For those without a vex and wanting to know the rough depths, here is a neat idea...
If you have an old baitcast rod and reel, you can make a home made depth finder.
1. Cut the rod down to about 2 feet.
2. mount an eye at the end. Does not have to be fancy just something to position the line.
3. Add different colored braided or nylon lines at 10 foot and/or 5 foot increments. Use a blood knot between lines.
4. Tie a heavy weight to the end.
I have this setup and it works great for finding the rough depths.
Brian