As the title says I set up a Humminbird fishfinder without drilling a single hole anywhere. the fishfinder is a Humminbird 788ci unit, a little overkill perhaps but I use the same FF in my boat also. I used Mad Frog's "Liberator" mount that sits in a Scotty clamp on rail mount. the Liberator mount has a transducer arm that swings out and down into the water as an upside down "L" shape. I also mounted four Scotty clamp on rod mounts and I use them for two Scotty rod holders that sit in risers, I did have to shim the clamps with a 1/8" thick rubber shim. the battery is a 5 amp sealed gel battery in a plastic waterproof box from Walmart that has the wires passed through a hole sealed with a rubber gasket. I charge the battery with a battery tender. the battery wires that pass through the plastic box are from a battery tender with a 4 amp fuse to protect the FF. I estimate 10 to 12 hours of usage of the FF before the battery hits 8.0 volts and shuts off. if I am camping and don't have access to an outlet to charge with the battery tender I connect the battery to a 12 volt plug on a jumper battery I have in the truck.
I take the rod holders off and store them when I launch and beach the yak so I can use the paddle as needed. I do have to be careful I don't smack the FF while paddling on the FF side.
overall I am satisfied with how things turned out, no holes to drill, no transducer to goop in the hull, no wires passing through the hull, the FF is very easy to read and easy to reach the controls on the FF without stretching, easy to reach and watch the rods in the holders and they are right next you to easily reach.