Why not just purchase a portable sonar device? You can find some affordable entry-level options like the one here from Amazon!
LIMINK FX02F Portable Sonar Fish Finder, 3.1-Inch LCD Screen, 90° Angles Detection, 328 FT Depth Detection, Fish Depth Finder Transducer Detector for Kayak, Boat, Pond, River, Lake, Sea & Ice Fishing
Buy LIMINK FX02F Portable Sonar Fish Finder, 3.1-Inch LCD Screen, 90° Angles Detection, 328 FT Depth Detection, Fish Depth Finder Transducer Detector for Kayak, Boat, Pond, River, Lake, Sea & Ice Fishing: Fish Finders & Depth Finders - Amazon.com ✓ FREE DELIVERY possible on eligible purch... Read more
Try this one from Amazon.
Why not just purchase a portable sonar device? You can find some affordable entry-level options like the one here from Amazon!