Floating weir skimmers use this same trick to suck up the oil floating on the surface of water, except this tube is more than just a cup. It has a tube at the bottom that sucks the oil and oily ...

At the front part of a skimmer there will be a floating door or weir, the weir's job is to restrict water flow into the skimmer and only allow the top layer of water in, ...

For instance, the Coast Guard Vessels of Opportunity use weir skimmer systems that collect oil using floating separators that disrupt the water-oil interface where the two liquids meet.