Well I got my fish finder today. Since I am basically starting from scratch I have alot of things to order. Therefore I did not get the little nice things like scotty mounts. That being said, I am pretty happy with how the install went.
I made my own battery box from a ammo box I found on amazon.com for 10 bucks. I found some "wire seals" for $1.50 (instead of the $9 to $20 you pay for "WIRE SEAL" online at kayaking places) While I was on my job site today I found a long length of heat shrink- I hea shrunk my whole cable, and even tripple shrinked it where the cable comes out of the hull to attach to the fish finder.
I found some inexpensive connectors at home depot and made a quick disconnect near the battery. I used 4 bricks of duct seal to install both the battery box in the hull and the transducer in the hull. I even turned the boat sideways and you can see the battery is still hanging on.
Well here are some pics. they may not be in order.