I've been thinking about my rubbish collecting project on the Maas. While looking through a sailing book I noticed a type of net basket used for carrying things in. The frame is an upturned U-shape with a net suspended in the river channel, the opening of which faces upstream. The idea is to catch enough rubbish in the net in order to drag the U-frame from a vertical to a horizontal position. This would automatically close the net entrance. The filled net could then swing toward the river bankwhere its contents could be emptied into a container barge, or simply left to be collected.