Thanks for the input, already made the jump though. Decided on the Deeper Plus pro. Much better graph and sonar than the i bobber. Haven't tried it out of the kayak yet but have used it on a couple local ponds. Seems to work pretty well. Even has a built in GPS in the unit so it can graph out lake / pond bottoms. Not too worried about the phone, waterproofing isn't a problem as I have my phone on the kayak already anyway.