Can anyone say "snatch rope".
I did the same thing one spring in the Grenada lake bottom. It looked dry, but when I broke throught the 2" crust there was nothing but blue mud. I had a chain and a guy in a 4 wheel drive tried to help, but it would not budge. The only way out was a 50' snatch rope hooked to a 4 wheel drive. Would not think a rope would out pull a chain, but I learned something that day.

1. Just cause it looks dry and looks like a good crossing don't mean squat.
2. if you play in the lake bottom, have a good snatch rope handy. A chain will do no good down there, unless it is slowing down your trolling speed.