Fish/Depth Finder recommendations for U-boat

[BiggDirty]

Hey guys,

Thinking about purchasing a fish finder for my u-boat mainly to find depth and structure (Fish ID would be a bonus). I was just wondering what everyone out there uses and any advice before looking into purchasing a setup? Some requirements would be lightweight & portable, easy setup and a transponder setup that would not get in the way.

Thanks.

[fishaddict]

im using a eagle 300 portable it tells u depth shows structure water temp and fish depth it uses 8 AA batteries that easy last a 14 day on the water works quite well