transducer mounting

I'm in the process of mounting a transducer on my Kraken for a Lowrance Mark-4 and have a question.

The plan is to mount it underneath the kayak via the center transducer specific scupper hole using silicone or epoxy.  There is a long thread in here somewhere regarding scuppers being specific to a brand/model of transducer, suffice to say the Lowrance Mark-4 is NOT specific to the Kraken.

The questions are: 
1.  How flush to the bottom of the kayak is adequate to safely mount the transducer?
2.  Is their a specific type of adhesive  ie silicone or epoxy that tends to work best for this application?

http://s20.photobucket.com/user/microtus/media/20160410_135144_resized_zpsufelbr9p.jpg.html

http://s20.photobucket.com/user/microtus/media/20160410_135136_resized%201_zpsyac5e0is.jpg.html

Neither silicone nor epoxy.  You need to either fabricate a thru scupper bracket ( I believe it was Yakhopper who did a thread on this type of bracket) or purchase a Lowrance Scupper Mount kit.  In either case, depending on the yak, it will generally stick below the bottom of the hull a bit.  You also was the face of the transducer parallel to the surface of the water (or bottom of the lake/ocean floor).

There are lots of threads on here pertaining to transducer mounting.

Neither silicone nor epoxy.  You need to either fabricate a thru scupper bracket ( I believe it was Yakhopper who did a thread on this type of bracket) or purchase a Lowrance Scupper Mount kit.  In either case, depending on the yak, it will generally stick below the bottom of the hull a bit.  You also was the face of the transducer parallel to the surface of the water (or bottom of the lake/ocean floor).

There are lots of threads on here pertaining to transducer mounting.

^^^^ this!!! the scupper mount kit with some wire plug caps will be not only clean, but perfect! my buddy has the kraken elite and did that setup... wish my malibus could use the setup because its cleeeeaaaannn!!  west marine carries the kit and wire caps... if you have questions let me know!!

Why not use something like Goop ?   

Why not use something like Goop ?

You could I suppose.  Seems like it would take a good bit of it to seal it up in the scupper opening.  An option.  Would be better than silicone.

Why not use something like Goop ?   

Why not use something like Goop ?

You could I suppose.  Seems like it would take a good bit of it to seal it up in the scupper opening.  An option.  Would be better than silicone.

With such a nice kayak why even try to "ghetto rig" a transducer like so?? That's my question... Pay $28 for the transducer scupper mount and $6 for the wire cap and you're rolling in style, not to mention, you get to look at a pretty "Lowrance" logo on your scupper hole / plug rather then some ugly goop and a bare wire

Lightfoot,    If you decide to adhere it with Goop,  just a small amount is needed.  About the amount you'd use on a toothbrush.    Don't overkill on that stuff, as an adhesive, it's pretty tough.   Tape it into place for 24 hours until it cures.   
    Silicone won't stick to Polyethylene...  very few epoxies do.   

      I wouldn't worry about the transducer being below the hull a bit.  Those can take a lot of abuse. 

I'm a Jeeper, so first thing that comes to mind is weld something, second is duct tape and tie wire.  The adhesive was third on the list.

Good info on the lack of adhesion to polyethylene, learn something new every day.  I've looked at the scupper mounts.  I think with the size and shape of the center scupper on the Kraken, the transducer will sit pretty low.  I'm trying to tuck it up into the recess as best I can.  I started tinkering with a short piece of pvc pipe last night that should tuck it up nice and tight but still exploring options.  I've got lots of dead time this week staying at a hotel to surf the www.

The west marine wire caps were already in the plan.

Thanks all for the feedback.

I would either buy the Lowrance scupper transducer kit OR build my own mount using simple pvc.
http://www.theplastichull.net/2015/06/25/how-to-install-a-lowrance-skimmer-transducer-fish-finder-on-the-kraken/
http://jacksonkayak.com/blog/2014/03/18/jackson-kayak-big-rig-lowrance-elite-5-hdi-scupper-transducer-mount-lowrance-elite-5-hdi-fish-finderchartplotter-install/

I LEXEL'd my transducer, inside the hull, 10 years ago this month....still seeing fish! Who says shit don't stick to kayak plastic?

I LEXEL'd my transducer, inside the hull, 10 years ago this month....still seeing fish! Who says shit don't stick to kayak plastic?

Lexel is amazing!! So clear and awesome for transducers. Tough to take off for warranty issues if you ever have some down the road.. But hey, sure works good!!! I used it in both my tarpon 120 & 140 after cutting out a foam transudcer cup, too bad the Malibu hills are so angled, it'd be almost impossible to use this method of mounting again!

Having a kayak that was made for a scupper mount to be used however, I would just invest in it and call it a day.

Out of curiousity what transducer do you have? I have the Elite 4 (same as the mark) but my transducer is the 50/200 and I don't think that would work on the krakens scupper hole anyways (too wide). If you have the 83/200 or 83/200 455/800 HDI model it should work perfectly... Otherwise you'll want to make a cup and shoot through the hull...

Lexel- I used that stuff once,  I used it glue my transducer in my 2nd OB hull. I used to store the kayak from my homes ceiling. (Upside down)  Well after a particularly hot summer   as I prepped the kayak for some trip I looked at the transducer and found that the lexel- had got soft and let the weight of the transducer pull the lexel- down. (Remember kayak is upside down) when I noticed the transducer it was suspended about 3" off the hull floor! Since then.  I use a water bath mount in hull.


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 Lexel isn't the same as Goop.   I've tested and compared the two.   OK for sealing a flush mount rod holder, but doesn't remain firm or adhere like Goop does..
        I use a product I get from my roofing supplier. "Flexible Seal"   I think it's the same re-packaged formula as Goop.     Designed to hold up on a hot roof applications.     It's a bitch to remove without using a heat gun.