Help me outfit my boat.

https://topkayaker.com/

I had a couple of tarpon 140s and they worked great. As others mention mounting the transducer inside the hull is the way to go. First time I used Goop and the second time I used plumbers putty. The putty was way easier for me. I was worried it might fall off but it never did even though I transported it upside down. Besides, even if it came off you could just stick it back down. I tied my battery to the posts that run from top to bottom inside and never took it out. I started with a battery box but eventually switched to just covering the connections with silicone caulk and it has been problem free for years. I used a screw type waterproof connector with enough slack for me to reach from the hatch and would connect it to the fish finder or charger when needed.  I mounted my fish finder on a ram ball that I mounted in the cup holder so it was out of the way. I ran the wires through a grommet a bit above the cup holder so they would be out of the water. This worked great for fishing but was not the best for crabbing because the traps would have to lay on top. I just put a bag over the fish finder and pushed it flat when I was pulling in pots and never had a problem. I mounted a scotty holder to the flat part above the fish finder.
I don't have those kayaks anymore but I found an old picture where you can see the ball and scotty mounts if you zoom in. I found another picture that shows how I made racks for crab traps on case you want to do that.

I actually bought this 140 from jp52 and can tell you that this setup works really well. 
Kevin

..
I actually bought this 140 from jp52 and can tell you that this setup works really well. 
Kevin

I'm glad its working well for you. I caught a ton of fish and crabs from it.

John