Barge, at the Melvin Price Locks and Dam, Alton, IL The barge was tied up (moored?) in the area between the locks and the shore. I'm guessing they were hinging out in a safe spot during the high water..
There were a couple of workers moving around on it. In fact, the spot of yellow in the lower left is the reflection of one of them.
@ludwigsdiana @shannejw
Thanks both!