Transponder mounting - advice needed

Just recently my trusty fishfinder met witha premature end due to some corrision from the salt. The power pin broke off while cleaning. Old fishfinder and no parts available for repair. So I upgraded to the raymarine element 7hv. Now I am having to redo most of my mounting and how my deck is arranged. The old transponder was attached to a trackball mount (RAM) with the track mounted near the carrying handle on the right. The problem I am having is that the transponder is really big and heavy. Too much for the scotty arm that I used for previous FF. And I have an older Outback that does not have the transponder mounting on the bottom of the hull. So I am looking for a solution to securely mount a large transponder over the side of the kayak that can handle the weight and size of the new transponder.  Any advice would be appreciated!

Numerous times in the past, Ive put smaller transducers in the hull. It requires rigging a well of sorts in the hull, that will hold water. I use duct putty to adhere a section of 4" diameter PVC to the hull inside the front hatch. It worked flawlessly for me, and is much cleaner than having the transducer hanging of the side, catching weeds n such. Maybe you can construct something similar for your larger transducer, maybe not, but it's something to think about.

I traced out transducer on foam pieces with Velcro in middle and used marine goop to hold it togeather and to the bottom of my revo hull. I hear sidescan  units(I use chirp) don’t work shooting thru hull? 

I still have a couple transducer mounts that went on the side of my kayaks.  Both were homemade, the first is a piece of plastic cutting board that attaches to the tracks mounted like on an Outback.  It gains added stability resting on the top of the grooves where the tracks are installed.  It works on my 2015 Outback as well as a couple other kayaks.  The other (smaller one) mounts on the side of the kayak with a powerful magnet that has another magnet mounted inside the yak.  This one is from my Trident 13 and has worked great.  It does occasionally tip back when cruising.  You can find more photos and info in the archives - the posts are several years back and the original posts were by T-13 who owned the yak before me.

Another option is to leverage your scuppers for mounting the transducer. Long story short I paid the idiot tax when I used non-stainless bolts in my transducer pocket and wound up breaking two of them off. I devised the following method for mounting a transducer on the bottom of my hull via the scupper.... Pictured is the application on my revo 13, but it also works on my Adventure (which does not have a transducer pocket). Only thing is you need to baby the hull to avoid damaging the transducer. Probably harder to do with the heavier Outback.

Happy to provide more pics if you consider going this route.

Thanks for the ideas! I am leaning toward outside the hull mounting so I have the option of using the side scan.
Now I need to start tinkering and build something and get out and start using the FF to find the fish!!  Will post the final configuration when I have it complete.

This guys make a pretty heavy duty track mount product.  I used one for a while before using the factory mount on my old town.  All aluminum so kind of pricey though
https://fishfindermounts.com/transducer-mounts-deck-mount/

Berleypro makes kydex transducers covers. I’m thinking about getting one myself. Here’s a link to the website https://www.berleypro.com/product-category/fishfinder-accessories/transducer-mounts-and-accessories/

@bugboy et al;
Guys look through our Drillin and Cutting threads. There are dozens of ideas and discussions on mounting transducers. Probably the most famous being "shoot thru the hull, shoot me in the head"

There is (maybe was, it was back around '09 or '10) even an article on how to build a transferable "spine" so you can move your whole FF system from yak to yak or yak to power boat, and back and forth.

I made a swing arm out of 1" PVC.  Super solid.  Will pivot forward or aft for clearing weeds or to get away from bottom/rocks.