These decoys actually are thrown OVER the line, and then pulled up to perch on the line with the fishing line.
You either tie the fishing line to an achor, or have a weight that you adjust to the height of the line.

They were VERY effective and I can't remember the guy who had them.
I'll try to find out on my end, and I'll let everyone else know too. They worked like a dream, and were very easy to position and remove when done.