I recently purchased a Humminbird 859ci HD DI KVD Combo.
I set it up as a portable with a small battery, bag, makeshift transducer mount on a piece of plastic pipe, etc and have been using it for ice fishing. I have both the Navionics + and Hotmaps Premium for Lake East.
If you like, we could meet sometime and you can try it out on your boat? Just don't be surprised if I drop a line in the water while we're at it
I am near Blairsville, PA. A little bit of a drive, but I am interested in fishing the bigger 3 Rivers areas this summer with a (hopefully by then) restored boat.
Might help us both out a bit. Drop me a PM if this sounds interesting to you.