I just saw an ad for a new Hummingbird "Smartcast Mobile Station RF10 Fishfinder" that looks pretty cool. It is a wireless sounder that you can attach the Remote Sonar Sensor to a fishing line & cast as usual. As I understand it, you can then see the bottom contour, depth, & even see fish around your hook. I can think of all kinds of possibilities for this rig, like looking all around your boat for depths, (up to 100ft). You could just tie it to a fishing reel & cast in whatever direction you are curious about the depth. Looks like it will sell for around $200. It has it's own battery so it also would be good to carry around in the dingy for those of us without batteries there. Brent Hodges M/V Friendship