


Thanks Zee--very helpful post.--this chore is on my todo list and I'll have to get to it soon.

Thanks! this is is the method I am going to use instead of the temporary test I posted here on my blog.

An excellent method, and neater than the somewhat sloppy-looking putty dam.  It might be good  to use 2 coats of Goop on the puck---coat the botom, let it dry overnight, and then another coat to glue it down.  That will keep water from seeping out the bottom edges, which happened to me with one coat of Goop on a puck made from black packing foam, the pool noodle foam might be more impervious.

The Hobie Mirage drive drops through the boat and the flippers extend into the water. When mounting a transducer it is important to place the transducer such that when extended the mirage drive flippers do not impinge on the transducer sound cone.

A typical transducer sound cone is 60 degrees. The turbo flippers extend 16" below the hull. With basic trigonometry we can calculate the transducer must be at least 9.25" from the edge of the flippers. If the transducer is mounted just forward or just aft of the mirage drive hull cut out, when the flippers are extended they will be in the transducer cone. To clear the flippers I chose to mount the transducer just aft of the crotch hatch. This places the transducer under the seat, near the center of the boat.

Cut foam installed on hull. A nice oozed bead of Marine Goop can be seen around the foam.

Use water first and see how it works.  I used water then changed to marine grease. 

Note from the future: ... It appears that after a year or two the grease seeped past the thermocouple button into the transducer and degraded its performance.  After struggling for a year trying to figure out what was wrong, I'm back to water with a new transducer ... YMMV ...  

One more note from the future:  cut a small notch in the foam extending forward from the point of the transducer, and cut a small notch out of the foam behind one back corner of the transducer.  This will allow water to flow under and around the transducer when filling the block regardless of how tight a fit your transducer is.  These are tiny notches.  A large syringe works well for filling - NO NEEDLE.  Now, onward into the past ...

The final step was to put about an 1/8" layer of grease in the foam cup and press fit the transducer into the foam until it contacted the hull. DO NOT USE TOO MUCH GREASE. Unlike water the grease is very viscous and nearly impossible to squish out the excess without blowing out the seal on the foam reservoir. Also floating the transducer on a layer of grease above the hull will GREATLY affect transducer performance. I had to remount the transducer 3 times, with less and less grease each time.  Learn from my experience.


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