I am looking to add a Portable type of Fish finder to a canoe. It would need it's own battery supply, I don't want to have an external battery. Years ago I had a bought a weird one at harbor freight, that I was very unhappy with. I see many on ebay like that model. I'd mainly want some fair bottom detail. So what do you recommend, what should I stay away from? I am usual out 5-6 hours and move around a lot. I've seen the stick type and the bag type. Don't have lots to spend on this. What's my best bang for my buck?