Posted by Tyler Wallander on September 14, 19102 at 22:46:16:
In Reply to: Info on Caissons posted by Jim on September 14, 19102 at 18:18:19:
After the Chicago Fire, they threw the debris into barges, which were dumped in the lake a couple of miles offshore in 45-55 feet of water. The Caissons is the debris field from those dumpings; and actually there are a couple of debris fields out there. I've also heard that some of the barges just sank with all of the debris aboard. One person was recently showing off a beer stein taken from one of those barges.
The Caissons itself looks like sandy bottom with lumps covered with plant growth and zebra mussels. After 130 years, you can't just expect all of the debris to be lying there for you to recognize. You have to swim slowly and look for anything unusual in the bottom formation. Recently, I found a teapot lid that was completely covered in sand, but you could see a circle formation in the sand, which is not usual, so I was able to brush off the area and uncover the lid. Someone else on the same trip found a brick that was still charred, and another person found a plate from the Palmer House. Sometimes you don't even find anything. I've dove the Caissons three times, but have only found stuff on the third trip.
Because there are no landmarks out there, the only was to safely navigate the area is to tie a reel off to the anchor chain and do search patterns off the reel.
-taken from prior post
sorry i dont know the GPS numbers