I have had depth finder in my yak since I got it in 2006. I used plumbers goop to attach it to the inside hull. have had absolutely no issues with the mounting, but it is a little tough to remove when you change depth finders. traded in my wives outback for a sport model a couple years back and it had a bracket installed for mounting a lowrance transducer, but as previously mentioned it only works for a lowrance unit.

if I had to do it all over again I would probably still goop the transducer to the inside of the hull. with it inside the yak you don't have to worry about it being ripped off of the yak by a random obstruction as you drift down the river

for power I use a deer feeder battery. I have a hobie revolution, and the additional weight does not seem to be an issue. im 6' 4", 215 lbs, and with me and all my gear in it I don't think im overloaded. my wifes kyak is a hobie sport, much smaller and lighter. in her yak I use , if I remember correctly 6 aa size rechargeable batteries in a water proof box. light weight but needs recharging after about 8 hours use.