Want to see if I can get some recommendations for this project.

It involves a two-acre pond built sometime in the '70s. It's on the property of a non-profit family campground and I'm helping kick the fishing up to the next level (at least that's our hope), and make some hot spots that the kids can target, etc.

We'd like to map the bottom of it so we know just what we're dealing with and do some planning. There are rumors that it is 30 feet deep in one spot but no one who was involved in building it is still around to ask.

We can drop a marked rope at points on a grid, but surely there must be an easier way...with a fish-finder or something? I don't have any experience with anything along this line. I experimented on my back yard, using a GPS land-survey app on my Android to plot grid points, but it did not give me reliable enough accuracy (points that were plotted in straight lines on the ground were not straight on the map, for instance). This project doesn't really require tight accuracy, but I was hoping for at least a little more than I was getting.

Anybody have any experience with something like this?

You might check out this thread: http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Main=16939&Number=217431#Post217431

Catmandoo started it about a little device Humminbird makes. You cast out a little wireless transducer, and it sends info back to a small receiver.

I did get my pond mapped, plus three others using the Hunningbird RF-25/35/45. Unfortunately, I cannot recommend the RF-Series of Humminbirds. When they work, they work great. I loved the thing. Unfortunately, I gave up after having three transducers die within about five uses each.

I don't know what killed them. I can only guess that it was the shock of hitting the water on a long high cast. I'm not the only one with these issues. Many figure it was the non-replaceable battery.

Humminbird RF-Series Depth/Fish Finders

The people at the factory were always very nice and polite, but not very efficient or organized. Each time I attempted a replacement, it took many calls, e-mails, and a repeat of my complete history. I was out of warranty when finally I got the second replacement (3rd transducer).

Maybe they are now better made. It would be great if they could make them reliable. When they work, they are really great.

I think some have pretty sophisticated systems that can do it. Don't know how much that would cost. Might be able to get some serious fisherman with one of the neat side / down imaging fish finders to somewhat informally plot it out.